Green synthesis of strontium nanoparticles self‐assembled in the presence of carboxymethyl cellulose: an in vivo imaging study

Carboxymethyl cellulose (CMC) is one of the main derivatives of cellulose and is used as a drug carrier for hydrophobic and hydrophilic drugs, imaging in vivo, and biological applications. Encapsulation is a technology in which target compounds are coated with wall compounds to form microcapsules. This study reports a new chemical processing wet method for precipitation and encapsulation of strontium nanoparticles (Sr NPs) within CMC structures using a sonochemical method. Preparation parameters such as microwave power and irradiation time as well as morphology and particle size of Sr NPs were also investigated. Products were characterized by X‐ray diffraction, scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, thermogravimetric analysis and atomic force microscopy. In this study, CMC was used as a biological stabilizer in a retentive phase to encapsulate Sr NPs. For the first time, Sr NPs were synthesized using CMC in a cost‐effective, simple, fast, micellation‐assisted, ultrasound method. Sr NPs were encapsulated in green capping agent structures of either 1%, 2% or 3% weight to provide an efficient optical nanostructure with a high yield at wavelengths 200–700 nm for use in in vivo imaging studies.     

Scale-freeness of dominant and piecemeal perceptions during binocular rivalry

When two eyes are simultaneously stimulated by two inconsistent images, the observer’s perception switches between the two images every few seconds such that only one image is perceived at a time. This phenomenon is named binocular rivalry (BR). However, sometimes the perceived image is a piecemeal mixed of two stimuli known as piecemeal perceptions. In this study, a BR task was designed in which orthogonal gratings are presented to the two eyes. The subjects were trained to report 3 states: dominant perceptions (two state matching to perceived grating orientation) and the piecemeal perceptions (third state). We explored the scale-freeness of the BR percept durations considering the two dominant monocular states as well as the piecemeal transition state using detrended fluctuation analysis. Our results reproduced the previous finding of memory in the perceptual switches between the monocular perception states. Moreover, we showed that such memory also exists in the transitory periods of dichoptic piecemeal perceptions. These results support our hypothesis that the pool of unstable piecemeal perceptions could be regarded as separate multiple low-depth basin in the perceptual state landscape. Likewise, the transitions from these piecemeal state basins and stable monocular state basins are faced with resistance. Therefore there is inertia and memory (i.e. positive serial correlation) for the piecemeal dichoptic perception states as well as the monocular states.     

Adipose tissue‐derived mesenchymal stem cells and keratinocytes co‐culture on gelatin/chitosan/β‐glycerol phosphate nanoscaffold in skin regeneration

Using cell‐based engineered skin is an emerging strategy for treating difficult‐to‐heal wounds. To date, much endeavor has been devoted to the fabrication of appropriate scaffolds with suitable biomechanical properties to support cell viability and growth in the microenvironment of a wound. The aim of this research was to assess the impact of adipose tissue‐derived mesenchymal stem cells (AD‐MSCs) and keratinocytes on gelatin/chitosan/β‐glycerol phosphate (GCGP) nanoscaffold in full‐thickness excisional skin wound healing of rats. For this purpose, AD‐MSCs and keratinocytes were isolated from rats and GCGP nanoscaffolds were electrospun. Through an in vivo study, the percentage of wound closure was assessed on days 7, 14, and 21 after wound induction. Samples were taken from the wound sites in order to evaluate the density of collagen fibers and vessels at 7 and 14 days. Moreover, sampling was done on days 7 and 14 from wound sites to assess the density of collagen fibers and vessels. The wound closure rate was significantly increased in the keratinocytes‐AD‐MSCs‐scaffold (KMS) group compared with other groups. The expressions of vascular endothelial growth factor, collagen type 1, and CD34 were also significantly higher in the KMS group compared with the other groups. These results suggest that the combination of AD‐MSCs and keratinocytes seeded onto GCGP nanoscaffold provides a promising treatment for wound healing.     

Hybrid chitosan–ß‐glycerol phosphate–gelatin nano‐/micro fibrous scaffolds with suitable mechanical and biological properties for tissue engineering

Scaffold‐based tissue engineering is considered as a promising approach in the regenerative medicine. Graft instability of collagen, by causing poor mechanical properties and rapid degradation, and their hard handling remains major challenges to be addressed. In this research, a composite structured nano‐/microfibrous scaffold, made from a mixture of chitosan–ß‐glycerol phosphate–gelatin (chitosan–GP–gelatin) using a standard electrospinning set‐up was developed. Gelatin–acid acetic and chitosan ß‐glycerol phosphate–HCL solutions were prepared at ratios of 30/70, 50/50, 70/30 (w/w) and their mechanical and biological properties were engineered. Furthermore, the pore structure of the fabricated nanofibrous scaffolds was investigated and predicted using a theoretical model. Higher gelatin concentrations in the polymer blend resulted in significant increase in mean pore size and its distribution. Interaction between the scaffold and the contained cells was also monitored and compared in the test and control groups. Scaffolds with higher chitosan concentrations showed higher rate of cell attachment with better proliferation property, compared with gelatin‐only scaffolds. The fabricated scaffolds, unlike many other natural polymers, also exhibit non‐toxic and biodegradable properties in the grafted tissues. In conclusion, the data clearly showed that the fabricated biomaterial is a biologically compatible scaffold with potential to serve as a proper platform for retaining the cultured cells for further application in cell‐based tissue engineering, especially in wound healing practices. These results suggested the potential of using mesoporous composite chitosan–GP–gelatin fibrous scaffolds for engineering three‐dimensional tissues with different inherent cell characteristics. © 2015 Wiley Periodicals, Inc. Biopolymers 105: 163–175, 2016.     

