A Comparative Review of Natural and Synthetic Biopolymer Composite Scaffolds

Biopolymer-based solutions for enhanced safety and quality assurance: A review

The improper disposal of petroleum-based plastics has been associated with detrimental environmental consequences, such as the proliferation of microplastic pollution and increased emissions of greenhouse gases (GHGs). Consequently, biopolymers have emerged as a highly regarded alternative due to their environmental-friendly attributes and versatile range of applications. In response to consumer demands for safer food options, sustainable packaging, and escalating environmental concerns, the food sector is increasingly adopting biopolymers. Further, in the recent decade, the usage of active or functional biopolymers has evolved into smart biopolymers that can transmit real-time data to consumers. This review covers key topics such as antimicrobial and biodegradable packaging, edible coatings and films, incorporation of scavengers and bioactive substances that prolong the shelf life and guard against moisture and microbial contamination. The paper also discusses the development of edible cutlery as a sustainable substitute for plastic, the encapsulation of bioactive substances within biopolymers, 3-D food printing for regulated nutrition delivery and thickening and gelling agents that improve food texture and stability. It also discusses the integration of smart polymer functions, demonstrating their importance in guaranteeing food safety and quality, such as biosensing, pH and gas detection, antibacterial characteristics, and time-temperature monitoring. By shedding light on market trends, future scope, and potentialities, this review aims to elucidate the prospects of utilizing biopolymers to address sustainability and quality concerns within the food industry effectively.

Scaffolding fundamentals and recent advances in sustainable scaffolding techniques for cultured meat development

In cultured meat (CM) production, Scaffolding plays an important role by aiding cell adhesion, growth, differentiation, and alignment. The existence of fibrous microstructure in connective and muscle tissues has attracted considerable interest in the realm of tissue engineering and triggered the interest of researchers to implement scaffolding techniques. A wide array of research efforts is ongoing in scaffolding technologies for achieving the real meat structure on the principality of biomedical research and to replace serum free CM production. Scaffolds made of animal-derived biomaterials are found efficient in replicating the extracellular matrix (ECM), thus focus should be paid to utilize animal byproducts for this purpose. Proper identification and utilization of plant-derived scaffolding biomaterial could be helpful to add diversified options in addition to animal derived sources and reduce in cost of CM production through scaffolds. Furthermore, techniques like electrospinning, modified electrospinning and 3D bioprinting should be focused on to create 3D porous scaffolds to mimic the ECM of the muscle tissue and form real meat-like structures. This review discusses recent advances in cutting edge scaffolding techniques and edible biomaterials related to structured CM production.

Engineering cell-derived extracellular matrix for peripheral nerve regeneration

Extracellular matrices (ECMs) play a key role in nerve repair and are recognized as the natural source of biomaterials. In parallel to extensively studied tissue-derived ECMs (ts-ECMs), cell-derived ECMs (cd-ECMs) also have the capability to partially recapitulate the complicated regenerative microenvironment of native nerve tissues. Notably, cd-ECMs can avoid the shortcomings of ts-ECMs. Cd-ECMs can be prepared by culturing various cells or even autologous cells in vitro under pathogen-free conditions. And mild decellularization can achieve efficient removal of immunogenic components in cd-ECMs. Moreover, cd-ECMs are more readily customizable to achieve the desired functional properties. These advantages have garnered significant attention for the potential of cd-ECMs in neuroregenerative medicine. As promising biomaterials, cd-ECMs bring new hope for the effective treatment of peripheral nerve injuries. Herein, this review comprehensively examines current knowledge about the functional characteristics of cd-ECMs and their mechanisms of interaction with cells in nerve regeneration, with a particular focus on the preparation, engineering optimization, and scalability of cd-ECMs. The applications of cd-ECMs from distinct cell sources reported in peripheral nerve tissue engineering are highlighted and summarized. Furthermore, current limitations that should be addressed and outlooks related to clinical translation are put forward as well.

SonoPrint: Acoustically Assisted Volumetric 3D Printing for Composites

Advances in additive manufacturing in composites have transformed aerospace, medical devices, tissue engineering, and electronics. A key aspect of enhancing properties of 3D-printed objects involves fine-tuning the material by embedding and orienting reinforcement within the structure. Existing methods for orienting these reinforcements are limited by pattern types, alignment, and particle characteristics. Acoustics offers a versatile method to control the particles independent of their size, geometry, and charge, enabling intricate pattern formations. However, integrating acoustics into 3D printing has been challenging due to the scattering of the acoustic field between polymerized layers and unpolymerized resin, resulting in unwanted patterns. To address this challenge, SonoPrint, an innovative acoustically assisted volumetric 3D printer is developed that enables simultaneous reinforcement patterning and printing of the entire structure. SonoPrint generates mechanically tunable composite geometries by embedding reinforcement particles, such as microscopic glass, metal, and polystyrene, within the fabricated structure. This printer employs a standing wave field to create targeted particle motifs-including parallel lines, radial lines, circles, rhombuses, hexagons, and polygons-directly in the photosensitive resin, completing the print in just a few minutes. SonoPrint enhances structural properties and promises to advance volumetric printing, unlocking applications in tissue engineering, biohybrid robots, and composite fabrication.

Global trends in clinical trials involving engineered biomaterials

Engineered biomaterials are materials specifically designed to interact with biological systems for biomedical applications. This paper offers the comprehensive analysis of global clinical trial trends involving such materials. We surveyed 834 studies in the ClinicalTrials.gov database and explored biomaterial types, their initiation points, and durations in clinical trials. Predominantly, synthetic and natural polymers, particularly silicone and collagen, are used. Trials, focusing on ophthalmology, dentistry, and vascular medicine, are primarily conducted in the United States, Canada, and Italy. These trials encompass a broad demographic, and trials enrolled fewer than 100 participants. The study duration varied ranging from 0.5 to 4.5 years. These biomaterials are mainly bioresorbable or bioinert, with the integration of cells in biomaterials remaining an underexplored area. Our findings shed light on current practices and future potentials of engineered biomaterials in clinical research, offering insights for advancing this dynamic field globally.

Challenges and Opportunities in Developing Tracheal Substitutes for the Recovery of Long-Segment Defects

Tracheal resection and reconstruction procedures are necessary when stenosis, tracheomalacia, tumors, vascular lesions, or tracheal injury cause a tracheal blockage. Replacement with a tracheal substitute is often recommended when the trauma exceeds 50% of the total length of the trachea in adults and 30% in children. Recently, tissue engineering and other advanced techniques have shown promise in fabricating biocompatible tracheal substitutes with physical, morphological, biomechanical, and biological characteristics similar to native trachea. Different polymers and biometals are explored. Even with limited success with tissue-engineered grafts in clinical settings, complete healing of tracheal defects remains a substantial challenge due to low mechanical strength and durability of the graft materials, inadequate re-epithelialization and vascularization, and restenosis. This review has covered a range of reconstructive and regenerative techniques, design criteria, the use of bioprostheses and synthetic grafts for the recovery of tracheal defects, as well as the traditional and cutting-edge methods of their fabrication, surface modification for increased immuno- or biocompatibility, and associated challenges.

