Biomaterials for Tissue Engineering Applications and Current Updates in the Field: A Comprehensive Review

Evaluation of the Effectiveness of Chitosan-Modified Bone Regeneration Materials: A Systematic Review

Background/Objectives: Today, regenerative therapy is routinely utilized in both medical and dental practices. Its outstanding results are due to the continuous development of technology and the invention of modern, more advanced biomaterials. The overarching idea in current regenerative therapy has shifted in the direction of the materials applied being osseointegrative, bioactive, responsive to stimuli from the body and actively promoting the overall regeneration of natural bone tissue. The aim is to determine whether chitosan is a material capable of improving the biological properties of different types of bone regeneration materials and, if so, which biological properties are affected. Methods: After going through the eligibility criteria, twenty articles, with a total of seventeen in vitro studies and six in vivo studies (some articles consisting of both), were included in this study. Results: The results presented colorimetric assays as the most commonly used methods investigating biological properties in in vitro studies, while in in vivo studies, researchers mainly rely on radiological and histological evaluation. After analyzing the data in this systematic review, it is clear that in vitro studies found a clear advantage of the results of chitosan-modified bone grafts in terms of bioactivity, osteogenic potential, biomineralization potential, biodegradability and antibacterial activity. In in vivo studies, chitosan-modified bone grafts stood out with better results in biocompatibility, osteogenic ability and biodegradability. Conclusions: In conclusion, it can be noted that chitosan-modified bone grafts have proven efficacy and the influence of chitosan is evidently favorable in terms of biological properties.

A Review on Bioengineering the Bovine Mammary Gland: The Role of the Extracellular Matrix and Reconstruction Prospects

The mammary gland is a modified sweat gland responsible for milk production. It is affected by diseases that reduce animals' quality of life, consequently leading to economic losses in livestock. With advancements in tissue bioengineering and regenerative medicine, studying the extracellular matrix (ECM) of the bovine mammary gland can improve our understanding of its physiology and the processes that affect it. This knowledge could also enable the development of sustainable therapeutic alternatives for both the dairy production chain and human oncology research. A common approach in regenerative medicine is decellularization, a process that removes all cells from tissue while preserving its architecture and ECM components for subsequent recellularization. The success of recellularization depends on obtaining immunologically compatible scaffolds and using appropriate cell culture sources and methods to ensure tissue functionality. However, tissue culture technology still faces challenges due to specific requirements and high costs. Here, we review the literature on biomaterials and tissue engineering, providing an overview of the ECM of the bovine mammary gland and advances in its bioengineering, with a focus on regenerative medicine for bovine species. The methodology employed consists of a structured search of scientific databases, including PubMed, Google Scholar, and SciELO, using specific keywords related to tissue engineering and the bovine mammary gland. The selection criteria prioritized peer-reviewed articles published between 2002 and 2025 that demonstrated scientific relevance and contributed to the understanding of bovine mammary gland bioengineering. Although research on this topic has advanced, vascularization, tissue maturation, and scalability remain key barriers to widespread application and economic viability.

Tissue Engineering and Regenerative Medicine: Perspectives and Challenges

From the pioneering days of cell therapy to the achievement of bioprinting organs, tissue engineering, and regenerative medicine have seen tremendous technological advancements, offering solutions for restoring damaged tissues and organs. However, only a few products and technologies have received United States Food and Drug Administration approval. This review highlights significant progress in cell therapy, extracellular vesicle-based therapy, and tissue engineering. Hematopoietic stem cell transplantation is a powerful tool for treating many diseases, especially hematological malignancies. Mesenchymal stem cells have been extensively studied. The discovery of induced pluripotent stem cells has revolutionized disease modeling and regenerative applications, paving the way for personalized medicine. Gene therapy represents an innovative approach to the treatment of genetic disorders. Additionally, extracellular vesicle-based therapies have emerged as rising stars, offering promising solutions in diagnostics, cell-free therapeutics, drug delivery, and targeted therapy. Advances in tissue engineering enable complex tissue constructs, further transforming the field. Despite these advancements, many technical, ethical, and regulatory challenges remain. This review addresses the current bottlenecks, emphasizing novel technologies and interdisciplinary research to overcome these hurdles. Standardizing practices and conducting clinical trials will balance innovation and regulation, improving patient outcomes and quality of life.

Application of Platelet-Rich Plasma-Based Scaffolds in Soft and Hard Tissue Regeneration

Platelet-rich plasma (PRP) is a blood product with higher platelet concentrations than whole blood, offering controlled delivery of growth factors (GFs) for regenerative medicine. PRP plays pivotal roles in tissue restoration mechanisms, including angiogenesis, fibroblast proliferation, and extracellular matrix development, making it applicable across various regenerative medicine treatments. Despite promising results in different tissue injuries, challenges such as short half-life and rapid deactivation by proteases persist. To address these challenges, biomaterial-based delivery scaffolds, such as sponges or hydrogels, have been investigated. Current studies exhibit that PRP-loaded scaffolds fix these issues due to the sustained release of GFs. In this regard, given the widespread application of PRP in clinical studies, the use of PRP-loaded scaffolds has drawn significant consideration in tissue engineering (TE). Therefore, this review briefly introduces PRP as a rich origin of GFs, its classification, and preparation methods and discusses PRP applications in regenerative medicine. This study also emphasizes and reviews the latest research on the using scaffolds for PRP delivery in diverse fields of TE, including skin, bone, and cartilage repair.

Poly(propylene fumarate) Composite Scaffolds for Bone Tissue Engineering: Innovation in Fabrication Techniques and Artificial Intelligence Integration

Over the past three decades, the biodegradable polymer known as poly(propylene fumarate) (PPF) has been the subject of numerous research due to its unique properties. Its biocompatibility and controllable mechanical properties have encouraged numerous scientists to manufacture and produce a wide range of PPF-based materials for biomedical purposes. Additionally, the ability to tailor the degradation rate of the scaffold material to match the rate of new bone tissue formation is particularly relevant in bone tissue engineering, where synchronized degradation and tissue regeneration are critical for effective healing. This review thoroughly summarizes the advancements in different approaches for PPF and PPF-based composite scaffold preparation for bone tissue engineering. Additionally, the challenges faced by each approach, such as biocompatibility, degradation, mechanical features, and crosslinking, were emphasized, and the noteworthy benefits of the most pertinent synthesis strategies were highlighted. Furthermore, the synergistic outcome between tissue engineering and artificial intelligence (AI) was addressed, along with the advantages brought by the implication of machine learning (ML) as well as the revolutionary impact on regenerative medicines. Future advances in bone tissue engineering could be facilitated by the enormous potential for individualized and successful regenerative treatments that arise from the combination of tissue engineering and artificial intelligence. By assessing a patient's reaction to a certain drug and choosing the best course of action depending on the patient's genetic and clinical characteristics, AI can also assist in the treatment of illnesses. AI is also used in drug research and discovery, target identification, clinical trial design, and predicting the safety and effectiveness of novel medications. Still, there are ethical issues including data protection and the requirement for reliable data management systems. AI adoption in the healthcare sector is expensive, involving staff and facility investments as well as training healthcare professionals on its application.

Biomaterials for Guided Tissue Regeneration and Guided Bone Regeneration: A Review

This review aims to provide an overview of the types of membranes, bone substitutes, and mucosal substitutes used for GTR and GBR and briefly explores recent innovations for tissue regeneration and their future perspectives. Since this is a narrative review, no systematic search, meta-analysis, or statistical analysis was conducted. Using biomaterials for GTR and GBR provides a reduction in postoperative morbidity, as it contributes to less invasive clinical procedures, serving as an alternative to autogenous grafts. Moreover, randomized clinical trials (RCTs) and systematic reviews are essential for the evaluation of new biomaterials. These studies provide more robust evidence and help guide clinical practice in the selection of safer and more effective biomaterials, allowing for the personalization of treatment protocols for each patient.

