Vinicius Rosa
Degree: PhD
Position: Associate Professor
Affiliation: NUS - Faculty of Dentistry
Research Type: Experiment
Email: denvr@nus.edu.sg
Contact: (65) 6772 6845
Research Interests:
- Quantum condensed matter theory;
- Stem cell research;
- Osteogenesis;
- Neurogenesis;
- Coatings for biomedical applications.
CA2DM Publications:
2023 |
Liu, Shiyao; El-Angbawi, Ahmed; Ji, Ruidong; Rosa, Vinicius; Silikas, Nick Optical effects of graphene addition on adhesives for orthodontic lingual retainers Journal Article EUROPEAN JOURNAL OF ORAL SCIENCES, 132 (1), 2023, ISSN: 0909-8836. @article{ISI:001117827600001, title = {Optical effects of graphene addition on adhesives for orthodontic lingual retainers}, author = {Shiyao Liu and Ahmed El-Angbawi and Ruidong Ji and Vinicius Rosa and Nick Silikas}, doi = {10.1111/eos.12966}, times_cited = {0}, issn = {0909-8836}, year = {2023}, date = {2023-12-07}, journal = {EUROPEAN JOURNAL OF ORAL SCIENCES}, volume = {132}, number = {1}, publisher = {WILEY}, address = {111 RIVER ST, HOBOKEN 07030-5774, NJ USA}, abstract = {The objective of this study was to determine the effects on the colour of adding increasing concentrations of graphene to orthodontic fixed retainer adhesives and to evaluate changes in optical transmission during light curing and the resultant degree of conversion. Two different types of adhesives commonly used for fixed retainers were investigated: A packable composite (Transbond) and a flowable composite (Transbond Supreme). Graphene was added to the adhesives in three different concentrations (0.01, 0.05, and 0.1 wt%). Adhesives without graphene addition were set as control groups. A Minolta colourimeter was used to measure the colour and translucency parameters. Irradiance transmitted during curing was quantified using MARC Light Collector. Fourier-transform infrared spectroscopy was used to record degree of conversion. Data were statistically analysed with the Student's t-test and one-way ANOVA with Tukey's tests (alpha = 0.05). The findings showed that incorporating graphene darkened the adhesive colour significantly and reduced translucency. As the graphene concentration reached 0.1 wt%, samples became opaque; yet, no adverse effect on degree of conversion was observed. The addition of graphene reduces optical transmission of lingual retainer adhesives; the effect increases with graphene concentration.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The objective of this study was to determine the effects on the colour of adding increasing concentrations of graphene to orthodontic fixed retainer adhesives and to evaluate changes in optical transmission during light curing and the resultant degree of conversion. Two different types of adhesives commonly used for fixed retainers were investigated: A packable composite (Transbond) and a flowable composite (Transbond Supreme). Graphene was added to the adhesives in three different concentrations (0.01, 0.05, and 0.1 wt%). Adhesives without graphene addition were set as control groups. A Minolta colourimeter was used to measure the colour and translucency parameters. Irradiance transmitted during curing was quantified using MARC Light Collector. Fourier-transform infrared spectroscopy was used to record degree of conversion. Data were statistically analysed with the Student's t-test and one-way ANOVA with Tukey's tests (alpha = 0.05). The findings showed that incorporating graphene darkened the adhesive colour significantly and reduced translucency. As the graphene concentration reached 0.1 wt%, samples became opaque; yet, no adverse effect on degree of conversion was observed. The addition of graphene reduces optical transmission of lingual retainer adhesives; the effect increases with graphene concentration. |
Cahyanto, Arief; Martins, Marcos Vinicius Surmani; Bianchi, Otavio; Sudhakaran, Deepa Perumbodathu; Sililkas, Nikolaos; Echeverrigaray, Sergio Graniero; Rosa, Vinicius Graphene oxide increases PMMA's resistance to fatigue and strength degradation Journal Article DENTAL MATERIALS, 39 (9), pp. 763-769, 2023, ISSN: 0109-5641. @article{ISI:001065166400001, title = {Graphene oxide increases PMMA's resistance to fatigue and strength degradation}, author = {Arief Cahyanto and Marcos Vinicius Surmani Martins and Otavio Bianchi and Deepa Perumbodathu Sudhakaran and Nikolaos Sililkas and Sergio Graniero Echeverrigaray and Vinicius Rosa}, doi = {10.1016/j.dental.2023.06.009}, times_cited = {0}, issn = {0109-5641}, year = {2023}, date = {2023-08-23}, journal = {DENTAL MATERIALS}, volume = {39}, number = {9}, pages = {763-769}, publisher = {ELSEVIER SCI LTD}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND}, abstract = {Objectives: to characterize the effects of graphene oxide (GO) on polymethyl methacrylate's (PMMA) reliability and lifetime. The hypothesis tested was that GO would increase both Weibull parameters and decreased strength degradation over time. Methods: PMMA disks containing GO (0.01, 0.05, 0.1, or 0.5 wt%) were subjected to a biaxial flexural test to determine the Weibull parameters (m: modulus of Weibull; & sigma;0: characteristic strength; n = 30 at 1 MPa/s) and slow crack growth (SCG) parameters (n: subcritical crack growth susceptibility coefficient, & sigma;f0: scaling parameter; n = 10 at 10-2, 10-1, 101, 100 and 102 MPa/s). Strength-probability-time (SPT) diagrams were plotted by merging SCG and Weibull parameters. Results: There was no significant difference in the m value of all materials. However, 0.5 GO presented the lowest & sigma;0, whereas all other groups were similar. The lowest n value obtained for all GO-modified PMMA groups (27.4 for 0.05 GO) was higher than the Control (15.6). The strength degradation predicted after 15 years for Control was 12%, followed by 0.01 GO (7%), 0.05 GO (9%), 0.1 GO (5%), and 0.5 GO (1%). Significance: The hypothesis was partially accepted as GO increased PMMA's fatigue resistance and lifetime but did not significantly improve its Weibull parameters. GO added to PMMA did not significantly affect the initial strength and reliability but significantly increased PMMA's predicted lifetime. All the GO-containing groups presented higher resistance to fracture at all times analyzed compared with the Control, with the best overall results observed for 0.1 GO.