Rozita Nasiri

Communal microaerophilic-aerobic biodegradation of Amaranth by novel NAR-2 bacterial consortium.

A novel bacterial consortium, NAR-2 which consists of Citrobacter freundii A1, Enterococcus casseliflavus C1 and Enterobacter cloacae L17 was investigated for biodegradation of Amaranth azo dye under sequential microaerophilic-aerobic condition. The NAR-2 bacterial consortium with E. casseliflavus C1 as the dominant strain enhanced the decolorization process resulting in reduction of Amaranth in 30 min. Further aerobic biodegradation, which was dominated by C. freundii A1 and E. cloacae L17, allowed biotransformation of azo reduction intermediates and mineralization via metabolic pathways including benzoyl-CoA, protocatechuate, salicylate, gentisate, catechol and cinnamic acid. The presence of autoxidation products which could be metabolized to 2-oxopentenoate was elucidated. The biodegradation mechanism of Amaranth by NAR-2 bacterial consortium was predicted to follow the steps of azo reduction, deamination, desulfonation and aromatic ring cleavage. This is for the first time the comprehensive microaerophilic-aerobic biotransformation pathways of Amaranth dye intermediates by bacterial consortium are being proposed.

γ-Fe2O3 nanoparticles filled polyvinyl alcohol as potential biomaterial for tissue engineering scaffold

Maghemite (γ-Fe2O3) nanoparticle with its unique magnetic properties is recently known to enhance the cell growth rate. In this study, γ-Fe2O3 is mixed into polyvinyl alcohol (PVA) matrix and then electrospun to form nanofibers. Design of experiments was used to determine the optimum parameter settings for the electrospinning process so as to produce elctrospun mats with the preferred characteristics such as good morphology, Youngs modulus and porosity. The input factors of the electrospinnning process were nanoparticles content (1-5%), voltage (25-35 kV), and flow rate (1-3 ml/h) while the responses considered were Youngs modulus and porosity. Empirical models for both responses as a function of the input factors were developed and the optimum input factors setting were determined, and found to be at 5% nanoparticle content, 35 kV voltage, and 1 ml/h volume flow rate. The characteristics and performance of the optimum PVA/γ-Fe2O3 nanofiber mats were compared with those of neat PVA nanofiber mats in terms of morphology, thermal properties, and hydrophilicity. The PVA/γ-Fe2O3 nanofiber mats exhibited higher fiber diameter and surface roughness yet similar thermal properties and hydrophilicity compared to neat PVA PVA/γ-Fe2O3 nanofiber mats. Biocompatibility test by exposing the nanofiber mats with human blood cells was performed. In terms of clotting time, the PVA/γ-Fe2O3 nanofibers exhibited similar behavior with neat PVA. The PVA/γ-Fe2O3 nanofibers also showed higher cells proliferation rate when MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay was done using human skin fibroblast cells. Thus, the PVA/γ-Fe2O3 electrospun nanofibers can be a promising biomaterial for tissue engineering scaffolds.

Synthesis, characterization and in vitro evaluation of exquisite targeting SPIONs-PEG-HER in HER2+ human breast cancer cells.

A stable, biocompatible and exquisite SPIONs-PEG-HER targeting complex was developed. Initially synthesized superparamagnetic iron oxide nanoparticles (SPIONs) were silanized using 3-aminopropyltrimethoxysilane (APS) as the coupling agent in order to allow the covalent bonding of polyethylene glycol (PEG) to the SPIONs to improve the biocompatibility of the SPIONs. SPIONs-PEG were then conjugated with herceptin (HER) to permit the SPIONs-PEG-HER to target the specific receptors expressed over the surface of the HER2+ metastatic breast cancer cells. Each preparation step was physico-chemically analyzed and characterized by a number of analytical methods including AAS, FTIR spectroscopy, XRD, FESEM, TEM, DLS and VSM. The biocompatibility of SPIONs-PEG-HER was evaluated in vitro on HSF-1184 (human skin fibroblast cells), SK-BR-3 (human breast cancer cells, HER+), MDA-MB-231 (human breast cancer cells, HER-) and MDA-MB-468 (human breast cancer cells, HER-) cell lines by performing MTT and trypan blue assays. The hemolysis analysis results of the SPIONs-PEG-HER and SPIONs-PEG did not indicate any sign of lysis while in contact with erythrocytes. Additionally, there were no morphological changes seen in RBCs after incubation with SPIONs-PEG-HER and SPIONs-PEG under a light microscope. The qualitative and quantitative in vitro targeting studies confirmed the high level of SPION-PEG-HER binding to SK-BR-3 (HER2+ metastatic breast cancer cells). Thus, the results reflected that the SPIONs-PEG-HER can be chosen as a favorable biomaterial for biomedical applications, chiefly magnetic hyperthermia, in the future.