Bioprinted Hydrogels as Vehicles for the Application of Extracellular Vesicles in Regenerative Medicine

Three-dimensional bioprinting is a new advance in tissue engineering and regenerative medicine. Bioprinting allows manufacturing three-dimensional (3D) structures that mimic tissues or organs. The bioinks used are mainly made of natural or synthetic polymers that must be biocompatible, printable, and biodegradable. These bioinks may incorporate progenitor cells, favoring graft implantation and regeneration of injured tissues. However, the natures of biomaterials, bioprinting processes, a lack of vascularization, and immune responses are factors that limit the viability and functionality of implanted cells and the regeneration of damaged tissues. These limitations can be addressed by incorporating extracellular vesicles (EV) into bioinks. Indeed, EV from progenitor cells may have regenerative capacities, being similar to those of their source cells. Therefore, their combinations with biomaterials can be used in cell-free therapies. Likewise, they can complement the manufacture of bioinks by increasing the viability, differentiation, and regenerative ability of incorporated cells. Thus, the main objective of this review is to show how the use of 3D bioprinting technology can be used for the application of EV in regenerative medicine by incorporating these nanovesicles into hydrogels used as bioinks. To this end, the latest advances derived from in vitro and in vivo studies have been described. Together, these studies show the high therapeutic potential of this strategy in regenerative medicine.

Development of 4D-Printed Arterial Stents Utilizing Bioinspired Architected Auxetic Materials

The convergence of 3D printing and auxetic materials is paving the way for a new era of adaptive structures. Auxetic materials, known for their unique mechanical properties, such as a negative Poisson's ratio, can be integrated into 3D-printed objects to enable them to morph or deform in a controlled manner, leading to the creation of 4D-printed structures. Since the first introduction of 4D printing, scientific interest has spiked in exploring its potential implementation in a wide range of applications, from deployable structures for space exploration to shape-adaptive biomechanical implants. In this context, the current paper aimed to develop 4D-printed arterial stents utilizing bioinspired architected auxetic materials made from biocompatible and biodegradable polymeric material. Specifically, three different auxetic materials were experimentally examined at different relative densities, under tensile and compression testing, to determine their mechanical behavior. Based on the extracted experimental data, non-linear hyperelastic finite element material models were developed in order to simulate the insertion of the stent into a catheter and its deployment in the aorta. The results demonstrated that among the three examined structures, the 'square mode 3' structure revealed the best performance in terms of strength, at the same time offering the necessary compressibility (diameter reduction) to allow insertion into a typical catheter for stent procedures.

From Cartilage to Matrix: Protocols for the Decellularization of Porcine Auricular Cartilage

The shortage of tissues and damaged organs led to the development of tissue engineering. Biological scaffolds, created from the extracellular matrix (ECM) of organs and tissues, have emerged as a promising solution for transplants. The ECM of decellularized auricular cartilage is a potential tool for producing ideal scaffolds for the recellularization and implantation of new tissue in damaged areas. In order to be classified as an ideal scaffold, it must be acellular, preserving its proteins and physical characteristics necessary for cell adhesion. This study aimed to develop a decellularization protocol for pig ear cartilage and evaluate the integrity of the ECM. Four tests were performed using different methods and protocols, with four pig ears from which the skin and subcutaneous tissue were removed, leaving only the cartilage. The most efficient protocol was the combination of trypsin with a sodium hydroxide solution (0.2 N) and SDS (1%) without altering the ECM conformation or the collagen architecture. In conclusion, it was observed that auricular cartilage is difficult to decellularize, influenced by material size, exposure time, and the composition of the solution. Freezing and thawing did not affect the procedure. The sample thickness significantly impacted the decellularization time.

Aerogels Based on Chitosan and Collagen Modified with Fe2O3 and Fe3O4 Nanoparticles: Fabrication and Characterization

The necessity to mitigate the intrinsic issues associated with tissue or organ transplants, in order to address the rising prevalence of diseases attributable to increased life expectancy, provides a rationale for the pursuit of innovation in the field of biomaterials. Specifically, biopolymeric aerogels represent a significant advancement in the field of tissue engineering, offering a promising solution for the formation of temporary porous matrices that can replace damaged tissues. However, the functional characteristics of these materials are inadequate, necessitating the implementation of matrix reinforcement methods to enhance their performance. In this study, chemical and green iron oxide nanoparticles, previously synthesized and documented in existing research, were incorporated into hybrid aerogels combining collagen (C) and chitosan (CH). The characterization of these aerogels was conducted through rheological, microstructural, and functional analyses. The results demonstrate that the incorporation of iron oxide nanoparticles has a significant influence on the properties of the aerogels fabricated with them. In particular, the incorporation of these nanoparticles has been observed to modify the mechanical properties, with an increase in strength and porosity that may support cell proliferation.

Chitosan/vanillin/polydimethylsiloxane scaffolds with tunable stiffness for muscle cell proliferation

The mechanical properties of scaffolds can significantly influence cell behavior. We propose a methodology for producing chitosan and vanillin-crosslinked chitosan films with tunable mechanical properties to be applied as scaffolds for C2C12 myoblasts. In this approach, aqueous polydimethylsiloxane (PDMS) elastomeric dispersions were prepared using polysorbate 20 as emulsifier. These dispersions were then cured and incorporated into chitosan or vanillin-crosslinked chitosan polymeric dispersions at two different volume fractions (1 % and 10 %), followed by casting into films. Atomic force microscopy in force spectroscopy mode was used to characterize the mechanical properties of the swollen systems in PBS buffer. The mechanical properties of the chitosan and vanillin-crosslinked chitosan scaffolds were modulated by the incorporation of the elastomer. The elastic modulus (E) of chitosan-based scaffolds varied from 60 to 200 kPa, while for vanillin-based scaffolds, it ranged from 200 to 600 kPa with the addition of PDMS elastomers. A general trend observed was that the softest scaffolds exhibited the highest swelling degree and the lowest gel content. After 24 h, good cell viability was observed for chitosan and chitosan-PDMS scaffolds, whereas vanillin-based scaffolds showed borderline cytotoxicity (∼70 %). C2C12 cells demonstrated good adhesion on scaffolds with E values ranging from 114 to 568 kPa.

Methods for Assessing Scaffold Vascularization with Human Endothelial Cells

The success of tissue engineering relies heavily on the efficient and rapid formation of blood vessels in the newly engineered tissues. To achieve this, it is crucial to use scaffolds that not only support the survival of vascular cells but also facilitate the development and maturation of a capillary network in vivo. Utilizing advanced biomaterials and scaffold designs is essential to ensure that the engineered tissues can integrate effectively with the host tissues and maintain their functionality over time. Here, we present a method for generating endothelial cells from induced pluripotent stem cells and pre-vascularizing scaffolds by seeding them with endothelial cells in a 3D porous structure. These pre-vascularized scaffolds can then be implanted in a rat subcutaneous model to create vascularized tissue constructs. This approach holds great promise for generating clinically viable constructs that can be used in regenerative medicine and drug development.

Artificial intelligence in dentistry and dental biomaterials

Artificial intelligence (AI) technology is being used in various fields and its use is increasingly expanding in dentistry. The key aspects of AI include machine learning (ML), deep learning (DL), and neural networks (NNs). The aim of this review is to present an overview of AI, its various aspects, and its application in biomedicine, dentistry, and dental biomaterials focusing on restorative dentistry and prosthodontics. AI-based systems can be a complementary tool in diagnosis and treatment planning, result prediction, and patient-centered care. AI software can be used to detect restorations, prosthetic crowns, periodontal bone loss, and root canal segmentation from the periapical radiographs. The integration of AI, digital imaging, and 3D printing can provide more precise, durable, and patient-oriented outcomes. AI can be also used for the automatic segmentation of panoramic radiographs showing normal anatomy of the oral and maxillofacial area. Recent advancement in AI in medical and dental sciences includes multimodal deep learning fusion, speech data detection, and neuromorphic computing. Hence, AI has helped dentists in diagnosis, planning, and aid in providing high-quality dental treatments in less time.

