Colour-Changing Hydrogels with Smartphone Assistance for Wound Monitoring and Bacterial Detection

Background Particularly in individuals with diabetes, vascular diseases, and weakened immune systems, wound infection continues to be one of the main causes of delayed healing and chronic wound development. Although they offer physical protection, conventional wound dressings are unable to continuously assess the condition of the wound or identify infection early on. Recent developments in biomaterials have resulted in the creation of intelligent, stimuli-responsive hydrogels that can combine medicinal administration, infection detection, and wound monitoring into a single multipurpose platform. Objective With a focus on smartphone-assisted RGB colour analysis for quantitative point-of-care diagnostics, this study highlights current advancements in colour-changing smart hydrogels for wound monitoring and bacterial infection detection. Methods A thorough review of the literature on infection-responsive hydrogels was conducted, with particular attention to polymeric materials, fabrication techniques, colourimetric sensing systems, theranostic applications, pH-, enzyme-, and bacteria-responsive mechanisms, and digital wound monitoring technologies. To provide real-time visual monitoring of wound condition, the review also addresses the integration of synthetic pH-sensitive dyes, natural pigments, and nanomaterial-based optical sensors into hydrogel matrices. Results Through reversible colour changes and regulated therapeutic release, smart hydrogels react dynamically to infection-associated indicators such as pH variations, reactive oxygen species, bacterial enzymes, and microbial metabolites. Anthocyanins and synthetic dyes like xylenol blue, bromothymol blue, and bromocresol purple have shown considerable promise for quick colourimetric detection of wound infection. Remote monitoring and telemedicine applications are made possible by the objective, quantitative, and non-invasive evaluation of wound progression made possible by integration with smartphone-assisted RGB picture analysis. Furthermore, a significant step toward precision wound care is represented by multifunctional theranostic hydrogels that combine wearable biosensing technologies, antimicrobial drug delivery, antioxidant activity, tissue regeneration, and infection sensing. Widespread clinical translation is still hampered by issues with long-term indicator stability, mechanical durability, large-scale production, clinical validation, and regulatory licensing, despite these encouraging advancements. Conclusion Colour-changing smart hydrogels are a new class of intelligent wound dressings that integrate digital health technology, stimuli-responsive therapeutic delivery, and real-time infection monitoring on one platform. It is anticipated that future developments in biomaterials, nanotechnology, wearable electronics, artificial intelligence, and smartphone-assisted diagnostics will hasten their clinical translation, enable precision-based, non-invasive, and customized wound care while enhancing patient compliance and lowering the cost of healthcare.