Fabrication of a three-dimensional printed gelatin/sodium alginate/nano-attapulgite composite polymer scaffold loaded with leonurine hydrochloride and its effects on osteogenesis and vascularization

Gelatin/chitosan coating-embedded ZIF-8@DFO on Zn-EGCG: An effective strategy for treating infected bone defects

Titanium-based bone defect repair often encounters problems such as bacterial infection and excessive inflammation. In this study, firstly, tea polyphenol and zinc ion (E-Zn) coatings were prepared on titanium surface. Subsequently, ZIF8@D (ZIF8 loaded with desferrioxamine) was loaded onto the E-Zn surface with the help of gelatin and chitosan (CG) to form an E-Zn/CG-ZIF8@D composite coating. The results demonstrated that the E-Zn/CG-ZIF8@D coating exhibited favorable hydrophilicity, corrosion resistance, and hemocompatible. In vitro, the coating boasted outstanding antimicrobial properties due to the antimicrobial effects of Zn2+ against E. coli and S. aureus. Leveraging the anti-inflammatory properties of Zn2+, the coating could modulate the polarization of macrophages (RAW264.7) to the M2 type. Thanks to the vascularization-inducing properties of desferrioxamine, the coating could prompt the vascularization of human umbilical vein endothelial cells (HUVEC). Relying on the osteogenic properties of Zn2+, the coating could drive the differentiation of preosteoblasts (MC3T3-E1) towards osteogenesis. In vivo experiments indicated that the E-Zn/CG-ZIF8@D manifested excellent anti-inflammatory, antibacterial, angiogenic, and bone repair capabilities. This surface engineering strategy is highly effective. It constructs favorable bone-implant interfaces. It does this by integrating multiple functions. As a result, the likelihood of implant failure is significantly reduced.

A novel pH-responsive berberine-loaded attapulgite microsphere for IBD therapy via the regulation of gut immunity and flora

Inflammatory bowel disease (IBD) is an idiopathic, lifelong, and devastating chronic inflammatory disease of the gastrointestinal tract. Berberine, an alkaloid extracted from the Chinese herb Huanglian, is a pharmaceutical ingredient with antibacterial, anti-inflammatory, and antiviral pharmacological effects in Chinese medicine. However, direct administration of berberine requires high doses due to its low bioavailability and high waste in the stomach. In this study, we prepared berberine-loaded pH-responsive Eudragit® FS 30D-attapulgite (FS-ATT) microspheres for the targeted treatment of colitis. The microspheres had pH-responsive release behavior, with minimal berberine release (about 5.97%) in simulated gastric fluid and high berberine release in simulated colonic fluid (about 69.27%). In addition, it was revealed by in vivo biological evaluations that, compared with drugs in an equivalent solution form taken orally, a significant improvement in IBD symptoms was observed after oral administration of drug-loaded FS-ATT microspheres, leading to an increase in the diversity of intestinal microbiota, inhibition of inflammatory cytokines, and enhanced therapeutic effects of berberine. The pH-responsive FS-ATT microspheres could offer a promising drug delivery platform for managing and treating many gastrointestinal diseases.

Investigating How All-Trans Retinoic Acid Polycaprolactone (atRA-PCL) Microparticles Alter the Material Properties of 3D Printed Fibrin Constructs

The 3D printing of human tissue constructs requires carefully designed bioinks to support the growth and function of cells. Here it is shown that an additional parameter is how drug-releasing microparticles affect the material properties of the scaffold. A microfluidic platform is used to create all-trans retinoic acid (atRA) polycaprolactone (PCL) microparticles with a high encapsulation efficiency (85.9 ± 5.0%), and incorporate them into fibrin constructs to investigate their effect on the material properties. An encapsulation that is around 25-35% higher than the current state of the art batch methods is achieved. It is also found that the drug loading concentration affects the microparticle size, which can be controlled using the microfluidic platform. It is shown that the release of atRA is slower in fibrin constructs than in buffer, and that the presence of atRA in the microparticles modulates both the degradation and the rheological properties of the constructs. Finally, it is shown that the fibrin material exhibits a stronger solid-like state in the presence of atRA-PCL microparticles. These findings establish a basis for understanding the interplay between drug-releasing microparticles and scaffold materials, paving the way for bioinks that achieve tailored degradation and mechanical properties, together with sustained drug delivery for tissue engineering applications.