Development of Biomimetic Substrates for Limbal Epithelial Stem Cells Using Collagen-Based Films, Hyaluronic Acid, Immortalized Cells, and Macromolecular Crowding

Despite the promising potential of cell-based therapies developed using tissue engineering techniques to treat a wide range of diseases, including limbal stem cell deficiency (LSCD), which leads to corneal blindness, their commercialization remains constrained. This is primarily attributable to the limited cell sources, the use of non-standardizable, unscalable, and unsustainable techniques, and the extended manufacturing processes required to produce transplantable tissue-like surrogates. Herein, we present the first demonstration of the potential of a novel approach combining collagen films (CF), hyaluronic acid (HA), human telomerase-immortalized limbal epithelial stem cells (T-LESCs), and macromolecular crowding (MMC) to develop innovative biomimetic substrates for limbal epithelial stem cells (LESCs). The initial step involved the fabrication and characterization of CF and CF enriched with HA (CF-HA). Subsequently, T-LESCs were seeded on CF, CF-HA, and tissue culture plastic (TCP). Thereafter, the effect of these matrices on basic cellular function and tissue-specific extracellular matrix (ECM) deposition with or without MMC was evaluated. The viability and metabolic activity of cells cultured on CF, CF-HA, and TCP were found to be similar, while CF-HA induced the highest (p < 0.05) cell proliferation. It is notable that CF and HA induced cell growth, whereas MMC increased (p < 0.05) the deposition of collagen IV, fibronectin, and laminin in the T-LESC culture. The data highlight the potential of, in particular, immortalized cells and MMC for the development of biomimetic cell culture substrates, which could be utilized in ocular surface reconstruction following further in vitro, in vivo, and clinical validation of the approach.

Mechanical Characterization of Polylactic Acid Composite Scaffolds Formed in Different Lattice Structures by Fused Deposition Modeling-Based 3D Printing

Scaffolds' designs and physical properties have an important place in tissue engineering. Using different biomaterials, scaffolds with other structures can be developed. The thermal and mechanical properties of biomaterials used in producing scaffolds with the fused deposition modeling method are significant for the application's success. The material must be suitable for both the production method and to be used as a scaffold. Therefore, this study designed three different scaffolds made of the same polylactic acid (PLA) material, but with different lattice structures. To determine the mechanical properties of PLA scaffolds formed, 800 N axial compression load at a 20 mm/min velocity was applied to the samples, with n = 3 in each group. To determine the stiffness of scaffolds, the stress-strain values were calculated by measuring the maximum displacement data under load in each group. Also, finite element analysis was performed on PLA scaffold models. At the same time, scanning electron microscope, differential thermal analysis-thermogravimetric analysis, differential scanning calorimetry, and X-ray powder diffraction pattern analyses were carried out. As a result, it has been concluded that the design significantly affects mechanical properties. Besides the material, the scaffold design is the most important parameter in tissue engineering studies.

Application of Nanostructures in Biology and Medicine

At present, nanomaterials are used in a wide range of applications in all spheres of civil needs, including energy, medicine, and industry [...].

Therapeutic Applications of Azo Dye Reduction: Insights From Methyl Orange Degradation for Biomedical Innovations

This paper emphasizes the possible application of methyl orange reduction as a therapeutic technique, highlighting the potential of azo dye reduction in biomedical fields. The generally used azo dyes are toxic and carcinogenic; hence, they implicitly threaten the environment and health. The degradation of methyl orange, a famous example of azo dyes, is used to describe the degradation process for other azo dyes. This work discusses the ability of different methyl orange degradation methods, focusing on biocatalysts and nanomaterials, among the methods that identified enzymatic degradation with azoreductase enzymes as the method that quickly breaks down azo dyes under mild conditions as the most appropriate method, as well as its specificity as environmentally friendly. Moreover, metal nanoparticles such as silver and gold impellers increase the reducing efficiency because they offer a pivotal surface for the reduction reactions that undergo electron transfer. The complete breakdown of methyl orange is essential in biomedical usage. The strategies for treating azo dye reduction can be extended to next-generation drug delivery systems (DDS), biosensors, and therapeutic agents. Organisms involved in degradation can be functionalized to selectively degrade specific cells or tissues, thus presenting a new targeted therapy. Knowledge of degradation pathways and non-toxic products is essential in creating programs that build better and more efficient therapeutic agents. This work endeavors to illustrate the development of enzymatic and nanomaterials-based approaches to achieve sustainable azo dye decolorisation to open the gateway to developing other biomedical applications that tend to promote environmental and health-friendly solutions.

Electrospun poly(lactic acid) membranes with defined pore size to enhance cell infiltration

Electrospun membranes are compact structures with small pore sizes that hinder cell infiltration, resulting in membranes with cells attached only to the external surface rather than throughout the entire volume. Thus, there is a need to increase the pore size of electrospun membranes maintaining their structural similarity to the extracellular matrix. In this work, we used glucose crystals embedded in polyethylene oxide (PEO) fibers to create large pores in poly(lactic acid) (PLA) electrospun membranes to allow for cellular infiltration. The PEO fibers containing glucose crystals of different sizes (>50, 50-100 and 100-150 μm) and in varying concentrations (10, 15 and 20 %) were co-electrospun with PLA fibers and subsequently leached out using distilled water. PLA fibrous membranes without glucose crystals were also produced as controls. The membranes were examined for their morphology, mechanical properties, and potential to support the proliferation of fibroblasts. In addition, the immune response to the membranes was evaluated using monocyte-derived macrophages. The glucose crystals were uniformly distributed in the PLA membranes and their removal created open pores without collapsing the structure. Although a reduced Young's modulus was observed for membranes produced using higher glucose crystal concentrations and larger crystal sizes, the structural integrity remained intact, and the values are still suitable for tissue engineering. In vitro results showed that the scaffolds supported the adhesion and proliferation of fibroblasts and the pores created in the PLAmembranes were large enough for fibroblasts infiltration and colonization of the entire scaffold without inducing an inflammatory response.

Synthesis, Characterization and Application of Advanced Antimicrobial Electrospun Polymers

The aim of this work was to synthesize, characterize and apply advanced antimicrobial biocompatible electrospun polymers suitable for medical implants for surgical repairs. Injuries to the musculoskeletal system often necessitate surgical repair, but current treatments can still lead to high failure rates, such as 40% for the repair of rotator cuff tears. Therefore, there is an urgent need for the development of new biocompatible materials that can effectively support the repair of damaged tissues. Additionally, infections acquired during hospitalization, particularly those caused by antibiotic-resistant bacteria, result in more fatalities than AIDS, tuberculosis, and viral hepatitis combined. This underscores the critical necessity for the advancement of antimicrobial implants with specialized coatings capable of combating Methicillin-resistant Staphylococcus aureus (MRSA) and Methicillin-sensitive Staphylococcus aureus (MSSA), two strains notoriously known for their antibiotic resistance. Therefore, we developed an antimicrobial coating incorporating nanoparticle mixtures using the sol-gel process and applied it to electrospun polycaprolactone (PCL) filaments, followed by thorough characterization by using spectroscopic (FTIR, Raman, NMR) microscopic (SEM and SEM-EDX), and tensile test. The results have shown that the integration of electro-spinning technology for yarn production, coupled with surface modification techniques, holds significant potential for creating antimicrobial materials suitable for medical implants for surgical repairs.

