Polymeric Materials, Advances and Applications in Tissue Engineering: A Review

Incorporation of essential oils in polymeric films for biomedical applications

Natural and synthetic biodegradable polymers are widely used to obtain more sustainable films with biological, physicochemical, and mechanical properties for biomedical purposes. The incorporation of essential oils (EOs) in polymeric films can optimize the biological activities of these EOs, protect them from degradation, and serve as a prototype for new biotechnological products. This article aims to discuss updates over the last 10 years on incorporating EOs into natural and synthetic biodegradable polymer films for biomedical applications. Chitosan, alginates, cellulose, and proteins such as gelatine, silk, and zein are among the natural polymers most commonly used to prepare biodegradable films for release EOs. In addition to these, the most cited synthetic biodegradable polymers are poly(L-lactide) (PLA), poly(vinyl alcohol) (PVA), and poly(ε-caprolactone) (PCL). The EOs of clove, cinnamon, tea tree, eucalyptus, frankincense, lavender, thyme and oregano incorporated into polymeric films have been the most studied EOs in recent years in the biomedical field. Biomedical applications include antimicrobial activity against pathogenic bacteria and fungi, anticancer activity, potential for tissue engineering and regeneration with scaffolds and wound healing as dressings. Thus, this article reports on the importance of incorporating EOs into biodegradable polymer films, making these systems especially attractive for various biomedical applications.

3D Printing of Polysaccharide-Based Hydrogel Scaffolds for Tissue Engineering Applications: A Review

In tissue engineering, 3D printing represents a versatile technology employing inks to construct three-dimensional living structures, mimicking natural biological systems. This technology efficiently translates digital blueprints into highly reproducible 3D objects. Recent advances have expanded 3D printing applications, allowing for the fabrication of diverse anatomical components, including engineered functional tissues and organs. The development of printable inks, which incorporate macromolecules, enzymes, cells, and growth factors, is advancing with the aim of restoring damaged tissues and organs. Polysaccharides, recognized for their intrinsic resemblance to components of the extracellular matrix have garnered significant attention in the field of tissue engineering. This review explores diverse 3D printing techniques, outlining distinctive features that should characterize scaffolds used as ideal matrices in tissue engineering. A detailed investigation into the properties and roles of polysaccharides in tissue engineering is highlighted. The review also culminates in a profound exploration of 3D polysaccharide-based hydrogel applications, focusing on recent breakthroughs in regenerating different tissues such as skin, bone, cartilage, heart, nerve, vasculature, and skeletal muscle. It further addresses challenges and prospective directions in 3D printing hydrogels based on polysaccharides, paving the way for innovative research to fabricate functional tissues, enhancing patient care, and improving quality of life.

Natural rubber latex-based biomaterials for drug delivery and regenerative medicine: Trends and directions

Natural Rubber Latex (NRL) has shown to be a promising biomaterial for use as a drug delivery system to release various bioactive compounds. It is cost-effective, easy to handle, biocompatible, and exhibits pro-angiogenic and pro-healing properties for both soft and hard tissues. NRL releases compounds following burst and sustained release kinetics, exhibiting first-order release kinetics. Moreover, its pore density can be adjusted for tailored kinetics profiles. In addition, biotechnological applications of NRL in amblyopia, smart mattresses, and neovaginoplasty have demonstrated success. This comprehensive review explores NRL's diverse applications in biotechnology and biomedicine, addressing challenges in translating research into clinical practice. Organized into eight sections, the review emphasizes NRL's potential in wound healing, drug delivery, and metallic nanoparticle synthesis. It also addresses the challenges in enhancing NRL's physical properties and discusses its interactions with the human immune system. Furthermore, examines NRL's potential in creating wearable medical devices and biosensors for neurological disorders. To fully explore NRL's potential in addressing important medical conditions, we emphasize throughout this review the importance of interdisciplinary research and collaboration. In conclusion, this review advances our understanding of NRL's role in biomedical and biotechnological applications, offering insights into its diverse applications and promising opportunities for future development.

