Intrinsically disordered proteins(IDPs)and their regions(IDRs)play crucial roles in cellular func-tions despite their lack of stable three-dimensional structures.In this study,we investigate the interac-tions between ...Intrinsically disordered proteins(IDPs)and their regions(IDRs)play crucial roles in cellular func-tions despite their lack of stable three-dimensional structures.In this study,we investigate the interac-tions between the C-terminal do-main of protein 4.1G(4.1G CTD)and the nuclear mitotic apparatus protein(NuMA)under varying pH and salt ion conditions to under-stand the regulatory mechanisms affecting their binding.4.1G CTD and NuMA bind effec-tively under neutral and alkaline conditions,but their interaction is disrupted under acidic conditions(pH 3.6).The protonation of positively charged residues at the C-terminal of 4.1G CTD under acidic conditions leads to increased electrostatic repulsion,weakening the overall binding free energy.Secondary structure analysis shows that specific regions of 4.1G CTD re-main stable under both pH conditions,but the C-terminal region(aa 990−1000)and the N-terminal region of NuMA(aa 1800−1810)exhibit significant reductions in secondary struc-ture probability under acidic conditions.Contact map analysis and solvent-accessible surface area analysis further support these findings by showing a reduced contact probability be-tween these regions under pH 3.6.These results provide a comprehensive understanding of how pH and ionic strength regulate the binding dynamics of 4.1G CTD and NuMA,emphasiz-ing the regulatory role of electrostatic interactions.展开更多
Photosynthetic organisms have developed various light-harvesting antenna systems to capture light and transfer energy to reaction centers(RCs).Simultaneous utilization of the integral membrane light-harvesting antenna...Photosynthetic organisms have developed various light-harvesting antenna systems to capture light and transfer energy to reaction centers(RCs).Simultaneous utilization of the integral membrane light-harvesting antenna(LH complex)and the extrinsic antenna(chlorosomes)makes the phototrophic bacterium Chloroflexus(Cfx.)aurantiacus an ideal model for studying filamentous anoxygenic phototrophs(FAPs).Here,we determined the structure of a minimal RC-LH photocomplex from Cfx.aurantiacus J-10-fl(CaRC-LH)at 3.05-Åresolution.The CaRC-LH binds only to seven LH subunits,which form a crescent-shaped antenna surrounding the movable menaquinone-10(QB)binding site of CaRC.In this complex with minimal LH units,an extra antenna is required to ensure sufficient light-gathering,providing a clear explanation for the presence of chlorosomes in Cfx.aurantiacus.More importantly,the semicircle of the antenna represents a novel RC-LH assembly pattern.Our structure provides a basis for understanding the existence of chlorosomes in Cfx.aurantiacus and the possible assembly pattern of RC-LH.展开更多
A new scheme of super-resolution optical fluctuation imaging(SOFI)is proposed to broaden its application in the high-order cumulant reconstruction by optimizing blinking characteristics,eliminating noise in raw data a...A new scheme of super-resolution optical fluctuation imaging(SOFI)is proposed to broaden its application in the high-order cumulant reconstruction by optimizing blinking characteristics,eliminating noise in raw data and applying multi-resolution analysis in cumulant reconstruction.A motor-driven rotating mask optical modulation system is designed to adjust the excitation lightfield and allows for fast deployment.Active-modulated fluorescence fluctuation superresolution microscopy with multi-resolution analysis(AMF-MRA-SOFI)demonstrates enhanced resolution ability and reconstruction quality in experiments performed on sample of conventional dyes,achieving a resolution of 100 nm in the fourth order compared to conventional SOFI reconstruction.Furthermore,our approach combining expansion super-resolution achieved a resolution at-57 nm.展开更多
The lignification triggered by biotic or abiotic stresses hardens fruits and vegetables and eventually influences their consumer appeal.Extensive prior efforts have been made to unveil the underlying mechanism of fles...The lignification triggered by biotic or abiotic stresses hardens fruits and vegetables and eventually influences their consumer appeal.Extensive prior efforts have been made to unveil the underlying mechanism of flesh lignification,primarily focused on its physicochemical and molecular biological properties.Nevertheless,most of these studies used destroyed and homogenized bulk tissues as analytes;as a result,potentially valuable spatial information was lost.In this study,the deposition of lignin in loquat flesh during lignification was visualized from the tissue level to the singlecell level by combining the advantages of stimulated Raman scattering(SRS)and spontaneous Raman microscopy using label-free in situ molecular imaging.SRS has the advantages of being fast and providing large-area chemical imaging to reveal the spatial heterogeneity of lignin and cell wall polysaccharide distribution