Lim Chwee Teck
Degree: PhD
Position: Professor
Affiliation: NUS – Department of Mechanical Engineering
Research Type: Experiment
Office: EA-05-10
Email: ctlim@nus.edu.sg
Contact: (65) 6516 7801
Website: http://www.physics.nus.edu.sg/~ondl/
Research Interests:
Biomedical Applications of 2D Materials
Flexible and Wearable Devices
Nanomechanical Characterisation
CA2DM Publications:
2024 |
Ronceray, Nathan; Spina, Massimo; Chou, Vanessa Hui Yin; Lim, Chwee Teck; Geim, Andre K; Garaj, Slaven Elastocapillarity-driven 2D nano-switches enable zeptoliter-scale liquid encapsulation Journal Article NATURE COMMUNICATIONS, 15 (1), 2024. @article{ISI:001158425400020, title = {Elastocapillarity-driven 2D nano-switches enable zeptoliter-scale liquid encapsulation}, author = {Nathan Ronceray and Massimo Spina and Vanessa Hui Yin Chou and Chwee Teck Lim and Andre K Geim and Slaven Garaj}, doi = {10.1038/s41467-023-44200-3}, times_cited = {0}, year = {2024}, date = {2024-01-02}, journal = {NATURE COMMUNICATIONS}, volume = {15}, number = {1}, publisher = {NATURE PORTFOLIO}, address = {HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY}, abstract = {Biological nanostructures change their shape and function in response to external stimuli, and significant efforts have been made to design artificial biomimicking devices operating on similar principles. In this work we demonstrate a programmable nanofluidic switch, driven by elastocapillarity, and based on nanochannels built fromlayered two-dimensional nanomaterials possessing atomically smooth surfaces and exceptional mechanical properties. We explore operational modes of the nanoswitch and develop a theoretical framework to explain the phenomenon. By predicting the switchingreversibility phase diagram-based on material, interfacial and wetting properties, as well as the geometry of the nanofluidic circuit-we rationally design switchable nano-capsules capable of enclosing zeptoliter volumes of liquid, as small as the volumes enclosed in viruses. The nanoswitch will find useful application as an active element in integrated nanofluidic circuitry and could be used to explore nanoconfined chemistry and biochemistry, or be incorporated into shape-programmable materials.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Biological nanostructures change their shape and function in response to external stimuli, and significant efforts have been made to design artificial biomimicking devices operating on similar principles. In this work we demonstrate a programmable nanofluidic switch, driven by elastocapillarity, and based on nanochannels built fromlayered two-dimensional nanomaterials possessing atomically smooth surfaces and exceptional mechanical properties. We explore operational modes of the nanoswitch and develop a theoretical framework to explain the phenomenon. By predicting the switchingreversibility phase diagram-based on material, interfacial and wetting properties, as well as the geometry of the nanofluidic circuit-we rationally design switchable nano-capsules capable of enclosing zeptoliter volumes of liquid, as small as the volumes enclosed in viruses. The nanoswitch will find useful application as an active element in integrated nanofluidic circuitry and could be used to explore nanoconfined chemistry and biochemistry, or be incorporated into shape-programmable materials. |
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. |
2019 |
Tan, Eveline; Li, Ban Lin; Ariga, Katsuhiko; Lim, Chwee-Teck; Garaj, Slaven; Leong, David Tai Toxicity of Two-Dimensional Layered Materials and Their Heterostructures Journal Article 44 BIOCONJUGATE CHEMISTRY, 30 (9), pp. 2287-2299, 2019, ISSN: 1043-1802. @article{ISI:000487180000003, title = {Toxicity of Two-Dimensional Layered Materials and Their Heterostructures}, author = {Eveline Tan and Ban Lin Li and Katsuhiko Ariga and Chwee-Teck Lim and Slaven Garaj and David Tai Leong}, doi = {10.1021/acs.bioconjchem.9b00502}, times_cited = {44}, issn = {1043-1802}, year = {2019}, date = {2019-09-01}, journal = {BIOCONJUGATE CHEMISTRY}, volume = {30}, number = {9}, pages = {2287-2299}, publisher = {AMER CHEMICAL SOC}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {Two-dimensional layered materials (2D LMs) are taking the scientific world by storm. Graphene epitomizes 2D LMs with many interesting properties and corresponding applications. Following the footsteps of graphene, many other types of 2D LMs such as transition metal dichalcogenides, black phosphorus, and graphitic-phase C3N4 nanosheets are emerging to be equally interesting as graphene and its derivatives. Some of these applications such as nanomedicine do have a high probability of human exposure. This review focuses on the biological and toxicity effects of 2D LMs and their associated mechanisms linking their chemistries to their biological end points. This review aims to help researchers to predict and mitigate any toxic effects. With understanding, redesign of newer and safer 2D LMs becomes possible.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Two-dimensional layered materials (2D LMs) are taking the scientific world by storm. Graphene epitomizes 2D LMs with many interesting properties and corresponding applications. Following the footsteps of graphene, many other types of 2D LMs such as transition metal dichalcogenides, black phosphorus, and graphitic-phase C3N4 nanosheets are emerging to be equally interesting as graphene and its derivatives. Some of these applications such as nanomedicine do have a high probability of human exposure. This review focuses on the biological and toxicity effects of 2D LMs and their associated mechanisms linking their chemistries to their biological end points. This review aims to help researchers to predict and mitigate any toxic effects. With understanding, redesign of newer and safer 2D LMs becomes possible. |
