Alginate and its application to tissue engineering

Optimizing Cu2 + adsorption prediction in Undaria pinnatifida using machine learning and isotherm models

Algae are cost-effective bioadsorbents for heavy metal remediation, yet their potential is underutilized due to limitations in traditional adsorption models. This study integrates machine learning (ML) techniques with traditional models to predict the Cu2+ adsorption capacity by Undaria pinnatifida, enabling more efficient and targeted strategies for heavy metal removal. The study determined the relationship between bioactive compounds (mannitol, alginate, phlorotannins) content in different parts (blade, stipe, sporophyll) of algae and revealed a positive correlation between phlorotannins and Cu²⁺ adsorption capacity. The adsorption behavior of algal blades was best described by the Freundlich model (R2=0.9858), pseudo-second-order kinetic model (R2=0.9989), and thermodynamic model (R2=0.9912). These models suggest multilayer adsorption and confirm the spontaneous nature of the adsorption process. ML regression using factors such as temperature, initial concentration, time, and equilibrium concentration, with CatBoost providing the best predictions (R2=0.9883). Feature importance analysis (Shapley and Partial Dependence Plot) identified the initial concentration as the most influential factor affecting Cu2+ adsorption. This study presents a novel approach by combining traditional models and ML techniques to predict algal Cu2+ adsorption capacity. The findings highlight the potential of ML for accurate predictions and provide valuable insights for enhancing the utilization of algae in environmental pollution control.

Advances in alginate-based nanoformulations: Innovative and effective strategies for targeting and treating brain disorders

Brain disorders, encompassing neurodegenerative conditions and intracranial neoplasms, present formidable obstacles in the realm of pharmacological delivery due to the existence of athe blood-brain barrier (BBB) and the restricted bioavailability of therapeutic agents. Alginate-derived nanoformulations have emerged as highly promising systems for drug delivery, offering attributes such as biocompatibility, regulated release, and improved targeting efficacies. This review investigates contemporary advancements in alginate-based nanoformulations, with a particular emphasis on their efficacy in surmounting obstacles to successful pharmacological delivery to the brain. Initially, we furnish a comprehensive overview of alginate, underscoring its pertinent properties, biomedical applications, and inherent limitations. Subsequently, the discourse progresses to strategies for nanoformulation, which encompass lipid-based, polymeric, and inorganic methodologies, with a focus on their benefits in relation to cerebral targeting. Moreover, this review entails the therapeutic potential of alginate-based nanoformulations in addressing significant neurological disorders, including Alzheimer's disease, Parkinson's disease, brain tumours, traumatic brain injury, epilepsy, and amyotrophic lateral sclerosis. By amalgamating cutting-edge nanotechnology with the distinctive properties of alginate, these formulations signify a promising pathway for the advancement of efficacious therapies aimed at brain targeting. Additionally, prospective research trajectories and challenges associated with the optimization of alginate-based nanocarriers for clinical applications are also elucidated.

Recent progress in alginate-based nanocomposites for bone tissue engineering applications

Approximately 5-10 % of fractures are associated with non-union, posing a significant challenge in orthopedic applications. Addressing this issue, innovative approaches beyond traditional grafting techniques like bone tissue engineering (BTE) are required. Biomaterials, combined with cells and bioactive molecules in BTE, are critical in managing non-union. Alginate, a natural polysaccharide, has gained widespread recognition in bone regeneration due to its bioavailability, its ability to form gels through crosslinking with divalent cations, and its cost-effectiveness. However, its inherent mechanical weaknesses necessitate a combinatorial approach with other biomaterials. In recent years, nanoscale biomaterials have gained prominence for bone regeneration due to their structural and compositional resemblance to natural bone, offering a supportive environment that regulates cell proliferation and differentiation for new bone formation. In this review, we briefly outline the synthesis of alginate-based nanocomposites using different fabrication techniques, such as hydrogels, 3D-printed scaffolds, fibers, and surface coatings with polymer, ceramic, carbon, metal, or lipid-based nanoparticles. These alginate-based nanocomposites elicit angiogenic, antibacterial, and immunomodulatory properties, thereby enhancing the osteogenic potential as an insightful measure for treating non-union. Despite the existence of similar literature, this work delivers a recent and focused examination of the latest advancements and insights on the potential of alginate-based nanocomposites for BTE applications. This review also underscores the obstacles that alginate-based nanocomposites must overcome to successfully transition into clinical applications.

Core-Shell Hydrogels with Tunable Stiffness for Breast Cancer Tissue Modelling in an Organ-on-Chip System

Breast cancer remains the most common malignancy in women, yet, many patients fail to achieve full remission despite significant advancements. This is largely due to tumour heterogeneity and the limitations of current experimental models in accurately replicating the complexity of in vivo tumour environment. In this study, we present a compartmentalised alginate hydrogel platform as an innovative in vitro tool for three-dimensional breast cancer cell culture. To mimic the heterogeneity of tumour tissues, we developed a core-shell structure (3.5% alginate core and 2% alginate shell) that mimic the stiffer, denser internal tumour matrix. The human triple-negative breast cancer cell line (MDA-MB-231) was embedded in core-shell alginate gels to assess viability, proliferation and hypoxic activity. Over one week, good cells proliferation and viability was observed, especially in the softer shell. Interestingly, cells within the stiffer core were more positive to hypoxic marker expression (HIF-1α) than those embedded in the shell, confirming the presence of a hypoxic niche, as observed in vivo. When cultured in the MIVO® milli fluidic organ-on-chip resembling the physiological fluid flow conditions, cancer cells viability became comparable between core and shell hydrogel area, emphasising the importance of the fluid flow in nutrients diffusion within three-dimensional matrixes. Cisplatin chemotherapy treatment further highlighted these differences: under static conditions, cancer cell death was prominent in the softer shell, whereas cells in the stiffer core remained resistant to cisplatin. Conversely, drug diffusion was more homogeneous in the core-shell structured treated in the organ-on-chip, leading to a uniform reduction in cell viability. These findings suggest that integrating a compartmentalised core-shell cell laden alginate model with the millifluidic organ on chip offers a more physiologically relevant experimental approach to deepening cancer cell behaviour and drug response.

Recent Advances in Alginate Lyase Engineering for Efficient Conversion of Alginate to Value-Added Products

Alginate lyases depolymerize alginate and generate alginate oligosaccharides (AOS) and eventually 4-deoxy-L-erythro-5-hexoseulose uronate (DEH), a monosaccharide. Recently, alginate lyases have garnered significant attention due to the increasing demand for AOS, which exhibit bioactivities beneficial to human health, livestock productivity, and agricultural efficiency. Additionally, these enzymes play a crucial role in producing DEH, essential in alginate catabolism in bacteria. This review explains the industrial value of AOS and DEH, which contribute broadly to industries ranging from the food industry to biorefinery processes. This review also highlights recent advances in alginate lyase applications and engineering, including domain truncation, chimeric enzyme design, rational mutagenesis, and directed evolution. These approaches have enhanced enzyme performance for efficient AOS and DEH production. We also discuss current challenges and future directions toward industrial-scale bioconversion of alginate-rich biomass.

A shift from synthetic to bio-based polymer for functionalization of textile materials: A review

Textiles are used in various wearable and technical applications, requiring diverse properties. Functionalization refers to processes that impart new properties, such as flame retardancy, anti-microbial effects, UV protection, and hydrophobicity. The textile industry is shifting from synthetic polymers to eco-friendly biopolymers, which offer biodegradability and sustainability, reducing environmental impact. Biopolymer-based finishes improve performance while being safer and greener, supporting global sustainability goals. This review focuses on biopolymers used for textile functionalization and their potential in advanced medical applications like drug delivery and tissue engineering. Common biopolymer sources include renewable resources such as plants, microorganisms, and animals. Notable biopolymers, like bacterial and plant-based nanocellulose, lignin, chitosan, alginate, gelatin, collagen, keratin, and polylactic acid (PLA), are used for functions like anti-microbial, flame retardant, UV protective, and antioxidant properties. These biopolymers are also applied in tissue engineering, drug delivery, wound healing, and cosmetics as eco-friendly, biodegradable alternatives to petroleum-based materials.

