Microfluidic preparation and antibacterial properties of polyvinyl alcohol hydrogel microfibers loaded with MOF microparticles†

Antimicrobial polyvinyl alcohol (PVA) hydrogel microfibers that contain metal–organic framework microparticles with Ag⁺ (AMOF) and Zn²⁺ (ZMOF) and cellulose nanocrystals (CNCs) are controllably and continuously prepared by a microfluidic spinning method. The CNC endows the PVA networks with good mechanical properties via the formation of hydrogen bonds, while the AMOF and ZMOF allow the release of Ag⁺ and Zn²⁺ respectively for achieving antibacterial and antioxidant properties. The microfiber size can be flexibly and precisely regulated by adjusting the flow rates of both dispersed and continuous phases. The PVA hydrogel microfibers with both AMOF and ZMOF show tensile strengths of 4.78 MPa, and good stretchability of 768.3%. These microfibers show long-lasting ion release behaviors, with the released concentrations of Ag⁺ and Zn²⁺ ions reaching 1.113 mg L⁻¹ and 0.005 mg L⁻¹ within 96 h. Meanwhile, these microfibers exhibit good antimicrobial properties against E. coli O157:H7 and S. aureus within 24 h due to the Ag⁺ released from the AMOF. Moreover, such microfibers show good antioxidant properties by continuously inhibiting ·OH generation over 12 h due to the Zn²⁺ released from the ZMOF. This work provides a novel strategy for rational design and creation of hydrogel microfiber materials with good antimicrobial performances.