Human embryonic stem cells cultured on hydrogels grafted with extracellular matrix protein-derived peptides with polyethylene glycol joint nanosegments.

Human pluripotent stem cells (hPSCs) can be proliferated on completely synthetic materials under xeno-free cultivation conditions using biomaterials grafted with extracellular matrix protein (ECM)-derived peptides. However, cell culture biomaterials grafted with ECM-derived peptides must be prepared using a high concentration of peptide reaction solution (e.g. 1000 µg/ml), whereas the ECM concentration of the ECM-coated surface for hPSC culture is typically 5 µg/ml. We designed a polyethylene glycol (PEG) joint nanosegment (linker) to be used between base cell culture biomaterials and bioactive ECM-derived peptides to enhance the probability of contact between ECM-derived peptides and cell binding receptors of hPSCs. Vitronectin-derived peptides with glycine joint nanosegments (GCGG) were conjugated onto poly (vinyl alcohol-co-itaconic acid) hydrogels via PEG joint nanosegments, and human embryonic stem cells (hESCs) were cultivated on these hydrogels. hESCs could successfully be cultivated on hydrogels while maintaining their pluripotency and differentiation potential to differentiate into cells that are induced from three germ layers in vitro and in vivo, where only a 50 µg/ml ECM-derived peptide concentration was used when the PEG joint nanosegments were introduced into peptides that were grafted onto hydrogel surfaces. The joint nanosegments between bioactive peptides and base cell culture biomaterials were found to contribute to efficient hESC attachment and proliferation.

Thermoresponsive surfaces designed for the proliferation and differentiation of human pluripotent stem cells.

Thermoresponsive surfaces enable the detachment of cells or cell sheets by decreasing the temperature of the surface when harvesting the cells. However, human pluripotent stem cells (hPSCs), such as embryonic stem cells and induced pluripotent stem cells, cannot be directly cultured on a thermoresponsive surface; hPSCs need a specific extracellular matrix to bind to the integrin receptors on their surfaces. We prepared a thermoresponsive surface by using poly(N-isopropylacrylamide-co-butylacrylate) and recombinant vitronectin to provide an optimal coating concentration for the hPSC culture. hPSCs can be cultured on the same thermoresponsive surface for 5 passages by partial detachment of the cells from the surface by decreasing the temperature for 30 min; then, the remaining hPSCs were subsequently cultured on the same dishes following the addition of new cultivation media. The detached cells, even after continual culture for five passages, showed high pluripotency, the ability to differentiate into cells derived from the 3 germ layers and the ability to undergo cardiac differentiation.

Xeno-free and feeder-free culture and differentiation of human embryonic stem cells on recombinant vitronectin-grafted hydrogels.

Recombinant vitronectin-grafted hydrogels were developed by adjusting surface charge of the hydrogels with grafting of poly-l-lysine for optimal culture of human embryonic stem cells (hESCs) under xeno- and feeder-free culture conditions, with elasticity regulated by crosslinking time (10-30 kPa), in contrast to conventional recombinant vitronectin coating dishes, which have a fixed stiff surface (3 GPa). hESCs proliferated on the hydrogels for over 10 passages and differentiated into the cells derived from three germ layers indicating the maintenance of pluripotency. hESCs on the hydrogels differentiated into cardiomyocytes under xeno-free culture conditions with much higher efficiency (80% of cTnT+ cells) than those on conventional recombinant vitronectin or Matrigel-coating dishes just only after 12 days of induction. It is important to have an optimal design of cell culture biomaterials where biological cues (recombinant vitronectin) and physical cues (optimal elasticity) are combined for high differentiation of hESCs into specific cell lineages, such as cardiomyocytes, under xeno-free and feeder-free culture conditions.

Development of biotin molecule targeted cancer cell drug delivery of doxorubicin loaded κ-carrageenan grafted graphene oxide nanocarrier.