Biocompatibility of intraperitoneally implanted TEMPO-oxidized cellulose nanofiber hydrogels for antigen delivery in Atlantic salmon (Salmo salar L.) vaccines

Disease outbreaks are a major impediment to aquaculture production, and vaccines are integral for disease management. Vaccines can be expensive, vary in effectiveness, and come with adjuvant-induced adverse effects, causing fish welfare issues and negative economic impacts. Three-dimensional biopolymer hydrogels are an appealing new technology for vaccine delivery in aquaculture, with the potential for controlled release of multiple immunomodulators and antigens simultaneously, action as local depots, and tunable surface properties. This research examined the intraperitoneal implantation of a cross-linked TEMPO cellulose nanofiber (TOCNF) hydrogel formulated with a Vibrio anguillarum bacterin in Atlantic salmon with macroscopic and microscopic monitoring to 600-degree days post-implantation. Results demonstrated a modified passive integrated transponder tagging (PITT) device allowed for implantation of the hydrogel. However, the Atlantic salmon implanted with TOCNF hydrogels exhibited a significant foreign body response (FBR) compared to sham-injected negative controls. The FBR was characterized by gross and microscopic external and visceral proliferative lesions, granulomas, adhesions, and fibrosis surrounding the hydrogel using Speilberg scoring of the peritoneum and histopathology of the body wall and coelom. Acutely, gross monitoring displayed rapid coagulation of blood in response to the implantation wound with development of fibrinous adhesions surrounding the hydrogel by 72 h post-implantation consistent with early stage FBR. While these results were undesirable for aquaculture vaccines, this work informs on the innate immune response to an implanted biopolymer hydrogel in Atlantic salmon and directs future research using cellulose nanomaterial formulations in Atlantic salmon for a new generation of aquaculture vaccine technology.

Injectable Hydrogels for Nervous Tissue Repair-A Brief Review

The repair of nervous tissue is a critical research field in tissue engineering because of the degenerative process in the injured nervous system. In this review, we summarize the progress of injectable hydrogels using in vitro and in vivo studies for the regeneration and repair of nervous tissue. Traditional treatments have not been favorable for patients, as they are invasive and inefficient; therefore, injectable hydrogels are promising for the treatment of damaged tissue. This review will contribute to a better understanding of injectable hydrogels as potential scaffolds and drug delivery system for neural tissue engineering applications.

Poly(methyl methacrylate) in Orthopedics: Strategies, Challenges, and Prospects in Bone Tissue Engineering

Poly(methyl methacrylate) (PMMA) is widely used in orthopedic applications, including bone cement in total joint replacement surgery, bone fillers, and bone substitutes due to its affordability, biocompatibility, and processability. However, the bone regeneration efficiency of PMMA is limited because of its lack of bioactivity, poor osseointegration, and non-degradability. The use of bone cement also has disadvantages such as methyl methacrylate (MMA) release and high exothermic temperature during the polymerization of PMMA, which can cause thermal necrosis. To address these problems, various strategies have been adopted, such as surface modification techniques and the incorporation of various bioactive agents and biopolymers into PMMA. In this review, the physicochemical properties and synthesis methods of PMMA are discussed, with a special focus on the utilization of various PMMA composites in bone tissue engineering. Additionally, the challenges involved in incorporating PMMA into regenerative medicine are discussed with suitable research findings with the intention of providing insightful advice to support its successful clinical applications.

Development of Human-Derived Photocrosslinkable Gelatin Hydrogels for Tissue Engineering

Hydrogels are often used as biomimetic matrices for tissue regeneration. The source of the hydrogel is of utmost importance, as it affects the physicochemical characteristics and must be carefully selected to stimulate specific cell behaviors. Naturally derived polymeric biomaterials have inherent biological moieties, such as cell binding and protease cleavage sites, and thus can provide a suitable microenvironment for cells. Human-derived matrices can mitigate potential risks associated with the immune response and disease transmission from animal-derived biomaterials. In this article, we developed glycidyl methacrylate-modified human-derived gelatin (hGelGMA) hydrogels for use in tissue engineering applications. By adjusting the glycidyl methacrylate concentration in the reaction mixture, we synthesized hGelGMA with low, medium, and high degrees of modification referred to as hGelGMA-L, hGelGMA-M, and hGelGMA-H, respectively. The amount of polymeric networks in the hydrogels was increased proportionally with the degree of modification. This change has resulted in a decreasing trend in pore size, porosity, and consequent swelling ratio. Similarly, increasing the polymer concentration also exhibited slower enzymatic degradation. On the other hand, increasing the polymer concentration led to an improvement in mechanical properties, where the compressive moduli of hGelGMA-L, hGelGMA-M, and hGelGMA-H hydrogels have changed at 2.9 ± 1.0, 13.7 ± 0.9, and 26.4 ± 2.5 kPa, respectively. The cytocompatibility of hGelGMA was assessed by 3D encapsulation of human-derived cells, including human dermal fibroblasts (HDFs) and human mesenchymal stem cells (hMSCs), in vitro. Regardless of the degree of glycidyl methacrylate modification, the hGelGMA hydrogels preserved the viability of encapsulated cells and supported their growth and proliferation. HDF cells showed a higher metabolic activity in hGelGMA-H, while MSCs exhibited an increased metabolic activity when they were encapsulated in hGelGMA-M or hGelGMA-H. These results showed that photocrosslinkable human-derived gelatin-based hydrogels can be synthesized and their physical properties can be distinctly fine-tuned to different extents as a function of their degrees of modification depending on the needs of the target tissue. Due to its promising physical and biological properties, it is anticipated that hGelGMA can be utilized in a wide spectrum of tissue engineering applications.

