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1.
ACS Omega ; 9(13): 15372-15382, 2024 Apr 02.
Article in English | MEDLINE | ID: mdl-38585094

ABSTRACT

In this study, we conduct simulation research on simultaneous desulfurization and denitrification in a multistaggered baffle spray scrubber. By employing two-phase flow simulations within the Euler-Lagrange framework and calculating the gas-liquid mass transfer rate with user-defined functions, we comprehensively analyzed the effects of various operational parameters. Initially, we validated our simulation model by comparing the simulation results with experimental data. Under conditions of a 0.2 mm droplet diameter, a liquid-to-gas ratio (L/G) of 12 L/m3, and a gas flow rate of 5 CMM using a full cone nozzle, the simulation indicated a desulfurization efficiency of 99.90 versus 99.84% obtained experimentally and a denitrification efficiency of 92.01 versus 90.67% obtained experimentally. This comparison confirmed the reliability of the simulation model. Our findings indicate that a droplet size of 2 mm is optimal, enhancing the desulfurization efficiency from 99.90 to 99.98% and the denitrification efficiency from 92.01 to 99.76%. However, when the droplet size exceeds 2 mm, efficiencies marginally decrease. Increasing the liquid-to-gas ratio to 16 L/m3 further improves desulfurization and denitrification efficiencies to 99.98 and 99.80%, respectively. In contrast, higher inlet flue gas flow rates reduce these efficiencies, with a decline observed from 100% to as low as 93.90% for denitrification with 2 mm droplets. Additionally, the use of a swirl cone nozzle, compared to full or hollow cone nozzles, better disperses droplets, enhancing the gas-liquid contact and achieving efficiencies of 99.99% for desulfurization and 99.81% for denitrification with 2 mm droplets. These insights are valuable for optimizing operational conditions in industrial-scale spray scrubbers, significantly contributing to mitigating the environmental impacts of industrial emissions.

2.
Membranes (Basel) ; 12(10)2022 Sep 28.
Article in English | MEDLINE | ID: mdl-36295709

ABSTRACT

Due to its greater physical-chemical stability, ceramic nanofiltration (NF) membranes were used in a number of industrial applications. In this study, a novel NF membrane was prepared by co-depositing a titanium dioxide (TiO2) and graphene oxide (GO) composite layer directly onto a porous α-Al2O3 hollow fiber (HF) support. An 8 µm-thick TiO2/GO layer was deposited to the surface of α-Al2O3 HF support by vacuum deposition method to produce advanced TiO2/GO-Al2O3 HF NF membrane. Scanning electron microscope (SEM) micrographs, energy dispersive spectrometer (EDS), X-ray powder diffraction (XRD), thermogravimetric analyzer (TGA), porosity, 3-point bending strength, zeta potential analysis, and hydrophilic properties by water contact angle are used for TiO2/GO-Al2O3 HF NF membrane characterization. The results show that the developed membrane's MWCO ranged from 600 to 800 Da. The water flux, rejection of lignin, and sodium ions were 5.6 L/m2 h·bar, ~92.1%, and ~5.5%, respectively. In a five-day NF process, the TiO2/GO-Al2O3 HF NF membrane exhibits good lignin permeation stability of about 14.5 L/m2 h.

3.
Micromachines (Basel) ; 12(10)2021 Oct 17.
Article in English | MEDLINE | ID: mdl-34683313

ABSTRACT

In this paper we report on the improvement of performance by minimizing scallop size through deep reactive-ion etching (DRIE) of rotors in micro-wind turbines based on micro-electro-mechanical systems (MEMS) technology. The surface profile of an MEMS rotor can be controlled by modifying the scallop size of the DRIE surface through changing the process recipe. The fabrication of a planar disk-type MEMS rotor through the MEMS fabrication process was carried out, and for the comparison of the improvements in the performance of each rotor, RPM testing and open circuit output voltage experiments of stators and permanent magnets were performed. We found that the smooth etching profile with a minimized scallop size formed using DRIE results in improved rotation properties in MEMS-based wind turbine rotors.

