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Proteoglycans (PGs), also known as a viscous lubricant, is the main component of the cartilage extracellular matrix (ECM). The loss of PGs is accompanied by the chronic degeneration of cartilage tissue, which is an irreversible degeneration process that eventually develops into osteoarthritis (OA). Unfortunately, there is still no substitute for PGs in clinical treatments. Herein, we propose a new PGs analogue. The Glycopolypeptide hydrogels in the experimental groups with different concentrations were prepared by Schiff base reaction (Gel-1, Gel-2, Gel-3, Gel-4, Gel-5 and Gel-6). They have good biocompatibility and adjustable enzyme-triggered degradability. The hydrogels have a loose and porous structure suitable for the proliferation, adhesion, and migration of chondrocytes, good anti-swelling, and reduce the reactive oxygen species (ROS) in chondrocytes. In vitro experiments confirmed that the glycopolypeptide hydrogels significantly promoted ECM deposition and up-regulated the expression of cartilage-specific genes, such as type-II collagen, aggrecan, and glycosaminoglycans (sGAG). In vivo, the New Zealand rabbit knee articular cartilage defect model was established and the hydrogels were implanted to repair it, the results showed good cartilage regeneration potential. It is worth noting that the Gel-3 group, with a pore size of 122 ​± ​12 ​μm, was particularly prominent in the above experiments, and provides a theoretical reference for the design of cartilage-tissue regeneration materials in the future.

Our goal was to create bioimitated scaffolding materials for biomedical purposes. The guiding idea was that we used an interpenetrating structural hierarchy of natural extracellular matrix as a "pattern" to design hydrogel scaffolds that show favorable properties for tissue regeneration. Polymeric hydrogel scaffolds are made in a simple, environmentally friendly way without additional functionalization. Gelatin and 2-hydroxyethyl methacrylate were selected to prepare interpenetrating polymeric networks and linear alginate chains were added as an interpenetrant to study their influence on the scaffold's functionalities. Cryogelation and porogenation methods were used to obtain the designed scaffolding biomaterials. The scaffold's structural, morphological, and mechanical properties, in vitro degradation, and cell viability properties were assessed to study the effects of the preparation method and alginate loading. Apatite as an inorganic agent was incorporated into cryogelated scaffolds to perform an extensive biological assay. Cryogelated scaffolds possess superior functionalities essential for tissue regeneration: fully hydrophilicity, degradability and mechanical features (2.08–9.75 MPa), and an optimal LDH activity. Furthermore, cryogelated scaffolds loaded with apatite showed good cell adhesion capacity, biocompatibility, and non-toxic behavior. All scaffolds performed equally in terms of metabolic activity and osteoconductivity. Cryogelated scaffolds with/without HAp could represent a new advance to promote osteoconductivity and enhance hard tissue repair. The obtained series of scaffolding biomaterials described here can provide a wide range of potential applications in the area of biomedical engineering. [ABSTRACT FROM AUTHOR]

New composite 3D scaffolds were developed as a combination of synthetic polymer, poly(2-hydroxyethyl methacrylate) (PHEMA), and a natural polymer, gelatin, with a ceramic component, nanohydroxyapatite (ID nHAp) dopped with metal ions. The combination of a synthetic polymer, to be able to tune the structure and the physicochemical and mechanical properties, and a natural polymer, to ensure the specific biological functions of the scaffold, with inorganic filler was applied. The goal was to make a new material with superior properties for applications in the biomedical field which mimics as closely as possible the native bone extracellular matrix (ECM). Biodegradable PHEMA hydrogel was obtained by crosslinking HEMA by poly(β-amino esters) (PBAE). The scaffold’s physicochemical and mechanical properties, in vitro degradation, and biological activity were assessed so to study the effects of the incorporation of nHAp in the (PHEMA/PBAE/gelatin) hydrogel, as well as the effect of the different pore-forming methods. Cryogels had higher elasticity, swelling, porosity, and percent of mass loss during degradation than the samples obtained by porogenation. The composite scaffolds had a higher mechanical strength, 10.14 MPa for the porogenated samples and 5.87 MPa for the cryogels, but a slightly lower degree of swelling, percent of mass loss, and porosity than the hybrid ones. All the scaffolds were nontoxic and had a high cell adhesion rate, which was 15–20% higher in the composite samples. Cell metabolic activity after 2 and 7 days of culture was higher in the composites, although not statistically different. After 28 days, cell metabolic activity was similar in all scaffolds and the TCP control. No effect of integrating nHAp into the scaffolds on osteogenic cell differentiation could be observed. Synergetic effects occurred which influenced the mechanical behavior, structure, physicochemical properties, and interactions with biological species.

Hydrogel scaffolding biomaterials are one of the most attractive polymeric biomaterials for regenerative engineering and can be engineered into tissue mimetic scaffolds to support cell growth due to their similarity to the native extracellular matrix. The novel, versatile hydrogel scaffolds based on alginate, gelatin, 2-hydroxyethyl methacrylate, and inorganic agent hydroxyapatite were prepared by modified cryogelation. The chemical composition, morphology, porosity, mechanical properties, effects on cell viability, in vitro degradation, in vitro and in vivo biocompatibility were tested to correlate the material’s composition with the corresponding properties. Scaffolds showed an interconnected porous microstructure, satisfactory mechanical strength, favorable hydrophilicity, degradation, and suitable in vitro and in vivo biocompatible behavior. Materials showed good biocompatibility with healthy human fibroblast in cell culture, as well as in vivo with zebrafish assay, suggesting newly synthesized hydrogel scaffolds as a potential new generation of hydrogel scaffolding biomaterials with tunable properties for versatile biomedical applications and tissue regeneration.

