Aligned core/shell electrospinning of poly(glycerol sebacate)/poly(l‐lactic acid) with tuneable structural and mechanical properties

In an earlier study, scaffolds of biodegradable poly(glycerol sebacate) (PGS)/poly(l ‐lactic acid) (PLLA) core/shell fibres had been fabricated using a core/shell electrospinning method, and the scaffolds were found to have mechanical properties similar to those of natural soft tissues, excellent cytocompatibility and slow degradation rate. In this paper, PGS/PLLA core/shell fibre mats with tuneable degrees of fibre alignment were fabricated using core/shell electrospinning with a rotating fibre collection mandrel. An increase in the rotational speed raised the degree of fibre alignment in the fibre mats. Single and cyclic tensile testing of the mats showed that an increase in the fibre alignment raised the modulus, resilience, ultimate tensile strength (UTS) and elongation up to a maximum at 1000 or 1500 rpm, but the resilience, UTS and elongation decreased when the rotational speed was further raised to 2000 rpm. Nonlinearly elastic biomaterials with a large range of mechanical properties were successfully fabricated using this method and the aligned fibre structure may be capable of guiding the growth of attached cells. © 2016 Society of Chemical Industry     

The influence of the preparation conditions and filler content on thermal properties of poly‐l‐lactide and hydroxyapatite/poly‐l‐lactide nanocomposite

Poly‐l ‐lactide (PLLA) and hydroxyapatite/poly‐l ‐lactide (HAp/PLLA) are two widely used biomaterials for three‐dimensional scaffolds, drug release matrices and implantable medical devices for reparation of bone tissue; diversity in the initial preparation and filler content has a significant influence on different properties such as morphology and crystallinity, thus playing a considerable role in most of these applications. For this reason, PLLA and HAp/PLLA samples with a large difference in crystallinity (from below 20% to over 70%) and filler content (up to 86 wt% of HAp nanoparticles with an average diameter of 80 nm) were prepared and consequent dissimilarities in morphology, crystallinity and thermal properties were investigated by scanning electron microscopy (SEM), differential scanning calorimetry (DSC), wide angle X‐ray diffraction (WAXD) measurements and Fourier transform infrared (FTIR) spectroscopy. Special attention was devoted to analyzing data obtained from thermal measurements. A three‐phase model was employed in order to describe the heat capacity step decline in the nanocomposite; the evolution in different polymer fractions, the crystalline fraction and the mobile and rigid amorphous fractions, with filler content was determined. © 2017 Society of Chemical Industry     

Electrospun poly(l-lactic acid) fiber mats containing crude Garcinia mangostana extracts for use as wound dressings

Poly(l-lactic acid) (PLLA) fiber mats containing two types of crude Garcinia mangostana Linn. (GM) extract [i.e., dichloromethane extract (dGM) and acetone extract (aGM)] were successfully prepared by electrospinning process. Both the neat and the GM-loaded PLLA fibers were smooth, with the average diameters ranging between 0.77 and 1.14 μm. The release characteristics of GM from the GM-loaded PLLA fiber mats were carried out by total immersion method in acetate buffer or simulated body fluid that contained 0.5 % v/v Tween 80 and 3 % v/v methanol (hereafter, A/T/M or S/T/M medium) at either 32 or 37 °C, respectively. The maximum cumulative amounts of GM released from the GM-loaded PLLA fiber mats in the S/T/M medium were greater than those in the A/T/M medium. Moreover, the cumulative amounts of GM released from the aGM-loaded PLLA fiber mats were greater than those from the dGM-loaded PLLA fiber mats in both types of medium. The antibacterial activity of the dGM-loaded PLLA fiber mats was greatest against Staphylococcus aureus DMST 20654, while that of the aGM-loaded PLLA fiber mats was greatest against S. aureus ATCC 25923 and S. epidermidis. Lastly, only the dGM-loaded PLLA fiber mats at extraction ratio of 10 mg mL^?1 were toxic to the human dermal fibroblasts.     