Ding, Xianguang; Peng, Fei; Zhou, Jun; Gong, Wenbin; Slaven, Garaj; Loh, Kian Ping; Lim, Chwee Teck; Leong, David Tai Defect engineered bioactive transition metals dichalcogenides quantum dots Journal Article NATURE COMMUNICATIONS, 10 , 2019, ISSN: 2041-1723. @article{ISI:000454757200006, title = {Defect engineered bioactive transition metals dichalcogenides quantum dots}, author = {Xianguang Ding and Fei Peng and Jun Zhou and Wenbin Gong and Garaj Slaven and Kian Ping Loh and Chwee Teck Lim and David Tai Leong}, doi = {10.1038/s41467-018-07835-1}, times_cited = {0}, issn = {2041-1723}, year = {2019}, date = {2019-01-03}, journal = {NATURE COMMUNICATIONS}, volume = {10}, publisher = {NATURE PUBLISHING GROUP}, address = {MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND}, abstract = {Transition metal dichalcogenide (TMD) quantum dots (QDs) are fundamentally interesting because of the stronger quantum size effect with decreased lateral dimensions relative to their larger 2D nanosheet counterparts. However, the preparation of a wide range of TMD QDs is still a continual challenge. Here we demonstrate a bottom-up strategy utilizing TM oxides or chlorides and chalcogen precursors to synthesize a small library of TMD QDs (MoS2, WS2, RuS2, MoTe2, MoSe2, WSe2 and RuSe2). The reaction reaches equilibrium almost instantaneously (similar to 10-20 s) with mild aqueous and room temperature conditions. Tunable defect engineering can be achieved within the same reactions by deviating the precursors' reaction stoichiometries from their fixed molecular stoichiometries. Using MoS2 QDs for proof-of-concept biomedical applications, we show that increasing sulfur defects enhanced oxidative stress generation, through the photodynamic effect, in cancer cells. This facile strategy will motivate future design of TMDs nanomaterials utilizing defect engineering for biomedical applications.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Transition metal dichalcogenide (TMD) quantum dots (QDs) are fundamentally interesting because of the stronger quantum size effect with decreased lateral dimensions relative to their larger 2D nanosheet counterparts. However, the preparation of a wide range of TMD QDs is still a continual challenge. Here we demonstrate a bottom-up strategy utilizing TM oxides or chlorides and chalcogen precursors to synthesize a small library of TMD QDs (MoS2, WS2, RuS2, MoTe2, MoSe2, WSe2 and RuSe2). The reaction reaches equilibrium almost instantaneously (similar to 10-20 s) with mild aqueous and room temperature conditions. Tunable defect engineering can be achieved within the same reactions by deviating the precursors' reaction stoichiometries from their fixed molecular stoichiometries. Using MoS2 QDs for proof-of-concept biomedical applications, we show that increasing sulfur defects enhanced oxidative stress generation, through the photodynamic effect, in cancer cells. This facile strategy will motivate future design of TMDs nanomaterials utilizing defect engineering for biomedical applications. |
2018 |
Kutty, Govindan R; Sreejith, Sivaramapanicker; Kong, Xianghua; He, Haiyong; Wang, Hong; Lin, Junhao; Suenaga, Kazu; Lim, Chwee Teck; Zhao, Yanli; Ji, Wei; Liu, Zheng A topologically substituted boron nitride hybrid aerogel for highly selective CO2 uptake Journal Article NANO RESEARCH, 11 (12), pp. 6325-6335, 2018, ISSN: 1998-0124. @article{ISI:000454367500019, title = {A topologically substituted boron nitride hybrid aerogel for highly selective CO_{2} uptake}, author = {Govindan R Kutty and Sivaramapanicker Sreejith and Xianghua Kong and Haiyong He and Hong Wang and Junhao Lin and Kazu Suenaga and Chwee Teck Lim and Yanli Zhao and Wei Ji and Zheng Liu}, doi = {10.1007/s12274-018-2156-z}, times_cited = {0}, issn = {1998-0124}, year = {2018}, date = {2018-12-01}, journal = {NANO RESEARCH}, volume = {11}, number = {12}, pages = {6325-6335}, publisher = {TSINGHUA UNIV PRESS}, address = {TSINGHUA UNIV, RM A703, XUEYAN BLDG, BEIJING, 100084, PEOPLES R CHINA}, abstract = {A topologically mediated synthesis of porous boron nitride aerogel has been experimentally and theoretically investigated for carbon dioxide (CO2) uptake. Replacement of the carbon atoms in a precursor aerogel of graphene oxide and carbon nanotubes was achieved using an elemental substitution reaction, to obtain a boron and nitrogen framework. The newly prepared BN aerogel possessed a specific surface area of 716.56 m(2)/g and exhibited an unprecedented twenty-fold increase in CO2 uptake over N-2, adsorbing 100 cc/g at 273 K and 80 cc/g in ambient conditions, as verified by adsorption isotherms via the multipoint Brunauer-Emmett-Teller (BET) method. Density functional theory calculations were performed to give hints on the mechanism of such high selectivity of CO2 over N-2 adsorption in BN aerogel, which may be due to the interaction between the intrinsic polar nature of B-N bonds and the high quadrupole moment of CO2 over N-2.}, keywords = {}, pubstate = {published}, tppubtype = {article} } A topologically mediated synthesis of porous boron nitride aerogel has been experimentally and theoretically investigated for carbon dioxide (CO2) uptake. Replacement of the carbon atoms in a precursor aerogel of graphene oxide and carbon nanotubes was achieved using an elemental substitution reaction, to obtain a boron and nitrogen framework. The newly prepared BN aerogel possessed a specific surface area of 716.56 m(2)/g and exhibited an unprecedented twenty-fold increase in CO2 uptake over N-2, adsorbing 100 cc/g at 273 K and 80 cc/g in ambient conditions, as verified by adsorption isotherms via the multipoint Brunauer-Emmett-Teller (BET) method. Density functional theory calculations were performed to give hints on the mechanism of such high selectivity of CO2 over N-2 adsorption in BN aerogel, which may be due to the interaction between the intrinsic polar nature of B-N bonds and the high quadrupole moment of CO2 over N-2. |