Amniotic Membrane-Derived Multichannel Hydrogels for Neural Tissue Repair

In the pursuit of advancing neural tissue regeneration, biomaterial scaffolds have emerged as promising candidates, offering potential solutions for nerve disruptions. Among these scaffolds, multichannel hydrogels, characterized by meticulously designed micrometer-scale channels, stand out as instrumental tools for guiding axonal growth and facilitating cellular interactions. This study explores the innovative application of human amniotic membranes modified with methacryloyl domains (AMMA) in neural stem cell (NSC) culture. AMMA hydrogels, possessing a tailored softness resembling the physiological environment, are prepared in the format of multichannel scaffolds to simulate native-like microarchitecture of nerve tracts. Preliminary experiments on AMMA hydrogel films showcase their potential for neural applications, demonstrating robust adhesion, proliferation, and differentiation of NSCs without the need for additional coatings. Transitioning into the 3D realm, the multichannel architecture fosters intricate neuronal networks guiding neurite extension longitudinally. Furthermore, the presence of synaptic vesicles within the cellular arrays suggests the establishment of functional synaptic connections, underscoring the physiological relevance of the developed neuronal networks. This work contributes to the ongoing efforts to find ethical, clinically translatable, and functionally relevant approaches for regenerative neuroscience.

Navigating the challenges and exploring the perspectives associated with emerging novel biomaterials

The field of biomaterials is a continuously evolving interdisciplinary field encompassing biological sciences, materials sciences, chemical sciences, and physical sciences with a multitude of applications realized every year. However, different biomaterials developed for different applications have unique challenges in the form of biological barriers, and addressing these challenges simultaneously is also a challenge. Nevertheless, immense progress has been made through the development of novel materials with minimal adverse effects such as DNA nanostructures, specific synthesis strategies based on supramolecular chemistry, and modulating the shortcomings of existing biomaterials through effective functionalization techniques. This review discusses all these aspects of biomaterials, including the challenges at each level of their development and application, proposed countermeasures for these challenges, and some future directions that may have potential benefits.

Mechanobiological Modulation of In Vitro Astrocyte Reactivity Using Variable Gel Stiffness

After traumatic brain injury, the brain extracellular matrix undergoes structural rearrangement due to changes in matrix composition, activation of proteases, and deposition of chondroitin sulfate proteoglycans by reactive astrocytes to produce the glial scar. These changes lead to a softening of the tissue, where the stiffness of the contusion "core" and peripheral "pericontusional" regions becomes softer than that of healthy tissue. Pioneering mechanotransduction studies have shown that soft substrates upregulate intermediate filament proteins in reactive astrocytes; however, many other aspects of astrocyte biology remain unclear. Here, we developed a platform for the culture of cortical astrocytes using polyacrylamide (PA) gels of varying stiffness (measured in Pascal; Pa) to mimic injury-related regions in order to investigate the effects of tissue stiffness on astrocyte reactivity and morphology. Our results show that substrate stiffness influences astrocyte phenotype; soft 300 Pa substrates led to increased GFAP immunoreactivity, proliferation, and complexity of processes. Intermediate 800 Pa substrates increased Aggrecan+, Brevican+, and Neurocan+ astrocytes. The stiffest 1 kPa substrates led to astrocytes with basal morphologies, similar to a physiological state. These results advance our understanding of astrocyte mechanotransduction processes and provide evidence of how substrates with engineered stiffness can mimic the injury microenvironment.

Application and Development of Electrospun Nanofiber Scaffolds for Bone Tissue Engineering

Nanofiber scaffolds have gained significant attention in the field of bone tissue engineering. Electrospinning, a straightforward and efficient technique for producing nanofibers, has been extensively researched. When used in bone tissue engineering scaffolds, electrospun nanofibers with suitable surface properties promote new bone tissue growth and enhance cell adhesion. Recent advancements in electrospinning technology have provided innovative approaches for scaffold fabrication in bone tissue engineering. This review comprehensively examines the utilization of electrospun nanofibers in bone tissue engineering scaffolds and evaluates the relevant literature. The review begins by presenting the fundamental principles and methodologies of electrospinning. It then discusses various materials used in the production of electrospun nanofiber scaffolds for bone tissue engineering, including natural and synthetic polymers, as well as certain inorganic materials. The challenges associated with these materials are also described. The review focuses on novel electrospinning techniques for scaffold construction in bone tissue engineering, such as multilayer nanofibers, multifluid electrospinning, and the integration of electrospinning with other methods. Recent advancements in electrospinning technology have enabled the fabrication of precisely aligned nanofiber scaffolds with nanoscale architectures. These innovative methods also facilitate the fabrication of biomimetic structures, wherein bioactive substances can be incorporated and released in a controlled manner for drug delivery purposes. Moreover, they address issues encountered with traditional electrospun nanofibers, such as mechanical characteristics and biocompatibility. Consequently, the development and implementation of novel electrospinning technologies have revolutionized scaffold fabrication for bone tissue engineering.

Decellularized Umbilical Cord as a Scaffold to Support Healing of Full-Thickness Wounds

The umbilical cord is a material that enhances regeneration and is devoid of age-related changes in the extracellular matrix (ECM). The aim of this work was to develop a biodegradable scaffold from a decellularized human umbilical cord (UC-scaffold) to heal full-thickness wounds. Decellularization was performed with 0.05% sodium dodecyl sulfate solution. The UC-scaffold was studied using morphological analysis methods. The composition of the UC-scaffold was studied using immunoblotting and Fourier transform infrared spectroscopy. The adhesion and proliferation of mesenchymal stromal cells were investigated using the LIVE/DEAD assay. The local reaction was determined by subcutaneous implantation in mice (n = 60). A model of a full-thickness skin wound in mice (n = 64) was used to assess the biological activity of the UC-scaffold. The proposed decellularization method showed its effectiveness in the umbilical cord, as it removed cells and retained a porous structure, type I and type IV collagen, TGF-β3, VEGF, and fibronectin in the ECM. The biodegradation of the UC-scaffold in the presence of collagenase, its stability during incubation in hyaluronidase solution, and its ability to swell by 1617 ± 120% were demonstrated. Subcutaneous scaffold implantation in mice showed gradual resorption of the product in vivo without the formation of a dense connective tissue capsule. Epithelialization of the wound occurred completely in contrast to the controls. All of these data suggest a potential for the use of the UC-scaffold.

Targeting Macrophage Polarization for Reinstating Homeostasis following Tissue Damage

Tissue regeneration and remodeling involve many complex stages. Macrophages are critical in maintaining micro-environmental homeostasis by regulating inflammation and orchestrating wound healing. They display high plasticity in response to various stimuli, showing a spectrum of functional phenotypes that vary from M1 (pro-inflammatory) to M2 (anti-inflammatory) macrophages. While transient inflammation is an essential trigger for tissue healing following an injury, sustained inflammation (e.g., in foreign body response to implants, diabetes or inflammatory diseases) can hinder tissue healing and cause tissue damage. Modulating macrophage polarization has emerged as an effective strategy for enhancing immune-mediated tissue regeneration and promoting better integration of implantable materials in the host. This article provides an overview of macrophages' functional properties followed by discussing different strategies for modulating macrophage polarization. Advances in the use of synthetic and natural biomaterials to fabricate immune-modulatory materials are highlighted. This reveals that the development and clinical application of more effective immunomodulatory systems targeting macrophage polarization under pathological conditions will be driven by a detailed understanding of the factors that regulate macrophage polarization and biological function in order to optimize existing methods and generate novel strategies to control cell phenotype.

