Hydrolytic degradation and cytotoxicity of poly(lactic-co-glycolic acid)/multiwalled carbon nanotubes for bone regeneration

Biodegradable poly(l -lactide-co-glycolide) (PLGA)/multiwalled carbon nanotubes (MWCNTs) scaffolds produced by thermally induced phase separation (TIPS) are studied for bone regeneration. Their magnetic properties, cytotoxicity, and in vitro degradation are investigated. Certain properties are analyzed at 37 °C over 16 weeks in phosphate buffer saline (PBS) solution, as a function of degradation time: morphology, mass loss, pH value of PBS, and thermal behavior. The presence of small quantities of nanotubes in the scaffolds, ≤0.5 wt %, leads to a weak magnetic response although the PLGA was diamagnetic. The incorporation of MWCNTs in the scaffolds generated a morphology and a very different process of in vitro degradation than might be expected in a PLGA scaffold. The in vitro degradation process started on week 13 and rapidly advanced, although the structural integrity of the scaffolds was maintained and no collapse of the structure occurred. Cytotoxicity tests on the samples showed cytotoxicity behavior at concentrations of over 0.3 wt % MWCNTs. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48439.     

Investigation of mechanical properties of porous composite scaffolds with tailorable degradation kinetics after in vitro degradation using digital image correlation

Tissue engineering combines artificial scaffolds and living cells in order to reconstruct damaged tissues and organs. The biodegradable scaffolds should maintain their mechanical properties during first stages of the regeneration. The aim of this study was to investigate the extent the degradation affects the mechanical stability of novel biodegradable composite scaffolds in relation to their composition. The scaffolds were made using fused deposition modeling. They were composed of ternary composites containing poly(ε‐caprolactone) (PCL), 5 wt% of tricalcium phosphate (TCP) and 5, 15, and 25 wt% of poly(lactide‐co‐glycolide) (PLGA). Scaffolds made of pristine PCL and binary composite PCL–TCP were tested as reference samples. The degradation experiment was carried out in simulated body fluid at 37°C for 12 weeks. Mechanical tests were carried out in a mechanical tester. Strain was measured using digital image correlation and crossbar displacement. Chemical composition had a significant effect on initial mechanical properties and their changes during degradation. The initial apparent Young's modulus of ternary composite scaffolds was two times higher than that of PCL–TCP. Higher PLGA concentration yielded faster decrease of the mechanical properties. At the end of the experiment, there were no significant differences of the modulus among all tested materials although degradation of the ternary composite scaffolds was significantly advanced. POLYM. COMPOS., 38:2402–2410, 2017. © 2015 Society of Plastics Engineers     

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     

Formation of porous PLGA scaffolds by a combining method of thermally induced phase separation and porogen leaching

A novel method for the fabrication of porous poly(L -lactide-co-glycolide) (PLGA) scaffolds by combining thermally induced phase separation and porogen leaching is presented in this article. Big pores with about 75–400 μm diameters in the obtained scaffolds were generated by the porogen, sucrose particles, while small pores with diameters less than 20 μm induced via phase separation. Extraction of the solvent, chloroform by ethanol at cool temperatures could reduce the scaffold toxicity. Effects of PLGA concentration, freezing temperature, volume fraction of porogen, and introduction of β-tricalcium phosphate (β-TCP) on morphology, porosity, and compressive properties of the scaffolds were systematically discussed. Results showed that the size of small pores decreased by decreasing the polymer concentration and reducing the freezing temperature, whereas the interconnectivity of the scaffolds was improved by increasing the porogen fraction. The compressive modulus and strength were significantly lowered by increasing the scaffold porosity, that is, by increasing porogen fraction, or decreasing the polymer concentration, or reducing the freezing temperature. Addition of β-TCP into the scaffolds did not influence the compressive modulus significantly but tended to decrease the compressive strength. The obtained scaffolds with diverse pore sizes would be potentially used in bone tissue engineering. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Poly(Lactic Acid)-Based Blends With Tailored Physicochemical Properties for Tissue Engineering Applications: A Case Study