In vitro evaluation of actively targetable superparamagnetic nanoparticles to the folate receptor positive cancer cells

Engineering of a physiologically compatible, stable and targetable SPIONs-CA-FA formulation was reported. Initially fabricated superparamagnetic iron oxide nanoparticles (SPIONs) were coated with citric acid (CA) to hamper agglomeration as well as to ameliorate biocompatibility. Folic acid (FA) as a targeting agent was then conjugated to the citric acid coated SPIONs (SPIONs-CA) for targeting the specific receptors expressed on the FAR+ cancer cells. Physiochemical characterizations were then performed to assure required properties like stability, size, phase purity, surface morphology, chemical integrity and magnetic properties. In vitro evaluations (MTT assay) were performed on HeLa, HSF 1184, MDA-MB-468 and MDA-MB-231cell lines to ensure the biocompatibility of SPIONs-CA-FA. There were no morphological changes and lysis in contact with erythrocytes recorded for SPIONs-CA-FA and SPIONs-CA. High level of SPIONs-CA-FA binding to FAR+ cell lines was assured via qualitative and quantitative in vitro binding studies. Hence, SPIONs-CA-FA was introduced as a promising tool for biomedical applications like magnetic hyperthermia and drug delivery. The in vitro findings presented in this study need to be compared with those of in vivo studies.

Fabrication and evaluation of polymeric membranes for blood dialysis treatments using functionalized MWCNT based nanocomposite and sulphonated-PES

The use of polyethersulfone (PES) based membranes for dialysis therapy is increasing, but the transformation and adsorption of blood proteins, destruction of red blood cells, and thrombosis responses against PES membrane can raise severe blood reactions affecting the rate of morbidity and mortality of hemodialysis (HD) patients. In this work, the performance and biocompatibility of PES membranes were improved by sulfonation and nanocomposites (NCs) additives. Acid functionalized multiwall carbon nanotubes (f-MWCNT) and polyvinylpyrrolidone (PVP) were used for NCs preparation and then they were incorporated into sulfonated-polyethersulfone (S-PES) based membranes. The hydrophilic part of f-MWCNT contributed to the –COOH and –OH groups, whereas sulfonated polymer provided the –SO2H group in the membrane composition. The formulated HD membranes were characterized by FTIR, FESEM and contact angle. The AFM was used for the estimation of the surface roughness and surface profile studies, whereas flux rate, and rejection rate was also determined. The biocompatibility results revealed that sulfonated-NCs based membranes had reduced 55% (BSA), 65% (lysozyme) adsorption and 74.80% hemolysis process. It also demonstrated higher clotting time of prothrombin (PT), thrombin (TT), activated partial thrombin time (APTT), plasma re-calcification time (PRT). The dialysis results indicated that, compared to the pristine PES membrane, the clearance ratio of lysozyme, urea and creatinine solutes increased up to 32.4%, 59.2% and 57.3%, respectively. Thus, the blending of S-PES and NCs in the PES membrane highly improved the biocompatibility and removal ability of uremic solutes.

Antioxidant Activity and ROS-Dependent Apoptotic Effect of Scurrula ferruginea (Jack) Danser Methanol Extract in Human Breast Cancer Cell MDA-MB-231

Scurrula ferruginea (Jack) Danser is one of the mistletoe species belonging to Loranthaceae family, which grows on the branches of many deciduous trees in tropical countries. This study evaluated the antioxidant activities of S. ferruginea extracts. The cytotoxic activity of the selected extracts, which showed potent antioxidant activities, and high phenolic and flavonoid contents, were investigated in human breast cancer cell line (MDA-MB-231) and non-cancer human skin fibroblast cells (HSF-1184). The activities and characteristics varied depending on the different parts of S. ferruginea, solvent polarity, and concentrations of extracts. The stem methanol extract showed the highest amount of both phenolic (273.51 ± 4.84 mg gallic acid/g extract) and flavonoid contents (163.41 ± 4.62 mg catechin/g extract) and strong DPPH• radical scavenging (IC50 = 27.81 μg/mL) and metal chelation activity (IC50 = 80.20 μg/mL). The stem aqueous extract showed the highest ABTS•+ scavenging ability. The stem methanol and aqueous extracts exhibited dose-dependent cytotoxic activity against MDA-MB-231 cells with IC50 of 19.27 and 50.35 μg/mL, respectively. Furthermore, the extracts inhibited the migration and colony formation of MDA-MB-231 cells in a concentration-dependent manner. Morphological observations revealed hallmark properties of apoptosis in treated cells. The methanol extract induced an increase in ROS generation and mitochondrial depolarization in MDA-MB-231 cells, suggesting its potent apoptotic activity. The present study demonstrated that the S. ferruginea methanol extract mediated MDA-MB-231 cell growth inhibition via induction of apoptosis which was confirmed by Western blot analysis. It may be a potential anticancer agent; however, its in vivo anticancer activity needs to be investigated.

