Selective laser sintered nano-HA/PDLLA composite microspheres for bone scaffolds applications

Abstract

<jats:sec> <jats:title content-type="abstract-subheading">Purpose</jats:title> <jats:p>The main cause of aseptic inflammation after an <jats:italic>in vivo</jats:italic> implantation is that Poly(L-lactide) (PLLA) and Poly(D-lactide) have a slower degradation and absorption rate, while Poly(D, L-lactide) (PDLLA) has a much faster degradation rate than PLLA because of its amorphous structure. Also, the hydrolyzate of Hydroxyapatite (HA) is alkaline, which can neutralize local tissue peracid caused by hydrolysis of Polylactic acid.</jats:p> </jats:sec> <jats:sec> <jats:title content-type="abstract-subheading">Design/methodology/approach</jats:title> <jats:p>In this study, the selective laser sintering (SLS) technique was chosen to prepare bone scaffolds using nano-HA/PDLLA composite microspheres, which were prepared by the solid-in-oil-in-water (S/O/W) method. First, the SLS parameters range of bulk was determined by the result of a single-layer experiment and the optimized parameters were then obtained by the orthogonal experiment. The tensile property, hydrophobicity, biocompatibility, biological toxicity and <jats:italic>in vitro</jats:italic> degradation of the samples with optimized SLS parameters were characterized.</jats:p> </jats:sec> <jats:sec> <jats:title content-type="abstract-subheading">Findings</jats:title> <jats:p>As a result, the samples showed a lower tensile strength because of the many holes in their interior, which was conducive to better cell adhesion and nutrient transport. In addition, the samples retained their inherent properties after SLS and the hydrophobicity was improved after adding nano-HA because of the OH group. Furthermore, the samples showed good biocompatibility with the large number of cells adhering to the material through pseudopods and there was no significant difference between the pure PDLLA and 10% HA/PDLLA in terms of biological toxicity. Finally, the degradation rate of the composites could be tailored by the amount of nano-HA.</jats:p> </jats:sec> <jats:sec> <jats:title content-type="abstract-subheading">Originality/value</jats:title> <jats:p>This study combined the S/O/W and SLS technique and provides a theoretical future basis for the preparation of drug-loaded microsphere scaffolds through SLS using HA/PDLLA composites.</jats:p> </jats:sec>

In situ synthesis of hydroxyapatite nanorods on graphene oxide nanosheets and their reinforcement in biopolymer scaffold

“…According to the EDS spectra, the elements were mainly C, O, Ca and P. Meanwhile, the Ca/P ratio of the deposits increased from 1.47 to1.65 as the GO-HAP mass fraction increased from 4% to 16%, which were gradually close to the 1.67 of HAP [10] . The results revealed that the PLLA/GO-HAP scaffolds owned well bioactivity to induce bone-like apatite layer, which was vital to form a chemical bond between the implant scaffold and living bone tissue [13] , [45] . Previous studies had demonstrated that pure PLLA lacked bioactivity, therefore the well bioactivity was attributed to GO-HAP [11] .…”

“…The water contact angle of the PLLA/GO-HAP scaffolds with 4%, 8%, 12% and 16% mass fractions of GO-HAP were 74.1°, 65.9°, 58.7° and 53.6°, respectively. The decrease was ascribed to the incorporation of GO and HAP with good hydrophilicity [13] . Therefore, the scaffold presented an increase in hydrophilicity with the increasing content of GO-HAP.…”

“…Hydroxyapatite (HAP), as a calcium phosphate, possesses excellent bioactivity and osteoconductivity because of its chemical composition similarity to natural bone [9] , [10] , [11] . Meanwhile, it has been usually used as a mechanical reinforcement phase for biopolymer, while the reinforcing effect of HAP is not to be compared with that of GO resulted from its intrinsic brittleness [12] , [13] , [14] . Hence, the combination of GO and HAP will show great potential for the reinforcement of biopolymer due to their superiority in mechanical properties, bioactivity and osteoconductivity.…”

Biodegradable Microparticles for Regenerative Medicine: A State of the Art and Trends to Clinical Application

“…Indeed, native bone tissue has a complex structure both in terms of architecture and composition [ 156 ]. Still, additive technologies allow controlling scaffold’s 3D structure [ 157 , 158 , 159 ], while the usage of hybrid polymer/inorganic microparticles containing calcium phosphates mimic natural bone composition [ 160 , 161 , 162 ]. PCL powder was transformed into a porous scaffold with the aim of selective laser sintering technology, coated by collagen and used for chondrocytes culture [ 163 ].…”

Powder 3D Printing of Bone Scaffolds with Uniform and Gradient Pore Sizes Using Cuttlebone-Derived Calcium Phosphate and Glass-Ceramic

“…Many CaPs, such as hydroxyapatite (HA), β-tricalcium phosphate (β-TCP), α-TCP, biphasic HA/β-TCP, tetracalcium phosphate and octacalcium phosphate, have been used to produce scaffolds by SLS, SLA, P-3DP and DIW [ 15 , 16 ]. In the SLS process, the ceramic powders are usually blended with polymers such as PLA [ 17 ], PDLLA [ 18 ], PCL and PEEK [ 19 ] to form composite materials, in order to avoid the high operating temperatures that are required for sintering [ 10 ]. In P-3DP, SLA and DIW, instead, powders are used alone or in suspensions or pastes, with this allowing for the fabrication of pure CaPs scaffolds.…”