Evaluation of SDS‐coated iron nanostructure on the gene expression of bio surfactant‐producing genes by Pseudomonas aeruginosa

Bio surfactants are natural surfactants that induce emulsification, displacement, increased solubility, and mobility of hydrophobic organic compounds. In this study, the gene expression of biosurfactant production genes by Pseudomonas aeruginosa in the presence of sodium dodecyl sulfate coated iron nanostructure (Fe/SDS) were evaluated. Emulsification Index and Surface Tension reduction test to check stability and emulsification the rhamnolipid were done. Purification was evaluated using thin layer chromatography (TLC) and expression of rhlA, mvfR, lasR, rhlR genes was determined using q‐PCR technique. Binding of nanoparticles to bio surfactants was confirmed by TEM. The best emulsification index, was by the sample that exposed to 1 mg/L Fe/SDS nanoparticles for 2 days. Rhamnolipid produced in the presence of nanoparticles had an acceptable ability to reduce surface tension. The Rf (retention factor) value obtained was 0.63 by chromatography. q‐PCR results showed that the expression of rhlA, mvfR, lasR, rhlR genes was significantly increased in Fe/SDS treated cells, which indicates the significant positive effect (P < 0.05) of nanoparticles on biosurfactant production of treated cells. While, SDS and Fe alone were not affected significantly (P > 0.05) on the expression of these genes. Our findings indicated the importance of nanoparticles in increasing the expression of genes involved in the bio surfactant production pathway of Pseudomonas aeruginosa.     

Supportive properties of basement membrane layer of human amniotic membrane enable development of tissue engineering applications

Human amniotic membrane (HAM) has been widely used as a natural scaffold in tissue engineering due to many of its unique biological properties such as providing growth factors, cytokines and tissue inhibitors of metalloproteinases. This study aimed at finding the most suitable and supportive layer of HAM as a delivery system for autologous or allogeneic cell transplantation. Three different layers of HAM were examined including basement membrane, epithelial and stromal layers. In order to prepare the basement membrane, de-epithelialization was performed using 0.5 M NaOH and its efficiency was investigated by histological stainings, DNA quantification, biomechanical testing and electron microscopy. Adipose-derived stromal cells (ASCs) and a human immortalized keratinocyte cell line (HaCaT) were seeded on the three different layers of HAM and cultured for 3 weeks. The potential of the three different layers of HAM to support the attachment and viability of cells were then monitored by histology, electron microscopy and (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Moreover, mechanical strengths of the basement membrane were assessed before and after cell culture. The results indicated that the integrity of extra cellular matrix (ECM) components was preserved after de-epithelialization and resulted in producing an intact basement amniotic membrane (BAM). Moreover, all three layers of HAM could support the attachment and proliferation of cells with no visible cytotoxic effects. However, the growth and viability of both cell types on the BAM were significantly higher than the other two layers. We conclude that growth stimulating effectors of BAM and its increased mechanical strength after culturing of ASCs, besides lack of immunogenicity make it an ideal model for delivering allogeneic cells and tissue engineering applications.     

Iodine-131-lipiodol therapy in hepatic tumours

The incidence of hepatocellular carcinoma (HCC) is worldwide sharply on the rise and patients with advanced disease carry a poor prognosis. HCC is the sixth most common cancer and the third leading cause of cancer associated deaths in the world. Intra-arterially administered ¹³¹I-Lipiodol is selectively retained by hepatocellular carcinomas, and has been used as a vehicle for delivery of therapeutic agents to these tumours. In this review we focus on the therapeutic indications, usefulness and methods of treatment with 131-Iodine Lipiodol.The effectiveness of ¹³¹I-Lipiodol treatment is proven both in the treatment of HCC with portal thrombosis and also as an adjuvant to surgery after the resection of HCCs. It is at least as effective as chemoembolization and is tolerated much better. Severe liver dysfunction represents theoretic contraindication for radioembolization as well as for TACE. In such cases ¹³¹I-Lipiodol is an alternative therapy option especially in tumours smaller than 6 cm.     

Galactosylated nanostructured lipid carriers for delivery of 5-FU to hepatocellular carcinoma

The aim of the present study was to design a targeted delivery system of 5-fluorouracil (5-FU) for hepatocellular carcinoma (HCC). Lactobionic acid (LB) was conjugated to stearyl amine (SA) by a chemical reaction. The nanostructured lipid carriers (NLCs), containing LB conjugate, lecithin, glyceryl monostearate, oil [oleic acid (OA) or Labrafac 5 or 10%], and 5-FU, were dissolved in alcohol/acetone, the oil phase was added to the aqueous phase containing Tween 80 or Solutol(?) HS15 (0.25 or 0.5%), and NLCs were prepared by an emulsification-solvent diffusion method. Physical properties and drug release were studied in NLCs. The thiazolyl blue tetrazolium bromide assay was used to study the cytotoxicity of NLCs on HepG(2) cells, and the cellular uptake of NLCs was determined by flow cytometry. Fourier transform infrared spectroscopy and (1)H-NMR spectra confirmed the successful conjugation of LB and SA. The optimized NLCs consisted of 0.5% Solutol HS15 and 10% OA oil. The particle size of these nanoparticles was 139.2 nm, with a zeta potential of -18 mV, loading efficiency of 34.2%, release efficiency after 2 hours of the release test was 72.6%, and crystallinity was 0.63%. The galactosylated NLCs of 5-FU were cytotoxic on the HepG(2) cell line in a half concentration of 5-FU and seems promising in reducing 5-FU dose in HCC.