The effect of Nano-liposomal sodium nitrite on smooth muscle cell growth in a tissue-engineered small-diameter vascular graft.

BACKGROUND: Nitric oxide is a chemical agent produced by endothelial cells in a healthy blood vessel, inhibiting the overgrowth of vascular smooth muscle cells and regulating vessel tone. Liposomes are biocompatible and biodegradable drug carriers with a similar structure to cell bilayer phospholipid membrane that can be used as useful nitric oxide carriers in vascular grafts. METHOD: Using a custom-designed apparatus, the sheep carotid arteries were decellularized while still maintaining important components of the vascular extracellular matrix (ECM), allowing them to be used as small-diameter vascular grafts. A chemical signal of sodium nitrite was applied to control smooth muscle cells' behavior under static and dynamic cell culture conditions. The thin film hydration approach was used to create nano-liposomes, which were then used as sodium nitrite carriers to control the drug release rate and enhance the amount of drug loaded into the liposomes. RESULTS: The ratio of 80:20:2 for DPPC: Cholesterol: PEG was determined as the optimum formulation of the liposome structure with high drug encapsulation efficiency (98%) and optimum drug release rate (the drug release rate was 40%, 65%, and 83% after 24, 48, and 72 h, respectively). MTT assay results showed an improvement in endothelial cell proliferation in the presence of nano-liposomal sodium nitrite (LNS) at the concentration of 0.5 µg/mL. Using a suitable concentration of liposomal sodium nitrite (0.5 µg/mL) put onto the constructed scaffold resulted in the controllable development of smooth muscle cells in the experiment. The culture of smooth muscle cells in a pulsatile perfusion bioreactor indicated that in the presence of synthesized liposomal sodium nitrite, the overgrowth of smooth muscle cells was inhibited in dynamic cell culture conditions. The mechanical properties of ECM graft were measured, and a multi-scale model with an accuracy of 83% was proposed to predict mechanical properties successfully. CONCLUSION: The liposomal drug-loaded small-diameter vascular graft can prevent the overgrowth of SMCs and the formation of intimal hyperplasia in the graft. Aside from that, the effect of LNS on endothelial has the potential to stimulate endothelial cell proliferation and re-endothelialization.

EphA2 Targeted Doxorubicin-Nanoliposomes for Osteosarcoma Treatment.

PURPOSE: To employ Doxorubicin-loaded liposomes, modified with YSA-peptide to target EphA2, to reduce adverse effects against primary bone cells and maximize toxicity against Saos-2 osteosarcoma cells. METHODS: PEGylated liposomes were prepared by thin film method using Dipalmitoylphosphatidylcholine (DPPC), cholesterol and distearylphosphatidylethanolamine-polyethyleneglycol conjugate (DSPE-mPEG) in 67.9:29.1:3 M ratios, and loaded with DOX (L-DOX) by pH-gradient method. Targeted liposomes (YSA-L-DOX), were prepared by conjugating YSA-peptide to DSPE-mPEG. Liposomes were physicochemically characterized and tested in cellular toxicity assays. RESULTS: YSA conjugation efficiency was >98%. Size and polydispersity index of both L-DOX and YSA-L-DOX were around 88 nm and 0.188, respectively. Both had similar zeta potential, and 85% DOX loading efficiencies. DOX release kinetics followed the Korsmeyer-Peppa model, and showed comparable release for both formulations from 1-8 h, and a plateau of 29% after 48 h. Both formulations could be stably stored for ≥6 months at 4°C in the dark. Toxicity assays showed a significant 1.91-fold higher cytotoxicity compared to free DOX in the Saos-2 cells, and 2-fold lesser toxicity in primary bone cells compared to the Saos-2 cells. Cellular uptake studies showed higher and more nuclear uptake in YSA-L-DOX compared to L-DOX treated cells. CONCLUSIONS: YSA-L-DOX vesicles might be effective for targeted treatment of osteosarcoma.

Three-dimensional culture of differentiated endometrial stromal cells to oligodendrocyte progenitor cells (OPCs) in fibrin hydrogel.