Preparation and characterization of Chitosan and PLGA‐based scaffolds for tissue engineering applications

Three dimensional (3D) biodegradable porous scaffolds play a crucial role in bone tissue repair. In this study, four types of 3D polymer/hydroxyapatite (HAp) composite scaffolds were prepared by freeze drying technique in order to mimic the organic/inorganic nature of the bone. Chitosan (CH) and poly(lactic acid‐co‐glycolic acid) (PLGA) were used as the polymeric part and HAp as the inorganic component. Properties of the resultant scaffolds, such as morphology, porosity, degradation, water uptake, mechanical and thermal stabilities were examined. 3D scaffolds having interconnected macroporous structure and 77–89% porosity were produced. The pore diameters were in the range of 6 and 200 µm. PLGA and HAp containing scaffolds had the highest compressive modulus. PLGA maintained the strength by decreasing water uptake but increased the degradation rate. Scaffolds seeded with SaOs‐2 osteoblast cells showed that all scaffolds were capable of encouraging cell adhesion and proliferation. The presence of HAp particles caused an increase in cell number on CH‐HAp scaffolds compared to CH scaffolds, while cell number decreased when PLGA was incorporated in the structure. CH‐PLGA scaffolds showed highest cell number on days 7 and 14 compared to others. Based on the properties such as interconnected porosity, high mechanical strength, and in vitro cell proliferation, blend scaffolds have the potential to be applied in hard tissue treatments. POLYM. COMPOS., 36:1917–1930, 2015. © 2014 Society of Plastics Engineers     

Electrospun 1,6-diisocyanatohexane-extended poly(1,4-butylene succinate) fiber mats and their potential for use as bone scaffolds

Ultrafine 1,6-diisocyanatohexane-extended poly(1,4-butylene succinate) (PBSu-DCH) fibers were best fabricated by electrospinning from 22% w/v PBSu-DCH solution in 90:10 v/v dichloromethane/trifluoroacetic acid under the electric field of 17 kV/20 cm. The diameters of these fibers were 172 ± 3 nm. Due to their fibrous nature, the obtained PBSu-DCH fiber mats exhibited high values of advancing/receding water contact angles (i.e., 114°/79°) and porosity (69%). Indirect cytotoxicity evaluation of the PBSu-DCH fiber mats based on the viabilities of human osteosarcoma cells (SaOS-2) and mouse fibroblasts (L929) revealed that the fibrous materials did not release any substance in the level that was harmful to the cells. The potential for use of the PBSu-DCH fiber mats as substrates for bone cell culture was further evaluated in vitro with SaOS-2 in terms of the ability to support the attachment and to promote the proliferation and the differentiation of the seeded/cultured cells. Comparative studies were made against corresponding solvent-cast PBSu-DCH films. The results indicated that the bone cells grown on the surface of the fiber mats could attach, proliferate and express alkaline phosphatase (ALP), an early osteogenic proliferation marker, better than they did on the surface of the films. The evidence obtained in this work implies the potential for use of the electrospun PBSu-DCH fiber mats as bone scaffolds.     

Bone scaffolds from electrospun fiber mats of poly(3-hydroxybutyrate), poly(3-hydroxybutyrate-co-3-hydroxyvalerate) and their blend

In the present contribution, electrospinning was used to fabricate ultrafine fiber mats from poly(3-hydroxybutyrate) (PHB), poly(3-hydroxybutyrate-co-2-hydroxyvalerate) (PHBV), and their 50/50 w/w blend for potential use as bone scaffolds. Cytotoxicity evaluation of these as-spun fiber mats with human osteoblasts (SaOS-2) and mouse fibroblasts (L929) indicated biocompatibility of these materials to both types of cells. The potential for use of these fiber mats as bone scaffolds was further assessed in vitro in terms of the attachment, the proliferation, and the alkaline phosphatase (ALP) activity of SaOS-2 that were seeded or cultured at different times. The cells appeared to adhere well on all types of the fibrous scaffolds after 16 h of cell seeding. During the early stage of the proliferation period (i.e., from ∼24 to 72 h in culture), the viability of the cells increased considerably and appeared to be unchanged with further increase in the time in culture. In comparison with the corresponding solution-cast film scaffolds, all of the fibrous scaffolds exhibited much better support for cell attachment and proliferation. Lastly, among the various fibrous scaffolds investigated, the electrospun fiber mat of the 50/50 w/w PHB/PHBV blend showed the highest ALP activity. These results implied a high potential for use of these electrospun fiber mats as bone scaffolds.     

