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Bone tissue engineering is a promising technology being studied globally to become an effective and sustainable method to treat the problems of damaged or diseased bones. In this work, we developed an in situ cross-linking hydrogel system that combined N-succinyl chitosan (NSC) and oxidized alginate (OA) at varying mixing ratios through Schiff base cross-linking. The hydrogel system also contains biphasic calcium phosphate (BCP) and ascorbic acid (AA), which could enhance biological characteristics and accelerate bone repair. The hydrogels' properties were examined through physicochemical tests such as scanning electron microscopy (SEM), energy-dispersive x-ray spectroscopy (EDS), Fourier transform infrared spectroscopy (FT-IR), x-ray diffraction (XRD), pore size and porosity measurement, swelling ratio, degradation rate, AA release study, as well as cytocompatibility, including live/dead and cytotoxicity assays. The results revealed that the supplementation of AA and BCP components can affect the physico-mechanical properties of the hydrogel system. However, they exhibited noncytotoxic properties. Overall, the results demonstrated that the hydrogel composed of 3% (w/v) NSC and 3% (w/v) OA (NSC: OA volume ratio is 8:2) loaded with 40% (w/w) BCP and 0.3 mg/mL AA has the potential for bone regeneration., (© 2024 Wiley Periodicals LLC.)

The design of three-dimensional (3D) scaffolds should focus on creating highly porous, 3D structures with an interconnected pore network that supports cell growth. The scaffold's pore interconnectivity is directly linked to vascularization, cell seeding, guided cell migration, and transportation of nutrients and metabolic waste. In this study, different types of food flavors including monosodium glutamate, sugar, and sodium chloride were used as the porogens along with PCL/PVP blend polymer for solvent casting/particulate leaching method. The morphology, porosity, interconnectivity, chemical composition, water absorption, and mechanical properties of the fabricated scaffolds are carefully characterized. The scaffolds are biocompatible in both in vitro and in vivo experiments and do not trigger any inflammatory response while enhancing new bone formation and vascularization in rabbit calvaria critical-sized defects. The new bone merges and becomes denser along with the experiment timeline. The results indicate that the 3D PCL/PVP scaffolds, using monosodium glutamate as porogen, exhibited suitable biological performance and held promise for bone tissue engineering in oral and maxillofacial surgery., (© 2024 IOP Publishing Ltd.)

Three dimensional porous scaffolds composed of various ratios of polycaprolactone and poly(L-lactic acid) (PLLA) were prepared using salt leaching method for bone regeneration applications. Surfaces of the scaffolds were visualized using scanning electron microscope (SEM) and the combination of the polymers was confirmed by FT-IR. Addition of PLLA increased the porosity and pore sizes of the scaffolds and also the scaffolds' compressive strength initially. Osteoblast-like cells were used and it was found that the samples' cell biocompatibility was further promoted with the increase in PLLA content as observed via cell proliferation assays using MTT, gene expression with RT-PCR, and micrographs from SEM and confocal microscopy. Samples were then implanted into male rabbits for 2 months, and histological staining and micro-CT histomorphometry show that new bone formations were detected in the site containing the implants of the scaffolds and that bone regeneration was further promoted with the increased concentration of PLLA in the scaffold.

In this study, porous poly(ε-caprolactone) (PCL) fiber-based fibrous scaffolds are created using a suitable ratio of dimethyl chloride and acetone by using electrospinning. With the porous structure, it induced CaP particles to easily coat on the fibers after immersion in simulated body fluid solution. The morphology of the electrospun membranes was observed using scanning electron microscopic observation. The results showed that the CaP coated successfully, as examined by scanning electron microscopy, energy-dispersive spectroscopy, X-ray diffraction, transmission electron microscopic techniques and mass comparative analysis. The wettability of the coated fibrous scaffolds was tested using contact angle analysis. The in vitro cellular proliferation and cell interaction with fibrous scaffolds were investigated. In addition, the in vivo bone formation capacity of fibrous scaffolds including the non-porous (PCL-DCM), porous (PCL-DCM/Ace) and CaP coating on PCL/DCM-Ace for 2, 4, 8 and 12 h immersed in SBF solution were also investigated. By measuring the in vitro results, we verified that porous PCL fiber-based fibrous scaffold after 12 h of immersion in simulated body fluid (PCL-DCM/Ace-12) was excellent for cell interaction, growth and proliferation. The in vivo analyses showed that the PCL-DCM/Ace-12 fibrous scaffold enabled greater acceleration of bone formation than PCL/DCM and PCL/DCM-Ace fibrous scaffolds.

