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Open AccessArticle

A Convenient Colorimetric Bacteria Detection Method Utilizing Chitosan-Coated Magnetic Nanoparticles

Department of BioNano Technology, Gachon University, 1342 Seongnamdae-ro, Sujeong-gu, Seongnam, Gyeonggi 13120, Korea
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Nanomaterials 2020, 10(1), 92; https://doi.org/10.3390/nano10010092
Received: 13 December 2019 / Revised: 27 December 2019 / Accepted: 31 December 2019 / Published: 2 January 2020
An effective novel strategy to detect bacteria is promising because it may improve human health by allowing early diagnosis and timely treatment of bacterial infections. Here, we report a simple, reliable, and economical colorimetric assay using the peroxidase-like activity of chitosan-coated iron oxide magnetic nanoparticles (CS-MNPs). When CS-MNPs are incubated with a sample containing bacterial cells such as the gram-negative Escherichia coli or the gram-positive Staphylococcus aureus, the negatively-charged bacterial membrane interacts with positively-charged chitosan on the surface of CS-MNPs, thus resulting in significant reduction of their peroxidase-like activity presumably by a hindrance in the accessibility of the negatively charged substrate, 2-2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) to the positively-charged CS-MNPs. This simple colorimetric strategy allowed the rapid detection of bacterial cells down to 104 CFU mL−1 by the naked eye and 102 CFU mL−1 by spectrophotometry within 10 min. Based on the results, we anticipate that the CS-MNPs-based assay has great potential for the on-site diagnosis of bacterial infections in facility-limited or point-of-care testing (POCT) environments. View Full-Text
Keywords: colorimetric bacteria detection; chitosan-coated magnetic nanoparticles; peroxidase-like activity; Escherichia coli; Staphylococcus aureus colorimetric bacteria detection; chitosan-coated magnetic nanoparticles; peroxidase-like activity; Escherichia coli; Staphylococcus aureus
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Le, T.N.; Tran, T.D.; Kim, M.I. A Convenient Colorimetric Bacteria Detection Method Utilizing Chitosan-Coated Magnetic Nanoparticles. Nanomaterials 2020, 10, 92.

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