Sensitive and reproducible FRET assays for protein biomarkers remain limited by uncontrolled donoracceptor mobility, fluorophore quenching, and batch-to-batch variability inherent to homogeneous formats. We report a two-dimensional, surface-confined FRET nanoplatform that addresses these limitations by combining a nanostructured film of fluorine-doped ZnO (F/ZnO) quantum dots with highprecision pyro-electrohydrodynamic (p-jet) microprinting. Amino-functionalized glass slides were uniformly coated with F/ZnO QDs that act as stable acceptors and optical enhancers; micrometric spots of a high-affinity peptide receptor (P52, donor) were then deposited by a LiNbO3-driven p-jet to fix donor-acceptor spacing and control surface density. This additive microfabrication strategy enforces reproducible geometry and improved photostability relative to solution assays. Optical characterization confirmed strong donoracceptor spectral overlap and robust energy transfer: P52 fluorescence was enhanced by approximately one order of magnitude on F/ZnO versus bare glass, with a linear concentration response $\left({R}^{{2}} \approx {0.99}\right)$. Co-spotting of $\text{TNF}-\alpha$ produced concentration-dependent donor quenching (up to ∼73%) and a complementary increase in F/ZnO emission (up to ∼98%), yielding quantitative readout in the ng. $\text{mL}^{-{1}}$ range and a limit of detection near $31 \text{ng} \cdot \text{mL} {-}^{{1}}$ without signal amplification. Assay specificity and resilience were evaluated by introducing representative interferents (BSA, p-Tau181) and a surrogate urine matrix; only moderate signal attenuation occurred and detectability remained within the same order of magnitude $(\text{L o D} \approx 39 \text{ng} \cdot \text{mL}-{1})$. The platform operates at room temperature, consumes minimal reagents and is compatible with scalable additive manufacturing. Monitoring $\text{TNF}-{\alpha}$ is particularly relevant for spaceflight: elevated $\text{TNF}-{\alpha}$ levels are linked to immune dysregulation and inflammation during long-duration missions. The solidsupported FRET architecture and p-jet patterning together create a practicable route toward compact point-of-care devices suitable for terrestrial and space health surveillance.

Cells are the foundation of life, and controlling their behavior is crucial for advances in medicine and biotechnology. Many current methods for cell manipulation are based on nanofabrication procedures, and hence they are limited in terms of their ability to dynamically adjust control over time and space. Here, a bio-photovoltaic interface for live cell manipulation is presented that can be activated non-invasively and remotely, demonstrating the possibility to control, to some extent, the spatial motility, the adhesion, and the morphology of the cells adhering to this interface. This platform uses a patterned light-induced electric potential in iron-doped lithium niobate crystals. The results show 80% of cells exhibiting unidirectional polarization and 50% demonstrating nuclear squeezing during dynamic real-time monitoring by a holographic microscope. The unique light-driven and reversible nature of these electric potentials, jointly with erasable and re-programmable functions, provides a dynamic and reconfigurable control on live cells. Consequently, this platform has significant potential for advancing research in cell biology and enabling innovative applications in regenerative medicine, tissue engineering, and basic cell fate research.

The detection of protein biomarkers at low concentrations through fluorescence resonance energy transfer (FRET) remains challenging, as conventional homogeneous assays are often affected by uncontrolled donor-acceptor diffusion, fluorophore quenching, and limited reproducibility. In this work, we propose a two-dimensional solid-supported FRET nanoplatform enabling a surface-confined sensing strategy for the stable and reliable detection of the model biomarker Tumor Necrosis Factor-alpha (TNF-α). The approach combines a nanostructured film of fluorine-doped ZnO (F/ZnO) quantum dots deposited on a glass slide with a high-precision pyro-electrohydrodynamic jet (p-jet) printing technique. Microspots of a high-affinity peptide (P52) were printed onto the F/ZnO layer to control donor-acceptor spacing and optimize fluorophore orientation and density, ensuring efficient FRET and reduced variability between samples. The platform provides stable, reproducible, and concentration-dependent FRET signals in the ng mL-1 range, with a limit of detection of 31 ng mL-1, suitable for identifying elevated cytokine levels associated with inflammatory responses. Assay selectivity was evaluated in the presence of non-target proteins, including bovine serum albumin (BSA) and phosphorylated Tau (p-Tau181), and in artificial urine as a complex biological matrix. The results indicate limited interference and minimal matrix effects. Overall, this strategy offers a robust architecture with low reagent consumption and scalable fabrication for future point-of-care diagnostic applications.

Conventional clinical diagnostic methods rely on specific laboratory tests, typically involving specialized medical personnel and complex equipment, which are impractical for space missions. Having intuitive, rapid, and cost-effective diagnostic devices would represent a significant asset, particularly for astronauts, who are exposed to microgravity, ionizing radiation, and other stressors that can impact their health. In this context, the present work proposes polymeric microneedles functionalized with gold nanoparticles for colorimetric sensing of the phosphorylated Tau protein, an emerging biomarker associated with neurodegenerative mechanisms in spaceflight condition. The microneedle surface was coated via a simple drop-casting method, resulting in uniform AuNP distribution. High in vitro cell viability and robust mechanical performance were observed, while a specific primary antibody enabled high analyte sensitivity. The aggregation of AuNPs upon target binding produces a visible color change from red to dark purple, demonstrating the potential for portable or smartphone-based detection. This platform represents a promising approach for rapid, on-site biomarker monitoring by astronauts during both short- and long-term missions.

