Sustainable bacterial cellulose-chitosan composite: A novel approach for the treatment of osteochondral defects

The treatment of osteochondral defects remains one of the most significant challenges in regenerative medicine due to the limited self-repair capacity of articular cartilage. This study proposes a multidisciplinary approach through the design and fabrication of an innovative biphasic scaffold (BS) that integrates a porous commercially pure titanium (c.p. Ti) substrate with a sustainable chitosan-bacterial cellulose (CS-BC) biocomposite. The metallic phase, produced via the space-holder technique with 60 vol% porosity, was engineered to replace damaged subchondral bone, while the biopolymeric phase was optimized to replicate the viscoelastic and biological performance of cartilage. To prevent post-operative infections that may lead to implant rejection, the scaffolds were functionalized with silver nanoparticles (AgNPs) through a dual incorporation approach involving both bulk loading and surface adsorption. Experimental results identified composite 11 (3% w/v CS, 10% w/w BC) as the most promising candidate, achieving a 99% crosslinking degree and a swelling capacity of approximately 400%. Mechanical characterization revealed that the inclusion of 10% w/w bacterial cellulose enhanced the elastic strain capacity to 9.7%, significantly improving the material's resilience compared to pure chitosan counterparts. Microbiological assays demonstrated sustained antibacterial efficacy against E. coli for up to 21 days and against S. aureus for at least 5 days. Furthermore, SEM analysis confirmed the successful infiltration of the biocomposite into the titanium pores, resulting in a unified hybrid platform that mimics the biomechanical and biofunctional requirements of native joint tissue. This synergistic system offers a promising solution for the long-term functional regeneration of complex osteochondral lesions.