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Biolmpacts - Volume:7 Issue: 3, Sep 2017

Biolmpacts
Volume:7 Issue: 3, Sep 2017

  • تاریخ انتشار: 1396/07/18
  • تعداد عناوین: 8
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  • Mohammad Rafi, Abass Alavi Pages 135-137
    The issue of human lifespan has long been a matter of controversy among scientists. In spite of the recent claim by Dong et al that human lifespan is limited to 115 years, with the mounting improvements in biotechnology and scientific understanding of aging, we may be confident that aging will slow down over the course of the current century extending human longevity much longer than 115 years.
  • Sarvenaz Sabouri-Rad, Reza Kazemi Oskuee, Asma Mahmoodi, Leila Gholami, Bizhan Malaekeh-Nikouei Pages 139-145
    Introduction
    Cationic polymers have the potential to be modified to achieve an ideal gene vector lacking viral vector defects. The aim of the present study was to improve polyallylamine (PAA) transfection efficiency and to reduce cytotoxicity by incorporating of cell-penetrating peptides.
    Methods
    To prepare the peptide-based polyplexes, PAA (15 kDa) was modified with two peptides (TAT and CyLoP-1) by covering the 0.5 and 1 percent of amines. Buffer capacity and DNA condensation ability of modified polymer, particle size and zeta potential of nanoparticles, cell viability, and transfection activity of vectors were evaluated.
    Results
    In low carrier to plasmid (C/P) weight ratios such as 0.5 and 1, the unmodified polymer was more capable to condense the DNA compared to the synthetized vectors. In C/P ratio of 2, the plasmid was fully condensed in all vectors. The size of polyplexes ranged from 195 to 240 nm. The zeta potential was almost as the same as PAA and varied from 25 to 27 mV. All polyplexes increased the buffer capacity compared to PAA. The transfection efficiency was improved compared to unmodified polymer especially in the vectors modified with 1% of TAT or CyLoP-1 peptides in C/P ratio of 2. The cytotoxicity of prepared vectors was less than PAA. In most ratios, the cytotoxicity of the CyLoP-1 modified samples was less than the TAT modified ones.
    Conclusion
    Modification of PAA with cell penetrating peptides improved the transfection activity of vector.
    Keywords: Cell penetrating peptides, Polyallylamine, Polyplexes, Transfection
  • Samaneh Rashtbari, Gholamreza Dehghan*, Reza Yekta, Abolghasem Jouyban Pages 147-153
    Introduction
    The study on the side effects of various drugs and compounds on macromolecules such as enzymes is an important issue for monitoring the alteration of structural and functional properties of them. Quercetin (3,5,7,3ʹ,4ʹ-pentahydroxyflavone, QUE), a polyphenolic flavonoid, widely found in fruits, vegetables and it is used as an ingredient in foods and beverages. This article shows an interaction of bovine liver catalase (BLC) with QUE using multispectroscopic methods.
    Methods
    In this work, the interaction between QUE and bovine liver catalase (BLC) was investigated using multi-spectroscopic methods including UV-vis absorption, fluorescence and circular dichroism (CD) spectroscopy and molecular docking studies.
    Results
    Fluorescence data at different temperatures, synchronous fluorescence, and circular dichroism studies revealed conformational changes in the BLC structure in the presence of different concentration of QUE. Also, the fluorescence quenching data showed that QUE can form non-fluorescent complex with BLC and quench its intrinsic emission by a static mechanism. The binding constant (Ka) for the interaction was 104, and the number of binding sites was obtained ~1. Thermodynamic parameters including ∆H, ∆S and ∆G changes were obtained, indicating that hydrophobic interactions play a main role in the complex formation. In vitro kinetic studies showed that QUE can inhibit BLC activity through non-competitive manner. Molecular docking study results were in good agreement with experimental data, confirming only one binding site on BLC for QUE at a cavity among the wrapping domain, threating arm and β-barrel.
    Conclusion
    The inhibitory effect of QUE on the activity of BLC demonstrated that high consumption of the flavenoids could be resulted in hazardous effects.
    Keywords: Bovine liver catalase, flavonoid, molecular docking, non-competitive inhibition, quercetin, static guenching
  • Mohsen Salmanpour, Ali Tamaddon*, Gholamhossein Yousefi, Soliman Mohammadi-Samani Pages 155-167
    Introduction
    Recent advances in the field of poly (2-oxazolines) as bio-inspired synthetic pseudopeptides have proven their potential biomedical applications such as drug delivery and tissue engineering.
