Protective Effect of Low-Molecular-Weight Fucoidan on Radiation-Induced Fibrosis Through TGF-ß1/Smad Pathway-Mediated Inhibition of Collagen I Accumulation.

Radiation-induced fibrosis (RIF) occurs after radiation therapy in normal tissues due to excessive production and deposition of extracellular matrix proteins and collagen, possibly resulting in organ function impairment. This study investigates the effects of low-molecular-weight fucoidan (LMF) on irradiated NIH3T3 cells. Specifically, we quantified cellular metabolic activity, fibrosis-related mRNA expression, transforming growth factor beta-1 (TGF-ß1), and collagen-1 protein expression, and fibroblast contractility in response to LMF. LMF pre + post-treatment could more effectively increase cellular metabolic activity compared with LMF post-treatment. LMF pre + post-treatment inhibited TGF-ß1 expression, which mediates negative activation of phosphorylated Smad3 (pSmad3) and Smad4 complex formation and suppresses downstream collagen I accumulation. In addition, LMF pre + post-treatment significantly reduced actin-stress fibers in irradiated NIH3T3 cells. LMF, a natural substance obtained from brown seaweed, may be a candidate agent for preventing or inhibiting RIF.

Biodegradation of three tetracyclines in swine wastewater.

Tetracyclines (TCs), including tetracycline (TC), oxytetracycline (OTC), and chlortetracycline (CTC), are amongst the most common antibiotics used in animal husbandry. Residual amounts of these antibiotics in the environment are a concern because they contribute to selection of resistant bacteria. In this study, we investigated the biodegradation of three TCs in swine wastewater. In batch experiments, OTC and CTC were completely degraded at d 18 and 20, respectively, but TC was remained at 7.1% after 20 d incubation. The degradation rates of TCs in the wastewater were in the order of OTC > CTC > TC. Degradation of the TCs was enhanced by the addition of enzyme extract from spent mushroom compost (SMC) of Pleurotus eryngii. The degradation rates were higher with the addition of extract-containing microcapsules than suspended enzyme extract in swine wastewater. In the bioreactor experiment, the addition of extract-containing microcapsules enhanced the removal rates of the three TCs, and adding TCs twice maintained enzyme activity in the swine wastewater. Of the microorganism strains isolated from the wastewater samples, strain HL2 (identified as Xanthobacter flavus) showed the best degrading ability.

Development of pH-sensitive pectinate/alginate microspheres for colon drug delivery.

The purposes of this study were to develop and evaluate calcium pectinate/alginate microspheres (PAMs) and to exploit their pH-sensitive properties for colon-targeted delivery of encapsulated cisplatin. PAMs were prepared using an electrospraying method. The PAMs, as cores, were then coated with Eudragit S100 using a polyelectrolyte multilayer coating technique in aqueous solution. The morphology of the microspheres was observed under scanning electron microscopy. In vitro drug release studies were performed in simulated gastrointestinal fluid, and the results indicated that approximately 5 % of the cisplatin was released from the Eudragit S100-coated PAMs, and 51 % of the cisplatin was released from the uncoated PAMs at 1 h. The release of cisplatin from the Eudragit S100-coated PAMs was more sustained in simulated gastric fluid than in simulated intestinal fluid due to the increased solubility of the coating polymer in media with pH >7.0. Drug release from the Eudragit S100-coated PAMs was best described by the Higuchi's square root model. From these results, it was concluded that Eudragit S100-coated PAMs are a potential carrier for delivery of cisplatin to the colon.

Electrospun nanofiber composite mat based on ulvan for wound dressing applications.