Edison, Eldho; Sreejith, Sivaramapanicker; Lim, Chwee Teck; Madhavi, Srinivasan Beyond intercalation based sodium-ion batteries: the role of alloying anodes, efficient sodiation mechanisms and recent progress Journal Article SUSTAINABLE ENERGY & FUELS, 2 (12), 2018, ISSN: 2398-4902. @article{ISI:000451078300002, title = {Beyond intercalation based sodium-ion batteries: the role of alloying anodes, efficient sodiation mechanisms and recent progress}, author = {Eldho Edison and Sivaramapanicker Sreejith and Chwee Teck Lim and Srinivasan Madhavi}, doi = {10.1039/c8se00381e}, times_cited = {0}, issn = {2398-4902}, year = {2018}, date = {2018-12-01}, journal = {SUSTAINABLE ENERGY & FUELS}, volume = {2}, number = {12}, publisher = {ROYAL SOC CHEMISTRY}, address = {THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND}, abstract = {Sodium-ion batteries (SIBs) have received renewed interest in recent years and are projected as an alternative to the existing lithium-ion battery (LIB) system. Research on SIBs is impelled by the low cost and abundant supply of sodium resources, the similar electrochemistry of SIBs and LIBs and the competing electrochemical performance achieved in recent years. Significant progress has been made in the development of alloying anodes for SIBs which offer high gravimetric and volumetric energy densities when compared to the conventional intercalation based anodes. Recent progress in the field of advanced operando and ex situ characterization techniques as well as theoretical computational studies has shed light on the sodiation mechanism of these alloying anodes. Herein, we review the recent developments in alloying anodes for SIBs. Primarily Sn, Sb, and P based alloying anodes are focused on and the progress in Bi, Ge and Si is also discussed. We focus on the sodiation mechanism of these alloying anodes, recently revealed by means of advanced experimental and computational tools, to enable the design of efficient strategies for enhanced electrochemical performance. We also discuss synthetic methodologies and novel approaches adopted for alloying anodes to mitigate the challenges faced during the (de)sodiation cycles. The future outlook and issues to be addressed to realize the practical implementation of alloying anodes are also discussed.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Sodium-ion batteries (SIBs) have received renewed interest in recent years and are projected as an alternative to the existing lithium-ion battery (LIB) system. Research on SIBs is impelled by the low cost and abundant supply of sodium resources, the similar electrochemistry of SIBs and LIBs and the competing electrochemical performance achieved in recent years. Significant progress has been made in the development of alloying anodes for SIBs which offer high gravimetric and volumetric energy densities when compared to the conventional intercalation based anodes. Recent progress in the field of advanced operando and ex situ characterization techniques as well as theoretical computational studies has shed light on the sodiation mechanism of these alloying anodes. Herein, we review the recent developments in alloying anodes for SIBs. Primarily Sn, Sb, and P based alloying anodes are focused on and the progress in Bi, Ge and Si is also discussed. We focus on the sodiation mechanism of these alloying anodes, recently revealed by means of advanced experimental and computational tools, to enable the design of efficient strategies for enhanced electrochemical performance. We also discuss synthetic methodologies and novel approaches adopted for alloying anodes to mitigate the challenges faced during the (de)sodiation cycles. The future outlook and issues to be addressed to realize the practical implementation of alloying anodes are also discussed. |
Edison, Eldho; Chaturvedi, Apoorva; Ren, Hao; Sreejith, Sivaramapanicker; Lim, Chwee Teck; Madhavi, Srinivasan Route of Irreversible Transformation in Layered Tin Thiophosphite and Enhanced Lithium Storage Performance Journal Article ACS APPLIED ENERGY MATERIALS, 1 (10), pp. 5772-5778, 2018, ISSN: 2574-0962. @article{ISI:000458706600073, title = {Route of Irreversible Transformation in Layered Tin Thiophosphite and Enhanced Lithium Storage Performance}, author = {Eldho Edison and Apoorva Chaturvedi and Hao Ren and Sivaramapanicker Sreejith and Chwee Teck Lim and Srinivasan Madhavi}, doi = {10.1021/acsaem.8b01357}, times_cited = {1}, issn = {2574-0962}, year = {2018}, date = {2018-10-01}, journal = {ACS APPLIED ENERGY MATERIALS}, volume = {1}, number = {10}, pages = {5772-5778}, publisher = {AMER CHEMICAL SOC}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {Novel materials with high lithium-storage capacities are indispensable to substantially increase the gravimetric and volumetric energy densities of lithium-ion batteries. In this context, metal thiophosphites (MTPs) possessing a layered structure are considered ideal candidates to serve as alkali-ion hosts. Herein, the lithium storage properties of layered tin thiophosphite (SnPS3) crystals have been investigated in coin-cell configuration. The results reveal that SnPS3 undergoes a conversion and alloying reaction to deliver high lithiation capacities. The SnPS3 anode delivered a significant lithiation capacity of similar to 800 mAh g(-1) at a specific current of 100 mA g(-1). Moreover, the layered structure was able to accommodate the volume changes upon (de)lithiation as evident from its excellent cycling stability. Additionally, the SnPS3 anode demonstrated excellent rate capability as well and delivered similar to 315 mAh g(-1) at a high specific current of 2 A g(-1) Furthermore, the lithium-storage mechanism was investigated through cyclic voltammetry and ex situ X-ray diffraction and Xray photoelectron spectroscopy studies. Studies of SnPS3 anode in a full cell configuration by coupling with commercial LiNi0.33Co0.33Mn0.33O2 cathode are also presented. The outstanding electrochemical performance demonstrated by the SnPS3 anode calls for further research into this novel class of metal thiophosphites for energy storage applications.