in loquat flesh.After 2 days of storage at 0℃,increased lignins were observed by large-area SRS imaging.In addition,microscopic SRS images of the flesh cells indicated that the increased lignins were trapped in the cell corner(CC)and middle lamella(ML).Furthermore,the compositional and structural features of lignified cells(LCs),CC and ML of loquat flesh were investigated by spontaneous Raman microscopy,and the results showed that the LCs were a combination of lignin,cellulose,and hemicellulose,whereas CC and ML showed only deposited lignin and pectin without cross-linked cellulose and hemicellulose.This result further suggests that the lignins in the CC and ML regions of loquats were later synthesized alone during postharvest storage.This innovative combination of SRS and spontaneous Raman microscopy allows the label-free macroscale and fine chemical imaging of plant cell walls and will enhance our fundamental understanding of the structures and functions of the plant cell wall.展开更多
Prion diseases are associated with the misfolding of the normal helical cellular form of prion protein (PrPC) into the β-sheet-rich scrapie form (PrPSc) and the subsequent aggregation of PrPSc into amyloid fibrils. R...Prion diseases are associated with the misfolding of the normal helical cellular form of prion protein (PrPC) into the β-sheet-rich scrapie form (PrPSc) and the subsequent aggregation of PrPSc into amyloid fibrils. Recent studies demonstrated that a naturally occurring variant V127 of human PrPC is intrinsically resistant to prion conversion and aggregation, and can completely prevent prion diseases. However, the underlying molecular mechanism remains elusive. Herein we perform multiple microsecond molecular dynamics simulations on both wildtype (WT) and V127 variant of human PrPC to understand at atomic level the protective effect of V127 variant. Our simulations show that G127V mutation not only increases the rigidity of the S2–H2 loop between strand-2 (S2) and helix-2 (H2), but also allosterically enhances the stability of the H2 C-terminal region. Interestingly, previous studies reported that animals with rigid S2–H2 loop usually do not develop prion diseases, and the increase in H2 C-terminal stability can prevent misfolding and oligomerization of prion protein. The allosteric paths from G/V127 to H2 C-terminal region are identified using dynamical network analyses. Moreover, community network analyses illustrate that G127V mutation enhances the global correlations and intra-molecular interactions of PrP, thus stabilizing the overall PrPC structure and inhibiting its conversion into PrPSc. This study provides mechanistic understanding of human V127 variant in preventing prion conversion which may be helpful for the rational design of potent anti-prion compounds.展开更多
Microfuidic systems have been widely utilized in high-throughput biology analysis,but thedificulties in iquid manipulation and cell cultivation limit its application.This work has developed a new digital microfluidic(...Microfuidic systems have been widely utilized in high-throughput biology analysis,but thedificulties in iquid manipulation and cell cultivation limit its application.This work has developed a new digital microfluidic(DMF)system for on-demand droplet control.By adopting anextending-depth-of-field(EDoF)phase modulator to the optical system,the entire depth of themicrofluidic channel can be covered in one image without any refocusing process,ensuring that 95%of the particles in the droplet are captured within three shots together with shaking pro-cesses.With this system,suspension droplets are generated and droplets containing only oneyeast cll can be recognized,then each single cell is cultured in the array of the chip.Byobservingtheir growth in cell numbers and the green fluorescence protein(GFP)production via fluorescence imaging,the single cell with the highest production can be identified.The results haveproved the heterogeneity of yeast cells,and showed that the combined system can be applied forrapid single-cell sorting,cultivation,and analysis.展开更多
Understanding how the diversity of glycolipids,including how their chemical structures and composition affect their biological functions,is a remarkable fundamental challenge.In this work,we employed a rare monosaccha...Understanding how the diversity of glycolipids,including how their chemical structures and composition affect their biological functions,is a remarkable fundamental challenge.In this work,we employed a rare monosaccharide,3-deoxy-Dmanno-2-octulosonic acid(Kdo)to build a simple and biomimetic model to understand the diversity of glycolipids from the viewpoint of supramolecular chemistry.Kdo was chosen not only because its unusual 8-carbon acidic carbohydrate backbone is very different from common hexoses,but also because of its key structural role in lipopolysaccharides and prevalence in bacteria,plant life,and algae.It was found that although both of the two Kdo-lipids S-Kdo and Kdo-S derived from the same carbohydrate backbone and gave bicelles as their self-assembled morphology,experimental results revealed that the self-assembly showed pathway complexity.Bicelle is the thermodynamic product of S-Kdo,while for Kdo-S,the bicelle is only a kinetically trapped state,which finally transforms to a ribbon.Molecular simulation clearly revealed the different packing of Kdo-lipids in the bicelles with different contribution from hydrogen bonds and electrostatic interactions.展开更多