Binary blends of poly(L-lactic) acid (PLLA: 201790 Da) and poly(lactide-co-glycolide) (PLGA) (LA:GA = 50:50 mol:mol; 32030 Da) with various compositions were prepared. Physicochemical properties of PLLA/PLGA blends were analyzed. Blends showed a biphasic morphology, with distinct glass transition temperatures, which only slightly approximated compared to pure polymers. Analysis of tensile mechanical properties through the Kerner-Uemura-Takayanagi model showed compatibility for PLLA/PLGA 75/25 blend. Rapid degradation of PLGA phase (2–8 weeks) in PLLA/PLGA 75/25 blend led to porous samples, which appear promising for drug delivery and tissue engineering. A limited inflammatory reaction resulted from subcutaneous implantation of PLLA/PLGA 75/25 in Balb-c mice.     

Silver nanoparticle incorporated poly(l‐lactide‐co‐glycolide) nanofibers: Evaluation of their biocompatibility and antibacterial properties

The objective of this work is the fabrication of poly(l ‐lactide‐co‐glycolide) or PLGA (with LA/GA ratios of 50/50 and 75/25) nanofibers containing silver nanoparticles (AgNPs) by the method of electrospinning. The incorporation of AgNPs in PLGA was carried out in three different concentrations (1, 3, 6 w/w %).The electrospun nanofibers were evaluated for their morphology by scanning electron microscopy and their fiber diameters ranged between 487 and 781 nm. Integration of AgNPs within the fibers was verified by spectroscopy studies, while the mechanical properties of the developed fibers were found comparable to the mechanical properties of the human skin. Proliferation of human dermal fibroblasts (HDF) demonstrated minimal cytotoxicity on fibers containing 1 wt % and 3 wt % of AgNPs, while 6 wt % of AgNPs inhibited cell proliferation. Antimicrobial activity was studied using three different strains of Gram‐positive and Gram‐negative bacteria. Results of the HDF proliferation and antimicrobial studies showed that the electrospun PLGA75/25 containing 3 wt % AgNP can function as a suitable substrate for wound dressing, compared to the other scaffolds of this study. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42686.     

Sustained release of dexamethasone from drug‐loading PLGA scaffolds with specific pore structure fabricated by supercritical CO2 foaming

Inducing differentiation of bone marrow stem cells to generate new bone tissue is highly desirable by controlling the release of some osteoinductive or osteoconductive factors from porous scaffolds. In this study, dexamethasone was selected as a representative of small molecule drugs and dexamethasone‐loading porous poly(lactide‐co‐glycolide) (PLGA) scaffolds were successfully fabricated by supercritical CO₂ foaming. Scanning electron microscopy images showed that scaffolds had rough and relatively interconnected pores facilitating cells adhesion and growth. Specially, dexamethasone which was incorporated into PLGA matrix in a molecularly dispersed state could serve as a nucleation agent to be helpful for the formation of interconnected pores. Dexamethasone‐loading porous PLGA scaffolds exhibited sustained release profile, and the delivery of dexamethasone from porous scaffolds could last for up to 2 months. The cumulative released amount of dexamethasone was relevant with drug loading capacity (1.66%–2.95%) and pore structure of scaffolds; while the release behavior was anomalous (non‐Fickian) transport by fitting with the simple exponential equation, which had a diffusional exponent n higher than 0.5. It is feasible to fabricate drug‐loading porous scaffolds by supercritical CO₂ foaming with specific pore structure and sustained release profile, which can be well applied in bone tissue engineering. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46207.     

A comparative study of porous scaffolds with cubic and spherical macropores

Two kinds of polyester porous scaffolds having cubic and spherical macropores were fabricated, and a comparative study of their morphologies and mechanical properties were made in this paper. Poly(d,l-lactic-co-glycolic acid) (PLGA) scaffolds were prepared by room temperature compression molding and particulate leaching method based on cubic NaCl particles and paraffin spheres with a similar size range of 355-450 μm and a series of porosities (77-97%). Scanning electronic microscopy demonstrated that the spherical pore scaffolds exhibited better pore interconnectivity than the cubic pore ones. In compressive tests of both kinds of scaffolds, striking yield peaks were found at relatively low porosities, but just non-linear flexure behavior was observed at high porosities. The power-law relationships of compressive modulus and compressive strength versus porosity were confirmed in both foams. Comparison of the underlying scaling exponents reveals that the scaffolds with spherical pores are, at high porosities, with better compressive properties to a certain degree in contrast to those with cubic pores.     