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Novel materials with high lithium-storage capacities are indispensable to substantially increase the gravimetric and volumetric energy densities of lithium-ion batteries. In this context, metal thiophosphites (MTPs) possessing a layered structure are considered ideal candidates to serve as alkali-ion hosts. Herein, the lithium storage properties of layered tin thiophosphite (SnPS3) crystals have been investigated in coin-cell configuration. The results reveal that SnPS3 undergoes a conversion and alloying reaction to deliver high lithiation capacities. The SnPS3 anode delivered a significant lithiation capacity of similar to 800 mAh g(-1) at a specific current of 100 mA g(-1). Moreover, the layered structure was able to accommodate the volume changes upon (de)lithiation as evident from its excellent cycling stability. Additionally, the SnPS3 anode demonstrated excellent rate capability as well and delivered similar to 315 mAh g(-1) at a high specific current of 2 A g(-1) Furthermore, the lithium-storage mechanism was investigated through cyclic voltammetry and ex situ X-ray diffraction and Xray photoelectron spectroscopy studies. Studies of SnPS3 anode in a full cell configuration by coupling with commercial LiNi0.33Co0.33Mn0.33O2 cathode are also presented. The outstanding electrochemical performance demonstrated by the SnPS3 anode calls for further research into this novel class of metal thiophosphites for energy storage applications. |
Kenry, ; Lee, Wong Cheng; Loh, Kian Ping; Lim, Chwee Teck When stem cells meet graphene: Opportunities and challenges in regenerative medicine Journal Article BIOMATERIALS, 155 , pp. 236-250, 2018, ISSN: 0142-9612. @article{ISI:000419539000020, title = {When stem cells meet graphene: Opportunities and challenges in regenerative medicine}, author = {Kenry and Wong Cheng Lee and Kian Ping Loh and Chwee Teck Lim}, doi = {10.1016/j.biomaterials.2017.10.004}, times_cited = {7}, issn = {0142-9612}, year = {2018}, date = {2018-02-01}, journal = {BIOMATERIALS}, volume = {155}, pages = {236-250}, publisher = {ELSEVIER SCI LTD}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND}, abstract = {Recent advances in stem cell research and nanotechnology have significantly influenced the landscape of tissue engineering and regenerative medicine. Precise and reproducible control of the fate of stem cells and their lineage specification have, therefore, become more crucial than ever for the success of stem cell-based technologies. Extensive research has been geared towards developing materials that are capable of mimicking the physiological microenvironment of stem cells and at the same time, controlling their eventual fate. An interesting example of these materials is two-dimensional graphene and its related derivatives. A high specific surface area coupled with superior chemical stability, biocompatibility, and flexibility in functionalization render graphene-based nanomaterials one of the most exciting platforms for tissue engineering and regenerative medicine applications, especially for stem cell growth, proliferation, and differentiation. In this review, we discuss the love-hate relationship between stem cells and graphene-based nanomaterials in tissue engineering and regenerative medicine. We first discuss the role and importance of stem cells in tissue engineering and regenerative medicine. We then highlight the use of nanomaterials for stem cell control, the interaction between stem cells and graphene nano materials as well as their biocompatibility, biodistribution, and biodegradability considerations. We also offer our perspectives on the various challenges and opportunities facing the use of graphene and its derivatives for stem cell growth and differentiation. (C) 2017 The Authors. Published by Elsevier Ltd.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Recent advances in stem cell research and nanotechnology have significantly influenced the landscape of tissue engineering and regenerative medicine. Precise and reproducible control of the fate of stem cells and their lineage specification have, therefore, become more crucial than ever for the success of stem cell-based technologies. Extensive research has been geared towards developing materials that are capable of mimicking the physiological microenvironment of stem cells and at the same time, controlling their eventual fate. An interesting example of these materials is two-dimensional graphene and its related derivatives. A high specific surface area coupled with superior chemical stability, biocompatibility, and flexibility in functionalization render graphene-based nanomaterials one of the most exciting platforms for tissue engineering and regenerative medicine applications, especially for stem cell growth, proliferation, and differentiation. In this review, we discuss the love-hate relationship between stem cells and graphene-based nanomaterials in tissue engineering and regenerative medicine. We first discuss the role and importance of stem cells in tissue engineering and regenerative medicine. We then highlight the use of nanomaterials for stem cell control, the interaction between stem cells and graphene nano materials as well as their biocompatibility, biodistribution, and biodegradability considerations. We also offer our perspectives on the various challenges and opportunities facing the use of graphene and its derivatives for stem cell growth and differentiation. (C) 2017 The Authors. Published by Elsevier Ltd. |