Wound dressings can be used to create a temporary healing environment and expedite the wound healing process. Ulvan (ULV) is a sulfated polysaccharide with potent antiviral and anti-inflammatory activities. Polycaprolactone (PCL) is a hydrophobic biodegradable polyester that exhibits slow degradation, strong mechanical strength, and excellent biocompatibility. Electrospun nanofiber matrices mimic the microstructure of the extracellular matrix, allowing them to promote cell proliferation and differentiation. Therefore, the primary objective of this study was to fabricate a polycaprolactone-ulvan fibrous composite mat (PCL-ULV) using the electrospinning technique and to investigate its physical and chemical properties. To assess the characteristics of PCL-ULV, scanning electron microscopy (SEM) was utilized to examine its morphology and diameter distribution. Fourier transform infrared (FTIR) spectroscopy, calcofluor white staining, and monosaccharide analysis were employed to analyze the components of PCL-ULV. Additionally, the water contact angle was measured to evaluate the hydrophilicity. Furthermore, the proliferation and morphology of and gene expression in NIH3T3 fibroblasts on PCL-ULV were assessed. The results showed that the average PCL-ULV fiber diameter was significantly smaller than that of the PCL fibers. The water contact angle measurements indicated that PCL-ULV exhibited better hydrophilicity than the PCL mat. FTIR, calcofluor white staining, and monosaccharide analyses demonstrated that ULV could be successfully coelectrospun with PCL. NIH3T3 fibroblasts cultured on PCL and PCL-ULV showed different cellular behaviors. On PCL-ULV, cell adhesion, proliferation, and stretching were greater than those on PCL. Moreover, the behavior of NIH3T3 fibroblasts on PCL and PCL-ULV differed, as the cells on PCL-ULV exhibited higher proliferation and more stretching. Furthermore, NIH3T3 fibroblasts cultured on ULV-PCL showed higher α-SMA and MMP-9 gene expression and a lower ratio of TIMP-1/MMP-9 than those cultured on PCL. Notably, scarless wounds display lower TIMP/MMP expression ratios than scarring wounds. Thus, the fibrous composite mat PCL-ULV shows potential as a wound dressing for scarless wound healing.

Preparation and characterization of mesoporous bioactive glass/polycaprolactone nanofibrous matrix for bone tissues engineering.

A polycaprolactone (PCL) nanofibrous composite matrix having mesoporous bioactive glass nanoparticles (MBG) was fabricated using the electrospinning method, and the microstructural, physical and biological properties of the composite matrix were characterized. The fiber diameters of PCL, 5 % MBG/PCL (5 M-PCL) and 10 % MBG/PCL (10 M-PCL) were 575 ± 162 nm, 312 ± 134 nm and 321 ± 144 nm, respectively. The bioactivity of the composite matrix was evaluated by soaking the matrix in 1.5× simulated body fluid; the MBG/PCL matrix showed a better biomineralization capability than did the PCL matrix. The biological performance of the PCL and the MBG/PCL were evaluated using an in vitro culture of MG63 osteoblast-like cells. We found that the cell attachment and proliferation rates were significantly higher on the 10 M-PCL than on the PCL. Moreover, the expression of several genes, including ANX-V, type I collagen and OCN, ALP activity, the deposition of calcium, and the BSP protein, were also significantly higher on 10 M-PCL than PCL. These results indicated that MBG/PCL has the ability to support cell attachment, growth, and differentiation and can also yield high bioactivity. Therefore, MBG/PCL could be potentially applied in bone implants.

Influence of the Components and Orientation of Hydroxyapatite Fibrous Substrates on Osteoblast Behavior.

Synthetic hydroxyapatite has good biocompatibility, bioactivity and osteoconductive ability because its chemical properties and biological properties are similar to those of bioapatite in bone tissue. Strontium-substituted hydroxyapatite has better degradability than hydroxyapatite and can both promote osteogenesis and inhibit adipogenesis in mesenchymal stem cells. Hence, hydroxyapatite and strontium-substituted hydroxyapatite are widely used as bone graft materials, cell carriers and drug/gene delivery carriers. In addition, osteoblasts cultured on aligned nanofibrous substrates had higher expression of osteogenesis-related genes than did those cultured on random nanofibrous substrates. However, to date, no study has explored the effects of the components and orientation of hydroxyapatite nanofibrous substrates on osteoblastic behavior. In this study, a random hydroxyapatite nanofibrous substrate (R-HANF), a random strontium-substituted hydroxyapatite nanofibrous substrate (R-SrHANF), an aligned hydroxyapatite nanofibrous substrate (A-HANF) and an aligned strontium-substituted hydroxyapatite nanofibrous substrate (A-SrHANF) were successfully fabricated by using the electrospinning technique. The effect of fiber composition on osteoblast-like MG63 cells was assessed by evaluating cell morphology, cell proliferation and osteogenesis-related gene expression. The results showed that MG63 cells cultured on A-SrHANF had higher osteogenesis-related gene expression than those cultured on A-HANF. Additionally, MG63 cells were cultured on R-SrHANF and A-SrHANF to evaluate the effects of fiber orientation on cell behavior. On A-SrHANF, the cells aligned along the direction of the nanofibers, with typical bipolar morphologies, and exhibited higher osteogenesis-related gene expression than cells on R-SrHANF. Hence, the components and orientation of hydroxyapatite nanofibrous substrates are critical parameters affecting the osteogenesis process.