Improvement of mechanical properties of macroporous β-tricalcium phosphate bioceramic scaffolds with uniform and interconnected pore structures

The biocompatible and degradable macroporous bioceramic scaffolds with high mechanical properties and interconnected porous structures play an important role in hard tissue regeneration and bone tissue engineering applications. In this study, the improvement of mechanical properties of macroporous β-tricalcium phosphate [β-Ca₃(PO₄)₂, β-TCP] bioceramic scaffolds with uniform macropore size and interconnected pores were fabricated by impregnation of the synthesized β-TCP nano-powder slurry into polymeric frames. The microstructures, mechanical properties and in vitro degradation of the fabricated samples were investigated. For a comparison, β-TCP scaffolds were also fabricated from commercial micro-size powders under the same conditions. The resultant scaffolds showed porosities ∼65% with uniform macropore size ranging from 400 to 550 μm and interconnected pore size ∼100 μm. The compressive strength of the samples fabricated from nano-size powders reached 10.87 MPa, which was almost twice as high as those fabricated from commercial micro-size powders, and was comparable to the high-end value (2–10 MPa) of human cancellous bone. Furthermore, the degradation of the β-TCP bioceramics fabricated from nano-size powders was apparently lower than those fabricated from commercial micro-size powders, suggesting the possible control of the degradation of the scaffolds by regulating initial powder size. Regarding the excellent mechanical properties and porous structures, the obtained macroporous β-TCP bioceramic scaffolds can be used in hard tissue regeneration and bone tissue engineering applications.     

Fabrication of bimodal porous PLGA scaffolds by supercritical CO2 foaming/particle leaching technique

Specific pore structure is a vital essential for scaffolds applied in tissue engineering. In this article, poly(lactide‐co‐glycolide) (PLGA) scaffolds with a bimodal pore structure including macropores and micropores to facilitate nutrient transfer and cell adhesion were fabricated by combining supercritical CO₂ (scCO₂) foaming with particle leaching technique. Three kinds of NaCl particles with different scales (i.e., 100–250, <75, <10 μm) were used as porogens, respectively. In particular, heterogeneous nucleation occurred to modify scCO₂ foaming/particle leaching process when NaCl submicron particles (<10 μm) were used as porogens. The observation of PLGA scaffolds gave a formation of micropores (pore size <10 μm) in the cellular walls of macropores (pore size around 100–300 μm) to present a bimodal pore structure. With different mass fractions of NaCl introduced, the porosity of PLGA scaffolds ranged from 68.4 ± 1.4 to 88.7 ± 0.4% for three NaCl porogens. The results of SEM, EDS, and in vitro cytotoxicity test of PLGA scaffolds showed that they had uniform structures and were compatible for cell proliferation with no toxicity. This novel scCO₂ foaming/particle leaching method was promising in tissue engineering due to its ability to fabricate scaffolds with precise pore structure and high porosity. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43644.     

Characterization and thermal degradation of poly(d,l‐lactide‐co‐glycolide) composites with nanofillers

Chemical and thermal characterization of poly(d ,l ‐lactide‐co‐glycolide) (PLGA) composites filled with hydroxyapatite (HA) or carbon nanotubes (CNT) were evaluated by infrared spectroscopy, differential scanning calorimetry, thermogravimetry, and dynamic–mechanical–thermal analysis. The morphology and distribution of the nanoparticles were studied by transmission electron microscopy. The composites were prepared by solvent casting using 30% HA or 1, 3, and 5% of pristine and functionalized CNT as nanoparticles and PLGA 75:25 and PLGA 50:50 as copolymer matrix. The Coats–Redfern and E₂ function methodologies were used to calculate the reaction order and the activation energy (E_a) of the thermal degradation process. It was found that the addition of nanoparticles increased the glass transition temperature (T_g) of the composites. Also, higher degradation temperatures and E_a values were obtained for PLGA–HA composites and compared with the neat copolymer, and the opposite behavior was exhibited by PLGA–CNT composites. The thermal and mechanical properties were highly dependent on the morphology and dispersion of the filler. The functionalization process of CNT promoted, to some extent, a better distribution and dispersion of CNT into the matrix, and these composites exhibited a slight enhancement on storage modulus. On the other hand, PLGA–HA composites showed a good dispersion but no improvement on the storage modulus below T_g. POLYM. ENG. SCI., 2013. © 2012 Society of Plastics Engineers     