Crystallization kinetics of poly(L‐lactide)/carbonated hydroxyapatite nanocomposite microspheres

Microspheres consisting of carbonated hydroxyapatite (CHAp) nanoparticles and poly(L ‐lactide) (PLLA) have been fabricated for use in the construction of osetoconductive bone tissue engineering scaffolds by selective laser sintering (SLS). In SLS, PLLA polymer melts and crystallizes. It is therefore necessary to study the crystallization kinetics of PLLA/CHAp nanocomposites. The effects of 10 wt% CHAp nanoparticles on the isothermal and nonisothermal crystallization behavior of PLLA matrix were studied, using neat PLLA for comparisons. The Avrami equation was successfully applied for the analysis of isothermal crystallization kinetics. Using the Lauritzen‐Hoffman theory, the transition temperature from crystallization Regime II to Regime III was found to be around 120°C for both neat PLLA and PLLA/CHAp nanocomposite. The combined Avrami‐Ozawa equation was used to analyze the nonisothermal crystallization process, and it was found that the Ozawa exponent was equal to the Avrami exponent for neat PLLA and PLLA/CHAp nanocomposite, respectively. The effective activation energy as a function of the relative crystallinity and temperature for neat PLLA and PLLA/CHAp nanocomposite under the nonisothermal crystallization condition was obtained by using the Friedman differential isoconversion method. The Lauritzen‐Hoffman parameters were also determined from the nonisothermal crystallization data by using the Vyazovkin‐Sbirrazzuoli equation. CHAp nanoparticles in the composite acted as an efficient nucleating agent, enhancing the nucleation rate but at the same time reducing the spherulite growth rate. This investigation has provided significant insights into the crystallization behavior of PLLA/CHAp nanocomposites, and the results obtained are very useful for making good quality PLLA/CHAp scaffolds through SLS. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Preparation of Pure PLLA,Pure Chitosan,and PLLA/Chitosan Blend Porous Tissue Engineering Scaffolds by Thermally Induced Phase Separation Method and Evaluation of the Corresponding Mechanical and Biological Properties

The aim of this work was to prepare the scaffolds of pure poly (L-lactic acid) 3% (w/v), pure chitosan 3% (w/v), and PLLA/chitosan blend (1:5) 3% (w/v) using TIPS method and investigate their properties and application in tissue engineering. An in vitro degradation study of scaffolds showed the addition of chitosan to PLLA not only increased its degradation rate, but also slowed down its pH value reduction. Addition of chitosan to PLLA increased hydrophilicity, porosity, compressive properties, and cell viability of the scaffolds. The results indicate that among all scaffolds, the most appropriate candidate for tissue engineering is PLLA/chitosan blend.     

Preparation and characterization of poly(L‐lactide)/ poly(ϵ‐caprolactone) fibrous scaffolds for cartilage tissue engineering

Polyblend fibrous scaffolds in mass ratios of 100/0, 90/10, 80/20, and 70/30 from poly(L ‐lactide) (PLLA) and poly(?‐caprolactone) (PCL) for cartilage tissue engineering were prepared in three steps: gelation, solvent exchanging, and freeze‐drying. Effects of the blend ratio, the exchange medium, and the operating temperature on the morphology of scaffolds were investigated by SEM. PLLA/PCL scaffolds presented an ultrafine fibrous network with the addition of a “small block” structure. Smooth and regular fibrous networks were formed when ethanol was used as the exchange medium. Properties of the scaffolds, such as thermal and mechanical properties, were also studied. The results suggested that the compressive modulus declined as PCL amount increased. The incorporation of PCL effectively contributed to reduce the rigidity of PLLA. Bovine chondrocytes were seeded onto PLLA/PCL scaffold. Cells attached onto the fibrous network and their morphology was satisfactory. This polyblend fibrous scaffold will be a potential scaffold for cartilage tissue engineering. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1676–1684, 2004     

Highly filled poly(l-lactic acid)/hydroxyapatite composite for 3D printing of personalized bone tissue engineering scaffolds

The designing of new biodegradable polymer composites is one of the most promising areas of modern orthopedics and regenerative surgery. At present, a number of methods have been proposed for designing and processing biodegradable polymer composites via various 3D printing technologies; however, the homogeneity of filler distribution together with mechanical properties of scaffolds made of such composites are far from those required for clinical use. In this study, the method for producing biodegradable composite material based on poly(l -lactic acid) (PLLA) solution in organic solvent and hydroxyapatite (HAp) powder was proposed. The influence of HAp weight fraction and additional annealing on PLLA matrix crystallinity was investigated. It was shown that crystallinity of PLLA decreases from 58.84 ± 1.21 to 17.33 ± 1.69 as HAp weight fraction increased from 0 to 50 wt%. However, HAp filler promoted PLLA crystallites growth according to the X-ray powder diffraction analysis. The results of nanoindentation showed Young's modulus values of the 3D-printed scaffolds with 50 wt% of HAp at the level of human femur and tibia.     