Cervical cancer is one of the most occurring cancers and the fourth leading occurrence of cancer in women, worldwide. In this study, we planned to synthesis κ-Carrageenan grafted graphene oxide nanocarrier conjugated with biotin (GO-κ-Car-biotin) for targeted cervical cancer. Doxorubicin (DOX) is a well-known anticancer drug for any type of cancer and it is used to entrap over on the graphene oxide surface via π-π stacking interaction. The chemical function and crystalline nature of the synthesized nanocarrier was characterized by Fourier Transformed Infrared Spectroscopy (FT-IR) and X-ray diffraction Analysis (XRD). The surface morphological study was carried out through Scanning Electron Microscopy (SEM), Transmission electron microscopy (TEM) and Atomic force microscopy (AFM). The in-vitro drug release profile of DOX was carried out by UV-Vis spectrometer at the λmax value of 480 nm. The entrapment of DOX on GO-κ-car-biotin has been observed at 94%. The hydrophilic DOX drug has excellent pH-sensitive drug released in an in-vitro study. The anticancer efficiency of the synthesized GO-based nanocarrier was examined using HeLa cell line in-vitro. Cell viability, proliferation, cytotoxicity, and nuclear chromatin condensation was studied by trypan blue assay, triphosphate assay (ATP), lactate dehydrogenase assay (LDH) and Hoechst staining respectively. Finally, biotin leading GO-κ-Car carrier demonstrated is a promising drug delivery system for cervical cancer treatment.

Mucoadhesive guargum hydrogel inter-connected chitosan-g-polycaprolactone micelles for rifampicin delivery.

Natural polymer guar gum has one of the highest viscosities in water solution and hence, these are significantly used in pharmaceutical applications. Guar gum inter-connected micelles as a new carrier has been developed for poor water soluble rifampicin drug. The hydrogel inter-connected micelle core was formulated as a hydrophilic inner and hydrophobic outer core by using guar gum/chitosan/polycaprolactone and the carrier interaction with rifampicin was confirmed by FT-IR. The morphological observations were carried out through TEM, SEM and AFM analysis. The encapsulation efficiency and in-vitro drug release behavior of prepared hydrogel based micelle system was analyzed by UV-vis spectrometry. The anti-bacterial activity against K. pneumoniae and S. aureus was studied by observing their ruptured surface by SEM. The cytotoxicity study reveals that the pure polymeric system has no toxic effect whereas drug loaded ones showed superior activity against THP-1 cells. From the cell apoptosis analyses, the apoptosis was carried out in a time dependent manner. The cell uptake behavior was also observed in THP-1 cells which indicate that the hydrogel based micelle system is an excellent material for the mucoadhesive on intracellular alveolar macrophage treatment.

Modulatory and regenerative potential of transplanted bone marrow-derived mesenchymal stem cells on rifampicin-induced kidney toxicity.

INTRODUCTION: Anti-tuberculosis agent rifampicin is extensively used for its effectiveness. Possible complications of tuberculosis and prolonged rifampicin treatment include kidney damage; these conditions can lead to reduced efficiency of the affected kidney and consequently to other diseases. Bone marrow-derived mesenchymal stem cells (BMMSCs) can be used in conjunction with rifampicin to avert kidney damage; because of its regenerative and differentiating potentials into kidney cells. This research was designed to assess the modulatory and regenerative potentials of MSCs in averting kidney damage due to rifampicin-induced kidney toxicity in Wistar rats and their progenies. BMMSCs used in this research were characterized according to the guidelines of International Society for Cellular Therapy. METHODS: The rats (male and female) were divided into three experimental groups, as follows: Group 1: control rats (4 males & 4 females); Group 2: rats treated with rifampicin only (4 males & 4 females); and Group 3: rats treated with rifampicin plus MSCs (4 males & 4 females). Therapeutic doses of rifampicin (9 mg/kg/day for 3-months) and MSCs infusions (twice/month for 3-months) were administered orally and intravenously respectively. At the end of the three months, the animals were bred together to determine if the effects would carry over to the next generation. Following breeding, the rats were sacrificed to harvest serum for biochemical analysis and the kidneys were also harvested for histological analysis and quantification of the glomeruli size, for the adult rats and their progenies. RESULTS: The results showed some level of alterations in the biochemical indicators and histopathological damage in the rats that received rifampicin treatment alone, while the control and stem cells treated group showed apparently normal to nearly normal levels of both bio-indicators and normal histological architecture. CONCLUSIONS: Intravenous administration of MSCs yielded sensible development, as seen from biochemical indicators, histology and the quantitative cell analysis, hence implying the modulatory and regenerative properties of MSCs.