The intrinsic regulation of spindle orientation during asymmetric cell division depends on the evolutionarily conserved protein complex LGN(Pins)/NuMA(Mud)/GαGDP.While the role of LGN and its Drosophila orthologue Pi...The intrinsic regulation of spindle orientation during asymmetric cell division depends on the evolutionarily conserved protein complex LGN(Pins)/NuMA(Mud)/GαGDP.While the role of LGN and its Drosophila orthologue Pins is well-established,the function of AGS3,the paralogue of LGN,in spindle orientation during cell division remains controversial.This study substantiates the contentious nature of AGS3’s function through systematic biochemical characterizations.The results confirm the high conservation of AGS3 in its functional structural domains,similar to LGN,and its comparable ability to bind to partners including NuMA,Insc,and Gαi3 GDP.However,in contrast to LGN,AGS3 and the microtubule-binding protein NuMA are unable to form stable hetero-hexamers or higher-order oligomeric complexes that are pivotal for effective regulation of spindle orientation.It was found that this notable difference between AGS3 and LGN stems from the N-terminal sequence preceding the conserved TPR motifs,which spans~20 residues.Furthermore,our findings substantiate the disruptive effect of Insc on the oligomeric AGS3/NuMA complex,while showing no impact on the oligomeric LGN/NuMA complex.Consequently,Insc emerges as an additional regulatory factor that distinguishes the functional roles of AGS3 and LGN,leading to the impairment of AGS3’s ability to actively reorient the mitotic spindle.These results elucidate the molecular basis underlying the observed functional disparity in spindle orientation between LGN and AGS3,providing valuable insights into the regulation of cell division at the molecular level.展开更多
As a powerful tool for studying molecular dynamics in bioscience,single-molecule fluorescence detection providesdynamical information buried in ensemble experiments.Fluorescence in the near-infrared(NIR)is particularl...As a powerful tool for studying molecular dynamics in bioscience,single-molecule fluorescence detection providesdynamical information buried in ensemble experiments.Fluorescence in the near-infrared(NIR)is particularly usefulbecause it offers higher signal-to-noise ratio and increased penetration depth in tissue compared with visiblefluorescence.The low quantum yield of most NIR fluorophores,however,makes the detection of single-moleculefluorescence difcult.Here,we use asymmetric plasmonic nano-antenna to enhance the fluorescence intensity ofAlEE1000,a typical NIR dye,by a factor up to 405.The asymmetric nano-antenna achieve such an enhancement mainlyby increasing the quantum yield(to~80%)rather than the local field,which degrades the molecules'photostability.Our coupled-mode-theory analysis reveals that the enhancements stem from resonance-matching between antennaand molecule and,more importantly,from optimizing the coupling between the near-and far-ield modes withdesigner asymmetric structures.Our work provides a universal scheme for engineering single-molecule fluorescence inthe near-infrared regime.展开更多
Intracellular pH plays a critical role in biological functions,and abnormal pH values are related to various diseases.Here,we report on an intracellular pH sensor AgInS_(2)(AIS)/ZnS quantum dots(QDs)that show long flu...Intracellular pH plays a critical role in biological functions,and abnormal pH values are related to various diseases.Here,we report on an intracellular pH sensor AgInS_(2)(AIS)/ZnS quantum dots(QDs)that show long fluorescence lifetimes of hundreds of nanoseconds and low toxicity.Fluorescence lifetime imaging microscopy(FLIM)combined with AIS/ZnS QDs is used for the imaging of live cells in different pH buffers and different cell lines.The FLIM images of AIS/ZnS QDs in live cells demonstrate different intracellular pH values in different regions,such as in lysosomes or cytoplasm.This method can also distinguish cancer cells from normal cells,and the fluorescence lifetime difference of the AIS/ZnS QDs between the two types of cells is 100±7 ns.Most importantly,the exfoliated cervical cells from 20 patients are investigated using FLIM combined with AIS/ZnS QDs.The lifetime difference value between the normal and cervical cancer(CC)groups is 115±9 ns,and the difference between the normal and the precancerous lesion group is 64±9 ns.For the first time,the noninvasive method has been used for cervical cancer screening,and it has shown great improvement in sensitivity compared with a clinical conventional cytology examination.展开更多
基金supported by the National Natural Science Foundation of China(No.22073018,No.22377015).