Thermomechanical properties of poly(lactic acid) films reinforced with hydroxyapatite and regenerated cellulose microfibers

Novel composite films constituted of poly(lactic acid) (PLA), hydroxyapatite (HAp), and two types of regenerated cellulose fillers—particulate and fibrous type—were produced by melt extrusion in a twin‐screw micro‐compounder. The effect of the film composition on the tensile and dynamic mechanical behavior and the HAp dispersion in the PLA matrix were investigated thoroughly. Appearance of crazed regions and prevention of HAp aggregation in the PLA matrix were elucidated in the composites with up to 15 wt % particulate cellulose content, which was the main reason for only slight reduction in the tensile properties, and consequently trivial degradation of their pre‐failure energy absorption as compared to neat PLA films. Superior dynamical energy storage capacities were obtained for the particulate cellulose modified composites, while their fibrous counterparts had not as good properties. Additionally, the anisotropic mechanical behavior obtained for the extruded composites should be favorable for use as biomaterials aimed at bone tissue engineering applications. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40911.     

Development of Electrospun Composite Fibers in Multiscale Structure and Investigating the Performance on Proliferation and Osteogenic Differentiation of ADSCs

Electrospun composite membranes in multiscale structures are developed for bone tissue engineering. Aligned polycaprolactone (PCL) fibers entrapping CA‐HAp microparticles (containing CaCO₃, hydroxyapatite, and casein in a hierarchical organization) are electrospun to find whether synergistic effects of fiber alignment and CA‐HAp microparticles on improving osteogenic differentiation can be obtained. CA‐HAp microparticles are in a spherical morphology of 1.42 ± 0.26 µm. Their presence increases fiber diameter and does not significantly affect fiber alignment. On all membranes, adipose derived stem cells (ADSCs) from humans spread very well. On a random group, cells distribute randomly and the presence of CA‐HAp microparticles facilitates cell proliferation, especially for the one at CA‐HAp/PCL 50 wt%; the one at CA‐HAp/PCL 20 wt% shows significantly much higher alkaline phosphatase (ALP) activity (112.0% higher) than the pure PCL membrane. On aligned samples, cells align along fibers and expression of ALP is enhanced. However, at the same composition (CA‐HAp/PCL 20 wt%), the random sample has much higher ALP activity than the aligned sample. The expressions of osteogenic marker genes are also evaluated. Combining the results and the applicability of membranes together, the random membrane at CA‐HAp/PCL 20 wt% is the best candidate for bone tissue engineering.     

Protein expression by bone mesenchymal stem cells cultivated in PLLA scaffolds with different pore geometry

Abstract

The effects of poly(L,L-lactide) (PLLA) scaffold with axial and isotropic structure were investigated on functional activity of rabbit bone mesenchymal stem cells (BMSCs). PLLA scaffolds were processed by freeze-dry technique at different temperatures of the scaffold frost – ?196?°C, ?25?°C and 0?°C. Scaffolds with different pore sizes were obtained by adding 5 or 10% of water phase. Scaffolds were modified by collagen type I solution. The pore sizes of polymer scaffolds were ranging from 5 to 150?µm. More protein secretion was observed in the surface-modified scaffolds than in the unmodified after 2 weeks of cultivation in vitro.     

Aligned unidirectional PLA/bacterial cellulose nanocomposite fibre reinforced PDLLA composites

In an effort to enhance the properties of polylactide (PLA), we have developed melt-spinning techniques to produce both PLA/nanocellulose composite fibres, and a method akin to layered filament winding followed by compression moulding to produce self-reinforced PLA/nanocellulose composites. Poly(L-lactide) (PLLA) fibres were filled with 2 wt.% neat and modified bacterial cellulose (BC) in an effort to improve the tensile properties over neat PLA fibres. BC increased the viscosity of the polymer melt and reduced the draw-ratio of the fibres, resulting in increased fibre diameters. Nonetheless, strain induced chain orientation due to melt spinning led to PLLA fibres with enhanced tensile modulus (6 GPa) and strength (127 MPa), over monolithic PLLA, previously measured at 1.3 GPa and 61 MPa, respectively. The presence of BC also enhanced the nucleation and growth of crystals in PLA. We further produced PLA fibres with 7 wt.% cellulose nanocrystals (CNCs), which is higher than the percolation threshold (equivalent to 6 vol.%). These fibres were spun in multiple, alternating controlled layers onto spools, and subsequently compression moulded to produce unidirectional self-reinforced PLA composites consisting of 60 vol.% PLLA fibres reinforced with 7 wt.% CNC in a matrix of amorphous PDLLA, which itself contained 7 wt.% of CNC. We observed improvements in viscoelastic properties of up to 175% in terms of storage moduli in bending. Furthermore, strains to failure for PLLA fibre reinforced PDLLA were recorded at 17%.     