Rational Design Strategy to Improve the Thermal Stability of Alginate Lyase Pedsa0632

Alginate can be degraded by alginate lyase to produce alginate oligosaccharides (AOs). AOs are widely used in the food, agricultural, and pharmaceutical industries due to their various physiological activities. In this work, alginate lyase Pedsa0632 was successfully characterized, which exists in solution as monomers and oligomers. Pedsa0632 has poor thermal stability, displaying a half-life (t1/2, 55 °C) of merely 6.54 min at its optimum temperature. We attempted to improve the thermal stability of Pedsa0632 by changing the interface and increasing the content of the oligomers. A mutant library was generated through combinatorial engineering of disulfide bonds, intersubunit salt bridges, and PROSS (Protein Repair One-Stop Shop) guided stabilization strategies. Mutant L324 V-D353 V-M363T-T385 V (M3) was finally constructed. The wild-type (WT) enzyme was basically inactivated after 30 min of incubation at 55 °C, whereas M3 still maintained 60% relative activity after 11,000 min of incubation under the same conditions. Further structural comparisons between the WT and M3 revealed that the extraordinary stability of the M3 could be due to the mutation that induced a more stable and compact interface of Pedsa0632, resulting in an increased proportion of oligomer content. The rational design strategy used in this study can effectively improve the enzyme's thermal stability, especially oligomeric enzymes.

Alginate gels: Chemistry, gelation mechanisms, and therapeutic applications with a focus on GERD treatment

Alginate, a natural polysaccharide derived primarily from marine algae, has become popular in biomedical research due to its versatile gelation properties and biocompatibility. This review explores the chemistry, gelation mechanisms, and therapeutic applications of alginate gels, with a particular focus on their role in gastroesophageal reflux disease (GERD) management. Alginate's structure, comprised of guluronic and mannuronic acid blocks, allows for gel formation by ionic cross-linking with divalent cations like calcium ions, generating a stable "egg-box" structure. The effects of pH, temperature, and ion concentration on gelation are explored, as well as other gel forms such as in situ and heat-sensitive gels. Alginate is widely used in the medical and pharmaceutical areas to promote tissue engineering through cell encapsulation and scaffolding, as well as in drug delivery systems for controlled and targeted release. In GERD therapy, alginate produces a gel raft that inhibits acid reflux, providing an effective alternative to proton pump inhibitors. Alginate-based products have demonstrated clinical success, strengthening alginate's medicinal promise. The review also discusses alginate-related issues, such as source variability and stability, as well as innovative modifications to improve treatment effects. These improvements establish alginate as a potential material for customized medication and tailored delivery systems.

A Novel 3D Bioprinting Crosslinking Method Based on Solenoid Valve Control

The crosslinking method of bioinks is essential for scaffold formation in 3D bioprinting. Currently, the crosslinking process of bioinks presents challenges in control, resulting in diminished stability and reliability of the gel and the presence of residual crosslinking agents that may adversely affect cell viability within the gel. This study utilizes sodium alginate as the printing ink and calcium chloride as the crosslinking agent, employing a dual-mode 3D bioprinter for alternating printing. A crosslinking agent is injected through a solenoid valve after using an extrusion-based printing method to create multilayer cell scaffolds. By controlling the printing intervals and opening times of the valve, precise localized crosslinking is achieved, and multiple alternating prints can be performed according to the required thickness of the scaffold. The results indicate that this solenoid valve crosslinking technology significantly enhances the stability and biological properties of the scaffolds, including excellent hydrophilicity, decreased swelling rate, slow degradation rate, and improved mechanical properties. Additionally, due to the reduced residual crosslinking agent, the cell proliferation rate has significantly increased. This technology advances 3D bioprinting toward a more mature stage and provides significant implications for the development of dual-mode printing.

Current Utilization of Gel-Based Scaffolds and Templates in Foot and Ankle Surgery-A Review

As tissue engineering and regenerative medicine (TERM) continues to revolutionize medicine and surgery, there is also growing interest in applying these advancements to foot and ankle surgery. The purpose of this article is to provide a comprehensive review of the types of gel scaffolds and templates, their applications in foot and ankle surgery, the challenges with current utilization, and the future directions of TERM in foot and ankle surgery. With multiple compelling scaffold prospects across the numerous natural, synthetic, and hybrid polymers currently utilized in TERM, promising results have been described in the treatment of osteoarthritis (OA) and osteochondral lesions (OCLs). However, concerns with material biocompatibility, structural integrity, feasibility during surgery, and degradation still exist and limit the extent of utilization. As researchers continue to develop enhanced polymers and formulations that address current issues, there are many opportunities to increase applications across foot and ankle surgery.

Wound healing by enhancing cell proliferation: a thermoreversible formulation containing raloxifene

The challenge of ineffective wound healing, leading to chronic conditions necessitates the development of novel therapeutics strategies. Currently, a plethora of ailments have been researched and marketed globally to accelerate angiogenesis, re-epithelization, collagen synthesis, and proliferation. However, clinical translation remains challenging and requires rigorous pre- and post-clinical screening. Here, we have developed a formulation encapsulating Raloxifene, a repurposed drug, aimed to induce accelerated wound healing. Four different formulations (Forms 1, 2, 3, and 4) incorporating alginate, poloxamer 407 (P407), LiCl, and fetal bovine serum were prepared. Formulations were characterized by scanning electron microscopy, Fourier Transformation infrared spectroscopy, and rheology. In vitro assessments encompassing cell viability, cell migration, and drug release profile were conducted, subsequently, the in vivo wound healing potential was evaluated in Sprague Dawley (SD) rats. In results, we observed significant (p-value<0.05) wound healing by Form 3 at  14th due to up-regulation of TGFꞵ, Col-I and GSK3β genes. The histology results showed complete development of epidermis, endoderm and collagen fibers by Form 3, leading to complete healing. This formulation shows promise for clinical application in accelerated wound healing processes.

The Controlled Release of Platelet-Rich Plasma-Loaded Alginate Repairs Muscle Damage With Less Fibrosis

BACKGROUND

Muscle injuries often result in dysfunctional muscle repair and reduced muscle strength. While platelet-rich plasma (PRP) has emerged as a new treatment option in orthopaedics, its use for muscle injuries remains controversial.

HYPOTHESIS

Encapsulating PRP within alginate hydrogels will achieve a localized and sustained release of growth factors at the site of the muscle injury, thereby enhancing skeletal muscle repair and reducing fibrosis.

STUDY DESIGN

Controlled laboratory study.

METHODS

Bimodal blends of hydrogels were formulated using 1% oxidized high- and low-molecular weight alginate. There were 2 types of PRP prepared: leukocyte-rich PRP (L-PRP) and pure PRP (P-PRP). These PRP types were loaded onto 75L25H alginate hydrogels, and the release of TGF-β1 was quantified over time. A laceration injury was induced in mice, which was then treated with various agents: alginate only, L-PRP, L-PRP-loaded alginate (L-PRPA), P-PRP, and P-PRP-loaded alginate (P-PRPA). An additional 2 groups were formed: injury with no treatment and control with no treatment or injury.

RESULTS

Our in vitro experiments showed that after an initial burst, TGF-β1 was released in a sustained manner for approximately 1 week after the encapsulation of both PRP preparations. The in vivo experiments showed that the groups treated with bolus injections of L-PRP or P-PRP did not show significant changes in the fibrotic area. However, the L-PRPA and P-PRPA groups demonstrated a 50% reduction in the fibrotic area (P < .05), resulting in a higher ratio of regenerating myofibers and higher levels of myogenic markers (myogenin and MyHC-emb) compared with all the other groups (P < .05). The L-PRPA group demonstrated significantly improved performance on the rotarod test; interestingly, this group also had more type I collagen than type III collagen.

CONCLUSION

The administration of L-PRP and P-PRP after a muscle injury did not reduce fibrosis. However, when loaded onto alginate hydrogels, they led to benefits, resulting in a smaller area of fibrosis and greater tissue regeneration.

