AUTHOR=Zheng Fengjiao , Wang Peixi , Du Qingfeng , Chen Yiping , Liu Nan 

TITLE=Simultaneous and Ultrasensitive Detection of Foodborne Bacteria by Gold Nanoparticles-Amplified Microcantilever Array Biosensor

JOURNAL=Frontiers in Chemistry

VOLUME=Volume 7 - 2019

YEAR=2019

URL=https://www.frontiersin.org/journals/chemistry/articles/10.3389/fchem.2019.00232

DOI=10.3389/fchem.2019.00232

ISSN=2296-2646

ABSTRACT=Foodborne pathogens, especially the bacteria are explicitly threatening public health worldwide. Biosensors represent the advances in the rapid diagnosis with highly sensitivity and selectivity. However, multiplexed analysis and minimal pre-treatment are still challenging. Here, we fabricate a gold nanoparticle (Au NP)-amplified microcantilever array biosensor which is capable of determination of ultra-low concentrations of food-borne bacteria including E. coli O157:H7, Vibrio parahaemolyticus, Salmonella, Staphylococcus aureus, Listeria monocytogenes and Shigella, etc. without germiculturing and PCR amplification which is much more rapidly than using of conventional tools. The six pairs of ssDNA probes (ssDNA1+ssDNA2 partially complementary to the target gene) derived from the sequence analysis of the specific gene of the bacteria were developed and validated. The probes of ssDNA1 were modified with -S-(CH2)6 at the 5'-end and readily to immobilize on the self-assembled monolayers (SAMs) of the sensing cantilevers in the array and couple with Au NPs, while the reference cantilevers were modified with 6-mercapto-1-hexanol SAMs to eliminate the interferences from the environment by detecting the deflection induced by nonspecific interactions. For multi-analytes sensing, the ssDNA2 labelling on the Au NPs captured the target gene sequence in the solution; and then, the Au NPs-ssDNA2-Target complex was hybridized with ssNDA1 fixed on the beam of the cantilever sensor resulting in secondary cascade amplification effect. Integrated with the enrichment of the Au NPs platform and the microcantilever array sensor detection, multiple bacteria can be rapidly and accurately detected at levels as low as 1-9 cells/mL and the working ranges were 3-4 orders of magnitude. There was virtually no cross-reaction among the various probes with different species. The approach described herein holds great potential for rapid, multiplexed and ultra-sensitive detection in food, environment, clinical and communal samples.