Solvent Casting Particulate Leaching Research Articles

A NOVEL ANTI-PROLIFERATIVE ACTIVITY (EC50) OF PEGAGA (Centella asiatica) EXTRACT THROUGH IN VITRO 3-D CULTURE MICROENVIRONMENT

Centella asiatica or pegaga is one of the botanical plants that consists of many phytochemicals and is known for being able to offer various effects on wound healing, as well as functioning as an antioxidant and anticancer property. Therefore, this study was carried out to determine the efficacy of Centella asiatica water and alcohol-based extracts on the anti-proliferative activity of human lung cancer cells (A549) and normal fibroblast (IMR90) by mean of in vitro 3-D cell culture system. A porous 3-D scaffold was fabricated from poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV) using solvent-casting particulate-leaching (SCPL) process. Antioxidant analysis (total phenolic content (TPC), DPPH and FRAP assays) was conducted prior to the 3-D cell culture study. The results showed that the extract contained 7.50 ± 1.10 mg/ml of asiaticoside and 0.74 ± 0.24 mg/ml of madecassoside. These bio-active compounds were believed to inhibit the proliferation of cancer cells (A549). The availability of phenolic compounds in the extract (TPC: 10133 ± 119.30 mg/100 g) had proven that the antioxidant properties existed. Moreover, the other values obtained from the antioxidant analysis revealed its capacity as a good source of antioxidant (DPPH: 87 ± 1.0%; FRAP: 127 ± 14.98 mg/100 g). Next, the lung cancer cells (A549) were cultured using a two-dimensional (2-D) system to generate the IC50 value of 5.75 ± 1.0 µg/ml. The A549 cell viability (MTS assay) after a 3-day incubation exhibited a good sign of mortality for the both treated models ranging from 55% to 70% as compared to control one (without treatment) (p>0.05). However, when the extract was exposed to a normal fibroblast IMR90, the cell growth of the both treated models exhibited an almost 2-fold greater cell numbers than that of the untreated models (p<0.05) indicating that the extract did not possess any possible threat to a normal and healthy cell. Therefore, the use of Centella asiatica extracts in terminating cancer cells has been proven to be able to inhibit cell growth (greater than 40%) in just 3 days of incubation.

Efficacy Study of Carrageenan as an Alternative Infused Material (Filler) in Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) Porous 3D Scaffold

Polymeric porous 3D scaffold plays an important role in culturing mammalian cells asex vivomodel. However, the scaffold used is ineffective due to its structural and cell acceptability weaknesses. Therefore, this research attempts to overcome the weaknesses by using carrageenan from red seaweedKappaphycus alvareziias an alternative infused material (filler) of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) porous 3D scaffold. The 3D scaffold was conventionally fabricated using the solvent-casting particulate-leaching (SCPL) method. Carrageenan was later infused into 3D porous scaffolds under vacuum pressure and freeze-drying process. Five carrageenan concentrations were prepared and its physicochemical properties such as pH and viscosity were carried out on each concentration to determine the best solutions to produce a new composite 3D structure. The preliminary result shows that carrageenan concentrations of 2, 4, and 6% (w/v) were considered the best solutions for the infusion process due to its stable rheology properties. The pH and viscosity profiles of three selected carrageenan solutions were exhibited in the range of 9.00–9.20 and 0.047–1.144 Pa·s, respectively. Moreover, the incorporated carrageenan gel fraction was in the range of 4.30% to 14.95% (w/w) which was determined by gravimetric analysis and dye staining method (visual assessment). The well-infused carrageenan 3D scaffold was further characterized based on its internal morphology and degradability study. The vertical cross-sections of the scaffolds revealed homogeneous accumulation of dried gelatinous carrageenan which was covered throughout its pores wall. The degradation rate (K) of the carrageenan infused 3D scaffold was between0.01±1.66(mg/day) and0.03±3.23(mg/day). The higher the carrageenan concentration used, the faster the degradation rate occurring (p<0.05). The 3D infused scaffold of 4% (w/v) carrageenan concentration (S2) produced a moderate degradation rate of0.02±1.55(mg/day) with a sustained structural integrity up to 28 days. The carrageenan infused scaffold of 4% (w/v) was demonstrated to be the best 3D structure for a long-term cell culture (>2 weeks). In conclusion, the usage of carrageenan as a composite material exhibits its great potential to be used in tissue engineering application and 3D cell culture model.

