Porous biodegradable polyurethane nanocomposites: preparation, characterization, and biocompatibility tests

Abstract

A porous biodegradable polyurethane nanocomposite based on poly(caprolactone) (PCL) and nanocomponents derived from montmorillonite (Cloisite ® 30B) was synthesized and tested to produce information regarding its potential use as a scaffold for tissue engineering. Structural and morphological characteristics of this nanocomposite were studied by infrared spectroscopy (FTIR), X-ray diffraction (XRD), small angle X-ray scattering (SAXS) and scanning electron microscopy (SEM). The reaction between polyurethane oligomers with isocyanate endcapped chains and water led to the evolution of CO 2 , which was responsible for building interconnected pores with sizes ranging from 184 to 387 µm. An in vitro cell-nanocomposite interaction study was carried out using neonatal rat calvarial osteoblasts. The ability of cells to proliferate and produce an extracellular matrix in contact with the synthesized material was assessed by an MTT assay, a collagen synthesis analysis, and the expression of alkaline phosphatase. In vivo experiments were performed by subcutaneously implanting samples in the dorsum of rats. The implants were removed after 14, 21, and 29 days, and were analyzed by SEM and optical microscopy after tissue processing. Histology crosssections and SEM analyses showed that the cells were able to penetrate into the material and to attach to many location throughout the pore structure. In vitro and in vivo tests demonstrated the feasibility for polyurethane nanocomposites to be used as artificial extracellular matrices onto which cells can attach, grow, and form new tissues.

Studies on Flexible Polyurethane Foam With Improved Flame Retardancy

“…The band in this region, generally confirms the characteristics of urea and urethane groups. The same has been reported [21,22]. In the FTIR spectrum the absorbance between 2270 cm -1 -2240 cm -1 was not observed.…”

Biocompatibility of various hydoxyapatite scaffolds evaluated by proliferation of rat’s bone marrow mesenchymal stem cells: an <em>in vitro</em> study

“…Scaffold III was slightly toxic but less than scaffold I,II, and V. From our study, only scaffold IV showed inhibition of cell proliferation less than 50%, therefore, it is no longer toxic to MSCs. Dias, et al 13 stated that if there is no changes in morphology and activity of cells that were observed in cells culture in contact with scaffold/biomaterial, that scaffold is cytocompatible.…”

A Moisture‐ and Oxygen‐Impermeable Separator for Aprotic Li‐O2 Batteries

“…The structural identity of PU was verifi ed by Fourier transform infrared (FT-IR) spectroscopy (Figure 1 b); as-prepared PU separator exhibited two distinct characteristic peaks at 3330 and 1730 cm −1 assigned to the N H and C O bonds of the urethane group in the hard segment. [ 46,47 ] Most of the key properties of the PU separator were examined in comparison with commercial porous polyethylene (PE) separator. As shown in Figure 1 c, at the same magnifi cations, scanning electron microscopy (SEM) images showed clear morphology difference between them; while the PE separator showed many pores ranging from 150 to 250 nm, no pores were detected in the PU separator at all even at the high magnifi cation (see Supporting Information Figure S1 for an SEM image at ultrahigh magnifi cation).…”