The Effect of Strontium-Substituted Hydroxyapatite Nanofibrous Matrix on Osteoblast Proliferation and Differentiation.

Natural bone tissue consists primarily of bioapatite and collagen. Synthetic hydroxyapatite (HA) possesses good biocompatibility, bioactivity, and osteoconductivity due to its chemical and biological similarity to bioapatite. Hence, HA has been widely used as a bone graft, cell carrier and drug/gene delivery carrier. Moreover, strontium-substituted hydroxyapatite (SrHA) can enhance osteogenic differentiation and inhibit adipogenic differentiation of mesenchymal stem cells. Hence, SrHA has the potential to be used as a bone graft for bone regeneration. It is widely accepted that cell adhesion and most cellular activities are sensitive to the topography and molecular composition of the matrix. Electrospun polymer or polymer-bioceramic composite nanofibers have been demonstrated to enhance osteoblast differentiation. However, to date, no studies have investigated the effect of nanofibrous bioceramic matrices on osteoblasts. In this study, hydroxyapatite nanofiber (HANF) and strontium-substituted hydroxyapatite nanofiber (SrHANF) matrices were fabricated by electrospinning. The effect of the HANF components on MG63 osteoblast-like cells was evaluated by cell morphology, proliferation, alkaline phosphatase activity (ALP) and gene expression levels of RUNX2, COLI, OCN and BSP. The results showed that MG63 osteoblast-like cells exhibited higher ALP and gene expression levels of RUNX2, COLI, BSP and OCN on the SrHANF matrix than the HANF matrix. Hence, SrHANFs could enhance the differentiation of MG63 osteoblast-like cells.

Preparation of a Fucoidan-Grafted Hyaluronan Composite Hydrogel for the Induction of Osteoblast Differentiation in Osteoblast-Like Cells.

A suitable bone substitute is necessary in bone regenerative medicine. Hyaluronan (HA) has excellent biocompatibility and biodegradability and is widely used in tissue engineering. Additionally, research on fucoidan (Fu), a fucose- and sulfate-rich polysaccharide from brown seaweed, for the promotion of bone osteogenic differentiation has increased exponentially. In this study, HA and Fu were functionalized by grafting methacrylic groups onto the backbone of the chain. Methacrylate-hyaluronan (MHA) and methacrylate-fucoidan (MFu) were characterized by FTIR and 1H NMR spectroscopy to confirm functionalization. The degrees of methacrylation (DMs) of MHA and MFu were 9.2% and 98.6%, respectively. Furthermore, we evaluated the mechanical properties of the hydrogels formed from mixtures of photo-crosslinkable MHA (1%) with varying concentrations of MFu (0%, 0.5%, and 1%). There were no changes in the hardness values of the hydrogels, but the elastic modulus decreased upon the addition of MFu, and these mechanical properties were not significantly different with or without preosteoblastic MG63 cell culture for up to 28 days. Furthermore, the cell morphologies and viabilities were not significantly different after culture with the MHA, MHA-MFu0.5, or MHA-MFu1.0 hydrogels, but the specific activity and mineralization of alkaline phosphatase (ALP) were significantly higher in the MHA-MFu1.0 hydrogel group compared to the other hydrogels. Hence, MHA-MFu composite hydrogels are potential bone graft materials that can provide a flexible structure and favorable niche for inducing bone osteogenic differentiation.

Single-photon and two-photon cellular imagings of gold nanorods and dyes.