Sreekanth, Kandammathe Valiyaveedu; Sreejith, Sivaramapanicker; Han, Song; Mishra, Amita; Chen, Xiaoxuan; Sun, Handong; Lim, Chwee Teck; Singh, Ranjan Biosensing with the singular phase of an ultrathin metal-dielectric nanophotonic cavity Journal Article NATURE COMMUNICATIONS, 9 , 2018, ISSN: 2041-1723. @article{ISI:000423424800004, title = {Biosensing with the singular phase of an ultrathin metal-dielectric nanophotonic cavity}, author = {Kandammathe Valiyaveedu Sreekanth and Sivaramapanicker Sreejith and Song Han and Amita Mishra and Xiaoxuan Chen and Handong Sun and Chwee Teck Lim and Ranjan Singh}, doi = {10.1038/s41467-018-02860-6}, times_cited = {5}, issn = {2041-1723}, year = {2018}, date = {2018-01-25}, journal = {NATURE COMMUNICATIONS}, volume = {9}, publisher = {NATURE PUBLISHING GROUP}, address = {MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND}, abstract = {The concept of point of darkness has received much attention for biosensing based on phase-sensitive detection and perfect absorption of light. The maximum phase change is possible at the point of darkness where the reflection is almost zero. To date, this has been experimentally realized using different material systems through the concept of topological darkness. However, complex nanopatterning techniques are required to realize topological darkness. Here, we report an approach to realize perfect absorption and extreme phase singularity using a simple metal-dielectric multilayer thin-film stack. The multilayer stack works on the principle of an asymmetric Fabry-Perot cavity and shows an abrupt phase change at the reflectionless point due to the presence of a highly absorbing ultrathin film of germanium in the stack. In the proof-of-concept phase-sensitive biosensing experiments, we functionalize the film surface with an ultrathin layer of biotin-thiol to capture streptavidin at a low concentration of 1 pM.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The concept of point of darkness has received much attention for biosensing based on phase-sensitive detection and perfect absorption of light. The maximum phase change is possible at the point of darkness where the reflection is almost zero. To date, this has been experimentally realized using different material systems through the concept of topological darkness. However, complex nanopatterning techniques are required to realize topological darkness. Here, we report an approach to realize perfect absorption and extreme phase singularity using a simple metal-dielectric multilayer thin-film stack. The multilayer stack works on the principle of an asymmetric Fabry-Perot cavity and shows an abrupt phase change at the reflectionless point due to the presence of a highly absorbing ultrathin film of germanium in the stack. In the proof-of-concept phase-sensitive biosensing experiments, we functionalize the film surface with an ultrathin layer of biotin-thiol to capture streptavidin at a low concentration of 1 pM. |
2017 |
Geldert, Alisha; Kenry, ; Lim, Chwee Teck Paper-based MoS2 nanosheet-mediated FRET aptasensor for rapid malaria diagnosis Journal Article SCIENTIFIC REPORTS, 7 , 2017, ISSN: 2045-2322. @article{ISI:000417796000030, title = {Paper-based MoS_{2} nanosheet-mediated FRET aptasensor for rapid malaria diagnosis}, author = {Alisha Geldert and Kenry and Chwee Teck Lim}, doi = {10.1038/s41598-017-17616-3}, times_cited = {0}, issn = {2045-2322}, year = {2017}, date = {2017-12-13}, journal = {SCIENTIFIC REPORTS}, volume = {7}, publisher = {NATURE PORTFOLIO}, address = {HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY}, abstract = {There has been growing interest in the development of paper-based biosensors because their simplicity and low cost are attractive for point-of-care diagnosis, especially in low-resource areas. However, only a limited range of paper materials-primarily chromatography papers-have been incorporated into diagnostics thus far. Here, we investigate the performance of different types of paper in order to develop an aptamer-and MoS2 nanosheet-based sensor relying on fluorescence resonance energy transfer (FRET) to signal the presence of a target protein. An aptamer which binds to a malarial biomarker, Plasmodium lactate dehydrogenase (pLDH), is chosen for this study, as point-of-care diagnostics would be especially advantageous in low-resource areas, such as those where malaria is prevalent. We observe that of all papers tested, a measurable and specific fluorescence recovery can only be produced on the sensor created with printer paper, while no significant fluorescence recovery is generated on sensors made from other types of paper, including chromatography, lens, and filter papers. Therefore, our findings demonstrate the importance of careful material selection for the development of a paper-based diagnostic test, and suggest that commercially-available products such as printer paper may serve as viable materials to develop cost-effective and simple diagnostics.}, keywords = {}, pubstate = {published}, tppubtype = {article} } There has been growing interest in the development of paper-based biosensors because their simplicity and low cost are attractive for point-of-care diagnosis, especially in low-resource areas. However, only a limited range of paper materials-primarily chromatography papers-have been incorporated into diagnostics thus far. Here, we investigate the performance of different types of paper in order to develop an aptamer-and MoS2 nanosheet-based sensor relying on fluorescence resonance energy transfer (FRET) to signal the presence of a target protein. An aptamer which binds to a malarial biomarker, Plasmodium lactate dehydrogenase (pLDH), is chosen for this study, as point-of-care diagnostics would be especially advantageous in low-resource areas, such as those where malaria is prevalent. We observe that of all papers tested, a measurable and specific fluorescence recovery can only be produced on the sensor created with printer paper, while no significant fluorescence recovery is generated on sensors made from other types of paper, including chromatography, lens, and filter papers. Therefore, our findings demonstrate the importance of careful material selection for the development of a paper-based diagnostic test, and suggest that commercially-available products such as printer paper may serve as viable materials to develop cost-effective and simple diagnostics. |
