Silk fibroin/hydroxyapatite scaffold: a highly compatible material for bone regeneration

How to Improve Physico-Chemical Properties of Silk Fibroin Materials for Biomedical Applications?-Blending and Cross-Linking of Silk Fibroin-A Review

This review supplies a report on fresh advances in the field of silk fibroin (SF) biopolymer and its blends with biopolymers as new biomaterials. The review also includes a subsection about silk fibroin mixtures with synthetic polymers. Silk fibroin is commonly used to receive biomaterials. However, the materials based on pure polymer present low mechanical parameters, and high enzymatic degradation rate. These properties can be problematic for tissue engineering applications. An increased interest in two- and three-component mixtures and chemically cross-linked materials has been observed due to their improved physico-chemical properties. These materials can be attractive and desirable for both academic, and, industrial attention because they expose improvements in properties required in the biomedical field. The structure, forms, methods of preparation, and some physico-chemical properties of silk fibroin are discussed in this review. Detailed examples are also given from scientific reports and practical experiments. The most common biopolymers: collagen (Coll), chitosan (CTS), alginate (AL), and hyaluronic acid (HA) are discussed as components of silk fibroin-based mixtures. Examples of binary and ternary mixtures, composites with the addition of magnetic particles, hydroxyapatite or titanium dioxide are also included and given. Additionally, the advantages and disadvantages of chemical, physical, and enzymatic cross-linking were demonstrated.

Advances in the Fabrication of Scaffold and 3D Printing of Biomimetic Bone Graft

The need for bone grafts is tremendous, and that leads to the use of autograft, allograft, and bone graft substitutes. The biology of the bone is quite complex regarding cellular composition and architecture, hence developing a mineralized connective tissue graft is challenging. Traditionally used bone graft substitutes including metals, biomaterial coated metals and biodegradable scaffolds, suffer from persistent limitations. With the advent and rise of additive manufacturing technologies, the future of repairing bone trauma and defects seems to be optimistic. 3D printing has significant advantages, the foremost of all being faster manipulation of various biocompatible materials and live cells or tissues into the complex natural geometries necessary to mimic and stimulate cellular bone growth. The advent of new-generation bioprinters working with high-precision, micro-dispensing and direct digital manufacturing is aiding in ground-breaking organ and tissue printing, including the bone. The future bone replacement for patients holds excellent promise as scientists are moving closer to the generation of better 3D printed bio-bone grafts that will be safer and more effective. This review aims to summarize the advances in scaffold fabrication techniques, emphasizing 3D printing of biomimetic bone grafts.

Antibacterial biomaterials in bone tissue engineering

Bone infection is a devastating disease characterized by recurrence, drug-resistance, and high morbidity, that has prompted clinicians and scientists to develop novel approaches to combat it. Currently, although numerous biomaterials that possess excellent biocompatibility, biodegradability, porosity, and mechanical strength have been developed, their lack of effective antibacterial ability substantially limits bone-defect treatment efficacy. There is, accordingly, a pressing need to design antibacterial biomaterials for effective bone-infection prevention and treatment. This review focuses on antibacterial biomaterials and strategies; it presents recently reported biomaterials, including antibacterial implants, antibacterial scaffolds, antibacterial hydrogels, and antibacterial bone cement types, and aims to provide an overview of these antibacterial materials for application in biomedicine. The antibacterial mechanisms of these materials are discussed as well.

UV-assisted synthesis of hydroxyapatite from eggshells at ambient temperature: cytotoxicity, drug delivery and bioactivity

Hydroxyapatite [Ca10(PO4)6(OH)2], an important biomaterial, retains a chemical structure that is similar to the mineral phase of bone. Consequently, the ability of hydroxyapatite (Hap) to augment bone growth within bone tissue has made it a potential candidate for use as a hard tissue-implant material. In this work, adopting a UV-mediated solid-state method for the first time, hydroxyapatite was synthesized from eggshells and no thermal treatment was used but ambient temperature was maintained. This simple synthesis process involved a combination of ball milling of the starting materials followed by UV-irradiation. UV-excitation of the Ca and P precursors resulted in the desired Hap and X-ray diffraction (XRD), Fourier-transform infrared (FT-IR) and Raman spectroscopic techniques were used for characterization. The potency of UV-Hap as a biomaterial was examined via the bioactivity, cytotoxicity and the drug (ciprofloxacin) loading-releasing response, which was encouraging. The results of the cell viability assays complied an insignificant cytotoxicity and the simulated body fluid immersion test indicated the bioactivity was within the acceptable range. On the other hand, to better understanding the drug ejection and associated transport phenomenon, two kinetic models (Higuchi and Ritger-Peppas models) were used and a diffusion controlled ciprofloxacin release mechanism was observed using the Higuchi model. However, the experimental outcomes of a drug delivery response exposed UV-Hap as a favorable vehicle for drug loading and release. Hence, this research highlights the prospects of a UV-assisted synthesis method as a green route for the synthesis of Hap to be applied in biomedical fields.