A method to obtain the expressions of gold nanorods (GNRs) and dye molecules simultaneously is proposed for the single-photon and two-photon cellular imagings by using laser scanning confocal microscopy. For our experiment, GNRs with an average aspect ratio of 2.14 were synthesized using electrochemical method, and the peak of absorption spectrum of GNRs is at 600 nm. The human breast cancer cell lines (MDA-MB-435) were studied by incubating them with GNRs for 20 hours and then staining their nuclei with dye molecules-Prodium Iodide (PI). For the single-photon imaging, different CW lasers (458, 488, 514, 561, and 633 nm) were used individually to irradiate the samples. By adjusting the ranges of two bandpass filters for the detection, the scattered light from the GNRs due to surface plasmon resonance (SPR) and the fluorescence from PI can be induced simultaneously but be detected separately without crosstalk. Furthermore, the two cellular images can be merged together to become a composited cellular image. The TEM image shows that several clusters of GNRs internalized by the vesicles are distributed sparsely inside the cytoplasm, due to the endocytosis of the cells. The aggregation of GNRs causes SPR band broadened. Therefore strong scattered light from GNRs can almost be induced by different-wavelength lasers irradiating. However, the expression of PI can only be detected by the exciting lasers with a wavelength shorter than 600 nm. For the two-photon imaging of these cells internalizing GNRs, an ultrafast Ti:Sapphire IR-laser (800 nm) was used for irradiating the sample, and two bandpass filters were also adjusted to distinguish the photoluminescence of GNRs from the fluorescence of PI.

Collagen Scaffolds Containing Hydroxyapatite-CaO Fiber Fragments for Bone Tissue Engineering.

Collagen (COL) and hydroxyapatite (HAp) are the major components of bone, therefore, COL-HAp composites have been widely used as bone substitutes to promote bone regeneration. We have reported that HAp-CaO fibers (HANFs), which were fabricated by a sol-gel route followed by an electrospinning technique, possessed good drug-loading efficiency and limited the burst release of tetracycline. In the present study, we used HANF fragments to evaluate the effects of COL-HANF scaffolds on MG63 osteoblast-like cell behaviors. COL-HANF composite scaffolds in which the average diameter of HANFs was approximately 461 ± 186 nm were fabricated by a freeze-drying process. The alkaline phosphatase activity and the protein expression levels of OCN and BSP showed that compared with COL alone, the COL-HANF scaffold promoted the differentiation of MG63 osteoblast-like cells. In addition, the bone regeneration ability of the COL-HANF scaffold was examined by using a rabbit condylar defect model in vivo. The COL-HANF scaffold was biodegradable and promoted bone regeneration eight weeks after the operation. Hence, we concluded that the COL-HANF scaffold has potential as a bone graft for bone tissue engineering.

Surface plasmon effects on two photon luminescence of gold nanorods.

Gold nanorods emit strong photoluminescence under two photon excitation; the efficient two photon lumininescence (TPL) arises from the local field enhancement assisted by surface plasmons. The surface plasmon effects on the TPL efficiency and spectrum are investigated by measuring the TPL of gold nanorods with various aspect ratios. A large TPL efficiency is found when incident light wavelength coincides with the longitudinal surface plasmon mode of the gold nanorods. However, the emission spectra of nanorods with various aspect ratios look similar and exhibit modest surface plasmon features, which implies a major non-radiative decay of excited surface plasmons.

Fabrication of polycaprolactone tubular scaffolds with an orthogonal-bilayer structure for smooth muscle cells.

In this study, we used electrospinning to prepare a bilayered polycaprolactone (PCL) tubular graft consisting of an internal layer comprising axial nanofibers and an external layer comprising circumferentially aligned nanofibers. Subsequently, the surfaces of the electrospun PCL tubular scaffolds were modified with 1,6-diaminohexane to introduce amino groups and were then chemically conjugated with gelatin (Gel). The amino groups and Gel were successfully immobilized on the PCL scaffolds according to a ninhydrin assay, attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopic analysis and contact angle analysis. Additionally, vascular smooth muscle cells (vSMCs, A7r5) were cultured on random and aligned Gel-PCL scaffolds to evaluate the effects of fiber orientation on cell behavior. The results of immunofluorescence analysis showed that vSMCs on the aligned Gel-PCL scaffolds exhibited a pro-contractile phenotype.