HYPOTHESIS:Adsorption of amphiphilic proteins at liquid-air interfaces modifies both interfacial tension and dilatational viscoelasticity. We hypothesize that electrically triggered oscillations of picoliter droplets provide a sensitive mechanical probe of these coupled bulk-interfacial effects. EXPERIMENTS:Synthetic urine was supplemented with bovine serum albumin at concentrations from 0.0001 to 50 mg mL-1. Short electrohydrodynamic (EHD) pulses were applied to pendant picoliter droplets to induce underdamped post-jet oscillations, recorded by high-speed imaging. Oscillation frequency and decay time were extracted and interpreted using a reduced mechanical model that couples bulk viscosity with interfacial tension, dilatational elasticity, and surface viscosity. Independent pendant-drop tensiometry and step-strain dilatational rheology measurements provided surface tension and viscoelastic moduli. FINDINGS:Increasing Bovine Serum Albumin (BSA) concentration produces a monotonic decrease in both oscillation frequency and decay time. These trends reflect a reduction in surface tension and a concurrent increase in interfacial elasticity and viscosity due to protein adsorption. A single global coupling length enables quantitative agreement between measured dynamics and model predictions across regimes spanning low to high Boussinesq number. The results demonstrate that EHD-induced droplet oscillations constitute a robust, picoliter-scale method to excite and quantify interfacial viscoelasticity in protein-laden fluids. This approach provides a non-contact platform to investigate adsorption-driven interfacial mechanics in complex biofluids.

Flow cytometry (FC) offers multiparametric analysis capabilities that can quantify cellular damage after exposure to cytotoxic agents. Here, we present a comprehensive study establishing a label-free quantitative X-ray dose response profiling using a novel FC modality based on 3D Quantitative Phase Imaging, termed Holo-Tomographic Flow Cytometry (HTFC). This approach enables fully label-free 3D refractive index (RI) measurements, allowing detailed and quantitative characterization of the biophysical properties and morphology of living cells exposed to X-rays. By analyzing datasets of 3D RI tomograms from cells irradiated at graded doses, we identify intracellular biophysical markers that define a robust X-ray dose-response curve. Validation against standard clonogenic survival assays on three model cancer cell lines reveal a high correlation (>90%). HTFC not only eliminates labeling and operator bias but also markedly reduces experimental time from 1 to 2 weeks to 24 h, offering a fully automated and objective readout. While clonogenic survival remains the benchmark for radiosensitivity assessment, our findings establish HTFC as a powerful label-free platform for fast assessment of radiation damage. This technology paves the way for predictive biosensors that can capture patient-specific responses, thereby supporting the transition from conventional, uniform radiotherapy protocols to personalized treatment strategies.

An alternative method for fabricating planar surface-enhanced Raman spectroscopy (SERS) sensors, offering enhanced performance compared to conventional drop-casting techniques, is presented. We synthesized stable gold nanoparticles (AuNPs) with an average diameter of 16 ± 2 nm and developed two types of SERS sensors using pyro-electrohydrodynamic jet printing (p-jet) technology. The first sensor, printed on a glass substrate, featured a corona pattern with sensing areas aligned to the laser spot size, enabling efficient sampling with minimal material waste. The second sensor, fabricated on a dithiol-functionalized gold substrate, demonstrated uniform nanoparticle coverage. SERS activity was evaluated using p-Mercaptoaniline (pMA), yielding intense and reproducible spectra. Raman imaging confirmed consistent SERS activity, uniform nanoparticle distribution, and sensor stability. Statistical analysis indicated high reproducibility in sensor dimensions and shapes, underscoring the potential of p-jet microprinting as a cost-effective, stable, and scalable method for producing high-performance SERS sensors suitable for diverse applications.

In the era of outer space exploration, wearable and smart devices have become more important than ever before. This creates the need for quantitative fabrication of functionalized materials. From liquid film to coating, with the rapid development of manufacturing technology, the demand for real-time characterization of soft materials keeps increasing. Digital holography (DH) has been proven to be a good tool for soft matter measurements; it has been successfully applied in thin film characterization in different scenarios. Here, we demonstrate how a closed-loop manufacturing process based on DH monitoring can help to achieve the fabrication of uniform and ultrathin functionalized polymeric membranes. Thanks to the amazing full-field characterization capability of digital holography at the micrometer scale, detailed information of liquid film evolution is revealed with unprecedented precision. From the motion of liquid flows to nanoparticle clusters on membrane surfaces, holographic imaging demonstrates its inherent ability to perform non-contact, label-free measurements; this allows for continuous iteration of film functionalization process. We believe that holography-based membrane and thin liquid film forming processes will open new possibilities for advanced biomaterials.

