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• A hollow core-shell Cu(OH) 2 @Au@Co(OH) 2 composite is prepared by a simple template-engaged reaction. • The novel structure possesses highly enzymatic activity and long-term stability for glucose detection. • The sensor achieves comparable performance with commercial glucometer in serum test. A core-shell Cu(OH) 2 @Au@Co(OH) 2 nanocomposite with hollow nano-flower morphology fabricated by a facile and non-surfactant template-engaged reaction was applied for highly sensitive detection of glucose. The prussian blue analogues (PBA) of core-shell nanocubes (CuFe@Au@CoFe) were synthesized as the template through the accurate control of the reaction rate. In this nanocubes, Au nanoparticles for accelerating electron transfer rate were reduced at the interface of CoFe (core) and CuFe (shell) to improve their conductivity. These nanocubes were then etched controllably to form three-dimensional hollow nanoflowers stacked by nanosheets. It provided abundant electrode-electrolyte channels and high surface areas for OH− and glucoses adsorption and the following reactions. Due to the sandwich structure and synergic effect of the nanomaterials, the as-prepared sensors exhibited an ultrahigh sensitivity of 3427 μA mM-1 cm-2 for glucose detection, as well as a wide linear range of 0.001–5.2 mM with a low detection limit of 0.5 μM. In addition, the Cu(OH) 2 @Au@Co(OH) 2 nanocomposite showed long-term stability and good reproducibility for glucose detection in serum with comparable results as measured with commercial glucometer. We believe the nanocomposite provided a good candidate for glucometer in future clinical applications. [ABSTRACT FROM AUTHOR]

• A flexible electrode based on Ag nanowires and MIPs was prepared. • The electrode showed high electrochemical stability upon multiple bending/twisting. • The biosensor showed high sensitivity and specificity for the detection of lactate. • The wearable sensor realized the monitoring of the human sweat lactate in vivo. We proposed a wearable electrochemical biosensor based on Ag Nanowires (AgNWs) and molecularly imprinted polymers (MIPs) prepared on the screen-printed electrode for the noninvasive monitoring of lactate in the human sweat. The MIPs were prepared by electropolymerization of 3-aminophenulboronic acid (3-APBA) with imprinted lactate molecule on the AgNWs-coated working electrode. The MIPs-AgNWs biosensor revealed high sensitivity and specificity for the detection of lactate from 10−6 M to 0.1 M, with the detection limit of 0.22 μM. Furthermore, the sensors presented high stability and reproducibility with sensitivity recovery of 99.8% ± 1.7% during 7 months storage in a dark plastic box at room temperature. In addition, the flexible electrodes also showed stable electrochemical response after been bended and twisted for 200 times, respectively. Such MIPs-AgNWs biosensor was attached on volunteers' skin for the noninvasive monitoring of the perspiration lactate in vivo. The wearable electrochemical biosensor provides feasibility in near future for the evaluation of human sweat in the military, sports and biomedical fields. [ABSTRACT FROM AUTHOR]

A paper-based colorimetric sensor array with an integrated smartphone was developed to detect a wide range of volatile organic compounds (VOCs) and used for an exhaled-breath analysis of VOCs associated with gastric cancer (GC). The sensor array combines functionalized nanoplasmonic materials and chemically responsive organic dyes which change color when they come in chemical contact with VOCs. Parts per billion (ppb)-level detection is achieved based on color changes of the array. Gas chromatography-mass spectroscopy (GC-MS) analysis of the exhaled gas from GC patients and healthy candidates indicated 25 different VOCs which may be used as the biomarkers. The paper-based smartphone nano-optoelectronic nose, used in combination with orthogonal partial least squares discriminant analysis (OPLS-DA), was able to differentiate between VOCs associated with GC patients and healthy candidates with an accuracy of 90 %. This cost-effective sensor platform paves a way for further clinical breath analysis on the noninvasive screening of GC and potentially other gas detection in medical diagnosis and environmental monitoring. • A paper-based colorimetric sensor with a smartphone is designed to detect VOCs. • The sensor array contains dyes and plasmonic materials modified with various thiols. • GC-MS analysis shows 25 VOCs as potential biomarkers for gastric cancer. • The sensor achieves the noninvasive screening of gastric cancer using exhaled gas. [ABSTRACT FROM AUTHOR]

Facile, rapid, and sensitive detection of pathogens is very crucial to control pathogen infection at its early stage. In this work, an ultrasensitive surface-enhanced Raman scattering (SERS) determination of ocular bacterial pathogens on vertically aligned gold nanowires (v-AuNWs) was proposed. The v-AuNWs substrate for the optimal SERS enhancement was obtained via optimizations of three experimental conditions, including the size and the spacing distances of seed nanoparticles, and the length of v-AuNWs, which was capable of non-labeled molecular detection and quantification, as well as bacterial analysis in clinical fluids. Furthermore, a high bacterial enrichment efficiency of up to 67% has been achieved by using a herringbone microchannel on the v-AuNWs substrate. As a result, the most common ocular bacterial pathogens, S. aureus, E. coli, P. aeruginosa, and S. epidermidis , have been discriminated on the v-AuNWs SERS platform facilitated by the partial least-squares discriminant analysis (PLS-DA) with an accuracy of 97.5%. This fast, non-labeled, and accurate bacterial sensing platform offers new possibilities for screening and control of microbial infection, especially in remote areas. [Display omitted] • Label-free SERS detection for ocular bacterial pathogens without culturing. • Vertically aligned gold nanowires (v-AuNWs) as the SERS substrate. • Bacterial classification by partial least-squares discriminant analysis method. • Spiked tears measured in a microfluidics channel with herringbone structures. [ABSTRACT FROM AUTHOR]