Rejections of commercial bone implants have driven research in the biomaterials field to develop more biocompatible and less cytotoxic alternatives. This study aims to create composites based on oxidized bacterial cellulose (OBC) and strontium apatite (SrAp). These composites were produced through a biomimetic method using a simulated body fluid modified with strontium ions to enhance bioactivity and stabilize apatite within the biomaterial. The incorporation of SrAp into OBC membranes was confirmed by infrared spectroscopy and indicated by the appearance of a peak corresponding to phosphate group elongation (850 cm⁻¹). Quantification of strontium content by atomic absorption spectrometry revealed a concentration of 3359 ± 727 mg·g⁻¹ of Sr adsorbed onto the material surface after 7 days, beyond which no significant increase was observed. Scanning electron microscopy verified biomineralization through structural modifications, and X-ray diffraction showed that despite new peak appearances, the biomineralized membranes retained crystallinity similar to pure samples. The composite also demonstrated high cell viability for mouse osteoblasts and fibroblasts and a low mortality rate in brine shrimp Artemia (approximately 12.94 ± 4.77%). These findings suggest that these membranes have great potential for application in bone tissue engineering.

Alginate is a biocompatible polysaccharide matrix used for bioactive dressings with inherent healing properties. Most alginate dressings are produced as single-layer dressings. This study explores the potential of bilayer membranes to modulate drug release and enhance antimicrobial properties. We used alginate and chitosan loaded with simvastatin, an anti-inflammatory drug. One membrane comprised dense layers of both alginate and chitosan, while the other featured a dense alginate upper layer and a porous chitosan lower layer. The current study introduces a new approach in which a bilayer membrane is modeled instead of creating a polymeric blend between alginate and chitosan. The upper layer of the membrane contains only alginate loaded with simvastatin, while the bottom layer contains only chitosan. Another innovation is the study of the use of a porous lower layer of chitosan. Therefore, the association of these polymers in a bilayer and porous membrane gives advanced therapeutic dressings (with anti-inflammatory and antimicrobial properties intrinsic to the membrane) that are more efficient in the healing of complex wounds. Comprehensive characterization encompassed physicochemical, thermal, morphological, and mechanical properties. Microbiological tests were conducted using chitosan extract, and cytotoxicity evaluations were performed on fibroblast and keratinocyte cells. The results showed interlayer adhesion due to ionic interactions between alginate and chitosan surfaces. The drying process influenced the morphological and physicochemical features of the membranes. Simvastatin release profiles demonstrated sustained release over an extended period (approximately 60%–70% of the drug after 96 h). Storage assessments revealed that after six months, the membranes maintained around 98% of the initial simvastatin content. The antimicrobial activity test underscored the bacteriostatic efficacy of the chitosan porous layer, making it well-suited for infected wounds. Cell viability tests confirmed the non-cytotoxic nature of the films, highlighting their promising characteristics for treating diverse skin lesion types.

Cellulose acetate (CA)/strontium phosphate (SrP) hybrid coating has been proposed as an effective strategy to build up novel bone-like structures for bone healing since CA is soluble in most organic solvents. Strontium (Sr²⁺) has been reported as a potential agent to treat degenerative bone diseases due to its osteopromotive and antibacterial effects. Herein, bioactive hybrid composite SrP-based coatings (CASrP) were successfully produced for the first time. CASrP was synthesized via a modified biomimetic method (for 7—CA7dSrP, and 14 days—CA14dSrP), in which the metal ion Sr²⁺ was used in place of Ca²⁺ in the simulated body fluid. Energy-dispersive X-ray (EDX) and Fourier transform infrared spectroscopy (FTIR) analysis confirmed the SrP incorporation chemically in the CASrP samples. Atomic absorption spectroscopy (AAS) supported EDX data, showing Sr²⁺ adsorption into CA, and its significant increase with the augmentation of time of treatment (ca. 92%—CA7dSrP and 96%—CA14dSrP). An increment in coating porosity and the formation of SrP crystals were evidenced by scanning electron microscopy (SEM) images. X-ray diffraction (XRD) evidenced a greater crystallinity than CA membranes and a destabilization of CA14dSrP structure compared to CA7dSrP. The composites were extremely biocompatible for fibroblast and osteoblast cells. Cell viability (%) was higher either for CA7dSrP (48 h: ca. 92% and 115%) and CA14dSrP (48 h: ca. 88% and 107%) compared to CA (48 h: ca. 70% and 51%) due to SrP formation and Sr²⁺ presence in its optimal dose in the culture media (4.6–9 mg·L⁻¹). In conclusion, the findings elucidated here evidence the remarkable potential of CA7dSrP and CA14dSrP as bioactive coatings on the development of implant devices for inducing bone regeneration.