Corneliu Cincu

Biomimetic potential of some methacrylate-based copolymers: A comparative study

Preparation of new biocompatible materials for bone recovery has consistently gained interest in the last few decades. Special attention was given to polymers that contain negatively charged groups, such as phosphate, carboxyl, and sulfonic groups toward calcification. This present paper work demonstrates that other functional groups present also potential application in bone pathology. New copolymers of 2-hydroxyethyl methacrylate with diallyldimethylammonium chloride (DADMAC), glycidyl methacrylate (GlyMA), methacrylic acid (MAA), 2-methacryloyloxymethyl acetoacetate (MOEAA), 2-methacryloyloxyethyltriethylammonium chloride (MOETAC), and tetrahydrofurfuryl methacrylate (THFMA) were obtained. The copolymers were characterized by FTIR, swelling potential, and they were submitted to in vitro tests for calcification and cytotoxicity evaluation. GlyMA and MOETAC-containing copolymers show promising results for further in vivo mineralization tests, as a potential alternative to the classical bone grafts, in bone tissue engineering.

Aluminum inhibits the growth of hydroxyapatite crystals developed on a biomimetic methacrylic polymer.

PROJECT Aluminum (Al) is an increasing problem in biomedicine since it can interact with phosphates. Bone is one of the preferential target tissues of Al deposition: Al interacts with mineralization and/or bone cell activities. We searched the influence of Al deposition in hydroxyapatite developed on a biomimetic polymer (carboxymethylated poly(2-hydroxyethyl-methacrylate)) which mimics bone mineralization in the absence of cells. PROCEDURES Pellets of polymer were incubated for 5 days in a synthetic body fluid (SBF) to induce mineralization, then 21 days in SBF containing 20, 40 and 60 μg/L Al(3+). Other pellets were incubated in SBF containing commercial Al foil (33 mg/vial) either in 1, 2 or 6 pieces. The mineral deposits were dissolved in HCl and Ca(2+), PO(4)(3-) and Al(3+) content was measured. Hydroxyapatite was characterized by SEM and X energy-dispersive X-ray analysis (EDX). RESULTS The amount of Al(3+) was dose-dependently increased in Ca/P deposits on the polymer pellets. At high concentration (or with the 6 Al foils) growth of hydroxyapatite calcospherite was inhibited; only calcified plates emerging from the polymer were observed. Pellets incubated with 1 and 2 Al foils exhibited a reduction in calcospherite diameter and an increase in the Al(3+)/Ca(2+) ratio. EDX identified Al in the mineral deposits. CONCLUSIONS In this acellular model, Al(3+) altered the growth of calcospherites at low concentration and inhibited their development at high concentration. In SBF, a release of Al(3+) from aluminum foils also inhibited mineralization. This study emphasizes the importance of Al in bone pathology and stresses the question of its release from biomaterials.

Superficial Grafting of Water-Soluble Polymers on Brominated MWCNT by ATRP Technique

Multiwall carbon nanotubes (CNTs) have been brominated by photochemical bromine addition. XPS analysis has been used to determine the amount of bromine reacted. By measuring the concentrations of the co-initiator and the monomer, multiwall carbon nanotubes functionalized with hydrosoluble polymers—polyhydroxyethylacrylate (PHEA) and polyacrylamide (PAAM)—have been obtained and characterized using the Raman, SEM, and XPS depth profile techniques. The 3-D structure of the composite films obtained from the functionalized CNTs has been studied as well.

Hybrid material based on ST–AA photonic crystal core and ZnO particle shell

The aim of this study was to obtain a hybrid material based on a polymer photonic crystal core and inorganic ZnO shell with potential applications in optoelectronic devices or photocatalysts. For this reason, ZnO particles were obtained both in the absence and presence of ST–AA particles using a chemical reduction method for metal salts. The inhibited growth mechanism of inorganic particles generated in the presence of polymer latex was noticed. The products were characterized by SEM, EDX, TEM, DLS, and UV–vis.

Triiodophenyl acrylate-based microbeads find important use in the medical field

Preparation of polymeric micro- and nanoparticles has significantly become an effective approach for achieving efficient drug targeting to tumour tissues. A promising solution could be the use of a radio-opaque polymeric system carrying iodine groups. In this context, radio-opaque polymeric microparticles based on methyl methacrylate (MMA) and an 2,4,6-triiodophenyl acrylate (TIPA) were synthesised by suspension and emulsion polymerisation techniques. Various compositions of p(MMA-co-TIPA) were physico-chemically and biologically characterised through FTIR-ATR, SEM, EDX, in vitro biocompatibility and X-ray measurements. These copolymers exhibit good in vitro cell compatibility together with good X-ray visibility so they are good candidates for tumour detection and imaging.