    Methods
    In order to fabricate a biodegradable nano-assembly of poly (2-ethyl 2-oxazoline)-b-poly (benzyl L-glutamate), "graft-from" block copolymer synthesis method was used involving consecutive steps of cationic ring opening polymerization (CROP) of 2-ethyl-2-oxazoline (EOx), amine functionalization of pEOx using 1-Boc-piperazine and N-carboxyanhydride polymerization of γ-Benzyl-L-glutamate. Following hydrolysis of the protecting γ-Benzyl group, the double-hydrophilic block ionomer of pEOx-b-poly (L-glutamic acid) was prepared. The polymer samples were characterized by FTIR, 1H-NMR, size exclusion chromatography and differential scanning calorimetry (DSC). Self-assembling properties of the polymer samples in aqueous media was investigated by pyrene assay, dynamic light scattering, and transmission electron microscopy. MTT cytotoxicity assay was performed to determine the biocompatibility of pEOx-b-poly (L-glutamic acid) as a new compound in various tumor cell lines.
    Results
    The polymeric nano-assembly presented a uni-modal size distribution with the mean hydrodynamic diameter of 149.8 ± 10.6 nm and critical aggregation concentration of 60 µg/mL. The molecular weight of pEOx (~ 14 kDa) increased to ~20 kDa for pEOx-b-poly (L-glutamic acid) as determined by Debye plot, indicating a successful copolymerization. MTT assay showed that little to no practical cytotoxicity was found at concentrations below 1 mg/ mL.Therefore, a soluble and biocompatible block ionomer can be formed through hydrolysis of the copolymer nano-assembly.
    Conclusion
    Both pEOx-based copolymers can be considered for various potential applications such as loading and delivery of drugs, genes, and contrast agents either by chemical conjugation or physical loading.
    Keywords: poly (2-oxazolines) functionalization, graft-from synthesis, double hydrophilic block ionomer
  • Mina Sattari, Marziyeh Fathi, Mansour Daei, Hamid Erfan-Niya*, Jaleh Barar , Ali Akbar Entezami Pages 167-175
    Introduction
    Stimuli-responsive hydrogels, which indicate a significant response to the environmental change (e.g., pH, temperature, light, …), have potential applications for tissue engineering, drug delivery systems, cell therapy, artificial muscles, biosensors, etc. Among the temperature-responsive materials, poly (N-isopropylacrylamide) (PNIPAAm) based hydrogels have been widely developed and their properties can be easily tailored by manipulating the properties of the hydrogel and the composite material. Graphene oxide (GO), as a multifunctional and biocompatible nanosheet, can efficiently improve the mechanical strength and response rate of PNIPAAm-based hydrogels. Here, hydrogel composites (HCs) of PNIPAAm with GO was developed using the modified starch as a biodegradable cross-linker.
    Methods
    Micro/nanohydrogel composites were synthesized by free radical polymerization of NIPAAm in the suspension of different feed ratio of GO using maleate-modified starch (St-MA) as cross-linker and Tetrakis (hydroxymethyl) phosphonium chloride (THPC) as a strong oxygen scavenger. The HCs were characterized by FT-IR, DSC, TGA, SEM, and DLS. Also, the phase transition, swelling/deswelling behavior, hemocompatibility and biocompatibility of the synthesized HCs were investigated.
    Results
    The thermal stability, phase transition temperature and internal network crosslinking of HCs increases with increasing of the GO feed ratio. Also, the swelling/deswelling, hemolysis, and MTT assays studies confirmed that the HCs are a fast response, hemocompatible and biocompatible materials.
    Conclusion
    The employed facile approach for the synthesis of HCs yields an intelligent material with great potential for biomedical applications.
    Keywords: Hydrogel composite, Thermoresponsive, Hemolysis, Biocompatible, Swelling, deswelling
  • Samiullah Khan*, Fahad Naeem, Aamir Jalil, Nazar Muhammad Ranjha, Amina Riaz, Malik Salman Haider, Shoaib Sarwar, Fareha Saher, Samrin Afzal Pages 177-192
    Introduction
    The current work was aimed to design and synthesize novel crosslinked pH-sensitive gelatin/pectin (Ge/Pec) hydrogels using different polymeric ratios and to explore the effect of polymers and degree of crosslinking on dynamic, equilibrium swelling and in vitro release behavior of the model drug (Mannitol).
