Critical Review of Biodegradable and Bioactive Polymer Composites for Bone Tissue Engineering and Drug Delivery Applications

In the determination of the bioavailability of drugs administered orally, the drugs’ solubility and permeability play a crucial role. For absorption of drug molecules and production of a pharmacological response, solubility is an important parameter that defines the concentration of the drug in systemic circulation. It is a challenging task to improve the oral bioavailability of drugs that have poor water solubility. Most drug molecules are either poorly soluble or insoluble in aqueous environments. Polymer nanocomposites are combinations of two or more different materials that possess unique characteristics and are fused together with sufficient energy in such a manner that the resultant material will have the best properties of both materials. These polymeric materials (biodegradable and other naturally bioactive polymers) are comprised of nanosized particles in a composition of other materials. A systematic search was carried out on Web of Science and SCOPUS using different keywords, and 485 records were found. After the screening and eligibility process, 88 journal articles were found to be eligible, and hence selected to be reviewed and analyzed. Biocompatible and biodegradable materials have emerged in the manufacture of therapeutic and pharmacologic devices, such as impermanent implantation and 3D scaffolds for tissue regeneration and biomedical applications. Substantial effort has been made in the usage of bio-based polymers for potential pharmacologic and biomedical purposes, including targeted deliveries and drug carriers for regulated drug release. These implementations necessitate unique physicochemical and pharmacokinetic, microbiological, metabolic, and degradation characteristics of the materials in order to provide prolific therapeutic treatments. As a result, a broadly diverse spectrum of natural or artificially synthesized polymers capable of enzymatic hydrolysis, hydrolyzing, or enzyme decomposition are being explored for biomedical purposes. This summary examines the contemporary status of biodegradable naturally and synthetically derived polymers for biomedical fields, such as tissue engineering, regenerative medicine, bioengineering, targeted drug discovery and delivery, implantation, and wound repair and healing. This review presents an insight into a number of the commonly used tissue engineering applications, including drug delivery carrier systems, demonstrated in the recent findings. Due to the inherent remarkable properties of biodegradable and bioactive polymers, such as their antimicrobial, antitumor, anti-inflammatory, and anticancer activities, certain materials have gained significant interest in recent years. These systems are also actively being researched to improve therapeutic activity and mitigate adverse consequences. In this article, we also present the main drug delivery systems reported in the literature and the main methods available to impregnate the polymeric scaffolds with drugs, their properties, and their respective benefits for tissue engineering.

VIRAL DELIVERY USING SCAFFOLDS

In experimental oncology there are multiple approaches have been developed to target tumor cells. Many of them are based on scaffolds, a 3D models that mimics the structure of tissue in normal and pathophysiological state. It is known that to deliver a viral load to target cells, cells-carriers undergo limited differentiation, and premature aging. Since viral agents require cells to be in specific proliferative state, the delivery of the virus to the target cell is the main goal of the functional framework such as scaffold. Over decade, multiple studies demonstrate the production of scaffolds using matrigel, polyalacinic acid, poly-lactide-co-glycolide, vinyl stilbens, or bioactive polymers. Our review will describe the potential benefits of delivering the viral vector using 3D scaffolds for virus-mediated expression of biologically active substances that prevent angiogenesis, neoplasm proliferation, or, conversely, stimulate wound healing. 3D materials such as hydrogels and scaffolds are among the key innovations in the field of material chemistry. Moreover, viral vectors provide specific delivery of genes to target cells. However, the immunogenicity of a viral capsid consisting of viral proteins hinders the clinical use of such vectors widely. These limitations can be surmounted by using scaffolds. Therefore, our review might interest researchers working in the fields of chemistry, materials science and natural sciences, as well as in the field of bioengineering and medical technologies.

Soft chemical processing approach for the valorization of seafood waste by-products as a source of bioactive polymers

Chitin and chitosan as green and active biomacromolecules were extracted from local seafood waste (shrimp shells). The extraction was carried out by a soft chemical process, followed by structural characterization (FTIR, XRD, viscosity average molecular weight M̅v), thermal stability by TGA, and antibacterial tests. FTIR and XRD spectra confirmed the chemical structures of the extracted chitin and chitosan which were similar to the commercial ones. The chitin and chitosan had an average viscosimetric molar weight of 232.21 kDa and 41 kDa, respectively. The chitosan had a high deacetylation degree (DD = 71 %) and low cristallinity index (Icr = 68.3 %); compared to chitin, which exhibited a lower deacetylation degree (DD = 24.27 %), higher thermal stability and higher cristallinity index (Icr = 87.55 %). A bacteriostatic effect of chitin was observed in the gram-negative bacteria, Escherichia coli, Salmonella typhimurium. Chitosan exhibited a bacteriostatic effect on all bacteria tested, except Salmonella typhimurium.

Tailoring the Nitric Oxide Release with Additive Manufacturing to Create Antimicrobial Surfaces

Current use of implantable and indwelling medical devices have restricted life due to potential microbial colonization leading to severe ailments. The aim of this work is to develop bioactive polymers...

Hyaluronic acid as a bioactive component for bone tissue regeneration: Fabrication, modification, properties, and biological functions

Hyaluronic acid (HA) is widely distributed in the human body, and it is heavily involved in many physiological functions such as tissue hydration, wound repair, and cell migration. In recent years, HA and its derivatives have been widely used as advanced bioactive polymers for bone regeneration. Many medical products containing HA have been developed because this natural polymer has been proven to be nontoxic, noninflammatory, biodegradable, and biocompatible. Moreover, HA-based composite scaffolds have shown good potential for promoting osteogenesis and mineralization. Recently, many HA-based biomaterials have been fabricated for bone regeneration by combining with electrospinning and 3D printing technology. In this review, the polymer structures, processing, properties, and applications in bone tissue engineering are summarized. The challenges and prospects of HA polymers are also discussed.