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Objectives: to characterize the effects of graphene oxide (GO) on polymethyl methacrylate's (PMMA) reliability and lifetime. The hypothesis tested was that GO would increase both Weibull parameters and decreased strength degradation over time. Methods: PMMA disks containing GO (0.01, 0.05, 0.1, or 0.5 wt%) were subjected to a biaxial flexural test to determine the Weibull parameters (m: modulus of Weibull; & sigma;0: characteristic strength; n = 30 at 1 MPa/s) and slow crack growth (SCG) parameters (n: subcritical crack growth susceptibility coefficient, & sigma;f0: scaling parameter; n = 10 at 10-2, 10-1, 101, 100 and 102 MPa/s). Strength-probability-time (SPT) diagrams were plotted by merging SCG and Weibull parameters. Results: There was no significant difference in the m value of all materials. However, 0.5 GO presented the lowest & sigma;0, whereas all other groups were similar. The lowest n value obtained for all GO-modified PMMA groups (27.4 for 0.05 GO) was higher than the Control (15.6). The strength degradation predicted after 15 years for Control was 12%, followed by 0.01 GO (7%), 0.05 GO (9%), 0.1 GO (5%), and 0.5 GO (1%). Significance: The hypothesis was partially accepted as GO increased PMMA's fatigue resistance and lifetime but did not significantly improve its Weibull parameters. GO added to PMMA did not significantly affect the initial strength and reliability but significantly increased PMMA's predicted lifetime. All the GO-containing groups presented higher resistance to fracture at all times analyzed compared with the Control, with the best overall results observed for 0.1 GO. |
Phan, Toan V; Oo, Yamin; Ahmed, Khurshid; Rodboon, Teerapat; Rosa, Vinicius; Yodmuang, Supansa; Ferreira, Joao N Salivary gland regeneration: from salivary gland stem cells to three-dimensional bioprinting Journal Article SLAS TECHNOLOGY, 28 (3), pp. 199-209, 2023, ISSN: 2472-6303. @article{ISI:001015656200001, title = {Salivary gland regeneration: from salivary gland stem cells to three-dimensional bioprinting}, author = {Toan V Phan and Yamin Oo and Khurshid Ahmed and Teerapat Rodboon and Vinicius Rosa and Supansa Yodmuang and Joao N Ferreira}, doi = {10.1016/j.slast.2023.03.004}, times_cited = {0}, issn = {2472-6303}, year = {2023}, date = {2023-06-06}, journal = {SLAS TECHNOLOGY}, volume = {28}, number = {3}, pages = {199-209}, publisher = {ELSEVIER SCIENCE INC}, address = {STE 800, 230 PARK AVE, NEW YORK, NY 10169 USA}, abstract = {Hyposalivation and severe dry mouth syndrome are the most common complications in patients with head and neck cancer (HNC) after receiving radiation therapy. Conventional treatment for hyposalivation relies on the use of sialogogues such as pilocarpine; however, their efficacy is constrained by the limited number of remnant acinar cells after radiation. After radiotherapy, the salivary gland (SG) secretory parenchyma is largely destroyed, and due to the reduced stem cell niche, this gland has poor regenerative potential. To tackle this, researchers must be able to generate highly complex cellularized 3D constructs for clinical transplantation via technologies, including those that involve bioprinting of cells and biomaterials. A potential stem cell source with promising clinical outcomes to reserve dry mouth is adipose mesenchymal stem cells (AdMSC). MSC-like cells like human dental pulp stem cells (hDPSC) have been tested in novel magnetic bioprinting platforms using nanoparticles that can bind cell membranes by electrostatic interaction, as well as their paracrine signals arising from extracellular vesicles. Both magnetized cells and their secretome cues were found to increase epithelial and neuronal growth of in vitro and ex vivo irradiated SG models. Interestingly, these magnetic bioprinting platforms can be applied as a high-throughput drug screening system due to the consistency in structure and functions of their organoids. Recently, exogenous decellularized porcine ECM was added to this magnetic platform to stimulate an ideal environment for cell tethering, proliferation, and/or differentiation. The combination of these SG tissue biofabrication strategies will promptly allow for in vitro organoid formation and establishment of cellular senescent organoids for aging models, but challenges remain in terms of epithelial polarization and lumen formation for unidirectional fluid flow. Current magnetic bioprinting nanotechnologies can provide promising functional and aging features to in vitro craniofacial exocrine gland organoids, which can be utilized for novel drug discovery and/or clinical transplantation.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Hyposalivation and severe dry mouth syndrome are the most common complications in patients with head and neck cancer (HNC) after receiving radiation therapy. Conventional treatment for hyposalivation relies on the use of sialogogues such as pilocarpine; however, their efficacy is constrained by the limited number of remnant acinar cells after radiation. After radiotherapy, the salivary gland (SG) secretory parenchyma is largely destroyed, and due to the reduced stem cell niche, this gland has poor regenerative potential. To tackle this, researchers must be able to generate highly complex cellularized 3D constructs for clinical transplantation via technologies, including those that involve bioprinting of cells and biomaterials. A potential stem cell source with promising clinical outcomes to reserve dry mouth is adipose mesenchymal stem cells (AdMSC). MSC-like cells like human dental pulp stem cells (hDPSC) have been tested in novel magnetic bioprinting platforms using nanoparticles that can bind cell membranes by electrostatic interaction, as well as their paracrine signals arising from extracellular vesicles. Both magnetized cells and their secretome cues were found to increase epithelial and neuronal growth of in vitro and ex vivo irradiated SG models. Interestingly, these magnetic bioprinting platforms can be applied as a high-throughput drug screening system due to the consistency in structure and functions of their organoids. Recently, exogenous decellularized porcine ECM was added to this magnetic platform to stimulate an ideal environment for cell tethering, proliferation, and/or differentiation. The combination of these SG tissue biofabrication strategies will promptly allow for in vitro organoid formation and establishment of cellular senescent organoids for aging models, but challenges remain in terms of epithelial polarization and lumen formation for unidirectional fluid flow. Current magnetic bioprinting nanotechnologies can provide promising functional and aging features to in vitro craniofacial exocrine gland organoids, which can be utilized for novel drug discovery and/or clinical transplantation. |