Inositol-6 phosphate inhibits the mTOR pathway and induces autophagy-mediated death in HT-29 colon cancer cells.

INTRODUCTION: Colorectal cancer (CRC) is common, with a worldwide incidence estimated at more than 1 million cases annually. Therefore, the search for agents for CRC treatment is highly warranted. Inositol-6 phosphate (IP6) is enriched in rice bran and possesses many beneficial effects. In the present study the effect of IP6 on autophagy-mediated death by modulating the mTOR pathway in HT-29 colon cancer cells was studied. MATERIAL AND METHODS: Autophagy was assessed by acridine orange (AO) staining, transmission electron microscopy, and western blotting to detect LC3-II and Beclin 1. Akt/mTOR signaling protein expression was also analyzed by western blotting. Apoptosis was analyzed by annexin V staining. RESULTS: Incubation of cells with IP6 resulted in downregulation of the p-Akt at 3h. Along with that confocal microscopic analysis of p-AKT, IP6 administration resulted that a diminished expression of p-Akt. mTOR pathway regulates autophagy and incubation with IP6 to HT-29 cells showed decreased expression of p-70S6Kinase, 4-EBP-1 in a time-dependent manner. Inositol-6 phosphate (10 µg/ml, 24 and 48 h) induced autophagic vesicles, as confirmed by AO staining and transmission electron microscopy. We also found increased expression of LC3-II and Beclin 1 in a time-dependent manner after incubation with IP6. Furthermore, IP6 induced apoptosis, as revealed by annexin V staining. CONCLUSIONS: Our results clearly indicate that IP6 induces autophagy by inhibiting the Akt/mTOR pathway.

Osteoblast response to Vitamin D3 loaded cellulose enriched hydroxyapatite Mesoporous silica nanoparticles composite.

Composite materials hold cellulose(C) established network and biomimetic Hydroxyapatite (HAP) are potentially appropriate for bone formation and protect the external organisms. Tissue engineering scaffolds with unified porous and enhanced biological properties can be fabricated using a small quantity of porous additives. In this study we synthesizd a Cholecalciferol (VD3) loaded, cellulose functionalized hydroxyapatite nanocomposites with different concentration of Mesoporous silica nanoparticles (MSNs). VD3 plays an important role in the bone formation by regulating extracellular levels of calcium and phosphorus. FTIR, SEM, TEM, and X-ray diffraction techniques were used for the characterization of the prepared composites. VD3 releases from the VD3/C/HAP/MSN scaffold were observed by using UV-vis spectroscopy. The nanocomposites C/HAP/MSN, VD3/C/HAP/MSN showed higher viability compared with pure HAP and in-vitro studies revealed that the materials has enhanced the proliferative, adhesion, osteoinductive effects ALP activity and calcium deposition assay on osteoblasts like cells (MG63). Our outcome recommended that the 3D like VD3 loaded C/HAP/MSN nanocomposite scaffolds have a great potential as a bone tissue substitute.

Stimulus-responsive zinc oxide-functionalized macromolecular humic acid nanocarrier for enhancement of antibacterial activity of ciprofloxacin hydrochloride.

