Biosensors: Types, features, and application in biomedicine

Fast and precise diagnostic techniques are required for the treatment of many disorders. Biosensors are one of the diagnostic devices that are applicable in biological and medical sciences. Biosensors could be utilized to recognize biological molecules with high sensitivity. Biosensors are consisted of different components and have different types. Each type of biosensor is used in a particular field according to its specific features. Nanobodies are a novel class of antibodies with small size, high affinity, and specificity to their target. The unique properties of nanobodies make them appropriate tools for diagnostic applications. In this paper, we review biosensors, and their features and roles in medicine. Antibody/nanobody-based biosensors are also specifically discussed.

[Optimization of refolding of human vascular endothelial growth factor-A121]

Background: vascular endothelial growth factor [VEGF] plays an important role in development of new blood vessel and angiogenesis. Human VEGF121is smallest member of VEGF family. Production of active and correct form of VEGF is the m6st challenging issue

Methods: here we described a method for optimization of refolding of VEGF121 which was expressed in bacterial host. Enzyme linked immunosorbent assay and proliferation assay of human endothelial cells was performed to monitor refolding and functional assay ofVEGFlz1

Results: using described method VEGF was in correct fold and detected by antibody in ELISA. Furthermore, VEGF stimulated proliferation of human endothelial cells in dose-dependent manner

Conclusion: refolded VEGF has potential for stem cell differentiation

An overview on application of phage display technique in immunological studies

Phage display is very strong technique in drug discovery and development. Phage display has many applications in improving the immunological studies. Development of monoclonal antibody, peptides, peptidomimetics and epitope mapping are main application of phage display. Selection of monoclonal antibody or peptides that are displayed on the surface of the phages can be occurred through biopanning process. In biopanning process phage library is incubated with antigen and particular phages can be identified and isolated. Increasing the stringency in the biopanning rounds can be help to select phages with high affinity and specificity. Here, we describe an overview of phage display application with focusing on monoclonal antibody production and epitope mapping.

Recombinant expression and purification of functional vascular endothelial growth factor-121 in the baculovirus expression system

Objective To express human vascular endothelial growth factor121 (VEGF121) in insect cells. Methods A gene construct containing VEGF was cloned in the pFastBac-HTA vector, followed by transformation in DH10BAC. The recombinant bacmid was then extracted, and transfected into Sf9 insect cells. The transfected cells were harvested, and then VEGF expression was confirmed by western blotting using specific antibodies. The tube formation assay was used for functional assessment of VEGF. Results Our results showed that VEGF could be successfully expressed in the baculovirus system. Purified VEGF was able to stimulate in vitro tube formation of human endothelial cells. Conclusions Results from this study demonstrated that the recombinantly-produced VEGF can be considered as a promising candidate for therapeutic purposes.

Inhibitory effect of gold nanoparticles conjugated with interferon gamma and methionine on breast cancer cell line

Objective: To develop a gold nanoparticles complex conjugated with interferon-gamma (IFN-γ) and methionine along with application of hyperthermia using near-infrared laser beams for the treatment of cancer cells. Methods: Gold nanorods (10 nm) were conjugated with IFN-γ and methionine using carbodiimide family and characterized after purification by dialysis bags. Breast cancer cells were cultured and incubated with gold nanorods at different concentrations followed by irradiation with near-infrared laser beam. Samples were then evaluated for their viability in order to determine the effect of treatment and variables by MTT assy. Results: Zetasizer results confirmed the conjugation of gold nanorods with methionine and IFN-γ. The median percentage of cell viability in 0.30 μg/mL concentration of gold nanorods was 82%. The cell viability reached to 85% at the same concentration of gold nanorods, which existed in the assayed complex. The results of MTT assay showed that the 0.60 μg/mL concentration of gold nanoparticles complex was toxic on tumor cells (P < 0.05). After exposure to hyperthermia, the viability of cells at 6 min decreased to 77% in 0.30 μg/mL concentration of gold nanorods complex. Conclusions: The size and concentration of gold nanorods was not cytotoxic. However, their presence during irradiation near-infrared laser increased the number of dead cells during the treatment of cells.

Recombinant expression and purification of functional vascular endothelial growth factor-121 in the baculovirus expression system

OBJECTIVE@#To express human vascular endothelial growth factor121 (VEGF121) in insect cells.@*METHODS@#A gene construct containing VEGF was cloned in the pFastBac-HTA vector, followed by transformation in DH10BAC. The recombinant bacmid was then extracted, and transfected into Sf9 insect cells. The transfected cells were harvested, and then VEGF expression was confirmed by western blotting using specific antibodies. The tube formation assay was used for functional assessment of VEGF.@*RESULTS@#Our results showed that VEGF could be successfully expressed in the baculovirus system. Purified VEGF was able to stimulate in vitro tube formation of human endothelial cells.@*CONCLUSIONS@#Results from this study demonstrated that the recombinantly-produced VEGF can be considered as a promising candidate for therapeutic purposes.

