Preparation of adriamycin gelatin microsphere-loaded decellularized periosteum that is cytotoxic to human osteosarcoma cells

The purpose of this study was to develop a novel approach to treat bone osteosarcoma using a multipurpose scaffold aiming for local drug delivery. The slowly releasing microspheres was designed to deliver the chemotherapy drug adriamycin (ADM) and a decellularized (D) periosteum scaffold (which is known to be able to promote bone regeneration) was used to carry these microspheres. D-periosteum was obtained by physical and chemical decellularization. Histological results showed that the cellular components were effectively removed. The D-periosteum showed an excellent cytocompatibility and the ability to promote adhesion and growth of fibroblasts. Two kinds of slowly releasing microspheres, adriamycin gelatin microspheres (ADM-GMS) and adriamycin poly (dl-lactide-co-glycolide) gelatin microspheres (ADM-PLGA-GMS), were prepared and anchored to D-periosteum, resulting in two types of drug-releasing regenerative scaffolds. The effectiveness of these two scaffolds in killing human osteosarcoma cells was tested by evaluating cell viability overtime of the cancer cells cultured with the scaffolds. In summary, a gelatin/decellularized periosteum-based biologic scaffold material was designed aiming for local delivery of chemotherapy drugs for osteosarcoma, with the results showing ability of the scaffolds in sustaining release of the cancer drug and in suppressing growth of the cancer cells in vitro.     

Inter-connecting pores of chitosan scaffold with basic fibroblast growth factor modulate biological activity on human mesenchymal stem cells

In this study, we developed bio-active molecules immobilized chitosan scaffolds with controlled pore architectures for enhanced viability of human mesenchymal stem cells (hMSCs). The decreasing in molecular weight of chitosan by ultrasonication of chitosan solution was effective in the formation of porous chitosan scaffolds, resulting in an increase of inter-connecting micropores (∼10 μm) between macropores. Using a layer-by-layer method, we then prepared heparin-coated chitosan scaffolds as depots for basic fibroblast growth factors (bFGF). Enzyme-linked immunosorbent assays confirmed that heparin-coated chitosan scaffolds could bind higher amount of bFGF (24.21 ng/mg) compared to 2.53 ng/mg of non-coated scaffold. Moreover, we were able to manipulate the release profiles of bFGF from the scaffolds for 7 days. In vitro studies showed that chitosan scaffolds induced the improved viability and proliferation of hMSCs through their synergetic effects of the inter-connecting micropores and the sustained released of bFGF. Our results suggest that bFGF immobilized chitosan scaffolds with controlled inter-connecting pores, in combination with other heparin-binding growth factors, have potential implants for controlling biological functions in regenerative medicine.     

Increased matrix synthesis by fibroblasts with decreased proliferation on synthetic chitosan-gelatin porous structures

Influence of mechanical characteristics and matrix architecture of substrates used in cell culture is an important issue to tissue engineering. Chitosan‐based materials have been processed into porous structures, injectable gels and membranes, and are investigated to regenerate various tissues. However, the effect of these structures on cell growth and matrix production in accordance with each of the differing scaffolds has not been examined. We investigated the influence of porous structures, hydrogels, and membranes on the growth of normal human fibroblasts and their matrix production in a serum‐free system. We used chitosan alone and in combination with gelatin. Injectable hydrogels were prepared using 2‐glycerol phosphate. From the same solution, porous scaffolds and membranes were formed using controlled rate freezing and lyophilization, and air‐drying, respectively. Fibroblast growth was evaluated on the 4th and 10th days using flow cytometry and CFDA‐SE pre‐staining. Cell morphology was assessed using actin and nucleus staining. Total protein content, collagen, tropoelastin, and MMP2/MMP‐9 activity in the media supernatant were assessed by BCA, Sircol?, Fastin Elastin, and fluorogeneic peptide assays. Collagen accumulated in the matrix was assessed by Sircol? assay after pepsin/acetic acid digestion and by Masson's Trichrome staining. These results showed increased viability of fibroblasts on chitosan–gelatin porous scaffold with decreased proliferation relative to tissue culture plastic (TCP) surface despite the cells showing spindle shape. The total protein, collagen, and tropoelastin contents were higher in the spent media from chitosan–gelatin porous scaffolds compared to other conditions. MMP2/MMP9 activity was comparable to TCP. An increase in collagen content was also observed in the matrix, suggesting increased matrix deposition. In summary, matrix production is influenced by the form of chitosan structures, which significantly affects the regenerative process. Biotechnol. Bioeng. 2012; 109:1314–1325. © 2011 Wiley Periodicals, Inc.     

