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.

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.