文摘Intrinsically disordered proteins(IDPs)and their regions(IDRs)play crucial roles in cellular func-tions despite their lack of stable three-dimensional structures.In this study,we investigate the interac-tions between the C-terminal do-main of protein 4.1G(4.1G CTD)and the nuclear mitotic apparatus protein(NuMA)under varying pH and salt ion conditions to under-stand the regulatory mechanisms affecting their binding.4.1G CTD and NuMA bind effec-tively under neutral and alkaline conditions,but their interaction is disrupted under acidic conditions(pH 3.6).The protonation of positively charged residues at the C-terminal of 4.1G CTD under acidic conditions leads to increased electrostatic repulsion,weakening the overall binding free energy.Secondary structure analysis shows that specific regions of 4.1G CTD re-main stable under both pH conditions,but the C-terminal region(aa 990−1000)and the N-terminal region of NuMA(aa 1800−1810)exhibit significant reductions in secondary struc-ture probability under acidic conditions.Contact map analysis and solvent-accessible surface area analysis further support these findings by showing a reduced contact probability be-tween these regions under pH 3.6.These results provide a comprehensive understanding of how pH and ionic strength regulate the binding dynamics of 4.1G CTD and NuMA,emphasiz-ing the regulatory role of electrostatic interactions.
基金funded by the National Natural Science Foundation of China(32270260,32070267,32200206,32241030,and 32271245)the Taishan Scholars Project(tsqn20240516)the Shandong Provincial Natural Science Foundation,China(ZR2019ZD48 and ZR2020QC057).
文摘Photosynthetic organisms have developed various light-harvesting antenna systems to capture light and transfer energy to reaction centers(RCs).Simultaneous utilization of the integral membrane light-harvesting antenna(LH complex)and the extrinsic antenna(chlorosomes)makes the phototrophic bacterium Chloroflexus(Cfx.)aurantiacus an ideal model for studying filamentous anoxygenic phototrophs(FAPs).Here,we determined the structure of a minimal RC-LH photocomplex from Cfx.aurantiacus J-10-fl(CaRC-LH)at 3.05-Åresolution.The CaRC-LH binds only to seven LH subunits,which form a crescent-shaped antenna surrounding the movable menaquinone-10(QB)binding site of CaRC.In this complex with minimal LH units,an extra antenna is required to ensure sufficient light-gathering,providing a clear explanation for the presence of chlorosomes in Cfx.aurantiacus.More importantly,the semicircle of the antenna represents a novel RC-LH assembly pattern.Our structure provides a basis for understanding the existence of chlorosomes in Cfx.aurantiacus and the possible assembly pattern of RC-LH.
基金supported by the National Natural Science Foundation of China(62175034,62175036,32271510)the National Key R&D Program of China(2021YFF0502900)+2 种基金the Science and Technology Research Program of Shanghai(Grant No.19DZ2282100)the Shanghai Key Laboratory of Metasurfaces for Light Manipulation(23dz2260100)the Shanghai Engineering Technology Research Center of Hair Medicine(19DZ2250500).