Nanocellulose-based hydrogels as versatile materials with interesting functional properties for tissue engineering applications

Tissue engineering has emerged as a remarkable field aiming to restore or replace damaged tissues through the use of biomimetic constructs. Among the diverse materials investigated for this purpose, nanocellulose-based hydrogels have garnered attention due to their intriguing biocompatibility, tunable mechanical properties, and sustainability. Over the past few years, numerous research works have been published focusing on the successful use of nanocellulose-based hydrogels as artificial extracellular matrices for regenerating various types of tissues. The review emphasizes the importance of tissue engineering, highlighting hydrogels as biomimetic scaffolds, and specifically focuses on the role of nanocellulose in composites that mimic the structures, properties, and functions of the native extracellular matrix for regenerating damaged tissues. It also summarizes the types of nanocellulose, as well as their structural, mechanical, and biological properties, and their contributions to enhancing the properties and characteristics of functional hydrogels for tissue engineering of skin, bone, cartilage, heart, nerves and blood vessels. Additionally, recent advancements in the application of nanocellulose-based hydrogels for tissue engineering have been evaluated and documented. The review also addresses the challenges encountered in their fabrication while exploring the potential future prospects of these hydrogel matrices for biomedical applications.

Decellularized extracellular matrix-decorated 3D nanofiber scaffolds enhance cellular responses and tissue regeneration

The use of decellularized extracellular matrix products in tissue regeneration is quite alluring yet practically challenging due to the limitations of its availability, harsh processing techniques, and host rejection. Scaffolds obtained by either incorporating extracellular matrix (ECM) material or coating the surface can resolve these challenges to some extent. However, these scaffolds lack the complex 3D network formed by proteins and growth factors observed in natural ECM. This study introduces an approach utilizing 3D nanofiber scaffolds decorated with dECM to enhance cellular responses and promote tissue regeneration. Notably, the dECM can be customized according to specific cellular requirements, offering a tailored environment for enhanced therapeutic outcomes. Two types of 3D expanded scaffolds, namely radially aligned scaffolds (RAS) and laterally expanded scaffolds (LES) fabricated by the gas-foaming expansion were utilized. To demonstrate the proof-of-concept, human dermal fibroblasts (HDFs) seeded on these scaffolds for up to 8 weeks, resulted in uniform and highly aligned cells which deposited ECM on the scaffolds. These cellular components were then removed from the scaffolds through decellularization (e.g., SDS treatment and freeze-thaw cycles). The dECM-decorated 3D expanded nanofiber scaffolds can direct and support cell alignment and proliferation along the underlying fibers upon recellularization. An in vitro inflammation assay indicates that dECM-decorated LES induces a lower immune response than dECM-decorated RAS. Further, subcutaneous implantation of dECM-decorated RAS and LES shows higher cell infiltration and angiogenesis within 7 and 14 days than RAS and LES without dECM decoration. Taken together, dECM-decorated 3D expanded nanofiber scaffolds hold great potential in tissue regeneration and tissue modeling. STATEMENT OF SIGNIFICANCE: Decellularized ECM scaffolds have attained widespread attention in biomedical applications due to their intricate 3D framework of proteins and growth factors. Mimicking such a complicated architecture is a clinical challenge. In this study, we developed natural ECM-decorated 3D electrospun nanofiber scaffolds with controlled alignments to mimic human tissue. Fibroblasts were cultured on these scaffolds for 8 weeks to deposit natural ECM and decellularized by either freeze-thawing or detergent to obtain decellularized ECM scaffolds. These scaffolds were tested in both in-vitro and in-vivo conditions. They displayed higher cellular attributes with lower immune response making them a good grafting tool in tissue regeneration.

Effect of nanodiamonds surface deposition on hydrophilicity, bulk degradation andin-vitrocell adhesion of 3D-printed polycaprolactone scaffolds for bone tissue engineering

This study was designed to deposit nanodiamonds (NDs) on 3D-printed poly-ϵ-caprolactone (PCL) scaffolds and evaluate their effect on the surface topography, hydrophilicity, degradation, andin-vitrocell adhesion compared to untreated PCL scaffolds. The PCL scaffold specimens were 3D-printed by fused deposition modeling (FDM) technique with specific porosity parameters. The 3D-printed specimens' surfaces were modified by NDs deposition followed by oxygen plasma post-treatment using a plasma focus device and a non-thermal atmospheric plasma jet, respectively. Specimens were evaluated through morphological characterization by field emission scanning electron microscope (FESEM), microstructure characterization by Raman spectroscopy, chemical characterization by Fourier transform infrared (FTIR) spectroscopy, hydrophilicity degree by contact angle and water uptake measurements, andin-vitrodegradation measurements (n= 6). In addition,in-vitrobone marrow mesenchymal stem cells adhesion was evaluated quantitatively by confocal microscopy and qualitatively by FESEM at different time intervals after cell seeding (n= 6). The statistical significance level was set atp⩽ 0.05. The FESEM micrographs, the Raman, and FTIR spectra confirmed the successful surface deposition of NDs on scaffold specimens. The NDs treated specimens showed nano-scale features distributed homogeneously across the surface compared to the untreated ones. Also, the NDs treated specimens revealed a statistically significant smaller contact angle (17.45 ± 1.34 degrees), higher water uptake percentage after 24 h immersion in phosphate buffer saline (PBS) (21.56% ± 1.73), and higher degradation rate after six months of immersion in PBS (43.92 ± 0.77%). Moreover, enhanced cell adhesion at all different time intervals was observed in NDs treated specimens with higher nuclei area fraction percentage (69.87 ± 3.97%) compared to the untreated specimens (11.46 ± 1.34%). Surface deposition of NDs with oxygen-containing functional groups on 3D-printed PCL scaffolds increased their hydrophilicity and degradation rate with significant enhancement of thein-vitrocell adhesion compared to untreated PCL scaffolds.

A progress update on the biological effects of biodegradable microplastics on soil and ocean environment: A perfect substitute or new threat?

Conventional plastics are inherently difficult to degrade, causing serious plastic pollution. With the development of society, biodegradable plastics (BPs) are considered as an alternative to traditional plastics. However, current research indicated that BPs do not undergo complete degradation in natural environments. Instead, they may convert into biodegradable microplastics (BMPs) at an accelerated rate, thereby posing a significant threat to environment. In this paper, the definition, application, distribution, degradation behaviors, bioaccumulation and biomagnification of BPs were reviewed. And the impacts of BMPs on soil and marine ecosystems, in terms of physicochemical property, nutrient cycling, microorganisms, plants and animals were comprehensively summarized. The effects of combined exposure of BMPs with other pollutants, and the mechanism of ecotoxicity induced by BMPs were also addressed. It was found that BMPs reduced pH, increased DOC content, and disrupted the nitrification of nitrogen cycle in soil ecosystem. The shoot dry weight, pod number and root growth of soil plants, and reproduction and body length of soil animals were inhibited by BMPs. Furthermore, the growth of marine plants, and locomotion, body length and survival of marine animals were suppressed by BMPs. Additionally, the ecotoxicity of combined exposure of BMPs with other pollutants has not been uniformly concluded. Exposure to BMPs induced several types of toxicity, including neurotoxicity, gastrointestinal toxicity, reproductive toxicity, immunotoxicity and genotoxicity. The future calls for heightened attention towards the regulation of the degradation of BPs in the environment, and pursuit of interventions aimed at mitigating their ecotoxicity and potential health risks to human.

