Issue 41, 2023

A rapid total bacterial count method using gold nanoparticles conjugated with an aptamer for water quality assessment

Abstract

Total bacterial count is a routine parameter in microbial safety assessment used in many fields, such as drinking water and industrial water testing. The current gold standard method for counting bacteria is the plate culture method (or heterotrophic plate count) that requires a microbiology laboratory and a long turnover time of at least 24 hours. To tackle these shortcomings, we developed a rapid total bacterial count method that relies on gold nanoparticles (AuNPs) conjugated with affinity ligands to stain bacterial cells captured on a syringe filter. Two affinity ligands were exploited, i.e. a DNA aptamer (AB2) and a lectin Griffonia simplicifolia II (GSII) that recognize bacterial cell wall commonalities, i.e. peptidoglycan and its amino sugars. Upon proper formulation with addition of a surfactant, the AB2 conjugated AuNPs (AB2–AuNPs) can selectively stain bacterial cells captured on the filter membrane with a higher sensitivity than GSII–AuNPs. Measuring the staining intensity using an in-house-built handheld detector allowed us to correlate its intensity reading with the total number of bacterial units present. This bacteria quantification method, referred to as “Filter-and-Stain”, had an efficient turnover time of 20 min suggesting its potential usage for rapid on-site applications. Additionally, the detection sensitivity provided by the AB2–AuNP nanoreagent offered a limit of detection as low as 100 CFU mL−1. We have demonstrated the use of the AB2–AuNPs for detection of bacteria from environmental water samples.

Graphical abstract: A rapid total bacterial count method using gold nanoparticles conjugated with an aptamer for water quality assessment

Supplementary files

Article information

Article type
Paper
Submitted
05 jún 2023
Accepted
20 sep 2023
First published
22 sep 2023

Nanoscale, 2023,15, 16675-16686

A rapid total bacterial count method using gold nanoparticles conjugated with an aptamer for water quality assessment

L. Sutarlie, H. L. Chee, S. Y. Ow, Z. Aabdin, W. W. Tjiu and X. Su, Nanoscale, 2023, 15, 16675 DOI: 10.1039/D3NR02635C

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements