Tailoring the Electron Trapping Effect of a Biocompatible Triboelectric Hydrogel by Graphene Oxide Incorporation towards Self-Powered Medical Electronics

Triboelectric nanogenerators (TENGs) are associated withseveraldrawbacks that limit their application in the biomedical field, includingtoxicity, thrombogenicity, and poor performance in the presence offluids. By proposing the use of a hemo/biocompatible hydrogel, poly-(2-hydroxyethylmethacrylate) (pHEMA), this study bypasses these barriers. In contact-separationmode, using polytetrafluoroethylene (PTFE) as a reference, pHEMA generatesan output of 100.0 V, under an open circuit, 4.7 mu A, and 0.68W/m(2) for an internal resistance of 10 M omega. Our findingsunveil that graphene oxide (GO) can be used to tune pHEMA'striboelectric properties in a concentration-dependent manner. At thelowest measured concentration (0.2% GO), the generated outputs increaseto 194.5 V, 5.3 mu A, and 1.28 W/m(2) due to the observedincrease in pHEMA's surface roughness, which expands the contactarea. Triboelectric performance starts to decrease as GO concentrationincreases, plateauing at 11% volumetric, where the output is 51 V,1.76 mu A, and 0.17 W/m(2) less than pHEMA's.Increases in internal resistance, from 14 omega M to greater than470 omega M, zeta-potential, from -7.3 to -0.4 mV,and open-circuit characteristic charge decay periods, from 90 to 120ms, are all observed in conjunction with this phenomenon, which pointsto GO function as an electron trapping site in pHEMA's matrix.All of the composites can charge a 10 mu F capacitor in 200 s,producing a voltage between 0.25 and 3.5 V and allowing the operationof at least 20 LEDs. The triboelectric output was largely steady throughoutthe 3.33 h durability test. Voltage decreases by 38% due to contact-separationfrequency, whereas current increases by 77%. In terms of pressure,it appears to have little effect on voltage but boosts current outputby 42%. Finally, pHEMA and pHEMA/GO extracts were cytocompatible towardfibroblasts. According to these results, pHEMA has a significant potentialto function as a biomaterial to create bio/hemocompatible TENGs andGO to precisely control its triboelectric outputs.

Automated summary

This study proposes the use of a hemo/biocompatible hydrogel material (poly-(2-hydroxyethyl methacrylate)) to overcome the limitations of triboelectric nanogenerators (TENGs) in the biomedical field. Graphene oxide (GO) is found to modulate the triboloelectric properties of the hydrogel in a concentration-dependent manner. The study also reveals the role of GO as an electron trapping site in the hydrogel matrix.