Ultrasonic Coating of Poly(D,L-lactic acid)/Poly(lactic-co-glycolic acid) Electrospun Fibers with ZnO Nanoparticles to Increase Angiogenesis in the CAM Assay

Critical-size bone defects necessitate bone void fillers that should be integrated well and be easily vascularized. One viable option is to use a biocompatible synthetic polymer and sonocoat it with zinc oxide (ZnO) nanoparticles (NPs). However, the ideal NP concentration and size must be assessed because a high dose of ZnO NPs may be toxic. Electrospun PDLLA/PLGA scaffolds were produced with different concentrations (0.5 or 1.0 s of sonocoating) and sizes of ZnO NPs (25 nm and 70 nm). They were characterized by SEM, EDX, ICP-OES, and the water contact angle. Vascularization and integration into the surrounding tissue were assessed with the CAM assay in the living chicken embryo. SEM, EDX, and ICP-OES confirmed the presence of ZnO NPs on polymer fibers. Sonocoated ZnO NPs lowered the WCA compared with the control. Smaller NPs were more pro-angiogenic exhibiting a higher vessel density than the larger NPs. At a lower concentration, less but larger vessels were visible in an environment with a lower cell density. Hence, the favored combination of smaller ZnO NPs at a lower concentration sonocoated on PDLLA/PLGA electrospun meshes leads to an advanced state of tissue integration and vascularization, providing a valuable synthetic bone graft to be used in clinics in the future.

Editorial for the Special Issue on Biomaterials, Biodevices and Tissue Engineering

Biomaterials, biodevices, and tissue engineering represent the cutting edge of medical science, promising revolutionary solutions to some of humanity's most pressing health challenges (Figure 1) [...].

Osteogenic differentiation of human mesenchymal stem cells on electroactive substrates

This study investigates the effect of electroactivity and electrical charge distribution on the biological response of human bone marrow stem cells (hBMSCs) cultured in monolayer on flat poly(vinylidene fluoride), PVDF, substrates. Differences in cell behaviour, including proliferation, expression of multipotency markers CD90, CD105 and CD73, and expression of genes characteristic of different mesenchymal lineages, were observed both during expansion in basal medium before reaching confluence and in confluent cultures in osteogenic induction medium. The crystallisation of PVDF in the electrically neutral α-phase or in the electroactive phase β, both unpoled and poled, has been found to have an important influence on the biological response. In addition, the presence of a permanent positive or negative surface electrical charge distribution in phase β substrates has also shown a significant effect on cell behaviour.

Two-Photon-Excited FLIM of NAD(P)H and FAD-Metabolic Activity of Fibroblasts for the Diagnostics of Osteoimplant Survival

Bioinert materials such as the zirconium dioxide and aluminum oxide are widely used in surgery and dentistry due to the absence of cytotoxicity of the materials in relation to the surrounding cells of the body. However, little attention has been paid to the study of metabolic processes occurring at the implant-cell interface. The metabolic activity of mouse 3T3 fibroblasts incubated on yttrium-stabilized zirconium ceramics cured with aluminum oxide (ATZ) and stabilized zirconium ceramics (Y-TZP) was analyzed based on the ratio of the free/bound forms of cofactors NAD(P)H and FAD obtained using two-photon microscopy. The results show that fibroblasts incubated on ceramics demonstrate a shift towards the free form of NAD(P)H, which is observed during the glycolysis process, which, according to our assumptions, is related to the porosity of the surface of ceramic structures. Consequently, despite the high viability and good proliferation of fibroblasts assessed using an MTT test and a scanning electron microscope, the cells are in a state of hypoxia during incubation on ceramic structures. The FLIM results obtained in this work can be used as additional information for scientists who are interested in manufacturing osteoimplants.

Impact of mechanical engineering innovations in biomedical advancements

Abstract

The principal objective of the present paper is to meticulously review the family of biomaterials used in implants. A spectrum of applications of biomaterials in the perspective of prosthesis is also presented. This paper also emphasises on the review of the recent advancements in the field of biomedical implants with respect to mechanical engineering perspective. The latest technologies such as finite element modelling of prosthetic implants, additive manufacturing of implants and certain experimental methods adopted in the field of prosthesis are discussed. Moreover, various models were modelled using SOLIDWORKS® 2022 modelling software and analysed using ANSYS® 2021 R2 finite element analysing software and implant models were additive manufactured to make this review more interesting and for better understanding. Overall, the latest technology in the field of mechanical engineering that fuels its impact in life-saving biomedical engineering has been discussed briefly.

Graphical abstract

Chitosan-Based Biomaterial in Wound Healing: A Review

Wound healing is an evolving and intricate technique that is vital to the restoration of tissue integrity and function. Over the past few decades, chitosan a biopolymer derived from chitin, became known as an emerging biomaterial in the field of healing wounds due to its distinctive characteristics including biocompatibility, biodegradability, affinity to biomolecules, and wound-healing activity. This natural polymer exhibits excellent healing capabilities by accelerating the development of new skin cells, reducing inflammation, and preventing infections. Due to its distinct biochemical characteristics and innate antibacterial activity, chitosan has been extensively researched as an antibacterial wound dressing. Chronic wounds, such as diabetic ulcers and liver disease, are a growing medical problem. Chitosan-based biomaterials are a promising solution in the domain of wound care. The article analyzes the depth of chitosan-based biomaterials and their impact on wound healing and also the methods to enhance the advantages of chitosan by incorporating bioactive compounds. This literature review is aimed to improve the understanding and knowledge about biomaterials and their use in wound healing.

Crosslinked Collagen-Hyaluronic Acid Scaffold Enhances Interleukin-10 Under Co-Culture of Macrophages And Adipose-Derived Stem Cells

The skin, the human body's largest organ, possesses a protective barrier that renders it susceptible to various injuries, including burns. Following burn trauma, the inflammatory process triggers both innate and adaptive immune responses, leading to the polarization of macrophages into two distinct phenotypes: the pro-inflammatory M1 and the anti-inflammatory M2. This dual response sets the stage for wound healing and subsequent tissue regeneration. Contributing to this transition from M1 to M2 polarization are human adipose-derived stem cells (ASCs), which employ paracrine signaling and inflammation suppression to enhance the remodeling phase. ASCs, when combined with biocompatible polymers, can be integrated into functional scaffolds. This study introduces an 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide-crosslinked (EDC-crosslinked) collagen-hyaluronic acid (Col-HA) scaffold assembled with ASCs, designed as a natural biomaterial device to modulate macrophage behavior in vitro under co-culture conditions. This innovation aims to improve wound healing processes. The EDC-crosslinked Col-HA scaffold favored the release of anti-inflammatory cytokines by ASCs, which indicated the M2 prevalence. In tissue engineering, a critical objective lies in the development of functional biomaterials capable of guiding specific tissue responses, notably the control of inflammatory processes. Thus, this research not only presents original findings but also points toward a promising avenue within regenerative medicine.

3D bioprinting technology to construct bone reconstruction research model and its feasibility evaluation

Objective: To explore and construct a 3D bone remodeling research model displaying stability, repeatability, and precise simulation of the physiological and biochemical environment in vivo. Methods: In this study, 3D bioprinting was used to construct a bone reconstruction model. Sodium alginate (SA), hydroxyapatite (HA) and gelatin (Gel) were mixed into hydrogel as scaffold material. The osteoblast precursor cells MC3T3-E1 and osteoclast precursor cells RAW264.7 were used as seed cells, which may or may not be separated by polycarbonate membrane. The cytokines osteoprotegerin (OPG) and receptor activator of NF-κB ligand (RANKL) were used to induce cell differentiation. The function of scaffolds in the process of bone remodeling was analyzed by detecting the related markers of osteoblasts (alkaline phosphatase, ALP) and osteoclasts (tartrate resistant acid phosphatase, TRAP). Results: The scaffold showed good biocompatibility and low toxicity. The surface morphology aided cell adhesion and growth. The scaffold had optimum degradability, water absorption capacity and porosity, which are in line with the conditions of biological experiments. The effect of induced differentiation of cells was the best when cultured alone. After direct contact between the two types of cells at 2D or 3D level, the induced differentiation of cells was inhibited to varying degrees, although they still showed osteogenesis and osteoclast. After the cells were induced by indirect contact culture, the effect of induced differentiation improved when compared with direct contact culture, although it was still not as good as that of single culture. On the whole, the effect of inducing differentiation at 3D level was the same as that at 2D level, and its relative gene expression and enzyme activity were higher than that in the control group. Hence the scaffold used in this study could induce osteogenesis as well as osteoclast, thereby rendering it more effective in inducing new bone formation. Conclusion: This method can be used to construct the model of 3D bone remodeling mechanism.