Poly(butylene adipate-co-terephthalate) scaffolds: processing, structural characteristics and cellular responses

ABSTRACTThe aliphatic-aromatic copolyester, poly(butylene adipate-co-terephthalate) (PBAT) combines good mechanical and thermal properties with biodegradation ability. However, until now, researches in its potential medical use remain limited. Only in a few studies blends of PBAT with routinely used biocompatible polymers had been prepared and investigated regarding tissue engineering applications. Therefore, in this study, we decided to determine processability of neat PBAT as a scaffold material for bone tissue by using different fabrication methods i.e. solvent evaporation, electrospinning, solvent casting-particulate leaching (SCPL) and melt molding-particulate leaching. The results of physicochemical characterizations and cell culture studies with MC3T3-E1 preosteoblasts confirmed that neat PBAT has favorable characteristics for bone tissue engineering, however, fabrication method strongly affects the cellular responses. Regarding to the characterizations and cell cultures, PBAT scaffolds produced by SCPL and electrospinning are proposed to be used for bone tissue engineering.

Fabrication of a Bioactive, PCL-based "Self-fitting" Shape Memory Polymer Scaffold.

Tissue engineering has been explored as an alternative strategy for the treatment of critical-sized cranio-maxillofacial (CMF) bone defects. Essential to the success of this approach is a scaffold that is able to conformally fit within an irregular defect while also having the requisite biodegradability, pore interconnectivity and bioactivity. By nature of their shape recovery and fixity properties, shape memory polymer (SMP) scaffolds could achieve defect "self-fitting." In this way, following exposure to warm saline (~60 ºC), the SMP scaffold would become malleable, permitting it to be hand-pressed into an irregular defect. Subsequent cooling (~37 ºC) would return the scaffold to its relatively rigid state within the defect. To meet these requirements, this protocol describes the preparation of SMP scaffolds prepared via the photochemical cure of biodegradable polycaprolactone diacrylate (PCL-DA) using a solvent-casting particulate-leaching (SCPL) method. A fused salt template is utilized to achieve pore interconnectivity. To realize bioactivity, a polydopamine coating is applied to the surface of the scaffold pore walls. Characterization of self-fitting and shape memory behaviors, pore interconnectivity and in vitro bioactivity are also described.

Fabrication of a Bioactive, PCL-based "Self-fitting" Shape Memory Polymer Scaffold

Tissue engineering has been explored as an alternative strategy for the treatment of critical-sized cranio-maxillofacial (CMF) bone defects. Essential to the success of this approach is a scaffold that is able to conformally fit within an irregular defect while also having the requisite biodegradability, pore interconnectivity and bioactivity. By nature of their shape recovery and fixity properties, shape memory polymer (SMP) scaffolds could achieve defect “self-fitting.” In this way, following exposure to warm saline (~60 ºC), the SMP scaffold would become malleable, permitting it to be hand-pressed into an irregular defect. Subsequent cooling (~37 ºC) would return the scaffold to its relatively rigid state within the defect. To meet these requirements, this protocol describes the preparation of SMP scaffolds prepared via the photochemical cure of biodegradable polycaprolactone diacrylate (PCL-DA) using a solvent-casting particulate-leaching (SCPL) method. A fused salt template is utilized to achieve pore interconnectivity. To realize bioactivity, a polydopamine coating is applied to the surface of the scaffold pore walls. Characterization of self-fitting and shape memory behaviors, pore interconnectivity and in vitro bioactivity are also described.