Wetting behaviour and direct observation of thermally responsive polystyrene‐block‐poly(N‐isopropylacrylamide)‐block‐polystyrene electrospun fibres in aqueous environment

Electrospun fibres of thermally responsive triblock copolymer polystyrene‐block‐poly(N‐isopropylacrylamide)‐block‐polystyrene were prepared. Fibre morphology and swelling were studied below and above the lower critical solution temperature of poly(N‐isopropylacrylamide) (PNIPAM) using cryo‐electron microscopy. Cryo‐transmission electron microscopy showed that the fibre diameter increased up to 150% after immersion in water at 20 °C. In contrast, at 45 °C the fibre diameter increased considerably less. The sessile drop technique was used to characterize temperature‐dependent wetting of fibre mats. Contact angle (θ_CA) measurements revealed that a block copolymer fibre mat changed from hydrophobic (θ_CA > 90°) to hydrophilic (θ_CA < 90°) state within seconds after applying a water droplet on it at 20 °C. At 40 °C the initial contact angle was measured to be higher (135°) and it decreased much less than at 20 °C during the first minute of measurement. We observed using scanning electron microscopy that the electrospun fibres of the block copolymer having 77 wt% of PNIPAM lost their cylindrical shape and changed from fibres to thin sheets at both 20 and 40 °C within seconds after applying water on the fibres. Fibres having 55 wt% of PNIPAM were observed to be stable in water at both 20 and 40 °C, which resulted, surprisingly, in fibre mats with the strongest effects on thermally sensitive wetting. We discuss the surprising results and the implications that the evolution of fibre surface roughness has on the long‐term wetting behaviour, demonstrating a self‐adaptable hydrophilicity/hydrophobicity nature of the fibre mats. © 2013 Society of Chemical Industry     

A Solvent‐Assisted Compression Molded of Poly(L‐lactide)/Hydroxyapatite Electrospun Fibers for Robust Engineered Scaffold Systems

In an attempt to enhance the biocompatibility and mechanical strength of fibrous polymeric scaffold systems, nanocrystalline hydroxyapatite (HAp) particles were incorporated into the electrospun poly(L ‐lactide) (PLLA) fibers and then mechanically interlocked using a vapor‐phase solvent adsorption method. The solvent‐assisted compression molding substantially increased the tensile strength (from 4.61 to 12.63 MPa) and mechanical modulus (from 50.6 to 627.7 MPa) of the fibrous scaffold, which maintained the interstitial space between the fibers to allow the facile transport of nutrients and waste during cell growth and polymer biodegradation. Macrometer‐sized pores (ca. 100–400 µm) were introduced into the scaffolds in a controlled fashion using the salt leaching/gas forming technique to give desired space for a facile cell implantation and growth. Overall, the developed methodology allows the polymer‐based scaffold systems to be tailored for various applications in light of surface characteristics, mechanical strength, and pore size of engineered scaffolds.

     

Influence of hydroxyapatite and BMP‐2 on bioactivity and bone tissue formation ability of electrospun PLLA nanofibers

An excellent bioactive scaffold material which could induce and promote new bone formation is essential in the bone repair field. In this study, the bioactive material hydroxyapatite (HA) and the bone morphogenetic protein‐2 (BMP‐2) were added to poly‐l‐lactic acid (PLLA) using the electrospinning method. Scanning electron microscopy investigations performed on four different fiber scaffolds, PLLA, PLLA/HA, PLLA/BMP‐2 and PLLA/HA/BMP‐2, revealed that the fibers of all scaffolds are closely interwoven, and the presence of large interconnected voids between the fibers, resulting in a three‐dimensional porous network structure that was similar to the structure of the extracellular matrix of healthy bones. In the MG63 cell culture growth experiments, the composite scaffold material PLLA/HA/BMP‐2 showed a higher bioactivity than the other three scaffold materials. The four scaffold materials were implanted in rabbits’ tibia for 30 and 90 days. The results of the animal experiments indicate that the capability of the PLLA/HA/BMP‐2 composite to induce and promote bone tissue formation was better compared with PLLA/HA or PLLA/BMP‐2, suggesting that PLLA combined with HA/BMP‐2 is a promising material for bone tissue repair. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42249.     