4.
Tissue Eng Regen Med ; 18(4): 561-571, 2021 08.
Article in English | MEDLINE | ID: mdl-34313971

ABSTRACT

BACKGROUND: Extracellular vesicles (EVs) derived from plants have emerged as potential candidates for cosmetic and therapeutic applications. In this study, we isolated EVs from Aloe vera peels (A-EVs) and investigated the antioxidant and wound healing potential of A-EVs. METHODS: A-EVs were isolated by ultracentrifugation and tangential flow filtration and were characterized using transmission electron microscopy, nanoparticle tracking analysis. The cytotoxicity and cellular uptake of A-EVs were investigated by WST-1 assay and flow cytometry. The antioxidant effect of A-EVs was evaluated by superoxide dismutase (SOD) activity assay and cellular antioxidant activity (CAA) assay. The wound healing potential was assessed by in vitro scratch assay using human keratinocytes (HaCaT) and fibroblasts (HDF). The expression of nuclear factor erythroid 2-related factor 2 (Nrf2) and their associated genes was analyzed by quantitative RT-PCR. RESULTS: A-EVs displayed a round shape and had diameters from 50 to 200 nm. A-EVs showed good cytocompatibility on human skin cells and were internalized into HaCaT cells via clathrin-, caveolae-mediated endocytosis, and membrane fusion. The SOD activity and CAA assays exhibited that A-EVs had antioxidant activity and reduced intracellular ROS levels in H2O2-treated HaCaT cells in a dose-dependent manner. A scratch assay showed that A-EVs enhanced the migration ability of HaCaT and HDF. Moreover, A-EVs significantly upregulated the mRNA expression of Nrf2, HO-1, CAT, and SOD genes in H2O2-treated HaCaT cells. Our findings reveal that A-EVs could activate the antioxidant defense mechanisms and wound healing process via the Nrf2 activation. CONCLUSION: Overall results suggest that the A-EVs are promising as a potential agent for skin regeneration.


Subject(s)
Aloe , Extracellular Vesicles , Antioxidants/pharmacology , Hydrogen Peroxide , Wound Healing
5.
J Control Release ; 336: 285-295, 2021 08 10.
Article in English | MEDLINE | ID: mdl-34174353

ABSTRACT

Allogeneic transplantation of mesenchymal stem cell-derived extracellular vesicles (EVs) offers great potential for treating liver fibrosis. However, owing to their intrinsic surface characteristics, bare EVs are non-specifically distributed in the liver tissue after systemic administration, leading to limited therapeutic efficacy. To target activated hepatic stellate cells (HSCs), which are responsible for hepatic fibrogenesis, vitamin A-coupled small EVs (V-EVs) were prepared by incorporating vitamin A derivative into the membrane of bare EVs. No significant differences were found in the particle size and morphology between bare and V-EVs. In addition, surface engineering of EVs did not affect the expression of surface marker proteins (e.g., CD63 and CD9), as demonstrated by flow cytometry. Owing to the surface incorporation of vitamin A, V-EVs were selectively taken up by activated HSCs via receptor-mediated endocytosis. When systemically administered to mice with liver fibrosis, V-EVs effectively targeted activated HSCs in the liver tissue, resulting in reversal of the fibrotic cascade. Consequently, even at a 10-fold lower dose, V-EVs exhibited comparable anti-fibrotic effects to those of bare EVs, substantiating their therapeutic potential for liver fibrosis.


Subject(s)
Extracellular Vesicles , Mesenchymal Stem Cells , Animals , Hepatic Stellate Cells , Liver Cirrhosis/drug therapy , Mice , Vitamin A
6.
Sci Rep ; 10(1): 16339, 2020 10 01.
Article in English | MEDLINE | ID: mdl-33004904

ABSTRACT

Poly(L-lactic acid) (PLLA) based piezoelectric polymers are gradually becoming the substitute for the conventional piezoelectric ceramic and polymeric materials due to their low cost and biodegradable, non-toxic, piezoelectric and non-pyroelectric nature. To improve the piezoelectric properties of melt-spun poly(L-lactic acid) (PLLA)/BaTiO3, we optimized the post-processing conditions to increase the proportion of the ß crystalline phase. The α → ß phase transition behaviour was determined by two-dimensional wide-angle x-ray diffraction and differential scanning calorimetry. The piezoelectric properties of PLLA/BaTiO3 fibres were characterised in their yarn and textile form through a tapping method. From these results, we confirmed that the crystalline phase transition of PLLA/BaTiO3 fibres was significantly enhanced under the optimised post-processing conditions at a draw ratio of 3 and temperature of 120 °C during the melt-spinning process. The results indicated that PLLA/BaTiO3 fibres could be a one of the material for organic-based piezoelectric sensors for application in textile-based wearable piezoelectric devices.