Enhancing electrical conductivity and mechanical properties of decellularized umbilical cord arteries using graphene coatings

Traditional decellularized bioscaffolds possessing intact vascular networks and unique architecture have been extensively studied as conduits for repairing nerve damage. However, they are limited by the absence of electrical conductivity, which is crucial for proper functioning of nervous tissue. This study focuses on investigating decellularized umbilical cord arteries by applying coatings of graphene oxide (GO) and reduced graphene oxide (RGO) to their inner surfaces. This resulted in a homogeneous GO coating that fully covered the internal lumen of the arteries. The results of electrical measurements demonstrated that the conductivity of the scaffolds could be significantly enhanced by incorporating RGO and GO conductive sheets. At a low frequency of 0.1 Hz, the electrical resistance level of the coated scaffolds decreased by 99.8% with RGO and 98.21% with GO, compared with uncoated scaffolds. Additionally, the mechanical properties of the arteries improved by 24.69% with GO and 32.9% with RGO after the decellularization process. The GO and RGO coatings did not compromise the adhesion of endothelial cells and promoted cell growth. The cytotoxicity tests revealed that cell survival rate increased over time with RGO, while it decreased with GO, indicating the time-dependent effect on the cytotoxicity of GO and RGO. Blood compatibility evaluations showed that graphene nanomaterials did not induce hemolysis but exhibited some tendency toward blood coagulation.

Hydrogel-Based 3D Bioprinting Technology for Articular Cartilage Regenerative Engineering

Articular cartilage is an avascular tissue with very limited capacity of self-regeneration. Trauma or injury-related defects, inflammation, or aging in articular cartilage can induce progressive degenerative joint diseases such as osteoarthritis. There are significant clinical demands for the development of effective therapeutic approaches to promote articular cartilage repair or regeneration. The current treatment modalities used for the repair of cartilage lesions mainly include cell-based therapy, small molecules, surgical approaches, and tissue engineering. However, these approaches remain unsatisfactory. With the advent of three-dimensional (3D) bioprinting technology, tissue engineering provides an opportunity to repair articular cartilage defects or degeneration through the construction of organized, living structures composed of biomaterials, chondrogenic cells, and bioactive factors. The bioprinted cartilage-like structures can mimic native articular cartilage, as opposed to traditional approaches, by allowing excellent control of chondrogenic cell distribution and the modulation of biomechanical and biochemical properties with high precision. This review focuses on various hydrogels, including natural and synthetic hydrogels, and their current developments as bioinks in 3D bioprinting for cartilage tissue engineering. In addition, the challenges and prospects of these hydrogels in cartilage tissue engineering applications are also discussed.

Gelatin-Based Scaffolds with Carrageenan and Chitosan for Soft Tissue Regeneration

Motivated by the enormous potential of hydrogels in regenerative medicine, new biocompatible gelatin-based hybrid hydrogels were developed through a green process using poly(ethylene glycol) diglycidyl ether as a cross-linking agent, adding carrageenan and chitosan polysaccharides to the network to better mimic the hybrid composition of native extracellular matrix. Overall, the hydrogels show suitable structural stability, high porosity and pore interconnectivity, good swellability, and finally, biocompatibility. Their mechanical behavior, investigated by tensile and compression tests, appears to be characterized by nonlinear elasticity with high compliance values, fast stress-relaxation, and good strain reversibility with no sign of mechanical failure for compressive loading-unloading cycles at relatively high deformation levels of 50%. Degradation tests confirm the hydrogel bioresorbability by gradual hydrolysis, during which the structural integrity of both materials is maintained, while their mechanical behavior becomes more and more compliant. Human Umbilical Cord-derived Mesenchymal Stem Cells (hUC-MSCs) were used to test the hydrogels as potential carriers for cell delivery in tissue engineering. hUC-MSCs cultured inside the hydrogels show a homogenous distribution and maintain their growth and viability for at least 21 days of culture, with an increasing proliferation trend. Hence, this study contributes to a further understanding of the potential use of hybrid hydrogels and hUC-MSCs for a wide range of biomedical applications, particularly in soft tissue engineering.

Modern advances in spinal cord regeneration: hydrogel combined with neural stem cells

Severe spinal cord injuries (SCI) lead to loss of functional activity of the body below the injury site, affect a person's ability to self-care and have a direct impact on performance. Due to the structural features and functional role of the spinal cord in the body, the consequences of SCI cannot be completely overcome at the expense of endogenous regenerative potential and, developing over time, lead to severe complications years after injury. Thus, the primary task of this type of injury treatment is to create artificial conditions for the regenerative growth of damaged nerve fibers through the area of the SCI. Solving this problem is possible using tissue neuroengineering involving the technology of replacing the natural tissue environment with synthetic matrices (for example, hydrogels) in combination with stem cells, in particular, neural/progenitor stem cells (NSPCs). This approach can provide maximum stimulation and support for the regenerative growth of axons of damaged neurons and their myelination. In this review, we consider the currently available options for improving the condition after SCI (use of NSC transplantation or/and replacement of the damaged area of the SCI with a matrix, specifically a hydrogel). We emphasise the expediency and effectiveness of the hydrogel matrix + NSCs complex system used for the reconstruction of spinal cord tissue after injury. Since such a complex approach (a combination of tissue engineering and cell therapy), in our opinion, allows not only to creation of conditions for supporting endogenous regeneration or mechanical reconstruction of the spinal cord, but also to strengthen endogenous regeneration, prevent the spread of the inflammatory process, and promote the restoration of lost reflex, motor and sensory functions of the injured area of spinal cord.

Enhancing Osteoblast Differentiation from Adipose-Derived Stem Cells Using Hydrogels and Photobiomodulation: Overcoming In Vitro Limitations for Osteoporosis Treatment

Osteoporosis represents a widespread and debilitating chronic bone condition that is increasingly prevalent globally. Its hallmark features include reduced bone density and heightened fragility, which significantly elevate the risk of fractures due to the decreased presence of mature osteoblasts. The limitations of current pharmaceutical therapies, often accompanied by severe side effects, have spurred researchers to seek alternative strategies. Adipose-derived stem cells (ADSCs) hold considerable promise for tissue repair, albeit they encounter obstacles such as replicative senescence in laboratory conditions. In comparison, employing ADSCs within three-dimensional (3D) environments provides an innovative solution, replicating the natural extracellular matrix environment while offering a controlled and cost-effective in vitro platform. Moreover, the utilization of photobiomodulation (PBM) has emerged as a method to enhance ADSC differentiation and proliferation potential by instigating cellular stimulation and facilitating beneficial performance modifications. This literature review critically examines the shortcomings of current osteoporosis treatments and investigates the potential synergies between 3D cell culture and PBM in augmenting ADSC differentiation towards osteogenic lineages. The primary objective of this study is to assess the efficacy of combined 3D environments and PBM in enhancing ADSC performance for osteoporosis management. This research is notably distinguished by its thorough scrutiny of the existing literature, synthesis of recent advancements, identification of future research trajectories, and utilization of databases such as PubMed, Scopus, Web of Science, and Google Scholar for this literature review. Furthermore, the exploration of biomechanical and biophysical stimuli holds promise for refining treatment strategies. The future outlook suggests that integrating PBM with ADSCs housed within 3D environments holds considerable potential for advancing bone regeneration efforts. Importantly, this review aspires to catalyse further advancements in combined therapeutic strategies for osteoporosis regeneration.

Fabrication of polymeric microspheres for biomedical applications

Polymeric microspheres (PMs) have attracted great attention in the field of biomedicine in the last several decades due to their small particle size, special functionalities shown on the surface and high surface-to-volume ratio. However, how to fabricate PMs which can meet the clinical needs and transform laboratory achievements to industrial scale-up still remains a challenge. Therefore, advanced fabrication technologies are pursued. In this review, we summarize the technologies used to fabricate PMs, including emulsion-based methods, microfluidics, spray drying, coacervation, supercritical fluid and superhydrophobic surface-mediated method and their advantages and disadvantages. We also review the different structures, properties and functions of the PMs and their applications in the fields of drug delivery, cell encapsulation and expansion, scaffolds in tissue engineering, transcatheter arterial embolization and artificial cells. Moreover, we discuss existing challenges and future perspectives for advancing fabrication technologies and biomedical applications of PMs.