Fabrication and Characteristics of PCL Membranes Containing Strontium-Substituted Hydroxyapatite Nanofibers for Guided Bone Regeneration.

Poly(ε-caprolactone) (PCL) membranes have been widely used in guided tissue regeneration (GTR) and guided bone regeneration (GBR). In addition, hydroxyapatite is the major inorganic component and an essential composition of hard bone and teeth. Recently, numerous studies have demonstrated that strontium-substituted hydroxyapatite (SrHA) not only enhances osteogenesis but also inhibits adipogenesis of mesenchymal stem cells. Therefore, SrHA incorporated into PCL could be an alternative material for GBR. In this study, strontium-substituted hydroxyapatite nanofibers (SrHANFs) were fabricated by a sol-gel route followed by electrospinning. We then fabricated PCL-SrHANF membranes as cell culture substrates and assessed the cellular behavior of osteoblast-like cells. Based on the observations of alkaline phosphatase (ALP) activity, bone sialoprotein (BSP) and osteocalcin (OCN) immunofluorescence staining, and Alizarin Red-S staining of cells cultured on the PCL-SrHANF and PCL membranes, we concluded that SrHANFs can promote the differentiation and mineralization of osteoblast-like cells and that PCL-SrHANF membranes have potential for GBR applications.

Beads of collagen-nanohydroxyapatite composites prepared by a biomimetic process and the effects of their surface texture on cellular behavior in MG63 osteoblast-like cells.

The aim of this work was to develop a novel method for preparing a three-dimensional bone-like matrix comprising nanohydroxyapatite crystals and fibrous collagen and to apply it for bone tissue engineering. Hydroxyapatite and collagen are the major components of natural hard bone. Therefore, they have been used extensively in orthopedic surgery as bone-filling materials. According to the principle of complex coacervation, three-dimensional collagen beads can be formed by extruding collagen solution into chondroitin sulfate A (CSA) solution. Subsequently, the collagen beads thus formed are soaked in simulated body-fluid solution to biomimic the formation process of natural bone matrix via the fabrication of collagen-nanohydroxyapatite beads. We also investigate the effect of the collagen-nanohydroxyapatite matrix on the proliferation and differentiation of MG63 cells. The presence of crystalline hydroxyapatite structure on the surface of fibrous collagen was confirmed by X-ray diffraction. MG63 cells cultured on the collagen-nanohydroxyapatite beads proliferate at the normal rate. Moreover, alkaline phosphatase (ALP) activity and the expression levels of three osteogenic genes, namely, type I collagen osteopontin and osteocalcin, in MG63 cells were significantly higher when the cells were cultured on collagen-nanohydroxyapatite beads than when they were cultured on collagen alone. The results of this study reveal that, in the presence of nanohydroxyapatite, the three-dimensional cell beads not only provide a substrate for cell growth but could also enhance the osteoblast-like cell differentiation of MG63 cells.

Surface-Modified Gold Nanoparticles with Folic Acid as Optical Probes for Cellular Imaging.

In this study, we demonstrate that the uptake rate of the surface-modified gold nanoparticles (GNPs) with folic acid by specific cells can be increased significantly, if the membranes of these cells have sufficient folic-acid receptors. Two human breast cancer cell lines were studied; one is MDA-MB-435S cell, and the other T-47D cell. The expression of the folic acid receptors of the former is much higher than that of the latter. These cells were incubated with media containing bare GNPs or GNPs conjugated with folic acid individually. Due to the unique optical behavior (i.e. surface plasmon resonance) of GNPs, the uptake amount of GNPs by cells can be identified by using the laser scanning confocal microscopy. Our experiments show that the uptake amount of GNPs in MDAMB-435S cells is higher than that in T-47D cells for the same culture time, if the culture medium contains bare GNPs. Moreover, if the GNPs conjugated with folic acid are used for the culture, the uptake rate of GNPs by MDA-MB-435S cells is improved more. In contrast, the uptake rates of both GNPs are almost the same by T-47D cells. The phenomenon indicates that the uptake rate of GNPs can be improved via the ligand-receptor endocytosis, compared with the nonspecific endocytosis. Therefore, the uptake rate of GNPs conjugated with folic acid by MDA-MB-435S cells is higher than that of bare GNPs.