Human endothelial cell growth and phenotypic expression on three dimensional poly(lactide-co-glycolide) sintered microsphere scaffolds for bone tissue engineering

Bone tissue engineering offers promising alternatives to repair and restore tissues. Our laboratory has employed poly(lactide-co-glycolide) PLAGA microspheres to develop a three dimensional (3-D) porous bioresorbable scaffold with a biomimetic pore structure. Osseous healing and integration with the surrounding tissue depends in part on new blood vessel formation within the porous structure. Since endothelial cells play a key role in angiogenesis (formation of new blood vessels from pre-existing vasculature), the purpose of this study was to better understand human endothelial cell attachment, viability, growth, and phenotypic expression on sintered PLAGA microsphere scaffold. Scanning electron microscopy (SEM) examination showed cells attaching to the surface of microspheres and bridging the pores between the microspheres. Cell proliferation studies indicated that cell number increased during early stages and reached a plateau between days 10 and 14. Immunofluorescent staining for actin showed that cells were proliferating three dimensionally through the scaffolds while staining for PECAM-1 (platelet endothelial cell adhesion molecule) displayed typical localization at cell-cell contacts. Gene expression analysis showed that endothelial cells grown on PLAGA scaffolds maintained their normal characteristic phenotype. The cell proliferation and phenotypic expression were independent of scaffold pore architecture. These results demonstrate that PLAGA sintered microsphere scaffolds can support the growth and biological functions of human endothelial cells. The insights from this study should aid future studies aimed at enhancing angiogenesis in three dimensional tissue engineered scaffolds.     

Characterization of a new degradable polymer scaffold for regeneration of the dermis: In vitro and in vivo human studies

Full thickness skin wounds in humans heal with scars, but without regeneration of the dermis. A degradable poly(urethane urea) scaffold (PUUR), Artelon® is already used to reinforce soft tissues in orthopaedics, and for treatment of osteoarthritis of the hand, wrist and foot. In this paper we have done in vitro experiments followed by in vivo studies to find out whether the PUUR is biocompatible and usable as a template for dermal regeneration. Human dermal fibroblasts were cultured on discs of PUUR, with different macrostructures (fibrous and porous). They adhered to and migrated into the scaffolds, and produced collagen. The porous scaffold was judged more suitable for clinical applications and 4 mm Ø, 2 mm-thick discs of porous scaffold (12% w/w or 9% w/w polymer solution) were inserted intradermally in four healthy human volunteers. The implants were well tolerated and increasing ingrowth of fibroblasts was seen over time in all subjects. The fibroblasts stained immunohistochemically for procollagen and von Willebrand factor, indicating neocollagenesis and angiogenesis within the scaffolds. The PUUR scaffold may be a suitable material to use as a template for dermal regeneration.Key words: dermal regeneration, tissue engineering, polymer scaffold, wound healing, in vitro, in vivo, guided tissue regeneration, human, burns     

Incorporated-bFGF polycaprolactone/polyvinylidene fluoride nanocomposite scaffold promotes human induced pluripotent stem cells osteogenic differentiation