Macromolecular of naturally occurring humic acid (HA) have garnered interest in the chemical, biological and medicine industry owing to their unique behavior, i.e., strong adsorptive and non-toxic nature. Here, we investigated the functionalization of organic (HA) with inorganic (ZnO) hybrid nanoparticles for topical and site-targeted delivery of ciprofloxacin by simple emulsification techniques. Ciprofloxacin (CIPRO)-encapsulated hybrid nanocarrier constitute an attractive novel drug delivery vehicle for sustained release of antibiotics to bacterial infection sites in an extended and controlled manner. The analytical characteristics of the designed system were thoroughly investigated by FTIR, XRD, SEM/EDAX, and TEM. The drug release of ciprofloxacin over 24h was 87.5%, 98.03%, 97.44%, and 97.24% for pH2.5, 5.5, 6.8, and 8.0, respectively. The antibacterial activities results confirmed that the CIPRO-encapsulated hybrid nanocarrier showed excellent growth inhibition against microorganisms. This hybrid nanocarrier loaded with antibiotics represents a promising approach for targeted and controlled drug delivery to infected sites.

Human Pluripotent Stem Cell Culture on Polyvinyl Alcohol-Co-Itaconic Acid Hydrogels with Varying Stiffness Under Xeno-Free Conditions.

The effect of physical cues, such as the stiffness of biomaterials on the proliferation and differentiation of stem cells, has been investigated by several researchers. However, most of these investigators have used polyacrylamide hydrogels for stem cell culture in their studies. Therefore, their results are controversial because those results might originate from the specific characteristics of the polyacrylamide and not from the physical cue (stiffness) of the biomaterials. Here, we describe a protocol for preparing hydrogels, which are not based on polyacrylamide, where various stem, cells including human embryonic stem (ES) cells and human induced pluripotent stem (iPS) cells, can be cultured. Hydrogels with varying stiffness were prepared from bioinert polyvinyl alcohol-co-itaconic acid (P-IA), with stiffness controlled by crosslinking degree by changing crosslinking time. The P-IA hydrogels grafted with and without oligopeptides derived from extracellular matrix were investigated as a future platform for stem cell culture and differentiation. The culture and passage of amniotic fluid stem cells, adipose-derived stem cells, human ES cells, and human iPS cells is described in detail here. The oligopeptide P-IA hydrogels showed superior performances, which were induced by their stiffness properties. This protocol reports the synthesis of the biomaterial, their surface manipulation, along with controlling the stiffness properties and finally, their impact on stem cell fate using xeno-free culture conditions. Based on recent studies, such modified substrates can act as future platforms to support and direct the fate of various stem cells line to different linkages; and further, regenerate and restore the functions of the lost organ or tissue.

Deep Eutectic Solvent-Mediated FA-g-ß-Alanine-co-PCL Drug Carrier for Sustainable and Site-Specific Drug Delivery.

An amphiphilic polymer that consisted of a deep eutectic solvent (DES)-mediated drug carrier was designed, where the DES influenced the formation of folic acid (FA)-tagged g-ß-alanine-co-PCL polymer (DES@FA-g-ß-alanine-co-PCL); the nature of the carrier was investigated through emission analysis and pyrene used as a model probe (CMC = 0.4 mg/mL). The amphiphilic polymer was self-assembled into a sphere (≈204 nm diameter) with a surface charge of -3 ± 0.5 mV. The doxorubicin was incorporated and the structural changes were analyzed by UV-visible spectroscopy, FT-IR, XRD, Raman, and TGA analysis, while size and morphological analysis was performed by DLS, AFM, SEM, and TEM. The controlled release of drug from the carrier was observed at different pH levels. The enhanced anticancer potential of DOX-loaded polymeric micelle was studied both in vitro and in vivo breast cancer model. The treatment of DOX-loaded polymeric micelle reduces the viability and proliferation of MDA-MB-231 cells. From the results of the current investigation it concludes that the DOX-loaded polymeric micelle has enhance anticancer effect and it exhibits its potential effect at the dosage of 5 mg/kg body weight in mammary carcinoma-bearing rats. From the observed results, synthesized DOX-loaded polymeric micelle holds strong anticancer properties compared with free DOX and can be used as a potential carrier in the pharmaceutical industry.

From waste to high-value product: Jackfruit peel derived pectin/apatite bionanocomposites for bone healing applications.