Neural tissue engineering is one of the most promising strategies for treatment of nerve tissue injuries. Three-dimensional (3D) environment mimics in vivo conditions for cells. 3D distribution and growth of the cells within the scaffold are both important for neural tissue engineering. In this study, endometrial stromal cell-derived oligodendrocyte progenitor cells (EnSC-derived OPCs) were cultured in fibrin gel and cell differentiation and viability were evaluated after 8 days of post-culture. The structural and mechanical characteristics of fibrin gel-like scaffold were examined with rheological analysis. EnSCs were isolated from donor tissue and were induced to OPCs with growth factors (FGF2/EGF/PDGF-AA) for 12 days, then were cultured in fibrin gel with Triiodothyronine (T3) medium for another 8 days. The viability of cells was analyzed using MTT assay for a period of 8 days culturing in a fibrin matrix. Structure of fibrin matrix and cell morphology was analyzed with SEM. TEM, immunostaining and quantitative RT-PCR was performed for OPCs markers after cell culturing in fibrin matrix. Cell viability is enhanced in fibrin matrix after 8 days. SEM and TEM show that cells are in good integration with nano-fibers. Moreover, immunohistochemistry and quantitative RT-PCR of OPCs differentiation markers showed that Olig2, Sox10, PDGFRa, CNP, and A2B5 are expressed after 8 days culturing within fibrin matrix. Fibrin can provide a suitable 3-D scaffold for EnSCs differentiated cells for the regeneration of CNS.

Codelivery of doxorubicin and JIP1 siRNA with novel EphA2-targeted PEGylated cationic nanoliposomes to overcome osteosarcoma multidrug resistance.

PURPOSE: Osteosarcoma (OS) mostly affects children and young adults, and has only a 20%-30% 5-year survival rate when metastasized. We aimed to create dual-targeted (extracellular against EphA2 and intracellular against JNK-interacting protein 1 [JIP1]), doxorubicin (DOX)-loaded liposomes to treat OS metastatic disease. MATERIALS AND METHODS: Cationic liposomes contained N-[1-(2,3-dioleoyloxy)propyl]-N,N,N-trimethylammonium methyl-sulfate (DOTAP), cholesterol, 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC), and distearoyl-phosphatidylethanolamine-methyl-poly(ethylene glycol) (DSPE-mPEG) conjugate. EphA2 targeting was accomplished by conjugating YSA peptide to DSPE-mPEG. Vesicles were subsequently loaded with DOX and JIP1 siRNA. RESULTS: Characteristics assessment showed that 1) size of the bilayered particles was 109 nm; 2) DOX loading efficiency was 87%; 3) siRNA could be successfully loaded at a liposome:siRNA ratio of >24:1; and 4) the zeta potential was 18.47 mV. Tumor-mimicking pH conditions exhibited 80% siRNA and 50.7% DOX sustained release from the particles. Stability studies ensured the protection of siRNA against degradation in serum. OS cell lines showed increased and more pericellular/nuclear localizations when using targeted vesicles. Nontargeted and targeted codelivery caused 70.5% and 78.6% cytotoxicity in OS cells, respectively (free DOX: 50%). Targeted codelivery resulted in 42% reduction in the siRNA target, JIP1 mRNA, and 46% decrease in JIP1 levels. CONCLUSION: Our dual-targeted, DOX-loaded liposomes enhance toxicity toward OS cells and may be effective for the treatment of metastatic OS.

A comprehensive mathematical model of drug release kinetics from nano-liposomes, derived from optimization studies of cationic PEGylated liposomal doxorubicin formulations for drug-gene delivery.

This study focuses on the development of a universal mathematical model for drug release kinetics from liposomes to allow in silico prediction of optimal conditions for fine-tuned controlled drug release. As a prelude for combined siRNA-drug delivery, nanoliposome formulations were optimized using various mole percentages of a cationic lipid (1,2-dioleoyl-3-trimethylammonium-propane, DOTAP) in the presence or absence of 3 mol% distearoyl phosphoethanolamine, polyethylene glycol (PEG-2000mDSPE). Outcome parameters were particle size, zeta potential, entrapment efficiency, in vitro drug release, and tumor cell kill efficiency. The optimized formula (containing 20% DOTAP with 3% DSPE-mPEG(2000) was found to be stable for six months, with round-shaped particles without aggregate formation, an average diameter of 71 nm, a suitable positive charge, and 89% drug encapsulation efficiency (EE). The 41% drug release during 6 h confirmed controlled release. Furthermore, the release profiles as functions of pH and temperature were investigated and the kinetics of the drug release could adequately be fitted to Korsmeyer-Peppas' model by multiple regression analysis. The statistical parameters confirmed good conformity of final models. Functionality of the novel cationic liposome formulations (± DOX) was tested on osteosarcoma (OS) cell lines. Increased OS cell toxicity (1.3-fold) was observed by the DOX-loaded vs. the free DOX. A feasibility pilot showed that siRNA could be loaded efficiently as well. In conclusion, we have established a predictive mathematical model for the fine-tuning of controlled drug release from liposomal formulations, while creating functional drug-delivery liposomes with potential for siRNA co-delivery to increase specificity and efficacy.

