Ashkan Farazin

Hydroxyapatite (HAp), a naturally occurring calcium phosphate, remains one of the most promising bioceramics for orthopedic and dental applications due to its excellent biocompatibility, osteoconductivity, and structural similarity to natural bone mineral. While previous studies have explored HAp's basic properties, this review offers a comprehensive and integrated analysis of its synthesis methods, physicochemical properties, and biological performance, alongside critical comparisons and future‐oriented insights. A key novelty of this review is the incorporation of a 3PM analysis evaluating prior art, publications, products, and megatrends to assess translational readiness and strategic value. Furthermore, the review uniquely highlights biowaste‐derived HAp, sustainability implications in alignment with United Nations Sustainable Development Goals, and the underrepresented role of analytical and simulation models in HAp optimization. By connecting material science with ecological balance, cost‐effectiveness, and long‐term clinical potential, this review serves as a strategic roadmap for the next generation of HAp‐based biomaterials in regenerative medicine.

Bone tissue engineering (BTE) represents a cutting-edge approach to treating critical-sized bone defects, complex fractures, and degenerative bone diseases by promoting the regeneration of functional bone tissue. A crucial element in this process is the design and optimization of scaffolds that emulate the natural extracellular matrix (ECM), supporting cell adhesion, proliferation, and differentiation necessary for bone regeneration. Polymers are widely used in scaffold fabrication. They offer versatility, biocompatibility, and tunable properties that are essential for tissue engineering. This paper provides a comprehensive analysis of polymeric scaffolds in BTE, focusing on synthetic and natural polymers, composite scaffold designs, and the fabrication techniques employed to enhance their performance. Key design criteria, such as scaffold porosity, mechanical properties, and biodegradability, are discussed in the context of facilitating optimal bone regeneration. Additionally, we explore functionalization strategies to improve biological interactions, such as the incorporation of growth factors and surface modifications, and evaluate in vivo performance to highlight clinical potential. The paper also addresses current challenges, including the need for enhanced mechanical strength and controlled degradation, while offering insights into future directions for the development of polymeric scaffolds in bone tissue regeneration therapies.

Bone repair is a complex biological process requiring dynamic interplay between cellular mechanisms, molecular signaling, and environmental factors. The intricate stages of bone healing, including hematoma formation, inflammation, soft callus development, and hard callus remodeling, are driven by coordinated cellular responses and molecular pathways. Proinflammatory cytokines, growth factors, and the extracellular matrix play critical roles in promoting osteogenesis and angiogenesis. Factors such as age, systemic health, and mechanical stability significantly influence repair efficiency. To address limitations in natural healing, advancements in regenerative medicine have introduced innovative materials like nanocomposite hydrogels, which mimic the natural bone microenvironment and enhance cellular function. Semi‐interpenetrating network (semi‐IPN) hydrogels have emerged as a promising tool for bone tissue engineering. Combining crosslinked and non‐crosslinked polymers, these hydrogels offer a balance of mechanical stability, biological functionality, and controlled degradation. Semi‐IPN hydrogels provide structural support, facilitate cell attachment, and enable the sustained release of bioactive molecules. Their flexibility and adaptability make them suitable for encapsulating stem cells and promoting targeted bone regeneration. Moreover, nonsurgical and surgical scaffold delivery methods, ranging from injectable hydrogels to 3D‐printed and magnetically guided scaffolds, have expanded the horizons of bone repair strategies, reduced invasiveness, and improved patient outcomes. This review explores the dynamics of bone healing, the role of hydrogels in promoting regeneration, and the advanced construction strategies of semi‐IPN hydrogels for bone repair. By integrating polymer science, nanotechnology, and bioengineering, semi‐IPN hydrogels represent a transformative shift in addressing bone defects, paving the way for innovative therapeutic approaches in regenerative medicine. With ongoing advancements, these technologies hold significant potential to improve the effectiveness and accessibility of bone repair solutions.

Nanoparticles have emerged as a cornerstone of nanomedicine, offering transformative potential to modern healthcare through their multifunctional capabilities. Their adaptability positions them as ideal candidates for wound management, either as advanced wound dressings or as efficient drug delivery systems. With intrinsic antibacterial properties and the ability to enhance tissue repair, nanoparticles have gained significant attention in promoting effective wound healing. Biopolymer-based nanoparticles, derived from naturally sourced and synthetic materials such as proteins, polysaccharides, and polymers, including collagen, chitosan, alginate, polycaprolactone, and polylactic acid, stand out due to their unique combination of biodegradability and biocompatibility. These attributes make them particularly suited for addressing the challenges of wound care. Moreover, nanofibers incorporated with biopolymer-based nanoparticles demonstrate superior antibacterial properties and wound healing effectiveness, comparable to the performance of silver nanoparticles. These advancements signify a transformative approach in wound healing therapies, facilitating targeted and personalized treatments that expedite tissue regeneration and enhance patient recovery. This review delves into biopolymer-based nanoparticles’ advancements, applications, and potential in revolutionizing wound healing.

Nanohydrogel wound healing refers to the use of nanotechnology-based hydrogel materials to promote the healing of wounds. Hydrogel dressings are made up of a three-dimensional network of hydrophilic polymers that can absorb and retain large amounts of water or other fluids. Nanohydrogels take this concept further by incorporating nanoscale particles or structures into the hydrogel matrix. These nanoparticles can be made of various materials, such as silver, zinc oxide, or nanoparticles derived from natural substances like chitosan. The inclusion of nanoparticles can provide additional properties and benefits to the hydrogel dressings. Nanohydrogels can be designed to release bioactive substances, such as growth factors or drugs, in a controlled manner. This allows for targeted delivery of therapeutics to the wound site, promoting healing and reducing inflammation. Nanoparticles can reinforce the structure of hydrogels, improving their mechanical strength and stability. Nanohydrogels often incorporate antimicrobial nanoparticles, such as silver or zinc oxide. These nanoparticles have shown effective antimicrobial activity against a wide range of bacteria, fungi, and other pathogens. By incorporating them into hydrogel dressings, nanohydrogels can help prevent or reduce the risk of infection in wounds. Nanohydrogels can be designed to encapsulate and release bioactive substances, such as growth factors, peptides, or drugs, in a controlled and sustained manner. This targeted delivery of therapeutic agents promotes wound healing by facilitating cell proliferation, reducing inflammation, and supporting tissue regeneration. The unique properties of nanohydrogels, including their ability to maintain a moist environment and deliver bioactive agents, can help accelerate the wound healing process. By creating an optimal environment for cell growth and tissue repair, nanohydrogels can promote faster and more efficient healing of wounds.