Figure 8

Flexible and stretchable physical sensing platforms for thermal therapy and drug delivery. (a) Stretchable and conformal mesh heating element for articular thermotherapy application. (i) Schematic illustration showing the fabrication process of the stretchable mesh heater, which comprised a heating layer of LE Ag NW/SBS elastomer composite and two encapsulation layers of SBS elastomers pressed together at high temperature. The colorized SEM image on the right shows the good interface between the three bonded mesh layers of SBS, LE Ag NW/SBS, and SBS. Scale bar, 50 μm. (ii) Optical image showing the large-area stretchable mesh heater (left). Optical image showing a wearable and portable heating system that integrated the stretchable mesh heater and a custom-made electronic band and the application of the integrated heating system on a wrist (center). Infrared camera images showing uniform heat distribution on the wrist (right). Adapted with permission from Ref. 48. Copyright 2015 American Chemical Society. (b) Soft elastic electronic dura mater or e-dura neural implants. (i) Optical image illustrating the fabricated e-dura implant and the accompanying SEM images of the stretchable gold interconnects and platinum–silicone composite-coated soft electrodes. (ii) Implantation of the e-dura between the motor cortex tissues and the dura mater for 6 weeks (left) and the reconstructed spinal cord activation map in response to electrical stimulation of the left sciatic nerve based on the recorded electrospinograms (right). (iii) Spinal cord injured rats with implanted spinal e-dura over the lumbosacral sections. (iv) Recording of the bipedal locomotion of the rat under support after 3 weeks of rehabilitation in the absence and presence of electrochemical stimulation and corresponding stick diagram decompositions of the hindlimb movements and oscillations and the leg muscle activities. Adapted with permission from Ref. 49. Copyright 2015 American Association for the Advancement of Science. (c) Wearable tensile strain-triggered drug delivery system. (i) Schematic illustration showing the two distinct components and the working mechanism of a strain-triggered drug delivery system in which deformation of the stretchable elastomer promoted drug release from the microdepot. (ii) Schematic illustration showing the encapsulation of the drug-loaded nanoparticles within the microdepot and the passive release and partial retention of the drug-filled nanoparticles within the microdepot matrices. (iii) Conformal attachment of the wearable drug delivery system onto the index finger where drug release to the skin could be simply triggered by the finger flexion. (iv) Integration of the wearable strain-responsive drug delivery system with a microneedle array patch for the transcutaneous administration of drugs. Adapted with permission from Ref. 50. Copyright 2015 American Chemical Society.