Polymers For Tissue Engineering Research Articles

Biodegradable Conducting Polymer-Based Composites for Biomedical Applications-A Review.

In recent years, researchers have increasingly directed their focus toward the biomedical field, driven by the goal of engineering polymer systems that possess a unique combination of both electrical conductivity and biodegradability. This convergence of properties holds significant promise, as it addresses a fundamental requirement for biomedical applications: compatibility with biological environments. These polymer systems are viewed as auspicious biomaterials, precisely because they meet this critical criterion. Beyond their biodegradability, these materials offer a range of advantageous characteristics. Their exceptional processability enables facile fabrication into various forms, and their chemical stability ensures reliability in diverse physiological conditions. Moreover, their low production costs make them economically viable options for large-scale applications. Notably, their intrinsic electrical conductivity further distinguishes them, opening up possibilities for applications that demand such functionality. As the focus of this review, a survey into the use of biodegradable conducting polymers in tissue engineering, biomedical implants, and antibacterial applications is conducted.

The Development of Eco-Friendly Biopolymers for Use in Tissue Engineering and Drug Delivery

Tissue engineering and drug delivery have emerged as promising fields that hold the potential to revolutionize modern healthcare. The widespread use of synthetic polymers in these applications raises concerns about their environmental impact and biocompatibility. In response, researchers have shifted their focus toward the development of eco-friendly biopolymers as viable alternatives. This review paper aims to comprehensively analyze the progress made in the utilization of biopolymers for tissue engineering and drug delivery, with an emphasis on their ecological advantages and biomedical performance. The review begins by exploring the diverse sources of biopolymers, such as proteins, polysaccharides, and nucleic acids, derived from renewable resources, agricultural waste, etc. The discussion then delves into the unique properties of these biopolymers, including their biodegradability, nontoxic nature, and potential for controlled drug release. The incorporation of biopolymers in tissue engineering scaffolds is critically examined. The review also explores the role of biopolymers in the drug delivery systems, with a focus on nanoparticles, microparticles, hydrogels, and films. The capability of biopolymers to encapsulate and protect therapeutic agents, as well as their controlled release, is discussed in the context of targeted drug delivery and improved therapeutic outcomes. This paper highlights the challenges and future perspectives in the field of eco-friendly biopolymers for tissue engineering and drug delivery. Promising advancements in biofabrication techniques, nanotechnology, and personalized medicine are identified as key drivers for the rapid translation of these materials into the clinical applications. The development of eco-friendly biopolymers offers a sustainable and bio-safe alternative to the traditional synthetic polymers in tissue engineering and drug delivery. This comprehensive review underscores the crucial role of biopolymers in fostering advancements in regenerative medicine and therapeutic interventions while prioritizing environmental preservation and human health.

Bioinspired Polymers: Transformative Applications in Biomedicine and Regenerative Medicine.

Bioinspired polymers have emerged as a promising field in biomaterials research, offering innovative solutions for various applications in biomedical engineering. This manuscript provides an overview of the advancements and potential of bioinspired polymers in tissue engineering, regenerative medicine, and biomedicine. The manuscript discusses their role in enhancing mechanical properties, mimicking the extracellular matrix, incorporating hydrophobic particles for self-healing abilities, and improving stability. Additionally, it explores their applications in antibacterial properties, optical and sensing applications, cancer therapy, and wound healing. The manuscript emphasizes the significance of bioinspired polymers in expanding biomedical applications, addressing healthcare challenges, and improving outcomes. By highlighting these achievements, this manuscript highlights the transformative impact of bioinspired polymers in biomedical engineering and sets the stage for further research and development in the field.

The Influence of the Molecular Weight of Poly(Ethylene Oxide) on the Hydrolytic Degradation and Physical Properties of Polycaprolactone Binary Blends

The use of biodegradable polymers in tissue engineering has been widely researched due to their ability to degrade and release their components in a controlled manner, allowing for the potential regeneration of tissues. Melt blending is a common method for controlling the degradation rate of these polymers, which involves combining these materials in a molten state to create a homogenous mixture with tailored properties. In this study, polycaprolactone (PCL) was melt blended with hydrophilic poly (ethylene oxide) (PEO) of different molecular weights to assess its effect on PCL material performance. Hydrolytic degradation, thermal and viscoelastic properties, and surface hydrophilicity were performed to contrast the properties of the blends. DSC, DMA, and FTIR were performed on selected degraded PCL/PEO specimens following mass loss studies. The results showed that adding PEO to PCL reduced its melt viscosity-torque and melt temperature while increasing its hydrophilicity, optimizing PCL/PEO blend for soft tissue engineering applications and could contribute to the development of more effective and biocompatible materials for soft tissue regeneration.

