Real time monitoring of wound healing is still a major challenge for clinical tissue regeneration. Biomaterial guided on-site monitoring of wound healing is needed. Recently, Shanghai Univer professor Gao Jie / Zhejiang Province People’s Hospital Dr. Zhang Lei / Fudan University Zhongshan Hospital Dr. Jiang Libo / Hubei University professor Li Yulin research team proposed a multi-functional double color integrated polyacrylamide quaternary ammonium salt carbon quantum dots (CQDs) – phenol red hydrogel, designed to simultaneously detect wound pH value, reduce bacterial infection, promote wound healing.
The hybridization of CQDs and pH indicator (Fen Hong) with hydrogels gives them an accurate indication of high responsiveness, reversibility and pH changes to reflect the dynamic wound state under ultraviolet and visible light. In addition, these visual images can be collected by smart phones and converted into on-site wound pH signals, so that the dynamic condition of the wound can be evaluated remotely and in real time. It is worth noting that hydrogel has excellent hemostatic and adhesive properties, maintains slobber moisture and promotes wound healing through its high antibacterial activity (targeting Staphylococcus aureus and Escherichia coli) and skin repair. In general, the resulting hydrogel has high potential as a new intelligent and flexible wound dressing platform for the treatment of skin regeneration. The related papers, entitled flexible bicolorimetric polycarylamide / chitosan hydrogels for smart real-time monitoring and promotion of sound heating, were published in advanced functional materials.
Fig. 1 pH sensitivity function of hydrogel. A) in the sunlight, the color of the hydrogel changes with the change of pH value. In addition, under ultraviolet radiation (365 nm excitation wavelength), the fluorescence of hydrogel decreased with the increase of pH value. B) the fluorescence intensity of hydrogel, fluorescent hydrogel and CQD solution at the same excitation wavelength were compared. C) the fluorescence emission spectra of hydrogels at different pH values. The linear relationship between fluorescence intensity and pH value of D PAM-QCS-C-P hydrogel under 365 nm radiation was obtained. E) the reversible potential of PAM-QCS-C-P hydrogel at 365 nm radiation at a pH value of 5-8.
Figure 2 real time pH monitoring function guided by smart phone. A) read and monitor pH values of hydrogels by mobile phone. B) RGB images of PAM-QCS-C-P hydrogel under different pH values under visible and ultraviolet irradiation. The R, G, B and fitting curves of hydrogel as pH value function under ultraviolet light in C and visible light and D were shown.
Fig. 3 mechanical strength and swelling properties of hydrogel (PAM, PAM-QCS, PAM-QCS-C, PAM-QCS-C-P hydrogel). A) Compressive stress-strain curve. B) cyclic compression loading unloading curves of PAM, PAM-QCS, PAM-QCS-C and PAM-QCS-C-P hydrogels. C) Tensile stress-strain curve. D) cyclic tensile loading unloading curves of PAM, PAM-QCS, PAM-QCS-C and PAM-QCS-C-P hydrogels. E) the storage modulus (G’) and loss modulus (G “) of each hydrogel. F) swelling rate of hydrogel.
Fig. 4 in vitro antibacterial activity of PAM-QCS-C-P hydrogel. A) the image of bacterial colony forming units after 24 hours of culture on hydrogel. B) the representative FESEM images of bacteria contacted with PAM and PAM-QCS-C-P hydrogels.
Fig. 5 hemostatic ability and biocompatibility of PAM-QCS-C-P hydrogel in vivo. A) the photo shows the potential of hydrogel in hemostasis of the liver. B) Liver blood loss rate. The two groups were compared with the students’ unpaired t-test. C) cytotoxicity of hydrogels. D) incubated with hydrogels for 24, 48 and 72 hours of representative fluorescence images.
The healing effect of hydrogel (PAM, PAM-QCS, PAM-QCS-C, PAM-QCS-C-P hydrogel) in vivo. A) The change of pH value of wound in mice. B) Wound repair rate. C) representative photographs of wounds on days zeroth, fourth, sixth, 10 and 14, and D) simulation analysis of skin healing in mice treated with different hydrogels. E) H & E and Masson trichrome staining of wound tissue. Blood vessels are highlighted by black circles; The hair follicles were highlighted with green arrows; Collagen fibers are highlighted by red circles.
The team developed a multifunctional PAM/ chitosan hydrogel with real-time monitoring, antibacterial and wound healing capabilities. Hybridization of hydrogels with CQD and pH indicator (Fen Hong) to obtain high response, reversible and accurate pH instructions, reflecting the wound state under ultraviolet and visible light, can be collected and converted to pH data by mobile phone, enabling real-time detection of wound healing process in a remote intelligent manner. More importantly, the hydrogel has excellent hemostatic, skin adhesion, moisturizing and antibacterial activities, and promotes wound healing in a synergistic way. The resulting hydrogel can be used as a wound dressing for the treatment of skin regeneration, completely changing wound care in hospitals, primary health care institutions and communities.