Bioactive scaffolds that can increase transplanted cell survival time at the defect site have a great promising potential to use clinically since tissue regeneration or secretions crucially depend on the transplanted cell survival. In this study embedded basic fibroblast growth factor (bFGF)-polycaprolactone-polyvinylidene fluoride (PCL-PVDF) hybrid was designed and fabricated by electrospinning as a bio-functional nanofibrous scaffold for bone tissue engineering. After morphological characterization of the PCL-PVDF (bFGF) scaffold, nanofibers biocompatibility was investigated by culturing of the human induced pluripotent stem cells (iPSCs). Then, the bone differentiation capacity of the iPSCs was evaluated when grown on the PCL-PVDF and PCL-PVDF (bFGF) scaffolds in comparison with culture plate as a control using evaluating of the common osteogenic markers. The viability assay displayed a significant increase in iPSCs survival rate when grown on the bFGF content scaffold. The highest alkaline phosphatase activity and mineralization were detected in the iPSCs while grown on the PCL-PVDF (bFGF) scaffolds. Obtained results from gene and protein expression were also demonstrated the higher osteoinductive property of the bFGF content scaffold compared with the scaffold without it. According to the results, the release of bFGF from PCL-PVDF nanofibers increased survival and proliferation rate of the iPSCs, which followed by an increase in its osteogenic differentiation potential. Taking together, PCL-PVDF (bFGF) nanofibrous scaffold demonstrated that can be noted as a promising candidate for treating the bone lesions by tissue engineering products.     

A Comparative Study of Fibroblast Behaviors under Cyclic Stress Stimulus and Static Culture on 3D Patterned Matrix

Mechanical stress and patterned surface of the scaffolds has been recognized as a crucial factor in determining cell functionality and tissue development, which in turn can direct the cell responses. In this study, fibroblasts M-3T3 in three-dimensional (3D) honeycomb patterning Chitosan/Poly(L-Lactic Acid) (CS/PLLA) composites was stimulated by a 15% sinusoidal (1 Hz) strain applied by a biodynamic test instrument. The effects of mechanical stimulus on the cell proliferation and basic Fibroblast Growth Factor (bFGF) secretion were studied in comparison to the non-strain groups and blank control. Results show that fibroblasts are able to sense the mechanical stimulation and respond, resulting in a time dependent increase of bFGF secretion and promoting cell proliferation. Moreover, the cells seeded in the scaffolds showed a higher cell proliferation and bFGF secretion. These findings support the hypothesis that suitable mechanical stimulus has positive effect on fibroblasts, and such a 3D honeycomb patterned scaffold may play a positive role in regulating cell behaviors in vitro.     

Electrospun fibrous mats with high porosity as potential scaffolds for skin tissue engineering

Diffusional limitations of mass transport have adverse effects on engineering tissues that normally have high vascularity and cellularity. The current electrospinning method is not always successful to create micropores to encourage cell infiltration within the scaffold, especially when relatively large-sized pores are required. In this study, a slow rotating frame cylinder was developed as the collector to extend the pore size and increase the porosity of electrospun fibrous scaffolds. Fibrous mats with porosity as high as 92.4% and average pore size of 132.7 microm were obtained. Human dermal fibroblasts (HDFs) were seeded onto these mats, which were fixed on a cell-culture ring to prevent the shrinkage and contraction during the incubation. The viability test indicated that significantly more HDFs were generated on highly porous fibrous mats. Toluidine blue staining showed that the highly porous scaffold provided mechanical support for cells to maintain uniform distribution. The cross-section observations indicated that cells migrated and infiltrated more than 100 microm inside highly porous fibrous mats after 5 d incubation. The immunohistochemistry analysis demonstrated that cells began secreting collagen, which is the main constituent of extracellular matrix. It is supposed that highly porous electrospun fibrous scaffolds could be constructed by this elaboration and may be used for skin tissue engineering.     

