A Versatile PdRu Bimetallic Nanoenzyme-Integrated Enzyme-Linked Immunosorbent Assay for Highly Sensitive Escherichia coli O157:H7 Detection

Abstract

Nanozymes have drawn much attention as an enzyme mimetic with low cost and stability in enhancing analytical performance. Herein, a peroxidase-mimicking nanozyme-improved enzyme-linked immunosorbent assay (ELISA) was developed employing the bimetallic PdRu nanozyme to replace the natural enzymes as a catalytic carrier for the sensing of Escherichia coli O157:H7 (E. coli O157:H7). The PdRu nanozyme displayed ultrahigh catalytic activity, possessing a catalytic rate that was 5-fold higher than horseradish peroxidase (HRP). In addition, PdRu exhibited great biological affinity with antibody (affinity constant was about 6.75 × 1012 M) and high stability. All those advantages ensure the successful establishment and the construction of a novel colorimetric biosensor for E. coli O157:H7 detection. PdRu-based ELISA not only achieved an ultrasensitive detection sensitivity (8.7 × 102 CFU/mL) by approximately 288-fold as compared to the traditional HRP-based ELISA and also possessed satisfactory specificity and reproducibility (relative standard deviation (RSD) < 10%). Furthermore, the feasibility of PdRu-ELISA was further evaluated by detecting E. coli O157:H7 in actual samples with satisfactory recoveries, indicating its potential for applications in bioassays and clinical diagnostics.

Ultrasensitive and Highly Selective Detection of Staphylococcus aureus at the Single-Cell Level Using Bacteria-Imprinted Polymer and Vancomycin-Conjugated MnO2 Nanozyme

“…This relationship is expressed by the regression equation Δ I (μA) = −0.0942 lg C S. aureus + 0.0018 ( R 2 = 0.998). By applying the 3σ/S rule, the sensor’s calculated detection limit is approximately 1 CFU mL –1 , markedly lower compared to the majority of nanozyme-based sensors, ,− as summarized in Table S1.…”

Colorimetric Detection of Escherichia coli O157:H7 via the Peroxidase-Like Activity of Aptamer-Modified Potassium/Sodium Poly(heptazine imide) Nanoparticles

“…The biosensor was compared to previously reported nanomaterial-based biosensors for the colorimetric detection of E. coli O157. − Table S6 shows that the biosensor demonstrates a superior response time over other sensors. The LOD of the biosensor is advantageous over most of the biosensors.…”

Trifunctional Nanocomposites with Colorimetric Magnetic Catalytic Activities Labels in Sandwich Immunochromatographic Detection of Escherichia coli O157:H7

“…Fortunately, the emergence of nanoenzymes has led to a flourishing development of LFIA. In nanoenzyme-based LFIA, nanoenzymes are not only used as signal generators and targets but also play a key role in sensor sensitivity and anti-interference performance through their catalytic and colorimetric abilities. − Among numerous nanozymes reported so far (including noble metals, , metal oxides, − metal–organic frameworks, − and bimetallic nanostructures − ), metal oxide nanozymes have appeared as the most efficient and promising candidates to apply in LFIA. Furthermore, plenty of methods have been developed to modulate the biosensor performance, but the current effectiveness is unsatisfactory due to the insufficient catalytic properties and poor stability of antibody loading.…”