Scaffold-Mediated Drug Delivery for Enhanced Wound Healing: A Review

Wound healing is a complex physiological process involving coordinated cellular and molecular events aimed at restoring tissue integrity. Acute wounds typically progress through the sequential phases of hemostasis, inflammation, proliferation, and remodeling, while chronic wounds, such as venous leg ulcers and diabetic foot ulcers, often exhibit prolonged inflammation and impaired healing. Traditional wound dressings, while widely used, have limitations such poor moisture retention and biocompatibility. To address these challenges and improve patient outcomes, scaffold-mediated delivery systems have emerged as innovative approaches. They offer advantages in creating a conducive environment for wound healing by facilitating controlled and localized drug delivery. The manuscript explores scaffold-mediated delivery systems for wound healing applications, detailing the use of natural and synthetic polymers in scaffold fabrication. Additionally, various fabrication techniques are discussed for their potential in creating scaffolds with controlled drug release kinetics. Through a synthesis of experimental findings and current literature, this manuscript elucidates the promising potential of scaffold-mediated drug delivery in improving therapeutic outcomes and advancing wound care practices.

Electrohydrodynamic Direct-Writing Micro/Nanofibrous Architectures: Principle, Materials, and Biomedical Applications

Electrohydrodynamic (EHD) direct-writing has recently gained attention as a highly promising additive manufacturing strategy for fabricating intricate micro/nanoscale architectures. This technique is particularly well-suited for mimicking the extracellular matrix (ECM) present in biological tissue, which serves a vital function in facilitating cell colonization, migration, and growth. The integration of EHD direct-writing with other techniques has been employed to enhance the biological performance of scaffolds, and significant advancements have been made in the development of tailored scaffold architectures and constituents to meet the specific requirements of various biomedical applications. Here, a comprehensive overview of EHD direct-writing is provided, including its underlying principles, demonstrated materials systems, and biomedical applications. A brief chronology of EHD direct-writing is provided, along with an examination of the observed phenomena that occur during the printing process. The impact of biomaterial selection and architectural topographic cues on biological performance is also highlighted. Finally, the major limitations associated with EHD direct-writing are discussed.

Challenges and Pitfalls of Research Designs Involving Magnesium-Based Biomaterials: An Overview

Magnesium-based biomaterials hold remarkable promise for various clinical applications, offering advantages such as reduced stress-shielding and enhanced bone strengthening and vascular remodeling compared to traditional materials. However, ensuring the quality of preclinical research is crucial for the development of these implants. To achieve implant success, an understanding of the cellular responses post-implantation, proper model selection, and good study design are crucial. There are several challenges to reaching a safe and effective translation of laboratory findings into clinical practice. The utilization of Mg-based biomedical devices eliminates the need for biomaterial removal surgery post-healing and mitigates adverse effects associated with permanent biomaterial implantation. However, the high corrosion rate of Mg-based implants poses challenges such as unexpected degradation, structural failure, hydrogen evolution, alkalization, and cytotoxicity. The biocompatibility and degradability of materials based on magnesium have been studied by many researchers in vitro; however, evaluations addressing the impact of the material in vivo still need to be improved. Several animal models, including rats, rabbits, dogs, and pigs, have been explored to assess the potential of magnesium-based materials. Moreover, strategies such as alloying and coating have been identified to enhance the degradation rate of magnesium-based materials in vivo to transform these challenges into opportunities. This review aims to explore the utilization of Mg implants across various biomedical applications within cellular (in vitro) and animal (in vivo) models.

Biodegradable polyester copolymers: synthesis based on the Biginelli reaction, characterization, and evaluation of their application properties

The Biginelli reaction, a three-component cyclocondensation reaction, is an important member of the multicomponent reaction (MCR) family. In this study, we conducted end-group modifications on a variety of biodegradable polyesters, including poly(1,4-butylene adipate) (PBA), poly(ε-caprolactone) (PCL), polylactic acid (PLA), and poly(p-dioxanone) (PPDO), based on the precursor polyethylene glycol (PEG). By combining two polymers through the Biginelli multi-component reaction, four new biodegradable polyester copolymers, namely DHPM-PBA, DHPM-PCL, DHPM-PLA, and DHPM-PPDO, were formed. These Biginelli reactions demonstrated exceptional completeness, validating the efficiency of the synthesis strategy. Although the introduction of various polyesters lead to different properties, such as crystallinity and cytotoxicity, the newly synthesized 3,4-dihydro-2(H)-pyrimidinone compounds (DHPMs) exhibit enhanced hydrophilicity and can self-assemble in water and N,N-dimethylformamide (DMF) solution to form micelles with a controllable size. Furthermore, DHPM-PPDO promotes cellular growth and has potential applications in wound healing and tissue engineering. In conclusion, this method demonstrates great universality and methodological significance and offers insights into the medical applications of polyethylene glycol.

Production of Agarose-Hydroxyapatite Composites via Supercritical Gel Drying, for Bone Tissue Engineering

Bone tissue engineering (BTE) is the most promising strategy to repair bones injuries and defects. It relies on the utilization of a temporary support to host the cells and promote nutrient exchange (i.e., the scaffold). Supercritical CO2 assisted drying can preserve scaffold nanostructure, crucial for cell attachment and proliferation. In this work, agarose aerogels, loaded with hydroxyapatite were produced in view of BTE applications. Different combinations of agarose concentration and hydroxyapatite loadings were tested. FESEM and EDX analyses showed that scaffold structure suffered from partial closure when increasing filler concentration; hydroxyapatite distribution was homogenous, and Young's modulus improved. Looking at BTE applications, the optimal combination of agarose and hydroxyapatite resulted to be 1% w/w and 10% w/v, respectively. Mechanical properties showed that the produced composites could be eligible as starting scaffold for BTE, with a Young's Modulus larger than 100 kPa for every blend.

Synthesis of Chitosan and Ferric-Ion (Fe3+)-Doped Brushite Mineral Cancellous Bone Scaffolds

Biodegradable scaffolds are needed to repair bone defects. To promote the resorption of scaffolds, a large surface area is required to encourage neo-osteogenesis. Herein, we describe the synthesis and freeze-drying methodologies of ferric-ion (Fe3+) doped Dicalcium Phosphate Dihydrate mineral (DCPD), also known as brushite, which has been known to favour the in situ condition for osteogenesis. In this investigation, the role of chitosan during the synthesis of DCPD was explored to enhance the antimicrobial, scaffold pore distribution, and mechanical properties post freeze-drying. During the synthesis of DCPD, the calcium nitrate solution was hydrolysed with a predetermined stoichiometric concentration of ammonium phosphate. During the hydrolysis reaction, 10 (mol)% iron (Fe3+) nitrate (Fe(NO3)3) was incorporated, and the DCPD minerals were precipitated (Fe3+-DCPD). Chitosan stir-mixed with Fe3+-DCPD minerals was freeze-dried to create scaffolds. The structural, microstructural, and mechanical properties of freeze-dried materials were characterized.