2022 |
Malhotra, Ritika; Halbig, Christian Eberhard; Sim, Yu Fan; Lim, Chwee Teck; Leong, David Tai; Neto, Castro A H; Garaj, Slaven; Rosa, Vinicius Cytotoxicity survey of commercial graphene materials from worldwide Journal Article NPJ 2D MATERIALS AND APPLICATIONS, 6 (1), 2022. @article{ISI:000852419000001, title = {Cytotoxicity survey of commercial graphene materials from worldwide}, author = {Ritika Malhotra and Christian Eberhard Halbig and Yu Fan Sim and Chwee Teck Lim and David Tai Leong and Castro A H Neto and Slaven Garaj and Vinicius Rosa}, doi = {10.1038/s41699-022-00330-8}, times_cited = {3}, year = {2022}, date = {2022-09-09}, journal = {NPJ 2D MATERIALS AND APPLICATIONS}, volume = {6}, number = {1}, publisher = {NATURE PORTFOLIO}, address = {HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY}, abstract = {Graphene and other 2D materials are having a profound impact on science and technology. Unfortunately, progress in this area has not been followed by strict quality controls and toxicity benchmarks. Herein, we report a survey of the cytotoxicity of 36 products nominally labeled as "graphene." These are available from suppliers worldwide and synthesized through various techniques. Detailed characterization suggests that these products represent a heterogeneous class of materials with varying physicochemical properties and a noticeable quantity of contaminants. We demonstrate that the cellular toxicity of these products is not related to a particular characteristic of graphene; rather, it is fundamentally determined by the presence of impurities in the commercially available graphene family materials tested.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Graphene and other 2D materials are having a profound impact on science and technology. Unfortunately, progress in this area has not been followed by strict quality controls and toxicity benchmarks. Herein, we report a survey of the cytotoxicity of 36 products nominally labeled as "graphene." These are available from suppliers worldwide and synthesized through various techniques. Detailed characterization suggests that these products represent a heterogeneous class of materials with varying physicochemical properties and a noticeable quantity of contaminants. We demonstrate that the cellular toxicity of these products is not related to a particular characteristic of graphene; rather, it is fundamentally determined by the presence of impurities in the commercially available graphene family materials tested. |
2021 |
Malhotra, Ritika; Han, Yingmei; Nijhuis, Christian A; Silikas, Nikolaos; Neto, Castro A H; Rosa, Vinicius Graphene nanocoating provides superb long-lasting corrosion protection to titanium alloy Journal Article DENTAL MATERIALS, 37 (10), pp. 1553-1560, 2021, ISSN: 0109-5641. @article{ISI:000703997600010, title = {Graphene nanocoating provides superb long-lasting corrosion protection to titanium alloy}, author = {Ritika Malhotra and Yingmei Han and Christian A Nijhuis and Nikolaos Silikas and Castro A H Neto and Vinicius Rosa}, doi = {10.1016/j.dental.2021.08.004}, times_cited = {0}, issn = {0109-5641}, year = {2021}, date = {2021-09-24}, journal = {DENTAL MATERIALS}, volume = {37}, number = {10}, pages = {1553-1560}, publisher = {ELSEVIER SCI LTD}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND}, abstract = {Objective. The presence of metallic species around failed implants raises concerns about the stability of titanium alloy (Ti-6Al-4V). Graphene nanocoating on titanium alloy (GN) has promising anti-corrosion properties, but its long-term protective potential and structural stability remains unknown. The objective was to determine GN's anti-corrosion potential and stability over time. Methods. GN and uncoated titanium alloy (Control) were challenged with a highly acidic fluorinated corrosive medium (pH 2.0) for up to 240 days. The samples were periodically tested using potentiodynamic polarization curves, electrochemical impedance spectroscopy and inductively coupled plasma-atomic emission spectroscopy (elemental release). The integrity of samples was determined using Raman spectroscopy, X-ray photoelectron spectroscopy, atomic force microscopy and scanning electron microscopy. Statistical analyses were performed with one-sample t-test, paired t-test and one-way ANOVA with Tukey post-hoc test with a pre-set significance level of 5%. Results. There was negligible corrosion and elemental loss on GN. After 240 days of corrosion challenge, the corrosion rate and roughness increased by two and twelve times for the Control whereas remained unchanged for GN. The nanocoating presented remarkably high structural integrity and coverage area (>98%) at all time points tested. Significance. Graphene nanocoating protects titanium alloy from corrosion and dissolution over a long period while maintaining high structural integrity. This coating has promising potential for persistent protection of titanium and potentially other metallic alloys against corrosion. (c) 2021 The Author(s). Published by Elsevier Inc. on behalf of The Academy of Dental Materials. This is an open access article under the CC BY-NC-ND license (http:// creativecommons.org/licenses/by-nc-nd/4.0/).}, keywords = {}, pubstate = {published}, tppubtype = {article} } Objective. The presence of metallic species around failed implants raises concerns about the stability of titanium alloy (Ti-6Al-4V). Graphene nanocoating on titanium alloy (GN) has promising anti-corrosion properties, but its long-term protective potential and structural stability remains unknown. The objective was to determine GN's anti-corrosion potential and stability over time. Methods. GN and uncoated titanium alloy (Control) were challenged with a highly acidic fluorinated corrosive medium (pH 2.0) for up to 240 days. The samples were periodically tested using potentiodynamic polarization curves, electrochemical impedance spectroscopy and inductively coupled plasma-atomic emission spectroscopy (elemental release). The integrity of samples was determined using Raman spectroscopy, X-ray photoelectron spectroscopy, atomic force microscopy and scanning electron microscopy. Statistical analyses were performed with one-sample t-test, paired t-test and one-way ANOVA with Tukey post-hoc test with a pre-set significance level of 5%. Results. There was negligible corrosion and elemental loss on GN. After 240 days of corrosion challenge, the corrosion rate and roughness increased by two and twelve times for the Control whereas remained unchanged for GN. The nanocoating presented remarkably high structural integrity and coverage area (>98%) at all time points tested. Significance. Graphene nanocoating protects titanium alloy from corrosion and dissolution over a long period while maintaining high structural integrity. This coating has promising potential for persistent protection of titanium and potentially other metallic alloys against corrosion. (c) 2021 The Author(s). Published by Elsevier Inc. on behalf of The Academy of Dental Materials. This is an open access article under the CC BY-NC-ND license (http:// creativecommons.org/licenses/by-nc-nd/4.0/). |
