Single-cell adhesion studies play a crucial role in cell biology. Cell adhesion measurement methods, such as atomic force microscopy (AFM) technology, can be used to measure the single-cell adhesion force. However, these methods have many limitations, such as complex operations or the need for labeling. In this study, we proposed a miniature fiber-tip shear force probe (FSFP) that can achieve accurate measurement of the single-cell adhesion force under physiological conditions. A shear force probe structure that facilitates lateral manipulation was designed based on the principles of structural mechanics and fabricated integrally at the end face of a single-mode fiber using femtosecond laser two-photon polymerization technology. The relationship between the FSFP spectral output and the applied force was established, and its microforce sensitivity was obtained to be 2.81 nm/μN, a minimal detectable force is 7.1 nN. The achieved overall measurement range of the device is 69 μN. The adhesion force of MCF-7 breast cancer cells was measured under physiological conditions by using the FSFP. Compared to polymer substrates, the average adhesion force of cells was greater on glass substrates with greater stiffness. The average cell adhesion force value decreased by more than two times after trypsin stimulation. In addition, experiments have shown that cells tend to spread into shuttle shapes on glass substrates with greater stiffness and have a denser actin filaments distribution. To the best of our knowledge, this is the first report on the accurate measurement of the single-cell adhesion force using a miniature all-fiber microforce sensor, which is flexible, fast, and label-free, opening new avenues for single-cell analysis.

The detection of hydrogen gas in humid air environmentsis a keyunresolved challenge for hydrogen safety in the rapidly growing hydrogenenergy technologies, which hold a key to abate the CO2 emissionsfrom particularly challenging sectors that together represent morethan 20% of man-made CO2. In this work, we introduce acatalytic-plasmonic optical hydrogen sensor that employs nanofabricatedand plasmonically active Pt nanoparticles as transducer elements forhydrogen detection in highly humid environments in air. Leveragingthe combination of the Pt nanoparticles’ intrinsic high activityin the catalytic hydrogen oxidation reaction with their high sensitivityin plasmonic dielectric sensing, we show that this catalytic-plasmonicsensor is able to operate in the entire humidity range of 0–80%relative humidity accessible in our test setup and exhibits a measuredlimit of detection of 30–50 ppm hydrogen in air at 100 °Cand 80 °C sensor operating temperatures, respectively, and thatit delivers consistent and constant response to hydrogen during a143 h long continuous measurement in 80% relative humidity. We alsoshow that above a given hydrogen concentration, the sensor responsemagnitude to a specific hydrogen concentration increases with increasinghumidity, which is the distinct opposite of any other known hydrogensensing technology, whose response deteriorates or is entirely suppressedin high humidity. This advertises catalytic-plasmonic sensors as anew paradigm in the hydrogen sensor arena with particular promisefor hydrogen detection in high-humidity environments.

Precise biomolecular affinity analysis is fundamental for understanding biological processes and for drug discovery, yet current methodologies often involve high costs and operational complexity. This work introduces a novel, low-cost biomolecular detection platform that synergistically integrates meta-surface plasmon resonance (Meta-SPR) sensing with industrial machine vision for robust and accessible affinity analysis. We systematically optimized the system architecture, imaging conditions, and Meta-SPR chip design to achieve enhanced sensitivity, real-time kinetic monitoring, and user-friendliness at a significantly reduced system cost. The platform's capabilities were validated through the successful screening of affinity antibodies, effectively identifying high-affinity binders, and through detailed affinity analysis of ectodysplasin A (EDA) mutants. This analysis revealed the critical functional role of the A259E residue in EDA-EDAR (ectodysplasin A receptor) binding, and the measured affinity for wild-type trimeric EDA demonstrated high concordance with previously published data. Our results establish this integrated Meta-SPR machine vision system as a powerful, cost-effective, and versatile tool poised to democratize advanced biophysical characterization for a broader range of research and diagnostic applications.

