One-Step Fabrication of Stimuli-Responsive Chitosan-Platinum Brushes for Listeria monocytogenes Detection

Abstract

Bacterial contamination in food-processing facilities is a critical issue that leads to outbreaks compromising the integrity of the food supply and public health. We developed a label-free and rapid electrochemical biosensor for Listeria monocytogenes detection using a new one-step simultaneous sonoelectrodeposition of platinum and chitosan (CHI/Pt) to create a biomimetic nanostructure that actuates under pH changes. The XPS analysis shows the effective co-deposition of chitosan and platinum on the electrode surface. This deposition was optimized to enhance the electroactive surface area by 11 times compared with a bare platinum–iridium electrode (p < 0.05). Electrochemical behavior during chitosan actuation (pH-stimulated osmotic swelling) was characterized with three different redox probes (positive, neutral, and negative charge) above and below the isoelectric point of chitosan. These results showed that using a negatively charged redox probe led to the highest electroactive surface area, corroborating previous studies of stimulus–response polymers on metal electrodes. Following this material characterization, CHI/Pt brushes were functionalized with aptamers selective for L. monocytogenes capture. These aptasensors were functional at concentrations up to 106 CFU/mL with no preconcentration nor extraneous reagent addition. Selectivity was assessed in the presence of other Gram-positive bacteria (Staphylococcus aureus) and with a food product (chicken broth). Actuation led to improved L. monocytogenes detection with a low limit of detection (33 CFU/10 mL in chicken broth). The aptasensor developed herein offers a simple fabrication procedure with only one-step deposition followed by functionalization and rapid L. monocytogenes detection, with 15 min bacteria capture and 2 min sensing.

Research progress on detection techniques for point-of-care testing of foodborne pathogens

“… (A) The novel principles behind AuNPs optical biosensing and the schematic representation of DNA sandwich hybridization targeting ttrRSBCA locus of Salmonella spp. ( Quintela et al, 2019 ); (B) Illustration of the white light reflectance spectroscopy (WLRS) optical setup and sensing and sensing principle ( Angelopoulou et al, 2021 ); (C) Schematic diagram of electrochemical detection of E. coli O157:H7 by gold nanoparticle-catalyzed silver enhancement at porous pseudo-carbon paste electrode ( Xu et al, 2012 ); (D) Fabrication, biofunctionalization, and sensing scheme of CHI/Pt aptasensor ( Oliveira et al, 2021 ). …”

“…The target analyte can be quantified by monitoring the change of these signals. Oliveira et al (2021) developed a label-free and rapid electrochemical biosensor for LM detection using a new one-step simultaneous sonoelectrodeposition of platinum and chitosan (CHI/Pt) to create a biomimetic nanostructure that actuates under pH changes ( Figure 5D ). Actuation led to improved LM detection with a low limit of detection (33 CFU/10 ml in chicken broth).…”

“…It mainly uses antigens (antibodies), various sensitive enzymes, alkaloids, and gene sequences to detect microorganisms (Shiba 2006;Wang et al, 2013;Liu et al, 2017c;Ma et al, 2020b;Guo et al, 2021;Das and Mishra, 2022). When the sample to be tested reacts with the above substances, biological interactions will occur, which can then be converted into measurable electrical signals by signal transducers, which can be read and (Xu et al, 2012); (D) Fabrication, biofunctionalization, and sensing scheme of CHI/Pt aptasensor (Oliveira et al, 2021).…”

Context-Aware Diagnostic Specificity (CADS)

“…Examples of PON devices include detection of exposed proteins on pathogens, (e.g., SARS-CoV-2 spike protein [ 5 , 6 ]), detection of protein biomarkers [ 7 , 8 ] (e.g., cancers, cardiac diseases, autoimmune diseases, and acute events), and identification of plant pathogens in the food system (e.g., Listeria spp. invasion proteins [ 9 , 10 ]). In this special issue of Biosensors, we build on the concept of context-awareness through establishment of CADS: Context-Aware Diagnostic Specificity, an application specifically focused on diagnostics.…”

Rapid and label-free Listeria monocytogenes detection based on stimuli-responsive alginate-platinum thiomer nanobrushes

“…Comprehensive reviews on aptamer-based technologies for foodborne pathogen detection summarize recent developments in optical and electrochemical biosensors (i.e., aptasensors) 24 , 27 , 28 , including platforms that use magnetic beads conjugated to DNA aptamers and antibody-aptamer functionalized fiber-optic sensor for detection of L. monocytogenes cells from contaminated ready-to-eat meat products 29 . Hills et al 30 and Oliveira et al 31 reported a sensing mechanism for L. monocytogenes detection in food samples using the actuation of distinct chitosan-aptamer nanobrushes using the aptamer discovered by Ohk et al 29 . Recently, Sidhu et al 32 developed an aptasensor using platinum interdigitated microelectrodes functionalized with this same DNA aptamer for Listeria spp.…”