In vitro and in vivo biocompatibility of calcium-phosphate scaffolds three-dimensional printed by stereolithography for bone regeneration.

Stereolithography (SLA) is an interesting manufacturing technology to overcome limitations of commercially available particulated biomaterials dedicated to intra-oral bone regeneration applications. The purpose of this study was to evaluate the in vitro and in vivo biocompatibility and osteoinductive properties of two calcium-phosphate (CaP)-based scaffolds manufactured by SLA three-dimensional (3D) printing. Pellets and macro-porous scaffolds were manufactured in pure hydroxyapatite (HA) and in biphasic CaP (HA:60-TCP:40). Physico-chemical characterization was performed using micro X-ray fluorescence, scanning electron microscopy (SEM), optical interferometry, and microtomography (µCT) analyses. Osteoblast-like MG-63 cells were used to evaluate the biocompatibility of the pellets in vitro with MTS assay and the cell morphology and growth characterized by SEM and DAPI-actin staining showed similar early behavior. For in vivo biocompatibility, newly formed bone and biodegradability of the experimental scaffolds were evaluated in a subperiosteal cranial rat model using µCT and descriptive histology. The histological analysis has not indicated evidences of inflammation but highlighted close contacts between newly formed bone and the experimental biomaterials revealing an excellent scaffold osseointegration. This study emphasizes the relevance of SLA 3D printing of CaP-based biomaterials for intra-oral bone regeneration even if manufacturing accuracy has to be improved and further experiments using biomimetic scaffolds should be conducted.

In vitro investigations of smart drug delivery systems based on redox-sensitive cross-linked micelles.

Redox-sensitive micelles are designed by using block copolymers of different architectures composed of a hydrophilic block of poly(ethylene oxide), and hydrophobic blocks of poly(ϵ-caprolactone) and poly(α-azide-ϵ-caprolactone). Stability of these micelles is insured in diluted media by cross-linking their core via the addition of a bifunctional cross-linker, while redox sensitivity is provided to these micelles by inserting a disulfide bridge in the cross-linker. The potential of these responsive micelles to be used as nanocarriers is studied in terms of cytotoxicity and cellular internalization. The release profiles are also investigated by varying the environment reductive strength.

Assessment of new-generation glistening-free hydrophobic acrylic intraocular lens material.

PURPOSE: To determine the hydrophobic, antiglistening, and bioadhesiveness properties of a new polymer, GF raw material, and to determine the suitability of this material for use in intraocular lenses (IOLs). SETTING: University of Liege, Liege, Belgium. DESIGN: Experimental study. METHODS: Intraocular lenses made of the new hydrophobic acrylic material were tested and compared with reference acrylic materials. The stability of their polymer matrix was estimated by testing for glistenings. The relative surface hydrophobicity was quantified via contact-angle measurements. The degrees of bioadhesiveness of the reference and test materials were assessed by in vitro porcine lens epithelial cell (LEC) culture. RESULTS: The glistening test showed that the new material had greater stability under worst-case conditions than previous-generation hydrophobic acrylic materials. The new polymer had the same hydrophobic properties as the hydrophobic Acrysof IQ SN60WF material; both materials were less hydrophobic than the hydrophobic Sensar AR40e material and more hydrophobic than the hydrophilic Ioflex IOL material. The in vitro bioadhesiveness tests showed that porcine LEC adhesion levels of the new material were intermediate with respect to those of the 2 reference hydrophobic materials. CONCLUSIONS: When equilibrated in aqueous medium, the new-generation hydrophobic acrylic material reached a low water content at equilibrium, making it glistening free. The hydrophobicity and bioadhesiveness of the new raw material were comparable to those of state-of-the-art reference materials; these properties may resist the formation of posterior capsule opacification. FINANCIAL DISCLOSURE: Dr. Pagnoulle has a proprietary interest in the GF material. Drs. Pagnoulle, Gobin, and Bozukova are employees of Physiol S.A. Mme. V. Bertrand and Dr. Gillet-De Pauw have no financial or proprietary interest in any material or method mentioned.