In vitro simulated digestion and fermentation characteristics of polyphenol-polysaccharide complex from Hizikia fusiforme and its effects on the human gut microbiota

This study investigated the effects of the polyphenol-polysaccharide complex (HPC) and its purified components (PC1 and PC4), obtained from Hizikia fusiforme, on the human gut microbiota during in vitro simulated digestion and fecal fermentation. Results showed a gradual increase in reducing sugar content for HPC, PC1, and PC4 during simulated digestion, accompanied by a slight decrease in molecular weight, indicating that these complexes were not completely digested during oral-gastrointestinal digestion. However, following fermentation, the molecular weights of HPC, PC1, and PC4 decreased significantly, and the molar ratios of monosaccharide compositions changed considerably compared with prefermentation values. Thus, these complexes were degraded and used by the intestinal microbiota to produce short-chain fatty acids, which decreased the pH. In addition, after fecal fermentation, beneficial bacteria such as Bacteroides, Parabacteroides, and Bifidobacterium became more abundant, whereas the amount of harmful bacteria such as Fusobacterium and Escherichia/Shigella decreased, revealing the regulation by the complex on the intestinal microbiota. In conclusion, the polyphenol-polysaccharide complex improves the composition and abundance of the human gastrointestinal microbiota, thereby supporting gut health.

3D printed Aloe barbadensis loaded alginate-gelatin hydrogel for wound healing and scar reduction: In vitro and in vivo study

Wounds are one of the most critical clinical issues in plastic surgery repair and restoration. Conventional wound dressing materials cannot absorb enough wound exudates and shield the site from microbial infection. Also, despite their healing prowess, bioactive molecules from medicinal plants are less bioavailable at the wound sites. This study developed a 3D-printed hydrogel of sodium alginate and gelatin loaded with freeze-dried Aloe barbadensis extract for enhanced wound healing. The hydrogel was hydrophilic and showed an average pore size of 163.66 ± 14.45 μm, moderate swellability, and ideal mechanical properties with tensile strength(σ) of 16.39 ± 0.98 MPa, and Young's modulus of 17.43 ± 1.41 MPa. They showed potential antibacterial activity against Staphylococcus aureus (87.7 ± 4 % inhibition) and Pseudomonas aeruginosa (84.4 ± 6 % inhibition). These hydrogels were hemocompatible, biocompatible, and biodegradable. Cell cytotoxicity assay and scratch assay showed effective Normal Human Dermal Fibroblast cells (NHDF) viability, proliferation, and migration on the hydrogel. In vivo studies of the 3D-printed hydrogel demonstrated significantly improved wound closure, reduced wound contraction, enhanced epithelial regeneration with minimal inflammation, and decreased scar formation after 14 days of treatment. Therefore, this 3D-printed hydrogel can be promising for wound healing with scar reduction.

POM-Based Hydrogels for Efficient Synergistic Chemodynamic/Low-Temperature Photothermal Antibacterial Therapy

Bacterial infection of wound surfaces has posed a significant threat to human health and represents a formidable challenge in the clinical treatment. In this study, a novel antimicrobial hydrogel utilizing POM is synthesized as the primary component, with gelatin and sodium alginate as the structural framework. The resultant hydrogel demonstrates exceptional mechanical properties and viscoelasticity attributed to the hydrogen-bonded cross-linking between POM and gelatin, as well as the ionic cross-linking between sodium alginate and Ca2+. In addition, the integration of CuS nanoparticles conferred photothermal properties to the hydrogel system. To address the concerns regarding the potential thermal damage to the surrounding normal cells, this study employs a LT-PTT combined with CDT approach to achieve the enhanced antimicrobial efficacy while minimizing the inadvertent harm to the healthy cells. The findings suggested that POM-based hydrogels, serving as an inorganic-organic hybrid material, will represent a promising antimicrobial solution and offer valuable insights for the development of the non-antibiotic materials.

