Design and Fabrication of Bilayer Hydrogel System with Self-Healing and Detachment Properties Achieved by Near-Infrared Irradiation

Abstract

Abstract:A novel kind of graphene oxide (GO)-containing bilayer hydrogel system with excellent self-healing and detachment properties stimulated by near-infrared irradiation is successively fabricated via a two-step in situ free radical polymerization. In addition to high mechanical strength, as components of a bilayer hydrogel system, a poly N,N-dimethylacrylamide (PDMAA) layer with 3 mg/mL GO and a poly N-isopropylacrylamide (PNIPAm) layer with 3 mg/mL GO exhibits firm interface bonding. GO in a PDMAA layer transforms under a near-infrared laser into heat, which promotes mutual diffusion of hydrogen bonds and realizes a self-healing property. The irradiation of near infrared laser results in the temperature of PNIPAm layer being higher than the volume phase transition temperature, reducing the corresponding biological viscidity and achieving detachment property. The increase of GO content enhances the self-healing degree and detachment rate. The bilayer hydrogel system fabricated via mold design combines characteristics of PDMAA layer and PNIPAm layer, which can be treated as materials for medical dressings, soft actuators, and robots.

Recent Achievements of Self-Healing Graphene/Polymer Composites

“…GO acted not only as a collaborative cross-linking agent, but also as a NIR irradiation energy absorber to transform it to thermal energy rapidly and efficiently to promote the mutual diffusion of the polymer chains across the cut interface. Liang and coworkers reported a self-healing bilayer hydrogel system [86]. When the fracture surfaces of the cut hydrogel were contacted, the healing is achieved by irradiating with a NIR illuminant with a wavelength of 808 nm and a power of 1.25 W. The self-healing behavior was ascribed to the photothermal energy transformation property of GO.…”

Photoresponsive hydrogel-based soft robot: A review

“…(2017)[ 55 ] PNIPAM/GO-PNIPAM halogen tungsten lamp(with a filter having cut off<600 ​nm) Bending 60s Software gripper Zhao et al. (2017)[ 51 ] GO-PDMAA/PNIPAM 808 ​nm NIR/(1.25 ​W/cm2) Bend off 105s Actuator Ma et al. (2018)[ 56 ] GO-PNIPAM/PBI-HPEI 532 ​nm Green light Bending(2D/3D) – Actuator Gao et al.…”

“…Due to the high photothermal conversion efficiency of GO, the GO-PNIPAM NC layer's hydrogel warmed at a faster rate than the other layer, resulting in bending. In addition, increasing the GO concentration (strength is greatest at 3 ​mg/ml) can increase the number of hydrogen bonds in the PDMAA layer, thereby enhancing the hydrogel's mechanical strength and self-healing properties [ 51 ]. By combining magnetic nanoparticles with the photothermal effect, Yoon et al.…”

Vancomycin-loaded hydrogels with thermal-responsive, self-peeling, and sustainable antibacterial properties for wound dressing

“…For example, Zhao et al combined graphene oxide (GO) and PNIPAAm to prepare thermal-responsive hydrogels for wound dressings. 16 Due to the photothermal effect of GO, the temperature of the hydrogel was increased under near-infrared light irradiation, and the adhesion of hydrogels was reduced to achieve self-peeling performance. Han et al fabricated a PNIPAAm/keratin double network gel that possessed thermo-sensitiveness imparting the self-stripping property.…”