Self-reconfigurable high-weight-per-volume-gelatin films for all-solution-processed on-skin electronics with ultra-conformal contact

• Published in: Biosensors & bioelectronics Vol. 184; p. 113231
• Main Authors: Choi, Hyeong-Jun, Kang, Byeong-Cheol, Ha, Tae-Jun
• Format: Journal Article
• Language: English
• Published: England Elsevier B.V 15.07.2021
• Subjects: Biosensing Techniques; Electronics; Gelatin; High-weight-per- volume-gelatin; Humans; On-skin electronics; Prospective Studies; Reproducibility of Results; Self-reconfiguration; Silver nanowires; Ultra-conformal contact; Wearable Electronic Devices; On-skin electronics; Ultra-conformal contact; Self-reconfiguration; High-weight-per- volume-gelatin; Silver nanowires
• ISSN: 0956-5663; 1873-4235
• DOI: 10.1016/j.bios.2021.113231

Although conventional skin-attachable electronics exhibit good functionalities, their direct attachment (without any adhesive) to human skin with sufficient conformal contact is challenging. Herein, all-solution-processed on-skin electronics based on self-reconfigurable high-weight-per- volume-gelatin (HWVG) film constructed using an effective, biocompatible water absorption-evaporation technique are demonstrated. Completely conformal contact of self-reconfigurable HWVG films is realized by rapidly inducing anisotropic swelling in the perpendicular direction and covering any curvature on the skin without spatial gap or void after shrinking. A sufficiently thin HWVG film (~2 um) exhibited higher adhesion owing to van der Waals force and the carboxylic acid and amine groups in HWVG film form cross-linkages through intermolecular bonds with human skin. Self-reconfigurable HWVG films with high biocompatibility are optimized to afford a superior efficiency of 87.83 % at a concentration of 20 % (w/v) and a storage modulus of 1822 MPa at 36.5 °C. Furthermore, functional nanoelectrodes consisting of self-reconfigurable silver nanowires/HWVG films for high-performance on-skin sensors allowing the detection of sensitive motion and electrophysiological signals, as well as an armband-type sensor system incorporated with a smartphone for health-care monitoring are demonstrated. Outstanding performances, including stability, reliability, flexibility, re-usability, biocompatibility, and permeability of on-skin electronics based on HWVG films can open-up a prospective route to realizing breathable human-machine interfaces based on biocompatible materials and processes. •Effective and biocompatible self-reconfiguration is investigated for ultra-conformal contact of AgNWs/HWVG film.•All-solution-processed on-skin electronics and sensor system incorporated with a smartphone are demonstrated.•Outstanding stability, reliability, flexibility, re-usability, and biocompatibility of on-skin electronics are achieved.