Scaffolds for bone tissue engineering must meet a number of requirements such as biocompatibility, osteoconductivity, osteoinductivity, biodegradability, and appropriate biomechanical properties. A combination of type I collagen and 45S5 Bioglass may meet these requirements, however, little has been demonstrated on the effect of Bioglass on the potential of the collagen nanofibrillar three-dimensional mineralization and its influence on the structural and mechanical properties of the scaffolds. In this work, rapidly fabricated dense collagen-Bioglass hybrid scaffolds were assessed for their potential for immediate implantation. Hybrid scaffolds were conditioned, in vitro, in simulated body fluid (SBF) for up to 14 days and assessed in terms of changes in structural, chemical, and mechanical properties. MicroCT and SEM analyses showed a homogeneous distribution of Bioglass particles in the as-made hybrids. Mineralization was detected at day 1 in SBF, while ATR-FTIR microscopy and XRD revealed the presence of hydroxyl-carbonated apatite on the surface and within the two hybrid scaffolds at days 7 and 14. FTIR and SEM confirmed that the triple helical structure and typical banding pattern of fibrillar collagen was maintained as a function of time in SBF. Principal component analysis executed on ATR-FTIR microscopy revealed that the mineralization extent was a function of both Bioglass content and conditioning time in SBF. Tensile mechanical analysis showed an increase in the elastic modulus and a corresponding decrease in strain at ultimate tensile strength (UTS) as imparted by mineralization of scaffolds as a function of time in SBF and Bioglass content. Change in UTS was affected by Bioglass content. These results suggested the achievement of a hybrid matrix potentially suitable for bone tissue engineering.
"In fact, some recent studies on BGn-incorporated biological polymers, including collagen, alginate and chitosan, have demonstrated enhanced biological properties, such as the stimulation of proliferation of osteoblasts and mesenchymal stem cells, and their osteogenic differentiation  . One promising BGn–collagen combination that has been developed is in a physically compressed form  . Physical compression squeezes excessive water from the collagen gel matrix, enabling physically dense and mechanically strengthened constructs. "
[Show abstract][Hide abstract] ABSTRACT: Collagen (Col) hydrogels have poor physicochemical and mechanical properties and are susceptible to substantial shrinkage during cell culture, which limits their potential applications in hard tissue engineering. Here, we developed novel nanocomposite hydrogels made of collagen and mesoporous bioactive glass nanoparticle (mBGn) with surface amination, and addressed the effects of mBGn addition (Col: mBG = 2:1, 1:1 and 1:2) and its surface amination on the physicochemical and mechanical properties of the hydrogels. The amination of mBGn was shown to enable chemical bonding with collagen molecules. As a result, the nanocomposite hydrogels exhibited a significantly improved physicochemical and mechanical stability. The hydrolytic and enzymatic degradation of the Col-mBGn hydrogels were slowed down due to the incorporation of mBGn and its surface amination. Mechanical properties of the hydrogels, specifically the resistance to loading as well as the stiffness significantly increased with addition of mBGn and its aminated form, as assessed by a dynamical mechanical analysis. Mesenchymal stem cells cultivated within the Col-mBGn hydrogels were highly viable with enhanced cytoskeletal extensions due to the addition of surface aminated mBGn. While the Col hydrogel showed extensive shrinkage (down to ∼20% of initial size) during a few days of culture, the mBGn-added hydrogel exhibited substantially reduced shrinkage, and the aminated mBGn-added hydrogel had no observable shrinkage over 21 days. Results demonstrated the effective roles of the aminated mBGn in significantly improving the physicochemical and mechanical properties of Col hydrogel that is ultimately favorable for the applications in stem cell culture for bone tissue engineering.
[Show abstract][Hide abstract] ABSTRACT: A new family of biodegradable polymer/bioactive glass (BG) composite materials has emerged based on the availability of nano-sized bioactive particles. Such novel biocomposites can have enhanced performance, in terms of mechanical properties and bioactivity, and they can be designed to be used in bone regeneration approaches. In this work, membranes of chitosan (CTS) and chitosan with bioactive glass (BG) both micron and nano sized particles (CTS/μBG, CTS/nBG, respectively) were prepared by solvent casting. Microstructural and mechanical properties were evaluated in order to compare the effects of the incorporation of micro (μBG) and nano (nBG) particles in the chitosan matrix. In vitro bioactivity tests were performed to characterize the apatite layer that is formed on the surface of the material after being immersed in simulated body fluid (SBF). The biomineralization process on the biomaterials was also followed using non-conventional dynamic mechanical analysis (DMA), both online and offline. In such DMA experiments, the change in the storage modulus, E', and the loss factor, tan δ, were measured as a function of the immersion time in SBF. The results demonstrated that CTS/nBG membranes possess enhanced mechanical properties and higher bioactivity in comparison with the CTS/μBG membranes. Such results suggest the potential of nBG for the development of bioactive composites for bone regeneration applications.
"In fact, our previous studies have shown that bone marrow mesenchymal cells in vitro and bone formation in rat calvarium in vivo were greatly improved by the use of nBG . The ions to be released from the nBG component, such as calcium, phosphate and silicon, help differentiation and mineralization of the cells through ion-mediated reactions, as demonstrated in several other types of ion-eluting bioactive glass materials   . "
[Show abstract][Hide abstract] ABSTRACT: Collagen-based nanocomposite incorporating nanobioactive glass (Col/nBG) was developed as a scaffolding matrix for dentin-pulp regeneration. The effects of the novel matrix on the proliferation of human dental pulp cells (hDPCs) and their differentiation into odontoblastic lineage were investigated.
Nanocomposite scaffold was prepared by incorporating nBG within the Col solution and then reconstituting them into a membrane form. Cell growth by MTS assay, adhesion by scanning electron microscopy (SEM), and odontoblastic differentiation by alkaline phosphatase (ALP) activity, mineralization, and the mRNA expression of differentiation-related genes of DPCs on each scaffold were evaluated.
The introduction of nBG significantly improved the bone mineral-like apatite formation in the simulated body fluid, suggesting excellent acellular bone-bioactivity. The hDPCs cultured on the Col/nBG nanocomposite have shown active growth behavior during culture for 14 days. The mRNA levels of major organic extracellular matrix of dentin, collagen type I and III were highly expressed in the Col/nBG matrix. Moreover, the alkaline phosphatase (ALP) activity and the mineralized nodule formation were increased in the Col/nBG nanocomposite compared to those in Col. Odontoblatic differentiation genes, including dentin sialophosphoprotein, dentin matrix protein I, ALP, osteopontin and osteocalcin were significantly stimulated in the Col containing nBG. Moreover, the key adhesion receptor integrin components α2 and β1, specifically binding to collagen molecule sequence, were upregulated in Col/nBG compared to Col, suggesting that odontogenic stimulation was closely related to the integrin-mediated process.
In our study, the nanocomposite Col/nBG matrix induced the growth and odontogenic differentiation more effectively than Col alone, providing a promising scaffold condition for regeneration of dentin-pulp complex tissue.
Dental materials: official publication of the Academy of Dental Materials 09/2012; 28(12):1271-9. DOI:10.1016/j.dental.2012.09.011 · 3.77 Impact Factor
Data provided are for informational purposes only. Although carefully collected, accuracy cannot be guaranteed. The impact factor represents a rough estimation of the journal's impact factor and does not reflect the actual current impact factor. Publisher conditions are provided by RoMEO. Differing provisions from the publisher's actual policy or licence agreement may be applicable.