Diaminated Cellulose Beads as a Sustainable Support for Industrially Relevant Lipases

Environmentally persistent polystyrene or polyacrylic beads are used as supports in enzyme large-scale bioprocesses, including conversion glucose isomerization for high-fructose corn syrup production, hydrolysis of lactose, and synthesis of active pharmaceutical ingredients. In this paper, we report the development of a novel sustainable and scalable method to produce diaminated cellulose beads (DAB) as highly efficient alternative supports for industrially relevant lipases. Regenerated cellulose beads were grafted with diaminated aliphatic hydrocarbons via periodate oxidation and reductive amination. The oxidation step indicated that aldehyde content can be easily tuned through the reaction time and concentration of reactants. Reductive amination of dialdehyde cellulose was more efficient as the length of the diaminated hydrocarbon compound increased. Morphological analysis of DAB showed that cellulose chemical grafting enabled the preservation of the bead shape and internal structure upon freeze-drying. Enzymatic degradability studies demonstrated that chemical functionalization did not undermine enzyme cellulose hydrolysis. The addition of aminated moieties on cellulose dramatically increased absorption efficiency for all industrially relevant lipases used, reaching 100% for Thermomyces lanuginosus lipase (TLL). Storage and recyclability experiments demonstrated that enzymes were retained and recyclable for at least nine cycles, although the activity gradually declined after each cycle. Medium chain triacylglycerol hydrolysis in a SpinChem reactor using TLL immobilized on 1,6 DAB exhibited higher activity compared to acrylic beads (588 vs 459 U/g) suggesting that biodegradable cellulose-based materials could be a valid and attractive alternative to plastics carriers.

A Review of Recent Developments in Biopolymer Nano-Based Drug Delivery Systems with Antioxidative Properties: Insights into the Last Five Years

In recent years, biopolymer-based nano-drug delivery systems with antioxidative properties have gained significant attention in the field of pharmaceutical research. These systems offer promising strategies for targeted and controlled drug delivery while also providing antioxidant effects that can mitigate oxidative stress-related diseases. Generally, the healthcare landscape is constantly evolving, necessitating the continual development of innovative therapeutic approaches and drug delivery systems (DDSs). DDSs play a pivotal role in enhancing treatment efficacy, minimizing adverse effects, and optimizing patient compliance. Among these, nanotechnology-driven delivery approaches have garnered significant attention due to their unique properties, such as improved solubility, controlled release, and targeted delivery. Nanomaterials, including nanoparticles, nanocapsules, nanotubes, etc., offer versatile platforms for drug delivery and tissue engineering applications. Additionally, biopolymer-based DDSs hold immense promise, leveraging natural or synthetic biopolymers to encapsulate drugs and enable targeted and controlled release. These systems offer numerous advantages, including biocompatibility, biodegradability, and low immunogenicity. The utilization of polysaccharides, polynucleotides, proteins, and polyesters as biopolymer matrices further enhances the versatility and applicability of DDSs. Moreover, substances with antioxidative properties have emerged as key players in combating oxidative stress-related diseases, offering protection against cellular damage and chronic illnesses. The development of biopolymer-based nanoformulations with antioxidative properties represents a burgeoning research area, with a substantial increase in publications in recent years. This review provides a comprehensive overview of the recent developments within this area over the past five years. It discusses various biopolymer materials, fabrication techniques, stabilizers, factors influencing degradation, and drug release. Additionally, it highlights emerging trends, challenges, and prospects in this rapidly evolving field.

Evolutionary trends and innovations in cardiovascular intervention

Cardiovascular diseases remain a global health challenge, prompting continuous innovation in medical technology, particularly in Cardiovascular MedTech. This article provides a comprehensive exploration of the transformative landscape of Cardiovascular MedTech in the 21st century, focusing on interventions. The escalating prevalence of cardiovascular diseases and the demand for personalized care drive the evolving landscape, with technologies like wearables and AI reshaping patient-centric healthcare. Wearable devices offer real-time monitoring, enhancing procedural precision and patient outcomes. AI facilitates risk assessment and personalized treatment strategies, revolutionizing intervention precision. Minimally invasive procedures, aided by robotics and novel materials, minimize patient impact and improve outcomes. 3D printing enables patient-specific implants, while regenerative medicine promises cardiac regeneration. Augmented reality headsets empower surgeons during procedures, enhancing precision and awareness. Novel materials and radiation reduction techniques further optimize interventions, prioritizing patient safety. Data security measures ensure patient privacy in the era of connected healthcare. Modern technologies enhance traditional surgeries, refining outcomes. The integration of these innovations promises to shape a healthier future for cardiovascular procedures, emphasizing collaboration and research to maximize their transformative potential.

Unveiling the potential of biomaterials and their synergistic fusion in tissue engineering

Inspired by nature, tissue engineering aims to employ intricate mechanisms for advanced clinical interventions, unlocking inherent biological potential and propelling medical breakthroughs. Therefore, medical, and pharmaceutical fields are growing interest in tissue and organ replacement, repair, and regeneration by this technology. Three primary mechanisms are currently used in tissue engineering: transplantation of cells (I), injection of growth factors (II) and cellular seeding in scaffolds (III). However, to develop scaffolds presenting highest potential, reinforcement with polymeric materials is growing interest. For instance, natural and synthetic polymers can be used. Regardless, chitosan and keratin are two biopolymers presenting great biocompatibility, biodegradability and non-antigenic properties for tissue engineering purposes offering restoration and revitalization. Therefore, combination of chitosan and keratin has been studied and results exhibit highly porous scaffolds providing optimal environment for tissue cultivation. This review aims to give an historical as well as current overview of tissue engineering, presenting mechanisms used and polymers involved in the field.

An examination of recent research of water absorption behavior of natural fiber reinforced polylactic acid (PLA) composites: A review

Researchers have begun focusing on developing biodegradable materials, such as natural fiber/polymer composites (NFPC), since the growing of environmental concerns related to waste management. One crucial aspect that must be established in the development of these composites is their water-absorption behavior. This paper examines the water absorption (WA) behavior of NFPC, with a specific emphasis on natural fiber/polylactic acid (PLA) composites. It discusses processes and numerous aspects related to this behavior, based on recent published research. This review analyzes the influence of several factors, such as the loading of natural fiber, the combination of different natural fibers, the methods used in manufacturing, and the temperature of the water, on the WA behavior of natural fiber/PLA composites. It also explores how WA affects the properties of these composites. In addition, this review also presented techniques for improving the WA resistance of the composites. This review paper provides researchers with insights into the WA behavior of the composites, aiming to facilitate the development of a versatile and eco-friendly material that may effectively address waste disposal challenges.

Advances in natural and synthetic macromolecules with stem cells and extracellular vesicles for orthopedic disease treatment

Serious orthopedic disorders resulting from myriad diseases and impairments continue to pose a considerable challenge to contemporary clinical care. Owing to its limited regenerative capacity, achieving complete bone tissue regeneration and complete functional restoration has proven challenging with existing treatments. By virtue of cellular regenerative and paracrine pathways, stem cells are extensively utilized in the restoration and regeneration of bone tissue; however, low survival and retention after transplantation severely limit their therapeutic effect. Meanwhile, biomolecule materials provide a delivery platform that improves stem cell survival, increases retention, and enhances therapeutic efficacy. In this review, we present the basic concepts of stem cells and extracellular vesicles from different sources, emphasizing the importance of using appropriate expansion methods and modification strategies. We then review different types of biomolecule materials, focusing on their design strategies. Moreover, we summarize several forms of biomaterial preparation and application strategies as well as current research on biomacromolecule materials loaded with stem cells and extracellular vesicles. Finally, we present the challenges currently impeding their clinical application for the treatment of orthopedic diseases. The article aims to provide researchers with new insights for subsequent investigations.