Preparation of PEGylated cationic nanoliposome-siRNA complexes for cancer therapy.

Cationic liposomes have been investigated as non-viral vectors for gene delivery for more than a decade to overcome challenges associated with viral gene delivery. However, due to instability of liposomes, siRNA delivery is still a serious problem. In this study, we developed stealth PEGylated liposome formulations and focused on the effects of PEGylated liposomes on parameters related to size, zeta potential, polydispersity index, siRNA-loading efficiency and long-term stability of the siRNA-liposome complex. We were able to generate siRNA lipoplexes that could be very efficiently loaded, did not aggregate, could be stored at 4 °C for at least 6 months with only marginal release (1-5%) of siRNA and enhanced intracellular delivery of siRNA. Moreover, we could demonstrate that PEGylation positively contributed to all these parameters compared to liposomes, which were not PEGylated. The prepared lipoplex was successfully silenced J1P1 expression in MG-63 osteosarcoma cell line. In conclusion, our novel PEGylated liposomes have high potential for systemic delivery of siRNA and can improve in vivo stability of free siRNA and also siRNA lipoplexes.

New liposomal doxorubicin nanoformulation for osteosarcoma: Drug release kinetic study based on thermo and pH sensitivity.

A novel approach was developed for the preparation of stealth controlled-release liposomal doxorubicin. Various liposomal formulations were prepared by employing both thin film and pH gradient hydration techniques. The optimum formulation contained phospholipid and cholesterol in 1:0.43 molar ratios in the presence of 3% DSPE-mPEG (2000). The liposomal formulation was evaluated by determining mean size of vesicle, encapsulation efficiency, polydispersity index, zeta potentials, carrier's functionalization, and surface morphology. The vesicle size, encapsulation efficiency, polydispersity index, and zeta potentials of purposed formula were 93.61 nm, 82.8%, 0.14, and -23, respectively. Vesicles were round-shaped and smooth-surfaced entities with sharp boundaries. In addition, two colorimetric methods for cytotoxicity assay were compared and the IC50 (the half maximal inhibitory concentration) of both methods for encapsulated doxorubicin was determined to be 0.1 µg/ml. The results of kinetic drug release were investigated at several different temperatures and pH levels, which showed that purposed formulation was thermo and pH sensitive.

Surface modification of polypropylene membrane by polyethylene glycol graft polymerization.

Polypropylene hollow fiber microporous membranes have been used in a wide range of applications, including blood oxygenator. The hydrophobic feature of the polypropylene surface causes membrane fouling. To minimize fouling, a modification consisting of three steps: surface activation in H2 and O2 plasma, membrane immersion in polyethylene glycol (PEG) and plasma graft polymerization was performed. The membranes were characterized by contact angle measurement, Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), tensile test, scanning electron microscopy (SEM) and atomic force microscopy (AFM). Oxygen transfer of modified membranes was also tested. The stability of grafted PEG was measured in water and in phosphate buffer saline (PBS) at 37°C. Blood compatibility of modified surfaces was evaluated by the platelet adhesion method. Water contact angel reduction from 110° to 72° demonstrates the enhanced hydrophilicity, and XPS results verify the presence of oxygenated functional groups due to the peak existence in 286 eV as a result of PEG grafting. The results clearly indicate that plasma graft-polymerization of PEG is an effective way for antifouling improvement of polypropylene membranes. Also, the results show that oxygen transfer changes in PEG grafted membranes are not significant.

An inhibitory enzyme electrode for hydrogen sulfide detection.

An enzymatic biosensing system has been developed to study the capability of ascorbate oxidase (AOx), EC (1.10.3.3), in hydrogen sulfide (H2S) detection, based on the inhibition of AOx activity. The immobilization parameters including glutaraldehyde (GA) concentration and pH were optimized using experimental design. The optimized values of GA concentration and pH were found to be 12.5% (w/w) and 7, respectively, where the enzymatic reaction reached the steady-state level within 55 s. A linear relationship was observed between the decrease in the oxygen concentration and H2S concentration, where H2S concentration is in the range of 1-15 mg/L. Moreover, to investigate the selectivity of the biosensor, a certain H2S concentration (9 mg/L) was used against different ions. The results indicated that Fe(3+) and SO4(-2) ions had no significant (11% error) effect on the H2S detection. The operational stability of the biosensing system was determined in terms of response to H2S concentration, at optimal working conditions. The enzyme electrode could retain 73% of its original sensitivity after this period, which has made it possible for the system to measure H2S with concentrations as low as 0.5 mg/L.