Hemorrhagic shock is the leading cause of preventable deaths in traumatic accidents, emphasizing the significance of hemostasis-promoting materials and their incorporation into a pre-hospital medical response system. Bacterial cellulose has drawn much attention in tissue engineering due to its versatility and biocompatibility. In this study, a hemostatic dressing was composed of bacterial cellulose (BC) and chitosan oligosaccharide (COS), which is a well-known biological agent. The influence of chitosan oligosaccharide on the morphology, chemical, and physical properties of the fabricated cellulose membranes was evaluated. Additionally, the hemostatic performance of BC-COS membranes was investigated through in vitro and in vivo experiments. The results show that the addition of COS led to a lower mechanical strength while increasing the hemostatic properties of the BC membrane. The BC membrane modified with 2 w/v% COS solution (BC-COS2) demonstrated excellent hemostasis promotion through whole blood assays and mice hemorrhage model. The blood clotting index and blood clotting time of the BC-COS2 sample reached 86.25% and 190 s, respectively. Furthermore, in the in vivo experiments, the group treated using BC-COS2 also presented much lower bleeding stop time and blood loss compared to the untreated group. The results reveal the viability of the cellulosic material as a potential hemostatic dressing. [ABSTRACT FROM AUTHOR]

Three dimensional porous scaffolds composed of various ratios of polycaprolactone and poly(L-lactic acid) (PLLA) were prepared using salt leaching method for bone regeneration applications. Surfaces of the scaffolds were visualized using scanning electron microscope (SEM) and the combination of the polymers was confirmed by FT-IR. Addition of PLLA increased the porosity and pore sizes of the scaffolds and also the scaffolds' compressive strength initially. Osteoblast-like cells were used and it was found that the samples' cell biocompatibility was further promoted with the increase in PLLA content as observed via cell proliferation assays using MTT, gene expression with RT-PCR, and micrographs from SEM and confocal microscopy. Samples were then implanted into male rabbits for 2 months, and histological stain-ing and micro-CT histomorphometry show that new bone formations were detected in the site containing the implants of the scaffolds and that bone regeneration was further promoted with the increased concentration of PLLA in the scaffold. [ABSTRACT FROM AUTHOR]

AbstractOver the last decades, three-dimensional (3D) printing has emerged as one of the most promising alternative tissue and organ regeneration technologies. Recent advances in 3D printing technology, particularly in hydrogel-derived bioink formulations, offer promising solutions for fabricating intricate, biomimetic scaffolds that promote vascularization. In this review, we presented numerous studies that have been conducted to fabricate 3D-printed hydrogel vascularized constructs with significant advancements in printing integumentary systems, cardiovascular systems, vascularized bone tissues, skeletal muscles, livers, and kidneys. Furthermore, this work also discusses the engineering considerations, current challenges, proposed solutions, and future outlooks of 3D bioprinting. [ABSTRACT FROM AUTHOR]

• The densification of the PHS was controlled by the sintering temp and holding time. • At 1300 ℃, 30 min, MS samples were 33 % relative density and 2 MPa compressive strength. • Fine grains with higher density were found from the use of microwave sintering. • The Ag-coated on PHS was nano spherical, at about 79.8 ± 21.4 nm particle size. In this study, the optimization of the dual-frequency microwave sintering furnace in the replica method was investigated for the rapid synthesis of Porous hydroxyapatite scaffolds (PHS). It was found that by controlling the microwave sintering condition, it is possible to produce PHS with promising abilities for bone tissue engineering applications. [ABSTRACT FROM AUTHOR]