Natural and Synthetic Polymers for Biomedical and Environmental Applications

Natural and synthetic polymers are a versatile platform for developing biomaterials in the biomedical and environmental fields. Natural polymers are organic compounds that are found in nature. The most common natural polymers include polysaccharides, such as alginate, hyaluronic acid, and starch, proteins, e.g., collagen, silk, and fibrin, and bacterial polyesters. Natural polymers have already been applied in numerous sectors, such as carriers for drug delivery, tissue engineering, stem cell morphogenesis, wound healing, regenerative medicine, food packaging, etc. Various synthetic polymers, including poly(lactic acid), poly(acrylic acid), poly(vinyl alcohol), polyethylene glycol, etc., are biocompatible and biodegradable; therefore, they are studied and applied in controlled drug release systems, nano-carriers, tissue engineering, dispersion of bacterial biofilms, gene delivery systems, bio-ink in 3D-printing, textiles in medicine, agriculture, heavy metals removal, and food packaging. In the following review, recent advancements in polymer chemistry, which enable the imparting of specific biomedical functions of polymers, will be discussed in detail, including antiviral, anticancer, and antimicrobial activities. This work contains the authors' experimental contributions to biomedical and environmental polymer applications. This review is a vast overview of natural and synthetic polymers used in biomedical and environmental fields, polymer synthesis, and isolation methods, critically assessessing their advantages, limitations, and prospects.

Functionalization of PCL-Based Fiber Scaffolds with Different Sources of Calcium and Phosphate and Odontogenic Potential on Human Dental Pulp Cells

This study investigated the incorporation of sources of calcium, phosphate, or both into electrospun scaffolds and evaluated their bioactivity on human dental pulp cells (HDPCs). Additionally, scaffolds incorporated with calcium hydroxide (CH) were characterized for degradation, calcium release, and odontogenic differentiation by HDPCs. Polycaprolactone (PCL) was electrospun with or without 0.5% w/v of calcium hydroxide (PCL + CH), nano-hydroxyapatite (PCL + nHA), or β-glycerophosphate (PCL + βGP). SEM/EDS analysis confirmed fibrillar morphology and particle incorporation. HDPCs were cultured on the scaffolds to assess cell viability, adhesion, spreading, and mineralized matrix formation. PCL + CH was also evaluated for gene expression of odontogenic markers (RT-qPCR). Data were submitted to ANOVA and Student's t-test (α = 5%). Added CH increased fiber diameter and interfibrillar spacing, whereas βGP decreased both. PCL + CH and PCL + nHA improved HDPC viability, adhesion, and proliferation. Mineralization was increased eightfold with PCL + CH. Scaffolds containing CH gradually degraded over six months, with calcium release within the first 140 days. CH incorporation upregulated DSPP and DMP1 expression after 7 and 14 days. In conclusion, CH- and nHA-laden PCL fiber scaffolds were cytocompatible and promoted HDPC adhesion, proliferation, and mineralized matrix deposition. PCL + CH scaffolds exhibit a slow degradation profile, providing sustained calcium release and stimulating HDPCs to upregulate odontogenesis marker genes.

Recent Progress of Carrageenan-Based Composite Films in Active and Intelligent Food Packaging Applications

Recently, as concerns about petrochemical-derived polymers increase, interest in biopolymer-based materials is increasing. Undoubtedly, biopolymers are a better alternative to solve the problem of synthetic polymer-based plastics for packaging purposes. There are various types of biopolymers in nature, and mostly polysaccharides are used in this regard. Carrageenan is a hydrophilic polysaccharide extracted from red algae and has recently attracted great interest in the development of food packaging films. Carrageenan is known for its excellent film-forming properties, high compatibility and good carrier properties. Carrageenan is readily available and low cost, making it a good candidate as a polymer matrix base material for active and intelligent food packaging films. The carrageenan-based packaging film lacks mechanical, barrier, and functional properties. Thus, the physical and functional properties of carrageenan-based films can be enhanced by blending this biopolymer with functional compounds and nanofillers. Various types of bioactive ingredients, such as nanoparticles, natural extracts, colorants, and essential oils, have been incorporated into the carrageenan-based film. Carrageenan-based functional packaging film was found to be useful for extending the shelf life of packaged foods and tracking spoilage. Recently, there has been plenty of research work published on the potential of carrageenan-based packaging film. Therefore, this review discusses recent advances in carrageenan-based films for applications in food packaging. The preparation and properties of carrageenan-based packaging films were discussed, as well as their application in real-time food packaging. The latest discussion on the potential of carrageenan as an alternative to traditionally used synthetic plastics may be helpful for further research in this field.

The Evolution of Technology-Driven In Vitro Models for Neurodegenerative Diseases

The alteration in the neural circuits of both central and peripheral nervous systems is closely related to the onset of neurodegenerative disorders (NDDs). Despite significant research efforts, the knowledge regarding NDD pathological processes, and the development of efficacious drugs are still limited due to the inability to access and reproduce the components of the nervous system and its intricate microenvironment. 2D culture systems are too simplistic to accurately represent the more complex and dynamic situation of cells in vivo and have therefore been surpassed by 3D systems. However, both models suffer from various limitations that can be overcome by employing two innovative technologies: organ-on-chip and 3D printing. In this review, an overview of the advantages and shortcomings of both microfluidic platforms and extracellular matrix-like biomaterials will be given. Then, the combination of microfluidics and hydrogels as a new synergistic approach to study neural disorders by analyzing the latest advances in 3D brain-on-chip for neurodegenerative research will be explored.

3D printed arrowroot starch-gellan scaffolds for wound healing applications

Skin, the largest organ in the body, blocks the entry of environmental pollutants into the system. Any injury to this organ allows infections and other harmful substances into the body. 3D bioprinting, a state-of-the-art technique, is suitable for fabricating cell culture scaffolds to heal chronic wounds rapidly. This study uses starch extracted from Maranta arundinacea (Arrowroot plant) (AS) and gellan gum (GG) to develop a bioink for 3D printing a scaffold capable of hosting animal cells. Field emission scanning electron microscopy (FE-SEM) and X-ray diffraction analysis (XRD) prove that the isolated AS is analogous to commercial starch. The cell culture scaffolds developed are superior to the existing monolayer culture. Infrared microscopy shows the AS-GG interaction and elucidates the mechanism of hydrogel formation. The physicochemical properties of the 3D-printed scaffold are analyzed to check the cell adhesion and growth; SEM images have confirmed that the AS-GG printed scaffold can support cell growth and proliferation, and the MTT assay shows good cell viability. Cell behavioral and migration studies reveal that cells are healthy. Since the scaffold is biocompatible, it can be 3D printed to any shape and structure and will biodegrade in the requisite time.

Extracellular matrix-derived materials for tissue engineering and regenerative medicine: A journey from isolation to characterization and application

Biomaterial choice is an essential step during the development tissue engineering and regenerative medicine (TERM) applications. The selected biomaterial must present properties allowing the physiological-like recapitulation of several processes that lead to the reestablishment of homeostatic tissue or organ function. Biomaterials derived from the extracellular matrix (ECM) present many such properties and their use in the field has been steadily increasing. Considering this growing importance, it becomes imperative to provide a comprehensive overview of ECM biomaterials, encompassing their sourcing, processing, and integration into TERM applications. This review compiles the main strategies used to isolate and process ECM-derived biomaterials as well as different techniques used for its characterization, namely biochemical and chemical, physical, morphological, and biological. Lastly, some of their applications in the TERM field are explored and discussed.

Surface-modified deproteinized human demineralized tooth matrix for bone regeneration: physicochemical characterization and osteoblast cell biocompatibility

Tooth presents an intriguing option as a bone graft due to its compositional similarity to bone. However, the deproteinized human demineralized tooth matrix (dpDTM), developed to overcome the limited availability of autologous tooth grafts, has suboptimal pore size and surface roughness. This study aimed to fabricate a surface-modified dpDTM using acid etching and collagen coating, followed by in vitro evaluation of physicochemical and biological properties. The dpDTM was modified into two protocols: Acid-modified dpDTM (A-dpDTM) and collagen-modified dpDTM (C-dpDTM). Results demonstrated that A-dpDTM and C-dpDTM had increased pore sizes and rougher surfaces compared to dpDTM. Collagen immobilization was evidenced by nitrogen presence exclusively in C-dpDTM. All groups had a Ca/P molar ratio of 1.67 and hydroxyapatite as the sole constituent, with 65-67% crystallinity. Degradation rates significantly increased to 30% and 20% for C-dpDTM and A-dpDTM, respectively, compared to 10% for dpDTM after 120 days. Cumulative collagen release of C-dpDTM on Day 30 was 45.16 µg/ml. Osteoblasts attachment and proliferation were enhanced on all scaffolds, especially C-dpDTM, which displayed the highest proliferation and differentiation rates. In conclusion, surface modified of dpDTM, including A-dpDTM and C-dpDTM, significantly enhances bioactivity by altering surface properties and promoting osteoblast activity, thereby demonstrating promise for bone regeneration applications.