    Methods
    The Ge/Pec based hydrogels were prepared using glutaraldehyde as the crosslinker. Various structural parameters that affect their release behavior were determined like swelling study, porosity, sol-gel analysis, average molecular weight between crosslinks (Mc), volume fraction of polymer (V2,s), solvent interaction parameter (χ) and diffusion coefficient. The synthesized hydrogels were subjected to various characterization tools like Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and DSC differential scanning calorimetry (DSC) and scanning electron microscopy (SEM). an
    Results
    The hydrogels show highest water uptake and release at lower pH values. FTIR spectra showed interaction between Ge and Pec and loaded samples also showed the peak of drug which shows proper loading of the drug. DSC and TGA studies confirmed the thermal stability of hydrogel samples, while SEM showed the porous nature of hydrogels. The drug release followed non-Fickian diffusion or anomalous mechanism.
    Conclusion
    Aforementioned characterizations reveal the successful formation of copolymer hydrogels. pH-sensitive swelling ability and drug release behavior suggest that the rate of polymer chain relaxation and drug diffusion from these hydrogels are comparable which also predicts their possible use for site specific drug delivery.
    Keywords: Stimuli Responsive, Superabsorbent, Mannitol, Natural Polymers, Controlled Delivery
  • Abbas Asoudeh-Fard, Abolfazl Barzegari, Asal Golchin, Alireza Dehnad, Sepideh Bastani, Yadollah Omidi* Pages 193-198
    Introduction
    The oral tumor is the sixth most prevalent type of cancer worldwide and the second leading cause of cancer-related mortality. Although chemotherapy and immunotherapy are the main strategies for the treatment of oral cancer, an emergence of inevitable resistance to these treatment modalities is the major drawback that causes recurrence of the disease. Nowadays, probiotics have been suggested as adjunctive and complementary treatment modalities for improving the impacts of chemotherapy and immunotherapy agents. Probiotics, the friendly microflora in our bodies, contribute to the production of useful metabolites with positive effects on the immune system against various diseases such as cancer.
    Methods
    Lactobacillus plantarum is one of the most important bacteria, which commensally live in the human oral system. In the current study, the impacts of L. plantarum on maintaining oral system health were investigated, and the molecular mechanisms of inhibition of oral cancer KB cells mediated by L. plantarum were evaluated using real-time polymerase chain reaction (PCR) and FACS flow cytometry analyses.
    Results
    Our findings showed that L. plantarum is effective in the signal transduction of the oral cancer cells through upregulation and downregulation of PTEN and MAPK pathways, respectively.
    Conclusion
    Based on the biological effects of oral candidate probiotics candidate bacterium L. plantarum on functional expression of PTEN and MAPK pathways, this microorganism seems to play a key role in controlling undesired cancer development in the oral system. Taken all, L. plantarum is proposed as a potential candidate for probiotics cancer therapy.
    Keywords: Probiotics, Cell signalling, MAPK, PTEN, Oral cancer
  • Ali Mesgari Shadi, Mohammad Hossein Sarrafzadeh* Pages 199-206
    Introduction
    Single chain variable fragment (scFv) antibodies are reduced forms of the whole antibodies that could be regarded as an alternative tool for diagnostic and therapeutic purposes. The optimization of processes and environmental conditions is necessary to increase the production yields and enhance the productivity. This can result in a cost-effective process and respond to the high demand for these antibodies.
    Methods
    In this research, physical and chemical factors influencing the batch fermentation was investigated in 50 mL batch tubes using minimum media to find the optimum conditions for production of a single chain variable fragment antibody in the Escherichia coli HB2151. Experimental designs were used to screen the effective parameters and to optimize the main factors.
    Results
    Arabinose was used instead of IPTG as a cheaper and nontoxic inducer and its optimum concentration was determined 0.1% (w/w). Induction duration time and filling volume fraction were set on the relatively better states 24 hours and 1/10 respectively. Regarding our previous study, stationary phase of the cell growth was selected as induction start time that showed higher specific scFv production yields (YP/X) in the minimum media. Finally, a statistical experimental design was extended to a central composite design (CCD) and analysis was performed based on sucrose and sorbitol concentrations producing osmotic condition for induction. The optimum region in the contour plot for the periplasmic scFv production was an osmotic circle area with total sugar molarity 0.8 to 0.9.
    Conclusion
    Sugars such as sucrose and sorbitol producing osmotic conditions could lead to periplasmic scFv concentrations up to 2.85 mg/L of culture media improving scFv concentration near to five times of the average of the screening step (0.59 mg/L).
    Keywords: antibody, optimization, experimental design, inducer, scFv, osmotic condition