7.
Environ Sci Technol ; 53(23): 14041-14053, 2019 Dec 03.
Article in English | MEDLINE | ID: mdl-31602972

ABSTRACT

Hydrogen production from renewable resources, such as lignocellulosic biomass, is highly desired, under the most sustainable and mildest reaction conditions. In this study, a new sustainable three-step process for the production of hydrogen has been proposed. In the first step, a crude formic acid (CF) solution, which included typical reaction byproducts, in particular, acetic acid, levulinic acid, saccharides, 5-hydroxymethylfurfural, furfural, and lignin, was obtained through the combined hydrolysis/oxidation of the biomass, in the presence of diluted sulfuric acid/hydrogen peroxide, as homogeneous catalysts. In the second one, the distilled formic acid (DF) solution was obtained by distillation of the CF solution, for example, by isolating liquid byproducts, or the lignin-free CF (LCF) solution was recovered by CF filtration for the elimination of only solid lignin particles. In the final step, hydrogen was produced from the DF or LCF solutions through formic acid dehydrogenation over Pd supported on amine-functionalized mesoporous silica catalysts, in the presence of sodium formate, as an additive. The clean hydrogen, which is produced from biomass passing through formic acid, could be applied as an energy source of fuel cells. This new hydrogen production process is smart, allowing the hydrogen production with mild reaction conditions, eventually starting from different lignocellulosic feedstocks, and it could be integrated within the existing hydrothermal technology for levulinic acid production, which has been already recognized as efficient and sustainable. In addition to the production of hydrogen as an energy source of fuel cells, formic acid derived from biomass could be utilized as a platform chemical for chemical, agricultural, textile, leather, pharmaceutical, and rubber industries.


Subject(s)
Formates , Lignin , Biomass , Hydrogen , Hydrolysis , Temperature
8.
Aesthet Surg J ; 38(2): 192-198, 2018 Feb 17.
Article in English | MEDLINE | ID: mdl-29117291

ABSTRACT

BACKGROUND: Botulinum toxin (BoNT) is widely used to treat masseter muscle hypertrophy. Changes in the muscle thickness have been found in many studies, but there has been no report on changes in the thickness from the skin surface to the masseter muscle. OBJECTIVES: We aimed to use ultrasonography to measure not only changes in the muscle thickness but also changes in subcutaneous thickness. METHODS: This study enrolled 20 volunteer patients: 10 were assigned to an experimental group (injected with each side 25 U of botulinum toxin into both masseter muscles) and 10 to a control group (injected with normal saline). The thicknesses were measured before the injection and at 4, 8, and 12 weeks after the injection both at rest and during maximum muscle contraction. RESULTS: The subcutaneous thickness did not differ significantly over time either at rest (P = 0.063) or during maximal contraction (P = 0.392), or between the experimental and control groups at rest (P = 0.392) or during maximum contraction (P = 0.259). The muscle thickness in the experimental group differed significantly over time. CONCLUSIONS: Botulinum toxin injection only changes the muscle thickness and does not affect the subcutaneous thickness from the skin surface to the masseter muscle.


Subject(s)
Botulinum Toxins, Type A/administration & dosage , Hypertrophy/drug therapy , Masseter Muscle/abnormalities , Neuromuscular Agents/administration & dosage , Subcutaneous Tissue/drug effects , Adult , Botulinum Toxins, Type A/adverse effects , Female , Humans , Hypertrophy/pathology , Injections, Intramuscular/adverse effects , Male , Masseter Muscle/diagnostic imaging , Masseter Muscle/drug effects , Masseter Muscle/pathology , Neuromuscular Agents/adverse effects , Sex Factors , Subcutaneous Tissue/anatomy & histology , Subcutaneous Tissue/diagnostic imaging , Ultrasonography , Young Adult
9.
Colloids Surf B Biointerfaces ; 149: 122-129, 2017 Jan 01.
Article in English | MEDLINE | ID: mdl-27744209