Xi, Wang; Sonam, Surabhi; Saw, Thuan Beng; Ladoux, Benoit; Lim, Chwee Teck Emergent patterns of collective cell migration under tubular confinement Journal Article NATURE COMMUNICATIONS, 8 , 2017, ISSN: 2041-1723. @article{ISI:000415262500005, title = {Emergent patterns of collective cell migration under tubular confinement}, author = {Wang Xi and Surabhi Sonam and Thuan Beng Saw and Benoit Ladoux and Chwee Teck Lim}, doi = {10.1038/s41467-017-01390-x}, times_cited = {1}, issn = {2041-1723}, year = {2017}, date = {2017-11-15}, journal = {NATURE COMMUNICATIONS}, volume = {8}, publisher = {NATURE PUBLISHING GROUP}, address = {MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND}, abstract = {Collective epithelial behaviors are essential for the development of lumens in organs. However, conventional assays of planar systems fail to replicate cell cohorts of tubular structures that advance in concerted ways on out-of-plane curved and confined surfaces, such as ductal elongation in vivo. Here, we mimic such coordinated tissue migration by forming lumens of epithelial cell sheets inside microtubes of 1-10 cell lengths in diameter. We show that these cell tubes reproduce the physiological apical-basal polarity, and have actin alignment, cell orientation, tissue organization, and migration modes that depend on the extent of tubular confinement and/or curvature. In contrast to flat constraint, the cell sheets in a highly constricted smaller microtube demonstrate slow motion with periodic relaxation, but fast overall movement in large microtubes. Altogether, our findings provide insights into the emerging migratory modes for epithelial migration and growth under tubular confinement, which are reminiscent of the in vivo scenario.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Collective epithelial behaviors are essential for the development of lumens in organs. However, conventional assays of planar systems fail to replicate cell cohorts of tubular structures that advance in concerted ways on out-of-plane curved and confined surfaces, such as ductal elongation in vivo. Here, we mimic such coordinated tissue migration by forming lumens of epithelial cell sheets inside microtubes of 1-10 cell lengths in diameter. We show that these cell tubes reproduce the physiological apical-basal polarity, and have actin alignment, cell orientation, tissue organization, and migration modes that depend on the extent of tubular confinement and/or curvature. In contrast to flat constraint, the cell sheets in a highly constricted smaller microtube demonstrate slow motion with periodic relaxation, but fast overall movement in large microtubes. Altogether, our findings provide insights into the emerging migratory modes for epithelial migration and growth under tubular confinement, which are reminiscent of the in vivo scenario. |
Kenry, ; Lim, Ying Bena; Nai, Mui Hoon; Cao, Jianshu; Loh, Kian Ping; Lim, Chwee Teck Graphene oxide inhibits malaria parasite invasion and delays parasitic growth in vitro Journal Article NANOSCALE, 9 (37), pp. 14065-14073, 2017, ISSN: 2040-3364. @article{ISI:000411862400024, title = {Graphene oxide inhibits malaria parasite invasion and delays parasitic growth \textit{in vitro}}, author = {Kenry and Ying Bena Lim and Mui Hoon Nai and Jianshu Cao and Kian Ping Loh and Chwee Teck Lim}, doi = {10.1039/c7nr06007f}, times_cited = {0}, issn = {2040-3364}, year = {2017}, date = {2017-10-07}, journal = {NANOSCALE}, volume = {9}, number = {37}, pages = {14065-14073}, publisher = {ROYAL SOC CHEMISTRY}, address = {THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND}, abstract = {The interactions between graphene oxide (GO) and various biological entities have been actively investigated in recent years, resulting in numerous potential bioapplications of these nanomaterials. Despite this, the biological interactions between GO and disease-causing protozoan parasites have not been well elucidated and remain relatively unexplored. Here, we investigate the in vitro interactions between GO nanosheets and a particular species of malaria parasites, Plasmodium falciparum (P. falciparum). We hypothesize that GO nanosheets may exhibit antimalarial characteristic via action mechanisms of physical obstruction of P. falciparum parasites as well as nutrient depletion. To ascertain this, we characterize the physical interactions between GO nanosheets, red blood cells (RBCs), and malarial parasites as well as the adsorption of several biomolecules necessary for parasitic survival and growth on GO nanosheets. Subsequent to establishing the origin of this antimalarial behavior of GO nanosheets, their efficiency in inhibiting parasite invasion is evaluated. We observe that GO nanosheets at various tested concentrations significantly inhibit the invasion of malaria parasites into RBCs. Furthermore, GO nanosheets delay parasite progression from the ring to the trophozoite stage. Overall, this study may further shed light on the graphene-parasite interactions and potentially facilitate the development of nanomaterial-based strategies for combating malaria.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The interactions between graphene oxide (GO) and various biological entities have been actively investigated in recent years, resulting in numerous potential bioapplications of these nanomaterials. Despite this, the biological interactions between GO and disease-causing protozoan parasites have not been well elucidated and remain relatively unexplored. Here, we investigate the in vitro interactions between GO nanosheets and a particular species of malaria parasites, Plasmodium falciparum (P. falciparum). We hypothesize that GO nanosheets may exhibit antimalarial characteristic via action mechanisms of physical obstruction of P. falciparum parasites as well as nutrient depletion. To ascertain this, we characterize the physical interactions between GO nanosheets, red blood cells (RBCs), and malarial parasites as well as the adsorption of several biomolecules necessary for parasitic survival and growth on GO nanosheets. Subsequent to establishing the origin of this antimalarial behavior of GO nanosheets, their efficiency in inhibiting parasite invasion is evaluated. We observe that GO nanosheets at various tested concentrations significantly inhibit the invasion of malaria parasites into RBCs. Furthermore, GO nanosheets delay parasite progression from the ring to the trophozoite stage. Overall, this study may further shed light on the graphene-parasite interactions and potentially facilitate the development of nanomaterial-based strategies for combating malaria. |
