Medical Polymers : Emerging Trends & Opportunities

Polymers/Biopolymers For Modern Wound Dressing

Wound dressing has remained challenging for some life threatening wounds such as Burning.

Wound dressing has remained challenging for some life-threatening wounds such as burning. Researchers have been engaged in looking for better solutions. A review paper given in the “Journal of Material Sciences & Engineering” ( web link for detailed paper Future Needs for Would Dressings)

Despite the various methods and materials for wound dressings, to date, no wound dressing fully satisfies the requirements of an ideal substitute for skin ECM (Extracellular Matrix ). Most wound dressings are limited by fast degradation, weak adhesiveness and absorption, lack of drug release properties, poor oxygen permeability, as well as not being able to prevent protein adhesion onto the wound dressing surface. It is urgent to design and fabricate wound dressings which can
address these problems simultaneously, thereby leading to improved wound management, creating an easy solution for wounds, and decreasing death rate induced by severe wounds and bleeding.

Modern Wound Dressing Materials

Synthetic polymers such as polyvinyldene floride (PVDF) and polypropylene (PP) have been widely used for wound dressing materials. Poly (ε-caprolactone) (PCL), polyethylene glycol (PEG), polyethylene oxide (PEO), polyurethane (PU), poly (vinyl alcohol) (PVA), poly (lactic acid) (PLA), and poly (lactic-co-glycolic acid) (PLGA) are frequently used synthetic materials that have been approved by Food and Drug Administration (FDA) for biomedical applications, due to their good biocompatibility, biodegradability and non-toxic properties. For example, PLGA is commercially available, inexpensive, biocompatible, biodegradable, and showed sustained drug release properties, making it the ideal candidate for drug delivery and other biomedical applications. Moreover, Porporato discovered that lactate played an important role in promoting angiogenesis and wound healing process, and concluded that PLGA to be the most suitable polymer to provide lactate for enhanced wound management. PEG displays excellent biocompatibility, biodegradability, hydrophilicity and wettability. It is inexpensive and readily available, and therefore widely used for biomedical applications. More recently, Kim has shown that PEG provides antifouling properties, preventing the adsorption of protein and other biomolecules on to nanofiber surface, which enhances drug release properties and aids in maintenance of nanofiber surface properties during use. Hydrogels and nanofibrous scaffolds based on these synthetic polymers have been fabricated for biomedical applications with good mechanical properties.

However, the application of these synthetic polymers alone as wound dressings are limited by their adhesive properties and their ability to accelerate wound healing process.

Therefore, it is critical to produce a new and improved wound dressing by synthesizing, modifying, and systematically designing wound dressing materials with good mechanical properties while accelerating the healing process at molecular, cellular and systematic levels. It is also desirable for wound dressings to have good drug release properties to further promote the wound healing process. Detailed research article is given at the following web link.

Polymeric Biomaterials For 3D Printing In Medicine

Although much progress has been made with 3D printing technology, there are still remarkable issues to overcome (such as standardization and integration of an entire biofabrication platform, software design, capabilities of the 3D printers, reproducibility, quality by design, biomaterials characterization, and regulatory hurdles) before it can be recognized as a conventional biofabrication technique in medicine and reach the medical market. Among these issues, the major bottleneck is the lack of heterogeneity biomaterials allowing their reliable clinical use.

Generally, printable materials as polymers, hydrogels, or bioinks must: (1) have adequate viscosity that allows being printable and structurally stable, (2) have the capability to form 3D structure within a few minutes, (3) have the possibility of being mechanically reinforced through UV irradiation, biological (e.g. transglutaminase, sortase, tyrosinase, lysil-amine oxidase), or chemical (e.g. Michael-type addition, thiolene reaction, orthogonal reaction) cross-linking, (4) have tunable mechanical properties, (5) be biocompatible, (6) have adequate degradation kinetics, (7) form nontoxic degradation by product s , ( 8 ) be biomimetic, and (9) be able to control release molecules or drugs. In addition, biomaterial inks should be easily manufactured and processed, affordable, and commercially available.

In this context, 3D printing can transform healthcare through personalized medicine, thus improving patient compliance by tailoring the medication to the patient. This can be achieved through on-demand manufacturing in clinical settings to offer the best medical care.

3D printable materials Solid polymers-based inks

Polymers are the most common types of biomaterials used in 3D printing technologies [57, 58], since they come in the form of filaments for fused deposition modeling (FDM), powder-beads for selective laser sintering (SLS), solutions for stereolithography (SLA), and gels for direct ink writing (DIW) (Fig. 2). Further, they are biocompatible, have tunable mechanical properties, degradation rates, and can be dissolved in rapidly evaporating organic solvents such as dichloromethane, tetrahydrofuran or dimethyl sulfoxide.

Fig. . Schematic representation of 3D printing techniques. (a) Fused deposition modeling (FDM), (b) stereolithography (SLA), (c) selective laser sintering (SLS), and (d) direct ink writing (DIW). Table 1. Common polymers used in 3D printing and their properties

Polymers used in 3D printing technologies come in the form of filaments for fused deposition modeling (FDM), powder-beads for selective laser sintering (SLS), solutions for stereolithography (SLA), and gels for direct ink writing (DIW).