ABSTRACT

Self-assembled nanoparticles based on PEGylated human α-elastin were prepared as a potential vehicle for sustained protein delivery. The α-elastin was extracted from human adipose tissue and modified with methoxypolyethyleneglycol (mPEG) to control particle size and enhance the colloidal stability. The PEGylated human α-elastin showed sol-to-particle transition with a lower critical solution temperature (LCST) of 25°C-40°C in aqueous media. The PEGylated human α-elastin nanoparticles (PhENPs) showed a narrow size distribution with an average diameter of 330±33nm and were able to encapsulate significant amounts of insulin and bovine serum albumin (BSA) upon simple mixing at low temperature in water and subsequent heating to physiological temperature. The release profiles of insulin and BSA showed sustained release for 72h. Overall, the thermo-responsive self-assembled PhENPs provide a useful tool for a range of protein delivery and tissue engineering applications.


Subject(s)
Drug Carriers , Elastin/chemistry , Nanoparticles/chemistry , Polyethylene Glycols/chemistry , Adipose Tissue/chemistry , Animals , Cattle , Drug Compounding , Drug Liberation , Elastin/isolation & purification , Humans , Insulin/chemistry , Kinetics , Nanoparticles/ultrastructure , Particle Size , Phase Transition , Serum Albumin, Bovine/chemistry , Solutions , Temperature
10.
Biomacromolecules ; 17(1): 4-11, 2016 Jan 11.
Article in English | MEDLINE | ID: mdl-26607961

ABSTRACT

Extracellular matrix (ECM) provides structural support and biochemical cues for tissue development and regeneration. Here we report a thermosensitive hydrogel composed of soluble ECM (sECM) and methylcellulose (MC) for injectable stem cell delivery. The sECM was prepared by denaturing solid ECM extracted from human adipose tissue and then blended with a MC solution. At low temperatures, the sECM-MC solution displayed a viscous solution state in which the loss modulus (G″) was predominant over the storage modulus (G'). With increasing temperature, G' increased dramatically and eventually exceeded G″ around 34 °C, characteristic of the transition from a liquid-like state to an elastic gel-like state. After a single injection of the stem cell-embedded hydrogel in full thickness cutaneous wound, the wound healed rapidly through re-epithelialization and neovascularization with minimum scar formation. The overall results suggest that in-situ-forming sECM-MC hydrogels are a promising injectable vehicle for stem cell delivery and tissue regeneration.


Subject(s)
Extracellular Matrix/chemistry , Hydrogels/chemistry , Hydrogels/pharmacology , Methylcellulose/chemistry , Skin/drug effects , Stem Cells/drug effects , Wounds and Injuries/drug therapy , Cells, Cultured , Humans , Injections/methods , Regeneration/drug effects , Temperature
11.
J Control Release ; 222: 107-15, 2016 Jan 28.
Article in English | MEDLINE | ID: mdl-26699421

ABSTRACT

Exosomes released from skeletal muscle cells play important roles in myogenesis and muscle development via the transfer of specific signal molecules. In this study, we investigated whether exosomes secreted during myotube differentiation from human skeletal myoblasts (HSkM) could induce a cellular response from human adipose-derived stem cells (HASCs) and enhance muscle regeneration in a muscle laceration mouse model. The exosomes contained various signal molecules including myogenic growth factors related to muscle development, such as insulin-like growth factors (IGFs), hepatocyte growth factor (HGF), fibroblast growth factor-2 (FGF2), and platelet-derived growth factor-AA (PDGF-AA). Interestingly, exosome-treated HASCs fused with neighboring cells at early time points and exhibited a myotube-like phenotype with increased expression of myogenic proteins (myosin heavy chain and desmin). On day 21, mRNAs of terminal myogenic genes were also up-regulated in exosome-treated HASCs. Moreover, in vivo studies demonstrated that exosomes from differentiating HSkM reduced the fibrotic area and increased the number of regenerated myofibers in the injury site, resulting in significant improvement of skeletal muscle regeneration. Our findings suggest that exosomes act as a biochemical cue directing stem cell differentiation and provide a cell-free therapeutic approach for muscle regeneration.