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.

Nanotechnology in development of next generation of stent and related medical devices: Current and future aspects

Coronary stents have saved millions of lives in the last three decades by treating atherosclerosis especially, by preventing plaque protrusion and subsequent aneurysms. They attenuate the vascular SMC proliferation and promote reconstruction of the endothelial bed to ensure superior revascularization. With the evolution of modern stent types, nanotechnology has become an integral part of stent technology. Nanocoating and nanosurface fabrication on metallic and polymeric stents have improved their drug loading capacity as well as other mechanical, physico-chemical, and biological properties. Nanofeatures can mimic the natural nanofeatures of vascular tissue and control drug-delivery. This review will highlight the role of nanotechnology in addressing the challenges of coronary stents and the recent advancements in the field of related medical devices. Different generations of stents carrying nanoparticle-based formulations like liposomes, lipid-polymer hybrid NPs, polymeric micelles, and dendrimers are discussed highlighting their roles in local drug delivery and anti-restenotic properties. Drug nanoparticles like Paclitaxel embedded in metal stents are discussed as a feature of first-generation drug-eluting stents. Customized precision stents ensure safe delivery of nanoparticle-mediated genes or concerted transfer of gene, drug, and/or bioactive molecules like antibodies, gene mimics via nanofabricated stents. Nanotechnology can aid such therapies for drug delivery successfully due to its easy scale-up possibilities. However, limitations of this technology such as their potential cytotoxic effects associated with nanoparticle delivery that can trigger hypersensitivity reactions have also been discussed in this review. This article is categorized under: Implantable Materials and Surgical Technologies > Nanotechnology in Tissue Repair and Replacement Therapeutic Approaches and Drug Discovery > Nanomedicine for Cardiovascular Disease Therapeutic Approaches and Drug Discovery > Emerging Technologies.

Developing natural polymers for skin wound healing

Natural polymers are complex organic molecules that occur in the natural environment and have not been subjected to artificial synthesis. They are frequently encountered in various creatures, including mammals, plants, and microbes. The aforementioned polymers are commonly derived from renewable sources, possess a notable level of compatibility with living organisms, and have a limited adverse effect on the environment. As a result, they hold considerable significance in the development of sustainable and environmentally friendly goods. In recent times, there has been notable advancement in the investigation of the potential uses of natural polymers in the field of biomedicine, specifically in relation to natural biomaterials that exhibit antibacterial and antioxidant characteristics. This review provides a comprehensive overview of prevalent natural polymers utilized in the biomedical domain throughout the preceding two decades. In this paper, we present a comprehensive examination of the components and typical methods for the preparation of biomaterials based on natural polymers. Furthermore, we summarize the application of natural polymer materials in each stage of skin wound repair. Finally, we present key findings and insights into the limitations of current natural polymers and elucidate the prospects for their future development in this field.

Characterization and biocompatibility evaluation of acellular rat skin scaffolds for skin tissue engineering applications

Utilization of acellular scaffolds, extracellular matrix (ECM) without cell content, is growing in tissue engineering, due to their high biocompatibility, bioactivity ad mechanical support. Hence, the purpose of this research was to study the characteristics and biocompatibility of decellularized rat skin scaffolds using the osmotic shock method. First, the skin of male Wistar rats was harvested and cut into 1 × 1 cm2 pieces. Then, some of the harvested parts were subjected to the decellularization process by applying osmotic shock. Comparison of control and scaffold samples was conducted in order to assure cell elimination and ECM conservation by means of histological evaluations, quantification of biochemical factors, measurement of DNA amount, and photographing the ultrastructure of the samples by scanning electron microscopy (SEM). In order to evaluate stem cell viability and adhesion to the scaffold, adipose-derived mesenchymal stem cells (AD-MSCs) were seeded on the acellular scaffolds. Subsequently, MTT test and SEM imaging of the scaffolds containing cultured cells were applied. The findings indicated that in the decellularized scaffolds prepared by osmotic shock method, not only the cell content was removed, but also the ECM components and its ultrastructure were preserved. Also, the 99% viability and adhesion of AD-MSCs cultured on the scaffolds indicate the biocompatibility of the decellularized skin scaffold. In conclusion, decellularized rat skin scaffolds are biocompatible and appropriate scaffolds for future investigations of tissue engineering applications.

Recent Advances in Scaffolds for Guided Bone Regeneration

The rehabilitation of alveolar bone defects of moderate to severe size is often challenging. Currently, the therapeutic approaches used include, among others, the guided bone regeneration technique combined with various bone grafts. Although these techniques are widely applied, several limitations and complications have been reported such as morbidity, suboptimal graft/membrane resorption rate, low structural integrity, and dimensional stability. Thus, the development of biomimetic scaffolds with tailor-made characteristics that can modulate cell and tissue interaction may be a promising tool. This article presents a critical consideration in scaffold's design and development while also providing information on various fabrication methods of these nanosystems. Their utilization as delivery systems will also be mentioned.

Enhancement of Wound Healing and Angiogenesis Using Mouse Embryo Fibroblasts Loaded in Decellularized Skin Scaffold

Background

Synthetic and natural polymer scaffolds can be used to design wound dressing for repairing the damaged skin tissue. This study investigated acute wound healing process using a decellularized skin scaffold and mouse embryo fibroblast (MEF).

Methods

Mouse skin fragments were decellularized and evaluated by DNA content, toxicity, H&E staining, Raman confocal microscopy, Masson’s trichrome staining, SEM, and biodegradation assays. The fragments were recellularized by the MEFs, and cell attachment and penetration were studied. De- and decellularized scaffolds were used wound dressings in mouse acute wound models as two experimental groups. Using morphological and immunohistochemical assessments, wound healing was evaluated and compared among the experimental and control groups.

Results

DNA content of the decellularized tissue significantly reduced compared to the native control group (7% vs. 100%; p < 0.05). extracellular matrix components, e.g. collagen types I, III, and IV, elastin, and glycosaminoglycan, were well preserved in the decellularized group. The porosity and fiber arrangement in the stroma had a structure similar to normal skin tissue. A significant reduction in healing time was observed in the group treated with a decellularized scaffold. A thicker epidermis layer was observed in the recovered tissue in both experimental groups compared to the control group. Immunostaining showed a positive reaction for CD31 as an endothelial marker in both experimental groups, confirming new vascularization in these groups.

Conclusion

Using MEFs with decellularized skin as a wound dressing increases the rate of wound healing and also the formation of new capillaries. This system could be beneficial for clinical applications in the field of tissue engineering.

