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Herein, a universal nucleic acid analysis platform was constructed for sensitive and accurate detection of miRNA-155 and ctDNA using isothermal amplification-assisted CRISPR/Cas12a and a tetrahedral DNA nanostructure (TDN) supported sensing interface. Under the optimal experimental conditions, the prepared sensor achieved specific detection of miRNA-155 and ctDNA at as low as aM levels in 2.6 h. Furthermore, the platform was also successfully applied to human serum sample recovery experiments and cancer cell lysates, demonstrating outstanding reliability and accuracy. We firmly believe that this work provides a universal, sensitive, and practical tool for early clinical diagnosis. [ABSTRACT FROM AUTHOR]

Developing an accurate, reliable, and stable glucose detection sensor poses a formidable challenge for the food industry. In this study, hydrothermal and wet chemical methods were employed to fabricate a Pt single-atom catalyst on Co3O4 (Co3O4/Pt SAs), where dispersed Pt atoms collaboratively catalyze the electrochemical reaction on the electrode surface. Subsequently, the integration of the microelectrode with polyethylene glycol diacrylate (PEG-DA) hydrogel and a dual-channel microfluidic chip facilitated continuous and rapid glucose detection. The addition of 5% PEG-DA hydrogel served to eliminate interference and expedite glucose detection, while the design of the dual-channel microfluidic chip generated microscale vortices, providing ample reaction opportunities for the target glucose while preventing interference from the mixing of previous and current reaction solutions. The research exhibited a favorable linear detection range from 1 to 800 μM, with a detection limit of 0.84 μM. Furthermore, validation of the device's feasibility in real samples demonstrated a glucose recovery rate ranging from 94.9 to 104.4% in beverages. [ABSTRACT FROM AUTHOR]

The development of enzyme-like electrochemical sensors with atomic-level catalytic activity sites is essential for the accurate and sensitive detection of active molecules in biological fluids. In this study, a sensitive signal amplification platform for simultaneous analysis of dopamine (DA) and uric acid (UA) was prepared on a screen-printed carbon electrode (SPCE). The sensing platform combines polypyrrole (Ppy) with high electrical conductivity and cobalt single-atom nanozymes of tubular bis-paraben nitrogen-carbon (Co-NNC) with excellent strong oxidase activity, named Ppy-Co-NNC/SPCE. The single-atom catalytic process and detection mechanism were investigated by using density functional theory. DA and UA were simultaneously detected in the ranges of 1–50 and 2–500 μM with detection limits as low as 0.025 and 0.411 μM, respectively. In addition, real-time detection of uric acid in sweat under resting and exercising conditions was achieved using a poly-(vinyl alcohol) hydrogel as a sweat collector in combination with Ppy-Co-NNC/SPCE. Moreover, the simultaneous detection of UA and DA in human urine was also achieved. The method provides a new strategy for the detection of small molecules in biofluids, which is promising for sensing and personalized medicine. [ABSTRACT FROM AUTHOR]

In-situ determination of cell-secreted biomolecules is important for elucidating its regulation of signal transduction pathways, but detecting these low-level endogenous biomolecules is difficult. Herein, using H2O2 as the detection object, we developed an ultrasensitive enzyme-free ratiometric electrochemical sensing platform in a simple and low-cost method for in-situ determination of cell-secreted H2O2, in which ferrocene (Fc) acts as an internal reference probe and nanoflower Au-Co-MOF acts a detection probe. First, flower-like CoFc-MOF was synthesized in situ on flexible carbon cloth (CC) by a one-step hydrothermal method, and then Au-CoFc-MOF/CC was obtained by electrodeposition of gold nanoparticles. The electrochemical measurement results show that the presence of H2O2 increases the reduction peak signal of Co-MOF (−0.32 V), while that of Fc (+0.4 V) is almost unchanged. By taking full advantage of the obviously separated reduction potential of Fc and Co-MOF, the well-designed sensing platform can reflect the concentration of H2O2 based on the IH2O2 – Iblank/IFc value in the 0.5 μM–10 mM range, with a detection limit as low as 32 nM, which is ∼15.6 times lower than the value obtained from the single signal method. In addition, the sensing platform also demonstrates excellent selectivity, reproducibility, stability, and biocompatibility. More significantly, this ratiometric electrochemical sensing platform based on flexible substrate shows great application potential in the in-situ determination of cell-secreted H2O2, which provides a feasible strategy for detecting other active substances released from living cells in clinical diagnosis. [ABSTRACT FROM AUTHOR]