RESUMEN
Beta-tricalcium phosphate (ß-TCP) scaffolds manufactured through the foam replication method are widely employed in bone tissue regeneration. The mechanical strength of these scaffolds is a significant challenge, partly due to the rheological properties of the original suspension. Various strategies have been explored to enhance the mechanical properties. In this research, ß-TCP scaffolds containing varying concentrations (0.25-1.00 wt%) of multi-walled carbon nanotubes (MWCNT) were developed. The findings indicate that the addition of MWCNTs led to a concentration-dependent improvement in the viscosity of ß-TCP suspensions. All the prepared slurries exhibited viscoelastic behavior, with the storage modulus surpassing the loss modulus. The three time interval tests revealed that MWCNT-incorporated ß-TCP suspensions exhibited faster structural recovery compared to pure ß-TCP slurries. Introducing MWCNT modified compressive strength, and the optimal improvement was obtained using 0.75 wt% MWCNT. The in vitro degradation of ß-TCP was also reduced by incorporating MWCNT. While the inclusion of carbon nanotubes had a marginal negative impact on the viability and attachment of MC3T3-E1 cells, the number of viable cells remained above 70% of the control group. Additionally, the results demonstrated that the scaffold increased the expression level of osteocalcin, osteoponthin, and alkaline phosphatase genes of adiposed-derived stem cells; however, higher levels of gene expersion were obtained by using MWCNT. The suitability of MWCNT-modified ß-TCP suspensions for the foam replication method can be assessed by evaluating their rheological behavior, aiding in determining the critical additive concentration necessary for a successful coating process.
Asunto(s)
Fosfatos de Calcio , Nanotubos de Carbono , Ingeniería de Tejidos , Andamios del Tejido , Fosfatos de Calcio/química , Nanotubos de Carbono/química , Andamios del Tejido/química , Ingeniería de Tejidos/métodos , Animales , Ratones , Línea Celular , Huesos/metabolismo , Supervivencia Celular/efectos de los fármacos , Ensayo de Materiales , Regeneración Ósea/efectos de los fármacos , Osteoblastos/metabolismo , Osteoblastos/efectos de los fármacos , Osteoblastos/citología , ViscosidadRESUMEN
The aim of this study is to fabricate a highly porous scaffold based on gelatin/sodium alginate/45S5 bioglass with improved mechanical strength. Glycidoxypropyltrimethoxysilane (GPTMS) is used as a cross-linker and for the first time a nonionic bio-surfactant (Tween 80) is introduced to the composition to evaluate whether the essential properties of a suitable scaffold for bone substitution can be reached or not. The composite scaffolds are prepared through freeze-drying of suspension containing various ratios of gelatin/sodium alginate/45S5 bioglass. Characterization of fabricated scaffolds is carried out. SEM micrographs reveal that all samples are highly porous however incorporation of 1% v/v tween 80 results in well-shaped pores, with sizes ranging between 100 and 200 µm which is appropriate for tissue regeneration. Compressive strength of foamed scaffolds in contact with body solution has been enhanced from 0.37 to 1.41 MPa due to addition of tween 80. Foamed scaffold reinforced with tween 80 maintained its structural stability within 7 days immersion in simulated body fluid (SBF) despite the absorption of water 15 times its weight. Moreover, in vitro calcium phosphate precipitation is well observed on the surface of scaffolds.
Asunto(s)
Alginatos/química , Huesos/citología , Cerámica/química , Gelatina/química , Polisorbatos/química , Silanos/química , Andamios del Tejido/química , Materiales Biocompatibles/química , Materiales Biocompatibles/farmacología , Fenómenos Mecánicos , Porosidad , Tensoactivos/química , Ingeniería de TejidosRESUMEN
In recent years, there has been a great interest in using natural polymers in the composition of calcium phosphate bone cements to enhance their physical, mechanical, and biological performance. Gelatin is a partially hydrolyzed form of collagen, a natural component of bone matrix. In this study, the effect of blooming gelatin on the nanohydroxyapatite precipitation, physical and mechanical properties, and cellular responses of a calcium phosphate bone cement (CPC) was investigated. Various concentrations of blooming gelatin (2, 5, and 8 wt.%) were used as the cement liquid and an equimolar mixture of tetracalcium phosphate and dicalcium phosphate was used as solid phase. The CPC without any gelatin additive was also evaluated as a control group. The results showed that gelatin accelerated hydraulic reactions of the cement paste, in which the reactants were immediately converted into nanostructured apatite precipitates after hardening. Gelatin molecules induced 4%-10% macropores (10-300 µm) into the cement structure, decreased initial setting time by ~190%, and improved mechanical strength of the as-set cement. Variation in the above-mentioned properties was influenced by the gelatin concentration and progressed with increasing the gelatin content. The numbers of the G-292 osteoblastic cells on gelatin-containing CPCs were higher than the control group at entire culture times (1-14 days), meanwhile better alkaline phosphatase (ALP) activity was determined using blooming gelatin additive. The observation of cell morphologies on the cement surfaces revealed an appropriate cell attachment with extended cell membranes on the cements. Overall, adding gelatin to the composition of CPC improved the handling characteristics such as setting time and mechanical properties, enhanced nanoapatite precipitation, and augmented the early cell proliferation rate and ALP activity.