On-Demand Changeable Theranostic Hydrogels and Visual Imaging-Guided Antibacterial Photodynamic Therapy to Promote Wound Healing

Abstract

Antibacterial wound dressings are confronted with the challenges in real-time imaging of infected wounds and effective removal of bacterial debris after sterilization to promote the healing process. Herein, injectable theranostic hydrogels were constructed from antimicrobial peptide ε-polylysine (ePL) and polydopamine (PDA) nanoparticles for real-time diagnosis of infected wounds, imaging-guided antibacterial photodynamic therapy (PDT), and on-demand removal of bacterial debris. Ureido-pyrimidinone was conjugated on ePL to produce PLU hydrogels through quadruple hydrogen bonding, and the inoculation of tetrakis(4-carboxyphenyl)porphyrin (TCPP)-loaded PDA (PTc) nanoparticles introduced Schiff base linkages in PLU@PTc hydrogels. The double-cross-linked networks enhance mechanical performance, adhesion strength, and self-healing properties of hydrogels, and the dynamic cross-linking enables their photothermal removal. The injection of PLU precursors and PTc NPs generates in situ sol−gel transformation, and the acid-triggered release of TCPP restores fluorescence emissions for real-time imaging of infected wounds under 410 nm illumination. Then, the released TCPP in the infected wounds is illuminated at 660 nm to launch a precise antibacterial PDT, which is strengthened by the bacterial capture on hydrogels. Hydrogels with wrapped bacterial debris are removed under illumination at 808 nm, and the hydrogel dressing change accelerates healing of infected wounds through simultaneous relief of oxidative stress, regulation of inflammatory factors, acceleration of collagen deposition, and promotion of angiogenesis. Thus, this study demonstrates a feasible strategy for wound infection theranostics through bacterial infection-triggered visual imaging, efficient nonantibiotic sterilization, and on-demand dressing change and bacterial debris removal.

Fabrication and Facile Surface Derivatization of Poly(ε‐caprolactone)‐Based Wound Dressing Materials Imparting Anti‐Infective, Excessive Biofluid Drainage, and Easy‐to‐Peel Characteristics

“…Therefore, to support the healing process, an efficient wound-dressing material requires to fulfil the criteria of antimicrobial maintenance, preserving optimal humidity across the site with proper drainage of excessive biofluid, porosity, nonantigenic, noncytotoxic, antioxidant, anti-inflammatory, and nonadhesive for easy removal. [11][12][13][14][15][16][17] These aspects highlight the immense need for a therapeutic dressing material possessing multifaceted properties. [18][19][20] A plethora of literature is available on wound-care materials based on the intended application, such as antimicrobial, debridement, absorbent, or occlusive.…”

Synergistic photothermal antibacterial therapy enabled by multifunctional nanomaterials: progress and perspectives

“…Ran et al designed and synthesized an injectable hydrogel for real-time bacterial detection, efficient bacterial capture and disinfection, and on-demand removal of bacterial fragments to promote the healing of infected wounds. 59 PDA nanoparticles have attracted more and more attention because of their biocompatibility and biodegradability, while ε-polysine (ePL) is a typical antibacterial peptide with rich l -lysine residues, which produces a broad spectrum of antibacterial activity by destroying bacterial walls. ePLU was obtained as a supramolecular self-assembly group by bonding hexamethylene diisocyanate (HDI) on ePL, and the obtained ePLU hydrogel crosslinked through a well-defined quadruple hydrogen bond.…”

Photodynamic and photothermal therapies for bacterial infection treatment

“…Recently, Li et al. overcame this weakness and devised a PLU@PTc hydrogel, which enables diagnosis, primary treatment, and secondary treatment [23] . In this reported work, a hybrid hydrogel consisting of polydipamine (PDA) nanoparticles and ε‐polylysine (ePL), which is a typical antibiomicrobial peptide, was synthesized.…”