Xi, Wang; Kong, Fang; Yeo, Joo Chuan; Yu, Longteng; Sonam, Surabhi; Dao, Ming; Gong, Xiaobo; Lim, Chwee Teck Soft tubular microfluidics for 2D and 3D applications Journal Article PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, 114 (40), pp. 10590-10595, 2017, ISSN: 0027-8424. @article{ISI:000412130500048, title = {Soft tubular microfluidics for 2D and 3D applications}, author = {Wang Xi and Fang Kong and Joo Chuan Yeo and Longteng Yu and Surabhi Sonam and Ming Dao and Xiaobo Gong and Chwee Teck Lim}, doi = {10.1073/pnas.1712195114}, times_cited = {3}, issn = {0027-8424}, year = {2017}, date = {2017-10-03}, journal = {PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA}, volume = {114}, number = {40}, pages = {10590-10595}, publisher = {NATL ACAD SCIENCES}, address = {2101 CONSTITUTION AVE NW, WASHINGTON, DC 20418 USA}, abstract = {Microfluidics has been the key component for many applications, including biomedical devices, chemical processors, microactuators, and even wearable devices. This technology relies on soft lithography fabrication which requires cleanroom facilities. Although popular, this method is expensive and labor-intensive. Furthermore, current conventional microfluidic chips precludes reconfiguration, making reiterations in design very time-consuming and costly. To address these intrinsic drawbacks of microfabrication, we present an alternative solution for the rapid prototyping of microfluidic elements such as microtubes, valves, and pumps. In addition, we demonstrate how microtubes with channels of various lengths and cross-sections can be attached modularly into 2D and 3D microfluidic systems for functional applications. We introduce a facile method of fabricating elastomeric microtubes as the basic building blocks for microfluidic devices. These microtubes are transparent, biocompatible, highly deformable, and customizable to various sizes and cross-sectional geometries. By configuring the microtubes into deterministic geometry, we enable rapid, low-cost formation of microfluidic assemblies without compromising their precision and functionality. We demonstrate configurable 2D and 3D microfluidic systems for applications in different domains. These include microparticle sorting, microdroplet generation, biocatalytic micromotor, triboelectric sensor, and even wearable sensing. Our approach, termed soft tubular microfluidics, provides a simple, cheaper, and faster solution for users lacking proficiency and access to cleanroom facilities to design and rapidly construct microfluidic devices for their various applications and needs.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Microfluidics has been the key component for many applications, including biomedical devices, chemical processors, microactuators, and even wearable devices. This technology relies on soft lithography fabrication which requires cleanroom facilities. Although popular, this method is expensive and labor-intensive. Furthermore, current conventional microfluidic chips precludes reconfiguration, making reiterations in design very time-consuming and costly. To address these intrinsic drawbacks of microfabrication, we present an alternative solution for the rapid prototyping of microfluidic elements such as microtubes, valves, and pumps. In addition, we demonstrate how microtubes with channels of various lengths and cross-sections can be attached modularly into 2D and 3D microfluidic systems for functional applications. We introduce a facile method of fabricating elastomeric microtubes as the basic building blocks for microfluidic devices. These microtubes are transparent, biocompatible, highly deformable, and customizable to various sizes and cross-sectional geometries. By configuring the microtubes into deterministic geometry, we enable rapid, low-cost formation of microfluidic assemblies without compromising their precision and functionality. We demonstrate configurable 2D and 3D microfluidic systems for applications in different domains. These include microparticle sorting, microdroplet generation, biocatalytic micromotor, triboelectric sensor, and even wearable sensing. Our approach, termed soft tubular microfluidics, provides a simple, cheaper, and faster solution for users lacking proficiency and access to cleanroom facilities to design and rapidly construct microfluidic devices for their various applications and needs. |
Kenry, ; Geldert, Alisha; Liu, Yanpeng; Loh, Kian Ping; Lim, Chwee Teck Nano-bio interactions between carbon nanomaterials and blood plasma proteins: why oxygen functionality matters Journal Article NPG ASIA MATERIALS, 9 , 2017, ISSN: 1884-4049. @article{ISI:000407959700004, title = {Nano-bio interactions between carbon nanomaterials and blood plasma proteins: why oxygen functionality matters}, author = {Kenry and Alisha Geldert and Yanpeng Liu and Kian Ping Loh and Chwee Teck Lim}, doi = {10.1038/am.2017.129}, times_cited = {0}, issn = {1884-4049}, year = {2017}, date = {2017-08-18}, journal = {NPG ASIA MATERIALS}, volume = {9}, publisher = {NATURE PUBLISHING GROUP}, address = {75 VARICK ST, 9TH FLR, NEW YORK, NY 10013-1917 USA}, abstract = {Carbon nanomaterials are some of the most versatile nanomaterials. Along with increasing explorations into their utilization in a plethora of biological and biomedical applications, there have been emerging interests and needs in understanding the molecular hemocompatibility of these engineered nanomaterials when coming into contact with blood. Here, we evaluate the nano-bio interactions of one-dimensional (1D) and two-dimensional (2D) carbon nanomaterials with blood plasma proteins. Different facets of the nanomaterial-protein interactions, specifically, the adsorption, equilibrium binding and conformational stability of proteins upon association with carbon nanomaterials are established, based on the quantification of various parameters, such as association constant, binding cooperativity and protein secondary structural change. In light of our data, we demonstrate that the carbon nanomaterial-plasma protein interactions may be significantly influenced by the density of the oxygenated functionalities of the nanomaterials and to a certain extent, their dimensionality and surface area. This work offers a broad insight into the nano-bio interactions between carbon nanomaterials and blood plasma proteins and provides a strong basis for the design and use of 1D and 2D carbon nanomaterials for a wide variety of bioapplications.