Attapulgite-Reinforced Cellulose Hydrogels with High Conductivity and Antifreezing Property for Flexible Sensors

Ionic conductive cellulose hydrogels are some of the most promising candidates for flexible sensors. However, it is difficult to simultaneously prepare cellulose hydrogels with high mechanical strength, good ionic conductivity, and antifreeze performance. In this work, a natural clay (attapulgite)-reinforced cellulose hydrogel was fabricated. Through a one-pot method, cellulose and attapulgite were dispersed in a concentrated ZnCl2 solution. The obtained hydrogel exhibited a dual network of hydrogen bonds and Zn2+-induced ionic interactions. Attapulgite serves as an inorganic filler that can regulate the hydrogen-bonding density among cellulose molecules and provides abundant channels for fast ion transport. By optimizing the attapulgite loading, a mechanically strong (compressive strength up to 1.10 MPa), tough (fracture energy up to 0.36 MJ m-3), highly ionic conductive (4.15 S m-1), and freezing-tolerant hydrogel was prepared. These hydrogels can be used for sensitive and stable human motion sensing, demonstrating their great potential for healthcare applications.

Nanoclay Reinforced Integrated Scaffold for Dual-Lineage Regeneration of Cartilage and Subchondral Bone

Tissue engineering is theoretically considered a promising approach for repairing osteochondral defects. Nevertheless, the insufficient osseous support and integration of the cartilage layer and the subchondral bone frequently lead to the failure of osteochondral repair. Drawing from this, it was proposed that incorporating glycine-modified attapulgite (GATP) into poly(1,8-octanediol-co-citrate) (POC) scaffolds via the one-step chemical cross-linking is proposed to enhance cartilage and subchondral bone defect repair simultaneously. The effects of the GATP incorporation ratio on the physicochemical properties, chondrocyte and MC3T3-E1 behavior, and osteochondral defect repair of the POC scaffold were also evaluated. In vitro studies indicated that the POC/10% GATP scaffold improved cell proliferation and adhesion, maintained cell phenotype, and upregulated chondrogenesis and osteogenesis gene expression. Animal studies suggested that the POC/10% GATP scaffold has significant repair effects on both cartilage and subchondral bone defects. Therefore, the GATP-incorporated scaffold system with dual-lineage bioactivity showed potential application in osteochondral regeneration.

3D-Printed Biomimetic Hydroxyapatite Composite Scaffold Loaded with Curculigoside for Rat Cranial Defect Repair

The treatment of various large bone defects has remained a challenge for orthopedic surgeons for a long time. Recent research indicates that curculigoside (CUR) extracted from the curculigo plant exerts a positive influence on bone formation, contributing to fracture healing. In this study, we employed emulsification/solvent evaporation techniques to successfully fabricate poly(ε-caprolactone) nanoparticles loaded with curculigoside (CUR@PM). Subsequently, using three-dimensional (3D) printing technology, we successfully developed a bioinspired composite scaffold named HA/GEL/SA/CUR@PM (HGSC), chemically cross-linked with calcium chloride, to ensure scaffold stability. Further characterization of the scaffold's physical and chemical properties revealed uniform pore size, good hydrophilicity, and appropriate mechanical properties while achieving sustained drug release for up to 12 days. In vitro experiments demonstrated the nontoxicity, good biocompatibility, and cell proliferative properties of HGSC. Through alkaline phosphatase (ALP) staining, Alizarin Red S (ARS) staining, cell migration assays, tube formation assays, and detection of angiogenic and osteogenic gene proteins, we confirmed the HGSC composite scaffold's significant angiogenic and osteoinductive capabilities. Eight weeks postimplantation in rat cranial defects, Micro-computed tomography (CT) and histological observations revealed pronounced angiogenesis and new bone growth in areas treated with the HGSC composite scaffold. These findings underscore the scaffold's exceptional angiogenic and osteogenic properties, providing a solid theoretical basis for clinical bone repair and demonstrating its potential in promoting vascularization and bone regeneration.

