Rapid,sensitive,point-of-care detection of pathogenic bacteria is important for food safety.In this study,we developed a novel quantum dot nanobeads-labelled lateral flow immunoassay strip(QBs-labelled LFIAS)combined ...Rapid,sensitive,point-of-care detection of pathogenic bacteria is important for food safety.In this study,we developed a novel quantum dot nanobeads-labelled lateral flow immunoassay strip(QBs-labelled LFIAS)combined with strand displacement loop-mediated isothermal amplification(SD-LAMP)for quantitative Salmonella Typhimurium(ST)detection.Quantum dot nanobeads(QBs)served as fluorescence reporters,providing good detection efficiency.The customizable strand displacement(SD)probe was used in LAMP to improve the specificity of the method and prevent by-product capture.Detection was based on a sandwich immunoassay.A fluorescence strip reader measured the fluorescence intensity(FI)of the test(T)line and control(C)line.The linear detection range of the strip was 10^(2)–10^(8) colony forming units(CFU)·mL^(-1).The visual limit of detection was 10^(3) CFU·mL^(-1),indicating that the system was ten-fold more sensitive than AuNPs-labelled test strips.ST specificity was analyzed in accordance with agarose gel outputs of polymerase chain reaction(PCR)and SD-LAMP.We detected ST in foods with an acceptable recovery of 85%–110%.The method is rapid,simple,almost equipment-free,and suitable for bacterial detection in foods and for clinical diagnosis.展开更多
Virus is a kind of microorganism and possesses simple structure and contains one nucleic acid,which must be replicated using the host cell system.It causes large-scale infectious diseases and poses serious threats to ...Virus is a kind of microorganism and possesses simple structure and contains one nucleic acid,which must be replicated using the host cell system.It causes large-scale infectious diseases and poses serious threats to the health,social well-being,and economic conditions of millions of people worldwide.Therefore,there is an urgent need to develop novel strategies for accurate diagnosis of virus infection to prevent disease transmission.Quantum dots(QDs)are typical fluorescence nanomaterials with high quantum yield,broad absorbance range,narrow and size-dependent emission,and good stability.QDs-based nanotechnology has been found to be effective method with rapid response,easy operation,high sensitivity,and good specificity,and has been widely applied for the detection of different viruses.However,until now,no systematic and critical review has been published on this important research area.Hence,in this review,we aim to provide a comprehensive coverage of various QDs-based virus detection methods.The fundamental investigations have been reviewed,including information related to the synthesis and biofunctionalization of QDs,QDs-based viral nucleic acid detection strategies,and QDs-based immunoassays.The challenges and perspectives regarding the potential application of QDs for virus detection is also discussed.展开更多
It is extremely important for bacteria detection in many fields,such as medical diagnosis and food safety.In this paper,streptavidin functionalized quantum dots(SA-QDs),as a nano-fluorescent probe,were used to attach ...It is extremely important for bacteria detection in many fields,such as medical diagnosis and food safety.In this paper,streptavidin functionalized quantum dots(SA-QDs),as a nano-fluorescent probe,were used to attach with Escherichia coli(E.coli) for the detection and identification of bacteria with immunoreactions and biotin-streptavidin affinity.Fluorescent images of the bacteria and the fluorescence intensity were used to evaluate the conjugation effect with different incubation time.Our results showed that 20 min is a reasonable incubation time for the SA-QDs coupling to E.coli cells.The fluorescent images,which produce a greatly amplified and enhanced signal of E.coli cells,were obtained through the immunological amplification and fluorescent probe enrichment steps.In addition,the bleaching process of SA-QDs without any encapsulation at room temperature was clearly observed during 10 min of being excited.Our work provided a modularized sample treatment method using SA-QDs as a nano-fluorescent probe in cellular imaging and bio-labeling.展开更多
A lateral flow immunoassay(LFA)biosensor that allows the sensitive and accurate identification of severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)and other common respiratory viruses remains highly desired ...A lateral flow immunoassay(LFA)biosensor that allows the sensitive and accurate identification of severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)and other common respiratory viruses remains highly desired in the face of the coronavirus disease 2019 pandemic.Here,we propose a multiplex LFA method for the on-site,rapid,and highly sensitive screening of multiple respiratory viruses,using a multilayered film-likefluorescent tag as the performance enhancement and signal amplification tool.This film-like three-dimensional(3D)tag was prepared through the layer-by-layer assembly of highly photostable CdSe@ZnS-COOH quantum dots(QDs)onto the surfaces of monolayer graphene oxide nanosheets,which can provide larger reaction interfaces and specific active surface areas,higher QD loads,and better luminescence and dispersibility than traditional spherical fluorescent microspheres for LFA applications.The constructedfluorescent LFA biosensor can simultaneously and sensitively quantify SARS-CoV-2,influenza A virus,and human adenovirus with low detection limits(8 pg/mL,488 copies/mL,and 471 copies/mL),short assay time(15 min),good reproducibility,and high accuracy.Moreover,our proposed assay has great potential for the early diagnosis of respiratory virus infections given its robustness when validated in real saliva samples.展开更多
基金This work was supported by the National Key Research and Development Program of China(2019YFC1606300)the Local Innovative and Research Teams Project of Guangdong Pearl River Talents Program(2017BT01S174)the Guangdong Academy of Sciences Special Project of Implementing Innovation-Driven Development Capacity Building(2018GDASCX-0401).