Agarwalla, Shruti Vidhawan; Ellepola, Kassapa; Silikas, Nikolaos; Neto, Castro A H; Seneviratne, Chaminda Jayampath; Rosa, Vinicius Persistent inhibition of Candida albicans biofilm and hyphae growth on titanium by graphene nanocoating Journal Article DENTAL MATERIALS, 37 (2), pp. 370-377, 2021, ISSN: 0109-5641. @article{ISI:000613561700021, title = {Persistent inhibition of \textit{Candida albicans} biofilm and hyphae growth on titanium by graphene nanocoating}, author = {Shruti Vidhawan Agarwalla and Kassapa Ellepola and Nikolaos Silikas and Castro A H Neto and Chaminda Jayampath Seneviratne and Vinicius Rosa}, doi = {10.1016/j.dental.2020.11.028}, times_cited = {0}, issn = {0109-5641}, year = {2021}, date = {2021-01-21}, journal = {DENTAL MATERIALS}, volume = {37}, number = {2}, pages = {370-377}, publisher = {ELSEVIER SCI LTD}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND}, abstract = {Objectives. Candida albicanscolonizes biomaterial surfaces and are highly resistant to therapeutics. Graphene nanocoating on titanium compromises initial biofilm formation. However, its sustained antibiofilm potential is unknown. The objective of this study was to investigate the potential of graphene nanocoating to decrease long-term fungal biofilm development and hyphae growth on titanium.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Objectives. Candida albicanscolonizes biomaterial surfaces and are highly resistant to therapeutics. Graphene nanocoating on titanium compromises initial biofilm formation. However, its sustained antibiofilm potential is unknown. The objective of this study was to investigate the potential of graphene nanocoating to decrease long-term fungal biofilm development and hyphae growth on titanium. |
2020 |
Dubey, Nileshkumar; Morin, Julien Luc Paul; Luong-Van, Emma Kim; Agarwalla, Shruti Vidhawan; Silikas, Nikolaos; Neto, Castro A H; Rosa, Vinicius Osteogenic potential of graphene coated titanium is independent of transfer technique Journal Article MATERIALIA , 9 , 2020, ISSN: 2589-1529. @article{ISI:000537621200094, title = {Osteogenic potential of graphene coated titanium is independent of transfer technique }, author = {Nileshkumar Dubey and Julien Luc Paul Morin and Emma Kim Luong-Van and Shruti Vidhawan Agarwalla and Nikolaos Silikas and Castro A H Neto and Vinicius Rosa}, doi = {10.1016/j.mtla.2020.100604}, times_cited = {9}, issn = {2589-1529}, year = {2020}, date = {2020-03-01}, journal = {MATERIALIA }, volume = {9}, publisher = {ELSEVIER SCI LTD }, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND }, abstract = {The rapid integration of titanium implants into native bone remains a challenge in orthopedics and dental implantology. Several surface modifications have been attempted, but with limited success. Graphene coating has emerged as a candidate for shortening integration time due to its osteogenic potential. The wet transfer technique (WGp) is widely used to demonstrate graphene's osteogenic potential but it is laborious and time-consuming, hence compromising industrial scalability and market adoption. Moreover, this transfer method traps water between the coating and the target substrate, which can further deteriorate the coating and compromise its clinical translation even more. Alternatively, the dry transfer (DGp) method, based on the mechanized application of pressurized heat, allows graphene films to be transferred directly from a tape onto titanium in few minutes at a low cost. Here, we show that a single dry transfer procedure can coat >90% of titanium samples with graphene. Compared with uncoated titanium, DGp increased the expression of cellular adhesion and collagen-related genes, collagen production, and bone formation. Raman and atomic force microscopy showed that cellular structures and stiffness were similar to those observed on uncoated titanium and X-ray powder diffraction confirmed that DGp favors the early formation of octacalcium phosphate. The results demonstrating the potential of DGp were similar to WGp, confirming that the changes in transfer procedures performed to improve the likelihood of industrial scalability and clinical translation do not compromise the osteogenic potential of the graphene coating on titanium. }, keywords = {}, pubstate = {published}, tppubtype = {article} } The rapid integration of titanium implants into native bone remains a challenge in orthopedics and dental implantology. Several surface modifications have been attempted, but with limited success. Graphene coating has emerged as a candidate for shortening integration time due to its osteogenic potential. The wet transfer technique (WGp) is widely used to demonstrate graphene's osteogenic potential but it is laborious and time-consuming, hence compromising industrial scalability and market adoption. Moreover, this transfer method traps water between the coating and the target substrate, which can further deteriorate the coating and compromise its clinical translation even more. Alternatively, the dry transfer (DGp) method, based on the mechanized application of pressurized heat, allows graphene films to be transferred directly from a tape onto titanium in few minutes at a low cost. Here, we show that a single dry transfer procedure can coat >90% of titanium samples with graphene. Compared with uncoated titanium, DGp increased the expression of cellular adhesion and collagen-related genes, collagen production, and bone formation. Raman and atomic force microscopy showed that cellular structures and stiffness were similar to those observed on uncoated titanium and X-ray powder diffraction confirmed that DGp favors the early formation of octacalcium phosphate. The results demonstrating the potential of DGp were similar to WGp, confirming that the changes in transfer procedures performed to improve the likelihood of industrial scalability and clinical translation do not compromise the osteogenic potential of the graphene coating on titanium. |