Effect of processing techniques on the 3D microstructure of poly (l‐lactic acid) scaffolds reinforced with wool keratin from different sources

ABSTRACTThe aim of this work was the analysis of morphologies of poly (l‐lactic acid)/keratin tridimensional scaffolds developed by using two main solvent based techniques: solvent casting particulate leaching in the presence of paraffin microspheres as porogen, and thermally induced phase‐separation process. Keratins from different sources were used. Specifically, keratin from Merino wool (KM) and Brown Alpaca (KA) were dispersed in dioxane or 1,4‐dioxane/water mixture and then the keratin structure after interaction with 1.4‐dioxane was investigated by means of electrophoresis and spectroscopic analysis. A detailed morphological characterization of the scaffold systems obtained by the two different methods was performed by using field emission scanning electron microscopy. The effect of porogen content, solvent composition and processing parameters, such as the influence of keratin presence (1 wt %) and source (KA and KM) were evaluated. The results reveal that 1,4‐dioxane, used as based solvent in the two selected processes, does not negatively affect the keratin structure. A slight change in the procedure parameters, such as porogen content or solvent/non‐solvent ratio, significantly affects the resulting porosity and architecture of the obtained PLLA and PLLA/keratin scaffolds. Both keratins can be considered as suitable fillers able to modify the pore architecture and interconnection of three‐dimensional PLLA/keratin porous composites obtained by the two different solvent assisted techniques. Of note, both composites are biocompatible, as demonstrated by the culture adult bone‐marrow mesenchymal stem cells without signs of toxicity. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42890.

English

Polyhydroxyalkanoates (PHAs) has been investigated for more than eighty years. Ever since then, the scientists are kept on synthesizing and developing new polymers and application to suit human interests nowadays. The resourcefulness of PHAs has made them a good candidates for the study of their potential in a variety of areas from biomedical/medical fields to food, packaging, textile and household material. In medical field (specifically in tissue engineering application), producing a biocompatible 3-D scaffold with adaptable physical properties are essential. However, to the best of our knowledge, scaffolds from PHB and PHBV with thickness greater than 1 mm have not been produced yet. In this work, PHB and PHBV porous 3-D scaffolds with an improved thickness greater than 4 mm was fabricated using conventional method of solvent-casting particulate-leaching (SCPL). A preliminary assessment on the improved thickness 3-D scaffolds was carried out to examine its pore interconnectivity by using non-invasive color staining method. The vertical cross sections image of the stained scaffolds was analyzed by image analyzer software. This technique was considered simple, fast and cost effective method prior to the usage of super accurate analytical instruments (micro-computed tomography). The results showed that over 80% of the pores have been interconnected with the adjacent pores. Moreover, there was a good correlation between the predicted pore interconnectivity and porosity. These results indicated how well a simple technique can do by giving an overview of the internal morphology of a porous 3-D structure material.

DEVELOPMENT OF A RAPID CONTINUOUS FLOW SALT LEACHING KIT FOR FABRICATION OF POLY(3-HYDROXYBUTYRIC ACID-CO-3-HYDROXYVALERATE) (PHBV) POROUS 3-D SCAFFOLD

Polyhydroxyalkanoates (PHAs) that are synthesized from bacteria that are predominantly produced by microbial fermentation processes on organic waste, such as palm oil mill effluent (POME), olive oil and kitchen waste, contribute to a sustainable waste management. A great variety of materials from this family can be produced, however the application of PHAs in the production of scaffolds in tissue engineering has been mainly constrained to poly(hydroxybutyrate-co-valerate) (PHBV) due to its highly adjustable physico-chemical properties. One of the common methods in making the 3-D scaffolds is by performing solvent-casting particulate-leaching (SCPL) process, but this process requires a long period of soaking in water to extract the entire salt particle in the 3-D scaffolds. Therefore, the objective of this study is to develop a new method to the conventional method of salt leaching process via a highly efficient continuous flow leaching kit. The salt leaching process was carried out by (1) immersing the 3-D porous scaffolds in a fabricated static container containing tap water and (2) by allowing a pre-setting continuous flow rate of water. The concentration of sodium chloride (NaCl) was calculated periodically for both processes based on the salt standard calibration curve. The results showed that the exhaustive salt leaching of the conventional process occurred at 48 ± 5 hrs with the needs of changing the water twice a day. In contrast, the exhaustive salt leaching process via continuous flow leaching kit occurred at 40 ± 5 mins, 72 times faster than the conventional method (p<0.05). Therefore, the salt leaching process using continuous flow leaching kit can be considered a highly efficient and time saving procedure as compared to the conventional method.