CLINICAL RELEVANCE

The encapsulation of different preparations of PRP by alginate hydrogels was more effective in treating muscle lacerations than injections of PRP alone. This information is relevant for future clinical studies of PRP.

Stimuli-responsive delivery systems using carbohydrate polymers: A review

Carbohydrate polymers, including Chitosan, Cellulose, Starch, Dextran, Pectin, Alginate, and Hyaluronic Acid, have been considered as stimuli-responsive biopolymers demonstrating significant potential for drug delivery approaches. Relying on the specific design and fabrication, such biopolymers are able to respond to fluctuations in pH, temperature, or enzymatic activity. This review investigates stimuli-responsive biopolymers, known as carbohydrate polymers, mainly chitosan, cellulose, and alginate, utilized as drug delivery approaches, emphasizing that these stimuli-responsive biopolymers accelerate controlled drug release. The pH-responsive delivery systems selectively target acidic tumor microenvironments, while temperature-responsive materials provide precise control for drug release produced by hyperthermia. Light-responsive biopolymers provide spatial and temporal control, providing appropriate for targeted therapy. Redox-responsive structures are especially efficient in responding to elevated glutathione (GSH) in tumor microenvironment, facilitating targeted drug release. Electro- and magnetic-responsive systems provide remote control functionalities, improving the accuracy of drug administration. The incorporation of multi-stimuli-responsive mechanisms implies a remarkable progression in drug delivery, providing a more versatile and adaptable framework for therapeutic applications. Accordingly, the future research on carbohydrate polymer-based stimuli-responsive delivery systems should focus on improving the responsiveness and targeting efficacy through complicated optimization of features and performance of carbohydrate polymers, where the integration of multifunctional moieties facilitates transformation of targeted drugs for broader biological functions.

Influence of alginate extraction conditions from the brown seaweed Dictyota mertensii on the functional properties of a novel glycerol plasticized alginate film

Alginate films were prepared from the brown seaweed Dictyota mertensii using glycerol as a plasticizer. The effects of extraction conditions-time, temperature, and Na2CO3 concentration-on the optical, barrier, and mechanical properties of the films were investigated using a central composite design (CCD). ANOVA and F tests confirmed the models' statistical significance at p ≤ 0.05, 95 % CI. Na2CO3 concentration significantly influenced moisture absorption, water vapor permeability, solubility, opacity, L*, b*, and elongation at break. Temperature mainly affected the color parameter a* and tensile strength, while time was more relevant for the modulus of elasticity. The properties of alginate from Dictyota mertensii were correlated to the film properties. Optimization through numerical desirability function yielded a global desirability index of 0.767, with optimal conditions at 1.390 h, 54.927 °C, and 0.361 mol.L-1 Na2CO3. Under these conditions, the films showed low moisture content (0.277 %), moderate WVP (31.278 g.mm/kPa.m2.h), low solubility (18.825 %), appropriate color parameters (Opacity: 12.411 AU.nm/mm, L*: 49.655, a*: 17.680, b*: 44.657), and balanced mechanical properties (TS: 13.270 MPa, EB: 20.638 %, and E: 64.592 MPa). These findings emphasize the potential of alginate films from Dictyota mertensii and promote sustainable use of marine resources.

The biotechnological and economic potential of macroalgae in the Baltic Sea

MAIN CONCLUSION

Baltic Sea macroalgae exhibit unique bioactive compounds and diverse applications, supporting sustainable industries in food, cosmetics, and medicine while promoting environmental restoration. Common in the Baltic Sea, macroalgae hold great biotechnological and commercial promise in various industries, such as food, cosmetics, and medicines. The present study investigates the various uses of the Baltic macroalgae, emphasizing their nutritional worth, which encompasses vital amino acids, vitamins, and minerals, as well as their suitability as natural gelling agents, food additives, and dietary supplements. Additionally, these macroalgae's bioactive chemicals show promise as therapeutic agents due to their antiviral and anticancer capabilities, making them essential assets for the pharmaceutical and medical sectors. A lot of research has been done on macroalgae, but not much on Baltic species. With an emphasis on their unique qualities and possible benefits to environmental preservation and sustainability, this paper attempts to present a thorough review of the uses of the Baltic macroalgae.

Aleem M, Gao H, Eissa NG, Elghamry I, Salim SA. Recent Progress of Polymer-Based Biosensors for Cancer Diagnostic Applications: Natural versus Synthetic Polymers

Early diagnosis of cancer can significantly contribute to improving therapeutic outcomes and enhancing survival rates for cancer patients. Polymer-based biosensors have emerged as a promising tool for cancer detection due to their high sensitivity, selectivity, and low cost. These biosensors utilize functionalized polymers in different parts of the body to detect cancer biomarkers in biological samples. This approach offers several advantages over traditional detection methods, including real-time monitoring and noninvasive detection while maintaining high sensitivity and accuracy. This review discusses recent advances in the development of polymer-based biosensors for cancer detection including their design, fabrication, and performance. The essential characteristics of biosensing devices are presented, along with examples for natural and synthetic polymers commonly utilized in biosensors. Furthermore, strategies employed to tailor polymers to improve biosensing applications and future perspectives for the application of polymer-based biosensors in cancer diagnosis are also highlighted. Integrating these advancements will illuminate the potential of polymer-based biosensors as transformative tools in the early detection and management of cancer.

A recent study of natural hydrogels: improving mechanical properties for biomedical applications

Natural polymer-based hydrogels, generally composed of hydrophilic polymers capable of absorbing large amounts of water, have garnered attention for biomedical applications because of their biocompatibility, biodegradability, and eco-friendliness. Natural polymer-based hydrogels derived from alginate, starch, cellulose, and chitosan are particularly valuable in fields such as drug delivery, wound dressing, and tissue engineering. However, compared with synthetic hydrogels, their poor mechanical properties limit their use in load-bearing applications. This review explores recent advancements in the enhancement of the mechanical strength of natural hydrogels while maintaining their biocompatibility for biomedical applications. Strategies such as chemical modification, blending with stronger materials, and optimized cross-linking are discussed. By improving their mechanical resilience, natural hydrogels can become more suitable for demanding biomedical applications, like tissue scaffolding and cartilage repair. Additionally, this review identifies the ongoing challenges and future directions for maximizing the potential of natural polymer-based hydrogels in advanced medical therapies.

Infertility treatment using polysaccharides-based hydrogels: new strategies in tissue engineering and regenerative medicine

Infertility is a primary health issue affecting about 15% of couples of reproductive ages worldwide, leading to physical, mental, and social challenges. Advances in nanobiotechnology and regenerative medicine are opening new therapeutic horizons for infertility by developing polysaccharide-based nanostructured biomaterials. This review explores the role of tissue engineering and regenerative medicine in infertility treatment, explicitly focusing on the promising potential of polysaccharide-based hydrogels. In this context, using these biomaterials offers unique advantages, including biodegradability, biocompatibility, and the ability to mimic the natural endometrial microenvironment, making them highly effective for applications in endometrial regeneration, ovarian tissue engineering, spermatogenesis support, and controlled drug delivery. This review discusses the various properties and uses of polysaccharide-based hydrogels, like alginate, hyaluronic acid, and chitosan, in helping to restore reproductive function. While these materials hold great promise, some notable challenges to their clinical use include issues like rapid degradation, mechanical instability, and potential immune reactions. Future research should focus on developing hybrid hydrogels, investigating advanced fabrication techniques, and testing these materials in clinical settings. By combining findings from recent studies, this review aims to provide a solid foundation for researchers and clinicians looking to discover new and effective strategies for treating infertility, ultimately connecting research efforts with practical applications in healthcare.