文摘A new scheme of super-resolution optical fluctuation imaging(SOFI)is proposed to broaden its application in the high-order cumulant reconstruction by optimizing blinking characteristics,eliminating noise in raw data and applying multi-resolution analysis in cumulant reconstruction.A motor-driven rotating mask optical modulation system is designed to adjust the excitation lightfield and allows for fast deployment.Active-modulated fluorescence fluctuation superresolution microscopy with multi-resolution analysis(AMF-MRA-SOFI)demonstrates enhanced resolution ability and reconstruction quality in experiments performed on sample of conventional dyes,achieving a resolution of 100 nm in the fourth order compared to conventional SOFI reconstruction.Furthermore,our approach combining expansion super-resolution achieved a resolution at-57 nm.
基金supported by the National Key R&D Program of China(2016YFD0400106)National Natural Science Foundation of China(31630067,31671902,31401541,81671725)+1 种基金Talent Project of Zhejiang Association for Science and Technology(2018YCGC006)the 111 Project(B17039).
文摘The lignification triggered by biotic or abiotic stresses hardens fruits and vegetables and eventually influences their consumer appeal.Extensive prior efforts have been made to unveil the underlying mechanism of flesh lignification,primarily focused on its physicochemical and molecular biological properties.Nevertheless,most of these studies used destroyed and homogenized bulk tissues as analytes;as a result,potentially valuable spatial information was lost.In this study,the deposition of lignin in loquat flesh during lignification was visualized from the tissue level to the singlecell level by combining the advantages of stimulated Raman scattering(SRS)and spontaneous Raman microscopy using label-free in situ molecular imaging.SRS has the advantages of being fast and providing large-area chemical imaging to reveal the spatial heterogeneity of lignin and cell wall polysaccharide distribution in loquat flesh.After 2 days of storage at 0℃,increased lignins were observed by large-area SRS imaging.In addition,microscopic SRS images of the flesh cells indicated that the increased lignins were trapped in the cell corner(CC)and middle lamella(ML).Furthermore,the compositional and structural features of lignified cells(LCs),CC and ML of loquat flesh were investigated by spontaneous Raman microscopy,and the results showed that the LCs were a combination of lignin,cellulose,and hemicellulose,whereas CC and ML showed only deposited lignin and pectin without cross-linked cellulose and hemicellulose.This result further suggests that the lignins in the CC and ML regions of loquats were later synthesized alone during postharvest storage.This innovative combination of SRS and spontaneous Raman microscopy allows the label-free macroscale and fine chemical imaging of plant cell walls and will enhance our fundamental understanding of the structures and functions of the plant cell wall.
基金Project supported by the Key Program of the National Key Research and Development Program of China (Grant No. 2016YFA0501702)the National Natural Science Foundation of China (Grant No. 11674065)。
文摘Prion diseases are associated with the misfolding of the normal helical cellular form of prion protein (PrPC) into the β-sheet-rich scrapie form (PrPSc) and the subsequent aggregation of PrPSc into amyloid fibrils. Recent studies demonstrated that a naturally occurring variant V127 of human PrPC is intrinsically resistant to prion conversion and aggregation, and can completely prevent prion diseases. However, the underlying molecular mechanism remains elusive. Herein we perform multiple microsecond molecular dynamics simulations on both wildtype (WT) and V127 variant of human PrPC to understand at atomic level the protective effect of V127 variant. Our simulations show that G127V mutation not only increases the rigidity of the S2–H2 loop between strand-2 (S2) and helix-2 (H2), but also allosterically enhances the stability of the H2 C-terminal region. Interestingly, previous studies reported that animals with rigid S2–H2 loop usually do not develop prion diseases, and the increase in H2 C-terminal stability can prevent misfolding and oligomerization of prion protein. The allosteric paths from G/V127 to H2 C-terminal region are identified using dynamical network analyses. Moreover, community network analyses illustrate that G127V mutation enhances the global correlations and intra-molecular interactions of PrP, thus stabilizing the overall PrPC structure and inhibiting its conversion into PrPSc. This study provides mechanistic understanding of human V127 variant in preventing prion conversion which may be helpful for the rational design of potent anti-prion compounds.
