Near-IR-Regulated Composite Hydrogel with Real-Time Infection Monitoring and a Combined Antibacterial Effect for Efficient Wound Management

Abstract

Chronic wounds induced by bacterial infection have seriously affected the health of people in the world. So, it is meaningful to develop a novel strategy with real-time infection monitoring and excellent antibacterial performance for enhancing wound management. Herein, we constructed a composite hydrogel by loading the pH indicator bromothymol blue (BTB) and gold nanocages containing 2,2′-azobis[2-(2-imidazolin-2-yl)propane] dihydrochloride (Au NCs@AIPH) into a polyacrylamide-co-poly(acrylic anhydride-modified oxidized sodium alginate) (PAM-co-PAOSA) hydrogel. In vitro and in vivo experimental results demonstrated that the composite hydrogel could effectively detect bacteria and diagnose the infection status of a wound in real time by showing visible color changes. In addition, the composite hydrogel containing Au NCs@AIPH possessed an excellent photothermal effect under near-IR (NIR) laser irradiation. The photothermal effect further activated AIPH to generate toxic free radicals to form combined antibacterial therapy for accelerating wound healing. Moreover, the composite hydrogel showed great biocompatibility. Therefore, the multifunctional hydrogel provided a novel wound management strategy for bacterial infection diagnosis and combined therapy in an infected wound.

Hydrogel-based dressings designed to facilitate wound healing

“…Consequently, researchers have proposed the development of multifunctional hydrogel-based dressings to enable comprehensive monitoring of various parameters in wound healing, including pH levels, pressure, infection status, temperature, and glucose levels. 303–307 A novel method has been developed for the in situ biosynthesis of functional conjugated polymers within artificial hydrogels, utilizing the biological microenvironment. This approach allowed for the real-time monitoring of wound infection and the inhibition of bacteria.…”

Nanomaterials for Photothermal Antimicrobial Surfaces

“…Other promising shapes, with the same characteristics in terms of red-shift of the LSPR band, are cages and rods. Au nanocages (AuNCs) prepared by the galvanic replacement method were embedded in polyacrylamide- co -poly(acrylic anhydride-modified oxidized sodium alginate) (PAM- co -PAOSA) hydrogel, as shown in a paper from Chen et al 69 These films possess an absorption band at 800 nm that results in a local increase in temperature when irradiated, yielding a strong photothermal antibacterial effect against E. coli and S. aureus after irradiation. The last AuNP shape worth mentioning is gold nanorods (GNRs), which are widely used in the photothermal antibacterial field due to the two LSPR bands present in the UV–vis–NIR spectrum: one weak transverse band in the visible region and a second, more intense, longitudinal band centered in the NIR ( Figure 1 D.1).…”

Color changing bioadhesive barrier for peripherally inserted central catheters

“…Bromothymol blue (BTB) is a known candidate for bacterial detection. 30–32 (2) Photocured CathoGlu reduces bacteria permeability by one order of magnitude or more. Finally, a non-inferiority pre-clinical in vivo study (porcine model) compares CathoGlu to clinically approved adhesive formulation and tape.…”