Characterization of a new degradable polymer scaffold for regeneration of the dermis

Full thickness skin wounds in humans heal with scars, but without regeneration of the dermis. A degradable poly(urethane urea) scaffold (PUUR), Artelon^Ã?® is already used to reinforce soft tissues in orthopaedics, and for treatment of osteoarthritis of the hand, wrist, and foot. In this paper we have done in vitro experiments followed by in vivo studies to find out whether the PUUR is biocompatible and usable as a template for dermal regeneration. Human dermal fibroblasts were cultured on discs of PUUR, with different macrostructures (fibrous and porous). They adhered to and migrated into the scaffolds, and produced collagen. The porous scaffold was judged more suitable for clinical applications and 4 mm Ã?Â?, 2 mm-thick discs of porous scaffold (12% w/w or 9% w/w polymer solution) were inserted intradermally in four healthy human volunteers. The implants were well tolerated and increasing ingrowth of fibroblasts was seen over time in all subjects. The fibroblasts stained immunohistochemically for procollagen and von Willebrand factor, indicating neocollagenesis and angiogenesis within the scaffolds. The PUUR scaffold may be a suitable material to use as a template for dermal regeneration.     

Microporous Dermal-Mimetic Electrospun Scaffolds Pre-Seeded with Fibroblasts Promote Tissue Regeneration in Full-Thickness Skin Wounds

Electrospun scaffolds serve as promising substrates for tissue repair due to their nanofibrous architecture and amenability to tailoring of chemical composition. In this study, the regenerative potential of a microporous electrospun scaffold pre-seeded with dermal fibroblasts was evaluated. Previously we reported that a 70% collagen I and 30% poly(Ɛ-caprolactone) electrospun scaffold (70:30 col/PCL) containing 160 μm diameter pores had favorable mechanical properties, supported fibroblast infiltration and subsequent cell-mediated deposition of extracellular matrix (ECM), and promoted more rapid and effective in vivo skin regeneration when compared to scaffolds lacking micropores. In the current study we tested the hypothesis that the efficacy of the 70:30 col/PCL microporous scaffolds could be further enhanced by seeding scaffolds with dermal fibroblasts prior to implantation into skin wounds. To address this hypothesis, a Fischer 344 (F344) rat syngeneic model was employed. In vitro studies showed that dermal fibroblasts isolated from F344 rat skin were able to adhere and proliferate on 70:30 col/PCL microporous scaffolds, and the cells also filled the 160 μm pores with native ECM proteins such as collagen I and fibronectin. Additionally, scaffolds seeded with F344 fibroblasts exhibited a low rate of contraction (~14%) over a 21 day time frame. To assess regenerative potential, scaffolds with or without seeded F344 dermal fibroblasts were implanted into full thickness, critical size defects created in F344 hosts. Specifically, we compared: microporous scaffolds containing fibroblasts seeded for 4 days; scaffolds containing fibroblasts seeded for only 1 day; acellular microporous scaffolds; and a sham wound (no scaffold). Scaffolds containing fibroblasts seeded for 4 days had the best response of all treatment groups with respect to accelerated wound healing, a more normal-appearing dermal matrix structure, and hair follicle regeneration. Collectively these results suggest that microporous electrospun scaffolds pre-seeded with fibroblasts promote greater wound-healing than acellular scaffolds.     

Melatonin delivery from PCL scaffold enhances glycosaminoglycans deposition in human chondrocytes – Bioactive scaffold model for cartilage regeneration