Public requirements encouraged by the current asset framework drive industry to expand its general effectiveness by enhancing existing procedures or finding new uses for waste. Thus, the aim of this study was the isolation, fabrication, and characterization of pectin derived from jackfruit (Artocarpus heterophyllus) peels and the generation of hybrid of pectin (P)/apatite (HA) (P/HA) bionanocomposites. In this process, the natural pectin polymer derived from the peel of jackfruits was used in different concentrations for the fabrication of HA bionanocomposites. Characterization of the isolated pectin and bionanocomposites samples was performed with 1H NMR and 13C NMR, FTIR, XRD, SEM-EDX, and HR-TEM. Cytocompatibility, ALP, fibroblast stem cells, anti-inflammatory and cell adhesion testing of the fabricated bionanocomposites was showed good biocompatibility. Our results signify that the fabricated bionanocomposites might be applicable as bone graft materials.

Chemical Composition of Moringa oleifera Ethyl Acetate Fraction and Its Biological Activity in Diabetic Human Dermal Fibroblasts.

BACKGROUND: Moringa oleifera (MO), commonly known as the drumstick tree, is used in folklore medicine for the treatment of skin disease. OBJECTIVE: The objective of this study is to evaluate the ethyl acetate (EtOAc) fraction of MO leaves for in vitro antibacterial, antioxidant, and wound healing activities and conduct gas chromatography-mass spectrometry (GC-MS) analysis. MATERIALS AND METHODS: Antibacterial activity was evaluated against six Gram-positive bacteria and 10 Gram-negative bacteria by disc diffusion method. Free radical scavenging activity was assessed by 1, 1-diphenyl-2-picryl hydrazyl (DPPH) radical hydrogen peroxide scavenging and total phenolic content (TPC). Wound healing efficiency was studied using cell viability, proliferation, and scratch assays in diabetic human dermal fibroblast (HDF-D) cells. RESULTS: The EtOAc fraction showed moderate activity against all bacterial strains tested, and the maximum inhibition zone was observed against Streptococcus pyogenes (30 mm in diameter). The fraction showed higher sensitivity to Gram-positive strains than Gram-negative strains. In the quantitative analysis of antioxidant content, the EtOAc fraction was found to have a TPC of 65.81 ± 0.01. The DPPH scavenging activity and the hydrogen peroxide assay were correlated with the TPC value, with IC50 values of 18.21 ± 0.06 and 59.22 ± 0.04, respectively. The wound healing experiment revealed a significant enhancement of cell proliferation and migration of HDF-D cells. GC-MS analysis confirmed the presence of 17 bioactive constituents that may be the principal factors in the significant antibacterial, antioxidant, and wound healing activity. CONCLUSION: The EtOAc fraction of MO leaves possesses remarkable wound healing properties, which can be attributed to the antibacterial and antioxidant activities of the fraction. SUMMARY: Moringa oleifera (MO) leaf ethyl acetate (EtOAc) fraction possesses antibacterial activities toward Gram-positive bacteria such as Streptococcus pyogenes, Streptococcus faecalis, Bacillus subtilis, Bacillus cereus and Staphylococcus aureus, and Gram-negative bacteria such as Proteus mirabilis and Salmonella typhimuriumMO leaf EtOAc fraction contained the phenolic content of 65.81 ± 0.01 and flavonoid content of 37.1 ± 0.03, respectively. In addition, the fraction contained 17 bioactive constituents associated with the antibacterial, antioxidant, and wound healing properties that were identified using gas chromatography-mass spectrometry analysisMO leaf EtOAc fraction supports wound closure rate about 80% for treatments when compared with control group. Abbreviations used: MO: Moringa oleifera; EtOAc: Ethyl acetate; GC-MS: Gas Chromatography-Mass Spectrometry; HDF-D: Diabetic Human Dermal Fibroblast cells.

Efficiency of newly formulated camptothecin with ß-cyclodextrin-EDTA-Fe3O4 nanoparticle-conjugated nanocarriers as an anti-colon cancer (HT29) drug.