Effect of Different Solvents in Solvent Casting of Porous caffolds – In Biomedical and Tissue Engineering Applications

In the present investigation, PLA porous scaffolds was fabricated using NaCl as porogen in three different solvents i.e. 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP), dichloromethane (DCM) and chloroform (CF) respectively, by solvent casting particulate leaching method. The morphology, structure and thermal behaviour of the PLA scaffolds for porosity measurement were evaluated using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR); thermo gravimetric analysis (TGA) and differential scanning calorimetry (DSC). The developed porous scaffolds were further characterized for porosity measurement, solvent uptake property and water absorption capacity at different temperatures. PLA/ CF scaffold depicted higher porosity factor (93%) along with enhanced water uptake capacity (220%) as against PLA/ HFIP scaffold (75%). However PLA/ DCM scaffolds illustrated more thermal stability as compared with PLA/ HFIP and PLA/ CF scaffolds.

Effect of the preparation methods on architecture, crystallinity, hydrolytic degradation, bioactivity, and biocompatibility of PCL/bioglass composite scaffolds.

In this study, two different composition gel derived silica-rich (S2) or calcium-rich (A2) bioactive glasses (SBG) from a basic CaO-P2 O5 -SiO2 system were incorporated into poly(ε-caprolactone) (PCL) matrix to obtain novel bioactive composite scaffolds for bone tissue engineering applications. The composites were fabricated in the form of highly porous 3D scaffolds using following preparation methods: solvent casting particulate leaching (SCPL), solid-liquid phase separation, phase inversion (PI). Scaffolds containing 21% vol. of each bioactive glass were characterized for architecture, crystallinity, hydrolytic degradation, surface bioactivity, and cellular response. Results indicated that the use of different preparation methods leads to obtain highly porous (60-90%) materials with differentiated morphology: pore shape, size, and distributions. Thermal analysis (DSC) showed that the preparation method of materials and addition of bioactive glass particles into polymer matrix induced the changes of PCL crystallinity. Composites obtained by SCPL and PI method containing A2 SBG rapidly formed a hydroxyapatite calcium phosphate surface layer after incubation in SBF. Bioactive glasses used as filler in composite scaffolds could neutralize the released acidic by-products of the polymer degradation. Preliminary in vitro biological studies of the composites in contact with osteoblastic cells showed good biocompatibility of the obtained materials. Addition of bioactive glass into the PCL matrix promotes mineralization estimated on the basis of the ALP activity. These results suggest that through a process of selection appropriate methods of preparation and bioglass composition it is possible to design and obtain porous materials with suitable properties for regeneration of bone tissue.

Fabrication and Properties of Porous Scaffolds of PLA-PEG Biocomposite for Bone Tissue Engineering

Porous scaffolds of polylactic acid-polyethylene glycol block copolymers (PLA-PEG) biocomposite were fabricated by solvent casting-particulate leaching method using sodium chloride as the porogen. With the aim of evaluating the influence of porosity on mechanical properties and biocompatibility, three specimens of scaffolds which have different porosity (around 50%, 60%, 70%) were fabricated. Murine fibroblast grew cells (L929) were seeded into PLA-PEG porous biocomposite scaffolds. The tetrazolium salt 3-[4, 5-dimethylthiazol-2-yl]-2, 5-diphenyltetrazolium Bromide (MTT), scanning electron microscopy and confocal microscopy were carried out to characterize cell proliferation and morphology. The composite scaffolds with the porosity of 50% possessed better mechanical properties. All scaffolds support attachment, spreading and proliferation of L929, and the biocompatibility of scaffolds could be improved by increasing the porosity. The fabricated PLA-PEG porous biocomposite scaffolds with good mechanical properties and biocompatibility might be used in bone tissue engineering.

