Hollow NiCo@C Nanozyme-Embedded Paper-Based Colorimetric Aptasensor for Highly Sensitive Antibiotic Detection on a Smartphone Platform

Abstract

Antibiotic residues in the environment and in foods pose a serious threat to ecosystems and human health. Developing sensitive and on-site detection methods is therefore in high demand. In this work, a portable paper-based colorimetric sensor with a smartphone platform with an ultrahigh sensitivity has been designed for on-site and quantitative analysis of antibiotic residues based on aptamer-regulated nanozyme activity. The developed excellent peroxidase-like nanozymes, carbon-protected NiCo bimetal oxides with a unique hollow nanocage structure (NiCo@C HCs), could effectively catalyze the oxidation of chromogenic substrates by H2O2. Once bound to a specific aptamer, the enzyme-mimicking activity of NiCo@C HCs is obviously inhibited as a result of the masking of active sites but could be restored via the target-aptamer recognition. Herein, the aptamer-modified NiCo@C HCs are embedded on paper pieces to construct paper-based biochips for visual detection. Meanwhile, a smartphone platform is integrated for the signal readout. Using enrofloxacin (ENR) as an analyte model, the proposed paper-based analysis platform shows a reliable and sensitive detection of ENR with an ultralow detection limit of 0.029 ng/mL. The platform also works well in various real samples. This analysis method is facile in design, showing a great application potential for on-site and mass screening of antibiotic residues in the environment and in foods.

Portable Hydrogel Kits Made with Bimetallic Nanozymes for Point-of-Care Testing of Perfluorooctanesulfonate

“…30 The O 1s spectrum revealed three distinct peaks at 531.73 eV, indicative of metal− oxygen bonds, as shown in Figure S3. 31 These results validate the successful synthesis of CuCo-PBA NBs. Similarly, CuMn-PBA NBs were characterized using XRD, scanning electron microscopy (SEM), TEM, and XPS, with results presented in Figures S4−S6.…”

“…Additionally, the Co 2p spectrum was deconvoluted into four peaks with binding energies of 786.07 and 803.36 eV corresponding to Co 2+ and 796.69 and 781.49 eV associated with Co 3+ , as illustrated in Figure m . The O 1s spectrum revealed three distinct peaks at 531.73 eV, indicative of metal–oxygen bonds, as shown in Figure S3 . These results validate the successful synthesis of CuCo-PBA NBs.…”

Nanozymes: powerful catalytic materials for environmental pollutant detection and degradation

“…to establish aptasensors or immunoassays for antibiotics. [141][142][143][144][145][146][147][148][149] Zhu and co-workers designed a paper colorimetric sensor using aptamer-regulated nanozyme activity for in-field determination of enrofloxacin (ENR). 149 Carbon-protected hollow NiCo bimetal oxide nanocages (NiCo@C HCs) were prepared through one-step pyrolysis of a NiCo-Prussian blue analog coated by polydopamine (NiCo-PBA@PDA).…”

“…[141][142][143][144][145][146][147][148][149] Zhu and co-workers designed a paper colorimetric sensor using aptamer-regulated nanozyme activity for in-field determination of enrofloxacin (ENR). 149 Carbon-protected hollow NiCo bimetal oxide nanocages (NiCo@C HCs) were prepared through one-step pyrolysis of a NiCo-Prussian blue analog coated by polydopamine (NiCo-PBA@PDA). Benefitting from the carbonprotected structure and the synergistic impact of bimetal oxides, the material exhibited good peroxidase-mimetic ability in catalyzing the oxidation of TMB by H 2 O 2 .…”

When nanozymes meet deoxyribonucleic acid: Understanding their interactions and biomedical diagnosis applications

“…In contrast, physical adsorption of ssDNA can also reduce the activity of some nanozymes. 38,40,[60][61][62][63][64][65][66][67][86][87][88][89][90][91][92][93][94][95][96][97][98][99][100][101][102][103] It is generally considered that the adsorption of DNA chains (aptamers) covers some surfaces of nanomaterials, and the shielding of active sites causes the decrease in their enzyme-like catalytic activity. At the very beginning, Bansal's group observed that AuNPs exhibited the PODlike activity originating from the interaction of their surface with the POD substrate TMB.…”