Camptothecin (CPT) is an anti-cancer drug that effectively treats various cancers, including colon cancer. However, poor solubility and other drawbacks have restricted its chemotherapeutic potential. To overcome these restrictions, CPT was encapsulated in CEF (cyclodextrin-EDTA-FE3O4), a composite nanoparticle of magnetic iron oxide (Fe3O4), and ß-cyclodextrin was cross-linked with ethylenediaminetetraacetic acid (EDTA). This formulation improved CPT's solubility and bioavailability for cancer cells. The use of magnetically responsive anti-cancer formulation is highly advantageous in cancer chemotherapy. The chemical characterisation of CPT-CEF was studied here. The ability of this nano-compound to induce apoptosis in HT29 colon cancer cells and A549 lung cancer cells was evaluated. The dose-dependent cytotoxicity of CPT-CEF was shown using MTT. Propidium iodide and Annexin V staining, mitochondrial membrane depolarisation (JC-1 dye), and caspase-3 activity were assayed to detect apoptosis in CPT-CEF-treated cancer cells. Cell cycle analysis also showed G1 phase arrest, which indicated possible synergistic effects of the nano-carrier. These study results show that CPT-CEF causes a dose-dependent cell viability reduction in HT29 and A549 cells and induces apoptosis in colon cancer cells via caspase-3 activation. These data strongly suggest that CPT could be used as a major nanocarrier for CPT to effectively treat colon cancer.

Stem cell therapies for myocardial infarction in clinical trials: bioengineering and biomaterial aspects.

Cardiovascular disease remains the leading cause of death and disability in advanced countries. Stem cell transplantation has emerged as a promising therapeutic strategy for acute and chronic ischemic cardiomyopathy. The current status of stem cell therapies for patients with myocardial infarction is discussed from a bioengineering and biomaterial perspective in this review. We describe (a) the current status of clinical trials of human pluripotent stem cells (hPSCs) compared with clinical trials of human adult or fetal stem cells, (b) the gap between fundamental research and application of human stem cells, (c) the use of biomaterials in clinical and pre-clinical studies of stem cells, and finally (d) trends in bioengineering to promote stem cell therapies for patients with myocardial infarction. We explain why the number of clinical trials using hPSCs is so limited compared with clinical trials using human adult and fetal stem cells such as bone marrow-derived stem cells.

The synthesis, characterization and in vivo study of mineral substituted hydroxyapatite for prospective bone tissue rejuvenation applications.

Minerals substituted apatite (M-HA) nanoparticles were prepared by the precipitation of minerals and phosphate reactants in choline chloride-Thiourea (ChCl-TU) deep eutectic solvent (DESs) as a facile and green way approach. After preparation of nanoparticles (F-M-HA (F=Fresh solvent)), the DESs was recovered productively and reprocess for the preparation of R-M-HA nanoparticles (R=Recycle solvent).The functional groups, phase, surface texture and the elemental composition of the M-HA nanoparticles were evaluated by advance characterization methods. The physicochemical results of the current work authoritative the successful uses of the novel (ChCl-TU) DESs as eco-friendly recuperate and give the medium for the preparation of M-HA nanoparticles. Moreover, the as-synthesized both M-HA nanoparticles exhibit excellent biocompatibility, consisting of cell co-cultivation and cell adhesion, in vivo according to surgical implantation of Wistar rats.

Stem Cell Therapies for Reversing Vision Loss.

Current clinical trials that evaluate human pluripotent stem cell (hPSC)-based therapies predominantly target treating macular degeneration of the eyes because the eye is an isolated tissue that is naturally weakly immunogenic. Here, we discuss current bioengineering approaches and biomaterial usage in combination with stem cell therapy for macular degeneration disease treatment. Retinal pigment epithelium (RPE) differentiated from hPSCs is typically used in most clinical trials for treating patients, whereas bone marrow mononuclear cells (BMNCs) or mesenchymal stem cells (MSCs) are intravitreally transplanted, undifferentiated, into patient eyes. We also discuss reported negative effects of stem cell therapy, such as patients becoming blind following transplantation of adipose-derived stem cells, which are increasingly used by 'stem-cell clinics'.

