Key Laboratory of Water and Sediment Sciences of Ministry of Education / State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing, 100875, China.
Shenzhen Engineering Research Laboratory for Sludge and Food Waste Treatment and Resource Recovery, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen, 518055, China; Environmental Engineering Research Centre, Department of Civil Engineering, The University of Hong Kong, Pokfulam, Hong Kong, China.
Environ Res. 2024 Dec 1;262(Pt 1):119856. doi: 10.1016/j.envres.2024.119856. Epub 2024 Aug 27.
Artificial biomanufacturing has been developed as a promising biotechnology for water pollution control. Effective bioimmobilization techniques are limited in application because of low productivity and the difficulty in achieving both mechanical strength and biocompatibility. Bioprinting technology, using biomaterials as bioink to enable the rapid on-demand production of bioactive structures, opens a new path for bioimmobilization. In this study, mimicking extracellular polysaccharide and protein of aerobic granular sludge (AGS), sodium alginate (SA) and silk fibroin methacryloyl (SilMA) were developed as the dual-component bioink with a suitable viscosity for bioprinting hydrogel. Interpenetrating network (IPN) hydrogel beads were manufactured using 1.5% (w/v) SA combined with 20% (w/v) SilMA through physical and covalent crosslinking, which exhibited excellent structural stability and bioactivity. The addition of SilMA provided a solution to the poor mechanical stability of SA-Ca hydrogels limited by Ca-Na ionic exchange. The unique structure of SilMA contributed to the reduction of hydrogel swelling as well as the prevention of SA loss. IPN hydrogels showed a swelling rate of less than 20% compared to the high swelling rate of more than 60% for SA hydrogels. On the other hand, SA controlled the hardening induced by excessive self-assembly of SilMA and improved mass transport in SilMA hydrogels. Compared to IPN hydrogels, SilMA hydrogels experienced a 15% volumetric shrinkage and exhibited a low water content of 92%. Sonication pretreatment of the dual-component bioink not only increased the intermolecular chain entanglement to form IPN, but also led to β-sheet content in SiMA reaching 46%-48%, which resulted in the formation of stable IPN hydrogels dominated entirely by physical crosslinking. Satisfactory proliferation and viability were achieved for the encapsulated bacteria in IPN hydrogels (μ 1.49-2.18 d). Further, the IPN biohydrogels could maintain structural stability as well as achieve pollutant removal for treating synthetic wastewater with high Na concentration of 300 mg/L. The novel SA/SilMA hydrogel bioprinting strategy established in this study offers a new direction for bioimmobilization in water pollution control and other environmental applications.
人工生物制造已被开发为一种有前途的水污染控制生物技术。有效的生物固定技术在应用中受到限制，因为它们的生产力低，并且难以同时实现机械强度和生物相容性。生物打印技术使用生物材料作为生物墨水，能够快速按需生产生物活性结构，为生物固定开辟了新途径。在这项研究中，模拟好氧颗粒污泥（AGS）的细胞外多糖和蛋白质，开发了海藻酸钠（SA）和丝素甲酰基（SilMA）作为双组分生物墨水，其粘度适合生物打印水凝胶。通过物理和共价交联，使用 1.5%（w/v）SA 与 20%（w/v）SilMA 制造互穿网络（IPN）水凝胶珠，表现出优异的结构稳定性和生物活性。SilMA 的加入解决了由 Ca-Na 离子交换限制的 SA-Ca 水凝胶机械稳定性差的问题。SilMA 的独特结构有助于减少水凝胶的溶胀并防止 SA 损失。与 SA 水凝胶的高溶胀率（超过 60%）相比，IPN 水凝胶的溶胀率小于 20%。另一方面，SA 控制了 SilMA 过度自组装引起的硬化，并改善了 SilMA 水凝胶中的传质。与 IPN 水凝胶相比，SilMA 水凝胶经历了 15%的体积收缩，水含量低至 92%。双组分生物墨水的超声预处理不仅增加了分子间链缠结以形成 IPN，而且导致 SiMA 中的β-折叠含量达到 46%-48%，从而形成完全由物理交联主导的稳定 IPN 水凝胶。封装在 IPN 水凝胶中的细菌增殖和活力令人满意（μ 1.49-2.18 d）。此外，IPN 生物水凝胶能够保持结构稳定性，并实现去除高 Na 浓度（300 mg/L）的合成废水中的污染物。本研究中建立的新型 SA/SilMA 水凝胶生物打印策略为水污染控制和其他环境应用中的生物固定提供了新方向。