Cross-Linked Alginate Dialdehyde/Chitosan Hydrogel Encompassing Curcumin-Loaded Bilosomes for Enhanced Wound Healing Activity

The current study aimed to fabricate curcumin-loaded bilosomal hydrogel for topical wound healing purposes, hence alleviating the poor aqueous solubility and low oral bioavailability of curcumin. Bilosomes were fabricated via the thin film hydration technique using cholesterol, Span® 60, and two different types of bile salts (sodium deoxycholate or sodium cholate). Bilosomes were verified for their particle size (PS), polydispersity index (PDI), zeta potential (ZP), entrapment efficiency (EE%), and in vitro drug release besides their morphological features. The optimum formulation was composed of cholesterol/Span® 60 (molar ratio 1:10 w/w) and 5 mg of sodium deoxycholate. This optimum formulation was composed of a PS of 246.25 ± 11.85 nm, PDI of 0.339 ± 0.030, ZP of -36.75 ± 0.14 mv, EE% of 93.32% ± 0.40, and the highest percent of drug released over three days (96.23% ± 0.02). The optimum bilosomal formulation was loaded into alginate dialdehyde/chitosan hydrogel cross-linked with calcium chloride. The loaded hydrogel was tested for its water uptake capacity, in vitro drug release, and in vivo studies on male Albino rats. The results showed that the loaded hydrogel possessed a high-water uptake percent at the four-week time point (729.50% ± 43.13) before it started to disintegrate gradually; in addition, it showed sustained drug release for five days (≈100%). In vivo animal testing and histopathological studies supported the superiority of the curcumin-loaded bilosomal hydrogel in wound healing compared to the curcumin dispersion and plain hydrogel, where there was a complete wound closure attained after the three-week period with a proper healing mechanism. Finally, it was concluded that curcumin-loaded bilosomal hydrogel offered a robust, efficient, and user-friendly dosage form for wound healing.

Surface Modification Progress for PLGA-Based Cell Scaffolds

Poly(lactic-glycolic acid) (PLGA) is a biocompatible bio-scaffold material, but its own hydrophobic and electrically neutral surface limits its application as a cell scaffold. Polymer materials, mimics ECM materials, and organic material have often been used as coating materials for PLGA cell scaffolds to improve the poor cell adhesion of PLGA and enhance tissue adaptation. These coating materials can be modified on the PLGA surface via simple physical or chemical methods, and coating multiple materials can simultaneously confer different functions to the PLGA scaffold; not only does this ensure stronger cell adhesion but it also modulates cell behavior and function. This approach to coating could facilitate the production of more PLGA-based cell scaffolds. This review focuses on the PLGA surface-modified materials, methods, and applications, and will provide guidance for PLGA surface modification.

Effectiveness of a polycaprolactone scaffold combined with platelet-rich fibrin as guided tissue regeneration materials for preserving an implant-supported overdenture

Objectives

This study aimed to assess the effectiveness of ridge preservation using a polycaprolactone (PCL) scaffold combined with platelet-rich fibrin (PRF) to promote bone regeneration before implantation.

Materials and Methods

This prospective study was conducted at Al-Azhar University in Egypt. It included 30 participants requiring the extraction of their last mandibular premolar before constructing an implant-supported overdenture. The participants were divided into three groups: Group A was treated with a PCL scaffold and PRF as ridge preservative materials, Group B was treated with PRF alone, and Group C (control) was treated with no preservative material. Bone samples were collected for histomorphometric analysis at implant placement.

Results

The participants' mean age was 65.3 ± 4.27 years, and 18 (60%) were male. Postoperative alveolar bone lengths differed significantly between Groups A and B (P = 0.001). However, alveolar bone width changes did not differ significantly among groups. In contrast, the postoperative bone density and loss differed significantly among groups (P = 0.001).

Conclusion

Combining two ridge preservation techniques (PCL and PRF) enhanced participants' alveolar bone remodelling by decreasing its resorption and maintaining its width.

Thermoresponsive Alginate-Graft-pNIPAM/Methyl Cellulose 3D-Printed Scaffolds Promote Osteogenesis In Vitro

In this work, a sodium alginate-based copolymer grafted by thermoresponsive poly(N-isopropylacrylamide) (PNIPAM) chains was used as gelator (Alg-g-PNIPAM) in combination with methylcellulose (MC). It was found that the mechanical properties of the resulting gel could be enhanced by the addition of MC and calcium ions (Ca2+). The proposed network is formed via a dual crosslinking mechanism including ionic interactions among Ca2+ and carboxyl groups and secondary hydrophobic associations of PNIPAM chains. MC was found to further reinforce the dynamic moduli of the resulting gels (i.e., a storage modulus of ca. 1500 Pa at physiological body and post-printing temperature), rendering them suitable for 3D printing in biomedical applications. The polymer networks were stable and retained their printed fidelity with minimum erosion as low as 6% for up to seven days. Furthermore, adhered pre-osteoblastic cells on Alg-g-PNIPAM/MC printed scaffolds presented 80% viability compared to tissue culture polystyrene control, and more importantly, they promoted the osteogenic potential, as indicated by the increased alkaline phosphatase activity, calcium, and collagen production relative to the Alg-g-PNIPAM control scaffolds. Specifically, ALP activity and collagen secreted by cells were significantly enhanced in Alg-g-PNIPAM/MC scaffolds compared to the Alg-g-PNIPAM counterparts, demonstrating their potential in bone tissue engineering.

Cellulosic Textiles-An Appealing Trend for Different Pharmaceutical Applications

Cellulose, the most abundant biopolymer in nature, is derived from various sources. The production of pharmaceutical textiles based on cellulose represents a growing sector. In medicated textiles, textile and pharmaceutical sciences are integrated to develop new healthcare approaches aiming to improve patient compliance. Through the possibility of cellulose functionalization, pharmaceutical textiles can broaden the applications of cellulose in the biomedical field. This narrative review aims to illustrate both the methods of extraction and preparation of cellulose fibers, with a particular focus on nanocellulose, and diverse pharmaceutical applications like tissue restoration and antimicrobial, antiviral, and wound healing applications. Additionally, the merging between fabricated cellulosic textiles with drugs, metal nanoparticles, and plant-derived and synthetic materials are also illustrated. Moreover, new emerging technologies and the use of smart medicated textiles (3D and 4D cellulosic textiles) are not far from those within the review scope. In each section, the review outlines some of the limitations in the use of cellulose textiles, indicating scientific research that provides significant contributions to overcome them. This review also points out the faced challenges and possible solutions in a trial to present an overview on all issues related to the use of cellulose for the production of pharmaceutical textiles.

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.