Micro-anatomical changes in major blood vessel caused by dengue virus (serotype 2) infection.

Dengue virus (DENV) has emerged as a major economic concern in developing countries, with 2.5 billion people believed to be at risk. Vascular endothelial cells (ECs) lining the circulatory system from heart to end vessels perform crucial functions in the human body, by aiding gas exchange in lungs, gaseous, nutritional and its waste exchange in all tissues, including the blood brain barrier, filtration of fluid in the glomeruli, neutrophil recruitment, hormone trafficking, as well as maintenance of blood vessel tone and hemostasis. These functions can be deregulated during DENV infection. In this study, BALB/c mice infected with DENV serotype 2 were analyzed histologically for changes in major blood vessels in response to DENV infection. In the uninfected mouse model, blood vessels showed normal architecture with intact endothelial monolayer, tunica media, and tunica adventitia. In the infected mouse model, DENV distorted the endothelium lining and disturbed the smooth muscle, elastic laminae and their supporting tissues causing vascular structural disarrangement. This may explain the severe pathological illness in DENV-infected individuals. The overall DENV-induced damages on the endothelial and it's supporting tissues and the dysregulated immune reactions initiated by the host were discussed.

Development of extended-voyaging anti-oxidant Linked Amphiphilic Polymeric Nanomicelles for Anti-Tuberculosis Drug Delivery.

Amphiphilic chitosan-graft-poly(caprolactone)/(ferulic acid) (CS-g-PCL/FA) multi-co-polymers were fabricated by microwave-assisted ring opening polymerization followed by an 1-ethyl-3-(3-dimethyl-aminopropyl) carbodiimide (EDC)-mediated coupling reaction and characterized by Fourier transformed infrared (FTIR) spectroscopy. Graft copolymers self-assembled into nanomicelles, and were able to incorporate rifampicin (RF) into their hydrophobic inner cores. X-ray diffraction (XRD) patterns were applied to characterize the crystal structures of graft polymers and the effects of RF on micelle morphology. Empty and RF-loaded CS-g-PCL/FA nanomicelles underwent swelling and degradation in acidic pH conditions. Scanning electron microscopy, transmission electron microscopy, and dynamic light scattering revealed that the self-assembled, RF-loaded micelles were spherical, with an average size of 100-210nm. An in vitro study conducted at 37°C demonstrated that RF and FA release from micelles at pH 5.3 was much faster than that at pH 7.4. The RF and FA release was significantly accelerated by switching to an acidic pH, owing to swelling of the micelles at lower pH values caused by the rapid degradation of ester and amide bonds present in the micelles. Fluorescence micrographs revealed successful entry of the polymeric micelles into A549cell lines. Thus, graft polymeric micelles have promising potential for delivery of hydrophobic antitubercular drugs and may improve therapeutic approaches for tuberculosis.

Xeno-free culture of human pluripotent stem cells on oligopeptide-grafted hydrogels with various molecular designs.

Establishing cultures of human embryonic (ES) and induced pluripotent (iPS) stem cells in xeno-free conditions is essential for producing clinical-grade cells. Development of cell culture biomaterials for human ES and iPS cells is critical for this purpose. We designed several structures of oligopeptide-grafted poly (vinyl alcohol-co-itaconic acid) hydrogels with optimal elasticity, and prepared them in formations of single chain, single chain with joint segment, dual chain with joint segment, and branched-type chain. Oligopeptide sequences were selected from integrin- and glycosaminoglycan-binding domains of the extracellular matrix. The hydrogels grafted with vitronectin-derived oligopeptides having a joint segment or a dual chain, which has a storage modulus of 25 kPa, supported the long-term culture of human ES and iPS cells for over 10 passages. The dual chain and/or joint segment with cell adhesion molecules on the hydrogels facilitated the proliferation and pluripotency of human ES and iPS cells.