Enhanced bone tissue regeneration via bioactive electrospun fibrous composite coated titanium orthopedic implant

UCNPs-labeled electrospun scaffolds used to monitor in vivo degradation and bone tissue regeneration

Biodegradable electrospun bone repair materials are effective means to treat bone defects. However, because the electrospun substrates are mostly organic polymer materials, there is a lack of real-time and intuitive monitoring methods for their degradation in vivo. Therefore, it is of great significance to develop in vivo traced electrospun bone repair materials for postoperative observation of their degradation. In this research, polycaprolactone/up-conversion nanoparticles/magnesium oxide (PCL/UCNPs/MgO) composite scaffolds were prepared by electrospun based on the luminescence characteristics of up-conversion nanoparticles (UCNPs) under near infrared excitation and the osteogenic ability of MgO. The in vivo and in vitro degradation results showed that with the increase of time, the electrospun scaffolds gradually degraded and its luminescence intensity decreased. The addition of UCNPs can effectively monitor the degradation of the scaffolds. In addition, the prepared electrospun scaffolds had great biocompatibility, among which PCL-1%UCNPs-1%MgO (P1U1M) electrospun scaffolds had obvious effect on promoting osteogenic differentiation of mouse embryonic osteoblasts cells (MC3T3-E1) in vitro. In conclusion, P1U1M electrospun scaffolds have the potential to induce bone regeneration at bone defect sites, and can monitor the degradation of electrospun scaffolds. It may be a potential candidate material for bone regeneration in defect area.

Investigations into the effects of scaffold microstructure on slow-release system with bioactive factors for bone repair

In recent years, bone tissue engineering (BTE) has played an essential role in the repair of bone tissue defects. Although bioactive factors as one component of BTE have great potential to effectively promote cell differentiation and bone regeneration, they are usually not used alone due to their short effective half-lives, high concentrations, etc. The release rate of bioactive factors could be controlled by loading them into scaffolds, and the scaffold microstructure has been shown to significantly influence release rates of bioactive factors. Therefore, this review attempted to investigate how the scaffold microstructure affected the release rate of bioactive factors, in which the variables included pore size, pore shape and porosity. The loading nature and the releasing mechanism of bioactive factors were also summarized. The main conclusions were achieved as follows: i) The pore shapes in the scaffold may have had no apparent effect on the release of bioactive factors but significantly affected mechanical properties of the scaffolds; ii) The pore size of about 400 μm in the scaffold may be more conducive to controlling the release of bioactive factors to promote bone formation; iii) The porosity of scaffolds may be positively correlated with the release rate, and the porosity of 70%-80% may be better to control the release rate. This review indicates that a slow-release system with proper scaffold microstructure control could be a tremendous inspiration for developing new treatment strategies for bone disease. It is anticipated to eventually be developed into clinical applications to tackle treatment-related issues effectively.

Cissus quadrangularis L extract-loaded tricalcium phosphate reinforced natural polymer composite for guided bone regeneration

Natural medicines plants are significant considerable attention as potential therapeutic agents for bone tissue engineering. Cissus quadrangularis L (CQ). is a potent therapeutic plant known for its own osteogenic properties. In this research work, a phytoconstituents-filled composite was produced by incorporating CQ extract with gelatin (Gel) and pectin (Pec) polymers collective through β- tricalcium phosphate (β-TCP) bioceramic via a green template method. The effect of CQ-filled composite morphology and chemical structural properties, in vitro cytotoxicity, cell proliferation, and differentiation was investigated. FTIR spectroscopic results indicated the prepared materials' structural confirmation. The CQ extract was the alcoholic -OH merge with the hydroxyl and -NH groups in the range of 3000 cm^-1 to 3500 cm^-1. Scanning electron microscopy images showed that the β-TCP ceramic was perfectly embedded in Gel-Pec polymeric matrix, which is important for bone regeneration. In vitro cell culture results indicated that β-TCP/Gel-Pec/CQ composite provided 92.0% of a favorable substrate for mesenchymal stem cell viability. The gene expression and RT-PCR studies represent the materials with good osteogenic expression, especially the β-TCP/Gel-Pec/CQ composite is observed at 168.0% and 188.0% for RUNx2 and OCN, respectively. The result of the physicochemical characterizations and cell viability studies suggest that CQ-loaded β-TCP/Gel-Pec composite can serve as a potential biomaterial for bone tissue repair and regeneration.