Developing MOS-based chemiresistors with both high gas response and humidity resistance poses challenges, primarily due to the effects of water-induced surface poisoning. To address this issue, Y ions are utilized as a beneficial modifying component on p-type NiO nanofibers for constructing a triethylamine chemiresistor, leading to remarkable improvement in the performance for trace-level measurement (250 ppb). The 3Y-NiO sensor exhibits the best response to triethylamine, which is 20 times that of pure NiO nanofibers. Moreover, the sensor exhibits outstanding selectivity and long-term stability. Notably, the investigation on the influence of humidity reveals that as the content of Y3+ increases, the sensor exhibits a superior humidity resistance. Both the gas response and baseline resistance of 3Y-NiO and 5Y-NiO sensors remain almost unchanged in various humidity environments (35-80% RH). Owing to the modulation on the surface carrier concentration, the change of active oxygen species, and the hydrophobicity of the NiO surface after Y doping, the outstanding gas sensing performance and antihumidity property toward triethylamine have been simultaneously achieved. The underlying mechanisms of enhanced sensing properties and humidity resistance are analyzed by detailed characterizations and density functional theory (DFT) calculations.

We report the first infrared fluorescent protein engineered from a bilin reductase scaffold. Unlike existing near-infrared fluorescent proteins, which are derived from photoreceptor domains, our design is based on phycocyanobilin:ferredoxin oxidoreductase (PcyA), an enzyme that normally catalyzes the reduction of biliverdin (BV) to phycocyanobilin. By disabling its catalytic activity and remodeling its chromophore-binding pocket, we repurposed PcyA to stably accommodate BV as a fluorescent chromophore, generating a BV reporter with infrared output (BRIO). Finally, we demonstrated that hydrogel-encapsulated BRIO-expressing cells can serve as an inexpensive and robust platform for BV detection in biological samples. This work expands the landscape of fluorescent protein design beyond photoreceptors, demonstrating that metabolic enzymes can be reprogrammed into bright fluorescent reporters.

The construction of a highly efficient theranostics platform is of great significance for the imaging-guided tumor treatment. In this study, a multifunctional Au nanocubes-based theranostics platform was established for amplified imaging of tumor-related miRNA-21 and synergistic chemo-photothermal therapy. For this theranostics platform, doxorubicin (Dox) was loaded in the pores of multifunctional Au nanocubes (AuNCs), and the pores were subsequently blocked via DNA locks to prevent the leakage of Dox. When the multifunctional AuNCs entered in the tumor cells, the overexpressed miRNA-21 in the tumor cells specifically initiated a cyclic chain displacement reaction, opening DNA locks with high efficiency. The opening of DNA locks led to the release of Dox from the pores of AuNCs and the aggregation of AuNCs. The released Dox was utilized for fluorescence imaging and tumor chemotherapy. The aggregated AuNCs achieved photothermal conversion under near-infrared light irradiation, which was used for photothermal therapy. The miRNA-21-triggered cyclic chain displacement reaction improves the efficiency of imaging and treatment, achieving highly sensitive and selective detection of miRNA-21 with a detection limit of 233 fM. And the combination of chemotherapy and photothermal therapy efficiently kills tumor cells both in vitro and in vivo. The multifunctional AuNCs-based theranostics platform provides an effective way to diagnose cancer and treatment.

Accurate identification of multiple biomarkers in a single test is essential for early cancer diagnosis yet remains difficult with conventional wavelength- or potential-resolved methods due to signal crosstalk and background interference. To address this, we develop a novel multiplexed biosensing strategy that uses dual-mode modulation of quantum-charge-state-dependent fluorescence and spin-dependent optically detected magnetic resonance (ODMR) in nitrogen-vacancy (NV) centers within nanodiamonds. Specifically, in a sandwich bioassay on a silver nanoisland array, probes made from fluorescent nanodiamonds (FNDs) and their plasmonic counterparts (PFNDs) are distinctly modulated: silver nanoislands enhance neutral NV centers (NV0) emission from FNDs, while gold nanoparticles in PFNDs suppress NV0 and boost negative NV centers (NV-) signals. Moreover, gold nanoparticles diversify the ODMR frequencies under near-infrared excitation via photothermal effects. By leveraging these independent quantum sensing mechanisms, we simultaneously quantified three microRNAs (miRNA-155, miRNA-96, and miRNA-21) with detection limits of 1.09, 1.49, and 1.40 fM, respectively. This work advances NV center-based multiplexed biosensing and offers a highly sensitive, reproducible platform with clinical potential in early cancer diagnosis.

