PDA/Cu Bioactive Hydrogel with “Hot Ions Effect” for Inhibition of Drug-Resistant Bacteria and Enhancement of Infectious Skin Wound Healing

Abstract

Quick and effective sterilization of drug-resistant bacteria inevitably became an ever-growing global challenge. In this study, a multifunctional composite (PDA/Cu-CS) hydrogel mainly composed of polydopamine (PDA) and copper-doped calcium silicate ceramic (Cu-CS) was prepared. It was confirmed that PDA/copper (PDA/Cu) complexing in the composite hydrogel played a key role in enhancing the photothermal performance and antibacterial activity. Through a unique “hot ions effect”, created by the heating of Cu ions through the photothermal effect of the composite hydrogel, the hydrogel showed high-efficiency, quick, and long-term inhibition of methicillin-resistant Staphylococcus aureus and Escherichia coli. In addition, the hydrogel possessed remarkable bioactivity to stimulate angiogenesis. The in vivo results confirmed that the “hot ions effect” of the composite hydrogel removed existing infection in the wound area efficiently and significantly promoted angiogenesis and collagen deposition during infectious skin wound healing. Our results suggested that the design of multifunctional hydrogels with “hot ions effect” may be an effective therapeutic approach for the treatment of infectious wounds.

A Review on Hydrogels with Photothermal Effect in Wound Healing and Bone Tissue Engineering

“…DA can be grafted onto polymer materials, such as GelMA [ 81 ], hyaluronic acid(HA) [ 82 ], and bioactive glass nanoparticles (BGNs) [ 83 ], to improve its adhesion ability. In addition, DA could chelate with other photothermal materials (such as Cu 2+ [ 84 ], and Ti [ 85 ]) to increase the photothermal performance of hydrogels. Furthermore, the catechol group can be easily oxidized to the catechol–quinone group, which further forms chemical cross-links to improve the mechanical properties of hydrogels [ 86 , 87 ].…”

“…In the first cycle, the antibacterial activity of a PDA/Cu hydrogel against E. coli reached 88.37%, whereas the Cu group showed poor antibacterial activity (9.30%). After the second NIR irradiation cycle of 2 h, the antibacterial rate of the PDA/Cu hydrogel was 98.53%, whereas the antibacterial rate of the hydrogel without NIR irradiation was 79.48% [ 84 ]. Moreover, the CuS/MoS 2 /PVA hydrogel could produce hyperthermia and reactive oxygen species under NIR/visual light to provide an antibacterial treatment.…”

“…Moreover, by simulating the “hot spring effect”, mild heat can be incorporated with Fe 2+ , SiO 4 4− ions to regulate the expression of vascular genes such as hypoxia inducible factor-1 (HIF-1α), vascular endothelial growth factor (VEGF), endothelial nitric oxide synthase (eNOs), basic fibroblast growth factor (bFGF), and further promote circulation of blood ( Figure 3 ) [ 112 ]. Moreover, Cu 2+ and Mo 4+ ions could promote angiogenesis by promoting the expression of related genes (VEGF, KDR, HIF-α, eNOs, bFGF) [ 68 , 84 ]. HIF-α can mimic hypoxia environment to induce cell differentiation.…”

Recent Advances in a Polydopamine-Mediated Antimicrobial Adhesion System

“…Stronger NIR absorption has been attributed to the presence of PDA polymer and Cu-CaSil powder, two hydrogel components, both possessing photothermal property, and the right PDA/Cu ratio leads to a number of tetracoordinated structures in PDA-Cu complex responsible for enhancing absorption intensity. Since heat treatments are known to kill bacteria, the photothermal effect of the composite hydrogel PDA/Cu-CaSil with synergistic antibacterial function of Cu 2+ ions created unique "hot ions effect" by heating Cu 2+ ions through laser irradiation (Xu et al, 2020). Further, Cu/Ag/PDA/PET fabrics have been shown to possess good antibacterial property against E. coli (∼99%) due to the adhesive ability of PDA and its strong binding to Cu NPs.…”

Intelligent Silk Fibroin Based Microneedle Dressing (i‐SMD)

“…Several indexes of wound secretion, such as pH and inflammatory factors, are closely related to the wound recovery condition. [6][7][8][9][10] Therefore, monitoring these indexes could reflect the healing process. Currently, considerable effort has been devoted to devices to monitor wound detection and promote healing, such as hydrogel patches and microchips.…”