Bio-Based PLA/PBS/PBAT Ternary Blends with Added Nanohydroxyapatite: A Thermal, Physical, and Mechanical Study

The physical and mechanical properties of novel bio-based polymer blends of polylactic acid (PLA), poly(butylene succinate) (PBS), and poly (butylene adipate-co-terephthalate) (PBAT) with various added amounts of nanohydroxyapatite (nHA) were investigated in this study. The formulations of PLA/PBS/PBAT/nHA blends were divided into two series, A and B, containing 70 or 80 wt% PLA, respectively. Samples of four specimens per series were prepared using a twin-screw extruder, and different amounts of nHA were added to meet the regeneration needs of bone graft materials. FTIR and XRD analyses were employed to identify the presence of each polymer and nHA in the various blends. The crystallization behavior of these blends was examined using DSC. Tensile and impact strength tests were performed on all samples to screen feasible formulations of polymer blends for bone graft material applications. Surface morphology analyses were conducted using SEM, and the dispersion of nHA particles in the blends was further tested using TEM. The added nHA also served as a nucleating agent aimed at improving the crystallinity and mechanical properties of the blends. Through the above analyses, the physical and mechanical properties of the polymer blends are reported and the most promising bone graft material formulations are suggested. All blends were tested for thermal degradation analysis using TGA and thermal stability was confirmed. The water absorption experiments carried out in this study showed that the addition of nHA could improve the hydrophilicity of the blends.

Three-Dimensional Bioprinting in Soft Tissue Engineering for Plastic and Reconstructive Surgery

Skeletal muscle tissue engineering (TE) and adipose tissue engineering have undergone significant progress in recent years. This review focuses on the key findings in these areas, particularly highlighting the integration of 3D bioprinting techniques to overcome challenges and enhance tissue regeneration. In skeletal muscle TE, 3D bioprinting enables the precise replication of muscle architecture. This addresses the need for the parallel alignment of cells and proper innervation. Satellite cells (SCs) and mesenchymal stem cells (MSCs) have been utilized, along with co-cultivation strategies for vascularization and innervation. Therefore, various printing methods and materials, including decellularized extracellular matrix (dECM), have been explored. Similarly, in adipose tissue engineering, 3D bioprinting has been employed to overcome the challenge of vascularization; addressing this challenge is vital for graft survival. Decellularized adipose tissue and biomimetic scaffolds have been used as biological inks, along with adipose-derived stem cells (ADSCs), to enhance graft survival. The integration of dECM and alginate bioinks has demonstrated improved adipocyte maturation and differentiation. These findings highlight the potential of 3D bioprinting techniques in skeletal muscle and adipose tissue engineering. By integrating specific cell types, biomaterials, and printing methods, significant progress has been made in tissue regeneration. However, challenges such as fabricating larger constructs, translating findings to human models, and obtaining regulatory approvals for cellular therapies remain to be addressed. Nonetheless, these advancements underscore the transformative impact of 3D bioprinting in tissue engineering research and its potential for future clinical applications.

Development and Characterization of Electrospun Composites Built on Polycaprolactone and Cerium-Containing Phases

The current study reports on the fabrication of composite scaffolds based on polycaprolactone (PCL) and cerium (Ce)-containing powders, followed by their characterization from compositional, structural, morphological, optical and biological points of view. First, CeO2, Ce-doped calcium phosphates and Ce-substituted bioglass were synthesized by wet-chemistry methods (precipitation/coprecipitation and sol-gel) and subsequently loaded on PCL fibres processed by electrospinning. The powders were proven to be nanometric or micrometric, while the investigation of their phase composition showed that Ce was present as a dopant within the crystal lattice of the obtained calcium phosphates or as crystalline domains inside the glassy matrix. The best bioactivity was attained in the case of Ce-containing bioglass, while the most pronounced antibacterial effect was visible for Ce-doped calcium phosphates calcined at a lower temperature. The scaffolds were composed of either dimensionally homogeneous fibres or mixtures of fibres with a wide size distribution and beads of different shapes. In most cases, the increase in polymer concentration in the precursor solution ensured the achievement of more ordered fibre mats. The immersion in SBF for 28 days triggered an incipient degradation of PCL, evidenced mostly through cracks and gaps. In terms of biological properties, the composite scaffolds displayed a very good biocompatibility when tested with human osteoblast cells, with a superior response for the samples consisting of the polymer and Ce-doped calcium phosphates.

The Recent Applications of PLGA-Based Nanostructures for Ischemic Stroke

With the accelerated development of nanotechnology in recent years, nanomaterials have become increasingly prevalent in the medical field. The poly (lactic acid-glycolic acid) copolymer (PLGA) is one of the most commonly used biodegradable polymers. It is biocompatible and can be fabricated into various nanostructures, depending on requirements. Ischemic stroke is a common, disabling, and fatal illness that burdens society. There is a need for further improvement in the diagnosis and treatment of this disease. PLGA-based nanostructures can facilitate therapeutic compounds' passage through the physicochemical barrier. They further provide both sustained and controlled release of therapeutic compounds when loaded with drugs for the treatment of ischemic stroke. The clinical significance and potential of PLGA-based nanostructures can also be seen in their applications in cell transplantation and imaging diagnostics of ischemic stroke. This paper summarizes the synthesis and properties of PLGA and reviews in detail the recent applications of PLGA-based nanostructures for drug delivery, disease therapy, cell transplantation, and the imaging diagnosis of ischemic stroke.

Promising Novel Therapies in the Treatment of Aortic and Visceral Aneurysms

Aortic and visceral aneurysms affect large arterial vessels, including the thoracic and abdominal aorta, as well as visceral arterial branches, such as the splenic, hepatic, and mesenteric arteries, respectively. Although these clinical entities have not been equally researched, it seems that they might share certain common pathophysiological changes and molecular mechanisms. The yet limited published data, with regard to newly designed, novel therapies, could serve as a nidus for the evaluation and potential implementation of such treatments in large artery aneurysms. In both animal models and clinical trials, various novel treatments have been employed in an attempt to not only reduce the complications of the already implemented modalities, through manufacturing of more durable materials, but also to regenerate or replace affected tissues themselves. Cellular populations like stem and differentiated vascular cell types, large diameter tissue-engineered vascular grafts (TEVGs), and various molecules and biological factors that might target aspects of the pathophysiological process, including cell-adhesion stabilizers, metalloproteinase inhibitors, and miRNAs, could potentially contribute significantly to the treatment of these types of aneurysms. In this narrative review, we sought to collect and present relevant evidence in the literature, in an effort to unveil promising biological therapies, possibly applicable to the treatment of aortic aneurysms, both thoracic and abdominal, as well as visceral aneurysms.

CAM Model: Intriguing Natural Bioreactor for Sustainable Research and Reliable/Versatile Testing

We are witnessing the revival of the CAM model, which has already used been in the past by several researchers studying angiogenesis and anti-cancer drugs and now offers a refined model to fill, in the translational meaning, the gap between in vitro and in vivo studies. It can be used for a wide range of purposes, from testing cytotoxicity, pharmacokinetics, tumorigenesis, and invasion to the action mechanisms of molecules and validation of new materials from tissue engineering research. The CAM model is easy to use, with a fast outcome, and makes experimental research more sustainable since it allows us to replace, reduce, and refine pre-clinical experimentation ("3Rs" rules). This review aims to highlight some unique potential that the CAM-assay presents; in particular, the authors intend to use the CAM model in the future to verify, in a microenvironment comparable to in vivo conditions, albeit simplified, the angiogenic ability of functionalized 3D constructs to be used in regenerative medicine strategies in the recovery of skeletal injuries of critical size (CSD) that do not repair spontaneously. For this purpose, organotypic cultures will be planned on several CAMs set up in temporal sequences, and a sort of organ model for assessing CSD will be utilized in the CAM bioreactor rather than in vivo.