Physical and mechanical properties of the fully interconnected chitosan ice‐templated scaffolds

Porous chitosan scaffolds were prepared with a freeze‐casting technique with different concentrations, 1.5 and 3 wt %, and also different cooling rates, 1 and 4°C/min. The pore morphology, porosity, pore size, mechanical properties, and water absorption characteristics of the scaffolds were studied. Scanning electron microscopy images showed that the freeze‐cast scaffolds were fully interconnected because of the existence of pores on the chitosan walls in addition to many unidirectionally elongated pores. Increases in the chitosan concentration and freezing rate led to elevations in the thickness of the chitosan walls and reductions in the pores size, respectively. These two results led to the enhancement of the compressive strength from 34 to 110 kPa for the scaffolds that had 96–98% porosity. Also, augmentation of the chitosan concentration and decreases in the freezing rate led to the reduction of the number of pores on the chitosan walls. Furthermore, the volume of water absorption increased with a reduction in the chitosan concentration and cooling rate from 690 to 1020%. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41476.     

Salmon calcitonin‐loaded PLGA microspheres/calcium phosphate cement composites for osteoblast proliferation

To improve the efficacy of salmon calcitonin (SCT) on disuse osteoporosis‐induced bone fracture, the sustained‐release vehicles delivered to bone fractures should be developed. In this study, SCT‐loaded poly(d ,l ‐lactic‐co‐glycolic acid) microspheres (SCT‐PLGA MS) with 20 kDa‐COOH and 40 kDa‐COOH (SCT‐PLGA‐20 COOH MS and SCT‐PLGA‐40 COOH MS) are incorporated into calcium phosphate cement (CPC) at various mass ratios. The cumulative release and mechanical properties of SCT‐PLGA MS/CPC composites decrease as PLGA MS/CPC mass ratio increase. Scanning electron microscopy images and the mass loss of composites indicate the MS from 20% SCT‐PLGA MS/CPC composites have mostly degraded after 8 weeks. In addition, SCT released from the 20% SCT‐PLGA‐20 MS/CPC composites significantly facilitate proliferation and differentiation of MC3T3‐E1 cells. In conclusion, 20% SCT‐PLGA‐20 COOH MS/CPC composites exhibit the sustained drug release, proper CPC degradation, good mechanical properties, and preferable osteoblast proliferation, which would be beneficial to their in vivo applications. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45486.     

Preparation and characterization of aliphatic polyurethane and hydroxyapatite composite scaffold

Novel porous composite scaffolds for tissue engineering were prepared from aliphatic biodegradable polyurethane (PU) elastomer and hydroxyapatite (HA). It was found that the aliphatic PU was possible to load up to 50 wt % HA. The morphology and properties of the scaffolds were characterized by scanning electron microscope, X‐ray diffraction, infrared absorption spectra, mechanical testing, dynamic mechanical analysis, and in vitro degradation measurement. The results indicated that the HA/PU scaffolds had an interconnected porous structure with a pore size mainly ranging from 300 to 900 μm, and 50–200 μm micropores existed on the pores' walls. The average pore size of macropores and micropores are 510 and 100 μm, respectively. The compressive strength of the composite scaffolds showed higher enhancement with increasing HA content. In addition, the polymer matrix was completely composed of aliphatic component and exhibited progressive mass loss in vitro degradation, and the degradation rate depended on the HA content in PU matrix. The porous HA/PU composite may have a good prospect to be used as scaffold for tissue engineering. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Preparation and in vitro degradation of novel bioactive polylactide/wollastonite scaffolds