基金supported by the National Key R&D Program of China(2021YFF0502900)the National Natural Science Foundation of China(62175034,62175036)+7 种基金the Anhui Province KeyR&D Project(202003a07020020)the ShanghaiNatural Science Foundation(grant No.20ZR1405100)the Science and Technology Research Program ofShanghai(grant No.19DZ2282100)the Shanghaikey discipline construction plan(2020-2022)(grantNo.GWV-10.1-XK01)the Shanghai EngineeringTechnology Research Center of Hair Medicine(19DZ2250500)the Medical Engineering Fund of Fudan University(yg2021-022)the Pioneering Project of Academy for Engineering and Technology,the Fudan University(gy2018-001,gy2018-002)the Yantai Returned Scholars'Pioneering Park.
文摘Microfuidic systems have been widely utilized in high-throughput biology analysis,but thedificulties in iquid manipulation and cell cultivation limit its application.This work has developed a new digital microfluidic(DMF)system for on-demand droplet control.By adopting anextending-depth-of-field(EDoF)phase modulator to the optical system,the entire depth of themicrofluidic channel can be covered in one image without any refocusing process,ensuring that 95%of the particles in the droplet are captured within three shots together with shaking pro-cesses.With this system,suspension droplets are generated and droplets containing only oneyeast cll can be recognized,then each single cell is cultured in the array of the chip.Byobservingtheir growth in cell numbers and the green fluorescence protein(GFP)production via fluorescence imaging,the single cell with the highest production can be identified.The results haveproved the heterogeneity of yeast cells,and showed that the combined system can be applied forrapid single-cell sorting,cultivation,and analysis.
基金the financial support from the National Natural Science Foundation of China(grant nos.51721002,21861132012,91956127,and 21975047)NSFC/China(grant nos.21674114 and 91956127)for financial supportsupported by the Shanghai Municipal Science and Technology Major Project(grant no.2018SHZDZX01)and ZJ Lab.
文摘Understanding how the diversity of glycolipids,including how their chemical structures and composition affect their biological functions,is a remarkable fundamental challenge.In this work,we employed a rare monosaccharide,3-deoxy-Dmanno-2-octulosonic acid(Kdo)to build a simple and biomimetic model to understand the diversity of glycolipids from the viewpoint of supramolecular chemistry.Kdo was chosen not only because its unusual 8-carbon acidic carbohydrate backbone is very different from common hexoses,but also because of its key structural role in lipopolysaccharides and prevalence in bacteria,plant life,and algae.It was found that although both of the two Kdo-lipids S-Kdo and Kdo-S derived from the same carbohydrate backbone and gave bicelles as their self-assembled morphology,experimental results revealed that the self-assembly showed pathway complexity.Bicelle is the thermodynamic product of S-Kdo,while for Kdo-S,the bicelle is only a kinetically trapped state,which finally transforms to a ribbon.Molecular simulation clearly revealed the different packing of Kdo-lipids in the bicelles with different contribution from hydrogen bonds and electrostatic interactions.
基金supported by grants from the National Natural Science Foundation of China(22073018 and 22377015).
文摘The intrinsic regulation of spindle orientation during asymmetric cell division depends on the evolutionarily conserved protein complex LGN(Pins)/NuMA(Mud)/GαGDP.While the role of LGN and its Drosophila orthologue Pins is well-established,the function of AGS3,the paralogue of LGN,in spindle orientation during cell division remains controversial.This study substantiates the contentious nature of AGS3’s function through systematic biochemical characterizations.The results confirm the high conservation of AGS3 in its functional structural domains,similar to LGN,and its comparable ability to bind to partners including NuMA,Insc,and Gαi3 GDP.However,in contrast to LGN,AGS3 and the microtubule-binding protein NuMA are unable to form stable hetero-hexamers or higher-order oligomeric complexes that are pivotal for effective regulation of spindle orientation.It was found that this notable difference between AGS3 and LGN stems from the N-terminal sequence preceding the conserved TPR motifs,which spans~20 residues.Furthermore,our findings substantiate the disruptive effect of Insc on the oligomeric AGS3/NuMA complex,while showing no impact on the oligomeric LGN/NuMA complex.Consequently,Insc emerges as an additional regulatory factor that distinguishes the functional roles of AGS3 and LGN,leading to the impairment of AGS3’s ability to actively reorient the mitotic spindle.These results elucidate the molecular basis underlying the observed functional disparity in spindle orientation between LGN and AGS3,providing valuable insights into the regulation of cell division at the molecular level.
