Dual-Functional Aerogel Assists in the Portable Biosensing

Nanoenzymes or electrocatalysts? With the accelerated revolution of material science, the emerging nanomaterials which exhibit these performances show great potential in the portable biosensing. Among these, the metallic aerogels obtain numerous attention due to their dual-functional properties.
Dual-Functional Aerogel Assists in the Portable Biosensing
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In this study, we developed the Pt-Ni hydrogels composed of the alloyed nanowires and Ni(OH)2 nanosheets, which had been demonstrated excellent peroxidase-like and electrocatalytic properties toward hydrogen peroxide (H2O2). On the basis of these characteristics, a portable dual-mode H2O2 sensor was successfully constructed (Figure 1).

Figure 1 The schematic illustration of the dual portable H2O2 biosensors based on the peroxidase-like and electrocatalytic activities of the PtNi3 hydrogelion

    The microstructures of the Pt-Ni hydrogels have been deeply investigated in our previous work (Small, 19, 2206868). In this article, we mainly explored their catalytic performances toward H2O2, especially their peroxidase-like activities. As shown in Figure 2, we engineered the component of the Pt-Ni hydrogels to find out the optimal ratio of Pt and Ni elements. Finally, the PtNi3 hydrogel was select out due to its highest affinity and catalytic activity.

Figure 2 The investigation of the peroxidase-like characteristics of the PtNix hydrogels. (A) Typical absorption spectra of the PtNi3 hydrogel; (B) the detection of OH by the fluorescence absorption spectra; (C) typical absorption spectra of the Pt, Ni, and PtNix hydrogels in 0.1 M phosphate buffer solution (PBS) (pH 5.0) with 0.5 mM TMB and 0.2 mM H2O2; (D) the absorbance peak of the Pt, Ni, and PtNix hydrogels at 652 nm; (E-F) comparisons of the Km and Kcat of the PtNix, pure Pt, Ni hydrogels and other artificial/natural enzymes

    The outstanding electrocatalytic characteristics of the PtNi3 hydrogel toward H2O2 was also demonstrated in this work. Finally, we utilized the PtNi3 dual-structure hydrogel to construct a portable biosensor which can support both the visual and electrochemical testing modes (Figure 3). Considering the importance of H2O2 analysis in the living cells, we used these two modes of portable sensor to measure the H2O2 content in the CHAPS-stimulated HeLa cells. The testing results were verified by the standard instruments, demonstrating the reliability of the developed sensing platform.

Figure 3 Diagram and application of the portable visual and electrochemical H2O2 sensors. (A-C) The schematic illustration and the corresponding calibration curve of the portable visual H2O2 sensing based on the testing paper; (D-F) the schematic illustration and corresponding calibration curve of the portable electrochemical H2O2 sensing. (G-H) the measurement of H2O2 released from the Hela cells with the portable visual and electrochemical sensors. Scale bar=1 cm; (I) the comparison of the H2O2 concentrations measured with the portable colorimetric sensor, the UV-vis spectrophotometer, the portable electrochemical sensor, and the electrochemical workstation, respectively

You can read more about our work in the article in Microsystem & Nanoengineering following the link: https://www.nature.com/articles/s41378-023-00623-y 

 

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