Recent Advances in Functionalized Electrospun Membranes for Periodontal Regeneration

Periodontitis is a global, multifaceted, chronic inflammatory disease caused by bacterial microorganisms and an exaggerated host immune response that not only leads to the destruction of the periodontal apparatus but may also aggravate or promote the development of other systemic diseases. The periodontium is composed of four different tissues (alveolar bone, cementum, gingiva, and periodontal ligament) and various non-surgical and surgical therapies have been used to restore its normal function. However, due to the etiology of the disease and the heterogeneous nature of the periodontium components, complete regeneration is still a challenge. In this context, guided tissue/bone regeneration strategies in the field of tissue engineering and regenerative medicine have gained more and more interest, having as a goal the complete restoration of the periodontium and its functions. In particular, the use of electrospun nanofibrous scaffolds has emerged as an effective strategy to achieve this goal due to their ability to mimic the extracellular matrix and simultaneously exert antimicrobial, anti-inflammatory and regenerative activities. This review provides an overview of periodontal regeneration using electrospun membranes, highlighting the use of these nanofibrous scaffolds as delivery systems for bioactive molecules and drugs and their functionalization to promote periodontal regeneration.

Biodegradable Polymers in Biomedical Applications: A Review-Developments, Perspectives and Future Challenges

Biodegradable polymers are materials that, thanks to their remarkable properties, are widely understood to be suitable for use in scientific fields such as tissue engineering and materials engineering. Due to the alarming increase in the number of diagnosed diseases and conditions, polymers are of great interest in biomedical applications especially. The use of biodegradable polymers in biomedicine is constantly expanding. The application of new techniques or the improvement of existing ones makes it possible to produce materials with desired properties, such as mechanical strength, controlled degradation time and rate and antibacterial and antimicrobial properties. In addition, these materials can take virtually unlimited shapes as a result of appropriate design. This is additionally desirable when it is necessary to develop new structures that support or restore the proper functioning of systems in the body.

Nanotechnology development in surgical applications: recent trends and developments

This paper gives a detailed analysis of nanotechnology's rising involvement in numerous surgical fields. We investigate the use of nanotechnology in orthopedic surgery, neurosurgery, plastic surgery, surgical oncology, heart surgery, vascular surgery, ophthalmic surgery, thoracic surgery, and minimally invasive surgery. The paper details how nanotechnology helps with arthroplasty, chondrogenesis, tissue regeneration, wound healing, and more. It also discusses the employment of nanomaterials in implant surfaces, bone grafting, and breast implants, among other things. The article also explores various nanotechnology uses, including stem cell-incorporated nano scaffolds, nano-surgery, hemostasis, nerve healing, nanorobots, and diagnostic applications. The ethical and safety implications of using nanotechnology in surgery are also addressed. The future possibilities of nanotechnology are investigated, pointing to a possible route for improved patient outcomes. The essay finishes with a comment on nanotechnology's transformational influence in surgical applications and its promise for future breakthroughs.

A niche-mimicking polymer hydrogel-based approach to identify molecular targets for tackling human pancreatic cancer stem cells

BACKGROUND

Pancreatic adenocarcinoma (PAAD) is one of the most fatal human cancers, but effective therapies remain to be established. Cancer stem cells (CSCs) are highly resistant to anti-cancer drugs and a deeper understanding of their microenvironmental niche has been considered important to provide understanding and solutions to cancer eradication. However, as the CSC niche is composed of a wide variety of biological and physicochemical factors, the development of multidisciplinary tools that recapitulate their complex features is indispensable. Synthetic polymers have been studied as attractive biomaterials due to their tunable biofunctionalities, while hydrogelation technique further renders upon them a diversity of physical properties, making them an attractive tool for analysis of the CSC niche.