Photocrosslinkable natural polymers in tissue engineering.

Natural polymers have been widely used in scaffolds for tissue engineering due to their superior biocompatibility, biodegradability, and low cytotoxicity compared to synthetic polymers. Despite these advantages, there remain drawbacks such as unsatisfying mechanical properties or low processability, which hinder natural tissue substitution. Several non-covalent or covalent crosslinking methods induced by chemicals, temperatures, pH, or light sources have been suggested to overcome these limitations. Among them, light-assisted crosslinking has been considered as a promising strategy for fabricating microstructures of scaffolds. This is due to the merits of non-invasiveness, relatively high crosslinking efficiency via light penetration, and easily controllable parameters, including light intensity or exposure time. This review focuses on photo-reactive moieties and their reaction mechanisms, which are widely exploited along with natural polymer and its tissue engineering applications.

Dendritic Polymers in Tissue Engineering: Contributions of PAMAM, PPI PEG and PEI to Injury Restoration and Bioactive Scaffold Evolution.

The capability of radially polymerized bio-dendrimers and hyperbranched polymers for medical applications is well established. Perhaps the most important implementations are those that involve interactions with the regenerative mechanisms of cells. In general, they are non-toxic or exhibit very low toxicity. Thus, they allow unhindered and, in many cases, faster cell proliferation, a property that renders them ideal materials for tissue engineering scaffolds. Their resemblance to proteins permits the synthesis of derivatives that mimic collagen and elastin or are capable of biomimetic hydroxy apatite production. Due to their distinctive architecture (core, internal branches, terminal groups), dendritic polymers may play many roles. The internal cavities may host cell differentiation genes and antimicrobial protection drugs. Suitable terminal groups may modify the surface chemistry of cells and modulate the external membrane charge promoting cell adhesion and tissue assembly. They may also induce polymer cross-linking for healing implementation in the eyes, skin, and internal organ wounds. The review highlights all the different categories of hard and soft tissues that may be remediated with their contribution. The reader will also be exposed to the incorporation of methods for establishment of biomaterials, functionalization strategies, and the synthetic paths for organizing assemblies from biocompatible building blocks and natural metabolites.

Biocompatible Synthetic Polymers for Tissue Engineering Purposes.

Synthetic polymers have been an integral part of modern society since the early 1960s. Besides their most well-known applications to the public, such as packaging, construction, textiles and electronics, synthetic polymers have also revolutionized the field of medicine. Starting with the first plastic syringe developed in 1955 to the complex polymeric materials used in the regeneration of tissues, their contributions have never been more prominent. Decades of research on polymeric materials, stem cells, and three-dimensional printing contributed to the rapid progress of tissue engineering and regenerative medicine that envisages the potential future of organ transplantations. This perspective discusses the role of synthetic polymers in tissue engineering, their design and properties in relation to each type of application. Additionally, selected recent achievements of tissue engineering using synthetic polymers are outlined to provide insight into how they will contribute to the advancement of the field in the near future. In this way, we aim to provide a guide that will help scientists with synthetic polymer design and selection for different tissue engineering applications.

Biopolymers advances in Medical Sciences: An Editorial Review

Biomaterials a term is used to describe the materials which are typically derived from any biological source. In generally it is said that these are the materials which are used within the human body to perform certain functions such as therapies1. The applications of polymers in the field of medicine have already gave birth to polymer science as a field. As we can see today, almost every polymer have been reported for use in any kind of clinical intervention, they are inseparable part of us now. Polymers are key players in clinical medicine as they are fundamental components of permanent prosthetic devices such as diameter vascular grafts, artificial lenses, catheters, hip implants etc., and the research is continued to perfect the performance and stability of polymers in vitro and in vivo2. However, the use of polymers in surgery is somewhat confined to connective tissue replacements. Interestingly, polymers have opened new horizons for drug delivery and gene therapy treatments such as nucleic-acid based drugs and protein-based drugs which cannot be taken up as typical pills, are providing impulsion for contemporary implantable polymers. The applications of polymers in tissue engineering are also gaining spotlight as these materials helps in the regeneration of 3D- (three-dimensional) organ and tissue structures.

Recent Advances in Bioplastics: Application and Biodegradation.

