The Influence of Lyophilized EmuGel Silica Microspheres on the Physicomechanical Properties, In Vitro Bioactivity and Biodegradation of a Novel Ciprofloxacin-Loaded PCL/PAA Scaffold.

Mostafa Mabrouk,Yahya Choonara,Pradeep Kumar,Lisa Du Toit,Viness Pillay

doi:10.3390/polym8060232

Mostafa Mabrouk, Yahya Choonara + Show 3 more

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https://doi.org/10.3390/polym8060232

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Abstract

A new composite poly(caprolactone) (PCL) and poly(acrylic acid) (PAA) (PCL:PAA 1:5) scaffold was synthesized via dispersion of PCL particles into a PAA network. Silica microspheres (Si) (2–12 μm) were then prepared by a lyophilized micro-emulsion/sol-gel (Emugel) system using varying weight ratios. The model drug ciprofloxacin (CFX) was used for in situ incorporation into the scaffold. The physicochemical and thermal integrity, morphology and porosity of the system was analyzed by X-Ray Diffraction (XRD), Attenuated Total Refelctance Fourier Transform Infrared (ATR-FTIR), Differential Scanning Calorimetry (DSC), SEM, surface area analysis and liquid displacement, respectively. The mechanical properties of the scaffold were measured by textural analysis and in vitro bioactivity, biodegradation and pH variations were evaluated by XRD, FTIR and SEM after immersion in Simulated Body Fluid (SBF). The in vitro and in vivo studies of the prepared scaffold were considered as future aspects for this study. CFX release was determined in phosphate buffer saline (PBS) (pH 7.4; 37 °C). The incorporation of the Si microspheres and CFX into the scaffold was confirmed by XRD, FTIR, DSC and SEM, and the scaffold microstructure was dependent on the concentration of Si microspheres and the presence of CFX. The system displayed enhanced mechanical properties (4.5–14.73 MPa), in vitro bioactivity, biodegradation and controlled CFX release. Therefore, the PCL/PAA scaffolds loaded with Si microspheres and CFX with a porosity of up to 87% may be promising for bone tissue engineering.

Highlights

Poly(caprolactone) (PCL) is an aliphatic polyester that has been widely used in the biomedical field and for drug delivery applications due to its well-known properties such as biocompatibility, low immunogenicity, permeability and degradation products of low acidity compared with other aliphatic polyesters [1,2]
Upon the silica microspheres loading into the PCL/poly(acrylic acid) (PAA) blend scaffold, the pores smooth pore walls
%) are recommended for a concentrations are recommended for a sustained and prolonged due to silica their sustained and prolonged CFX release due to their relatively low porosity comparedrelease with the low relatively low porosity compared with the low silica microspheres concentrations

Summary

Introduction

Poly(caprolactone) (PCL) is an aliphatic polyester that has been widely used in the biomedical field and for drug delivery applications due to its well-known properties such as biocompatibility, low immunogenicity, permeability and degradation products of low acidity compared with other aliphatic polyesters [1,2]. PCL is hydrophobic, has a relatively high crystallinity and is inflexible in terms of chemical interaction This limits its use in biomedical applications such as for bone tissue engineering. The complexation of PCL with other biocompatible polymers has shown promise in expanding the applications of PCL in tissue engineering [3,4] Polyanionic macromolecules such as poly(acrylic acid) (PAA) have been broadly investigated as an organic substrate for the production of calcium carbonate particles via electrostatic interaction between the carboxyl groups and calcium ions in solution [5,6]. This introduces a new approach for organic–inorganic composite synthesis with superior performance as a biomaterial. Si is a well-known matrix for microsphere preparation due to its chemical inertia, low density, high thermal and mechanical stability as well as ease of functionalization [7,8]

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