Electrospun Polycaprolactone-Gelatin Fibrils Enabled 3D Hydrogel Microcapsules for Biomedical Applications

Microcapsules provide a microenvironment by improving the protection and delivery of cells and drugs to specific tissue areas, promoting cell integration and tissue regeneration. Effective microcapsules must not only be permeable for micronutrient diffusion but mechanically stable. Alginate hydrogel is one of the commonly used biomaterials for fabricating microcapsules due to its gel-forming ability and low toxicity. However, its mechanical instability, inertness, and excessive porosity have impeded its use. Embedding nanofibrils in the alginate hydrogel microcapsules improves their biological and mechanical properties. In this research, electrospun composite nanofibers of PCL-gelatin (PG) were first fabricated, characterized, and cryoground. The filtered and cryoground powder solution was mixed with the alginate solution and through electrospray, fabricated into microcapsules. Parameters such as flow rate, voltage, and hydrogel composition, which are critical in the electrostatic encapsulation process, were optimized. The microcapsules were further immersed in different solvent environments (DI water, complete media, and PBS), which were observed and compared for their morphology, size distribution, and mechanical stability properties. The average diameters of the PG nanofibers ranged between 0.2 and 2 μm, with an average porosity between 58 and 73%. The average size of the microcapsules varied between 300 and 900 μm, depending on the solvent environment. Overall, results showed an improved alginate 3D hydrogel network suitable for biomedical applications.

A review of recent progress in alginate-based nanocomposite materials for tissue engineering applications

Integrating nanotechnology with tissue engineering has revolutionized biomedical sciences, enabling the development of advanced therapeutic strategies. Tissue engineering applications widely utilize alginate due to its biocompatibility, mild gelation conditions, and ease of modification. Combining different nanomaterials with alginate matrices enhances the resulting nanocomposites' physicochemical properties, such as mechanical, electrical, and biological properties, as well as their surface area-to-volume ratio, offering significant potential for tissue engineering applications. This review thoroughly overviews various nanomaterials, such as metal and metal oxide nanoparticles, carbon-based nanomaterials, MXenes, and hydroxyapatite, that modify alginate-based nanocomposites. It covers multiple preparation techniques, including layer-by-layer assembly, blending, 3D printing, and in situ synthesis. These techniques apply to tissue engineering applications, including bone tissue engineering, cardiac tissue engineering, neural tissue engineering, wound healing, and skin regeneration. Additionally, it highlights current advancements, challenges, and future perspectives.

Seaweed-derived laminarin and alginate as potential chemotherapeutical agents: An updated comprehensive review considering cancer treatment

Seaweed-derived bioactive substances such as polysaccharides have proven to be effective chemotherapeutic and chemopreventive agents. Laminarin and alginate antioxidant properties aid in the prevention of cancer through dynamic modulation of critical intracellular signaling pathways via apoptosis which produce low cytotoxicity and potential chemotherapeutic effects. Understanding the effects of laminarin and alginate on human cancer cells and their molecular roles in cell death pathways can help to develop a novel chemoprevention strategy. This review emphasizes the importance of apoptosis-modulating laminarin and alginate in a range of malignancies as well as their extraction, molecular structure, and weight. In addition, future nano-formulation enhancements for greater clinical efficacy are discussed. Laminarin and alginate are perfect ingredients because of their distinct physicochemical and biological characteristics and their use-based delivery systems in cancer. The effectiveness of laminarin and alginate against cancer and more preclinical and clinical trials will open up as new chemotherapeutic natural drugs which lead to established as potential cancer drugs.

Recent developments in alginate-based nanocomposite coatings and films for biodegradable food packaging applications

Packaging made of plastic harms the environment. Thus, polysaccharide edible films are becoming a popular food packaging solution. Alginate is a biopolymer derived from seaweed that has the potential to create food packaging materials that are environmentally friendly and biodegradable. This article explores the potential use of nanocomposite coatings and films made from alginate as an alternative to petroleum-based polymers in the food industry. Alginate is desirable for food packaging due to its low cost, high nutritional value, renewability, low oxygen permeability, biodegradability, and biocompatibility. This article delves into alginate's history and extraction processes and covers techniques for modifying its physical and chemical properties using blended polymers and additives. Alginate-based coatings and films have been found to improve the mechanical properties and sensory characteristics of various food items and prolong the shelf life of perishable items by regulating oxygen and moisture levels and as a barrier against microbial growth. Further investigation is necessary to maximize the performance of alginate-based polymers in various food industry applications. Future prospects call on advancements in their physicochemical and functional characteristics to increase the acceptability of alginate-based nanocomposite coatings and films for biodegradable food packaging applications.

Next-Generation Biomaterials for Vital Pulp Therapy: Exploring Biological Properties and Dentin Regeneration Mechanisms

The advancement of Vital Pulp Therapy (VPT) in dentistry has shown remarkable progress, with a focus on innovative materials and scaffolds to facilitate reparative dentin formation and tissue regeneration. A comprehensive search strategy was performed across PubMed, Scopus, and Web of Science using keywords such as "vital pulp therapy", "biomaterials", "dentin regeneration", and "growth factors", with filters for English language studies published in the last 10 years. The inclusion criteria focused on in vitro, in vivo, and clinical studies evaluating traditional and next-generation biomaterials for pulp capping and tissue regeneration. Due to the limitations of calcium-based cements in tissue regeneration, next-generation biomaterials like gelatin, chitosan, alginate, platelet-rich fibrins (PRF), demineralized dentin matrix (DDM), self-assembling peptides, and DNA-based nanomaterials were explored for their enhanced biocompatibility, antibacterial properties, and regenerative potential. These biomaterials hold great potential in enhancing VPT outcomes, but further research is required to understand their efficacy and impact on dentin reparative properties. This review explores the mechanisms and properties of biomaterials in dentin tissue regeneration, emphasizing key features that enhance tissue regeneration. These features include biomaterial sources, physicochemical properties, and biological characteristics that support cells and functions. The discussion also covers the biomaterials' capability to encapsulate growth factors for dentin repair. The development of innovative biomaterials and next-generation scaffold materials presents exciting opportunities for advancing VPT in dentistry, with the potential to improve clinical outcomes and promote tissue regeneration in a safe and effective manner.

Advanced biomaterials in pressure ulcer prevention and care: from basic research to clinical practice

Pressure ulcers are a common and serious medical condition. Conventional treatment methods often fall short in addressing the complexities of prevention and care. This paper provides a comprehensive review of recent advancements in advanced biomaterials for pressure ulcer management, emphasizing their potential to overcome these limitations. The study highlights the roles of biomaterials in enhancing wound healing, preventing infections, and accelerating recovery. Specific focus is placed on the innovation and application of multi-functional composite materials, intelligent systems, and personalized solutions. Future research should prioritize interdisciplinary collaboration to facilitate the clinical translation of these materials, providing more effective and tailored treatment approaches. These advancements aim to improve the quality of life and health outcomes for patients by offering more reliable, efficient, and patient-specific therapeutic options.

Nanomaterial-functionalized electrospun scaffolds for tissue engineering

Tissue engineering has emerged as a biological alternative aimed at sustaining, rehabilitating, or enhancing the functionality of tissues that have experienced partial or complete loss of their operational capabilities. The distinctive characteristics of electrospun nanofibrous structures, such as their elevated surface-area-to-volume ratio, specific pore sizes, and fine fiber diameters, make them suitable as effective scaffolds in tissue engineering, capable of mimicking the functions of the targeted tissue. However, electrospun nanofibers, whether derived from natural or synthetic polymers or their combinations, often fall short of replicating the multifunctional attributes of the extracellular matrix (ECM). To address this, nanomaterials (NMs) are integrated into the electrospun polymeric matrix through various functionalization techniques to enhance their multifunctional properties. Incorporation of NMs into electrospun nanofibrous scaffolds imparts unique features, including a high surface area, superior mechanical properties, compositional variety, structural adaptability, exceptional porosity, and enhanced capabilities for promoting cell migration and proliferation. This review provides a comprehensive overview of the various types of NMs, the methodologies used for their integration into electrospun nanofibrous scaffolds, and the recent advancements in NM-functionalized electrospun nanofibrous scaffolds aimed at regenerating bone, cardiac, cartilage, nerve, and vascular tissues. Moreover, the main challenges, limitations, and prospects in electrospun nanofibrous scaffolds are elaborated.