The success of oil-based plastics and the continued growth of production and utilisation can be attributed to their cost, durability, strength to weight ratio, and eight contributions to the ease of everyday life. However, their mainly single use, durability and recalcitrant nature have led to a substantial increase of plastics as a fraction of municipal solid waste. The need to substitute single use products that are not easy to collect has inspired a lot of research towards finding sustainable replacements for oil-based plastics. In addition, specific physicochemical, biological, and degradation properties of biodegradable polymers have made them attractive materials for biomedical applications. This review summarises the advances in drug delivery systems, specifically design of nanoparticles based on the biodegradable polymers. We also discuss the research performed in the area of biophotonics and challenges and opportunities brought by the design and application of biodegradable polymers in tissue engineering. We then discuss state-of-the-art research in the design and application of biodegradable polymers in packaging and emphasise the advances in smart packaging development. Finally, we provide an overview of the biodegradation of these polymers and composites in managed and unmanaged environments.

Novel Synthesis of Core-Shell Biomaterials from Polymeric Filaments with a Bioceramic Coating for Biomedical Applications

Bone tissue engineering is constantly in need of new material development with improved biocompatibility or mechanical features closer to those of natural bone. Other important factors are the sustainability, cost, and origin of the natural precursors involved in the technological process. This study focused on two widely used polymers in tissue engineering, namely polylactic acid (PLA) and thermoplastic polyurethane (TPU), as well as bovine-bone-derived hydroxyapatite (HA) for the manufacturing of core-shell structures. In order to embed the ceramic particles on the polymeric filaments surface, the materials were introduced in an electrical oven at various temperatures and exposure times and under various pressing forces. The obtained core-shell structures were characterized in terms of morphology and composition, and a pull-out test was used to demonstrate the particles adhesion on the polymeric filaments structure. Thermal properties (modulated temperature and exposure time) and the pressing force’s influence upon HA particles’ insertion degree were evaluated. More to the point, the form variation factor and the mass variation led to the optimal technological parameters for the synthesis of core-shell materials for prospect additive manufacturing and regenerative medicine applications.

Development of novel 3D scaffolds using BioExtruder by varying the content of hydroxyapatite and silica in PCL matrix for bone tissue engineering

Polycaprolactone (PCL) is considered as a most widely used biodegradable polymers in tissue engineering. But, PCL is also associated with certain limitations like, low stiffness, hydrophobic nature and limited cell affinity. These drawbacks are addressed in the present study by incorporating different wt% of silicon dioxide (SiO2) and hydroxyapatite (HAp) in the PCL matrix. 3D scaffolds were developed using a novel BioExtruder. The physicochemical properties, thermal stability and wettability of the composite scaffolds were studied systematically. Optical and Scanning Electron Microscopic images were analysed for morphological evaluation of the scaffolds. The pore size of the developed scaffolds increased from 290 to 315 μm with increasing SiO2 content, as examined by scanning electron microscope. An improved compressive modulus of 68.82 MPa was observed for 15 wt% SiO2 incorporated composite scaffold. The in-vitro degradation study of the composite scaffolds demonstrated an increase in the degradation rate for PCL/HAp scaffolds, while no significant change was observed for SiO2 incorporated scaffolds. Further, the cytotoxicity and cell proliferation studies were carried out using L929 Mouse Fibroblasts and MG-63 Osteoblasts respectively. The developed scaffolds revealed no toxic effects towards the cellular response and an increase in cell proliferation of ≥90% was observed during 7 days of cell culture. Thus, the scaffolds were proved to be potential candidate for bone tissue engineering application, particularly the scaffold with 10 wt% SiO2 incorporation into PCL/HAp (75/15) composite has resulted into higher cell proliferative % and improved mechanical strength.

Latent, Immunosuppressive Nature of Poly(lactic-co-glycolic acid) Microparticles.

Use of biomaterials to spatiotemporally control the activation of immune cells is at the forefront of biomedical engineering research. As more biomaterial strategies are employed for immunomodulation, understanding the immunogenicity of biodegradable materials and their byproducts is paramount in tailoring systems for immune activation or suppression. Poly(D,L-lactic-co-glycolic acid) (PLGA), one of the most commonly studied polymers in tissue engineering and drug delivery, has been previously described on one hand as an immune adjuvant, and on the other as a nonactivating material. In this study, the effect of PLGA microparticles (MPs) on the maturation status of murine bone marrow-derived dendritic cells (DCs), the primary initiators of adaptive immunity, was investigated to decipher the immunomodulatory properties of this biomaterial. Treatment of bone marrow-derived DCs from C57BL/6 mice with PLGA MPs led to a time dependent decrease in the maturation level of these cells, as quantified by decreased expression of the positive stimulatory molecules MHCII, CD80, and CD86 as well as the ability to resist maturation following challenge with lipopolysaccharide (LPS). Moreover, this immunosuppression was dependent on the molecular weight of the PLGA used to fabricate the MPs, as higher molecular weight polymers required longer incubation to produce comparable dampening of maturation molecules. These phenomena were correlated to an increase in lactic acid both intracellularly and extracellularly during DC/PLGA MP coculture, which is postulated to be the primary agent behind the observed immune inhibition. This hypothesis is supported by our results demonstrating that resistance to LPS stimulation may be due to the ability of PLGA MP-derived lactic acid to inhibit the phosphorylation of TAK1 and therefore prevent NF-κB activation. This work is significant as it begins to elucidate how PLGA, a prominent biomaterial with broad applications ranging from tissue engineering to pharmaceutics, could modulate the local immune environment and offers insight on engineering PLGA to exploit its evolving immunogenicity.