Biofunctionalization with Cissus quadrangularis Phytobioactives Accentuates Nano-Hydroxyapatite Based Ceramic Nano-Cement for Neo-Bone Formation in Critical Sized Bone Defect

Developing biofunctionalized ceramic bone substitutes with phytobioactives for their sustained delivery is highly desired to enhance the osteo-active potential of ceramic bone substitutes, reduce the systemic toxicity of synthetic drugs, and increase the bioavailability of phytobioactives. The present work highlights the local delivery of phytobioactives of Cissus quadrangularis (CQ) through nano-hydroxyapatite (nHAP) based ceramic nano-cement. The phytoconstituent profiling represented the optimized CQ fraction to be rich in osteogenic polyphenols and flavonoids like quercetin, resveratrol, and their glucosides. Further, CQ phytobioactives-based formulation was biocompatible, increased bone formation, calcium deposition, proliferation, and migration of cells with simultaneous alleviation of cellular oxidative stress. In the in vivo critical-sized bone defect model, enhanced formation of highly mineralized tissue (BV mm³) in CQ phytobioactives functionalized nano-cement (10.5 ± 2 mm³) were observed compared to the control group (6.5 ± 1.2 mm³). Moreover, the addition of CQ phytobioactives to the bone nano-cement increased the fractional bone volume (BV/TV%) to 21 ± 4.2% compared to 13.1 ± 2.5% in non-functionalized nano-cement. The results demonstrated nHAP-based nano-cement as a carrier for phytobioactives which could be a promising approach for neo-bone formation in different bone defect conditions.

Dual-jet electrospun PDLGA/PCU nonwovens as promising mesh implant materials with controlled release of sirolimus and diclofenac

Dual-jet electrospinning was employed to produce two-component, partially degradable drug releasing nonwovens with interlacing of poly(D,L-lactide-co-glycolide) (PDLGA) and different poly(carbonate urethanes) (PCUs). Diclofenac sodium and sirolimus were released simultaneously from the copolyester carrier. The research focused on determining of release profiles of drugs, depending on the hydrophilicity of introduced PCU nanofibers. The influence of drugs incorporation on the hydrolytic degradation of the PDLGA and mechanical properties of nonwovens was also studied. Evaluation for interaction with cells in vitro was investigated on a fibroblast cell line in cytotoxicity and surface adhesion tests. Significant changes in drugs release rate, depending on the applied PCU were observed. It was also noticed, that hydrophilicity of drugs significantly influenced the hydrolytic degradation mechanism and surface erosion of the PDLGA, as well as the tensile strength of nonwovens. Tests carried out on cells in an in vitro experiment showed that introduction of sirolimus caused a slight reduction in the viability of fibroblasts as well as a strong limitation in their capability to colonize the surface of fibers. Due to improvement of mechanical strength and the ability to controlled drugs release, the obtained material may be considered as prospect surgical mesh implant in the treatment of hernia.

Advanced Nanofiber-Based Scaffolds for Achilles Tendon Regenerative Engineering

The Achilles tendon (AT) is responsible for running, jumping, and standing. The AT injuries are very common in the population. In the adult population (21–60 years), the incidence of AT injuries is approximately 2.35 per 1,000 people. It negatively impacts people’s quality of life and increases the medical burden. Due to its low cellularity and vascular deficiency, AT has a poor healing ability. Therefore, AT injury healing has attracted a lot of attention from researchers. Current AT injury treatment options cannot effectively restore the mechanical structure and function of AT, which promotes the development of AT regenerative tissue engineering. Various nanofiber-based scaffolds are currently being explored due to their structural similarity to natural tendon and their ability to promote tissue regeneration. This review discusses current methods of AT regeneration, recent advances in the fabrication and enhancement of nanofiber-based scaffolds, and the development and use of multiscale nanofiber-based scaffolds for AT regeneration.