METHODS

To develop innovative materials that recapitulate the CSC niche in pancreatic cancers, we performed polymer microarray analysis to identify niche-mimicking scaffolds that preferentially supported the growth of CSCs. The niche-mimicking activity of the identified polymers was further optimized by polyethylene glycol (PEG)-based hydrogelation. To reveal the biological mechanisms behind the activity of the optimized hydrogels towards CSCs, proteins binding onto the hydrogel were analyzed by liquid chromatography with tandem mass spectrometry (LC-MS/MS), and the potential therapeutic targets were validated by looking at gene expression and patients' outcome in the TCGA database.

RESULTS

PA531, a heteropolymer composed of 2-methoxyethyl methacrylate (MEMA) and 2-(diethylamino)ethyl methacrylate (DEAEMA) (5.5:4.5) that specifically supports the growth and maintenance of CSCs was identified by polymer microarray screening using the human PAAD cell line KLM1. The polymer PA531 was converted into five hydrogels (PA531-HG1 to HG5) and developed to give an optimized scaffold with the highest CSC niche-mimicking activities. From this polymer that recapitulated CSC binding and control, the proteins fetuin-B and angiotensinogen were identified as candidate target molecules with clinical significance due to the correlation between gene expression levels and prognosis in PAAD patients and the proteins associated with the niche-mimicking polymer.

CONCLUSION

This study screened for biofunctional polymers suitable for recapitulation of the pancreatic CSC niche and one hydrogel with high niche-mimicking abilities was successfully fabricated. Two soluble factors with clinical significance were identified as potential candidates for biomarkers and therapeutic targets in pancreatic cancers. Such a biomaterial-based approach could be a new platform in drug discovery and therapy development against CSCs, via targeting of their niche.

Electrospun PVA Fibers for Drug Delivery: A Review

Innovation in biomedical science is always a field of interest for researchers. Drug delivery, being one of the key areas of biomedical science, has gained considerable significance. The utilization of simple yet effective techniques such as electrospinning has undergone significant development in the field of drug delivery. Various polymers such as PEG (polyethylene glycol), PLGA (Poly(lactic-co-glycolic acid)), PLA(Polylactic acid), and PCA (poly(methacrylate citric acid)) have been utilized to prepare electrospinning-based drug delivery systems (DDSs). Polyvinyl alcohol (PVA) has recently gained attention because of its biocompatibility, biodegradability, non-toxicity, and ideal mechanical properties as these are the key factors in developing DDSs. Moreover, it has shown promising results in developing DDSs individually and when combined with natural and synthetic polymers such as chitosan and polycaprolactone (PCL). Considering the outstanding properties of PVA, the aim of this review paper was therefore to summarize these recent advances by highlighting the potential of electrospun PVA for drug delivery systems.

Polymer Materials for Drug Delivery and Tissue Engineering

In recent years, the biomedical engineering field has seen remarkable advancements, focusing mainly on developing novel solutions for enhancing tissue regeneration or improving therapeutic outcomes [...].

Microstructured Polymeric Fabrics Modulating the Paracrine Activity of Adipose-Derived Stem Cells

The deposition of stem cells at sites of injury is a clinically relevant approach to facilitate tissue repair and angiogenesis. However, insufficient cell engraftment and survival require the engineering of novel scaffolds. Here, a regular network of microscopic poly(lactic-co-glycolic acid) (PLGA) filaments was investigated as a promising biodegradable scaffold for human Adipose-Derived Stem Cell (hADSC) tissue integration. Via soft lithography, three different microstructured fabrics were realized where 5 × 5 and 5 × 3 μm PLGA 'warp' and 'weft' filaments crossed perpendicularly with pitch distances of 5, 10 and 20 μm. After hADSC seeding, cell viability, actin cytoskeleton, spatial organization and the secretome were characterized and compared to conventional substrates, including collagen layers. On the PLGA fabric, hADSC re-assembled to form spheroidal-like structures, preserving cell viability and favoring a nonlinear actin organization. Moreover, the secretion of specific factors involved in angiogenesis, the remodeling of the extracellular matrix and stem cell homing was favored on the PLGA fabric as compared to that which occurred on conventional substrates. The paracrine activity of hADSC was microstructure-dependent, with 5 μm PLGA fabric enhancing the expression of factors involved in all three processes. Although more studies are needed, the proposed PLGA fabric would represent a promising alternative to conventional collagen substrates for stem cell implantation and angiogenesis induction.