Leather waste-derived carbon quantum dot-embedded hydrogels with bioinspired hair-like architectures: multifunctional integration for mechanosensing, pH monitoring, and antimicrobial/antioxidant applications

Abstract

Conventional leather manufacturing converts only ~ 20% of raw animal hides into finished products, leaving the majority underutilized and generating substantial waste. To improve resource valorization and realize the high-value potential of leather waste, we propose an innovative "waste upgrading-function integration" strategy, transforming discarded leather into high-value carbon dots via a one-pot hydrothermal process. The resulting waste leather-based carbon quantum dots (W-CQDs) exhibited uniform particle size (~ 8.26 nm), high fluorescence quantum yield (66.3%), semiconductor-like behavior (band gap: 4.25 eV), and a positively charged surface (ζ-potential: +16.6 mV). These physicochemical properties endowed W-CQDs with remarkable antibacterial activity (most effective against E. coli and S. aureus at 6 mg/mL), strong antioxidant capability, and low biotoxicity. By integrating W-CQDs into a polyacrylamide (PAM) network and engineering a biomimetic hair-like microstructure, we developed a W-CQDs/PAM hydrogel sensor with excellent mechanosensitivity (gauge factor: 2.67), rapid response (468–476 ms), and long-term stability (> 1000 cycles). Furthermore, the W-CQDs/PAM hydrogel exhibited pH-responsive fluorescence (pH 3 ~ 11) through intramolecular charge transfer (ICT) and aggregation-induced emission (AIE) mechanisms. Incorporation of LiBr further enhanced water retention and antifreeze performance, significantly expanding its potential for real-world sensing applications.

Graphical Abstract

Keywords

Waste-leather scraps / Carbon quantum dots / Hydrogel / Flexible sensors / Multifunctional integration

References

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Funding

National Natural Science Foundation of China(22278259)

RIGHTS & PERMISSIONS

The Author(s)