Additive and Lithographic Manufacturing of Biomedical Scaffold Structures Using a Versatile Thiol-Ene Photocurable Resin

Additive and lithographic manufacturing technologies using photopolymerisation provide a powerful tool for fabricating multiscale structures, which is especially interesting for biomimetic scaffolds and biointerfaces. However, most resins are tailored to one particular fabrication technology, showing drawbacks for versatile use. Hence, we used a resin based on thiol-ene chemistry, leveraging its numerous advantages such as low oxygen inhibition, minimal shrinkage and high monomer conversion. The resin is tailored to applications in additive and lithographic technologies for future biofabrication where fast curing kinetics in the presence of oxygen are required, namely 3D inkjet printing, digital light processing and nanoimprint lithography. These technologies enable us to fabricate scaffolds over a span of six orders of magnitude with a maximum of 10 mm and a minimum of 150 nm in height, including bioinspired porous structures with controlled architecture, hole-patterned plates and micro/submicro patterned surfaces. Such versatile properties, combined with noncytotoxicity, degradability and the commercial availability of all the components render the resin as a prototyping material for tissue engineers.

Trends of regenerative tissue engineering for oral and maxillofacial reconstruction in veterinary medicine

Oral and maxillofacial (OMF) defects are not limited to humans and are often encountered in other species. Reconstructing significant tissue defects requires an excellent strategy for efficient and cost-effective treatment. In this regard, tissue engineering comprising stem cells, scaffolds, and signaling molecules is emerging as an innovative approach to treating OMF defects in veterinary patients. This review presents a comprehensive overview of OMF defects and tissue engineering principles to establish proper treatment and achieve both hard and soft tissue regeneration in veterinary practice. Moreover, bench-to-bedside future opportunities and challenges of tissue engineering usage are also addressed in this literature review.

Characterization of an Injectable Chitosan Hydrogel for the Tunable, Localized Delivery of Immunotherapeutics

Localized delivery of immunotherapeutics within a tumor has the potential to reduce systemic toxicities and improve treatment outcomes in cancer patients. Unfortunately, local retention of therapeutics following intratumoral injection is problematic and is insufficiently considered. Dense tumor architectures and high interstitial pressures rapidly exclude injections of saline and other low-viscosity solutions. Hydrogel-based delivery systems, on the other hand, can resist shear forces that cause tumor leakage and thus stand to improve the local retention of coformulated therapeutics. The goal of the present work was to construct a novel, injectable hydrogel that could be tuned for localized immunotherapy delivery. A chitosan-based hydrogel, called XCSgel, was developed and subsequently characterized. Nuclear magnetic resonance studies were performed to describe the chemical properties of the new entity, while cryo-scanning electron microscopy allowed for visualization of the hydrogel's cross-linked network. Rheology experiments demonstrated that XCSgel was shear-thinning and self-healing. Biocompatibility studies, both in vitro and in vivo, showed that XCSgel was nontoxic and induced transient mild-to-moderate inflammation. Release studies revealed that coformulated immunotherapeutics were released over days to weeks in a charge-dependent manner. Overall, XCSgel displayed several clinically important features, including injectability, biocompatibility, and imageability. Furthermore, the properties of XCSgel could also be controlled to tune the release of coformulated immunotherapeutics.

A Comprehensive Review of Muscle-Tendon Junction: Structure, Function, Injury and Repair

The muscle-tendon junction (MTJ) is a highly specific tissue interface where the muscle's fascia intersects with the extracellular matrix of the tendon. The MTJ functions as the particular structure facilitating the transmission of force from contractive muscle fibers to the skeletal system, enabling movement. Considering that the MTJ is continuously exposed to constant mechanical forces during physical activity, it is susceptible to injuries. Ruptures at the MTJ often accompany damage to both tendon and muscle tissues. In this review, we attempt to provide a precise definition of the MTJ, describe its subtle structure in detail, and introduce therapeutic approaches related to MTJ tissue engineering. We hope that our detailed illustration of the MTJ and summary of the representative research achievements will help researchers gain a deeper understanding of the MTJ and inspire fresh insights and breakthroughs for future research.

Electroactive 4D Porous Scaffold Based on Conducting Polymer as a Responsive and Dynamic In Vitro Cell Culture Platform

In vivo, cells reside in a 3D porous and dynamic microenvironment. It provides biochemical and biophysical cues that regulate cell behavior in physiological and pathological processes. In the context of fundamental cell biology research, tissue engineering, and cell-based drug screening systems, a challenge is to develop relevant in vitro models that could integrate the dynamic properties of the cell microenvironment. Taking advantage of the promising high internal phase emulsion templating, we here designed a polyHIPE scaffold with a wide interconnected porosity and functionalized its internal 3D surface with a thin layer of electroactive conducting polymer poly(3,4-ethylenedioxythiophene) (PEDOT) to turn it into a 4D electroresponsive scaffold. The resulting scaffold was cytocompatible with fibroblasts, supported cellular infiltration, and hosted cells, which display a 3D spreading morphology. It demonstrated robust actuation in ion- and protein-rich complex culture media, and its electroresponsiveness was not altered by fibroblast colonization. Thanks to customized electrochemical stimulation setups, the electromechanical response of the polyHIPE/PEDOT scaffolds was characterized in situ under a confocal microscope and showed 10% reversible volume variations. Finally, the setups were used to monitor in real time and in situ fibroblasts cultured into the polyHIPE/PEDOT scaffold during several cycles of electromechanical stimuli. Thus, we demonstrated the proof of concept of this tunable scaffold as a tool for future 4D cell culture and mechanobiology studies.

Recent Development of Implantable Chemical Sensors Utilizing Flexible and Biodegradable Materials for Biomedical Applications

Implantable chemical sensors built with flexible and biodegradable materials exhibit immense potential for seamless integration with biological systems by matching the mechanical properties of soft tissues and eliminating device retraction procedures. Compared with conventional hospital-based blood tests, implantable chemical sensors have the capability to achieve real-time monitoring with high accuracy of important biomarkers such as metabolites, neurotransmitters, and proteins, offering valuable insights for clinical applications. These innovative sensors could provide essential information for preventive diagnosis and effective intervention. To date, despite extensive research on flexible and bioresorbable materials for implantable electronics, the development of chemical sensors has faced several challenges related to materials and device design, resulting in only a limited number of successful accomplishments. This review highlights recent advancements in implantable chemical sensors based on flexible and biodegradable materials, encompassing their sensing strategies, materials strategies, and geometric configurations. The following discussions focus on demonstrated detection of various objects including ions, small molecules, and a few examples of macromolecules using flexible and/or bioresorbable implantable chemical sensors. Finally, we will present current challenges and explore potential future directions.

Reduced graphene oxide-reinforced tricalcium phosphate/gelatin/chitosan light-responsive scaffolds for application in bone regeneration

Bone is a mineralized tissue with the intrinsic capacity for constant remodeling. Rapid prototyping techniques, using biomaterials that mimic the bone native matrix, have been used to develop osteoinductive and osteogenic personalized 3D structures, which can be further combined with drug delivery and phototherapy. Herein, a Fab@Home 3D Plotter printer was used to promote the layer-by-layer deposition of a composite mixture of gelatin, chitosan, tricalcium phosphate, and reduced graphene oxide (rGO). The phototherapeutic potential of the new NIR-responsive 3D_rGO scaffolds was assessed by comparing scaffolds with different rGO concentrations (1, 2, and 4 mg/mL). The data obtained show that the rGO incorporation confers to the scaffolds the capacity to interact with NIR light and induce a hyperthermy effect, with a maximum temperature increase of 16.7 °C after under NIR irradiation (10 min). Also, the increase in the rGO content improved the hydrophilicity and mechanical resistance of the scaffolds, particularly in the 3D_rGO4. Furthermore, the rGO could confer an NIR-triggered antibacterial effect to the 3D scaffolds, without compromising the osteoblasts' proliferation and viability. In general, the obtained data support the development of 3D_rGO for being applied as temporary scaffolds supporting the new bone tissue formation and avoiding the establishment of bacterial infections.