Escosura-Muñiz ADL, Ivanova K, Tzanov T. Electrical Evaluation of Bacterial Virulence Factors Using Nanopores.
ACS APPLIED MATERIALS & INTERFACES 2019;
11:13140-13146. [PMID:
30888786 DOI:
10.1021/acsami.9b02382]
[Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
In this work, we propose a novel methodology for electrical monitoring using nanoporous alumina membranes of virulence factors secreted by bacterial pathogens. Bacterial hyaluronidase (HYAL), which is produced by a number of invasive Gram-positive bacteria, is selected as a model compound to prove the concept. Our electrochemical setup takes advantage of the flat surface of indium tin oxide/poly(ethylene terephthalate) (ITO/PET) electrodes for their assembly with the nanoporous membrane. The proposed analytical method, based on the electrical monitoring of the steric/electrostatic nanochannels blocked upon formation of an antibody-HYAL immunocomplex, reached detection limits as low as 64 UI/mL (17.3 U/mg) HYAL. The inert surface of the ITO/PET electrodes together with the anti-biofilm properties of the 20 nm pore-sized alumina membranes allows for culturing the bacteria, capturing the secreted enzymes inside the nanochannels, and removing the cells before the electrochemical measurement. Secreted HYAL at levels of 1000 UI/mL (270 U/mg) are estimated in Gram-positive Staphylococcus aureus cultures, whereas low levels are detected for Gram-negative Pseudomonas aeruginosa (used as a negative control). Finally, HYAL secretion inhibition by RNAIII-inhibiting peptide (YSPWTNF-NH2) is also monitored, opening the way for further applications of the developed monitoring system for evaluation of the antivirulence potential of different compounds. This label-free method is rapid and cheap, avoiding the use of the time-consuming sandwich assays. We envisage future applications for monitoring of bacterial virulence/invasion as well as for testing of novel antimicrobial/antivirulence agents.
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