Synergistic Effect of Growth Factor Releasing Polymeric Nanoparticles and Ultrasound Stimulation on Osteogenic Differentiation

Osteogenic Differentiation of Adipose Tissue-Derived Mesenchymal Stem Cells on Composite Polymeric Scaffolds: A Review

The mesenchymal stem cells (MSCs) are the fundamental part of bone tissue engineering for the emergence of reconstructive medicine. Bone tissue engineering has recently been considered a promising strategy for treating bone diseases and disorders. The technique needs a scaffold to provide an environment for cell attachment to maintain cell function and a rich source of stem cells combined with appropriate growth factors. MSCs can be isolated from adipose tissue (ASCs), bone marrow (BM-MSCs), or umbilical cord (UC-MSCs). In the present study, the potential of ASCs to stimulate bone formation in composite polymeric scaffolds was discussed and it showed that ASCs have osteogenic ability in vitro. The results also indicated that the ASCs have the potential for rapid growth, easier adipose tissue harvesting with fewer donor site complications and high proliferative capacity. The osteogenic differentiation capacity of ASCs varies due to the culture medium and the addition of factors that can change signaling pathways to increase bone differentiation. Furthermore, gene expression analysis has a significant impact on improving our understanding of the molecular pathways involved in ASCs and, thus, osteogenic differentiation. Adding some drugs, such as dexamethasone, to the biomaterial composite also increases the formation of osteocytes. Combining ASCs with scaffolds synthesized from natural and synthetic polymers seems to be an effective strategy for bone regeneration. Applying exopolysaccharides, such as schizophyllan, chitosan, gelatin, and alginate in composite scaffolds enhances the osteogenesis potential of ASCs in bone tissue regeneration.

Corticosteroid-loaded chitosan-based in-situ forming gel combined with microneedle technology for improvement of burn eschar wound healing

Burn is one of the most common skin injuries and accounts for 300,000 deaths annually. Debridement and antibiotic therapy are major burn treatments, however, as debridement is not always possible and many drugs have poor penetration into necrotic tissue, permeation enhancement is acquired. Another challenge is the short duration of topically applied drugs. This study aims to address both problems by combining in-situ forming gels and microneedles. A chitosan-based in-situ forming gel of hydrocortisone was applied to human burn eschar using microneedles. The formulation was optimized using Design-Expert software. Formulation characterization was done in terms of gelling time and temperature, thermal analysis, release phenomenon, rheology, texture analysis, and stability. Finally, animal studies on mice burn wound treatment were conducted. Results showed that optimized formulation controlled the drug release, and wherever microneedle was used, drug permeation and flux increased (P-value < 0.05). In all ex-vivo and in-vivo stages, gel plus microneedle (length of 1.5 mm and application mode of 2) produced the best results concerning increased flux and faster recovery of burn eschar. In conclusion, the in-situ forming gel with appropriate texture, quality, and stability in combination with microneedle can be a good candidate for the controlled release of drugs in third-degree burn eschars.

Nanoscale Contrast Agents for Ultrasound Imaging of Musculoskeletal System

Musculoskeletal ultrasound (MSKUS) has been recognized as an important method for the evaluation of diseases of the musculoskeletal system, and contrast-enhanced ultrasound (CEUS) technology is becoming an important branch of it. The development of novel materials and tiny nano-formulations has further expanded ultrasound contrast agents (UCAs) into the field of nanotechnology. Over the years, nanoscale contrast agents have been found to play an unexpected role in the integration of precise imaging for diagnosis and treatment of numerous diseases. It has been demonstrated that nanoscale UCAs (nUCAs) have advantages in imaging over conventional contrast agents, including superior biocompatibility, serum stability, and longer lifetime. The potential value of nUCAs in the musculoskeletal system is that they provide more reliable and clinically valuable guidance for the diagnosis, treatment, and follow-up of related diseases. The frontier of advances in nUCAs, their applications, and insights in MSKUS are reviewed in this paper.

Application Progress of Modified Chitosan and Its Composite Biomaterials for Bone Tissue Engineering

In recent years, bone tissue engineering (BTE), as a multidisciplinary field, has shown considerable promise in replacing traditional treatment modalities (i.e., autografts, allografts, and xenografts). Since bone is such a complex and dynamic structure, the construction of bone tissue composite materials has become an attractive strategy to guide bone growth and regeneration. Chitosan and its derivatives have been promising vehicles for BTE owing to their unique physical and chemical properties. With intrinsic physicochemical characteristics and closeness to the extracellular matrix of bones, chitosan-based composite scaffolds have been proved to be a promising candidate for providing successful bone regeneration and defect repair capacity. Advances in chitosan-based scaffolds for BTE have produced efficient and efficacious bio-properties via material structural design and different modifications. Efforts have been put into the modification of chitosan to overcome its limitations, including insolubility in water, faster depolymerization in the body, and blood incompatibility. Herein, we discuss the various modification methods of chitosan that expand its fields of application, which would pave the way for future applied research in biomedical innovation and regenerative medicine.