Inorganic–Organic Shape Memory Polymer (SMP) Foams with Highly Tunable Properties

Thermoresponsive shape memory polymers (SMPs) are a class of smart materials that can return from a temporary to a permanent shape with the application of heat. Porous SMP foams exhibit unique properties versus solid, nonporous SMPs, enabling their utility in different applications, including some in the biomedical field. Reports on SMP foams have focused on those based on organic polymer systems. In this study, we have prepared inorganic-organic SMP foams comprising inorganic polydimethylsiloxane (PDMS) segments and organic poly(ε-caprolactone) PCL segments. The PCL segments served as switching segments to induce shape changing behavior whereas the length of the PDMS soft segment was systematically tuned. SMP foams were formed via the photochemical cure of acrylated (AcO) macromers AcO-PCL(40)-block-PDMS(m)-block-PCL(40)-OAc (m = 0, 20, 37, 66 and 130) using a revised solvent casting/particulate leaching (SCPL) method. By varying the PDMS segment length, PDMS-PCL foams having excellent shape memory behavior were obtained that exhibited highly tunable properties, including pore size, % porosity, compressive modulus, and degradation rate.

Porous inorganic–organic shape memory polymers

Thermoresponsive shape memory polymers (SMPs) are a type of stimuli-sensitive materials that switch from a temporary shape back to their permanent shape upon exposure to heat. While the majority of SMPs have been fabricated in the solid form, porous SMP foams exhibit distinct properties and are better suited for certain applications, including some in the biomedical field. Like solid SMPs, SMP foams have been restricted to a limited group of organic polymer systems. In this study, we prepared inorganic–organic SMP foams based on the photochemical cure of a macromer comprised of inorganic polydimethylsiloxane (PDMS) segments and organic poly(ε-caprolactone) (PCL) segments, diacrylated PCL40-block-PDMS37-block-PCL40. To achieve tunable pore size with high interconnectivity, the SMP foams were prepared via a refined solvent-casting/particulate-leaching (SCPL) method. By varying design parameters such as degree of salt fusion, macromer concentration in the solvent and salt particle size, the SMP foams with excellent shape memory behavior and tunable pore size, pore morphology, and modulus were obtained.

Fabrication and properties of porous scaffold of zein/PCL biocomposite for bone tissue engineering

The aim of this study was to fabricate porous scaffolds of zein/poly(ε-caprolactone) (PCL) biocomposite by solvent casting–particulate leaching method using sodium chloride particles as the porogen. Porous biocomposite scaffolds with porosity around 70% and well-interconnected network were obtained. The incorporation of zein into PCL led to the improvement of hydrophilicity as indicated by the results of water contact angle measurement. After immersion in phosphate buffered saline (PBS) in vitro for 28days, it was observed that the degradation rate of the zein/PCL biocomposite scaffold was faster than the PCL scaffold and that the rate could be tailored by adjusting the amount of zein in the composite. The results demonstrate the potential of the zein/PCL biocomposite scaffolds to be used in tissue engineering strategies to regenerate bone defects.

