Influence of Hydroxyapatite Surface Functionalization on Thermal and Biological Properties of Poly(l-Lactide)- and Poly(l-Lactide-co-Glycolide)-Based Composites

Abstract

Novel biocomposites of poly(L-lactide) (PLLA) and poly(l-lactide-co-glycolide) (PLLGA) with 10 wt.% of surface-modified hydroxyapatite particles, designed for applications in bone tissue engineering, are presented in this paper. The surface of hydroxyapatite (HAP) was modified with polyethylene glycol by using l-lysine as a linker molecule. The modification strategy fulfilled two important goals: improvement of the adhesion between the HAP surface and PLLA and PLLGA matrices, and enhancement of the osteological bioactivity of the composites. The surface modifications of HAP were confirmed by attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), TGA, and elemental composition analysis. The influence of hydroxyapatite surface functionalization on the thermal and in vitro biological properties of PLLA- and PLLGA-based composites was investigated. Due to HAP modification with polyethylene glycol, the glass transition temperature of PLLA was reduced by about 24.5 °C, and melt and cold crystallization abilities were significantly improved. These achievements were scored based on respective shifting of onset of melt and cold crystallization temperatures and 1.6 times higher melt crystallization enthalpy compared with neat PLLA. The results showed that the surface-modified HAP particles were multifunctional and can act as nucleating agents, plasticizers, and bioactive moieties. Moreover, due to the presented surface modification of HAP, the crystallinity degree of PLLA and PLLGA and the polymorphic form of PLLA, the most important factors affecting mechanical properties and degradation behaviors, can be controlled.

The Effect of Pore Size Distribution and l-Lysine Modified Apatite Whiskers (HAP) on Osteoblasts Response in PLLA/HAP Foam Scaffolds Obtained in the Thermally Induced Phase Separation Process

“…The l -lysine content on the surface of HAP reached 2.23 wt %; less than 10% of the amount of l -lysine taken in the modification procedure has been attached. These results agree with our previous results of the modification of nanohydroxyapatite particles [ 16 ].…”

“…Bioresorbable polymer composites can be prepared in several ways, including melt mixing–extrusion [ 13 , 15 ] and solvent techniques: solution casting [ 16 ] electrospinning [ 17 , 18 ], and thermally induced phase separation (TIPS) [ 18 , 19 , 20 ]. The last of these techniques enables one to prepare composites in the form of a foam, which can be used as the so-called scaffold that stimulates bone cells to grow on its surface [ 21 , 22 ].…”

Composites Based on Hydroxyapatite and Whey Protein Isolate for Applications in Bone Regeneration

“…Then, THP1-Blue™ NF-κB monocytes were re-cultured in selective RPMI 1640 medium additionally containing 10 µg/mL blasticidin in a density below 1 × 10 6 cells/mL at 37 °C, and in a humidified atmosphere containing 5% CO 2 . The experiments were conducted as described previously [ 32 , 33 ]. Briefly, monocytes were adjusted to the optimal density (1 × 10 6 cells/mL) and distributed equally in each well of the 96-well plate (200 µL/well).…”

“…conducted as described previously [32,33]. Briefly, monocytes were adjusted to the optimal density (1 × 10 6 cells/mL) and distributed equally in each well of the 96-well plate (200 µL/well).…”

Polymeric Scaffolds: Design, Processing, and Biomedical Application

“…Most of the articles deal with biomimetic composite scaffolds for bone tissue engineering and regeneration. The scaffolds can be made of resorbable aliphatic polyesters and inorganic mineral phase [ 3 , 4 , 5 ], hydrogels of natural origin, e.g., collagen/chitosan [ 6 ], chitosan [ 7 ], gelatin [ 8 ] or hydrogels of synthetic origin based on modified poly(vinyl alcohol) [ 9 , 10 ]. Kopeć et al [ 11 ] explore a polydopamine coating on the polyurethane surface in order to improve the mechanical properties of the obtained biomaterials, to reduce their hydrophobicity and to enhance the cell adhesion.…”