The development of high-performance wearable electronics demands energy harvesters that simultaneously possess exceptional power density, superior breathability, and reliable mechanical durability. To address these challenges, we report an ultralight and breathable fluorinated polyimide (FPI) nanofibrous aerogel-based hybrid nanogenerator that synergistically couples triboelectric and piezoelectric effects through a vertically integrated TENG-PENG architecture. The hybrid piezo-triboelectric nanogenerator (P-TENG) overcomes the fundamental trade-off between pressure sensitivity and electric output performance in single-mechanism devices. By synergistically combining piezoelectric and triboelectric effects, this dual-mechanism architecture simultaneously addresses the contact area-limited saturation of triboelectric output and the strain transfer-constrained piezoelectric response at low pressures. The P-TENG synergistically combines the high-voltage output of triboelectricity with the wide-range linearity of piezoelectricity, achieving exceptional electrical outputs with an open-circuit voltage of 392 V, a short-circuit current of 8.8 μA, and a power density of 898 mW·m-2. Furthermore, the FPI sensor is seamlessly integrated into a smart mask, enabling multimodal respiratory monitoring, full-body physiological sensing during sleep, and early prediction of sleep apnea. This work establishes a new paradigm for high-performance wearable systems by unifying energy harvesting and precision health monitoring.

Integrin-talin-cytoskeleton-mediated force transduction plays crucial roles in mechanobiology, especially in tumor invasion and metastasis and the regulation of neurite outgrowth and synaptic plasticity. However, gene cloning of mechanics-related protein probes remains challenging for protein gain-of-function and signal overactivation. Leveraging AlphaFold2 prediction of talin/actin-binding domains, we constructed intermolecular tension probes for talin-microfilament interactions. These probes comprised an EF domain binding on the C-terminus of talin and various actin-binding domains (SH3, PDZ, LIM, and FERM). The intermolecular domain tension probes were applied in the talin-microfilament force transduction system, which successfully avoided the adverse effects of gene cloning and talin-overactivation-induced cell invasion. We found that talin-microfilament force transduction depends on the specific actin-binding domain of talin, while the binding of microfilaments themselves is nonspecific. Microfilament depolymerization, however, can reverse the increase in tension induced by integrin activation. In this study, we developed intermolecular domain tension probes with an optimized structure and molecular weight, allowing real-time fluorescence monitoring of tension transduction and cellular distribution in live cells and force detection independent of the direct modulation of protein function.

Listeria monocytogenes (LM) causes severe foodborne illness with 20-30% mortality, which demands novel and rapid detection methods. Crucially, 3-hydroxy-2-butanone (3H2B) comprises 32.2% of the LM-emitted volatiles, serving as a specific biomarker for indirect LM monitoring. Mesoporous polydopamine (mPDA)-functionalized hollow mesoporous TiO2 nanotubes (H-mTiO2@mPDA) are rationally engineered via cooperative assembly for constructing quartz crystal microbalance gas sensors to detect 3H2B. Optimized H-mTiO2@mPDA-2 sensors demonstrate exceptional performance, including high sensitivity (6.8 Hz/ppm), rapid response/recovery (7:9 s), and outstanding selectivity. The comparative experiments against Escherichia coli and Staphylococcus aureus in ready-to-eat foods, along with practical assessments of ham and lettuce samples, illustrate the sensor's remarkable potential for LM evaluation. Moreover, morphology characterizations, Gaussian simulations, thermodynamic analysis coupled with the Clausius-Clapeyron equation, and in situ diffuse reflectance infrared Fourier-transform were synthetically utilized to study the gas sensing mechanism. It is revealed that the mesoporous structures on both TiO2 and mPDA surfaces with radial channels facilitate rapid diffusion of 3H2B and provide abundant active sites, while the hydrogen bond adsorption and Schiff base reaction between mPDA and 3H2B enhance gas-sensing efficiency and selectivity. This work pioneers an in situ monitoring paradigm for LM through synergistic material design and mechanistic innovation. Meanwhile, the established gas detection technology system exhibits significant potential for extension into environmental science, public health, and medical diagnostics.