Ecofriendly multifunctional thiolated carboxymethyl chitosan-based 3D scaffolds with luminescent properties for skin repair and theragnostic of tissue regeneration

Luminescent biopolymers, namely carboxymethyl chitosan, have become a target of attention due to their potential for biomedical applications. In this context, biomaterials capable of improving theragnostic tissue regeneration and provide a tissue repair remain a challenge. This study introduces a new 3D scaffold based on two innovative thiolated carboxymethyl chitosan with cysteine (CMCCys) and 11-mercaptoundecanoic acid (CMCMerc) resulting in enhanced fluorescence of CMC for repair and theragnostic of tissue regeneration. Those thiolated CMCs were intensively characterized by spectroscopy techniques (FTIR, NMR), swelling degree, chemical stability (Gel-fraction, GF) and morphological analysis (SEM, microtomography, BET). In addition, the photoluminescence properties were evaluated and cytocompatibility was performed via in vitro bioassays. The results demonstrated that those scaffolds presented interconnected 3D porous (porosity > 80%), a great GF, and a high degree of thiolation (2%–11%). Furthermore, the spectroscopy analysis elucidated a significant disulfide bond formation, which guaranteed mechanical stability for applications in tissue engineering (elastic modulus, (22 ± 3) kPa and (35 ± 2) kPa, for CMCCys and CMCMerc, respectively). Additionally, the incorporation of thiol group improved the fluorescence of CMC and they presented cytocompatibility > 90%. Thus, for the first time, a multifunctional 3D CMC thiomer was produced for applications in repair and theragnostic of tissue regeneration.