基金Y.-W.T.is supported by National Natural Science Foundation of China(Nos.21773039 and 11104039)Shanghai Municipal Science and Technology Major Project(No.2018SHZDZX01)+5 种基金SCI&TECH Project(No.20ZR1405800)ZJLab.L.Zhou and Q.He are supported by National Key Research and Development Program of China(No.2017YFA0303504 and NO.2017YFA0700201)Natural Science Foundation of Shanghai(No.18ZR1403400 and NO.2020JC1414601)Fudan University-CIOMP Joint Fund(No.FC2018-006)S.Xiao is supported by the National Natural Science Foundation of China(No.11704240)Natural Science Foundation of Shanghai(17ZR1409500 and 18QA1401800)
文摘As a powerful tool for studying molecular dynamics in bioscience,single-molecule fluorescence detection providesdynamical information buried in ensemble experiments.Fluorescence in the near-infrared(NIR)is particularly usefulbecause it offers higher signal-to-noise ratio and increased penetration depth in tissue compared with visiblefluorescence.The low quantum yield of most NIR fluorophores,however,makes the detection of single-moleculefluorescence difcult.Here,we use asymmetric plasmonic nano-antenna to enhance the fluorescence intensity ofAlEE1000,a typical NIR dye,by a factor up to 405.The asymmetric nano-antenna achieve such an enhancement mainlyby increasing the quantum yield(to~80%)rather than the local field,which degrades the molecules'photostability.Our coupled-mode-theory analysis reveals that the enhancements stem from resonance-matching between antennaand molecule and,more importantly,from optimizing the coupling between the near-and far-ield modes withdesigner asymmetric structures.Our work provides a universal scheme for engineering single-molecule fluorescence inthe near-infrared regime.
基金supported by the National Natural Science Foundation of China(NSFC,Nos.62074044,61904036,and 11804350)the Medical Engineering Fund of Fudan University(No.yg2021-022)+7 种基金Zhongshan-Fudan Joint Innovation Center and Jihua Laboratory Projects of Guangdong Province(No.X190111UZ190)Fudan University-CIOMP Joint Fund(No.FC2018-001)Pioneering Project of Academy for Engineering and Technology of Fudan University(Nos.gyy2018-001 and gyy2018-002)Shanghai Natural Science Foundation(Nos.20ZR1405100 and 20ZR1403700)Science and Technology Research Program of Shanghai(No.19DZ2282100)Shanghai key discipline construction plan(2020-2022)(No.GWV-10.1-XK01)Shanghai Hong Kong,Macao,and Taiwan Cooperation Project(No.19490760900)Shanghai Engineering Technology Research Center of Hair Medicine(No.19DZ2250500).
文摘Intracellular pH plays a critical role in biological functions,and abnormal pH values are related to various diseases.Here,we report on an intracellular pH sensor AgInS_(2)(AIS)/ZnS quantum dots(QDs)that show long fluorescence lifetimes of hundreds of nanoseconds and low toxicity.Fluorescence lifetime imaging microscopy(FLIM)combined with AIS/ZnS QDs is used for the imaging of live cells in different pH buffers and different cell lines.The FLIM images of AIS/ZnS QDs in live cells demonstrate different intracellular pH values in different regions,such as in lysosomes or cytoplasm.This method can also distinguish cancer cells from normal cells,and the fluorescence lifetime difference of the AIS/ZnS QDs between the two types of cells is 100±7 ns.Most importantly,the exfoliated cervical cells from 20 patients are investigated using FLIM combined with AIS/ZnS QDs.The lifetime difference value between the normal and cervical cancer(CC)groups is 115±9 ns,and the difference between the normal and the precancerous lesion group is 64±9 ns.For the first time,the noninvasive method has been used for cervical cancer screening,and it has shown great improvement in sensitivity compared with a clinical conventional cytology examination.