Subject(s)
Exosomes/physiology , Muscle Development/physiology , Muscle, Skeletal/cytology , Muscle, Skeletal/physiology , Stem Cells/cytology , Adipose Tissue/cytology , Animals , Cell Proliferation/drug effects , Cells, Cultured , Female , Humans , Intercellular Signaling Peptides and Proteins/pharmacology , Male , Mice, Nude , Muscle, Skeletal/injuries , Regeneration/physiology
12.
J Biomater Sci Polym Ed ; 26(13): 841-54, 2015.
Article in English | MEDLINE | ID: mdl-26096447

ABSTRACT

We designed bilayer composites composed of an upper layer of titanium dioxide (TiO2)-incorporated chitosan membrane and a sub-layer of human adipose-derived extracellular matrix (ECM) sheet as a wound dressing for full-thickness wound healing. The dense and fibrous top layer, which aims to protect the wound from bacterial infection, was prepared by electrospinning of chitosan solution followed by immersion in TiO2 solution. The sponge-like sub-layer, which aims to promote new tissue regeneration, was prepared with acellular ECM derived from human adipose tissue. Using a modified drop plate method, there was a 33.9 and 69.6% reduction in viable Escherichia coli and Staphylococcus aureus on the bilayer composite, respectively. In an in vivo experiment using rats, the bilayer composites exhibited good biocompatibility and provided proper physicochemical and compositional cues at the wound site. Changes in wound size and histological examination of full-thickness wounds showed that the bilayer composites induced faster regeneration of granulation tissue and epidermis with less scar formation, than control wounds. Overall results suggest that the TiO2-incorporated chitosan/ECM bilayer composite can be a suitable candidate as a wound dressing, with an excellent inhibition of bacterial penetration and wound healing acceleration effects.


Subject(s)
Bandages , Chitosan , Titanium , Adipose Tissue/metabolism , Animals , Bandages/microbiology , Disease Models, Animal , Escherichia coli , Extracellular Matrix/metabolism , Female , Fluorescent Antibody Technique , Humans , Microscopy, Electron, Scanning , Rats, Sprague-Dawley , Skin/injuries , Skin/pathology , Staphylococcus aureus , Wound Healing
13.
J Control Release ; 193: 42-50, 2014 Nov 10.
Article in English | MEDLINE | ID: mdl-24979211

ABSTRACT

Since stem cells have the capacity to differentiate into a variety of cell types, stem cell delivery systems (SCDSs) can be effective therapeutic strategies for a multitude of diseases and disorders. For stem cell-based therapy, stem cells are introduced directly (or peripherally) into a target tissue via different delivery systems. Despite initial promising results obtained from preclinical studies, a number of technical hurdles must be overcome for ultimate clinical utility of stem cells. A key aspect of SCDSs is how to create local environments, called stem cell niches, for improvement of survival and engraftment as well as the fate of transplanted stem cells. The stem cell niches encompassing a wide range of biochemical, biophysical, and biomechanical cues play a guidance role to modulate stem cell behaviors such as adhesion, proliferation, and differentiation. Recent studies have tried to decipher the complex interplay between stem cells and niches, and thereafter to engineer SCDS, mimicking dynamic stem cell niches encompassing a wide range of biochemical, biophysical, and biomechanical cues. Here, we discuss the biological role of stem cell niches and highlight recent progress in SCDS to mimic stem cell niches, particularly focusing on important biomaterial properties for modulating stem cell fate.


Subject(s)
Biomimetic Materials/chemistry , Extracellular Matrix/chemistry , Guided Tissue Regeneration/methods , Stem Cell Niche , Stem Cell Transplantation/methods , Stem Cells/cytology , Animals , Biomechanical Phenomena , Cell Differentiation , Cell Movement , Cell Proliferation , Elasticity , Porosity , Protein Binding , Receptors, Cell Surface/metabolism , Stem Cell Niche/physiology , Stem Cells/metabolism , Stress, Mechanical , Surface Properties
14.
Nanoscale ; 6(7): 3483-7, 2014 Apr 07.
Article in English | MEDLINE | ID: mdl-24384786

ABSTRACT

Mesoporous silica and titania supraparticles with controllable pore size, particle size, and macroscopic morphology were readily synthesized by a novel synthetic pathway using meniscus templating on a superhydrophobic surface, which is much simpler than well-known emulsion systems. Moreover, we first report that despite the very large radius of droplet curvature on a millimeter scale, supraparticles kept the round cap morphology due to addition of sucrose as a shape preserver as well as a pore-forming agent. In addition, mesoporous silica and titania supraparticles provided good adsorption performance for Acid Blue 25 and Cr(VI), and were easily separated from the solution by using a scoop net after adsorption tests.