Several studies demonstrated that the fibrillation process of β-amyloid peptides, including Aβ1-42, can be toxic at different stages. Such process is involved in the formation of plaques in the brains of patients affected by neurodegenerative diseases, such as Alzheimer's or Parkinson's disease. Therefore, detecting different stages of β-amyloid aggregation in a sample of body fluid poses a significant challenge to evaluate the stadiation of an eventual neurodegenerative pathology and hence to achieve a certain diagnosis in the very first stages of the disease. Nowadays, techniques like mass spectroscopy or analytical centrifugation are available for studying amyloid aggregations, but they remain expensive and time-consuming and hence, not suitable for routine clinical practice. Here, we show the development of a novel sensor designed to detect low abundant aggregates of Aβ1-42 in a body fluid that mimics human urine. This sensor utilizes an innovative technique that exploits the accumulation efficiency of an electric field generated by the pyroelectric effect to concentrate tiny volumes of sample onto a reaction slide. This concentration allows for the detection of the auto-fluorescent signal of the aggregates. This method, which we refer to as a 'pyro-electrohydrodynamic jet ' or p-jet, uses the intrinsic electric field of a ferroelectric material without external electrodes, resulting in a more compact and streamlined electro-hydrodynamic extraction of tiny droplets. A label-free, rapid, and sensitive classification of amyloids and their aggregation stages is achievable. Demonstrating picogram-level sensitivity for β-amyloid aggregates in urine-like samples, this method significantly outperforms common spectroscopic techniques.

Microneedles (MNs) have rapidly emerged as powerful tools in wearable biosensing, providing minimally invasive access to interstitial fluid (ISF). Among the neurodegenerative based biomarkers detectable in ISF, phosphorylated Tau at threonine 181 (p-Tau181) is reaching a clinically evaluable significance for Alzheimer's disease (AD) and other tauopathies. Elevated p-Tau181 levels are strongly correlated with abnormal Tau aggregation in the brain and with cognitive decline. Current diagnostic methods rely on invasive cerebrospinal fluid (CSF) sampling or costly laboratory immunoassays and radio-imaging which are unsuitable for routine or point-of-care screening. Here, we present a highly sensitive colorimetric microneedle-based immunosensor designed for non-invasive, transdermal detection of p-Tau181. For the first time, gold nanoparticles (AuNPs) are integrated into a three-dimensional (3D) microneedle geometry, where antibody antigen recognition occurs directly on MN in contact with ISF. The aggregation-induced optical shifts of AuNPs provide an immediate and instrument-free colorimetric signal, while two optimized coating techniques enable uniform immobilization and reproducible performance. The MN-AuNP platform achieves a limit of detection (LoD) of 16 pg/mL, a nearly 30-fold improvement compared to the reported 2D surface (460 pg/mL). This enhancement shoots from the 3D architecture, which offers greater surface area, enhanced probe loading, and improved analyte diffusion. Compared with existing diagnostic approaches, the proposed system offers multiple advantages: non-invasive operation, real-time readout without complex instrumentation, low fabrication cost, and potential integration into wearable or point-of-care formats. Collectively, these results lay the groundwork for advanced MN-based colorimetric biosensors for early Alzheimer's disease detection through accessible and patient-friendly neurodiagnostic technologies.

Fluid characterization is of paramount importance for understanding the behavior of materials in several fields, from biomedical to industrial applications. Fluidic properties, such as viscosity, provide information on fluid stability, flow behavior, and potential biomarkers of physiological conditions. In this context, this study proposes an artificial intelligence (AI)-based system to automatically retrieve rheological properties, in particular, fluid viscosity, by analyzing the fluid spatiotemporal (ST) dynamics that occur during the electrohydrodynamic (EHD) process. To this end, an ST deep learning network, based on a custom 3-D-convolutional neural network (3D-CNN), named ST-EHDeepNET, is developed to analyze sequences of frames capturing fluid droplet deformation caused by the EHD phenomena. ST-EHDeepNET simultaneously extracts spatial and temporal features from video recordings, enabling automated fluid viscosity estimation. Experimental results demonstrate the high predictive accuracy of the model root-mean-squared error (RMSE 0.1 +/- 0.02), encouraging its application in challenging industrial and clinical scenarios.

Here we demonstrate for the first time that an antibody-gold nanoparticles (AuNPs)-polymer conjugate thin-film biosensor can easily be fabricated to selectively capture Tau protein. Gold nanoparticles (AuNPs) are employed as sensing elements, thus capitalizing on their propensity to undergo assembly or disassembly in response to the adsorption or conjugation of various biomolecules on their surface, thereby forming robust interactions with the target analyte. We show that the Tau protein in its different aggregation phases can be detected, by restricting the reaction area on the solid thin polymer film and thus reducing the diffusion effects usually encountered in immunosensors. A limit of detection (LOD) of 460 pg/mL was reached, demonstrating a great potential for detecting Tau in aggregation states. This sensor based on thin polymer film could open new routes for sensing and monitoring Tau protein in biological assays and biomedical diagnosis.