Bio-corrosion behavior and mechanical characteristics of magnesium-titania-hydroxyapatite nanocomposites coated by magnesium-oxide flakes and silicon for use as resorbable bone fixation material

This study was aimed to improve of the corrosion resistance and mechanical properties of Mg/15TiO2/5HA nanocomposite by silicon and magnesium oxide coatings prepared using a powder metallurgy method. The phase evolution, chemical composition, microstructure and mechanical properties of uncoated and coated samples were characterized. Electrochemical and immersion tests used to investigate the in vitro corrosion behavior of the fabricated samples. The adhesion strength of ~36MPa for MgO and ~32MPa for Si/MgO coatings to substrate was measured by adhesion test. Fabrication a homogenous double layer coating with uniform thicknesses consisting micro-sized particles of Si as outer layer and flake-like particles of MgO as the inner layer on the surface of Mg/15TiO2/5HA nanocomposite caused the corrosion resistance and ductility increased whereas the ultimate compressive stress decreased. However, after immersion in SBF solution, Si/MgO-coated sample indicates the best mechanical properties compared to those of the uncoated and MgO-coated samples. The increase of cell viability percentage of the normal human osteoblast (NHOst) cells indicates the improvement in biocompatibility of Mg/15TiO2/5HA nanocomposite by Si/MgO coating.

Trastuzumab-decorated nanoparticles for in vitro and in vivo tumor-targeting hyperthermia of HER2+ breast cancer

In this study, a magnetic core-shell modified tumor-targeting nanocarrier (MNPs-PEG-TRA) was engineered and demonstrated for the efficient in vitro and in vivo hyperthermia treatment of breast cancer. Magnetic nanoparticles were used as the initial nanocarriers and modified via PEGylation followed by immobilization of Trastuzumab (TRA) with tumor-targeting function towards cancer cells. The hyperthermia performance of the developed targeting drug delivery system was explored using an in vitro study with SK-BR-3 cancer cells and an in vivo study using animal models (mouse) with DMBA-induced breast cancer. The average size of the engineered system was about 100 nm and its zeta potential was about +13 mV, whereby the stability of the system in biological media is enormously enhanced while the possibility of it being removed via the immune system is diminished. The investigation was pursued based on comparing the changes in growth inhibition rates of HSF 1184, MDA-MB-231, MDA-MB-468 and SK-BR-3 cell lines at different temperatures (37 °C, 40 °C, 42 °C, and 45 °C). Compared with bare MNPs and MNPs-PEG, a remarkably enhanced hyperthermia effect using MNPs-PEG-TRA was observed not only in cultured SK-BR-3 cells in vitro but also in an in vivo DMBA tumor bearing mice model. These results are attributed to an about 4 fold higher concentration of MNPs-PEG-TRA carriers in the tumor site compared to the other organs confirming the considerable potential of the magnetic tumor-targeting hyperthermia concept for breast cancer treatment.

Cervicare™ induces apoptosis in HeLa and CaSki cells through ROS production and loss of mitochondrial membrane potential

Cervicare™ is a poly-herbal preparation comprised of a combination of 6 plants; most have demonstrated antimicrobial and anticancer properties in preclinical studies. The effect of the ethanol and aqueous extracts of Cervicare™ on cell proliferation and apoptosis using cervical cancer HeLa and CaSki cells was investigated for the first time in the present study. MTT assay results showed that Cervicare™ extracts exerted time- and dose-dependent inhibition of cell viability. The hallmark properties of apoptosis like cell shrinkage and cytoplasmic condensation were observed using an inverted phase contrast microscope, ethidium bromide/acridine orange and Hoechst 33342/propidium iodide fluorescent staining methods. Furthermore, our results demonstrated that Cervicare™ extracts induced apoptosis in HeLa and CaSki cells by ROS generation and mitochondrial depolarization in a concentration dependent manner. The results showed that Cervicare™ extracts were capable of suppressing cell migration and inhibiting colony formation in a dose-dependent manner. Moreover, western blot analysis demonstrated the involvement of a mitochondria-dependent apoptosis pathway in the apoptosis inducing activity of Cervicare™ ethanol extract in HeLa cells. GC-MS analysis of the ethanolic extract afforded the identification of 40 substances, showing that it was primarily composed of anti-cancerous compounds such as xanthorrhizol (60.40%), octacosane (9.93%) and squalene (1.24%). Together, these results point out the Cervicare™ mediated inhibition of HeLa cell growth via induction of apoptosis and that it may be a potential anticancer agent which deserves further investigation.

Identification of Biodegradation Related Genes from Bacterial Consortium NAR-2

In this study, PCR amplification of biodegradation related genes from NAR-2 bacterial consortium was accomplished. NAR-2 bacterial consortium consists of Citrobacter freundii A1, Enterococcus casseliflavus C1 and Enterobacter cloacae L17. The amplified genes were sequenced, bioinformatically analyzed and compared with the sequences from GenBank database of National Centre of Biotechnology Information (NCBI) using BLASTn and BLASTp search tools. The assembled sequences represented almost >70% of similarity to biodegradation related genes. These genes may act as a key intermediate enzyme in biodegradation pathway.