Skin wounds are not only an aesthetic concern but also pose great risks to quality of life and general health. As the most promising biomaterial, hydrogels are three-dimensional polymeric networks and have attracted intense research attention. Hydrogels have developed a diverse range of biomedical and biopharmaceutical applications, owing to their large water content, biocompatibility, tunable mechanical properties, and stimuli-responsiveness. Stimuli-responsive hydrogels are smart materials which exhibit gelation, structural, degradation, performance and function changes when treated with external stimulations. Using these hydrogels to prepare wound dressing is a rapidly growing research area and has exhibited encouraging healing outcomes in small animal models, especially for the treatment of chronic wounds, diabetic wounds, and persistent skin inflammations. The present work gives a detailed and critical analysis on the design strategies, gelation mechanisms, materials selection, stimuli-responsiveness, hydrogel degradation, drug release profiles, and treatment outcomes of wound dressings prepared by the hydrogels with sensitivity to temperature, pH, reactive oxygen species (ROS), glucose, enzymes, and lights. We summarize, analyze, and critically evaluate the most recent publications in this area to explain, compare, and assess why and how various synthetic and bio-polymers are utilized by materials scientists to develop the next generation of skin wound dressing and regeneration. Graphical abstract

Free flap surgery is currently the only successful method used by surgeons to reconstruct critical-sized defects of the jaw, and is commonly used in patients who have had bony lesions excised due to oral cancer, trauma, infection or necrosis. However, donor site morbidity remains a significant flaw of this strategy. Various biomaterials have been under investigation in search of a suitable alternative for segmental mandibular defect reconstruction. Hydrogels are group of biomaterials that have shown their potential in various tissue engineering applications, including bone regeneration, both through in vitro and in vivo pre-clinical animal trials. This review discusses different types of hydrogels, their fabrication techniques, 3D printing, their potential for bone regeneration, outcomes, and the limitations of various hydrogels in preclinical models for bone tissue engineering. This review also proposes a modified technique utilizing the potential of hydrogels combined with scaffolds and cells for efficient reconstruction of mandibular segmental defects.

Osseointegration is a crucial property of biomaterials used for bone defect repair. While titanium is the gold standard in craniofacial surgeries, various polymeric biomaterials are being explored as alternatives. However, polymeric materials can be bioinert, hindering integration with surrounding tissues. In this investigation, plasma ion immersion implantation (PIII)-treated polyether ether ketone (PEEK) and polyether ketone (PEK) implants were assessed in a sheep maxilla and mandible model. Defects were filled with PIII-treated PEEK and PEK implants, produced through fused filament fabrication (FFF) and selective laser sintering (SLS), respectively. Positive controls were grade 23 titanium implants via selective laser melting, while untreated PEEK implants served as negative controls. Surface analyses using scanning electron microscopy and atomic force microscopy revealed favorable properties. Osseointegration was qualitatively and quantitatively assessed at 8-, 10-, and 12-weeks post-implantation, showing significantly improved outcomes for both PIII-treated PEEK and PEK implants compared to untreated controls. The study suggests PIII treatment enhances FFF-printed PEEK’s osseointegration, and PIII-treated SLS-printed PEK achieves comparable osseointegration to 3D printed titanium. These findings underscore surface modification strategies’ potential for polymeric biomaterials, offering insights into developing alternative implant materials for craniofacial surgeries, with enhanced biocompatibility and osseointegration capabilities for improved clinical outcomes.

Segmental mandibular defects are a common problem in head and neck surgery. Osseous free flap transfer has revolutionized mandibular reconstruction; however, donor site morbidity remains a significant problem. Bone tissue engineering (BTE) employs strategies for reconstructing critical-sized bone defects, improving the patients’ quality of life. Scaffolds employed for BTE must be mechanically stable, osseointegrate with neighboring bone, and promote osteogenesis. The need for modified, hybrid constructs with a diversity of favorable characteristics is essential. This review focuses on the recent progresses in modulating the physiochemical properties and applications of biomaterials in BTE in the context of mandibular segmental defect repair. Graphical Abstract