文摘Rapid,sensitive,point-of-care detection of pathogenic bacteria is important for food safety.In this study,we developed a novel quantum dot nanobeads-labelled lateral flow immunoassay strip(QBs-labelled LFIAS)combined with strand displacement loop-mediated isothermal amplification(SD-LAMP)for quantitative Salmonella Typhimurium(ST)detection.Quantum dot nanobeads(QBs)served as fluorescence reporters,providing good detection efficiency.The customizable strand displacement(SD)probe was used in LAMP to improve the specificity of the method and prevent by-product capture.Detection was based on a sandwich immunoassay.A fluorescence strip reader measured the fluorescence intensity(FI)of the test(T)line and control(C)line.The linear detection range of the strip was 10^(2)–10^(8) colony forming units(CFU)·mL^(-1).The visual limit of detection was 10^(3) CFU·mL^(-1),indicating that the system was ten-fold more sensitive than AuNPs-labelled test strips.ST specificity was analyzed in accordance with agarose gel outputs of polymerase chain reaction(PCR)and SD-LAMP.We detected ST in foods with an acceptable recovery of 85%–110%.The method is rapid,simple,almost equipment-free,and suitable for bacterial detection in foods and for clinical diagnosis.
基金supported by National Key Research and Development Program of China(2021YFA0910900)the National Natural Science Foundation of China(32222044,22104147)+5 种基金Shenzhen Municipal Science and Technology Innovation Council(RCYX20210609103823046)Youth Innovation Promotion Association CAS(2021359)Natural Science Foundation of Guangdong(2020A1515111130)Guangdong Provincial Key Laboratory of Synthetic Genomics(2019B030301006)Shenzhen Science and Technology Program(KQTD20180413181837372)Shenzhen Outstanding Talents Training Fund.
文摘Virus is a kind of microorganism and possesses simple structure and contains one nucleic acid,which must be replicated using the host cell system.It causes large-scale infectious diseases and poses serious threats to the health,social well-being,and economic conditions of millions of people worldwide.Therefore,there is an urgent need to develop novel strategies for accurate diagnosis of virus infection to prevent disease transmission.Quantum dots(QDs)are typical fluorescence nanomaterials with high quantum yield,broad absorbance range,narrow and size-dependent emission,and good stability.QDs-based nanotechnology has been found to be effective method with rapid response,easy operation,high sensitivity,and good specificity,and has been widely applied for the detection of different viruses.However,until now,no systematic and critical review has been published on this important research area.Hence,in this review,we aim to provide a comprehensive coverage of various QDs-based virus detection methods.The fundamental investigations have been reviewed,including information related to the synthesis and biofunctionalization of QDs,QDs-based viral nucleic acid detection strategies,and QDs-based immunoassays.The challenges and perspectives regarding the potential application of QDs for virus detection is also discussed.
基金Sponsored by the Knowledge Innovation Program of the Chinese Academy of Sciences (KGCX2-YW-111-2)the National Hi-Tech Research and Development Program of China (Grant No. 2007AA03Z428)National Natural Science Foundation of China (Grant No. 60801032)
文摘It is extremely important for bacteria detection in many fields,such as medical diagnosis and food safety.In this paper,streptavidin functionalized quantum dots(SA-QDs),as a nano-fluorescent probe,were used to attach with Escherichia coli(E.coli) for the detection and identification of bacteria with immunoreactions and biotin-streptavidin affinity.Fluorescent images of the bacteria and the fluorescence intensity were used to evaluate the conjugation effect with different incubation time.Our results showed that 20 min is a reasonable incubation time for the SA-QDs coupling to E.coli cells.The fluorescent images,which produce a greatly amplified and enhanced signal of E.coli cells,were obtained through the immunological amplification and fluorescent probe enrichment steps.In addition,the bleaching process of SA-QDs without any encapsulation at room temperature was clearly observed during 10 min of being excited.Our work provided a modularized sample treatment method using SA-QDs as a nano-fluorescent probe in cellular imaging and bio-labeling.
基金supported by the National Natural Science Foundation of China(Nos.81830101 and 32200076)the National Science and Technology Major Project for Infectious Diseases Control(Nos.2018ZX10712001-010 and 2018ZX10101003-001)+1 种基金the Natural Science Foundation of Anhui Province(No.2208085MB29)The authors would like to thank Prof.Chengfeng Qin from Beijing Institute of Microbiology and Epidemiology for providing inactivated SARS-CoV-2 virions,and thank Ms.Le Zhao of National Center for Nanoscience and Technology for helping to conduct SEM analysis.
文摘A lateral flow immunoassay(LFA)biosensor that allows the sensitive and accurate identification of severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)and other common respiratory viruses remains highly desired in the face of the coronavirus disease 2019 pandemic.Here,we propose a multiplex LFA method for the on-site,rapid,and highly sensitive screening of multiple respiratory viruses,using a multilayered film-likefluorescent tag as the performance enhancement and signal amplification tool.This film-like three-dimensional(3D)tag was prepared through the layer-by-layer assembly of highly photostable CdSe@ZnS-COOH quantum dots(QDs)onto the surfaces of monolayer graphene oxide nanosheets,which can provide larger reaction interfaces and specific active surface areas,higher QD loads,and better luminescence and dispersibility than traditional spherical fluorescent microspheres for LFA applications.The constructedfluorescent LFA biosensor can simultaneously and sensitively quantify SARS-CoV-2,influenza A virus,and human adenovirus with low detection limits(8 pg/mL,488 copies/mL,and 471 copies/mL),short assay time(15 min),good reproducibility,and high accuracy.Moreover,our proposed assay has great potential for the early diagnosis of respiratory virus infections given its robustness when validated in real saliva samples.