Proteoglycans (PGs), also known as a viscous lubricant, is the main component of the cartilage extracellular matrix (ECM). The loss of PGs is accompanied by the chronic degeneration of cartilage tissue, which is an irreversible degeneration process that eventually develops into osteoarthritis (OA). Unfortunately, there is still no substitute for PGs in clinical treatments. Herein, we propose a new PGs analogue. The Glycopolypeptide hydrogels in the experimental groups with different concentrations were prepared by Schiff base reaction (Gel-1, Gel-2, Gel-3, Gel-4, Gel-5 and Gel-6). They have good biocompatibility and adjustable enzyme-triggered degradability. The hydrogels have a loose and porous structure suitable for the proliferation, adhesion, and migration of chondrocytes, good anti-swelling, and reduce the reactive oxygen species (ROS) in chondrocytes. In vitro experiments confirmed that the glycopolypeptide hydrogels significantly promoted ECM deposition and up-regulated the expression of cartilage-specific genes, such as type-II collagen, aggrecan, and glycosaminoglycans (sGAG). In vivo, the New Zealand rabbit knee articular cartilage defect model was established and the hydrogels were implanted to repair it, the results showed good cartilage regeneration potential. It is worth noting that the Gel-3 group, with a pore size of 122 ​± ​12 ​μm, was particularly prominent in the above experiments, and provides a theoretical reference for the design of cartilage-tissue regeneration materials in the future., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2023 The Authors.)

Spherical macroporous poly(lactic‐co‐glycolic acid) (PLGA) has been synthesised using an emulsion method. Polyvinyl alcohol and Pluronic F127 have been used as dispersing and porogen agent, respectively. The diameter of the spherical PLGA is about 20 μm and the pore size of the PLGA macroporous is about 2–2.5 μm observed by scanning electron microscopy. After immersing in simulated body fluid, the PLGA materials can induce the formation of hydroxyapatite (HAP) on their surface. The HAP‐PLGA has been obtained and used as the host for drug release. Furthermore, the drug‐loaded samples possess the various drug release performance by adjusting the thickness of the HAP layer. This highly satisfied composite material is expected to be promising in the applications in tissue regeneration engineering. [ABSTRACT FROM AUTHOR]

New composite 3D scaffolds were developed as a combination of synthetic polymer, poly(2-hydroxyethyl methacrylate) (PHEMA), and a natural polymer, gelatin, with a ceramic component, nanohydroxyapatite (ID nHAp) dopped with metal ions. The combination of a synthetic polymer, to be able to tune the structure and the physicochemical and mechanical properties, and a natural polymer, to ensure the specific biological functions of the scaffold, with inorganic filler was applied. The goal was to make a new material with superior properties for applications in the biomedical field which mimics as closely as possible the native bone extracellular matrix (ECM). Biodegradable PHEMA hydrogel was obtained by crosslinking HEMA by poly(β-amino esters) (PBAE). The scaffold's physicochemical and mechanical properties, in vitro degradation, and biological activity were assessed so to study the effects of the incorporation of nHAp in the (PHEMA/PBAE/gelatin) hydrogel, as well as the effect of the different pore-forming methods. Cryogels had higher elasticity, swelling, porosity, and percent of mass loss during degradation than the samples obtained by porogenation. The composite scaffolds had a higher mechanical strength, 10.14 MPa for the porogenated samples and 5.87 MPa for the cryogels, but a slightly lower degree of swelling, percent of mass loss, and porosity than the hybrid ones. All the scaffolds were nontoxic and had a high cell adhesion rate, which was 15-20% higher in the composite samples. Cell metabolic activity after 2 and 7 days of culture was higher in the composites, although not statistically different. After 28 days, cell metabolic activity was similar in all scaffolds and the TCP control. No effect of integrating nHAp into the scaffolds on osteogenic cell differentiation could be observed. Synergetic effects occurred which influenced the mechanical behavior, structure, physicochemical properties, and interactions with biological species.

Hydrogel scaffolding biomaterials are one of the most attractive polymeric biomaterials for regenerative engineering and can be engineered into tissue mimetic scaffolds to support cell growth due to their similarity to the native extracellular matrix. The novel, versatile hydrogel scaffolds based on alginate, gelatin, 2-hydroxyethyl methacrylate, and inorganic agent hydroxyapatite were prepared by modified cryogelation. The chemical composition, morphology, porosity, mechanical properties, effects on cell viability, in vitro degradation, in vitro and in vivo biocompatibility were tested to correlate the material's composition with the corresponding properties. Scaffolds showed an interconnected porous microstructure, satisfactory mechanical strength, favorable hydrophilicity, degradation, and suitable in vitro and in vivo biocompatible behavior. Materials showed good biocompatibility with healthy human fibroblast in cell culture, as well as in vivo with zebrafish assay, suggesting newly synthesized hydrogel scaffolds as a potential new generation of hydrogel scaffolding biomaterials with tunable properties for versatile biomedical applications and tissue regeneration. [ABSTRACT FROM AUTHOR]