Abstract The real-time, in vivo measurement of drugs, metabolites, and biomarkers in awake animals could enable unprecedented insights into metabolic regulation, pharmacokinetics, pharmacodynamics, and behavioral response. In pursuit of this vision, here we demonstrate a subcutaneous electrochemical aptamer-based (EAB) sensor architecture that (i) supports the seconds-resolved, real-time measurement of specific molecular analytes over extended periods in freely moving, normally behaving rats and (ii) we believe is easily transferrable to other researchers. The approach also enables concurrent behavioral tracking captured ambulation metrics, which can reveal correlations between the in vivo concentrations of psychoactive drugs and locomotor behavior. The results of this multimodal approach validate EAB sensors for multianalyte detection in dynamic physiological contexts and highlights the physiological and psychobiological relevance of interstitial fluid drug concentrations, with implications for precision dosing, real-time molecular diagnostics, and behavioral pharmacology.
Abstract Translating molecular-scale chemical interactions into intuitive and information-rich visual representations remains a central challenge in chemical sensing. Liquid crystals (LCs) provide a stimulus-responsive optical medium for chemical-to-optical transduction; however, existing approaches primarily rely on predefined optical responses rather than programmable representations of multiple chemical concentrations. Here, we introduce a laser-projection-programmed LC platform that extends established LC visual sensing toward programmable, multilevel concentration-to-symbol encoding. By integrating near ultraviolet laser-written photoalignment with visible laser readout in a write–read decoupled projection architecture, the LC anchoring configuration and polarization response can be programmed directly through projected optical patterns. Chemically induced changes in LC phase retardation are thereby converted into spatially programmed, naked-eye-readable optical symbols. Using acetone vapor as a model analyte, multiple concentration regimes are programmably encoded into distinct visual symbols, enabling intuitive interpretation of chemical exposure through symbolic visual outputs.
Abstract With the increasing complexity of in vitro models for tissues, cancer, and other diseases, there is a need to develop robust biosensors capable of addressing these dynamic systems. Herein, we demonstrate the use of surface-enhanced Raman scattering (SERS)-based biosensors to monitor pH in 3D cellular models. We load breast cancer cells with pH-sensitive SERS nanotags comprising polymer-encapsulated gold nanostars functionalized with the pH-sensitive Raman reporter molecule 4-mercaptobenzoic acid, we then seed the labeled cells onto a 3D-printed hydrogel scaffold and expose the model to different stimuli: a chemotherapeutic drug, a cytotoxic surfactant, and plasmonic heating. In all cases, the SERS nanotags demonstrate pronounced responses toward an increase in pH occurring over either minutes or days (depending on the stimulus), which is associated to cell membrane damage as confirmed by cytotoxicity assays. Our sensors enable pH mapping in 3D with subcellular resolution, extending to millimeter-sized 3D regions. Machine-learning-based analysis of SERS spectra makes possible the detection of pH fluctuations following biological changes in these models. This work sets out a roadmap for applying pH-sensitive SERS nanotags in advanced 3D in vitro models or hybrid biomaterials, thereby opening new avenues for continuous monitoring of intercellular communication, proliferation, viability, and more.
Abstract Flexible wearable sensors are increasingly used for long-duration monitoring of body-state information, but they can degrade silently during operation while continuing to output physiologically plausible signals, making it difficult to determine whether an incoming measurement remains trustworthy. Here, we report a self-prognostic electronic skin platform that couples multimodal body-state sensing with autonomous sensor-health assessment. The device monolithically co-integrates piezoelectric and triboelectric transduction by origami folding into an ultrathin, six-channel wrist-mounted array (∼0.1 mm, <1 g), so that a single mechanoelectrical stream simultaneously encodes cardiovascular pulsation, wrist activity, and the device’s own degradation state. A two-stage self-diagnostic framework uses an autoencoder-CUSUM pipeline to establish device-specific failure labels from degradation trajectories, followed by an LSTM-Transformer model for remaining useful lifetime prediction. Across a twenty-device cohort with a nearly sevenfold variation in lifetime, the model predicts remaining useful lifetime across the cohort’s degradation trajectories with R2 = 0.95 and captures uncertainty that increases as degradation becomes more severe. In single-participant daily-use proof-of-concept testing, the system estimates physiological parameters and sensor remaining lifetime from the same stream. The predicted lifetime of a newly fabricated device remained near 100% during a representative 1.5 h segment and declined modestly to 97.2% over approximately 12 h of wear distributed across multiple days; this single-device demonstration illustrates the operation of the diagnostic channel during daily use rather than validated cross-device predictive accuracy. These results establish reliability-aware wearable sensing, in which each body-state measurement is interpreted together with the operational health of the sensor itself, with potential value for long-duration applications such as health monitoring and embodied intelligence.
Abstract Compact photoacoustic trace-gas sensors require acoustic detectors that combine high sensitivity with mechanical integrability, but conventional high-performance detectors are typically rigid, discrete components that are difficult to merge with shape-adaptive acoustic architectures. Here, we report a monolithic photoacoustic CO2 sensor enabled by an interface-engineered reconfigurable piezocomposite, in which the sensing film itself can serve as both the acoustic cavity wall and the piezoelectric detector. The water-processed composite combines Cu@PZT metal–ferroelectric heterointerfaces, sparse MWCNT electrical bridges and a glucose–urea-reconstructed cellulose matrix. Surface-anchored Cu domains on PZT act as localized charge-regulation sites that mitigate polymer dielectric shielding and depolarization effects, yielding a piezoelectric coefficient of 83.2 pC N–1, while the dynamic hydrogen-bonded cellulose network provides the deformability required for conformal and tubular architectures. In a planar PAS configuration, the piezocomposite functions as a flexible acoustic detector attached to a discrete resonant cavity, giving a CO2 sensitivity of 2.92 mV ppm–1 and a detection limit of 148 ppb. When rolled into a monolithic tubular sensor, the same film forms the resonant cavity wall and performs wall-active acoustic-to-electrical transduction, increasing the sensitivity to 7.11 mV ppm–1 and lowering the detection limit to 13 ppb at a 10 s integration time, with a normalized noise equivalent absorption of 2.03 × 10–8 cm–1 W Hz–1/2. This work establishes a material-to-sensor-architecture route for wall-active photoacoustic trace-gas detection, showing how reconfigurable piezocomposites can integrate acoustic resonance and electrical detection within a single deformable sensing structure.
