In Situ Tyrosinase Monitoring by Wearable Microneedle Patch toward Clinical Melanoma Screening.

Despite the potential indicating role of tyrosinase (TYR) in cutaneous melanoma, how to capture the real changes of TYR in suspicious skin remains a major challenge. Unlike the traditional human serum test, this study reports a sensing platform that incorporates a wearable microneedle (MN) patch and trimetallic Au@Ag-Pt nanoparticles (NPs) for surface-enhanced Raman scattering (SERS) and colorimetric dual-mode detecting TYR in human skin in situ toward potential melanoma screening. In the presence of TYR, catechol immobilized on MN is preferentially oxidized to benzoquinone, which competitively impedes the interaction of MN and Au@Ag-Pt NPs, triggering the SERS-colorimetric signal reciprocal switch. Using a B16F10 mouse melanoma model, our platform is capable of noninvasively piercing the skin surface and detecting TYR levels before and during anti-PD-1 antibody treatment, which would be highly informative for prognostic judgment and illness monitoring of melanoma. Through in situ sensing for capturing the metabolic changes of TYR in advance, this platform was successfully applied to discriminate the melanoma subjects from skin moles and normal ones (p < 0.001), as well as screen potential melanoma from lactate dehydrogenase (LDH)-negative patients. Melanoma growth and prognosis can still be monitored through recording the continuous change of TYR levels. More importantly, the well-defined flexible and stretchable characteristics of the MN patch allow robustly adhering to the skin without inducing chemical or physical irritation. We believe this platform integrating MN-based in situ sensing, TYR responsiveness, and SERS/colorimetric dual-readout strategy will have high clinical importance in early diagnosis and monitoring of cutaneous melanoma.

Molecularly imprinted ratiometric fluorescence detection of tetracycline based on its fluorescence enhancement effect caused by tungsten trioxide quantum dots.

This paper reports a novel probe developed based on the tungsten trioxide quantum dots (WO3-x QDs) and molecularly imprinted polymers for the detection of trace tetracycline (TC) in the complex food matrix. Tungsten ion (W6+) in WO3-x QDs has a fluorescence enhancement effect on TC, and TC has a fluorescence quenching effect on WO3-x QDs. The blue emission of the WO3-x QDs (λem = 470 nm) as a reference and the yellow emission of the TC (λem = 550 nm) as a response were utilized for the ratiometric fluorescence detection. In order to improve its selectivity, the molecular imprinting technology was combined to construct molecularly imprinted ratiometric fluorescent probes (MIRFPs). Therefore, the MIRFPs can not only selectively detect TC, but also realize the visual detection from blue to yellow. Under the optimal conditions, the linear ranges of 0.01 âˆ¼ 10.0 µmol/L and 20.0 âˆ¼ 80.0 µmol/L were obtained with the limits of detection of 3.23 nmol/L and 6.37 µmol/L, respectively. Furthermore, the MIRFPs had been successfully applied to the detection of TC in milk and eggs. The satisfactory recoveries were in the range of 92.7 âˆ¼ 102.9 % with relative standard deviations (RSD, n = 3) below 1.59 %. This work offers a good strategy for the detection of food hazards.