Wireless,multimodal sensors for continuous measurement of pressure,temperature,and hydration of patients in wheelchair

Individuals who are unable to walk independently spend most of the day in a wheelchair.This population is at high risk for developing pressure injuries caused by sitting.However,early diagnosis and prevention of these injuries still remain challenging.Herein,we introduce battery-free,wireless,multimodal sensors and a movable system for continuous measurement of pressure,temperature,and hydration at skin interfaces.The device design includes a crack-activated pressure sensor with nanoscale encapsulations for enhanced sensitivity,a temperature sensor for measuring skin temperature,and a galvanic skin response sensor for measuring skin hydration levels.The movable system enables power harvesting,and data communication to multiple wireless devices mounted at skin-cushion interfaces of wheelchair users over full body coverage.Experimental evaluations and numerical simulations of the devices,together with clinical trials for wheelchair patients,demonstrate the feasibility and stability of the sensor system for preventing pressure injuries caused by sitting.

Electronic Skin from High-Throughput Fabrication of Intrinsically Stretchable Lead Zirconate Titanate Elastomer

Electronic skin made of thin,soft,stretchable devices that can mimic the human skin and reconstruct the tactile sensation and perception offers great opportunities for prosthesis sensing,robotics controlling,and human-machine interfaces.Advanced materials and mechanics engineering of thin film devices has proven to be an efficient route to enable and enhance flexibility and stretchability of various electronic skins;however,the density of devices is still low owing to the limitation in existing fabrication techniques.Here,we report a high-throughput one-step process to fabricate large tactile sensing arrays with a sensor density of 25 sensors/cm^(2) for electronic skin,where the sensors are based on intrinsically stretchable piezoelectric lead zirconate titanate(PZT)elastomer.The PZT elastomer sensor arrays with great uniformity and passive-driven manner enable highresolution tactile sensing,simplify the data acquisition process,and lower the manufacturing cost.The high-throughput fabrication process provides a general platform for integrating intrinsically stretchable materials into large area,high device density soft electronics for the next-generation electronic skin.

Analytical Modeling of Flowrate and Its Maxima in Electrochemical Bioelectronics with Drug Delivery Capabilities

Flowrate control in flexible bioelectronics with targeted drug delivery capabilities is essential to ensure timely and safe delivery.For neuroscience and pharmacogenetics studies in small animals,these flexible bioelectronic systems can be tailored to deliver small drug volumes on a controlled fashion without damaging surrounding tissues from stresses induced by excessively high flowrates.The drug delivery process is realized by an electrochemical reaction that pressurizes the internal bioelectronic chambers to deform a flexible polymer membrane that pumps the drug through a network of microchannels implanted in the small animal.The flowrate temporal profile and global maximum are governed and can be modeled by the ideal gas law.Here,we obtain an analytical solution that groups the relevant mechanical,fluidic,environmental,and electrochemical terms involved in the drug delivery process into a set of three nondimensional parameters.The unique combinations of these three nondimensional parameters(related to the initial pressure,initial gas volume,and microfluidic resistance)can be used to model the flowrate and scale up the flexible bioelectronic design for experiments in medium and large animal models.The analytical solution is divided into(1)a fast variable that controls the maximum flowrate and(2)a slow variable that models the temporal profile.Together,the two variables detail the complete drug delivery process and control using the three nondimensional parameters.Comparison of the analytical model with alternative numerical models shows excellent agreement and validates the analytic modeling approach.These findings serve as a theoretical framework to design and optimize future flexible bioelectronic systems used in biomedical research,or related medical fields,and analytically control the flowrate and its global maximum for successful drug delivery.

Flexible electronics with dynamic interfaces for biomedical monitoring,stimulation,and characterization

Recent developments in the fields of materials science and engineering technology(mechanical,electrical,biomedical)lay the foundation to design flexible bioelec-tronics with dynamic interfaces,widely used in biomedical/clinical monitoring,stimulation,and characterization.Examples of this technology include body motion and physiological signal monitoring through soft wearable devices,mechanical characterization of biological tissues,skin stimulation using dynamic actuators,and energy harvesting in biomedical implants.Typically,these bioelectronic systems feature thin form factors for enhanced flexibility and soft elastomeric encapsula-tions that provide skin‐compliant mechanics for seamless integration with biological tissues.This review examines the rapid and continuous progress of bioelectronics in the context of design strategies including materials,mechanics,and structure to achieve high performance dynamic interfaces in biomedicine.It concludes with a concise summary and insights into the ongoing opportunities and challenges facing developments of bioelectronics with dynamic interfaces for future applications.