The Novel Biosensors For Rapid And Sensitive Detection Of Bacteria Based On Nanomaterials

With the increasing of clinical bacterial infection and the emergence of drug-resistant bacteria,the rapid and sensitive detection of bacteria is particularly important.The continuous development and utilization of the new nanomaterials promote a new chapter of bacterial detection and antibacterial.In clinic,new materials have been constantly adopted to realize the rapid and sensitive detection of biomarkers and the rapid development of POCT.In addition,the unique structure of bacteria also provides valuable resources for the rapid and sensitive detection of bacteria.In this paper,based on the latest research results such as clinical laboratory diagnostics,materials science and technology and bioanalytical chemistry,a series of enzyme-free bacterial detection biosensors were constructed based on electrochemical or electrochemiluminescence（ECL）platform to develop the in-depth utilization of new nanomaterials in the unique structure of bacteria,which provides a rapid,sensitive and broad-spectrum detection of pathogenic microorganisms.This research mainly includes the following three parts:1 Establishment of an electrochemiluminescence method for Staphylococcus aureus research based on MoS₂-PtNPs-VancomycinBased on AuNPs and hemin as renewable enhanced substrates of S₂O₈^2-/O₂ ECL system,and MoS₂-PtNPs as quenching agent,an"on-off"high sensitive ECL aptasensor for S.aureus detection was constructed.In this study,AuNPs can not only enhance the conductivity of electrode,but also enhance the ECL intensity of S₂O₈^2-/O₂ system through LSPR effect.In the same way,hemin can enhance the ECL intensity of S₂O₈^2-/O₂ system through the oxidation-reduction effect.The above enhancement effect makes the sensor"on".MoS₂-PtNPs-Vancomycin（MoS₂-Pt-Van）can also binds to the surface of S.aureus by the penicillin binding protein.MoS₂-PtNPs plays a quenching role by consuming the intermediate product of OOH^●.There was a linear relationship between the ECL intensity and the logarithm of S.aureus concentration in the range of 1.5×10²¹.5×10⁸CFU/mL,and the detection limit was 28 CFU/mL.In addition,this ECL aptasensor could be used for the detection of S.aureus in urine samples.Therefore,this method may become a potential application tool in medical research and early clinical diagnosis.2 Establishment of an electrochemical method for Gram-positivebacteria research based on platinum nickel copper nanocubes and peptidoglycanBased on the development of the potential application value of the special structure of bacteria,this study integrated the advantages of the Gram-positive bacterial peptidoglycan and the Pt-Ni-Cu-NCs to construct a novel non-enzyme electrochemical biosensor for bacterial detection.First of all,the electrochemical properties and peroxidase like activity of Pt-Ni-Cu-NCs were fully utilized in this study.Secondly,the purpose of this study was to develop and utilize the special function of peptidoglycan structure.Peptidoglycan has interweaved network structure and certain adhesion function,which is easy to be firmly combined with nano plane.Pt-Ni-Cu-NCs has a relatively uniform and horizontal interface.The combination of the two makes the cube stay firmly in the peptidoglycan network structure.This method had a good linear relationship in the detection range of 1.5×10² CFU/mL to 1.5×10⁸ CFU/mL and a good analytical performance（minimum detection limit:42 CFU/mL）.This method not only exploites the potential value of the peptidoglycan,but also provides a novel technical support for the detection of clinical pathogenic microorganisms and POCT.3 Establishment of an electrochemiluminescence method for broad-spectrum bacteria research based on urchin like gold nanoparticlesIn this study,the LSPR effect of the AgNPs was creatively used to enhance the ECL intensity of the S₂O₈^2-/O₂ system.In addition,Sea urchin like gold nanoparticles（SAuNPs）could puncture bacteria with its own physical structure,as well as promoting the ECL intensity of the S₂O₈^2-/O₂system by the LSPR effect.The ECL intensity reached its peak via the help of SAuNPs and AgNPs.When bacteria were added,they were punctured and bound firmly by the thorny structure on the surface of SAuNPs.The aggregation of bacteria on the electrode surface would block the transfer of electrons,thus quenching the ECL.This method was simple and rapid,and it could detect bacteria within 30 minutes with broad-spectrum detection.The proposed ECL biosensor could detect S.aureus and Escherichia coli quickly and sensitively,which achieved good linear detection within 2×10² CFU/mL to 2×10⁸ CFU/mL and lower detection limit of 52 CFU/mL.Besides,the ECL biosensor could achieve the rapid detection of bacteria in plasma.The biosensor was simple in design and sensitive in detection,which provided a scientific premise for wide-spectrum and efficient bacterial detection.In conclusion,tree kinds of biosensors were successfully constructed based on electrochemical and ECL platform.The scheme made full use of the functional characteristics of the new nanomaterials,such as chemical reaction characteristics,mimic enzyme activity,and special physical properties,as well as deeply exploring the structural characteristics of the bacteria.In addition,the utilizing of the interactions between novel nanomaterials and bacteria made the detection strategy simpler.Hence,this study provided a scientific reference for rapid and sensitive detection of clinical pathogenic microorganisms.