Fabrication and Characteristics of Porous Hydroxyapatite-CaO Composite Nanofibers for Biomedical Applications.

Hydroxyapatite (HAp), a major inorganic and essential component of normal bone and teeth, is a promising biomaterial due to its excellent biocompatibility, bioactivity, and osteoconductivity. Therefore, synthetic HAp has been widely used as a bone substitute, cell carrier, and delivery carrier of therapeutic genes or drugs. Mesoporous materials have attracted considerable attention due to their relatively high surface area, large pore volume, high porosity, and tunable pore size. Recently, mesoporous HAp has also been successfully synthesized by the traditional template-based process and has been demonstrated to possess better drug-loading and release efficiencies than traditional HAp. It is widely accepted that cell adhesion and most cellular activities, including spreading, migration, proliferation, gene expression, surface antigen display, and cytoskeletal functioning, are sensitive to the topography and molecular composition of the matrix. The native extracellular matrix is a porous, nanofibrous structure. The major focus of this study is the fabrication of porous hydroxyapatite-CaO composite nanofibers (p-HApFs) and the investigation of its drug-release property. In this study, nanofibers were prepared by the sol-gel route and an electrospinning technique to mimic the three-dimensional structure of the natural extracellular matrix. We analyzed the components of fibers using X-ray diffraction and determined the morphology of fibers using scanning and transmission electron microscopy. The average diameter of the nanofibers was approximately 461 ± 186 nm. The N2 adsorption⁻desorption isotherms were type IV isotherms. Moreover, p-HApFs had better drug-loading efficiency and could retard the burst release of tetracycline and maintain antibacterial activity for a period of 7 days. Hence, p-HApFs have the potential to become a new bone graft material.

Macroporous microbeads containing apatite-modified mesoporous bioactive glass nanofibres for bone tissue engineering applications.

Mesoporous bioactive glass (MBG) has a greater surface area and pore volume than conventional BG. Hence, MBG is useful as a drug delivery carrier. Previously, MBG has been fabricated as dense or porous blocks. Compared to blocks, microbeads have a greater flexibility to fill different-shaped cavities with close packing. Moreover, fibrous materials have proven to increase cell attachment and differentiation because they mimic the three-dimensional structure of the natural extracellular matrix (ECM). Macroporous materials possess porous structures with interconnecting channels that allow the invasive growth of cells and capillaries. Hence, the aim of this study was to fabricate macroporous microbeads containing MBG nanofibres (MMBs). We used poly(methyl methacrylate) (PMMA) microspheres as the macroporous template in the process and removed the PMMA microspheres after the calcination treatment. Scanning electron microscopy imaging showed multiple pores on the surface of the MMBs, and a micro-computed tomography image showed the presence of pores throughout the entire microbead. The cellular attachment of MG63 osteoblast-like cells was considerably higher on the MMBs than on glass beads after culturing for 4 h. However, the cell viability greatly decreased after culturing for 1 day. We speculated that the release of a high concentration of calcium ions from the MMBs decreased the cell viability. To improve the cell viability, we modified the MMBs by immersing the MMBs in a simulated body fluid to fabricate a thin apatite layer on the surface of the MMBs. The apatite-modified MMBs (Ap-MMB) decreased the release of calcium ions and improved the cell viability. In an animal study, the bone defect in the control group did not recover. In contrast to the control group, the Ap-MMBs in the defect were nearly filled with new bone. The results show that the Ap-MMBs have great potential in osteogenesis for bone tissue engineering.

Fabrication and Characterization of Strontium-Substituted Hydroxyapatite-CaO-CaCO3 Nanofibers with a Mesoporous Structure as Drug Delivery Carriers.