Fabrication and characterization of electrospun poly‐DL‐lactide (PDLLA) fibrous coatings on 45S5 Bioglass® substrates for bone tissue engineering applications

BACKGROUND: This work focuses on combining electrospun biodegradable poly‐DL‐lactide (PDLLA) fibres and 45S5 Bioglass^® for tissue engineering applications. RESULTS: A variety of fibrous structures were produced upon application of an electric field to a flowing solution of PDLLA (5 wt/v%) in di‐methyl carbonate (DMC). Electrospinning was achieved at an applied voltage of 8.5 kV for a fixed flow rate of 5 µL min^?1. Scanning electron microscopy images of PDLLA fibres deposited on 45S5 Bioglass^® sintered pellets revealed that the fibres had diameters in the range 100–200 nm, leading to increased surface roughness, as assessed by white light interferometry. Bioactivity studies on PDLLA fibre coated Bioglass^® substrates were carried out in simulated body fluid (SBF) for 7, 14 and 28 days. It was found that mineralization of PDLLA fibres on 45S5 Bioglass^® substrate (formation of hydroxyapatite) occurred after 7 days of immersion in SBF and full coverage of PDLLA fibres with HA nanocrystals was achieved after 14 days in SBF. CONCLUSION: The approach investigated represents a convenient method to develop a controlled mineralized fibrous topography on bioactive glass substrates for improved cell attachment, which can be exploited in bone tissue engineering applications. Copyright © 2009 Society of Chemical Industry     

Application of low loading of collagen in electrospun poly[(l‐lactide)‐co‐(ε‐caprolactone)] nanofibrous scaffolds to promote cellular biocompatibility

Electrospinning of various polymers has been used to produce nanofibrous scaffolds that mimic the extracellular matrix and support cell attachment for the potential repair and engineering of nerve tissue. In the study reported here, an electrospun copolymer of l ‐lactide and ε‐caprolactone (67:33 mol%) resulted in a nanofibrous scaffold with average fibre diameter and pore size of 476 ± 88 and 253 ± 17 nm, respectively. Blending with low loadings of collagen (<2.5% w/w) significantly reduced the average diameter and pore size. The uniformity of fibre diameter distributions was supported with increasing collagen loadings. The nanofibrous scaffolds significantly promoted the attachment and proliferation of olfactory ensheathing cells compared to cells exhibiting asynchronous growth. Furthermore, analysis of cell health through mitochondrial activity, membrane leakage, cell cycle progression and apoptotic indices showed that the nanofibrous membranes promoted cell vigour, reducing necrosis. The study suggests that the use of more cost‐effective, low loadings of collagen supports morphological changes in electrospun poly[(l ‐lactide)‐co‐(ε‐caprolactone)] nanofibrous scaffolds, which also support attachment and proliferation of olfactory ensheathing cells while promoting cell health. The results here support further investigation of the electrospinning of these polymer blends as conduits for nerve repair. © 2013 Society of Chemical Industry     

Direct ink writing of vancomycin-loaded polycaprolactone/ polyethylene oxide/ hydroxyapatite 3D scaffolds

Novel inks were formulated by dissolving polycaprolactone (PCL), a hydrophobic polymer, in organic solvent systems; polyethylene oxide (PEO) was incorporated to extend the range of hydrophilicity of the system. Hydroxyapatite (HAp) with a weight ratio of 55–85% was added to the polymer-based solution to mimic the material composition of natural bone tissue. The direct ink writing (DIW) technique was applied to extrude the formulated inks to fabricate the predesigned tissue scaffold structures; the influence of HAp concentration was investigated. The results indicate that in comparison to other inks containing HAp (55%, 75%, and 85%w/w), the ink containing 65% w/w HAp had faster ink recovery behavior; the fabricated scaffold had a rougher surface as well as better mechanical properties and wettability. It is noted that the 65% w/w HAp concentration is similar to the inorganic composition of natural bone tissue. The elastic modulus values of PCL/PEO/HAp scaffolds were in the range of 4–12 MPa; the values were dependent on the HAp concentration. Furthermore, vancomycin as a model drug was successfully encapsulated in the PCL/PEO/HAp composite scaffold for drug release applications. This paper presents novel drug-loaded PCL/PEO/HAp inks for 3D scaffold fabrication using the DIW printing technique for potential bone scaffold applications.