Medeiros, Gabriela S; Munoz, Pablo A R; de Oliveira, Camila F P; da Silva, Laura C E; Malhotra, Ritika; Goncalves, Maria C; Rosa, Vinicius; Fechine, Guilhermino J M Polymer Nanocomposites Based on Poly(ε-caprolactone), Hydroxyapatite and Graphene Oxide Journal Article JOURNAL OF POLYMERS AND THE ENVIRONMENT, 28 (1), pp. 331-342, 2020, ISSN: 1566-2543. @article{ISI:000511994500027, title = {Polymer Nanocomposites Based on Poly(ε-caprolactone), Hydroxyapatite and Graphene Oxide}, author = {Gabriela S Medeiros and Pablo A R Munoz and Camila F P de Oliveira and Laura C E da Silva and Ritika Malhotra and Maria C Goncalves and Vinicius Rosa and Guilhermino J M Fechine}, doi = {10.1007/s10924-019-01613-w}, times_cited = {0}, issn = {1566-2543}, year = {2020}, date = {2020-01-01}, journal = {JOURNAL OF POLYMERS AND THE ENVIRONMENT}, volume = {28}, number = {1}, pages = {331-342}, publisher = {SPRINGER}, address = {ONE NEW YORK PLAZA, SUITE 4600, NEW YORK, NY, UNITED STATES}, abstract = {Standard and hybrid polymer nanocomposites based on poly(e-caprolactone) (PCL), hydroxyapatite (HAp) and graphene oxide (GO). The GO synthetized here is made up of multilayer graphene oxide (mGO), in which up to five layers are stacked and lateral size around of 1 mu m. The nanocomposites (PCL/Hap, PCL/mGO and PCL/HAp/mGO) were prepared by melt mixing in a twin-screw extruder and characterized by mechanical test, transmission electron microscopy (TEM), infrared spectroscopy (FTIR), X-ray diffraction (XRD), contact angle (CA), surface zeta potential by streaming and cell proliferation. The HAp content was maintained at 20% (w/w) while mGO was used at three levels of content (0.05, 0.1, and 0.3 w/w). In terms of bulk properties, the presence of mGO even in very low content (0.05 to 0.3%) was very effective in order to increase mechanical properties of PCL (stress and strain at beak and tenacity) while HAp tends to decrease them. When the two fillers are inserted mGO act to recover the properties lost by the presence of HAp. TEM images showed single GO sheets very well dispersed alone or combined with HAp. For surface properties, significant changes have been achieved by the presence of mGO, HAp and mGO/HAp. The water contact angle drops to values below 90 degrees for all nanocomposites making the material hydrophilic, but again by the presence of only 0.05% of mGO it was reached easily. Surface xi-potential for all nanocomposite was lower than neat PCL. As a consequence of surface modifications improvements in cell proliferation ability could be also observed. All modification by the presence of GO point out these materials as excellent candidates to resorbable suture, drug delivery system, and bone graft substitutes.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Standard and hybrid polymer nanocomposites based on poly(e-caprolactone) (PCL), hydroxyapatite (HAp) and graphene oxide (GO). The GO synthetized here is made up of multilayer graphene oxide (mGO), in which up to five layers are stacked and lateral size around of 1 mu m. The nanocomposites (PCL/Hap, PCL/mGO and PCL/HAp/mGO) were prepared by melt mixing in a twin-screw extruder and characterized by mechanical test, transmission electron microscopy (TEM), infrared spectroscopy (FTIR), X-ray diffraction (XRD), contact angle (CA), surface zeta potential by streaming and cell proliferation. The HAp content was maintained at 20% (w/w) while mGO was used at three levels of content (0.05, 0.1, and 0.3 w/w). In terms of bulk properties, the presence of mGO even in very low content (0.05 to 0.3%) was very effective in order to increase mechanical properties of PCL (stress and strain at beak and tenacity) while HAp tends to decrease them. When the two fillers are inserted mGO act to recover the properties lost by the presence of HAp. TEM images showed single GO sheets very well dispersed alone or combined with HAp. For surface properties, significant changes have been achieved by the presence of mGO, HAp and mGO/HAp. The water contact angle drops to values below 90 degrees for all nanocomposites making the material hydrophilic, but again by the presence of only 0.05% of mGO it was reached easily. Surface xi-potential for all nanocomposite was lower than neat PCL. As a consequence of surface modifications improvements in cell proliferation ability could be also observed. All modification by the presence of GO point out these materials as excellent candidates to resorbable suture, drug delivery system, and bone graft substitutes. |
2019 |
Agarwalla, Shruti Vidhawan; Malhotra, Ritika; Rosa, Vinicius Translucency, hardness and strength parameters of PMMA resin containing graphene-like material for CAD/CAM restorations Journal Article JOURNAL OF THE MECHANICAL BEHAVIOR OF BIOMEDICAL MATERIALS, 100 , 2019, ISSN: 1751-6161. @article{ISI:000496832200018, title = {Translucency, hardness and strength parameters of PMMA resin containing graphene-like material for CAD/CAM restorations}, author = {Shruti Vidhawan Agarwalla and Ritika Malhotra and Vinicius Rosa}, doi = {10.1016/j.jmbbm.2019.103388}, times_cited = {0}, issn = {1751-6161}, year = {2019}, date = {2019-12-01}, journal = {JOURNAL OF THE MECHANICAL BEHAVIOR OF BIOMEDICAL MATERIALS}, volume = {100}, publisher = {ELSEVIER}, address = {RADARWEG 29, 1043 NX AMSTERDAM, NETHERLANDS}, abstract = {CAD/CAM restorations can be produced from several ceramic and hybrid materials. The moderate mechanical properties of PMMA based resin have hindered its use for permanent restorations. Recently, a graphene reinforced PMMA namely G-CAM has been introduced for permanent CAD/CAM restorations. Although graphene family materials have been successfully used as a reinforcement phase in a variety of polymers, the properties and mechanical behavior of PMMA resin containing graphene-like materials remain unknown. Herein, we have evaluated the translucency, hardness and strength parameters (flexural strength, Weibull modulus and characteristic strength) of G-CAM Al (GA1) and G-CAM B2 (GB2) and benchmarked it against a unmodified PMMA resin (PM), two polymer/ceramic hybrid materials [Vita Enamic WE) and Lava Ultimate (LU)] and one ceramic (e.max, EX) for CAD/CAM restorations. The trends for the translucency parameter were similar for all materials at all thickness tested. The hardness for GA1, GB2 and PM were significantly lower than VE, LU and EX. The biaxial flexural strengths of GA1, GB2, PM and VE were approximately 150 MPa but significantly lower than LU and EX (201 and 313 MPa). All materials presented Weibull modulus higher than 10, except EX (m = 8) The stresses required to fracture 5% and 63.2% of specimens (sigma(5)% and sigma(0)) were similar for GA1, GB2, PM and VE but significantly lower than LU and EX. Overall, the PMMA modified by graphene-like materials presented properties comparable with unmodified PM and VE.