Characterization of biodegradable polymers and their blends for biomedical applications 

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Currently we are characterizing the biodegradable polymers and their blends for biomedical applications. For biomedical applications, biodegradable polymers offer great potential for controlled drug delivery and wound management (e.g., adhesives, sutures, and surgical meshes), for orthopedic devices (screws, pins, and rods), and for dental applications (filler after tooth extraction) and tissue engineering. Depending on the applications, the degradation rate needs from a few days to a few years. Biopolymers and their blends are being studied to possess the desired properties with degradation rate. Our plan is to find the novel approaches to the characterization and assessment of PCL comprising blends, for example, tailored the blends from the viewpoint of their chemical, physical, and surface properties, so as to enable good cell adhesion and proliferation, maintenance their properties for a given time, and then degradation with no harmful effects in the body. We will modify the surface of PCL comprising blends by various treatment (e.g. plasma treatment) and observe the effect of adhesion and proliferation of human cells. Other commercially degradable polymers will be blended and a comparison will be made. Thus PCL comprising blends with improved properties and biocompatibility can be more effectively used as scaffolds for tissue engineering.

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(1). Dr. Yoichi Miyahara, a Professor of Physics at Texas State University (San Marcos) is willing to collaborate for a project on the “Characterization of the biopolymers and their blends for biomedical applications”. For the biomedical applications, especially in regenerative tissues and drug delivery system, a range of absorption rate is needed for a complete healing process. To tune the absorption rate from short to prolonged approximation of tissues under stress, binary blends of bio-compatible, biodegradable, bioactive and with complementary physical-mechanical-biological features will be analyzed. We prefer to analyze PDS/PCL blends; PDS is sensitive to thermal degradation, to enzymatic and chemical hydrolysis and has a good dissolution time, while PCL has higher thermal stability and longer degradation times than PDS. These blends with appropriate ratios and thermal treatment can be employed in regenerative tissues and drug delivery systems (i.e., bone and nerve regeneration, scaffolds, sutures, etc.). Additionally, the suture of a multi-strand, long chain ultra-high-molecular-weight polyethylene (UHMWPE) with a braided jacket of polyester will be blended with other biodegradable polymers and characterized their properties to provides strength, soft feel and abrasion resistance that is unequaled in orthopedic surgery. Dr. Mozammel Hussain, who is a lecturer in the same department of TSU are collaborate in this research work. My continuous research with PCL comprising blends (six articles) and very recent (2020) articles on bio-absorbable PDS monofilament surgical suture for blending with PCL inspire me to conduct research with biomedical polymers for my future endeavor.

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(2). Another project is ongoing with Florida State University in collaboration a research project involving “Melt structure and crystallization of biopolymers, copolymers and their blends for biomedical applications”. Biopolymer comprising binary blends will be investigated for application in regenerative medicine (bone and nerve regeneration, scaffolds, sutures, etc.), biodegradable medical devices (screws, plates, stents), as drug delivery, and as a material for tissue engineering. For biomedical applications, the final performance and residence time of a biodegradable device can be tailored by processing and introducing of copolymers and/or additives. Combining commercially available polymer sutures with other materials for example, bioactive glass powder or other copolymers offers new possibilities for the application of composite materials in tissue engineering. To improve the suture materials for a range of degradation time, the suture will be coated with glass powder and the tensile strength of the sutures will be tested before and after immersion in simulated body fluid (SBF) as a means to assess the effect of the bioactive glass coating on suture degradation.

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            The development of bio-polymers, copolymers and their blends for the biomedical application is one of the great challenges of research in materials science. Bio-absorbable polymers have been identified as alternative materials for biomedical applications since these polymers are degraded by simple hydrolysis to products that can be metabolized by the human body. Biomaterials are substances of natural or synthetic origins that can interact with biological systems on a temporary or permanent basis. These offer a possible alternative to treat and to repair the loss of tissues and organs from trauma or diseases. There are a lot of biomedical applications in which biomaterials are been used as a drug delivery system, cell scaffold and suture in tissue engineering, prostheses for tissue replacements like intraocular lens, dental implant, and breast implant, and artificial organs for temporary or permanent assist (e. g. artificial kidney, artificial heart, and vascular graft) (Cheng et al, 2009). Moreover, biomaterials are derived from biological sources in an eco-friendly way. Bio-sourced materials will gradually replace the currently existing family of oil-based polymers as they become cost- and performance-wise competitive (Lunelli et al, 2010). Variety materials have been used for medical care including metals, ceramics, and polymers. Biodegradable and bio-absorbable polymers have excellent characteristics for certain applications. Resorbable polymers gradually dissolve and are eliminated through the kidneys or other means. Among the biomaterials (biopolymers) used in the medical field, the polydioxanone (PDS), poly-caprolactone (PCL) and poly (lactic acid) (PLA) has received significant attention. PCL, PDS, PLA and its copolymers are being used in the biomedical area in the form of implants or devices due to its excellent biocompatibility and biodegradability (Mamun et al, 2018).

