Towards antimicrobial yet bioactive Cu-alginate hydrogels

Abstract

The simplest approach to enhance alginate hydrogel characteristics and functional properties is to replace the calcium in the process of alginate gelation with other metallic ions which are essential for living systems. Gelling of alginate with other ions and using modern encapsulation techniques can provide new delivery systems with required properties. Hence, in this study Cu-alginate hydrogels in the form of microbeads were produced by electrostatic extrusion using gelling solutions with Cu(II) concentrations in the range 13.5-270 mM and comprehensively characterized in vitro. The variation of gelling solution concentration influenced the microbead Cu(II) content, size, biomechanical properties, Cu(II) release and subsequently potential biomedical application. The formulations chosen for biomedical evaluation showed potential for antimicrobial and tissue engineering applications. Microbeads with higher Cu(II) loading (~100 μmol g(-1)) induced immediate bactericidal effects against Escherichia coli and Staphylococcus aureus. Conversely, Cu(II) release from microbeads with the Cu(II) content of ~60 μmol g(-1) was slower and they were suitable for promoting and maintaining chondrogenic phenotype of bovine calf chondrocytes in 3D culture. Results of this study have shown possibilities for tuning Cu-alginate properties for potential biomedical applications such as antimicrobial wound dressings, tissue engineering scaffolds or articular cartilage implants.

Calcium alginate beads reinforced with synthetic oligomers, linear polyethylenimine and Cu(II): structural stability and potential applications

“…On the other hand, Cu(II) itself released from the beads and diffusing in agar can act as an antimicrobial agent. Microbeads of copper-alginate hydrogels induced immediate bactericidal effects against Escherichia coli and Staphylococcus aureus (Malagurski et al 2016). The bead made without Cu(II) did not inhibit bacterial growth, indicating that the amount of oligomers released from the bead was innocuous, consistent with the results of cytotoxicity assays.…”

Antibacterial Hydrogels

“…Cu–SA hydrogels prepared through electrostatic extrusion were bactericidally effective against E. coli and MRSA ( Figure 5 ). 49 Cu–SA hydrogels, with higher Cu(II) loading (≈100 × 10 −6 m ), were produced by electrostatic extrusion using gelling solutions with Cu(II). The Cu–SA hydrogels exhibited immediate bactericidal effects against S. aureus and E. coli .…”

“…ZEO/PVA hydrogel with 0.48 wt% and higher cobalt‐exchanged ZEO contents showed efficient antibacterial activities against G− bacteria (i.e., E. coli and S. aureus ). Cu–SA hydrogels prepared through electrostatic extrusion were bactericidally effective against E. coli and MRSA ( Figure ) . Cu–SA hydrogels, with higher Cu(II) loading (≈100 × 10 −6 m ), were produced by electrostatic extrusion using gelling solutions with Cu(II).…”

“…Study and potential biomedical application of Cu–SA. Reproduced with permission . Copyright 2016, IOP.…”

Polydopamine functionalized hydrogel beads as magnetically separable antibacterial materials

“…30 Madzovska-Malagurski et al synthesized bioactive Cualginate hydrogels and showed their bactericidal activity against Escherichia coli and Staphylococcus aureus. 31 Nevertheless, the long-term toxic effects induced by leached metal ions (silver and copper) questions their utility for water treatment.…”