}, keywords = {}, pubstate = {published}, tppubtype = {article} } CAD/CAM restorations can be produced from several ceramic and hybrid materials. The moderate mechanical properties of PMMA based resin have hindered its use for permanent restorations. Recently, a graphene reinforced PMMA namely G-CAM has been introduced for permanent CAD/CAM restorations. Although graphene family materials have been successfully used as a reinforcement phase in a variety of polymers, the properties and mechanical behavior of PMMA resin containing graphene-like materials remain unknown. Herein, we have evaluated the translucency, hardness and strength parameters (flexural strength, Weibull modulus and characteristic strength) of G-CAM Al (GA1) and G-CAM B2 (GB2) and benchmarked it against a unmodified PMMA resin (PM), two polymer/ceramic hybrid materials [Vita Enamic WE) and Lava Ultimate (LU)] and one ceramic (e.max, EX) for CAD/CAM restorations. The trends for the translucency parameter were similar for all materials at all thickness tested. The hardness for GA1, GB2 and PM were significantly lower than VE, LU and EX. The biaxial flexural strengths of GA1, GB2, PM and VE were approximately 150 MPa but significantly lower than LU and EX (201 and 313 MPa). All materials presented Weibull modulus higher than 10, except EX (m = 8) The stresses required to fracture 5% and 63.2% of specimens (sigma(5)% and sigma(0)) were similar for GA1, GB2, PM and VE but significantly lower than LU and EX. Overall, the PMMA modified by graphene-like materials presented properties comparable with unmodified PM and VE. |
Agarwalla, Shruti Vidhawan; Ellepola, Kassapa; da Costa, Mariana Caldeira Ferraz; Fechine, Guilhermino Jose Macedo; Morin, Julien Luc Paul; Neto, Castro A H; Seneviratne, Chaminda Jayampath; Rosa, Vinicius Hydrophobicity of graphene as a driving force for inhibiting biofilm formation of pathogenic bacteria and fungi Journal Article DENTAL MATERIALS, 35 (3), pp. 403-413, 2019, ISSN: 0109-5641. @article{ISI:000458793600002, title = {Hydrophobicity of graphene as a driving force for inhibiting biofilm formation of pathogenic bacteria and fungi}, author = {Shruti Vidhawan Agarwalla and Kassapa Ellepola and Mariana Caldeira Ferraz da Costa and Guilhermino Jose Macedo Fechine and Julien Luc Paul Morin and Castro A H Neto and Chaminda Jayampath Seneviratne and Vinicius Rosa}, doi = {10.1016/j.dental.2018.09.016}, times_cited = {0}, issn = {0109-5641}, year = {2019}, date = {2019-03-01}, journal = {DENTAL MATERIALS}, volume = {35}, number = {3}, pages = {403-413}, publisher = {ELSEVIER SCI LTD}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND}, abstract = {Objective. To evaluate the surface and wettability characteristics and the microbial biofilm interaction of graphene coating on titanium.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Objective. To evaluate the surface and wettability characteristics and the microbial biofilm interaction of graphene coating on titanium. |
Xie, Han; Cao, Tong; Franco-Obregon, Alfredo; Rosa, Vinicius Graphene-Induced Osteogenic Differentiation Is Mediated by the Integrin/FAK Axis Journal Article INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES, 20 (3), 2019, ISSN: 1422-0067. @article{ISI:000462412500118, title = {Graphene-Induced Osteogenic Differentiation Is Mediated by the Integrin/FAK Axis}, author = {Han Xie and Tong Cao and Alfredo Franco-Obregon and Vinicius Rosa}, doi = {10.3390/ijms20030574}, times_cited = {0}, issn = {1422-0067}, year = {2019}, date = {2019-02-01}, journal = {INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES}, volume = {20}, number = {3}, publisher = {MDPI}, address = {ST ALBAN-ANLAGE 66, CH-4052 BASEL, SWITZERLAND}, abstract = {Graphene is capable of promoting osteogenesis without chemical induction. Nevertheless, the underlying mechanism(s) remain largely unknown. The objectives here were: (i) to assess whether graphene scaffolds are capable of supporting osteogenesis in vivo and; (ii) to ascertain the participation of the integrin/FAK mechanotransduction axis during the osteogenic differentiation induced by graphene. MSC-impregnated graphene scaffolds (n = 6) were implanted into immunocompromised mice (28 days). Alternatively, MSCs were seeded onto PDMS substrates (modulus of elasticity = 130, 830 and 1300 kPa) coated with a single monomolecular layer of graphene and cultured in basal medium (10 days). The ensuing expressions of FAK-p397, integrin, ROCK1, F-actin, Smad p1/5, RUNX2, OCN and OPN were evaluated by Western blot (n = 3). As controls, MSCs were plated onto uncoated PDMS in the presence of mechanotransduction inhibitors (echistatin, Y27632 and DMH1). MSC-impregnated graphene scaffolds exhibited positive immunoexpression of bone-related markers (RUNX2 and OPN) without the assistance of osteogenic inducers. In vitro, regardless of the stiffness of the underlying PDMS substrate, MSCs seeded onto graphene-coated PDMS substrates demonstrated higher expressions of all tested osteogenic and integrin/FAK proteins tested compared to MSCs seeded onto PDMS alone. Hence, graphene promotes osteogenesis via the activation of the mechanosensitive integrin/FAK axis.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Graphene is capable of promoting osteogenesis without chemical induction. Nevertheless, the underlying mechanism(s) remain largely unknown. The objectives here were: (i) to assess whether graphene scaffolds are capable of supporting osteogenesis in vivo and; (ii) to ascertain the participation of the integrin/FAK mechanotransduction axis during the osteogenic differentiation induced by graphene. MSC-impregnated graphene scaffolds (n = 6) were implanted into immunocompromised mice (28 days). Alternatively, MSCs were seeded onto PDMS substrates (modulus of elasticity = 130, 830 and 1300 kPa) coated with a single monomolecular layer of graphene and cultured in basal medium (10 days). The ensuing expressions of FAK-p397, integrin, ROCK1, F-actin, Smad p1/5, RUNX2, OCN and OPN were evaluated by Western blot (n = 3). As controls, MSCs were plated onto uncoated PDMS in the presence of mechanotransduction inhibitors (echistatin, Y27632 and DMH1). MSC-impregnated graphene scaffolds exhibited positive immunoexpression of bone-related markers (RUNX2 and OPN) without the assistance of osteogenic inducers. In vitro, regardless of the stiffness of the underlying PDMS substrate, MSCs seeded onto graphene-coated PDMS substrates demonstrated higher expressions of all tested osteogenic and integrin/FAK proteins tested compared to MSCs seeded onto PDMS alone. Hence, graphene promotes osteogenesis via the activation of the mechanosensitive integrin/FAK axis. |