Knitted 3D Scaffolds of Polybutylene Succinate Support Human Mesenchymal Stem Cell Growth and Osteogenesis

Polybutylene succinate (PBS) is a biodegradable polyester with better processability and different mechanical properties compared to polylactides (PLAs), the most commonly used synthetic polymers in tissue engineering (TE). Since only few studies have evaluated PBS-containing materials for bone TE, we prepared PLA-PBS blends and analyzed material properties as well as cell attachment, proliferation, and osteogenic differentiation of human mesenchymal stem cells (hMSCs) on scaffolds. In addition to PLA, PBS, and PLA-PBS blends, PLA-polycaprolactone and PLA-poly(trimethylene carbonate) blends were evaluated. Polymer fibers were prepared using melt spinning. Pure PBS was observed to have the highest crystallinity and strain at break compared to the tougher PLA and PLA blends. No degradation occurred during the 4-week hydrolysis in either of the materials. Knitted and rolled scaffolds were manufactured, seeded with hMSCs, and cultured for 27 days. Human MSC viability was good on all the materials, but cell spreading along the fibers was only detected in PBS-containing scaffolds. They also induced the strongest proliferative response and osteogenic differentiation, which diminished with decreasing PBS content. Based on these results, PBS is superior to PLA with respect to hMSC attachment, proliferation, and osteogenesis. This encourages utilizing PBS-based biomaterials more widely in bone TE applications.

Chitosan: Application in tissue engineering and skin grafting

Tissue Engineering and skin grafting, an essential part of regenerative medicine is one of the fastest growing biomedical fields which could offer an important therapeutic strategy for management of hard to heal wounds. 2D and 3D polymeric scaffolds are prerequisites in this field to promote cell adhesion, proliferation and tissue regeneration. Convergence of technology and research has successfully unveiled unknown properties of Chitosan as a bioactive polymer. Natural abundance, cost effectiveness, biodegradability, biocompatibility and wound healing capabilities of chitosan and its derivatives has drawn the attention of many researchers for its use as an alternative for fabrication of a scaffold in tissue engineering and skin graft. However lower mechanical strength and solubility has limited its application in the biomedical field. It has been found that the derivatization and combination with other polymers can successfully overcome these limitations. This review focuses on the applicability of chitosan and its derivatives in combination with other polymers in tissue engineering and skin grafting along with the novel scaffold fabrication techniques. Studies so far have demonstrated the potential of chitosan and its derivative as a scaffold in the field of regenerative medicine. However, even if the promising results obtained from in-vitro and preclinical studies prove the efficacy of chitosan scaffolds it still has a long way to go to be used in clinical set ups.

Feasibility of chitosan-alginate (Chi-Alg) hydrogel used as scaffold for neural tissue engineering: a pilot study in vitro

ABSTRACTIn tissue engineering, scaffolding plays an important role in accommodating and stimulating new tissue growth. Chitosan and alginate are two widely used natural polymers in tissue engineering. Here, we prepared the chitosan-alginate (Chi-Alg) hydrogel from naturally derived chitosan and alginate polymers. The Fourier-transformed infrared spectroscopy and X-ray diffraction results demonstrated that a chitosan-alginate hydrogel was constructed due to the strong ionic interaction between the positively charged amino groups of chitosan and the negatively charged carboxyl groups of alginate. The scanning electron microscopy and contact angle results showed the inner porous structure and highly hydrophilic property of chitosan-alginate hydrogel. As the two most promising cell types in nerve tissue engineering, both olfactory ensheathing cells and neural stem cells proliferated well on the chitosan-alginate hydrogel. All results indicated the good potential application of a chitosan-alginate hydrogel for neural tissue engineering.

Inherently Antimicrobial Biodegradable Polymers in Tissue Engineering.