Platelet-Rich Plasma Loaded Alginate-Based Injectable Hydrogel for Meniscal Tear Repair: In Vivo Evaluation in Lapine Model

Platelet-rich plasma (PRP) has been employed for orthopedic applications for decades due to the abundance of bioactive cues/growth factors that ameliorate the proliferation and migration of relevant cells involved in tissue repair/regeneration. In this work, PRP was incorporated into injectable compositions of alginate-based hydrogel and evaluated in vitro and in vivo. In vitro tests revealed that PRP addition promoted cell adhesion, cell proliferation, and distribution of seeded fibrochondrocytes on the hydrogel. Further, the DNA quantification and sGAG estimation confirmed the production of fibrocartilage-specific extracellular matrix, predominantly type 1 collagen and sGAG. For in vivo evaluation, tears were created surgically in the rabbit menisci and were filled with injectable hydrogel. Sham and hydrogel without PRP were used as controls. Histopathological evaluation after 3 months of implantation revealed that the healing was partial for sham control, but complete for hydrogel without PRP. The hydrogel served as the scaffold for fibrocartilage tissue regeneration. On the other hand, PRP-incorporated hydrogel showed good healing with low signs of inflammation as evidenced by histology and biochemical content. The healing was complete, and the nature of the regenerated tissues was very close to native tissue indicating that alginate-based hydrogel is a promising candidate for meniscal tissue repair.

Alginate-based microencapsulation as a strategy to improve the therapeutic potential of cannabidiolic acid

Cannabidiolic Acid (CBDA) is a promising natural compound with potent antioxidant, anti-inflammatory, and anti-emetic properties. Its antioxidant activity rivals that of vitamin E, while its anti-inflammatory effects are also remarkable. Additionally, CBDA has been shown to effectively reduce nausea and emetic attacks. As a more natural and water-soluble alternative to CBD, CBDA offers improved bioavailability and absorption. However, despite its promising potential, the development of effective CBDA delivery systems is still in its early stages. Among the various materials suitable for drug delivery, alginate is a widely used biopolymer due to its abundance and common availability in nature. This study aimed to develop an efficient CBDA delivery carrier using a microflow-dripping method to microencapsulate CBDA into alginate carriers (Alg-CBDA). The antioxidant, antimicrobial, and cytotoxicity properties of these Alg-CBDA capsules were then evaluated. Our results demonstrated that encapsulating CBDA within alginate capsules yielded a novel multifunctional biomaterial with prolonged antioxidant activity up to 72 h and antimicrobial activity against Gram-positive bacteria. Furthermore, the encapsulation process significantly reduced CBDA's cytotoxicity, broadening its potential applications. To our knowledge, this is the first study demonstrating the advantages of CBDA within a drug delivery framework.

Sacrificing Alginate in Decellularized Extracellular Matrix Scaffolds for Implantable Artificial Livers

This research introduced a strategy to fabricate sub-millimeter-diameter artificial liver tissue by extruding a combination of a liver decellularized extracellular matrix (dECM), alginate, endothelial cells, and hepatocytes. Vascularization remains a critical challenge in liver tissue engineering, as replicating the liver's intricate vascular network is essential for sustaining cellular function and viability. Seven scaffold groups were evaluated, incorporating different cell compositions, scaffold materials, and structural configurations. The hepatocyte and endothelial cell scaffold treated with alginate lyase demonstrated the highest diffusion rate, along with enhanced albumin secretion (2.8 µg/mL) and urea synthesis (220 µg/mL) during the same period by day 10. A dense and interconnected endothelial cell network was observed as early as day 4 in the lyased coculture group. Furthermore, three-week implantation studies in rats showed a stable integration to the host with no adverse effects. This approach offers significant potential for advancing functional liver tissue replacements, combining accelerated diffusion, enhanced albumin secretion, improved urea synthesis, dense vascular network formation, and stable implantation outcomes.

Bioprinting approaches in cardiac tissue engineering to reproduce blood-pumping heart function

The heart, with its complex structural and functional characteristics, plays a critical role in sustaining life by pumping blood throughout the entire body to supply nutrients and oxygen. Engineered heart tissues have been introduced to reproduce heart functions to understand the pathophysiological properties of the heart and to test and develop potential therapeutics. Although numerous studies have been conducted in various fields to increase the functionality of heart tissue to be similar to reality, there are still many difficulties in reproducing the blood-pumping function of the heart. In this review, we discuss advancements in cells, biomaterials, and biofabrication in cardiac tissue engineering to achieve cardiac models that closely mimic the pumping function. Moreover, we provide insight into future directions by proposing future perspectives to overcome remaining challenges, such as scaling up and biomimetic patterning of blood vessels and nerves through bioprinting.

Insight into the digestion mechanism of proteins in silver carp (Hypophthalmichthys molitrix) surimi by different alginates

This study aimed to evaluate the impact of potassium alginate (PA), propylene glycol alginate (PGA), and calcium alginate (CA) on the gel properties of silver carp (Hypophthalmichthys molitrix) surimi (control group) throughout gastrointestinal digestion. The findings revealed that the protein digestibility of the PA/PGA and CA groups was found to be lower compared to the control group. Among these groups, the CA group had the lowest digestibility rate at 82.49 ± 3.50 %. The study revealed a reduction in the number of peptides found in the surimi group treated with alginate compared to the control group. Alginate was discovered to have inhibitory effects on proteolysis by forming a robust cross-linked network that obstructs pepsin from accessing its substrates. This research provides valuable insights into the potential application of alginate for improving the digestibility of surimi proteins and creating commercial surimi products.

Polydiacetylene (PDA) Embedded Polymer-Based Network Structure for Biosensor Applications

Biosensors, which combine physical transducers with biorecognition elements, have seen significant advancement due to the heightened interest in rapid diagnostic technologies across a number of fields, including medical diagnostics, environmental monitoring, and food safety. In particular, polydiacetylene (PDA) is gaining attention as an ideal material for label-free colorimetric biosensor development due to its unique color-changing properties in response to external stimuli. PDA forms through the self-assembly of diacetylene monomers, with color change occurring as its conjugated backbone twists in response to stimuli such as temperature, pH, and chemical interactions. This color change enables the detection of biomarkers, metal ions, and toxic compounds. Moreover, the combination of PDA with polymeric structures including hydrogels further enhances the sensitivity and structural stability of PDA-based biosensors, making them reliable and effective in complex biological and environmental conditions. This review comprehensively examines recent research trends and applications of PDA-polymeric structure hybrid biosensors, while discussing future directions and potential advancements in this field.

Biological Scaffolds in 3D Cell Models: Driving Innovation in Drug Discovery

The discipline of 3D cell modeling is currently undergoing a surge of captivating developments that are enhancing the realism and utility of tissue simulations. Using bioinks which represent cells, scaffolds, and growth factors scientists can construct intricate tissue architectures layer by layer using innovations like 3D bioprinting. Drug testing can be accelerated and organ functions more precisely replicated owing to the precise control that microfluidic technologies and organ-on-chip devices offer over the cellular environment. Tissue engineering is becoming more dynamic with materials that can modify their surroundings with the advent of hydrogels and smart biomaterials. Advances in spheroids and organoids are not only bringing us towards more effective and customized therapies, but they are also improving their ability to resemble actual human tissues. Confocal and two-photon microscopy are examples of advanced imaging methods that provide precise images of the functioning and interaction of cells. Artificial Intelligence models have applications for enhanced scaffold designs and for predicting the response of tissues to medications. Furthermore, via strengthening predictive models, optimizing data analysis, and simplifying 3D cell culture design, artificial intelligence is revolutionizing this field. When combined, these technologies are improving our ability to conduct research and moving us toward more individualized and effective medical interventions.