Hydroxyapatite (HAp) is the main inorganic component and an essential part of hard bone and teeth. Due to its excellent biocompatibility, bioactivity, and osteoconductivity, synthetic HAp has been widely used as a bone substitute, cell carrier, and therapeutic gene or drug carrier. Recently, numerous studies have demonstrated that strontium-substituted hydroxyapatite (SrHAp) not only enhances osteogenesis but also inhibits adipogenesis in mesenchymal stem cells. Mesoporous SrHAp has been successfully synthesized via a traditional template-based process and has been found to possess better drug loading and release efficiencies than SrHAp. In this study, strontium-substituted hydroxyapatite-CaO-CaCO3 nanofibers with a mesoporous structure (mSrHANFs) were fabricated using a sol⁻gel method followed by electrospinning. X-ray diffraction analysis revealed that the contents of CaO and CaCO3 in the mSrHANFs decreased as the doping amount of Sr increased. Scanning electron microscopy (SEM) images showed that the average diameter of the mSrHANFs was approximately 200~300 nm. The N2 adsorption⁻desorption isotherms demonstrated that the mSrHANFs possessed a mesoporous structure and that the average pore size was approximately 20~25 nm. Moreover, the mSrHANFs had excellent drug- loading efficiency and could retard the burst release of tetracycline (TC) to maintain antibacterial activity for over 3 weeks. Hence, mSrHANFs have the potential to be used as drug carriers in bone tissue engineering.

Fabrication and Cytotoxicity of Fucoidan-Cisplatin Nanoparticles for Macrophage and Tumor Cells.

Fucoidan, an anionic, sulfated polysaccharide from brown seaweed, is known to exhibit antitumor and immunomodulatory functions. To develop an immune protection and chemotherapeutic agent, fucoidan-cisplatin nanoparticles (FCNPs) were designed. FCNPs were prepared by mixing cisplatin with fucoidan solution or fucoidan with cisplatin solution, followed by dialysis to remove trace elements. The nanoparticles, comprising 10 mg of fucoidan and 2 mg of cisplatin, which exhibited the highest cisplatin content and loading efficiency during the production process, were named as Fu100Cis20. The cisplatin content, cisplatin loading efficiency, nanoparticle size, and zeta potential of Fu100Cis20 were 18.9% ± 2.7%, 93.3% ± 7.8%, 181.2 ± 21.0 nm, and -67.4 ± 2.3 mV, respectively. Immune protection assay revealed that Fu100Cis20-treated RAW264.7 cells were protected from the cytotoxicity of cisplatin. Furthermore, antitumor assay indicated that Fu100Cis20-treated HCT-8 cells showed stronger cytotoxicity than those treated with cisplatin alone. These results suggested that fucoidan-based nanoparticles exhibited suitable particle size and high drug encapsulation, and that Fu100Cis20 has potential application in both immunotherapy and chemotherapy.

Construction of cell-containing, anisotropic, three-dimensional collagen fibril scaffolds using external vibration and their influence on smooth muscle cell phenotype modulation.

Numerous methods have been developed for preparing guiding channels/tracks to promote the alignment of highly oriented cell types. However, these manufacture methods cannot fabricate interconnected guiding channels within three-dimensional (3D) scaffolds. Providing a suitable architectural scaffold for cell attachment could lead cells to more rapidly display a desired phenotype and perform their unique functions. Previously, we developed a simple device composed of a pneumatic membrane that can generate a tunable vibration frequency to apply physical stimulation for fabricating a 3D aligned collagen fibril matrix with the characteristic D-period structure in one step. In the present study, we aimed to evaluate the cellular responses of thoracic aortic smooth muscle cells (A7r5) incorporated during the fabrication of 3D-aligned collagen fibrils with D-periods and compared these cells with those incorporated in a 3D, randomly distributed collagen matrix and in a two-dimensional (2D) aligned substrate after up to 10 days of culture. The results consistently demonstrated that A7r5 cells cultured within the 3D and 2D anisotropic matrices were aligned. Cells cultured in the 3D aligned scaffolds exhibited a higher proliferation rate as well as higher F-actin and smoothelin expression levels compared with cells cultured in 3D randomly distributed scaffolds. Together, these results indicate that a 3D-reconstituted, anisotropic collagen matrix fabricated by our process provides synergistic effects of tension stimulation and matrix stiffness on encapsulated cells and can direct A7r5 cells to transform from a synthetic phenotype into a contractile state.