Plasma processing of scaffolds: perspectives for Tissue Engineering

Since the mid-1980s, Tissue Engineering has been proposed as a potential tool in addressing the repair, replacement, and/or regeneration of vital organs. Thus this field is now an interesting alternative to artificial prosthesis and confronts the transplantation crisis, i.e., the shortage of donor tissues and organs available for transplantation 1 . This new emerging field is based on the use of cells (particularly stem cells) seeded in a threedimensional (3D) scaffold (most often made og a biodegradable polymer), that provides the initial structural integrity and organizational backbone for cells to assemble into a functional tissue 2 . Thus, scaffolds, characterized by high porosity, proper pore size, shape, surface area, suitable biodegradability and biocompatibility, stiffness and mechanical integrity, are required. These 3D structures have to allow the necessary support for cell attachment, proliferation, differentiation, leading to a correct tissue regeneration in advanced applications. Nowadays, several fabrication techniques have been employed to realize scaffolds with suitable biocompatibility 3-5 . For instance, Solvent Casting/Particulate Leaching (SC/PL) is the most easy, low time-consuming and cheap conventional scaffolding technique, used by material engineers. It allows the control of micro-structural characteristics such as total porosity and total pore size 6 . Another known conventional technique includes the supercritical carbon dioxide (scCO2) as porogen, that is advantageous because it does not require organic solvents and leaching process to eliminate the porogen 7 . Also, with this technique it is possible to control the total porosity and pore size, even if the pores are randomly distributed inside the scaffold. Unlike conventional machining, computer-aided technologies, like Solid Free-Form fabrication (SFF) and Rapid Prototyping (RP), are able to build scaffolds by selectively adding materials, layer-by-layer, as specified by a computer program, creating a highly reproducible architecture along the 3D construct 8 . Surface properties influence cell-material interactions in the tissue engineered structures. Generally, when cells are seeded in vitro into 3D scaffolds, cell adhesion is favoured at the peripheries of the constructs, resulting in poorly populated inner parts, because the external surfaces of the scaffolds are more accessible than the inner ones. Thus, by controlling scaffold surface chemistry by some surface modification techniques, it should be possible to control adsorption of proteins from the cell culture medium and, in turn, to enhance cell 13th International Conference on Plasma Surface Engineering, September 10-14, 2012, in Garmisch-Partenkirchen, Germany

Comparison of Short-Run Cell Seeding Methods for Poly(L-Lactide-co-1,5-Dioxepan-2-one) Scaffold Intended for Bone Tissue Engineering

Constructs intended for bone tissue engineering are influenced by the initial cell seeding procedure. The seeding method should be rapid, convenient, improve cell spatial distribution, and have no negative effects on cellular viability and differentiation. This study aimed to compare the effect of short-run seeding methods (centrifuge and vortex) with a static method on the scaffolds prepared from poly(L-lactide-co-1,5-dioxepan-2-one) by solvent-casting particulate-leaching (SCPL) technique. Human osteoblast-like cells (HOB) were seeded by the three methods described above. The seeding efficiency was determined by attached cell numbers. Cellular proliferation was analyzed by WST-1 and dsDNA assay. Cell distribution was examined by scanning electron (SEM) and fluorescence microscopy. Expression of alkaline phosphatase (ALP), collagen type I (Col I), osteocalcin (OC) and proliferating cell nuclear antigen (PCNA) were determined by real time RT-PCR. Results indicated that centrifuge and vortex increased seeding efficiency and had no negative effects on cellular viability. The data obtained by the fluorescence microscope confirmed the SEM results that the vortex method improved cell distribution through the scaffolds more than the other two methods (p<0.05). The RT-PCR results showed no significant differences on the expression of mRNA between the three methods of the above markers. The vortex method was found to be a simple and feasible seeding method for the poly(L-lactide-co-1,5-dioxepan-2-one) scaffolds.

Fabrication of poly(lactic acid) scaffolds by a modified solvent casting/porogen leaching method

AbstractA modified solvent casting/particulate leaching (SC/PL) method was developed to fabricate thick three-dimensional poly(lactic acid) (PLA) scaffolds with controlled pore size and porosity, and much shorter processing time. The pasty mixture of PLA/CHCl3/NaCl was sealed in a Buchner funnel by a piston with a suction flask connected. A vacuum pump was used to facilitate the volatilization of solvent. The scaffolds were obtained by subsequent removal of NaCl in deionized water. The pore size within the scaffold was in good accordance with the particle size of NaCl (&lt; 210, 210~310, 310~420 and 420~500 μm), all of which had more than 89 % of porosity, 1.95 ± 0.2 MPa of compressive modulus and non-cytotoxic to L929 cells. To demonstrate the applicability of the SC/VV/PL method, thick cylindrical and tubular porous scaffolds have been produced in this study. Compared with the traditional SC/PL without vacuum volatilization, the modified method, namely, solvent casting/vacuum volatilization/particulate leaching (SC/VV/PL) method, provide a more efficient way to fabricate thick scaffolds.