The therapeutic potential of an engineered cartilage construct can be enhanced by sustained delivery of chondrogenic drug like melatonin from 3D porous scaffolds embedded with melatonin loaded bovine serum albumin nanoparticles (MNP). In this study, MNP was synthesized and loaded into polycaprolactone (PCL) scaffolds. 12 % (w/v) and 10 % (w/v) PCL scaffolds were fabricated with different concentrations of MNP. X- ray diffraction and Raman analysis of MNP and scaffolds revealed amorphization of melatonin which is highly desired in drug delivery applications. Additionally, Fourier Transform Infrared spectroscopic analysis confirmed the drug to be chemically inert to fabrication process. Field emission scanning electron microscopic analysis suggested highly interlinked porous scaffold (diameter 50 μm – 300 μm) and MNP diameters in the range of 110−200 nm. Importantly, UV spectrophotometric analysis showed that all groups of scaffolds showed sustained release for 21 days, wherein MNP concentration had an influence on release behaviour of melatonin from scaffolds. Drug release kinetics studied using mathematical models revealed, diffusion and dissolution mechanism of release. Furthermore, in vitro evaluation of MNP loaded scaffolds with Human chondrocytes for 21 days increased glycosaminoglycans deposition significantly. In brief, sustained release of melatonin from polycaprolactone scaffolds increased the therapeutic potential of the engineered construct.     

Biomacromolecules electrostatic self-assembly on 3-dimensional tissue engineering scaffold

A poly(ethylenimine) (PEI) was employed to obtain a stable positively charged surface on a poly(D,L-lactide) (PDL-LA) tissue engineering scaffold. An extracellular matrix (ECM)-like biomacromolecule, gelatin, was selected as polyelectrolyte and deposit alternately with PEI on the activated PDL-LA scaffold via ESA technique. The zeta-potential result showed alternating charge of polyelectrolytes (PEI/gelatin) layering on PDL-LA microspheres. Quartz crystal microbalance (QCM) measurement further verified the gradual deposition of PEI/gelatin on the PDL-LA thin film. The combination of PEI aminolysis and the layer-by-layer technique was then explored to construct gelatin coating onto the 3-D porous PDL-LA scaffold. Scanning electronic microscopy showed that there is no notable difference between modified and unmodified PLA scaffolds, with regard to the porosity, pore diameter, and scaffold integration. The dual-tunnel confocal laser scanning microscopy indicated uniform gelatin distribution on the inner surface of the 3-D porous scaffold. The gradual build-up of protein layer on scaffold was investigated by radioiodination technique. Chondrocyte was chosen to test the cell behavior on modified and unmodified PDL-LA scaffolds. The results of the cell viability, total intracellular protein content, and cell morphology on the PEI/gelatin multilayers modified PDL-LA scaffold showed to promote chondrocyte growth. Comparing conventional coating methods, polyelectrolyte multilayers are easy and stable to prepare. It may be a promising choice for the surface modification of complex biomedical devices. These very flexible systems allow broad medical applications for drug delivery and tissue engineering.     

Mesenchymal stromal cell‐derived factors promote the colonization of collagen 3D scaffolds with human skin cells

The development of stem cell technology in combination with advances in biomaterials has opened new ways of producing engineered tissue substitutes. In this study, we investigated whether the therapeutic potential of an acellular porous scaffold made of type I collagen can be improved by the addition of a powerful trophic agent in the form of mesenchymal stromal cells conditioned medium (MSC‐CM) in order to be used as an acellular scaffold for skin wound healing treatment. Our experiments showed that MSC‐CM sustained the adherence of keratinocytes and fibroblasts as well as the proliferation of keratinocytes. Moreover, MSC‐CM had chemoattractant properties for keratinocytes and endothelial cells, attributable to the content of trophic and pro‐angiogenic factors. Also, for the dermal fibroblasts cultured on collagen scaffold in the presence of MSC‐CM versus serum control, the ratio between collagen III and I mRNAs increased by 2‐fold. Furthermore, the gene expression for α‐smooth muscle actin, tissue inhibitor of metalloproteinase‐1 and 2 and matrix metalloproteinase‐14 was significantly increased by approximately 2‐fold. In conclusion, factors existing in MSC‐CM improve the colonization of collagen 3D scaffolds, by sustaining the adherence and proliferation of keratinocytes and by inducing a pro‐healing phenotype in fibroblasts.     