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            The project is divided into three parts. The first part of the work will be carried out in the Nanotechnology Research Lab, Department of Physics, university of Hafr Al Batin, Saudi Arabia. The binary and ternary blends of biocompatible and biodegradable polymers, copolymers will be prepared through solution mixing process. In addition, novel a-olefin copolymer might be used in the blend and characterized with respect to their thermal, mechanical and surface properties. In this case, the selected antibacterial agents will be used as an additive to the blends, which in turn will be processed to form 2D and 3D tissue engineering scaffold structures and assessed for their use in various biomedical applications, thereby promising a new family of antibacterial materials.

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            The second part of the work will be performed in the Department of Physics and Engineering, Slippery Rock University, USA. The phase structure and optical microscopy studied will be performed in Professor Rizwan Mahmood's Lab. The annealing and chemical treatment will be also performed. In addition, novel copolymer a-olefin will be used and characterized with respect to their optical properties.

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            The third part of the work will be carried out by Dr. Roland Sebastien, PIMM, ENSAM/CNRS/CNAM, Paris, France, where most of the surface studies will be performed.

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References:

 

1. Cheng, Y., Deng, S., Chen, P. and Ruan, R., 2009, Polylactic acid (PLA) synthesis and modifications: a review. Frontiers of Chemistry in China, 4(3), 259-264.

2. Lunelli B. H., Lasprilla, A. J. R., Martinez G. A. R., Jardini A. L. and Maciel Filho R., 2010, Poly-Lactic Acid Production from Brazilian Renewable Feedstock for Application in Biomedical Devices. In: Latin American Congress of Artificial Organs and Biomaterials, v. 216-2.3.

3. Mamun, A.; Rahman, S. M.; Ronald, S.; and Mahmood, R., 2018, Impact of Molecular Weight on the Thermal Stability and the Miscibility of Poly(ε-caprolactone)/Polystyrene Binary Blends.  Published online in the Journal of Polymers and the Environment.

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Characterization of PCL comprising binary blends for biomedical applications (Collaboration with Professor Rizwan Mahmood)

Tissue Engineered scaffolds

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            An area of interest in tissue engineering is to develop biomimetic constructs that closely resembles the extracellular matrix (ECM) architecture. The idea is to allow cells to undergo minimum remodeling as tissue regenerates in vivo. The electrospun fibers with sizes in the range of few microns/nanometers and porous structure can make appropriate resemblance for the ECM. This may provide an excellent topographical guidance to cellular growth and migration. I will use different biodegradable and biopolymers to prepare scaffolds. These scaffolds will be tested with different types of cells, for different tissue engineering applications.

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Polymeric Mesh for Bio-medical Application

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            Many plastic items for medical use can be made from polypropylene because it can withstand the heat in an autoclave. Polypropylene mesh has been used for surgical and medical device applications, including hernia mesh, urinary incontinence slings, pelvic organ prolapse suspenders and skin tissue carriers. The Polypropylene Knitted Mesh fabrics are comprised of monofilament yarns engineered for the manufacture of textile fabrics. For using in a hernia and pelvic organ prolapse repair operations to protect the body from new hernias in the same location. A small patch of the material is placed over the spot of a hernia, below the skin, and is painless. However, a polypropylene mesh will erode over the uncertain period from days to years. Therefore, the Food and Drug Administration (FDA) has issued several warnings on the use of polypropylene mesh medical kits for certain applications in pelvic organ prolapse, specifically when introduced in close proximity to the vaginal wall due to a continued increase in a number of mesh erosions reported by patients over the past few years. We are actively characterizing blends and developing new designs to meet the growing needs and trends in the biomedical field.