Subject(s)
Silicon Dioxide/chemistry , Titanium/chemistry , Adsorption , Anthraquinones/chemistry , Chromium/chemistry , Hydrophobic and Hydrophilic Interactions , Nanostructures/chemistry , Porosity , Surface Properties
15.
Environ Sci Technol ; 47(3): 1704-10, 2013 Feb 05.
Article in English | MEDLINE | ID: mdl-23286316

ABSTRACT

Coal-fired power plants are facing to two major independent problems, namely, the burden to reduce CO(2) emission to comply with renewable portfolio standard (RPS) and cap-and-trade system, and the need to use low-rank coal due to the instability of high-rank coal supply. To address such unresolved issues, integrated gasification combined cycle (IGCC) with carbon capture and storage (CCS) has been suggested, and low rank coal has been upgraded by high-pressure and high-temperature processes. However, IGCC incurs huge construction costs, and the coal upgrading processes require fossil-fuel-derived additives and harsh operation condition. Here, we first show a hybrid coal that can solve these two problems simultaneously while using existing power plants. Hybrid coal is defined as a two-in-one fuel combining low rank coal with a sugar cane-derived bioliquid, such as molasses and sugar cane juice, by bioliquid diffusion into coal intrapores and precarbonization of the bioliquid. Unlike the simple blend of biomass and coal showing dual combustion behavior, hybrid coal provided a single coal combustion pattern. If hybrid coal (biomass/coal ratio = 28 wt %) is used as a fuel for 500 MW power generation, the net CO(2) emission is 21.2-33.1% and 12.5-25.7% lower than those for low rank coal and designed coal, and the required coal supply can be reduced by 33% compared with low rank coal. Considering high oil prices and time required before a stable renewable energy supply can be established, hybrid coal could be recognized as an innovative low-carbon-emission energy technology that can bridge the gulf between fossil fuels and renewable energy, because various water-soluble biomass could be used as an additive for hybrid coal through proper modification of preparation conditions.


Subject(s)
Carbon Dioxide/analysis , Coal/analysis , Power Plants , Saccharum/chemistry , Adsorption , Computer Simulation , Differential Thermal Analysis , Hydrophobic and Hydrophilic Interactions , Molasses , Nitrogen/chemistry , Porosity , Temperature
16.
Tissue Eng Part C Methods ; 18(11): 866-76, 2012 Nov.
Article in English | MEDLINE | ID: mdl-22559904

ABSTRACT

Cells in tissues are surrounded by the extracellular matrix (ECM), a gel-like material of proteins and polysaccharides that are synthesized and secreted by cells. Here we propose that the ECM can be isolated from porcine adipose tissue and holds great promise as a xenogeneic biomaterial for tissue engineering and regenerative medicine. Porcine adipose tissue is easily obtained in large quantities from commonly discarded food waste. Decellularization protocols have been developed for extracting an intact ECM while effectively eliminating xenogeneic epitopes and minimally disrupting the ECM composition. Porcine adipose tissue was defatted by homogenization and centrifugation. It was then decellularized via chemical (1.5 M sodium chloride and 0.5% sodium dodecyl sulfate) and enzymatic treatments (DNase and RNase) with temperature control. After decellularization, immunogenic components such as nucleic acids and α-Gal were significantly reduced. However, abundant ECM components, such as collagen (332.9±12.1 µg/mg ECM dry weight), sulfated glycosaminoglycan (GAG, 85±0.7 µg/mg ECM dry weight), and elastin (152.6±4.5 µg/mg ECM dry weight), were well preserved in the decellularized material. The biochemical and mechanical features of a decellularized ECM supported the adhesion and growth of human cells in vitro. Moreover, the decellularized ECM exhibited biocompatibility, long-term stability, and bioinductivity in vivo. The overall results suggest that the decellularized ECM derived from porcine adipose tissue could be useful as an alternative biomaterial for xenograft tissue engineering.