Porosity and pore size regulate the degradation product profile of polylactide

Porosity and pore size regulated the degradation rate and the release of low molar mass degradation products from porous polylactide (PLA) scaffolds. PLA scaffolds with porosities above 90% and different pore size ranges were subjected to hydrolytic degradation and compared to their solid analog. The solid film degraded fastest and the degradation rate of the porous structures decreased with decreasing pore size. Degradation products were detected earlier from the solid films compared to the porous structures as a result of the additional migration path within the porous structures. An intermediate degradation rate profile was observed when the pore size range was broadened. The morphology of the scaffolds changed during hydrolysis where the larger pore size scaffolds showed sharp pore edges and cavities on the scaffold surface. In the scaffolds with smaller pores, the pore size decreased during degradation and a solid surface was formed on the top of the scaffold. Porosity and pore size, thus, influenced the degradation and the release of degradation products that should be taken into consideration when designing porous scaffolds for tissue engineering.     

Effects of cell-seeding methods of human osteoblast culture on biomechanical properties of porous bioceramic scaffold

Many studies have been performed to accelerate osteoinduction and osteoconduction into porous ceramic scaffolds by seeding them with cells. In this study, we compared available cell-seeding methods on a porous β-tricalcium phosphate (β-TCP) scaffold and evaluated the effects of cell-seeding on the mechanical properties of the porous β-TCP scaffold. Three types of porous bioceramic scaffolds were used: dry scaffold, scaffold wetted with media, and scaffold cultivated with normal human osteoblasts (NHOs). Cell-seeding into the porous β-TCP scaffolds was performed by conventional, centrifuge, high-density, and vacuum methods. After confirming cell proliferation with MTT assay and cell staining, a compressive test was performed after 2 and 4 weeks of cell culture. The vacuum method based on the high-density cell culture inserted effectively NHOs into the β-TCP scaffolds. The compressive elastic modulus of wetted β-TCP scaffolds decreased significantly (p < 0.05) about 20∼30% after 2 and 4 weeks of incubation in comparison with that of the dry scaffold. However, the compressive strength of the scaffolds cultivated with NHOs for 3 weeks was significantly (p < 0.05) higher than that of scaffolds without NHOs. The vacuum with the high-density of cell-seeding seems to be a suitable method for seeding cells into complex porous ceramic scaffolds. Cell proliferation and uniform distribution in the scaffolds can change the initial mechanical properties of porous ceramic scaffolds.     

Bioactive nanofibers for fibroblastic differentiation of mesenchymal precursor cells for ligament/tendon tissue engineering applications

Mesenchymal stem cells and precursor cells are ideal candidates for tendon and ligament tissue engineering; however, for the stem cell-based approach to succeed, these cells would be required to proliferate and differentiate into tendon/ligament fibroblasts on the tissue engineering scaffold. Among the various fiber-based scaffolds that have been used in tendon/ligament tissue engineering, hybrid fibrous scaffolds comprising both microfibers and nanofibers have been recently shown to be particularly promising. With the nanofibrous coating presenting a biomimetic surface, the scaffolds can also potentially mimic the natural extracellular matrix in function by acting as a depot for sustained release of growth factors. In this study, we demonstrate that basic fibroblast growth factor (bFGF) could be successfully incorporated, randomly dispersed within blend-electrospun nanofibers and released in a bioactive form over 1 week. The released bioactive bFGF activated tyrosine phosphorylation signaling within seeded BMSCs. The bFGF-releasing nanofibrous scaffolds facilitated BMSC proliferation, upregulated gene expression of tendon/ligament-specific ECM proteins, increased production and deposition of collagen and tenascin-C, reduced multipotency of the BMSCs and induced tendon/ligament-like fibroblastic differentiation, indicating their potential in tendon/ligament tissue engineering applications.     