Advancements in biomaterials and scaffold design for tendon repair and regeneration

Tendon injuries present a significant clinical challenge due to their limited natural healing capacity and the mechanical demands placed on these tissues. This review provides a comprehensive evaluation of the current strategies and advancements in tendon repair and regeneration, focusing on biomaterial innovations and scaffold design. Through a systematic literature search of databases such as PubMed, Scopus, and Web of Science, key studies were analyzed to assess the efficacy of biocompatible materials like hydrogels, synthetic polymers, and fiber-reinforced scaffolds in promoting tendon healing. Emphasis is placed on the role of collagen fiber architecture, including fiber diameter, alignment, and crimping, in restoring the mechanical strength and functional properties of tendons. Additionally, the review highlights emerging techniques such as electrospinning, melt electrowriting, and hybrid textile methods that allow for precise scaffold designs mimicking native tendon structures. Cutting-edge approaches in regenerative medicine, including stem cell therapies, bioelectronic devices, and bioactive molecules, are also explored for their potential to enhance tendon repair. The findings underscore the transformative impact of these technologies on improving tendon biomechanics and functional recovery. Future research directions are outlined, aiming to overcome the current limitations in scaffold mechanical properties and integration at tendon-bone and tendon-muscle junctions. This review contributes to the development of more effective strategies for tendon regeneration, advancing both clinical outcomes and the field of orthopedic tissue engineering.

Natrium Alginate and Graphene Nanoplatelets-Based Efficient Material for Resveratrol Delivery

In this study, alginate-based composite beads were developed for the delivery of resveratrol, a compound with therapeutic potential. Two formulations were prepared: one with sodium alginate and resveratrol (AR) and another incorporating graphene nanoplatelets (AGR) to improve drug release control. The beads were formed by exploiting alginate's ability to gel via ionic cross-linking. For the AGR formulation, sodium alginate was dissolved in water, and graphene was dispersed in isopropyl alcohol to achieve smaller flakes. Resveratrol was dissolved in an ethanol/water mixture and added to the graphene dispersion; the resulting solution was mixed with the alginate one. For the AR formulation, the resveratrol solution was mixed directly with the alginate solution. Both formulations were introduced into a calcium chloride solution to form the beads. The release of resveratrol was studied in phosphate-buffered saline at different pH values. Results showed that the presence of graphene in the AGR sample increased drug release, particularly at pH 6.8, indicating a pH-driven release mechanism. Kinetic analysis revealed that the Higuchi model best describes the release mechanism. Finally, cytotoxicity tests showed the biocompatibility of the system in normal human cells. These findings suggest that graphene-enhanced alginate matrices have significant potential for controlled drug delivery applications.

State-of-the-Art Synthesis of Porous Polymer Materials and Their Several Fantastic Biomedical Applications: a Review

Porous polymers, including hydrogels, covalent organic frameworks (COFs), and hyper crosslinked polymers (HCPs), have become essential in biomedical research for their tunable pore architectures, large surface areas, and functional versatility. This review provides a comprehensive overview of their classification and updated synthesis mechanisms, such as 3D printing, electrospinning, and molecular imprinting. Their pivotal roles in drug delivery, tissue engineering, wound healing, and photodynamic/photothermal therapies, focusing on how pore size, distribution, and architecture impact drug release, cellular interactions, and therapeutic outcomes, are explored. Key challenges, including biocompatibility, mechanical strength, controlled degradation, and scalability, are critically assessed alongside emerging strategies to enhance clinical potential. Finally, recent challenges and future perspectives, emphasizing the broader biomedical applications of porous polymers, are addressed. This work provides valuable insights for advancing next-generation biomedical innovations through these materials.

From lab to life: advances inin-situbioprinting and bioink technology

Bioprinting has the potential to revolutionize tissue engineering and regenerative medicine, offering innovative solutions for complex medical challenges and addressing unmet clinical needs. However, traditionalin vitrobioprinting techniques face significant limitations, including difficulties in fabricating and implanting scaffolds with irregular shapes, as well as limited accessibility for rapid clinical application. To overcome these challenges,in-situbioprinting has emerged as a groundbreaking approach that enables the direct deposition of cells, biomaterials, and bioactive factors onto damaged organs or tissues, eliminating the need for pre-fabricated 3D constructs. This method promises a personalized, patient-specific approach to treatment, aligning well with the principles of precision medicine. The success ofin-situbioprinting largely depends on the advancement of bioinks, which are essential for maintaining cell viability and supporting tissue development. Recent innovations in hand-held bioprinting devices and robotic arms have further enhanced the flexibility ofin-situbioprinting, making it applicable to various tissue types, such as skin, hair, muscle, bone, cartilage, and composite tissues. This review examinesin-situbioprinting techniques, the development of smart, multifunctional bioinks, and their essential properties for promoting cell viability and tissue growth. It highlights the versatility and recent advancements inin-situbioprinting methods and their applications in regenerating a wide range of tissues and organs. Furthermore, it addresses the key challenges that must be overcome for broader clinical adoption and propose strategies to advance these technologies toward mainstream medical practice.

Processes of Obtaining Nanostructured Materialswith a Hierarchical Porous Structure on the Example of Alginate Aerogels

Currently, materials with specific, strictly defined functional properties are becoming increasingly important. A promising strategy for achieving these properties involves developing methods that facilitate the formation of hierarchical porous materials that combine micro-, meso-, and macropores in their structure. Macropores facilitate effective mass transfer of substances to the meso- and micropores, where further adsorption or reaction processes can occur. Aerogels represent a promising class of materials for implementing this approach. The formation of hierarchical porous structures in aerogels can be achieved using soft and hard templating methods or by foaming techniques. This paper presents a comprehensive study of three methods for forming hierarchical porous structures in alginate aerogels: (1) employing surfactants (Pluronic F-68), (2) using zein as a pore-forming component, and (3) foaming in a carbon dioxide medium. The results of micro-CT showed that each of the methods contributes to the formation of macropores within the structure of the resulting aerogels. Size distribution curves of the detected macropores were obtained, showing the presence of macropores ranging from 16 to 323 μm in size for samples obtained using surfactants, from 5 to 195 μm for samples obtained using zein, and from 20 μm to 3 mm for samples obtained by foaming in a carbon dioxide medium. The SEM images demonstrated the macro- and mesoporous fibrous structure of the obtained materials. The nitrogen porosimetry results indicated that samples obtained using surfactants and zein are characterized by a high specific surface area (592-673 m2/g), comparable to the specific surface area for an alginate-based aerogel obtained without the use of pore-forming components. However, the use of the developed methods for the formation of a hierarchical porous structure contributes to an increase in the specific mesopores volume (up to 17.7 cm3/g). The materials obtained by foaming in a carbon dioxide medium are characterized by lower specific surface areas (112-239 m2/g) and specific mesopores volumes (0.6-2.1 cm3/g). Thus, this paper presents a set of methods for forming hierarchical porous structures that can obtain delivery systems for active substances with a controlled release profile and highly efficient platforms for cell culturing.

In Situ Bioprinting: Process, Bioinks, and Applications

Traditional tissue engineering methods face challenges, such as fabrication, implantation of irregularly shaped scaffolds, and limited accessibility for immediate healthcare providers. In situ bioprinting, an alternate strategy, involves direct deposition of biomaterials, cells, and bioactive factors at the site, facilitating on-site fabrication of intricate tissue, which can offer a patient-specific personalized approach and align with the principles of precision medicine. It can be applied using a handled device and robotic arms to various tissues, including skin, bone, cartilage, muscle, and composite tissues. Bioinks, the critical components of bioprinting that support cell viability and tissue development, play a crucial role in the success of in situ bioprinting. This review discusses in situ bioprinting techniques, the materials used for bioinks, and their critical properties for successful applications. Finally, we discuss the challenges and future trends in accelerating in situ printing to translate this technology in a clinical settings for personalized regenerative medicine.

Electrospinning of methacrylated alginate for tissue engineering applications

Photo-crosslinkable methacrylated alginate derivatives (M-ALGs) were synthesized via modification of sodium alginate with glycidyl methacrylate. Needle (capillary) and needleless electrospinning techniques were employed to produce their nonwoven fiber mats. Spinning parameters such as applied voltage, solution composition, and flow rate were optimized to form uniform bead-free fibers with an average diameter of about 150 nm. The needleless technique allowed successful electrospinning of M-ALG solutions with wider ranges of viscosities and surface tensions owing to its higher applicable voltage (∼65 kV) compared to that of the needle technique (∼30 kV). Photo-crosslinking of the fibers via UV irradiation allowed the fiber mats to remain insoluble in physiological media while maintaining their mechanical properties. Cultivation of multipotent mesenchymal stem cells (MSCs) with the cross-linked fiber mats in a modified Eagle medium (α-MEM) showed the growth of spherical colonies, indicating the sufficient cytocompatibility of the fiber mats with MSCs.