2018 |
Dubey, Nileshkumar; Ellepola, Kassapa; Decroix, Fanny E D; Morin, Julien L P; Neto, Ah Castro; Seneviratne, Chaminda J; Rosa, Vinicius Graphene onto medical grade titanium: an atom-thick multimodal coating that promotes osteoblast maturation and inhibits biofilm formation from distinct species Journal Article 14 NANOTOXICOLOGY, 12 (4), pp. 274-289, 2018, ISSN: 1743-5390. @article{ISI:000430425800001, title = {Graphene onto medical grade titanium: an atom-thick multimodal coating that promotes osteoblast maturation and inhibits biofilm formation from distinct species}, author = {Nileshkumar Dubey and Kassapa Ellepola and Fanny E D Decroix and Julien L P Morin and Ah Castro Neto and Chaminda J Seneviratne and Vinicius Rosa}, doi = {10.1080/17435390.2018.1434911}, times_cited = {14}, issn = {1743-5390}, year = {2018}, date = {2018-01-01}, journal = {NANOTOXICOLOGY}, volume = {12}, number = {4}, pages = {274-289}, publisher = {TAYLOR & FRANCIS LTD}, address = {2-4 PARK SQUARE, MILTON PARK, ABINGDON OR14 4RN, OXON, ENGLAND}, abstract = {The time needed for the osseointegration of titanium implants is deemed too long. Moreover, the bacterial colonization of their surfaces is a major cause of failure. Graphene can overcome these issues but its wet transfer onto substrates employs hazardous chemicals limiting the clinical applications. Alternatively, dry transfer technique has been developed, but the biological properties of this technique remain unexplored. Here, a dry transfer technique based on a hot-pressing method allowed to coat titanium substrates with high-quality graphene and coverage area >90% with a single transfer. The graphene-coated titanium is cytocompatible, did not induce cell membrane damage, induced human osteoblast maturation (gene and protein level), and increased the deposition of mineralized matrix compared to titanium alone. Moreover, graphene decreased the formation of biofilms from Streptococcus mutans, Enterococcus faecalis and even from whole saliva on titanium without killing the bacteria. These findings confirm that coating of titanium with graphene via a dry transfer technique is a promising strategy to improve osseointegration and prevent biofilm formation on implants and devices.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The time needed for the osseointegration of titanium implants is deemed too long. Moreover, the bacterial colonization of their surfaces is a major cause of failure. Graphene can overcome these issues but its wet transfer onto substrates employs hazardous chemicals limiting the clinical applications. Alternatively, dry transfer technique has been developed, but the biological properties of this technique remain unexplored. Here, a dry transfer technique based on a hot-pressing method allowed to coat titanium substrates with high-quality graphene and coverage area >90% with a single transfer. The graphene-coated titanium is cytocompatible, did not induce cell membrane damage, induced human osteoblast maturation (gene and protein level), and increased the deposition of mineralized matrix compared to titanium alone. Moreover, graphene decreased the formation of biofilms from Streptococcus mutans, Enterococcus faecalis and even from whole saliva on titanium without killing the bacteria. These findings confirm that coating of titanium with graphene via a dry transfer technique is a promising strategy to improve osseointegration and prevent biofilm formation on implants and devices. |
2017 |
Xie, Han; Cao, Tong; Rodriguez-Lozano, Francisco Javier; Luong-Van, Emma Kim; Rosa, Vinicius Graphene for the development of the next-generation of biocomposites for dental and medical applications Journal Article DENTAL MATERIALS, 33 (7), pp. 765-774, 2017, ISSN: 0109-5641. @article{ISI:000405348700004, title = {Graphene for the development of the next-generation of biocomposites for dental and medical applications}, author = {Han Xie and Tong Cao and Francisco Javier Rodriguez-Lozano and Emma Kim Luong-Van and Vinicius Rosa}, doi = {10.1016/j.dental.2017.04.008}, times_cited = {0}, issn = {0109-5641}, year = {2017}, date = {2017-07-01}, journal = {DENTAL MATERIALS}, volume = {33}, number = {7}, pages = {765-774}, publisher = {ELSEVIER SCI LTD}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND}, abstract = {Objective: Graphene and its derivatives, graphene oxide (GO) and reduced graphene oxide (rGO), are 2D carbon-based materials with remarkable physical, chemical and biological properties. Graphene sheets have high specific surface area and mechanical strength. Moreover, they have been shown to influence the differentiation of stem cells and to improve properties of biomaterials.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Objective: Graphene and its derivatives, graphene oxide (GO) and reduced graphene oxide (rGO), are 2D carbon-based materials with remarkable physical, chemical and biological properties. Graphene sheets have high specific surface area and mechanical strength. Moreover, they have been shown to influence the differentiation of stem cells and to improve properties of biomaterials. |
