Mendoza-Cerezo Laura, Rodríguez-Rego Jesús M, Macias-García A, Iñesta-Vaquera Francisco de Asís, Marcos-Romero Alfonso C
Departamento de Expresión Gráfica, Escuela de Ingenierías Industriales, Universidad de Extremadura, Avenida de Elvas, s/n, 06006 Badajoz, Spain.
Departamento de Bioquímica y Biología Molecular y Genética, Facultad de Ciencias, Universidad de Extremadura, Avenida de Elvas, s/n, 06006 Badajoz, Spain.
Gels. 2025 May 26;11(6):389. doi: 10.3390/gels11060389.
The development of printable, conductive, and biocompatible hydrogels has emerged as a promising strategy for the next generation of flexible and soft sensor platforms. In this study, we present a systematic investigation of alginate-based hydrogels incorporating different carbonaceous materials, natural graphite, carbon black (Vulcan V3), and activated carbon (PCO1000C), to evaluate their suitability for sensor applications. Hydrogels were formulated with varying concentrations of sodium alginate and a fixed loading of carbon additives. Each composite was characterized in terms of electrical conductivity under compression, rheological behavior, and mechanical strength. Printability was assessed using a custom-designed extrusion platform that allowed for the precise determination of the minimum force and optimal conditions required to extrude each formulation through a standard 20G nozzle. Among all tested systems, the alginate-graphite hydrogel demonstrated superior extrudability, shear-thinning behavior, and shape fidelity, making it well-suited for 3D printing or direct ink writing. A simple conductivity-testing device was developed to verify the electrical response of each hydrogel in the hydrated state. The effects of different drying methods on the final conductivity were also analyzed, showing that oven drying at 50 °C yielded the highest restoration of conductive pathways. Mechanical tests on printed structures confirmed their ability to maintain shape and resist compressive forces. Finally, the biocompatibility of the printed alginate-graphite hydrogel was validated using a standard cytotoxicity assay. The results demonstrated high cell viability, confirming the material's potential for use in biomedical sensing environments. This work offers a robust framework for the development of sustainable, printable, and biocompatible conductive hydrogels. The combined performance in printability, mechanical integrity, electrical conductivity, and cytocompatibility highlights their promise for flexible biosensors and wearable sensor technologies.
可打印、导电且生物相容的水凝胶的开发已成为下一代柔性和软传感器平台的一种有前景的策略。在本研究中，我们对包含不同碳质材料（天然石墨、炭黑（Vulcan V3）和活性炭（PCO1000C））的藻酸盐基水凝胶进行了系统研究，以评估它们在传感器应用中的适用性。用不同浓度的海藻酸钠和固定负载量的碳添加剂配制水凝胶。对每种复合材料在压缩状态下的电导率、流变行为和机械强度进行了表征。使用定制设计的挤出平台评估可打印性，该平台允许精确确定通过标准20G喷嘴挤出每种配方所需的最小力和最佳条件。在所有测试系统中，藻酸盐 - 石墨水凝胶表现出优异的可挤出性、剪切变稀行为和形状保真度，使其非常适合3D打印或直接墨水书写。开发了一种简单的电导率测试装置来验证每种水凝胶在水合状态下的电响应。还分析了不同干燥方法对最终电导率的影响，结果表明在50°C下烘箱干燥能使导电路径恢复程度最高。对打印结构的力学测试证实了它们保持形状和抵抗压缩力的能力。最后，使用标准细胞毒性试验验证了打印的藻酸盐 - 石墨水凝胶的生物相容性。结果表明细胞活力高，证实了该材料在生物医学传感环境中的应用潜力。这项工作为可持续、可打印且生物相容的导电水凝胶的开发提供了一个强大的框架。在可打印性、机械完整性、电导率和细胞相容性方面的综合性能突出了它们在柔性生物传感器和可穿戴传感器技术中的前景。