Composite scaffolds for applications in bone engineering from poly(D,L ‐lactide) (PDLLA) incorporated with different proportional bioactive wollastonite powders were prepared through a salt‐leaching method, using NH₄HCO₃ as porogen. The pore structures and morphology of the scaffolds were determined by scanning electron microscopy (SEM). The bioactivity of composite materials was evaluated by examining its ability to initiate the formation of hydroxyapatite (Ca₁₀(PO₄)₆(OH)₂)(HAp) on its surface when immersed in simulated body fluids (SBF). The in vitro degradation behaviors of these scaffolds were systematically monitored at varying time periods of 1, 2, 4, 6, 8, 11, 14, 17, 20, 24, and 28 weeks postimmersion in SBF at 37°C. FT‐IR, XPS, XRD, and SEM measurements revealed that hydroxyapatite commenced to form on the surface of the scaffolds after 7 days of immersion in SBF. The measurements of weight loss, pH, and molecular weight of the samples indicated that PDLLA/wollastonite composite scaffolds degraded slower than the pure PDLLA scaffolds do. Addition of wollastonite enhanced the mechanical property of the composite scaffolds. The in vitro osteoblast culture experiment confirmed the biocompatibility of the scaffold for the growth of osteo‐blasts. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009.     

Fabrication and characterization of electrospun fibrous nanocomposite scaffolds based on poly(lactide‐co‐glycolide)/poly(vinyl alcohol) blends

Tissue engineering involves the fabrication of three‐dimensional scaffolds to support cellular in‐growth and proliferation. Ideally, the scaffolds should be similar to the native extracellular matrix (ECM). Electrospun polymer nanofibrous scaffolds are appropriate candidates for ECM mimetic materials since they mimic the nanoscale properties of ECM. Electrospun polymer nanocomposites based on poly(lactide‐co‐glycolide) (PLGA)/poly(vinyl alcohol) (PVA) and organically modified montmorillonite (OMMT) were prepared by a solution intercalation technique followed by electrospinning. The morphology of fibrous scaffolds based on these nanocomposites was investigated using scanning electron microscopy. The scaffolds showed highly porous structure within the nanofibres of diameters ranging from 400 to 700 nm. X‐ray diffractometry gave evidence of good dispersion of the OMMT in the blends with exfoliated morphology. Measurements of the water uptake and water contact angle of the fibrous scaffolds indicated significant improvement in the hydrophilicity of the scaffolds. Evaluations of the mechanical properties and unrestricted somatic stem cell culture of the electrospun fibrous nanocomposite scaffolds revealed that the PLGA90/PVA10/1.5% OMMT and PLGA90/PVA10/3% OMMT samples are the most useful from the tissue engineering application viewpoint. Copyright © 2010 Society of Chemical Industry     

Degradable and bioactive scaffold of calcium phosphate and calcium sulphate from self-setting cement for bone regeneration

Calcium sulphate/phosphate cement (CSPC) porous scaffolds were fabricated by introduction of calcium sulphate (CS) into calcium phosphate cement utilizing particle-leaching method. The morphology, porosity and mechanical strength as well as degradation of the CSPC scaffolds were characterized. The results reveal that the CSPC with 40 wt% CS content (40 CSPC) scaffolds with a porosity of 81% showed open macropores with the pore size of 200–500 μm. In addition, the 40 CSPC scaffolds with good degree of interconnected macropores degraded 60 wt% in Tris–HCl solution after 12 weeks. The proliferation, differentiation and morphology of MG₆₃ cells on the 40 CSPC scaffolds were determined using MTT assay, ALP activity and SEM. The results suggest that the CSPC scaffolds could stimulate cell proliferation and differentiation, indicating that CSPC scaffolds were biocompatible and had no negative effects on the cells in vitro. The CSPC scaffolds were implanted in femur bone defect of rabbits, and the in vivo biocompatibility and osteogenicity of the scaffolds were investigated. The results indicate that CSPC scaffolds exhibited good biocompatibility, degradability and osteogenesis in vivo.     

