Orange-Emissive Carbon Quantum Dots: Toward Application in Wound pH Monitoring Based on Colorimetric and Fluorescent Changing

Monitoring of wound pH is critical for interpreting wound status, because early identification of wound infection or nonhealing wounds is conducive to administion of therapies at the right time. Here, novel orange-emissive carbon quantum dots (O-CDs) are synthesized via microwave-assisted heating of 1,2,4-triaminobenzene and urea aqueous solution. The as-prepared O-CDs exhibit distinctive colorimetric response to pH changing, and also display pH-sensitive fluorescence. Benefiting from the response of O-CDs over a wound-relevant pH range (5-9), medical cotton cloth is selected to immobilize O-CDs through hydrogen bond interactions, the resultant O-CDs-coated cloth with emission at 560 nm shows a high response to pH variation in the range of 5-9 via both fluorescence and visible colorimetric changes. Moreover, the sensitivity of fluorescence to pH is capable of establishing an analytical mode for determining pH value. Further, the O-CDs-based pH indicator possesses not only superior biocompatibility and drug compatibility but also excellent resistance leachability and high reversibility. Importantly, the usage of O-CDs-coated cloth to detect pH is free from the interference of blood contamination and long-term storage, thus providing a valuable strategy for wound pH monitoring through visual response and quantitative determination.