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Carbon nanomaterials are some of the most versatile nanomaterials. Along with increasing explorations into their utilization in a plethora of biological and biomedical applications, there have been emerging interests and needs in understanding the molecular hemocompatibility of these engineered nanomaterials when coming into contact with blood. Here, we evaluate the nano-bio interactions of one-dimensional (1D) and two-dimensional (2D) carbon nanomaterials with blood plasma proteins. Different facets of the nanomaterial-protein interactions, specifically, the adsorption, equilibrium binding and conformational stability of proteins upon association with carbon nanomaterials are established, based on the quantification of various parameters, such as association constant, binding cooperativity and protein secondary structural change. In light of our data, we demonstrate that the carbon nanomaterial-plasma protein interactions may be significantly influenced by the density of the oxygenated functionalities of the nanomaterials and to a certain extent, their dimensionality and surface area. This work offers a broad insight into the nano-bio interactions between carbon nanomaterials and blood plasma proteins and provides a strong basis for the design and use of 1D and 2D carbon nanomaterials for a wide variety of bioapplications. |
Geldert, Alisha; Kenry, ; Zhang, Xiao; Zhang, Hua; Lim, Chwee Teck Enhancing the sensing specificity of a MoS2 nanosheet-based FRET aptasensor using a surface blocking strategy Journal Article 23 ANALYST, 142 (14), pp. 2570-2577, 2017, ISSN: 0003-2654. @article{ISI:000405373600005, title = {Enhancing the sensing specificity of a MoS_{2} nanosheet-based FRET aptasensor using a surface blocking strategy}, author = {Alisha Geldert and Kenry and Xiao Zhang and Hua Zhang and Chwee Teck Lim}, doi = {10.1039/c7an00640c}, times_cited = {23}, issn = {0003-2654}, year = {2017}, date = {2017-07-21}, journal = {ANALYST}, volume = {142}, number = {14}, pages = {2570-2577}, publisher = {ROYAL SOC CHEMISTRY}, address = {THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND}, abstract = {Aptamer-based biosensing, which uses short, single-stranded nucleic acid segments to bind to a target, can be advantageous over antibody-based diagnostics due to the ease of synthesis and high stability of aptamers. However, the development of most aptamer-based sensors (aptasensors) is still in its initial stages and many factors affecting their performance have not been studied in great detail. Here, we enhance the sensing specificity of a fluorescence resonance energy transfer (FRET)-based MoS2 nanosheet aptasensor in detecting the malarial biomarker Plasmodium lactate dehydrogenase (pLDH). In this sensing scheme, the presence of target is signaled by an increase in fluorescence when fluores-cently-labeled aptamers bind to pLDH and release from a quenching material. Interestingly, unlike most of the reported literature on aptasensors, we observe that non-target proteins also cause a considerable increase in the detected fluorescence. This may be due to the nonspecific adsorption of proteins onto the fluorescence quencher, leading to the displacement of aptamers from the quencher surface. To reduce this nonspecific association and to enhance the sensor specificity, we propose the application of a surface blocking agent to the quenching material. Importantly, we demonstrate that the sensing specificity of the MoS2 nanosheet-based aptasensor towards target pLDH biomolecules can be significantly enhanced through surface passivation, thus contributing to the development of highly selective and robust point-of-care malaria diagnostics.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Aptamer-based biosensing, which uses short, single-stranded nucleic acid segments to bind to a target, can be advantageous over antibody-based diagnostics due to the ease of synthesis and high stability of aptamers. However, the development of most aptamer-based sensors (aptasensors) is still in its initial stages and many factors affecting their performance have not been studied in great detail. Here, we enhance the sensing specificity of a fluorescence resonance energy transfer (FRET)-based MoS2 nanosheet aptasensor in detecting the malarial biomarker Plasmodium lactate dehydrogenase (pLDH). In this sensing scheme, the presence of target is signaled by an increase in fluorescence when fluores-cently-labeled aptamers bind to pLDH and release from a quenching material. Interestingly, unlike most of the reported literature on aptasensors, we observe that non-target proteins also cause a considerable increase in the detected fluorescence. This may be due to the nonspecific adsorption of proteins onto the fluorescence quencher, leading to the displacement of aptamers from the quencher surface. To reduce this nonspecific association and to enhance the sensor specificity, we propose the application of a surface blocking agent to the quenching material. Importantly, we demonstrate that the sensing specificity of the MoS2 nanosheet-based aptasensor towards target pLDH biomolecules can be significantly enhanced through surface passivation, thus contributing to the development of highly selective and robust point-of-care malaria diagnostics. |