A piezoelectric immunosensor for specific capture and enrichment of viable pathogens by quartz crystal microbalance sensor, followed by detection with antibody-functionalized gold nanoparticles.
A sensitive bacteria enrichment and detection system for viable Escherichia coli O157:H7 was developed using a piezoelectric biosensor-quartz crystal microbalance (QCM) with antibody-functionalized gold nanoparticles (AuNPs) used as detection verifiers and amplifiers. In the circulating-flow QCM system, capture antibodies for E. coli O157:H7 were first immobilized onto the QCM chip. The sample containing E. coli O157:H7 was circulated through the system in the presence of 10 ml of brain heart infusion (BHI) broth for 18 h. The cells of E. coli O157:H7 specifically captured and enriched on the chip surface of the QCM were identified by QCM frequency changes. Listeria monocytogenes and Salmonella Typhimurium were used as negative controls. After bacterial enrichment, detection antibody-functionalized AuNPs were added to enhance the changes in detection signal. The use of BHI enrichment further enhanced the sensitivity of the developed system, achieving a detection limit of 0-1 log CFU/ml or g. The real-time monitoring method for viable E. coli O157:H7 developed in this study can be used to enrich and detect viable cells simultaneously within 24h. The unique advantages of the system developed offer great potential in the microbial analysis of food samples in routine settings.
Department of Food Science and Human Nutrition, The University of Maine, 5735 Hitchner Hall, Orono, Maine 04473, USA.
Xiao
X
Guo
Chih-Sheng
CS
Lin
Sz-Hau
SH
Chen
Rebecca
R
Ye
Vivian C H
VC
Wu
D055910:Antibodies, Immobilized / Q000276:immunology*; D015374:Biosensing Techniques / Q000379:methods; D029798:Blueberry Plants / Q000382:microbiology*; D004927:Escherichia coli Infections / Q000175:diagnosis; D019453:Escherichia coli O157 / Q000276:immunology / Q000302:isolation & purification*; D005504:Food Analysis / Q000379:methods*; D005638:Fruit / Q000382:microbiology*; D006046:Gold / Q000737:chemistry; D006801:Humans; D007118:Immunoassay / Q000379:methods; D057230:Limit of Detection; D008089:Listeria monocytogenes / Q000276:immunology / Q000302:isolation & purification; D053758:Nanoparticles / Q000737:chemistry; D058525:Quartz Crystal Microbalance Techniques / Q000379:methods*; D012486:Salmonella typhimurium / Q000276:immunology / Q000302:isolation & purification
D055910:Antibodies, Immobilized; D006046:Gold