Dark-Field Microscopic Detection of Bacteria using Bacteriophage-Immobilized SiO₂@AuNP Core–Shell Nanoparticles

Abstract

To replace molecular biological and immunological methods, biosensors have recently been developed for the rapid and sensitive detection of bacteria. Among a wide variety of biological materials, bacteriophages have received increasing attention as promising alternatives to antibodies in biosensor applications. Thus, we herein present a rapid and highly selective detection method for pathogenic bacteria, which combines dark-field light scattering imaging with a plasmonic biosensor system. The plasmonic biosensor system employs bacteriophages as the biorecognition element and the aggregationinduced light scattering signal of gold nanoparticle-assembled silica nanospheres as a signal transducer. Using Staphylococcus aureus strain SA27 as a model analyte, we demonstrated that the plasmonic biosensor system detects S. aureus in the presence of excess Escherichia coli in a highly selective manner. After the sample and the S. aureus phage S13′-conjugated plasmon scattering probe were mixed, S. aureus detection was completed within 15−20 min with a detection limit of 8 × 10 4 colony forming units per milliliter.

Strategies for Surface Immobilization of Whole Bacteriophages: A Review

“…. Poly(diallyl dimethylammonium chloride) or polyDADMAC is a cationic polyelectrolyte that has been used to electrostatically bind T4 phages on paper 134 , M13 phages on glass 208 , and S13' phages on gold 71 ; in the latter case for the specific detection of S. aureus.…”

Recent Progress in the Detection of Bacteria Using Bacteriophages: A Review

“…Numerous conjugates attached to the target cell resulting in apparent aggregation causing strong light scattering. The authors reported Staphylococcus aureus' detection within 15 to 20 min with a detection limit of 8 × 10 4 CFU/mL [66].…”

Individual Plasmonic Nanoprobes for Biosensing and Bioimaging: Recent Advances and Perspectives

“…In another example, Imai and coworkers designed a plasmonic biosensor system to achieve the rapid and highly selective detection of pathogenic bacteria. [ 36 ] The stable and uniform nanoprobes were generated by the self‐assembling of AuNPs on larger SiO 2 spheres (SiO 2 @AuNPs). After the immobilization of phage S13′ on their surface, the nanoprobes specifically bound to Staphylococcus aureus through the interaction between phage S13′ and S. aureus , which greatly enhanced the light scattering intensity of S. aureus (Figure 11B).…”

“…Reproduced with permission. [ 36 ] Copyright 2019, ACS. C) Microscopic images of MCF‐7 control cells (left column) and anti‐miRNA‐21 (200 n m )‐treated cells (right column) incubated with the binary system (mixed solution of AuNP‐1 (10 µL, 0.28 n m ) and AuNP‐2 (10 µL, 0.28 n m )) for 24 h, from up to down: bright‐field images, DFM images, Cy5 fluorescence images.…”

“…The optical, chemical, and catalytic properties of nanoprobes, which are dependent on their morphology and electron density, [ 33–37 ] have fueled the design of nanoprobes for applications of PNPs ( Table 1 ). [ 38–80 ] To satisfy the different requirements for the DFM technique, a variety of nanoprobes, including gold nanoparticles (AuNPs), silver nanoparticles (AgNPs), copper nanoparticles (CuNPs), and aluminum (Al)‐based nanostructures have been synthesized.…”