Test-System for Bacteria Sensing Based on Peroxidase-Like Activity of Inkjet-Printed Magnetite Nanoparticles

Abstract

Rapid detection of bacterial contamination is an essential task in numerous medical and technical processes and one of the most rapidly developing areas of nano-based analytics. Here, we present a simple-to-use and special-equipment-free test-system for bacteria detection based on magnetite nanoparticle arrays. The system is based on peroxide oxidation of chromogenic substrate catalyzed by magnetite nanoparticles, and the process undergoes computer-aided visual analysis. The nanoparticles used had a pristine surface free of adsorbed molecules and demonstrated high catalytic activities up to 6585 U/mg. The catalytic process showed the Michaelis–Menten kinetic with Km valued 1.22 mmol/L and Vmax of 4.39 µmol/s. The nanoparticles synthesized were used for the creation of inkjet printing inks and the design of sensor arrays by soft lithography. The printed sensors require no special equipment for data reading and showed a linear response for the detection of model bacteria in the range of 104–108 colony-forming units (CFU) per milliliter with the detection limit of 3.2 × 103 CFU/mL.

DiZyme: Open‐Access Expandable Resource for Quantitative Prediction of Nanozyme Catalytic Activity

“…To address the need for synthesis‐by‐design approach in nanozymes development, a comprehensive database (Figure S1, Supporting Information) of >300 metal‐, bimetal‐, metal‐oxide, and nanozymes of total 67 individual compositions (Figure S2, Supporting Information) with peroxidase, oxidase and catalase activities, consisting of its fundamental element parameters as well as physicochemical characterization of nanomaterials was manually collected from >100 articles with valid data representation, material characterization, and measured activity, [ 18–20,22,30–35,54–145 ] as well as the databases with elemental properties (Table S1, Supporting Information). Catalytic activity expressed as Michaelis–Menten constant ( K m , mM) is the substrate concentration required to achieve half the maximum enzyme rate, the catalytic rate constant ( K cat , s −1 ) is the number of turns‐number of substrate molecules that each nanozyme (which concentration is expressed in µg mL −1 ) site converts into product per unit time, considering reaction rate ( V max , mM s −1 ) and the weight‐to‐volume concentration of catalyst (µg mL −1 ).…”

Intrinsic Multienzyme-like Activities of the Nanoparticles of Mn and Fe Cyano-Bridged Assemblies

“…(C,F) Dependence of the absorption on the storage time at pH 2 (red symbols) and pH 7.4 (black symbols); Figure S3: Kinetics of the ABTS substrate oxidation catalyzed by HRP; Figure S4: Study of the oxidase-like activity of the Mn-PB and PB NCPs; Figure S5: Amperometric response to hydrogen peroxide of a bare GCE at pH 3 (red line) and pH 7.4 (black line) at 0 V; Figure S6: Kinetics of the TMB substrate oxidation, 5 µg mL −1 NCPs: (A) Mn-PB and (B) PB NCPs, inserts in (A) and (B) show the corresponding Lineweaver-Burk plots; Table S1: XRD analysis of the Mn-PB NCPs and PB-NCPs; Table S2: Elemental analysis of the Mn-PB NCPs and PB NCPs by ICP-OE, MW is the mass fraction mean, and SD is the standard deviation; Table S3: Peroxidase-like properties of nanozymes with ABTS substrate. References [64][65][66][67][68][69][70] are cited in the Supplementary Materials.…”

The Influence of Magnetic Fields on Electrophoretic Processes in Magnetic Colloids with Different Stabilization Mechanisms

“…Measurements and statistical processing of the measurement results were carried out using ImageScope software created by SMA LLC (Moscow, Russia). A more detailed description of the materials may be found in previously published works [8,[54][55][56][57].…”