Hong Qun Luo

Untreated metallurgical wastewater contains various heavy metal ions M ^x+ (such as Fe ³⁺ , Co ²⁺ , Ni ²⁺ , and Cu ²⁺ ). Traditional treatment methods usually involve energy‐intensive separation and resynthesis steps. To address this issue, this work proposes the in situ reconstruction of metal ions from the wastewater into self‐adaptive catalysts (MO _y H _z /VNO _x ) during the hydrogen evolution reaction (HER), which actively adapt to the HER environment. After reconstruction, trace residual metal species also modulate catalytic activity. Among the obtained catalysts, β‐Co(OH) ₂ /VNO _x shows the best HER activity, with Co─O─V as the active center. Theoretical calculations reveal that β‐Co(OH) ₂ tunes the electronic structure of VNO _x , weakening H ^* adsorption and lowering the H ₂ O dissociation barrier. Thus, β‐Co(OH) ₂ /VNO _x reduces the overpotential ( η ) at −10 mA cm ⁻² by 268 and 301 mV compared to β‐Co(OH) ₂ and VNO _x , respectively. This work offers an eco‐friendly strategy for simultaneous metal recovery and hydrogen production, with potential applications in energy transformation and environmental cleanup.

Cancer incidence is high worldwide, and early treatment can reduce mortality rates. Circulating tumor DNA (ctDNA) serves as a biomarker for liquid biopsy, enabling early monitoring of tumor burden and treatment response. DNA nanobiosensors have become an important tool for detecting ctDNA due to their high efficiency and low cost. In this study, we developed a DNA lever nanomachine (DLN) based on a catalytic hairpin assembly (CHA)-driven conformational transition for the sensitive detection of ctDNA. The principle is to combine the CHA reaction with DNA lever-based mechanical amplification, enabling the detection of target ctDNA by monitoring changes in signal intensity. During the initial preparation stage, the nanomachine remains in a fluorescence-quenched state. When target ctDNA is present, CHA is activated, triggering downstream signal transduction and initiating a synergistic process of “target capture-conformational transition-signal amplification”, ultimately leading to the restoration and amplification of the fluorescence signal. Additionally, by adjusting the fulcrum position, this machine enhances mechanical efficiency through an effort-saving lever mechanism. It minimizes internal driving force requirements by optimizing the torque load value at the load end, thereby further improving system responsiveness. The established fluorescent biosensing platform achieves satisfactory linear correlation with ctDNA concentrations ranging from 1 pM to 100 nM, with a limit of detection of 0.776 pM. This method offers a new strategy for CHA-based DNA mechanical fluorescence sensing and holds significant application potential in biological sample detection.

Nanoplastics, as an emerging class of pervasive environmental contaminants with high bioaccumulation potential, pose serious detection challenges due to their small size, chemical inertness, and interference from complex sample matrices, necessitating innovative sensing strategies with enhanced sensitivity and selectivity. Here, we report a highly sensitive and selective iontronic sensor based on polydopamine-modified graphene oxide (pGO) nanochannels for the detection of polystyrene (PS) nanoplastics. DNA aptamers specific to PS are immobilized on the pGO surface via π–π interactions, forming a duplex structure with an anchor strand. Upon PS binding, the aptamer undergoes conformational change, exposing a downstream sequence that initiates guanine nanowire (G-wire) formation through hybridization with complementary DNA strands in the presence of K⁺ and Mg²⁺ ions. This G-wire supramolecular assembly significantly amplifies the interfacial charge density, resulting in a robust iontronic current response. The sensor exhibits excellent analytical performance with a wide linear detection range (10–10⁶ ng/L) and an ultra-low detection limit of 1.493 ng/L. It demonstrates high specificity in the presence of common environmental interferents and retains robust performance in aged plastic samples. This platform integrates aptamer specificity, graphene nanofluidic ion transport, and DNA nanostructure-based amplification, providing a scalable, low-cost, and precise strategy for nanoplastic monitoring in complex environmental matrices.

The geometric chirality of nanoscale materials originates from the asymmetric structures of the enantiomeric molecules. Herein, we introduce a universal strategy for fabricating in situ-synthesized Au nanostructures (issAu) on biological substrates using a simple staining solution of Au precursors, surfactant, and reductant. As a proof-of-concept, we integrated this staining reaction into bacterial systems, achieving the oriented growth of issAu on organism skeletons. With the involvement of exogenous cysteine enantiomers in the staining solution, enantiomeric molecules contribute to anisotropic growth of branched issAu and the evolution of plasmonic chirality. Through reaction optimization, we successfully engineer chiral issAu onto bacteria, constructing these nanobioheterostructures as versatile, bacterium-derived nanomaterials. The simple and rapid staining method based on chiral issAu growth solutions facilitates the in situ plasmonic engineering of pathogenic bacteria, enabling optical microscopy imaging of individual microbes. Our protocol provides an approach for the chiral nanoengineering of biological entities and exhibits high potential in antimicrobial and bioanalytical applications.