Dubey, Nileshkumar; Rajan, Sneha Sundar; Bello, Yuri Dal; Min, Kyung-San; Rosa, Vinicius Graphene Nanosheets to Improve Physico-Mechanical Properties of Bioactive Calcium Silicate Cements Journal Article MATERIALS, 10 (6), 2017, ISSN: 1996-1944. @article{ISI:000404415000040, title = {Graphene Nanosheets to Improve Physico-Mechanical Properties of Bioactive Calcium Silicate Cements}, author = {Nileshkumar Dubey and Sneha Sundar Rajan and Yuri Dal Bello and Kyung-San Min and Vinicius Rosa}, doi = {10.3390/ma10060606}, times_cited = {1}, issn = {1996-1944}, year = {2017}, date = {2017-06-01}, journal = {MATERIALS}, volume = {10}, number = {6}, publisher = {MDPI}, address = {ST ALBAN-ANLAGE 66, CH-4052 BASEL, SWITZERLAND}, abstract = {Bioactive calcium silicate cements are widely used to induce mineralization, to cement prosthetic parts, in the management of tooth perforations, and other areas. Nonetheless, they can present clinical disadvantages, such as long setting time and modest physico-mechanical properties. The objective of this work was to evaluate the potential of graphene nanosheets (GNS) to improve two bioactive cements. GNS were obtained via reduction of graphite oxide. GNS were mixed (1, 3, 5, and 7 wt %) with Biodentine (BIO) and Endocem Zr (ECZ), and the effects on setting time, hardness, push-out strength, pH profile, cell proliferation, and mineralization were evaluated. Statistics were performed with two-way ANOVA and Tukey test ( = 0.05). GNS has not interfered in the composition of the set cements as confirmed by Raman, FT-IR and XRD. GNS (1 and 3 wt %) shortened the setting time, increased hardness of both materials but decreased significantly the push-out strength of ECZ. pH was not affected but 1 wt % and 7 wt % to ECZ and 5 wt % to BIO increased the mineralization compared to the controls. In summary, GNS may be an alternative to improve the physico-mechanical properties and bioactivity of cements. Nonetheless, the use of GNS may not be advised for all materials when effective bonding is a concern.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Bioactive calcium silicate cements are widely used to induce mineralization, to cement prosthetic parts, in the management of tooth perforations, and other areas. Nonetheless, they can present clinical disadvantages, such as long setting time and modest physico-mechanical properties. The objective of this work was to evaluate the potential of graphene nanosheets (GNS) to improve two bioactive cements. GNS were obtained via reduction of graphite oxide. GNS were mixed (1, 3, 5, and 7 wt %) with Biodentine (BIO) and Endocem Zr (ECZ), and the effects on setting time, hardness, push-out strength, pH profile, cell proliferation, and mineralization were evaluated. Statistics were performed with two-way ANOVA and Tukey test ( = 0.05). GNS has not interfered in the composition of the set cements as confirmed by Raman, FT-IR and XRD. GNS (1 and 3 wt %) shortened the setting time, increased hardness of both materials but decreased significantly the push-out strength of ECZ. pH was not affected but 1 wt % and 7 wt % to ECZ and 5 wt % to BIO increased the mineralization compared to the controls. In summary, GNS may be an alternative to improve the physico-mechanical properties and bioactivity of cements. Nonetheless, the use of GNS may not be advised for all materials when effective bonding is a concern. |
Morin, J L P; Dubey, N; Decroix, F E D; Luong-Van, E K; Neto, Castro A H; Rosa, V Graphene transfer to 3-dimensional surfaces: a vacuum-assisted dry transfer method Journal Article 2D MATERIALS, 4 (2), 2017, ISSN: 2053-1583. @article{ISI:000398424400007, title = {Graphene transfer to 3-dimensional surfaces: a vacuum-assisted dry transfer method}, author = {J L P Morin and N Dubey and F E D Decroix and E K Luong-Van and Castro A H Neto and V Rosa}, doi = {10.1088/2053-1583/aa6530}, times_cited = {0}, issn = {2053-1583}, year = {2017}, date = {2017-06-01}, journal = {2D MATERIALS}, volume = {4}, number = {2}, publisher = {IOP PUBLISHING LTD}, address = {TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND}, abstract = {Chemical vapour deposition (CVD) grown graphene presents an efficient synthetic route for large-scale graphene production, however, current transfer methods are focused on transferring graphene onto planar substrates. Here, we describe a method to uniformly transfer CVD-grown graphene onto 3D objects with high shape complexity. Due to its promises as a coating for medical applications, we investigated graphene transfer onto commercially available titanium implants with different geometries using a vacuum-assisted dry transfer method. A self-standing graphene-polymer tape is obtained by spin coating of a silicone polymer on the graphene, followed by the addition of a support layer, and the electrochemical delimitation of the growth substrate. The tape is then wrapped around the object and placed into a mould to conform to the surface. Using a pressure differential provided via partial vacuum, a uniform force is applied to the surface. Graphene characteristics are assessed by Raman spectroscopy and AFM. 74% and 95% coverage yields are obtained after a single transfer and double transfer respectively, with an observed increase in the number of graphene layers and an overall decrease in defect contributions. In vitro cell assays demonstrate that the coating is non-cytotoxic enabling further exploration of this method for medical applications.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Chemical vapour deposition (CVD) grown graphene presents an efficient synthetic route for large-scale graphene production, however, current transfer methods are focused on transferring graphene onto planar substrates. Here, we describe a method to uniformly transfer CVD-grown graphene onto 3D objects with high shape complexity. Due to its promises as a coating for medical applications, we investigated graphene transfer onto commercially available titanium implants with different geometries using a vacuum-assisted dry transfer method. A self-standing graphene-polymer tape is obtained by spin coating of a silicone polymer on the graphene, followed by the addition of a support layer, and the electrochemical delimitation of the growth substrate. The tape is then wrapped around the object and placed into a mould to conform to the surface. Using a pressure differential provided via partial vacuum, a uniform force is applied to the surface. Graphene characteristics are assessed by Raman spectroscopy and AFM. 74% and 95% coverage yields are obtained after a single transfer and double transfer respectively, with an observed increase in the number of graphene layers and an overall decrease in defect contributions. In vitro cell assays demonstrate that the coating is non-cytotoxic enabling further exploration of this method for medical applications. |