Nanoparticle-Enhanced Acoustic Wave Biosensor Detection of <i>Pseudomonas aeruginosa</i> in Food
A biosensor was designed for detecting <i>Pseudomonas aeruginosa</i> (<i>P. aeruginosa</i>) bacteria in whole milk samples. The sensing layer involved the antifouling linking molecule 3-(2-mercaptoethanoxy)propanoic acid (HS-MEG-COOH), which was covalently linked to an aptame...
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| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2025-02-01
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| Series: | Biosensors |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2079-6374/15/3/146 |
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| Summary: | A biosensor was designed for detecting <i>Pseudomonas aeruginosa</i> (<i>P. aeruginosa</i>) bacteria in whole milk samples. The sensing layer involved the antifouling linking molecule 3-(2-mercaptoethanoxy)propanoic acid (HS-MEG-COOH), which was covalently linked to an aptamer for binding <i>P. aeruginosa</i>. The aptasensor uses the thickness shear mode (TSM) system for mass-sensitive acoustic sensing of the bacterium. High concentrations (10<sup>5</sup> CFU mL<sup>−1</sup>) of nonspecific bacteria, <i>E. coli</i>, <i>S. aureus</i>, and <i>L. acidophilus</i>, were tested with the aptasensor and caused negligible frequency shifts compared to <i>P. aeruginosa</i>. The aptasensor has high selectivity for <i>P. aeruginosa</i>, with an extrapolated limit of detection (LOD) of 86 CFU mL<sup>−1</sup> in phosphate-buffered saline (PBS) and 157 CFU mL<sup>−1</sup> in milk. To improve the sensitivity of the sensor, gold nanoparticles (AuNPs) were functionalized with the same aptamer for <i>P. aeruginosa</i> and flowed through the sensor following bacteria, reducing the extrapolated LOD to 68 CFU mL<sup>−1</sup> in PBS and 46 CFU mL<sup>−1</sup> in milk. The frequency variations in the aptasensor are proportional to various concentrations of <i>P. aeruginosa</i> (10<sup>2</sup>–10<sup>5</sup> CFU mL<sup>−1</sup>) with and without AuNPs, respectively. The low and rapid mass-sensitive detection demonstrates the ability of the aptasensor to quantitatively identify bacterial contamination in buffer and milk. |
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| ISSN: | 2079-6374 |