Properties of carbon nanotube-dispersed Sr-hydroxyapatite injectable material for bone defects

This study concerns the synthesis of gel materials based on carbon nanotubes dispersed strontium-modified hydroxyapatite(Sr-HA)at different compositions obtained by sol–gel technology and their influence on human-bone-marrow-derived mesenchymal stem cells.Furthermore,an evaluation of the influence of nanotubes and Strontium on physico-chemical,morphological,rheological and biological properties of hydroxyapatite gel was also performed.Morphological analysis(scanning electron microscopy)shows a homogeneous distribution of modified nanotubes in the ceramic matrix improving the bioactive properties of materials.The biological investigations proved that Sr-HA/carbon nanotube gel containing 0–20 mol(%)of Sr showed no toxic effect and promote the expression of early and late markers of osteogenic differentiation in cell culture performed in basal medium without osteogenic factors.Finally,the SrHA/carbon nanotube gels could have a good potential application as filler in bone repair and regeneration and may be used in the osteoporotic disease treatment.

Preliminary focus on the mechanical and antibacterial activity of a PMMA-based bone cement loaded with gold nanoparticles

In total knee arthroplasty(TKA)and total hip replacement(THR)the restoration of the normal joint function represents a fundamental feature.A prosthetic joint must be able to provide motions and to transmit functional loads.As reported in the literature,the stress distribution may be altered in bones after the implantation of a total joint prosthesis.Some scientific works have also correlated uncemented TKA to a progressive decrease of bone density below the tibial component.Antibiotic-loaded bone cements are commonly employed in conjunction with systemic antibiotics to treat infections.Furthermore,nanoparticles with antimicrobial activity have been widely analysed.Accordingly,the current research was focused on a preliminary analysis of the mechanical and antibacterial activity of a PMMA-based bone cement loaded with gold nanoparticles.The obtained results demonstrated that nanocomposite cements with a specific concentration of gold nanoparticles improved the punching performance and antibacterial activity.However,critical aspects were found in the optimization of the nanocomposite bone cement.

Surface functionalization of acrylic based photocrosslinkable resin for 3D printing applications

The limited number of resins,available for stereolithography applications,is one of the key drivers in research applied to rapid prototyping.In this work an acrylic photocrosslinkable resin based on methyl methacrylate(MMA),butyl methacrylate(BMA)and poly(ethylene glycol)dimethacrylate(PEGDA)was developed with different composition and characterized in terms of mechanical,thermal and biological behaviour.Two different systems have been developed using different amount of reagent.The influence of every components have been evaluated on the final characteristic of the resin in order to optimize the final composition for applications in bone tissue engineering.The crosslinked materials showed good mechanical properties and thermal stabilities and moreover cytotoxicity test confirms good biocompatibility with no cytotoxic effect on cells metabolism.Moreover two different treatments have been proposed,using fetal bovine serum(FBS)and methanol(MeOH),in order to improve cell recognition of the surfaces.Samples threatened with MeOH allow cell adhesion and survival,promoting spreading,elongation and fusion of C2C12 muscle myoblast cells.

In situ sol-gel synthesis of hyaluronan derivatives bio-nanocomposite hydrogels

The main driving idea of the present study was the comparison between two different chemical modifications of hyaluronic acid(HA)followed by the development of nanocomposite hydrogels directly in situ by biomineralization of photocrosslinkable HA polymers through sol-gel synthesis.In this way,it has been possible to overcome some limitations due to classical approaches based on the physical blending of inorganic fillers into polymer matrix.To this aim,methacrylated and maleated HA,synthesized with similar degree of substitution(DS)were compared in terms of mechanical and physico-chemical properties.The success of in situ biomineralization was highlighted by reflect Fourier transform infrared spectroscopy and thermogravimetric analysis.Furthermore,mechanical characterization demonstrated the reinforcing effect of inorganic fillers evidencing a strong correlation with DS.The swelling behavior resulted to be correlated with filler concentration.Finally,the cytotoxicity tests revealed the absence of toxic components and an increase of cell proliferation over culture time was observed,highlighting these bio-nanocomposite hyaluronan derivatives as biocompatible hydrogel with tunable properties.