Since its creation,single-molecule optical imaging has revolutionized the study of catalytic processes,yet its application largely relies on probing fluorogenic reactions.To overcome this limitation,we propose the Flu...Since its creation,single-molecule optical imaging has revolutionized the study of catalytic processes,yet its application largely relies on probing fluorogenic reactions.To overcome this limitation,we propose the Fluorogenic Linkage Integration for Nonfluorescent Transformation(FLINT)approach,an imaging method to resolve nonfluorogenic reactions at the single-molecule level.Using glucose oxidation as a model reaction,we coupled this nonfluorogenic reaction with a fluorogenic Amplex Red(AR)→resorufin(RF)transformation to create a cascading reaction.This integration allowed us to monitor single-turnover events and extract key kinetic parameters for glucose oxidation despite their being invisible under the optical microscope.Our ensemble measurements combining cyclic voltammetry and fluorescence spectroscopy confirmed the cascade reaction mechanism and revealed first-order kinetics for both elementary reaction steps.At the single-molecule level,turnover time analysis provided detailed information on the reaction kinetics,distinguishing the relatively fast glucose oxidation from slower AR oxidation.We further confirmed the validity of the FLINT approach by comparing the catalytic performances of 5 nm gold nanoparticles(AuNPs)against that of 18×52 nm gold nanorods(AuNRs)and AuNP@DNA coronazymes.Furthermore,FLINT was used to evaluate the chiral selectivity of D-and L-glucose on coronazymes,suggesting the potential application of FLINT in enantioselective reactions.The FLINT approach is a significant advancement in single-molecule imaging as it enables the study of nonfluorogenic reactions with high spatiotemporal resolution.展开更多
Gold nanoparticles are frequently employed as nanozyme materials due to their capacity to catalyze various enzymatic reactions.Given their plasmonic nature,gold nanoparticles have also found extensive utility in chemi...Gold nanoparticles are frequently employed as nanozyme materials due to their capacity to catalyze various enzymatic reactions.Given their plasmonic nature,gold nanoparticles have also found extensive utility in chemical and photochemical catalysis owing to their ability to generate excitons upon exposure to light.However,their potential for plasmon-assisted catalytic enhancement as nanozymes has remained largely unexplored due to the inherent challenge of rapid charge recombination.In this study,we have developed a strategy involving the encapsulation of gold nanorods(AuNRs)within a titanium dioxide(TiO_(2))shell to facilitate the efficient separation of hot electron/hole pairs,thereby enhancing nanozyme reactivity.Our investigations have revealed a remarkable 10-fold enhancement in reactivity when subjected to 530 nm light excitation following the introduction of a TiO_(2) shell.Leveraging single-molecule kinetic analyses,we discovered that the presence of the TiO_(2) shell not only amplifies catalytic reactivity by prolonging charge relaxation times but also engenders additional reactive sites within the nanozyme's intricate structure.We anticipate that further enhancements in nanozyme performance can be achieved by optimizing interfacial interactions between plasmonic metals and semiconductors.展开更多
基金the National Science Foundation(NSF)(No.CHE2247709)for grant supportH.M.acknowledges the National Institute of Health(NIH)(No.R01 CA252827).
文摘Since its creation,single-molecule optical imaging has revolutionized the study of catalytic processes,yet its application largely relies on probing fluorogenic reactions.To overcome this limitation,we propose the Fluorogenic Linkage Integration for Nonfluorescent Transformation(FLINT)approach,an imaging method to resolve nonfluorogenic reactions at the single-molecule level.Using glucose oxidation as a model reaction,we coupled this nonfluorogenic reaction with a fluorogenic Amplex Red(AR)→resorufin(RF)transformation to create a cascading reaction.This integration allowed us to monitor single-turnover events and extract key kinetic parameters for glucose oxidation despite their being invisible under the optical microscope.Our ensemble measurements combining cyclic voltammetry and fluorescence spectroscopy confirmed the cascade reaction mechanism and revealed first-order kinetics for both elementary reaction steps.At the single-molecule level,turnover time analysis provided detailed information on the reaction kinetics,distinguishing the relatively fast glucose oxidation from slower AR oxidation.We further confirmed the validity of the FLINT approach by comparing the catalytic performances of 5 nm gold nanoparticles(AuNPs)against that of 18×52 nm gold nanorods(AuNRs)and AuNP@DNA coronazymes.Furthermore,FLINT was used to evaluate the chiral selectivity of D-and L-glucose on coronazymes,suggesting the potential application of FLINT in enantioselective reactions.The FLINT approach is a significant advancement in single-molecule imaging as it enables the study of nonfluorogenic reactions with high spatiotemporal resolution.
基金the National Science Foundation(NSF)(No.CHE2247709)for grant support.
文摘Gold nanoparticles are frequently employed as nanozyme materials due to their capacity to catalyze various enzymatic reactions.Given their plasmonic nature,gold nanoparticles have also found extensive utility in chemical and photochemical catalysis owing to their ability to generate excitons upon exposure to light.However,their potential for plasmon-assisted catalytic enhancement as nanozymes has remained largely unexplored due to the inherent challenge of rapid charge recombination.In this study,we have developed a strategy involving the encapsulation of gold nanorods(AuNRs)within a titanium dioxide(TiO_(2))shell to facilitate the efficient separation of hot electron/hole pairs,thereby enhancing nanozyme reactivity.Our investigations have revealed a remarkable 10-fold enhancement in reactivity when subjected to 530 nm light excitation following the introduction of a TiO_(2) shell.Leveraging single-molecule kinetic analyses,we discovered that the presence of the TiO_(2) shell not only amplifies catalytic reactivity by prolonging charge relaxation times but also engenders additional reactive sites within the nanozyme's intricate structure.We anticipate that further enhancements in nanozyme performance can be achieved by optimizing interfacial interactions between plasmonic metals and semiconductors.
