Rapid and on-site wireless immunoassay of respiratory virus aerosols via hydrogel-modulated resonators.

Rapid and accurate detection of respiratory virus aerosols is highlighted for virus surveillance and infection control. Here, we report a wireless immunoassay technology for fast (within 10 min), on-site (wireless and battery-free), and sensitive (limit of detection down to fg/L) detection of virus antigens in aerosols. The wireless immunoassay leverages the immuno-responsive hydrogel-modulated radio frequency resonant sensor to capture and amplify the recognition of virus antigen, and flexible readout network to transduce the immuno bindings into electrical signals. The wireless immunoassay achieves simultaneous detection of respiratory viruses such as severe acute respiratory syndrome coronavirus 2, influenza A H1N1 virus, and respiratory syncytial virus for community infection surveillance. Direct detection of unpretreated clinical samples further demonstrates high accuracy for diagnosis of respiratory virus infection. This work provides a sensitive and accurate immunoassay technology for on-site virus detection and disease diagnosis compatible with wearable integration.

Wireless, noninvasive therapeutic drug monitoring system for saliva measurement toward medication management of schizophrenia.

As an efficient patient management tool of precision medicine, decentralized therapeutic drug monitoring (TDM) provides new vision for therapy adherence and health management of schizophrenia in a convenient manner. To dispense with psychologically burdensome blood sampling and to achieve real-time, noninvasive, and continual circulating tracking of drugs with narrow therapeutic window, we study the temporal metabolism of clozapine, an antipsychotic with severe side effect, in rat saliva by a wireless, integrated and patient-friendly smart lollipop sensing system. Highly sensitive and efficient sensing performance with acceptable anti-biofouling property was realized based on the synergistic effect of electrodeposited reduced graphene oxide and ionic liquids in pretreatment-free saliva with low detection limit and good accuracy cross-validated with conventional method. On this basis, continual salivary drug levels with distinctive pharmacokinetics were found in different routes of drug administration. Pilot experiment reveals a strong correlation between blood and saliva clozapine and a positive relationship between drug dosage and salivary drug level, indicating potential applications presented by noninvasive saliva analysis towards patient-centered and personalized pharmacotherapy and adherence management via proposed smart lollipop system.

All-MXene-Printed RF Resonators as Wireless Plant Wearable Sensors for In Situ Ethylene Detection.

Printed flexible electronics have emerged as versatile functional components of wearable intelligent devices that bridge the digital information networks with biointerfaces. Recent endeavors in plant wearable sensors provide real-time and in situ insights to study phenotyping traits of crops, whereas monitoring of ethylene, the fundamental phytohormone, remains challenging due to the lack of flexible and scalable manufacturing of plant wearable ethylene sensors. Here the all-MXene-printed flexible radio frequency (RF) resonators are presented as plant wearable sensors for wireless ethylene detection. The facile formation of additive-free MXene ink enables rapid, scalable manufacturing of printed electronics, demonstrating decent printing resolution (2.5% variation), ≈30000 S m-1 conductivity and mechanical robustness. Incorporation of MXene-reduced palladium nanoparticles (MXene@PdNPs) facilitates 1.16% ethylene response at 1 ppm with 0.084 ppm limit of detection. The wireless sensor tags are attached on plant organ surfaces for in situ and continuously profiling of plant ethylene emission to inform the key transition of plant biochemistry, potentially extending the application of printed MXene electronics to enable real-time plant hormone monitoring for precision agriculture and food industrial management.

MXene-based wireless facemask enabled wearable breath acetone detection for lipid metabolic monitoring.

Breath acetone (BrAC) detection presents a promising scheme for noninvasive monitoring of metabolic health due to its close correlation to diets and exercise-regulated lipolysis. Herein, we report a Ti3C2Tx MXene-based wireless facemask for on-body BrAC detection and real-time tracking of lipid metabolism, where Ti3C2Tx MXene serves as a versatile nanoplatform for not only acetone detection but also breath interference filtration. The incorporation of in situ grown TiO2 and short peptides with Ti3C2Tx MXene further improves the acetone sensitivity and selectivity, while TiO2-MXene interfaces facilitate light-assisted response calibration. To further realize wearable breath monitoring, a miniaturized flexible detection tag has been integrated with a commercially available facemask, which enables facile BrAC detection and wireless data transmission. Through the hierarchically designed filtration-detection-calibration-transmission system, we realize BrAC detection down to 0.31 ppm (part per million) in breath. On-body breath tests validate the facemask in dynamically monitoring of lipid metabolism, which could guide dieter, athletes, and fitness enthusiasts to arrange diets and exercise activities. The proposed wearable platform opens up new possibility toward the practice of breath analysis as well as daily lipid metabolic management.

Elimination of oxygen interference in the photoelectrochemical sensor with ferricyanide shield oxygen reduction for point of care testing.

As a sensitive and promising detection method, photoelectrochemical (PEC) sensor has been widely used in biochemical analysis field. However, the interferences from environment, especially dissolved oxygen, often impact the stability and precision of PEC sensors, which limit its practical applications. Here, we report a dissolved oxygen insensitive PEC sensor based on a proposed indirect electron transfer model. Through the detailed study of the charge transfer process, we determined that the photocurrent mainly comes from the electrochemical reaction between the photochemical products and the electrode, rather than direct charge transfer between the photoelectric materials and the electrode. The newly designed PEC sensor used ferricyanide to shield oxygen reduction and eliminated the influence from variable oxygen solubility. This sensor maintained robust responses over an extremely wide range (1.0-7.5 mg/L) of dissolved oxygen concentrations. To further demonstrate its capability, a smartphone based portable immunosensor was constructed for the detection of human serum albumin (HSA), which exhibited excellent stability and accuracy. The relative error of current was reduced by 81.3% over traditional electron donor solution. This work effectively improves the stability of PEC sensors, and lays the foundation for the subsequently practical applications of PEC sensor in point-of-care testing.