Feasibility of electrochemical oxidation process for treatment of saline wastewater

Background: High concentration of salt makes biological treatment impossible due to bacterial plasmolysis. The present research studies the process of electrochemical oxidation efficiency and optimal levels as important factors affecting pH, salt concentration, reaction time and applied voltage

Methods: The sample included graphite electrodes with specifications of 2.5 cm diameter and 15 cm height using a reactor with an optimum capacity of 1 L. Sixty samples were obtained with the aid of the experiments carried out in triplicates for each factor at 5 different levels. The entire experiments were performed based on standard methods for water and waste water treatments

Results: Analysis of variance carried out on effect of pH, salt concentration, reaction time and flow intensity in elimination of chemical oxygen demand [COD] showed that they are significant factors affecting this process and reduce COD with a coefficient interval of 95% and test power of 80%. Scheffe test showed that at optimal level, a reaction time of 1 hour, 10 g/L concentration, pH = 9 and 15 V electrical potential difference were obtained

Conclusion: Waste waters containing salt may contribute to the electro-oxidation process due to its cations and anions. Therefore, the process of electrochemical oxidation with graphite electrodes could be a proper strategy for the treatment of saline wastewater where biological treatment is not possible

Effect of alpha-lipoic acid on blood glucose, insulin resistance and glutathione peroxidase of type 2 diabetic patients

To examine the effects of alpha-lipoic acid [ALA] treatment over a period of 2 months on fasting blood glucose [FBG], insulin resistance [IR], and glutathione peroxidase [GH-Px] activity in type 2 diabetes [T2DM] patients. This study took place in Motahari Clinic, Shiraz, Iran, which is affiliated to Shiraz University of Medical Sciences from May to October 2006. Type 2 DM patients [n=57] were divided into 2 groups to receive either ALA [300 mg daily] or placebo by systematic randomization, and were followed-up for 8 weeks. After an overnight fasting and 2 hours after breakfast, patients' blood samples were drawn and tested for FBG, 2 hours PPG, serum insulin level, and GH-Px activity. The result of the study showed a significant decrease in FBG and PPG levels, IR-Homeostasis Model Assessment [IR-HOMA index] and GH-Px level in the ALA group. The comparison of differences between FBG and IR at the beginning and at the end of study in the ALA treated group and the placebo group were also significant. This study supports the use of ALA as an antioxidant in the care of diabetic patients

[Comparison of the effect of low-glycemic index versus low-fat diet on the body weight and plasma lipid profile in obeses women]

The rate of carbohydrate absorption after a meal, as quantified by glycemic index, has an effect on postprandial hormonal and metabolic response. The aim of the present study is to determine the effects of low-glycemic index diet, versus low-fat diet on the body weight, BMI, WHR [waist/hip ratio] and plasma lipid profile of obese patients. A randomized controlled trial compared the effect of two dietary treatments [low glycemic index and low fat] in 46 adults, ages 18 to 55 years old, BMI >27, who proceeded to Motahary Clinic in Shiraz, Iran. Body weight, BMI, WHR [waist/hip ratio], fast and post-prandial Plasma lipid profile [Triacylglycerol, total Cholesterol, LDL-C, HDL-C concentration] level of obese women were measured at the beginning and end of 6 weeks. Changes in Body weight, BMI, WHR [waist/hip ratio] and Plasma lipid profile [Triacylglycerol, total Cholesterol, LDL-C, HDL-C concentration] were significant in both dietary groups. But no significant differences were observed in any parameter measured between two groups, except for the post-prandial HDL-C in which significant difference were observed. From these findings, it can be concluded that the isolated bacterial strain can utilize Organ phosphorus pesticides as a source of carbon and phosphorus. Utilization of these compounds by soil microorganisms is a crucial phenomenon by which these compounds are removed from the environment, thus, preventing environmental pollution. Both diets can equally be effective in decreasing the body weight and Plasma lipid profile

Efficacy of triple therapy with interferon alpha-2b, ribavirin and amantadine in the treatment of naive patients with chronic hepatitis C

There is controversy about the efficacy of amantadine in the treatment of chronic hepatitis C. In this study, we evaluated the efficacy of triple therapy with interferon-alpha, ribavirin and amantadine in the treatment of naive patients with chronic hepatitis C. Forty-eight patients with genotype 3 chronic hepatitis C received a three-drug regimen: interferon alpha-2b, 3 million units, three times a week, ribavirin 1000-1200 mg based on body weight, daily, in divided doses, and amantadine 100 mg twice daily, for six months. End of treatment response [ETR], sustained virologic response [SVR], biochemical response and histologic improvement were evaluated. Forty-eight patients, 41 male and 7 female, with a mean age of 37.42 +/- 16.2 years, were enrolled in the study. During treatment, four patients were excluded from the study due to severe thrombocytopenia, major depression and incompliance. End of treatment response was seen in 38 [86.36%] patients. Among these patients, 34 [77.27%] had sustained virologic response 6 months after the end of treatment and 40 [91%] had improvement in serum level of liver enzyme. Among patients who had response to treatment, liver biopsy was performed for 33 at the end of treatment and 31 patients had histologic improvement. Five non-responsive patients underwent liver biopsy at the end of treatment, and 2 of them had histologic improvement. No major side effects due to amantadine occurred in our patients. Triple therapy with interferon-alpha-2b, ribavirin and amantadine is a safe and effective regimen in the treatment of chronic hepatitis C