I was fortunate to,work with/for Dr Britton Chance as his postdoctoral fellow,in the Bio-chemistry and Biophysics Department at the University of Pennsy lvania,bet ween August 1991and January 1994.As anyone who worked...I was fortunate to,work with/for Dr Britton Chance as his postdoctoral fellow,in the Bio-chemistry and Biophysics Department at the University of Pennsy lvania,bet ween August 1991and January 1994.As anyone who worked for him,I had a suficient dosage of"Brtton Chance"over the years.Initilly,to me,I felt that he was someone who was above regular people and faraway to reach,Then I became to know him as a person,who was simple and complicated at thesame time,with a persistent pursuit for his life interests,i.e,the advancement in science relatedto human health.As far as it goes to science(and perhaps with sailing),he had few boundary:Hecommunicated with any age group,any one from any country with any cultural background.Anyscientists were welcomed to his lab,his own house,and even his boat.He was happy with minimalmaterial things.He kept his friendship faithfully.From him,I came to lmow how much oneperson can actually do during a life time.am very gratefil that I got to lnow him during my lifepath In this paper,list some of my experiences with hin scientifically and also how and what ilearned from him impacted my research and personal life.展开更多
We show by molecular dynamics simulations that configuration-sensitive molecular spectroscopy can be realized on optimally doped graphene sheets vibrated by an oscillatory electric field.High selectivity of the spectr...We show by molecular dynamics simulations that configuration-sensitive molecular spectroscopy can be realized on optimally doped graphene sheets vibrated by an oscillatory electric field.High selectivity of the spectroscopy is achieved by maximizing Coulombic binding between the detected molecule and a specific nest,formed for this molecule on the graphene sheet by substituting selected carbon atoms with boron and nitrogen dopants.One can detect binding of different isomers to the nest from the frequency shifts of selected vibrational modes of the combined system.As an illustrative example,we simulate detection of hexanitrostilbene enantiomers in chiral nests formed on graphene.展开更多
Atomic layers are sought after for molecular sensing due to their available high surface interaction area,and different types of monolayers are attempted for sensing in the recent past.However,their chemical stability...Atomic layers are sought after for molecular sensing due to their available high surface interaction area,and different types of monolayers are attempted for sensing in the recent past.However,their chemical stability towards these molecules is questioned in recent times and alternate methods need to be developed to circumvent such issues,while maintaining high sensitivity.Here,the van der Waals(vdWs)stacks of molybdenum disulfide(MoS_(2))and graphene are shown for their stable electrochemical sensing towards ascorbic acid(AA)and dopamine(DA)-two important biomolecules.AA is known to chemically react with MoS_(2) leading to unstable sensing platform,while here the graphene coverage is shown to protect the MoS_(2) even from low-energy plasma exposure while keeping the same high sensitivity.Upon proving the graphene-based protection of the sensor,such a sensing platform is shown for its applicability in DA sensing,where it is found to give a linear response in a wide range of concentrations(2.5 to 600μmol·L^(−1))and even selective sensing in the presence of AA.Such a stack is found to be not merely giving protection to the beneath MoS_(2) layer but also the inter-layer charge transfer due to work function differences being beneficial in bringing fast and high sensitivity to the next-generation sensors and point-of-care devices.展开更多
Optical barcodes have demonstrated a great potential in multiplexed bioassays and cell tracking for their distinctive spectral fingerprints.The vast majority of optical barcodes were designed to identify a specific ta...Optical barcodes have demonstrated a great potential in multiplexed bioassays and cell tracking for their distinctive spectral fingerprints.The vast majority of optical barcodes were designed to identify a specific target by fluorescence emission spectra,without being able to characterize dynamic changes in response to analytes through time.To overcome these limitations,the concept of the bioresponsive dynamic photonic barcode was proposed by exploiting interfacial energy transfer between a microdroplet cavity and binding molecules.Whispering-gallery modes resulting from cavity-enhanced energy transfer were therefore converted into photonic barcodes to identify binding activities,in which more than trillions of distinctive barcodes could be generated by a single droplet.Dynamic spectral barcoding was achieved by a significant improvement in terms of signal-to-noise ratio upon binding to target molecules.Theoretical studies and experiments were conducted to elucidate the effect of different cavity sizes and analyte concentrations.Timeresolved fluorescence lifetime was implemented to investigate the role of radiative and non-radiative energy transfer.Finally,microdroplet photonic barcodes were employed in biodetection to exhibit great potential in fulfilling biomedical applications.展开更多
文摘I was fortunate to,work with/for Dr Britton Chance as his postdoctoral fellow,in the Bio-chemistry and Biophysics Department at the University of Pennsy lvania,bet ween August 1991and January 1994.As anyone who worked for him,I had a suficient dosage of"Brtton Chance"over the years.Initilly,to me,I felt that he was someone who was above regular people and faraway to reach,Then I became to know him as a person,who was simple and complicated at thesame time,with a persistent pursuit for his life interests,i.e,the advancement in science relatedto human health.As far as it goes to science(and perhaps with sailing),he had few boundary:Hecommunicated with any age group,any one from any country with any cultural background.Anyscientists were welcomed to his lab,his own house,and even his boat.He was happy with minimalmaterial things.He kept his friendship faithfully.From him,I came to lmow how much oneperson can actually do during a life time.am very gratefil that I got to lnow him during my lifepath In this paper,list some of my experiences with hin scientifically and also how and what ilearned from him impacted my research and personal life.
