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Biochips are a collection of miniaturized test sites (microarrays), which enable researchers to quickly screen large numbers of biological analytes, have become one of the most promising technologies in various biomedical fields. Inspired by self-cleaning property of titanium dioxide (TiO 2 ), a renewable superwettable miRNA biochip (RSMB) was developed for specific and quantitative detection of miRNA-141. The hydrothermal synthesized TiO 2 nanowires on the fluorine-doped tin oxide (FTO) were employed as substrate and provided renewable property. Superhydrophilic microwells were spotted on the superhydrophobic TiO 2 substrate. Due to the extreme wettability difference between the microwell and surrounding substrate, the analytes could be concentrated and anchored onto the microwells from diluted solutions. Such RSMB could be renewable efficiently via photodegrading the organics on the TiO 2 substrate, and consistent results can be obtained after several cycles. This work provided an alternative tool for developing the renewable biochips and shows potential applications in the biomedical diagnosis. [ABSTRACT FROM AUTHOR]

• A target-triggered assembly strategy for Raman imaging of dual cancer biomarkers. • Two detection pathways are independent to produce strong SERS signals. • A potential tool to monitor the expression level of TE and mir-21 in different cell. Imaging multiple classes of intracellular cancer biomarkers provides invaluable insight into the tumor progression and allows cancer diagnosis at the molecular level. The challenge is to develop sensitive, selective and reliable methods for simultaneously imaging different types of cancer biomarkers at low concentrations. Herein, we demonstrated a target-triggered regioselective assembly strategy of plasmonic nanoprobes for dual Raman imaging of microRNA-21 (mir-21) and telomerase (TE) in cells. In the presence of TE, the intense signal of Raman reporter DTNB locating at the "hot spots" of end assembly probes (Au nanoparticles anchored on the terminal of Au nanorods) become weak once the TE triggers the dissociation of end assembly probes and release the DTNB-modified Au nanoparticles from the Au nanorods. Target mir-21 can trigger catalytic hairpin assembly amplification as catalysts and results in the formation of side nanoassemblies that Raman reporter Rox-modified Au nanoparticles anchored onto the side surface of Au nanorods, leading to enhancement in Rox signal. The two independent pathways can efficiently localize target analytes toward "hot spots" to produce strong, amplified SERS signals for the expression level and the dynamic change of mir-21 and TE in different cell lines, providing a potential tool for cancer diagnosis and progression monitor. [ABSTRACT FROM AUTHOR]

Levodopa (L -dopa) is an effective medication for Parkinson's disease. However, excess intake from overdose or the intake of natural sources of L -dopa can be dangerous, causing, for example, tardive dyskinesia. Therefore, in medicated individuals, it is important to monitor the levels of L -dopa in the body. In this paper, we report a simple, wearable, noninvasive, and portable metal−organic framework (MOF)-based electrochemical sensor with integrated enzymes for monitoring the concentration of levodopa in sweat, which can be used as a proxy for L -dopa levels in the body. Zeolitic imidazolate framework/graphene oxide (ZIF-8/GO) composites were prepared by the in-situ growth of ZIF-8 nanoparticles on the surface of GO, and, subsequently, tyrosinase was loaded onto the composite to yield the sensor. Integration with a wireless electronic circuit enabled communication between the sensor and a smartphone application for continuous analysis. The sensor was found to have a wide linear response range from 1 to 95 µM, a low limit of detection of 0.45 µM, satisfactory reproducibility, and excellent selectivity. In addition, the sensor showed high sensitivity and good stability as a result of the anchoring of the enzyme. Thus, the sensor shows promise for continuous, noninvasive point-of-care drug monitoring and management. • Noninvasive electrochemical sensor for levodopa determination in sweat developed. • Anchoring tyrosinase on ZIF-8/graphene oxide increases stability and active sites. • Linear electrochemical response over wide concentration range (1–95 µM). • Low limit of detection of 0.45 µM. • Continuous wireless monitoring of volunteers possible during exercise. [ABSTRACT FROM AUTHOR]

Uric acid (UA) is considered a potential risk factor in the causation or progression of kidney disease. Capabilities in personalized health monitoring enabled by capture and quantitative analysis of uric acid in the interstitial fluid could make up for the limitations of approach assessment of blood samples. Herein, we report a microfluidic−based wearable plasmonic microneedle sensor for interstitial fluid (ISF) sampling and minimally invasive uric acid monitoring. Under the force of the negative pressure generated by finger push. The hollow microneedle array could extract and deliver subcutaneous fluids to the sensing chamber by a microfluidic channel for SERS detection. The SERS sensing chip based on three-dimensional (3D) gold nanoarrays was found to have excellent reproducibility with 5.96% RSD. This high−density microarray showed ultrasensitive and label-free detection of uric acid molecules with a detection limit of 0.51 µM and enable fast identification of target molecules by integration with a handheld Raman spectrometer. The sensing platform may help bring unlimited possibilities for efficient medical healthcare and early disease prevention in daily life. • Plasmonic microneedle sensor for uric acid determination in interstitial fluid developed. • A microfluidic chip enables sampling and delivery ISF from skin by negative pressure. • Linear SERS response over wide concentration range (1 ×10−5 M to 1 ×10−3 M). • Low limit of detection of 0.51 µM. • A handheld Raman spectrometer increase the portability of testing. [ABSTRACT FROM AUTHOR]

Recent advances in biofluids monitoring have positioned urine as a non-invasive candidate for clinical diagnosis. In this paper, we employ adhesive tapes with indicator-functionalized microarrays for rapid urinalysis. Such tape-based sensor combines advantages of flexibility, adhesive and waterproof functionality in a platform, which is simply prepared by physical punching, fabrics filling and indicators modification. The simulated urine flow can be captured and penetrated in the tape-based microarrays for rapid detection of multiplexed markers such as glucose, nitrite, protein and phenylpyruvate with a smartphone-assisted colorimetric screening method. As a user-friendly point-of-care testing (POCT) approach, such tape-based sensor is ideally favorable for the early disease warning toward the patients of urinary incontinence and infants. [ABSTRACT FROM AUTHOR]