Evaluation of polycaprolactone − poly‐D,L‐lactide copolymer as biomaterial for breast tissue engineering

The potential of the copolymer polycaprolactone‐co‐ poly‐d ,l ‐lactic acid (PCLLA ) as a biomaterial for scaffold‐based therapy for breast tissue engineering applications was assessed. First, the synthesized PCLLA was evaluated for its processability by means of additive manufacturing (AM ). We found that the synthesized PCLLA could be fabricated into scaffolds with an overall gross morphology and porosity similar to that of polycaprolactone. The PCLLA scaffolds possessed a compressive Young's modulus (ca 46 kPa ) similar to that of native breast (0.5 ? 25 kPa ), but lacked thermal stability and underwent thermal degradation during the fabrication process. The PCLLA scaffolds underwent rapid degradation in vitro which was characterized by loss of the scaffolds' mechanical integrity and a drastic decrease in mass‐average molar mass (M _w) and number‐average molar mass (M _n) after 4 weeks of immersion in phosphate buffer solution maintained at 37 °C. The tin‐catalysed PCLLA scaffold was also found to have cytotoxic effects on cells. Although the initial mechanical properties of the PCLLA scaffolds generally showed potential for applications in breast tissue regeneration, the thermal stability of the copolymer for AM processes, biocompatibility towards cells and degradation rate is not satisfactory at this stage. Therefore, we conclude that research efforts should be geared towards fine‐tuning the copolymer synthesizing methods. © 2016 Society of Chemical Industry     

A parametric study on the processing parameters and properties of a porous poly(DL‐lactide‐co‐glycolide) acid 85/15 bioscaffolds

This study presents a comprehensive parametric study on the effects of processing parameters on the poly(DL‐lactide‐co‐glycolide) acid (PLGA) 85/15 scaffold's physical properties. Porous PLGA 85/15 scaffolds were prepared using a gas foaming/salt leaching technique. The processing parameters under examination for the gas foaming/salt leaching method included: gas saturation pressure (SP), gas saturation time, and NaCl/polymer mass ratio (NaCl/PMR). The physical properties considered in this study were the scaffold density, the scaffold porosity, and the average pore size of the scaffold. Young's moduli in compression, as well as the pore density (PD) inside the scaffold, were also studied. The results demonstrated optimum correlations of processing parameters are required to produce a scaffold with a high level of interconnectivity. In general, all scaffolds yielded by this experiment exhibited a porosity more than 90%, a relative density ranging from 0.0534 to 0.149 g/cm³, a PD ranging from 1.51 × 10⁶ to 6.72 × 10⁶ pores/cm³, and a compressive modulus ranging from 0.07 to 0.84 MPa. It was determined that the NaCl/PMR was the parameter that had the most significant effect on the physical properties of the scaffold. The average pore size was affected slightly by the SP only, and it was observed that the pore size was equivalent to the size of the NaCl particles used to make the scaffold. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers     

Additive Manufacturing of Poly(3-hydroxybutyrate-co-3-hydroxyvalerate)/Poly(D,L-lactide-co-glycolide) Biphasic Scaffolds for Bone Tissue Regeneration

Polyhydroxyalkanoates are biopolyesters whose biocompatibility, biodegradability, environmental sustainability, processing versatility, and mechanical properties make them unique scaffolding polymer candidates for tissue engineering. The development of innovative biomaterials suitable for advanced Additive Manufacturing (AM) offers new opportunities for the fabrication of customizable tissue engineering scaffolds. In particular, the blending of polymers represents a useful strategy to develop AM scaffolding materials tailored to bone tissue engineering. In this study, scaffolds from polymeric blends consisting of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) and poly(D,L-lactide-co-glycolide) (PLGA) were fabricated employing a solution-extrusion AM technique, referred to as Computer-Aided Wet-Spinning (CAWS). The scaffold fibers were constituted by a biphasic system composed of a continuous PHBV matrix and a dispersed PLGA phase which established a microfibrillar morphology. The influence of the blend composition on the scaffold morphological, physicochemical, and biological properties was demonstrated by means of different characterization techniques. In particular, increasing the content of PLGA in the starting solution resulted in an increase in the pore size, the wettability, and the thermal stability of the scaffolds. Overall, in vitro biological experiments indicated the suitability of the scaffolds to support murine preosteoblast cell colonization and differentiation towards an osteoblastic phenotype, highlighting higher proliferation for scaffolds richer in PLGA.