Block-Polymer-Restricted Sub-nanometer Pt Nanoclusters Nanozyme-Enhanced Immunoassay for Monitoring of Cardiac Troponin I

Abstract

Noble-metal nanozymes have demonstrated great potential in various fields. However, aggregation of single-particle nanoparticles severely affects their exposed catalytically active sites to the extent of exhibiting weak enzyme-like activity. Here, we present an organic block surfactant (polyvinylpyrrolidone, PVP) to construct monodisperse water-stable Pt nanoclusters (Pt NCs) for an enhanced immunoassay of cardiac troponin I (cTnI). The PVP-modified Pt NC nanozyme exhibited up to 16.3 U mg–1 peroxidase-mimicking activity, which was mainly attributed to the ligand modification on the surface and the electron-absorbing effect of the ligand on the Pt NCs. The PVP-modified Pt NCs have a lower OH-transition potential, as determined by density functional theory. Under optimized experimental conditions, the enhanced nanozyme immunoassay strategy exhibited an ultrawide dynamic response range of 0.005–50 ng mL–1 for cTnI targets with a detection limit of 1.3 pg mL–1, far superior to some reported test protocols. This work provides a designable pathway for the design of artificial enzymes with high enzyme-like activity to further expand the practical range of enzyme alternatives.

Host–Guest Mechanism via Induced Fit Fullerene Complexation in Porphin Receptor to Probe Salivary Alpha-Amylase in Dental Caries for Clinical Applications

“…The results clearly demonstrate that as the concentration of α-amylase increased, the fluorescence quenching of TPPOH by starch-coated C60 was reduced. The limit of detection (LOD) was determined using the standard deviation of the obtained response and the slope of the calibration curve, which was found to be 0.001 Units/mL . A comparison of analytical parameters of the current method with some recently reported platforms is shown in Table .…”

“…The limit of detection (LOD) was determined using the standard deviation of the obtained response and the slope of the calibration curve, which was found to be 0.001 Units/mL. 57 A comparison of analytical parameters of the current method with some recently reported platforms is shown in Table 1. Although these methods can be applied for α-amylase detection, none of them have been applied for dental caries detection.…”

Integrated Sandwich-Paper 3D Cell Sensing Device to In Situ Wirelessly Monitor H2O2 Released from Living Cells

“…The current–time responses of the sensing device to H 2 O 2 were recorded every 50 s by adding 200 μM H 2 O 2 at −0.85, −0.90, and −0.95 V, respectively (Figure S7). The maximum amperometric response was obtained at a potential of −0.90 V. For real-time detection of H 2 O 2 , I – t measurements were conducted by successive adding 2 μM (Figure C), 20 μM (Figure D), and 200 μM H 2 O 2 (Figure S8) over a wide range of 2–3200 μM H 2 O 2 at an applied potential of −0.90 V. The low detection limit of the sensing device is 0.4 μM, which is calculated to be 3 times the signal-to-noise ratio. , The sensitivity of this device is 113.2 μA mM –1 cm –2 (2–20 μM), 2.6 μA mM –1 cm –2 (20–200 μM), and 1.3 μA mM –1 cm –2 (200–3200 μM) based on the surface area of the electrode and the slope of the current–dose response curve. After adding 50 μM H 2 O 2 , the fabricated sensing device reaches a steady-state current within 0.2 s, exhibiting a fast response time (Figure E).…”

Co-based metal–organic frameworks synthesized from poly(ethylene terephthalate) waste plastics for rapid detection of p-phenylenediamine

“…In the Nyquist plot, the semicircle reveals the electron transfer ability of the electrode interface, and its diameter represents the charge transfer resistance ( R ct ). 27–29 After fitting using the Randles equivalent circuit (inset, Fig. 3C), the R ct values of PPD on different electrodes are given in Fig.…”