Tunable Viscoelasticity of Alginate Hydrogels via Serial Autoclaving

Alginate hydrogels are widely used as biomaterials for cell culture and tissue engineering due to their biocompatibility and tunable mechanical properties. Reducing alginate molecular weight is an effective strategy for modulating hydrogel viscoelasticity and stress relaxation behavior, which can significantly impact cell spreading and fate. However, current methods like gamma irradiation to produce low molecular weight alginates suffer from high cost and limited accessibility. Here, a facile and cost-effective approach to reduce alginate molecular weight in a highly controlled manner using serial autoclaving is presented. Increasing the number of autoclave cycles results in proportional reductions in intrinsic viscosity, hydrodynamic radius, and molecular weight of the polymer while maintaining its chemical composition. Hydrogels fabricated from mixtures of the autoclaved alginates exhibit tunable mechanical properties, with inclusion of lower molecular weight alginate leading to softer gels with faster stress relaxation behaviors. The method is demonstrated by establishing how viscoelastic relaxation affects the spreading of encapsulated fibroblasts and glioblastoma cells. Results establish repetitive autoclaving as an easily accessible technique to generate alginates with a range of molecular weights and to control the viscoelastic properties of alginate hydrogels, and demonstrate utility across applications in mechanobiology, tissue engineering, and regenerative medicine.

Comparison of cation and anion-mediated resolution enhancement of bioprinted hydrogels for membranous tissue fabrication

Fabrication of engineered thin membranous tissues (TMTs) presents a significant challenge to researchers, as these structures are small in scale, but present complex anatomies containing multiple stratified cell layers. While numerous methodologies exist to fabricate such tissues, many are limited by poor mechanical properties, need for post-fabrication, or lack of cytocompatibility. Extrusion bioprinting can address these issues, but lacks the resolution necessary to generate biomimetic, microscale TMT structures. Therefore, our goal was to develop a strategy that enhances bioprinting resolution below its traditional limit of 150 μm and delivers a viable cell population. We have generated a system to effectively shrink printed gels via electrostatic interactions between anionic and cationic polymers. Base hydrogels are composed of gelatin methacrylate type A (cationic), or B (anionic) treated with anionic alginate, and cationic poly-L-lysine, respectively. Through a complex coacervation-like mechanism, the charges attract, causing compaction of the base GelMA network, leading to reduced sample dimensions. In this work, we evaluate the role of both base hydrogel and shrinking polymer charge on effective print resolution and cell viability. The alginate anion-mediated system demonstrated the ability to reach bioprinting resolutions of 70 μm, while maintaining a viable cell population. To our knowledge, this is the first study that has produced such significant enhancement in extrusion bioprinting capabilities, while also remaining cytocompatible.

Recent advances in polysaccharide-based drug delivery systems for cancer therapy: a comprehensive review

Cancer has a high rate of incidence and mortality throughout the world. Although several conventional approaches have been developed for the treatment of cancer, such as surgery, chemotherapy, radiotherapy and thermal therapy, they have remarkable disadvantages which result in inefficient treatment of cancer. For example, immunogenicity, prolonged treatment, non-specificity, metastasis and high cost of treatment, are considered as the major drawbacks of chemotherapy. Therefore, there is a fundamental requirement for the development of breakthrough technologies for cancer suppression. Polysaccharide-based drug delivery systems (DDSs) are the most reliable drug carriers for cancer therapy. Polysaccharides, as a kind of practical biomaterials, are divided into several types, including chitosan, alginates, dextran, hyaluronic acid, cyclodextrin, pectin, etc. Polysaccharides are extracted from different natural resources (like herbal, marine, microorganisms, etc.). The potential features of polysaccharides have made them reliable candidates for therapeutics delivery to cancer sites; the simple purification, ease of modification and functionalization, hydrophilicity, serum stability, appropriate drug loading capacity, biocompatibility, bioavailability, biodegradability and stimuli-responsive and sustained drug release manner are considerable aspects of these biopolymers. This review highlights the practical applications of polysaccharides-based DDSs in pharmaceutical science and cancer therapy.

Algal carbohydrates: Sources, biosynthetic pathway, production, and applications

Algae play a significant role in the global carbon cycle by utilizing photosynthesis to efficiently convert solar energy and atmospheric carbon dioxide into various chemical compounds, notably carbohydrates, pigments, lipids, and released oxygen, making them a unique sustainable cellular factory. Algae mostly consist of carbohydrates, which include a broad variety of structures that contribute to their distinct physical and chemical properties such as degree of polymerization, side chain, branching, degree of sulfation, hydrogen bond etc., these features play a crucial role in regulating many biological activity, nutritional and pharmaceutical properties. Algal carbohydrates have not received enough attention in spite of their distinctive structural traits linked to certain biological and physicochemical properties. Nevertheless, it is anticipated that there will be a significant increase in the near future due to increasing demand, sustainable source, biofuel generation and their bioactivity. This is facilitated by the abundance of easily accessible information on the structural data and distinctive characteristics of these biopolymers. This review delves into the different types of saccharides such as agar, alginate, fucoidan, carrageenan, ulvan, EPS and glucans synthesized by various macroalgal and microalgal systems, which include intracellular, extracellular and cell wall saccharides. Their structure, biosynthetic pathway, sources, production strategies and their applications in various field such as nutraceuticals, pharmaceuticals, biomedicine, food and feed, cosmetics, and bioenergy are also elaborately discussed. Algal polysaccharide has huge a scope for exploitation in future due to their application in food and pharmaceutical industry and it can become a huge source of capital and income.

Commercially available bioinks and state-of-the-art lab-made formulations for bone tissue engineering: A comprehensive review

Bioprinting and bioinks are two of the game changers in bone tissue engineering. This review presents different bioprinting technologies including extrusion-based, inkjet-based, laser-assisted, light-based, and hybrid technologies with their own strengths and weaknesses. This review will aid researchers in the selection and assessment of the bioink; the discussion ranges from commercially available bioinks to custom lab-made formulations mainly based on natural polymers, such as agarose, alginate, gelatin, collagen, and chitosan, designed for bone tissue engineering. The review is centered on technological advancements and increasing clinical demand within the rapidly growing bioprinting market. From this point of view, 4D, 5D, and 6D printing technologies promise a future where unprecedented levels of innovation will be involved in fabrication processes leading to more dynamic multifunctionalities of bioprinted constructs. Further advances in bioprinting technology, such as hybrid bioprinting methods are covered, with the promise to meet personalized medicine goals while advancing patient outcomes for bone tissues engineering applications.

Optimization of an Affordable and Efficient Skin Allograft Composite with Excellent Biomechanical and Biological Properties Suitable for the Regeneration of Deep Skin Wounds: A Preclinical Study

Deep skin wounds require grafting with a skin substitute for treatment. Despite many attempts in the development of an affordable and efficient skin substitute, the repair of deep skin wounds still remains challenging. In the current study, we present a 3D sponge composite made from human placenta (a disposable organ) and sodium alginate with exceptional properties for skin tissue engineering applications. Toward this goal, different proportions of alginate (Alg) and decellularized placenta scaffold (DPS) were composited and freeze-dried to generate a 3D sponge with the desired biomechanical and biological features. Comprehensive in vitro, in ovo, and in vivo characterizations were performed to assess the morphology, physical structure, mechanical behaviors, angiogenic potential, and wound healing properties of the composites. Through these analyses, the scaffold with optimal proportions of Alg (50%) and DPS (50%) was found to have superior properties. The optimized scaffold (Alg50/DPS50) was applied to the full-thickness wounds created in rats. Our data revealed that the addition of DPS to the Alg solution caused a significant improvement in the mechanical characteristics of the scaffold. Remarkably, the fabricated composite scaffold exhibited mechanical properties similar to those of native skin tissue. When implanted into the full-thickness wounds, the Alg50/DPS50 composite scaffold promoted angiogenesis, re-epithelialization, and granulation tissue formation, as compared to the group without a scaffold. Overall, our findings underscore the potential value of this hybrid scaffold for enhancing skin wound healing and suggest an Alg50/DPS50 composite for clinical investigations.