Many of the strategies currently being explored in the field of tissue engineering involve the combination of cells and degradable engineered scaffolds for the regeneration of biological tissues. However, infection of the wound or the scaffold itself results in failure of healing. Therefore, a new area of development in the field is the synthesis of polymer-based scaffolds that inherently have the ability to resist microbial infection as degradation occurs and new tissue replaces the scaffold. These scaffolds, defined as inherently antimicrobial biodegradable polymers (IABPs), can be classified based on their monomeric components as follows: (1) traditional antimicrobials (such as beta-lactams, fluoroquinolones, glycopeptides, and aminoglycosides), (2) naturally derived compounds (such as extracellular matrix components, chitosan, and antimicrobial peptides), and (3) novel synthetic antimicrobials. After validation of chemical synthesis as well as physicochemical characterization of a newly created IABP, thorough in vitro and in vivo assays must be conducted to ensure antimicrobial efficacy as well as biocompatibility as a tissue-engineered scaffold system. In this review, we will introduce existing IABPs, discuss the current platforms that have been developed for the synthesis of IABPs, and highlight future directions as well as challenges in the field.

Mass cultivation of UV-B adapted Arthrospira platensis RRGK under open raceway pond for the production of Poly-β-hydroxy butyrate

Six different strains of cyanobacteria were isolated from the freshwater lake, Arakkonam, India. Staining of cells with Nile Red showed the presence of large quantities of PHB granules in the cell cytoplasm of Arthrospira. Molecular identification of the strain was carried out using 16S rRNA analysis and their systematic position was ascertained as Arthrospira platensis RRGK. Studies were carried out on random mutagenesis approach using UV-B radiation for enhancing the production of PHB. Further, Response Surface Methodology was used for optimization of pH, temperature, and sodium bicarbonate for higher biomass and PHB production. Under open raceway pond A. platensis RRGK produced biomass concentration of 2.2±0.13gL−1 and 131±0.36gL−1 of PHB content. It was chemically characterized through FTIR, DSC, TGA and XRD analyses. Hence, PHB can be produced from cyanobacteria by sequestering harmful CO2. It can also be used as a substitute for synthetic polymers in tissue engineering.

Natural Polymers in Tissue Engineering

Natural Polymers in Tissue Engineering

Acoustic detection of cell adhesion to a coated quartz crystal microbalance – implications for studying the biocompatibility of polymers

Biocompatibility of polymers is an important parameter for the successful application of polymers in tissue engineering. In this work, quartz crystal microbalance (QCM) devices were used to follow the adhesion of NIH 3T3 fibroblasts to QCM surfaces modified with fibronectin (FN) and poly-D-lysine (PDL). The variations in sensor resonant frequency (Δf) and motional resistance (ΔR), monitored as the sensor signal, revealed that cell adhesion was favored in the PDL-coated QCMs. Fluorescence microscopy images of seeded cells showed more highly spread cells on the PDL substrate, which is consistent with the results of the QCM signals. The sensor signal was shown to be sensitive to extracellular matrix (ECM)-binding motifs. Ethylenediaminetetraacetic acid (EDTA) and soluble Gly-Arg-Gly-Asp-Ser (GRGDS) peptides were used to interfere with cell-ECM binding motifs onto FN-coated QCMs. The acquired acoustic signals successfully showed that in the presence of 30 mM EDTA or 1 mM GRGDS, cell adhesion is almost completely abolished due to the inhibition/blocking of integrin function by these compounds. The results presented here demonstrate the potential of the QCM sensor to study cell adhesion, to monitor the biocompatibility of polymers and materials, and to assess the effect of adhesion modulators. QCM sensors have great potential in tissue engineering applications, as QCM sensors are able to analyze the biocompatibility of surfaces and it has the added advantage of being able to evaluate, in situ and in real time, the effect of specific drugs/treatments on cells.

Poly(dopamine) coating to biodegradable polymers for bone tissue engineering

In this study, a technique based on poly(dopamine) deposition to promote cell adhesion was investigated for the application in bone tissue engineering. The adhesion and proliferation of rat osteoblasts were evaluated on poly(dopamine)-coated biodegradable polymer films, such as polycaprolactone, poly(l-lactide) and poly(lactic-co-glycolic acid), which are commonly used biodegradable polymers in tissue engineering. Cell adhesion was significantly increased to a plateau by merely 15 s of dopamine incubation, 2.2-4.0-folds of increase compared to the corresponding untreated substrates. Cell proliferation was also greatly enhanced by poly(dopamine) deposition, indicated by shortened cell doubling time. Mineralization was also increased on the poly(dopamine)-deposited surfaces. The potential of poly(dopamine) deposition in bone tissue engineering is demonstrated in this study.