Subject(s)
Adipose Tissue/metabolism , Biocompatible Materials/pharmacology , Extracellular Matrix/chemistry , Tissue Engineering/methods , Adipogenesis/drug effects , Adipogenesis/genetics , Adipose Tissue/cytology , Adipose Tissue/ultrastructure , Animals , Extracellular Matrix/ultrastructure , Female , Fluorescent Antibody Technique , Humans , Materials Testing , Mice , Mice, Inbred ICR , Sus scrofa , Tissue Scaffolds
17.
Biotechnol Prog ; 28(4): 973-80, 2012 Jul.
Article in English | MEDLINE | ID: mdl-22549937

ABSTRACT

Collagen, the most abundant protein in vertebrates, is a useful biomaterial in pharmaceutical and medical industries. So far, most collagen has been extracted from animals and cadavers. Herein, we suggest human adipose tissue, which is routinely abandoned after liposuction, as a plentiful source of human collagen. In this study, human collagen was obtained from adipose tissue through two successive major steps: (i) extraction of the extracellular matrix (ECM) by pulverization, centrifugation, alkaline, and alcohol treatment; (ii) isolation of collagen from ECM by pepsin treatment in dilute acetic acid. The purified human adipose-derived collagen was characterized by Fourier transform infrared spectroscopy, polyacrylamide gel electrophoresis, amino acid analysis, and circular dichroism spectroscopy. The extracted collagen showed a typical triple helix structure, good thermal stability due to abundant imino acids, and high solubility at acidic pH. The collagen greatly facilitated the adhesion and proliferation of human adipose-derived stem cells and normal human dermal fibroblasts on polystyrene plates. These results suggest that human adipose tissue obtained by liposuction can provide human collagen for use in cosmetics, pharmaceutics, and medicine.


Subject(s)
Adipose Tissue/chemistry , Collagen/isolation & purification , Adult , Animals , Cattle , Cells, Cultured , Collagen/chemistry , Female , Humans , Peptide Mapping , Rats , Spectroscopy, Fourier Transform Infrared , Young Adult
18.
Cell Tissue Res ; 348(3): 559-67, 2012 Jun.
Article in English | MEDLINE | ID: mdl-22447167

ABSTRACT

Decellularized human extracellular matrices (ECMs) are an extremely appealing biomaterial for tissue engineering and regenerative medicine. In this study, we decellularized human adipose tissue, fabricated a thin ECM sheet and explored the potential of this human adipose-derived ECM sheet as a substrate to support the formation of tissues other than adipose tissue. Acellular ECM sheets were fabricated from human adipose tissue through successive physical and chemical treatments: homogenization, centrifugation, casting, freeze-drying and sodium dodecyl sulfate treatment. The ECM sheets exhibited good mechanical properties, despite their porous structure. They degraded quickly in the presence of collagenase and the degradation rate increased with the collagenase concentration in phosphate-buffered saline. Five different human cell types, covering a broad range of cells and applications (normal human dermal fibroblasts, human aortic smooth muscle cells, human chondrocytes, human umbilical vein endothelial cells and human adipose-derived stem cells), were seeded onto the ECM sheets. All the human cell types spread well, proliferated and were successfully integrated into the decellularized ECM sheet. Overall, the results suggest that recellularized ECM sheets are a promising substitute for defective or damaged human tissues.


Subject(s)
Adipose Tissue/cytology , Extracellular Matrix/metabolism , Tissue Engineering/methods , Adult , Aorta/cytology , Cell Proliferation/drug effects , Cells, Cultured , Chondrocytes/cytology , Chondrocytes/drug effects , Dermis/cytology , Extracellular Matrix/ultrastructure , Female , Fibroblasts/cytology , Fibroblasts/drug effects , Human Umbilical Vein Endothelial Cells/cytology , Human Umbilical Vein Endothelial Cells/drug effects , Humans , Indoles/metabolism , Microscopy, Fluorescence , Myocytes, Smooth Muscle/cytology , Myocytes, Smooth Muscle/drug effects , Porosity/drug effects , Sodium Dodecyl Sulfate/pharmacology , Staining and Labeling , Stem Cells/cytology , Stem Cells/drug effects , Stress, Mechanical , Tensile Strength/drug effects , Young Adult
19.
Int J Pharm ; 427(2): 305-10, 2012 May 10.
Article in English | MEDLINE | ID: mdl-22366486