Ultrasound-Assisted Extraction of Alginate from Fucus vesiculosus Seaweed By-Product Post-Fucoidan Extraction

The solid phase byproduct obtained after conventional fucoidan extraction from the brown seaweed Fucus vesiculosus can be used as a source containing alginate. This study involves ultrasound-assisted extraction (UAE) of alginate from the byproduct using sodium bicarbonate. Response surface methodology (RSM) was applied to obtain the optimum conditions for alginate extraction. The ultrasound (US) treatments included 20 kHz of frequency, 20-91% of amplitude, and an extraction time of 6-34 min. The studied investigated the crude alginate yield (%), molecular weight, and alginate content (%) of the extracts. The optimum conditions for obtaining alginate with low molecular weight were found to be 69% US amplitude and sonication time of 30 min. The alginate extracts obtained were characterized using Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). Ultrasound-assisted extraction involving a short treatment lasting 6-34 min was found to be effective in extracting alginate from the byproduct compared to the conventional extraction of alginate using stirring at 415 rpm and 60 °C for 24 h. The US treatments did not adversely impact the alginate obtained, and the extracted alginates were found to have similar characteristics to the alginate obtained from conventional extraction and commercial sodium alginate.

Advances in 3D printing technology for preparing bone tissue engineering scaffolds from biodegradable materials

Introduction

Bone tissue engineering (BTE) provides an effective repair solution by implanting osteoblasts or stem cells into biocompatible and biodegradable scaffolds to promote bone regeneration. In recent years, the rapid development of 3D bioprinting has enabled its extensive application in fabricating BTE scaffolds. Based on three-dimensional computer models and specialized "bio-inks," this technology offers new pathways for customizing BTE scaffolds. This study reviews the current status and future prospects of scaffold materials for BTE in 3D bioprinting.

Methods

This literature review collected recent studies on BTE and 3D bioprinting, analyzing the advantages and limitations of various scaffold materials for 3D printing, including bioceramics, metals, natural polymers, and synthetic polymers. Key characteristics like biocompatibility, mechanical properties, and degradation rates of these materials were systematically compared.

Results

The study highlights the diverse performances of materials used in BTE scaffolds. Bioceramics exhibit excellent biocompatibility but suffer from brittleness; metals offer high strength but may induce chronic inflammation; natural polymers are biocompatible yet have poor mechanical properties, while synthetic polymers offer strong tunability but may produce acidic by-products during degradation. Additionally, integrating 3D bioprinting with composite materials could enhance scaffold biocompatibility and mechanical properties, presenting viable solutions to current challenges.

Discussion

This review summarizes recent advances in 3D bioprinting for BTE scaffold applications, exploring the strengths and limitations of various materials and proposing composite material combinations to improve scaffold performance. By optimizing material selection and combinations, 3D bioprinting shows promise for creating customized scaffolds, offering a new technical route for clinical applications of BTE. This research provides a unique perspective and theoretical support for advancing 3D bioprinting technology in bone regeneration, outlining future directions for BTE materials and 3D bioprinting technology development.

Cysteine Conjugation: An Approach to Obtain Polymers with Enhanced Muco- and Tissue Adhesion

The modification of polymers towards increasing their biocompatibility gathers the attention of scientists worldwide. Several strategies are used in this field, among which chemical post-polymerization modification has recently been the most explored. Particular attention revolves around polymer-L-cysteine (Cys) conjugates. Cys, a natural amino acid, contains reactive thiol, amine, and carboxyl moieties, allowing hydrogen bond formation and improved tissue adhesion when conjugated to polymers. Conjugation of Cys and its derivatives to polymers has been examined mostly for hyaluronic acid, chitosan, alginate, polyesters, polyurethanes, poly(ethylene glycol), poly(acrylic acid), polycarbophil, and carboxymethyl cellulose. It was shown that the conjugation of Cys and its derivatives to polymers significantly increased their tissue adhesion, particularly mucoadhesion, stability at physiological pH, drug encapsulation efficiency, drug release, and drug permeation. Conjugates were also non-toxic toward various cell lines. These properties make Cys conjugation a promising strategy for advancing polymer applications in drug delivery systems and tissue engineering. This review aims to provide an overview of these features and to present the conjugation of Cys and its derivatives as a modern and promising approach for enhancing polymer tissue adhesion and its application in the medical field.

Alginate Formulation for Wound Healing Applications

Significance: Alginate, sourced from seaweed, holds significant importance in industrial and biomedical domains due to its versatile properties. Its chemical composition, primarily comprising β-D-mannuronic acid and α-L-guluronic acid, governs its physical and biological attributes. This polysaccharide, extracted from brown algae and bacteria, offers diverse compositions impacting key factors such as molecular weight, flexibility, solubility, and stability. Recent Advances: Commercial extraction methods yield soluble sodium alginate essential for various biomedical applications. Extraction processes involve chemical treatments converting insoluble alginic acid salts into soluble forms. While biosynthesis pathways in bacteria and algae share similarities, differences in enzyme utilization and product characteristics are noted. Critical Issues: Despite its widespread applicability, challenges persist regarding alginate's stability, biodegradability, and bioactivity. Further understanding of its interactions in complex biological environments and the optimization of extraction and synthesis processes are imperative. Additionally, concerns regarding immune responses to alginate-based implants necessitate thorough investigation. Future Directions: Future research endeavors aim to enhance alginate's stability and bioactivity, facilitating its broader utilization in regenerative medicine and therapeutic interventions. Novel approaches focusing on tailored hydrogel formations, advanced drug delivery systems, and optimized cellular encapsulation techniques hold promise. Continued exploration of alginate's potential in tissue engineering and wound healing, alongside efforts to address critical issues, will drive advancements in biomedical applications.

Synthesis of agro-industrial wastes/sodium alginate/bovine gelatin-based polysaccharide hydrogel beads: Characterization and application as controlled-release microencapsulated fertilizers

Synthesis of novel agro-industrial wastes/sodium alginate/bovine gelatin-based polysaccharide hydrogel beads, micromeritic/morphometric characteristics of the prepared formulations, greenhouse trials using controlled-release microencapsulated fertilizers, and acute fish toxicity testing were conducted simultaneously for the first time within the scope of an integrated research. In the present analysis, for the first time, 16 different morphometric features, and 32 disinct plant growth traits of the prepared composite beads were explored in detail within the framework of a comprehensive digital image analysis. The hydrogel beads composed of 19 different agro-industrial wastes/materials were successfully synthesized using the ionotropic external gelation technique and CaCl2 as cross-linker. According to micromeritic characteristics, the ionotropically cross-linked beads exhibited 77.86 ± 3.55 % yield percentage and 2.679 ± 0.397 mm average particle size. The dried microbeads showed a good swelling ratio (270.02 ± 80.53 %) and had acceptable flow properties according to Hausner's ratio (1.136 ± 0.028), Carr's index (11.94 ± 2.17 %), and angle of repose (25.03° ± 5.33°) values. The settling process of the prepared microbeads was observed in the intermediate flow regime, as indicated by the average particle Reynolds numbers (169.17 ± 82.81). Experimental findings and non-parametric statistical tests reveal that dried fertilizer matrices demonstrated noteworthy performance on the cultivation of red hot chili pepper plant (Capsicum annuum var. fasciculatum) according to the results of greenhouse trials. Surface morphologies of the best-performing fertilizer matrices were also characterized by Scanning Electron Microscopy. Moreover, the static fish bioassay experiment confirmed that no abnormalities and acute toxic reactions occurred in shortfin molly fish (Poecilia sphenops) fed with dried leaves of red hot chili pepper plants grown with formulated fertilizers. This study showcased a pioneering investigation into the synthesis of microcapsules using synthesized hydrogel beads along with digital image processing for bio-waste management and sustainable agro-application.