Dalian Polytechnic University

A rapidly growing field is piezoresistive sensor for accurate respiration rate monitoring to suppress the worldwide respiratory illness. However, a large neglected issue is the sensing durability and accuracy without interference since the expiratory pressure always coupled with external humidity and temperature variations, as well as mechanical motion artifacts. Herein, a robust and biodegradable piezoresistive sensor is reported that consists of heterogeneous MXene/cellulose-gelation sensing layer and Ag-based interdigital electrode, featuring customizable cylindrical interface arrangement and compact hierarchical laminated architecture for collectively regulating the piezoresistive response and mechanical robustness, thereby realizing the long-term breath-induced pressure detection. Notably, molecular dynamics simulations reveal the frequent angle inversion and reorientation of MXene/cellulose in vacuum filtration, driven by shear forces and interfacial interactions, which facilitate the establishment of hydrogen bonds and optimize the architecture design in sensing layer. The resultant sensor delivers unprecedented collection features of superior stability for off-axis deformation (0–120°, ~ 2.8 × 10–3 A) and sensing accuracy without crosstalk (humidity 50%–100% and temperature 30–80 °C). Besides, the sensor-embedded mask together with machine learning models is achieved to train and classify the respiration status for volunteers with different ages (average prediction accuracy ~ 90%). It is envisioned that the customizable architecture design and sensor paradigm will shed light on the advanced stability of sustainable electronics and pave the way for the commercial application in respiratory monitory.

The engineering of the nanozyme interface is crucial for manipulating their catalytic efficacy, yet achieving this through chirality modulation still remains a significant challenge. In this work, a chirality-driven interface engineering strategy by constructing chiral L/D‑copper oxide hierarchical architectures (L/D-CuO) via a facile one-step wet-chemistry method using enantiomeric cysteine ligands. The resulting hierarchical architectures feature flower-like architectures, and more importantly exhibit intense and chiroptical activity, unambiguously confirming the successful creation of a tailored chiral interface. Steady-state kinetic analyses revealed that the engineered chiral interface significantly augmented the peroxidase-like (POD-like) activity. The L-CuO demonstrated a lower Michaelis-Menten constant (Km = 1.003 mM) and a higher maximal reaction rate (Vm = 0.0252 μM·s^-1) compared to achiral CuO (Km = 1.38 mM, Vm = 0.0185 μM·s^-1), indicating enhanced substrate affinity and catalytic efficiency at the interface. This augmented interfacial catalysis was effectively translated into potent antibacterial action. The L-CuO achieved a bacterial inhibition rate reaching 90.2% against E. coli and 93.1% against S. aureus, compared with only 59.3% for E. coli and 66.9% for S. aureus antibacterial efficacy for achiral CuO. In practical fruit preservation, the chiral hierarchical architectures effectively functioned as an interfacial antimicrobial coating, significantly preserving fruit quality by inhibiting surface microbial spoilage. This work highlights the profound impact of chirality-driven interface engineering on nanozyme functionality and provides a foundational strategy for designing advanced interfacial catalysts for antibacterial and other biomedical applications.

Hydrogenobyrinic acid (HBA) is a pivotal intermediate in the aerobic biosynthesis of cobalamin (vitamin B12), representing a stable, metal-free corrin precursor and a useful substrate for both biological and chemical derivatization. Despite its significance, efficient HBA production remains limited by the complexity of the native cobalamin pathway, which involves more than 30 enzymatic steps and tightly regulated gene clusters. In this study, we combined in vivo metabolic engineering and in vitro multienzyme screening to design, optimize, and validate an artificial HBA operon. A systematic strategy was employed to identify pathway bottlenecks by tuning ribosome-binding sites and introducing isoenzymes in Escherichia coli, followed by cell-free prototyping to further analyze and enhance catalytic steps. Integration of the two approaches revealed that the downstream enzymes CobF, CobK, CobL, and CobH are critical determinants of HBA yield. Guided by this insight, we constructed an optimized artificial operon (FKLHIGJM), which demonstrated superior performance both in whole-cell fermentation and in cell-free systems. Furthermore, we established a simple and efficient HBA biosynthetic platform in vitro using crude cell extracts derived from our optimized HBA operon, achieving an HBA titer of 37.01 ± 0.94 μM (32.59 ± 0.83 mg/L) HBA within 12 h. This performance represents a 12.2-fold improvement over the titer obtained with the originally designed operon in our initial cell-free system, and a 214.5-fold enhancement compared with the titer produced by recombinant E. coli fermentation using the originally designed operon. This work highlights the value of coupling metabolic engineering with cell-free strategies to advance artificial pathway design and sustainable cobalamin precursor production.