User:Farnaz Rezaei (UU)

Controlled release of anticancer drugs
Nanoparticles are defined as particulate dispersions or solid particles with a size in the range of 1–1,000 nm. Graphene oxide nanosheet (GOns) was synthesized by Hummers method. Graphene oxide(GO) is produced by introducing graphite to oxidation agents that add oxygenated functionalities to the graphite structure and exfoliates the layers, thereby improving its dispersion in water. Recently, GO has emerged as one of the most attractive nanofiller in polymer nanocomposite technology due to the notable improvement and enhancement of mechanical, thermal, and electrical properties of many nanocomposites, improvements that could lead to innovative solutions for many applications Graphene oxide (GO), an oxidative derivative of graphene, has attracted extensive interests in drug delivery because of its water solubility and ultra-high surface area available for efficient drug loading. However, GO suffers from aggregation and is negatively charged, which severely compromises its application in loading anticancer drugs and genes. Further, modification of GO is therefore needed. Natural hydrophilic polymers including dextran, cyclodextrin and chitosan have been widely used to modify GO to decrease its aggregation. Human serum albumin (HSA) is the most abundant protein for approximately 50% of the proteins in human plasma. The study of HSA as a model protein is important in biology, medicine, bio-technology, food and others areas. Human serum albumin (HSA) is a highly water-soluble globular monomeric plasma protein with a relative molecular weight of 67 KDa, consisting of 585 amino acid residues, one sulfhydryl group and 17 disulfide bridges. Among nanoparticulate carriers, HSA nanoparticles have long been the center of attentions in the pharmaceutical industry due to their ability to bind to various drug molecules, great stability during storage and in vivo usage, no toxicity and antigenicity, biodegradability, reproducibility, scale up of the production process and a better control over release properties. In addition, significant amounts of drug can be incorporated into the particle matrix because of the large number of drug binding sites on the albumin molecule. It has been proven that nanocomposite of graphene oxide nanosheets with identical surface area and HSA nanoparticles could be improve the drug delivery properties. So that, in this study, the graphene oxide and HSA nanoparticles have been prepared. The structural properties of the nanocomposite were characterized by UV-Vis spectroscopy, Fourier transform infrared spectroscopy (FT-IR) and field emission scanning electron microscopy (FE-SEM).

Preparation of graphene oxide nanosheets (GOns)
GO was synthesized from natural graphite via peroxidation / thermal expansion of graphite followed by modified Hummer’s method. Graphite powder (0.5 g) was first added to 24 ml of concentrated sulfuric acid under temperature of 0 ˚C (in ice bath) and was stirred for 15 min and then 3 g of KMnO4 was added to the mixture. The reactor was then transferred to a 40 ˚C bath and was completely stirred under that condition for 24 h. 100 ml water was then added to the system and the mixture was stirred in ambient temperature 3 ml H2O2 was added under slow stirring until the color of the solution changed to yellow form dark brown. To eliminate metal ions, the solution was washed with 100 ml of HCl. The solution was then washed with water until the pH reaches 7.0.

Characterization of GO
GO produced through exfoliation of graphite oxide created from a modified Hummers method, was characterized by UV-Vis, FT-IR and SEM to confirm the dimensions of the GO, chemical bonds present and the interlayer spacing, respectively. Four main groups can be noted on the FT-IR spectra, at 1053 cm1 for C–O bonds; at 1225 cm-1 for C-O-C bonds; at 1624 cm-1 for C = C bonds; at 1733 cm-1for C = O bonds and at 3401 cm-1 for O–H bonds from retained free water in the sample.

Characterization of nanocomposites
HSA-GO nanocomposites was created by dispersing known quantities of GO in HSA solution. Characterization of the nanocomposites will allow for an analysis of the interfacial interactions, the GO dispersion and the crystallinity of the nanocomposites.