Biocompatibility and bioactivity of PDLLA/TiO2 and PDLLA/TiO2/Bioglass® nanocomposites

Development of 3D-printed PLGA/TiO2 nanocomposite scaffolds for bone tissue engineering applications

Porous scaffolds were 3D-printed using poly lactic-co-glycolic acid (PLGA)/TiO2 composite (10:1 weight ratio) for bone tissue engineering applications. Addition of TiO2 nanoparticles improved the compressive modulus of scaffolds. Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) revealed an increase in both glass transition temperature and thermal decomposition onset of the composite compared to pure PLGA. Furthermore, addition of TiO2 was found to enhance the wettability of the surface evidenced by reducing the contact angle from 90.5 ± 3.2 to 79.8 ± 2.4 which is in favor of cellular attachment and activity. The obtained results revealed that PLGA/TiO2 scaffolds significantly improved osteoblast proliferation compared to pure PLGA (p < 0.05). Furthermore, osteoblasts cultured on PLGA/TiO2 nanocomposite showed significantly higher ALP activity and improved calcium secretion compared to pure PLGA scaffolds (p < 0.05).

A Biomimetic Material with a High Bio-responsibility for Bone Reconstruction and Tissue Engineering

A biomimetic composite was prepared using type-I collagen as the matrix, and particles of sol-gel-derived bioactive glass (58S), hyaluronic acid and phosphatidylserine as additives. The material has an interconnected 3-D porous structure with a porosity > 85%. When incubated in simulated body fluid (SBF), the composite induced the formation of microcrystals of bone-like hydroxyapatite (HA), suggesting good bioactive properties. During the in vitro cell-culture experiment, MC3T3-E1 cells adhered to, migrated and spread on the surface of the porous composite. The material was employed to repair a 10-mm defect in a rabbit's radius. The composite was gradually degraded within 8 weeks and replaced by new bone. After 12 weeks, the bone marrow cavity was restored and the Haversian canal was noted from the histological observation. The biomimetic composite is a potential scaffold material for bone reconstruction and bone tissue engineering.

Fabrication of interpenetrate chitosan: bioactive glass, using dense gas CO2

Success of bone tissue engineering relies on using bioactive scaffolds with ideal pore morphology which can mimic the properties of the natural extracellular matrix (ECM). The objective of this study was to interpenetrate bioactive glass components throughout the three dimensional (3D) structure of the chitosan scaffold to increase the average pore size of the scaffold and also the osteoconductivity and osteoinductivity of the fabricated scaffold. Scanning electron microscopy was used to observe the microsturcture of the hydrogel. The results of this study demonstrated that the average pore size in the hydrogel was increased significantly (p<0.05) from 97 ± 44 μm to 150 ± 24 μm by increasing the BG concentration from 0 wt% to 40 wt%. This effect might be due to the interaction between ceramic and chitosan. The composite hydrogel fabricated swell in water and has high potential to be used for bone tissue engineering applications; bioactive glass can substantially improve bioactivity of the bone tissue engineering scaffolds However, further studies are required to investigate the effect of BG on the biocompatibility of the scaffolds. In addition, in vitro cell studies are also required to confirm the suitability of the fabricated scaffold for bone tissue engineering.

Retracted Article: Polycaprolactone composites with TiO2 for potential nanobiomaterials: tunable properties using different phases

TiO₂ nanoparticles of different phases play a key role in property alteration of nanocomposite fibers.

Computational modelling of the mechanical environment of osteogenesis within a polylactic acid-calcium phosphate glass scaffold

A computational model based on finite element method (FEM) and computational fluid dynamics (CFD) is developed to analyse the mechanical stimuli in a composite scaffold made of polylactic acid (PLA) matrix with calcium phosphate glass (Glass) particles. Different bioreactor loading conditions were simulated within the scaffold. In vitro perfusion conditions were reproduced in the model. Dynamic compression was also reproduced in an uncoupled fluid-structure scheme: deformation level was studied analyzing the mechanical response of scaffold alone under static compression while strain rate was studied considering the fluid flow induced by compression through fixed scaffold. Results of the model show that during perfusion test an inlet velocity of 25 microm/s generates on scaffold surface a fluid flow shear stress which may stimulate osteogenesis. Dynamic compression of 5% applied on the PLA-Glass scaffold with a strain rate of 0.005 s(-1) has the benefit to generate mechanical stimuli based on both solid shear strain and fluid flow shear stress on large scaffold surface area. Values of perfusion inlet velocity or compression strain rate one order of magnitude lower may promote cell proliferation while values one order of magnitude higher may be detrimental for cells. FEM-CFD scaffold models may help to determine loading conditions promoting bone formation and to interpret experimental results from a mechanical point of view.