Novel Biodegradable Porous Scaffold Applied to Skin Regeneration

Skin wound healing is an important lifesaving issue for massive lesions. A novel porous scaffold with collagen, hyaluronic acid and gelatin was developed for skin wound repair. The swelling ratio of this developed scaffold was assayed by water absorption capacity and showed a value of over 20 g water/g dried scaffold. The scaffold was then degraded in time- and dose-dependent manners by three enzymes: lysozyme, hyaluronidase and collagenase I. The average pore diameter of the scaffold was 132.5±8.4 µm measured from SEM images. With human skin cells growing for 7 days, the SEM images showed surface fractures on the scaffold due to enzymatic digestion, indicating the biodegradable properties of this scaffold. To simulate skin distribution, the human epidermal keratinocytes, melanocytes and dermal fibroblasts were seeded on the porous scaffold and the cross-section immunofluorescent staining demonstrated normal human skin layer distributions. The collagen amount was also quantified after skin cells seeding and presented an amount 50% higher than those seeded on culture wells. The in vivo histological results showed that the scaffold ameliorated wound healing, including decreasing neutrophil infiltrates and thickening newly generated skin compared to the group without treatments.     

担载b-FGF的PLGA微球复合明胶支架的体外释放研究

目的:研究担载碱性成纤维细胞生长因子(b-FGF)微球复合明胶支架的外形特征、孔径、孔隙率及体外释放动力学,以期构建具有缓释功能、高孔隙率的担载细胞因子的新型复合明胶支架。方法:本文利用冷冻相分离法和S/O/W法先将b-FGF水溶液包裹于PLGA微球中,然后埋置于明胶溶液中制备为多孔复合明胶支架。分别对微球的形态和复合明胶支架的基本形态、孔径、孔隙率进行表征,通过Elisa法测定b-FGF在复合明胶支架中的体外释放行为。结果:制备成形态良好的三维复合明胶支架,其孔隙率为82.90%±1.45%,孔径范围为150~300μm,复合明胶支架中b-FGF在体外缓慢释放20余天。结论:担载蛋白微球复合明胶支架不仅满足组织工程支架的要求,还能有效缓释细胞因子,为细胞和组织生长提供良好的微环境,为进一步应用于组织工程领域提供了可能。     

Effects of gel concentration, human fibronectin, and cation supplement on the tissue-engineered cartilage

Cultivation of bovine knee chondrocytes (BKCs) in various cationic additives was studied using chitosan-gelatin scaffolds, whose surfaces were modified by human fibronectin (HFN). Here, the genipin-crosslinked scaffolds were fabricated by the freezing/lyophilization method with various concentrations of the precursory gels. The experimental results indicated that a lower freezing temperature led to higher moisture content, porosity, and specific surface area of a scaffold. The higher the precursor concentration, the larger the moisture content of a scaffold. A fast biodegradation of scaffold matrix was generated by a high porosity with BKCs. A higher concentration of HFN coated on scaffold surfaces yielded a faster rate of BKC attachment from the culture medium. The amounts of BKCs, glycosaminoglycans, and collagen over 28-day cultivation increased with the scaffold porosity, the coating concentration of HFN, the seeding density of BKCs, and the calcium concentration in medium.     

Porous bioactive glass scaffolds for local drug delivery in osteomyelitis: development and in vitro characterization

A new bioactive glass-based scaffold was developed for local delivery of drugs in case of osteomyelitis. Bioactive glass having a new composition was prepared and converted into porous scaffold. The bioactivity of the resulting scaffold was examined by in vitro acellular method. The scaffolds were loaded with two different drugs, an antibacterial or antifungal drug. The effects of the size of the scaffold, drug concentration, and dissolution medium on drug release were studied. The scaffolds were further coated with a degradable natural polymer, chitosan, to further control the drug release. Both the glass and scaffold were bioactive. The scaffolds released both the drugs for 6 weeks, in vitro. The results indicated that the bigger the size and the higher the drug concentration, the better was the release profile. The scaffolds appeared to be suitable for local delivery of the drugs in cases of osteomyelitis.