Food-packaging applications and mechanism of polysaccharides and polyphenols in multicomponent protein complex system: A review

With the increasingly mature research on protein-based multi-component systems at home and abroad, the current research on protein-based functional systems has also become a hot spot and focus in recent years. In the functional system, the types of functional factors and their interactions with other components are usually considered to be the subjective factors of the functional strength of the system. Because this process is accompanied by the transfer of protons and electrons in the system, it has antioxidant, antibacterial and anti-inflammatory properties. Polyphenols and polysaccharides have the advantages of wide source, excellent functionality and good compatibility with proteins, and have become excellent and representative functional factors. However, polyphenols and polysaccharides are usually accompanied by poor stability, poor solubility and low bioavailability when used as functional factors. Therefore, the effect of separate release and delivery will inevitably lead to non-significant or direct degradation. After forming a multi-component composite system with the protein, the functional factor will form a stable system driven by hydrogen bonds, hydrophobic forces and electrostatic forces between the functional factor and the protein. When used as a delivery system, it will protect the functional factor, and when released, through the specific recognition of the cell membrane receptor signal, the effect of fixed-point delivery is achieved. In addition, this multi-component composite system can also form a functional composite film by other means, which has a long-term significance for prolonging the shelf life of food and carrying out specific antibacterial.

Biomimetic Scaffolds-A Novel Approach to Three Dimensional Cell Culture Techniques for Potential Implementation in Tissue Engineering

Biomimetic scaffolds imitate native tissue and can take a multidimensional form. They are biocompatible and can influence cellular metabolism, making them attractive bioengineering platforms. The use of biomimetic scaffolds adds complexity to traditional cell cultivation methods. The most commonly used technique involves cultivating cells on a flat surface in a two-dimensional format due to its simplicity. A three-dimensional (3D) format can provide a microenvironment for surrounding cells. There are two main techniques for obtaining 3D structures based on the presence of scaffolding. Scaffold-free techniques consist of spheroid technologies. Meanwhile, scaffold techniques contain organoids and all constructs that use various types of scaffolds, ranging from decellularized extracellular matrix (dECM) through hydrogels that are one of the most extensively studied forms of potential scaffolds for 3D culture up to 4D bioprinted biomaterials. 3D bioprinting is one of the most important techniques used to create biomimetic scaffolds. The versatility of this technique allows the use of many different types of inks, mainly hydrogels, as well as cells and inorganic substances. Increasing amounts of data provide evidence of vast potential of biomimetic scaffolds usage in tissue engineering and personalized medicine, with the main area of potential application being the regeneration of skin and musculoskeletal systems. Recent papers also indicate increasing amounts of in vivo tests of products based on biomimetic scaffolds, which further strengthen the importance of this branch of tissue engineering and emphasize the need for extensive research to provide safe for humansbiomimetic tissues and organs. In this review article, we provide a review of the recent advancements in the field of biomimetic scaffolds preceded by an overview of cell culture technologies that led to the development of biomimetic scaffold techniques as the most complex type of cell culture.

Current Biomedical Applications of 3D-Printed Hydrogels

Three-dimensional (3D) printing, also known as additive manufacturing, has revolutionized the production of physical 3D objects by transforming computer-aided design models into layered structures, eliminating the need for traditional molding or machining techniques. In recent years, hydrogels have emerged as an ideal 3D printing feedstock material for the fabrication of hydrated constructs that replicate the extracellular matrix found in endogenous tissues. Hydrogels have seen significant advancements since their first use as contact lenses in the biomedical field. These advancements have led to the development of complex 3D-printed structures that include a wide variety of organic and inorganic materials, cells, and bioactive substances. The most commonly used 3D printing techniques to fabricate hydrogel scaffolds are material extrusion, material jetting, and vat photopolymerization, but novel methods that can enhance the resolution and structural complexity of printed constructs have also emerged. The biomedical applications of hydrogels can be broadly classified into four categories-tissue engineering and regenerative medicine, 3D cell culture and disease modeling, drug screening and toxicity testing, and novel devices and drug delivery systems. Despite the recent advancements in their biomedical applications, a number of challenges still need to be addressed to maximize the use of hydrogels for 3D printing. These challenges include improving resolution and structural complexity, optimizing cell viability and function, improving cost efficiency and accessibility, and addressing ethical and regulatory concerns for clinical translation.