Qiang Ma

Herein, a regenerable dielectrophoresis (DEP)-assisted microfluidic electrochemiluminescence (ECL) biosensor was developed for in situ detection of extracellular vesicles (EVs) in gastric cancer ascites. In the integrated microfluidic ECL sensor, a poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP)/deep eutectic solvent (DES)/Au NP (PDES/Au NPs) self-supporting electrode was developed. The DES treatment increased the polar β-phase proportion in PVDF-HFP and improved its conductivity. Meanwhile, Au NPs deposited on the electrode surface amplified the ECL signal of Ru(bpy)32+/TPrA@SiO2 nanobeads through the localized surface plasmon resonance (LSPR) effect and generated an inhomogeneous electric field distribution for EV capture. Due to the DEP effect, the polarized EVs migrated and enriched on the PDES/Au NP electrode surface. As a result, the isolation time of EVs was reduced from 120 to 30 min. Consequently, the sensing platform effectively captured and detected EVs in gastric cancer ascites. The detection range was 1.0 × 101.6–1.0 × 105.3 particles μL–1, and the limit of detection was 9 particles μL–1. Moreover, a regenerative strategy was designed by controllably cleaving Au–S bonds on the self-supporting electrode. This developed microfluidic ECL biosensor achieved real-time quantification of low-concentration EVs in ascites, which established a promising analytical tool for gastric cancer diagnosis as well as the discrimination of peritoneal metastatic lesions.

MicroRNA (miRNA) in plant exosomes exhibits cross-species regulatory properties, opening a new avenue for researching natural pharmacodynamic molecules. In this study, a novel biosensing system has been developed based on Zn2GeO4:Mn luminescent superparticles/Au–Ag bimetallic nanoarrays for the detection of miRNA-156a in ginseng. First, polyoxyethylene–polyoxypropylene–polyoxyethylene (PEO–PPO–PEO) triblock copolymer (P123) is used as a structure-directing agent to induce the directional self-assembly of Zn2GeO4:Mn nanorods as luminescent superparticles (SPs). Moreover, the hydrophilic end of P123 adsorbs more coreactants to accelerate reaction kinetics and significantly boosts the intensity and stability of electrochemiluminescence (ECL). Meanwhile, a Au–Ag bimetallic nanoarray is fabricated as an electrode modification interface. This Au–Ag bimetallic nanoarray enlarges the electrochemical surface area and elevates electron-transfer rates, leading to remarkable ECL signal enhancement. Furthermore, the high catalytic activity of Ag lowers the energy barrier for the electrochemical reaction in the system, thereby enabling the ECL reaction to proceed at a lower negative potential. Finally, a sandwich-type ECL biosensor is constructed for the detection of miRNA-156a in ginseng exosomes. The sensor has a linear range of 1 fM to 1 nM and a limit of detection (LOD) as low as 1.3 fM, which offers technical support for the pharmacodynamic evaluation and medicinal part selection of ginseng.

This study developed a novel electrochemiluminescence (ECL) biosensor for detecting miRNA-155, integrating polyoxometalate@metal–organic framework (POM@Cu-MOF) as a luminescent nanoprobe with a highly conductive hydrogel (PIL-Zn-SBMA) as a quasi-solid electrolyte. On the one hand, polyoxometalate was encapsulated in the Cu-MOF through host–guest interactions. Therefore, the modulated local microenvironment in POM@Cu-MOF suppressed low-energy emission and significantly improved the ECL performance of Cu-MOF. On the other hand, zwitterions formed high-speed ion-transport pathways in the PIL-Zn-SBMA hydrogel, providing excellent conductivity. The PIL-Zn-SBMA hydrogel offered an unobstructed ionic compensation pathway for the ECL process and improved the application ability and stability. As a result, the ECL reaction was accelerated, generating strong luminescence signals. Finally, based on the catalytic hairpin assembly amplification strategy, miRNA-155 was captured on the PIL-Zn-SBMA hydrogel and recognized by POM@Cu-MOF. The generated ECL signal can be used for the quantitative detection of miRNA-155 concentration in triple-negative breast cancer (TNBC) tissues within the range of 0.1 fM to 10 nM, with a detection limit of 0.1 fM. This POM@Cu-MOF/hydrogel quasi-solid electrolyte study provided a novel, reliable approach for biomarker detection in clinical diagnosis.

Interfacial energy level mismatch and inefficient charge extraction at bioelectrochemical interfaces have remained major bottlenecks for enzymatic biofuel cell-based self-powered sensing systems. Here, we reported a built-in electric field (BIEF) enabled self-powered sensing platform for intelligent dual-mode detection of 17β-estradiol (E2), featuring an energy level engineered Janus bioanode that uses work function differences to drive directional charge extraction during cascade biocatalysis. The Janus heterointerface was constructed by Zn-O-Ti coordination between unsaturated Zn²⁺ sites in ZIF-8-NH₂ and -O-terminated Ti₃C₂T_x, inducing an intrinsic BIEF and strengthened interfacial electronic coupling. Density functional theory calculations revealed favorable energy level alignment between the enzymatic redox donor FADH₂ (-4.73 eV) and the Zn-O-Ti interface (-5.11 eV), enabling low barrier electron injection and enhanced bioelectrocatalysis. For E2 sensing, an aptamer triggered hybridization chain reaction regulated methylene blue loading on the biocathode, converting target recognition into coupled electrochemical and optical outputs. The enzymatic biofuel cell was integrated on a screen-printed electrode with an IoT connected voltmeter for real-time wireless readout, while machine learning-assisted fusion improved analytical robustness in piped water, lake water, and human serum. This work highlighted Janus interfacial energy level engineering as a general strategy for regulating charge transfer in bioelectrochemical systems.