基金JR would like to acknowledge the generous support from the National Defense Science and Engineering Fellowship sponsored by the Department of Defense.
文摘We show by molecular dynamics simulations that configuration-sensitive molecular spectroscopy can be realized on optimally doped graphene sheets vibrated by an oscillatory electric field.High selectivity of the spectroscopy is achieved by maximizing Coulombic binding between the detected molecule and a specific nest,formed for this molecule on the graphene sheet by substituting selected carbon atoms with boron and nitrogen dopants.One can detect binding of different isomers to the nest from the frequency shifts of selected vibrational modes of the combined system.As an illustrative example,we simulate detection of hexanitrostilbene enantiomers in chiral nests formed on graphene.
基金This work was financially supported by Department of Science and Technology,India extramural research grant(Grant No.EMR/2017/000513)intramural grants at TIFR Hyderabad from the Department of Atomic Energy(DAE).
文摘Atomic layers are sought after for molecular sensing due to their available high surface interaction area,and different types of monolayers are attempted for sensing in the recent past.However,their chemical stability towards these molecules is questioned in recent times and alternate methods need to be developed to circumvent such issues,while maintaining high sensitivity.Here,the van der Waals(vdWs)stacks of molybdenum disulfide(MoS_(2))and graphene are shown for their stable electrochemical sensing towards ascorbic acid(AA)and dopamine(DA)-two important biomolecules.AA is known to chemically react with MoS_(2) leading to unstable sensing platform,while here the graphene coverage is shown to protect the MoS_(2) even from low-energy plasma exposure while keeping the same high sensitivity.Upon proving the graphene-based protection of the sensor,such a sensing platform is shown for its applicability in DA sensing,where it is found to give a linear response in a wide range of concentrations(2.5 to 600μmol·L^(−1))and even selective sensing in the presence of AA.Such a stack is found to be not merely giving protection to the beneath MoS_(2) layer but also the inter-layer charge transfer due to work function differences being beneficial in bringing fast and high sensitivity to the next-generation sensors and point-of-care devices.
基金We would like to thank the Centre of Bio-Devices and Bioinformatics and CNRS International—Nanyang Technological University-Thales Research Alliance(CINTRA)for lab supportWe would also like to thank NTU for the startup grant(SUG-M4082308.040).
文摘Optical barcodes have demonstrated a great potential in multiplexed bioassays and cell tracking for their distinctive spectral fingerprints.The vast majority of optical barcodes were designed to identify a specific target by fluorescence emission spectra,without being able to characterize dynamic changes in response to analytes through time.To overcome these limitations,the concept of the bioresponsive dynamic photonic barcode was proposed by exploiting interfacial energy transfer between a microdroplet cavity and binding molecules.Whispering-gallery modes resulting from cavity-enhanced energy transfer were therefore converted into photonic barcodes to identify binding activities,in which more than trillions of distinctive barcodes could be generated by a single droplet.Dynamic spectral barcoding was achieved by a significant improvement in terms of signal-to-noise ratio upon binding to target molecules.Theoretical studies and experiments were conducted to elucidate the effect of different cavity sizes and analyte concentrations.Timeresolved fluorescence lifetime was implemented to investigate the role of radiative and non-radiative energy transfer.Finally,microdroplet photonic barcodes were employed in biodetection to exhibit great potential in fulfilling biomedical applications.