Polyurethane (PU) scaffolds prepared by solvent casting/particulate leaching (SCPL) combined with centrifugation

This article reports an enhanced solvent casting/particulate (salt) leaching (SCPL) method developed for preparing three-dimensional porous polyurethane (PU) scaffolds for cardiac tissue engineering. The solvent for the preparation of the PU scaffolds was a mixture of dimethylformamide (DFM) and tetrahydrofuran (THF). The enhanced method involved the combination of a conventional SCPL method and a step of centrifugation, with the centrifugation being employed to improve the pore uniformity and the pore interconnectivity of scaffolds. Highly porous three-dimensional scaffolds with a well interconnected porous structure could be achieved at the polymer solution concentration of up to 20% by air or vacuum drying to remove the solvent. When the salt particle sizes of 212–295, 295–425, or 425–531 µm and a 15% w/v polymer solution concentration were used, the porosity of the scaffolds was between 83–92% and the compression moduli of the scaffolds were between 13 kPa and 28 kPa. Type I collagen acidic solution was introduced into the pores of a PU scaffold to coat the collagen onto the pore walls throughout the whole PU scaffold. The human aortic endothelial cells (HAECs) cultured in the collagen-coated PU scaffold for 2 weeks were observed by scanning electron microscopy (SEM). It was shown that the enhanced SCPL method and the collagen coating resulted in a spatially uniform distribution of cells throughout the collagen-coated PU scaffold.

Preparation and characterization of bioactive mesoporous wollastonite – Polycaprolactone composite scaffold

A well-defined mesoporous structure of wollastonite with high specific surface area was synthesized using surfactant P123 (triblock copolymer) as template, and its composite scaffolds with poly(ɛ-caprolactone) (PCL) were fabricated by a simple method of solvent casting-particulate leaching. The measurements of the water contact angles suggest that the incorporation of either mesoporous wollastonite (m-WS) or conventional wollastonite (c-WS) into PCL could improve the hydrophilicity of the composites, and the former was more effective than the later. The bioactivity of the composite scaffold was evaluated by soaking the scaffolds in a simulated body fluid (SBF) and the results show that the m-WS/PCL composite (m-WPC) scaffolds can induce a dense and continuous layer of apatite after soaking for 1 week, as compared with the scattered and discrete apatite particles on the c-WS/PCL composite (c-WPC) scaffolds. The m-WPC had a significantly enhanced apatite-forming bioactivity compared with the c-WPC owing to the high specific surface area and pore volume of m-WS. In addition, attachment and proliferation of MG 63 cells on m-WPC scaffolds were significantly higher than that of c-WPC, revealing that m-WPC scaffolds had excellent biocompatibility. Such improved properties of m-WPC should be helpful for developing new biomaterials and may have potential use in hard tissue repair.

A mesoporous bioactive glass/polycaprolactone composite scaffold and its bioactivity behavior

Composite scaffolds of mesoporous bioactive glass (MBG)/polycaprolactone (PCL) and conventional bioactive glass (BG)/PCL were fabricated by a solvent casting-particulate leaching method, and the structure and properties of the composite scaffolds were characterized. The measurements of the water contact angles suggest that the incorporation of either MBG or BG into PCL can improve the hydrophilicity of the composites, and the former is more effective than the later. The bioactivity of the composite scaffold is evaluated by soaking the scaffolds in a simulated body fluid (SBF) and the results show that the MBG/PCL composite scaffolds can induce a dense and continuous layer of apatite after soaking in SBF for 3 weeks, as compared with the scattered and discrete apatite particles on the BG/PCL composite scaffolds. Such improvements (improvements of the hydrophilicity and apatite forming ability) should be helpful for the extensive applications of PCL scaffold in tissue engineering.