Topology Optimization of a Femoral Stem in Titanium and Carbon to Reduce Stress Shielding with the FEM Method

Arthroplasty is commonly performed to treat advanced osteoarthritis or other degenerative joint conditions; however, it can also be considered for young patients with severe joint damage that significantly limits their functionality and quality of life. Young patients are still at risk of aseptic mobilization and bone resorption due to the phenomenon of stress shielding that causes an uneven distribution of tensions along the femoral contact surface prosthesis. This phenomenon can be limited by choosing the material of the prosthesis appropriately or by varying its stiffness, making sure that its mechanical behavior simulates that of the femur as much as possible. The aim of this study is to evaluate the mechanical strength of a prosthesis optimized both in shape and material and compare the results with a standard titanium prosthesis. Methods: Through three-dimensional modeling and the use of finite element method (FEM) software such as ANSYS, the mechanical behavior of traditional prosthesis and prosthesis optimized topologically respecting the ASTM F2996-13 standard. Results: With topological optimization, there is a stress reduction from 987 MPa to 810 MPa with a mass reduction of 30%. When carbon fiber is used, it is possible to further reduce stress to 509 MPa. Conclusions: The reduction in stress on the femoral stem allows an optimal distribution of the load on the cortical bone, thus decreasing the problem of stress shielding.

Poly(3-hydroxybutyrate) 3D-Scaffold-Conduit for Guided Tissue Sprouting

Scaffold biocompatibility remains an urgent problem in tissue engineering. An especially interesting problem is guided cell intergrowth and tissue sprouting using a porous scaffold with a special design. Two types of structures were obtained from poly(3-hydroxybutyrate) (PHB) using a salt leaching technique. In flat scaffolds (scaffold-1), one side was more porous (pore size 100-300 μm), while the other side was smoother (pore size 10-50 μm). Such scaffolds are suitable for the in vitro cultivation of rat mesenchymal stem cells and 3T3 fibroblasts, and, upon subcutaneous implantation to older rats, they cause moderate inflammation and the formation of a fibrous capsule. Scaffold-2s are homogeneous volumetric hard sponges (pore size 30-300 μm) with more structured pores. They were suitable for the in vitro culturing of 3T3 fibroblasts. Scaffold-2s were used to manufacture a conduit from the PHB/PHBV tube with scaffold-2 as a filler. The subcutaneous implantation of such conduits to older rats resulted in gradual soft connective tissue sprouting through the filler material of the scaffold-2 without any visible inflammatory processes. Thus, scaffold-2 can be used as a guide for connective tissue sprouting. The obtained data are advanced studies for reconstructive surgery and tissue engineering application for the elderly patients.

Combinational System of Lipid-Based Nanocarriers and Biodegradable Polymers for Wound Healing: An Updated Review

Skin wounds have imposed serious socioeconomic burdens on healthcare providers and patients. There are just more than 25,000 burn injury-related deaths reported each year. Conventional treatments do not often allow the re-establishment of the function of affected regions and structures, resulting in dehydration and wound infections. Many nanocarriers, such as lipid-based systems or biobased and biodegradable polymers and their associated platforms, are favorable in wound healing due to their ability to promote cell adhesion and migration, thus improving wound healing and reducing scarring. Hence, many researchers have focused on developing new wound dressings based on such compounds with desirable effects. However, when applied in wound healing, some problems occur, such as the high cost of public health, novel treatments emphasizing reduced healthcare costs, and increasing quality of treatment outcomes. The integrated hybrid systems of lipid-based nanocarriers (LNCs) and polymer-based systems can be promising as the solution for the above problems in the wound healing process. Furthermore, novel drug delivery systems showed more effective release of therapeutic agents, suitable mimicking of the physiological environment, and improvement in the function of the single system. This review highlights recent advances in lipid-based systems and the role of lipid-based carriers and biodegradable polymers in wound healing.

Silk-Based Biomaterials for Designing Bioinspired Microarchitecture for Various Biomedical Applications

Biomaterial research has led to revolutionary healthcare advances. Natural biological macromolecules can impact high-performance, multipurpose materials. This has prompted the quest for affordable healthcare solutions, with a focus on renewable biomaterials with a wide variety of applications and ecologically friendly techniques. Imitating their chemical compositions and hierarchical structures, bioinspired based materials have elevated rapidly over the past few decades. Bio-inspired strategies entail extracting fundamental components and reassembling them into programmable biomaterials. This method may improve its processability and modifiability, allowing it to meet the biological application criteria. Silk is a desirable biosourced raw material due to its high mechanical properties, flexibility, bioactive component sequestration, controlled biodegradability, remarkable biocompatibility, and inexpensiveness. Silk regulates temporo-spatial, biochemical and biophysical reactions. Extracellular biophysical factors regulate cellular destiny dynamically. This review examines the bioinspired structural and functional properties of silk material based scaffolds. We explored silk types, chemical composition, architecture, mechanical properties, topography, and 3D geometry to unlock the body's innate regenerative potential, keeping in mind the novel biophysical properties of silk in film, fiber, and other potential forms, coupled with facile chemical changes, and its ability to match functional requirements for specific tissues.

Development of Strong and Tough β-TCP/PCL Composite Scaffolds with Interconnected Porosity by Digital Light Processing and Partial Infiltration

Strong and tough β-TCP/PCL composite scaffolds with interconnected porosity were developed by combining digital light processing and vacuum infiltration. The composite scaffolds were comprised of pure β-TCP, β-TCP matrix composite and PCL matrix composite. The porous β-TCP/PCL composite scaffolds showed remarkable mechanical advantages compared with ceramic scaffolds with the same macroscopic pore structure (dense scaffolds). The composite scaffolds exhibited a significant increase in strain energy density and fracture energy density, though with similar compressive and flexural strengths. Moreover, the composite scaffolds had a much higher Weibull modulus and longer fatigue life than the dense scaffolds. It was revealed that the composite scaffolds with interconnected porosity possess comprehensive mechanical properties (high strength, excellent toughness, significant reliability and fatigue resistance), which suggests that they could replace the pure ceramic scaffolds for degradable bone substitutes, especially in complex stress environments.

Different Curcumin-Loaded Delivery Systems for Wound Healing Applications: A Comprehensive Review

Curcumin or turmeric is the active constituent of Curcuma longa L. It has marvelous medicinal applications in many diseases. When the skin integrity is compromised due to either acute or chronic wounds, the body initiates several steps leading to tissue healing and skin barrier function restoration. Curcumin has very strong antibacterial and antifungal activities with powerful wound healing ability owing to its antioxidant activity. Nevertheless, its poor oral bioavailability, low water solubility and rapid metabolism limit its medical use. Tailoring suitable drug delivery systems for carrying curcumin improves its pharmaceutical and pharmacological effects. This review summarizes the most recent reported curcumin-loaded delivery systems for wound healing purposes, chiefly hydrogels, films, wafers, and sponges. In addition, curcumin nanoformulations such as nanohydrogels, nanoparticles and nanofibers are also presented, which offer better solubility, bioavailability, and sustained release to augment curcumin wound healing effects through stimulating the different healing phases by the aid of the small carrier.

Tissue Engineering for Gastrointestinal and Genitourinary Tracts

The gastrointestinal and genitourinary tracts share several similarities. Primarily, these tissues are composed of hollow structures lined by an epithelium through which materials need to flow with the help of peristalsis brought by muscle contraction. In the case of the gastrointestinal tract, solid or liquid food must circulate to be digested and absorbed and the waste products eliminated. In the case of the urinary tract, the urine produced by the kidneys must flow to the bladder, where it is stored until its elimination from the body. Finally, in the case of the vagina, it must allow the evacuation of blood during menstruation, accommodate the male sexual organ during coitus, and is the natural way to birth a child. The present review describes the anatomy, pathologies, and treatments of such organs, emphasizing tissue engineering strategies.