ABSTRACT

Carrier geometry is a key parameter of drug delivery systems and has significant impact on the drug release rate and interaction with cells and tissues. Here we present a piezoelectric inkjet printing system as a simple and convenient approach for fabrication of drug-loaded polymer microparticles with well-defined and controlled shapes. The physical properties of paclitaxel (PTX)-loaded poly(lactic-co-glycolic acid) (PLGA) inks, such as volatility, viscosity and surface tension, were optimized for piezoelectric inkjet printing, and PTX-loaded PLGA microparticles were fabricated with various geometries, such as circles, grids, honeycombs, and rings. The resulting microparticles with 10% (w/w) PTX exhibited a fairly homogeneous shape and size. The microparticle fabrication by piezoelectric inkjet printing was precise, reproducible, and highly favorable for mass production. The microparticles exhibited a biphasic release profile with an initial burst due to diffusion and a subsequent, slow second phase due to degradation of PLGA. The release rate was dependent on the geometry, mainly the surface area, with a descending rate order of honeycomb>grid, ring>circle. The PTX-loaded microparticles showed a comparable activity in inhibiting the growth of HeLa cells. Our results demonstrate that a piezoelectric inkjet printing system would provide a new approach for large-scale manufacturing of drug carriers with a desired geometry.


Subject(s)
Drug Delivery Systems , Nanoparticles , Antineoplastic Agents, Phytogenic/administration & dosage , Chemistry, Pharmaceutical , Chromatography, High Pressure Liquid , Colorimetry , Excipients , HeLa Cells , Humans , Ink , Kinetics , Lactic Acid , Microscopy, Electron, Scanning , Paclitaxel/administration & dosage , Particle Size , Polyglycolic Acid , Polylactic Acid-Polyglycolic Acid Copolymer , Solubility , Spectrophotometry, Ultraviolet , Tetrazolium Salts , Viscosity
20.
Tissue Eng Part A ; 18(1-2): 80-92, 2012 Jan.
Article in English | MEDLINE | ID: mdl-21905881

ABSTRACT

Extracellular matrix (ECM) secreted from the resident cell of tissue is an ideal biomaterial evolved by nature. Cartilage is also built from well-organized ECM components in a gel-like structure with a high collagen and proteoglycan content. Here, we explored cartilage tissue engineering using ECM scaffolds seeded with stem cells. Both scaffolds and stem cells were isolated from human adipose tissue, which is abundant and easily harvested in the human body. The human ECM scaffolds contained various endogenous bioactive factors, including transforming growth factor-beta1 (TGF-ß1, 8782±4989 pg/g, dry ECM), insulin growth factor-1 (13319±1388 pg/g, dry ECM), basic fibroblast growth factor (82373±9572 pg/g, dry ECM), and vascular endothelial growth factor (25647±2749 pg/g, dry ECM). A composite of ECM and stem cells was prepared and cultured in chondrogenic medium (with 10 ng/mL TGF-ß1 or not) for 45 days. The volumes and weights of the composites increased during culture and the surface gradually became smooth. Cell viability remained high throughout the 45 days of in vitro culture. Composites showed the formation of cartilage-like tissue with the synthesis of cartilage-specific proteins such as collagen and glycosaminoglycan. Important chondrogenic markers were expressed including Sox-9, aggrecan, and collagen type II and XI. These results demonstrate that a cell/ECM composite containing endogenous bioactive factors could provide biochemical cues for the promotion of cartilage formation.


Subject(s)
Adipose Tissue/cytology , Cartilage/physiology , Extracellular Matrix/metabolism , Stem Cells/cytology , Tissue Engineering/methods , Tissue Scaffolds/chemistry , Adult , Biomarkers/metabolism , Cells, Cultured , Chondrogenesis/genetics , Collagen/metabolism , DNA/metabolism , Female , Flow Cytometry , Fluorescent Antibody Technique , Gels , Gene Expression Regulation , Glycosaminoglycans/metabolism , Humans , Intercellular Signaling Peptides and Proteins/metabolism , Microscopy, Electron, Scanning , Microscopy, Fluorescence , Stem Cells/metabolism , Stem Cells/ultrastructure , Young Adult
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