Synthesis of novel Fe3O4 nanoparticles coated with carboxymethyl sago cellulose and conjugated with 5-fluorouracil for diagnosis and treatment of cancer
thesisposted on 20.03.2017 by Anand Kumar Veeramachineni
In order to distinguish essays and pre-prints from academic theses, we have a separate category. These are often much longer text based documents than a paper.
A novel multifunctional superparamagnetic iron oxide nanoparticles (SPIONs, chemically Fe3O4) conjugated with carboxymethyl sago cellulose, and 5-fluorouracil (Fe3O4-CMSC-5FU) was synthesized for the treatment and diagnosis of cancer. The nano size of conjugated nanoparticles restricts its entry only to cancer cells (because of its leaky vasculature) and the magnetic property of SPIONs, could localize the nanoparticle conjugate at the target area by applying external magnets. The CMSP conjugation in the nanoparticles helps in achieving pH dependent release. Ideally, the nanoparticle should show no release in the blood (pH 7.4) and selective release in cancer cells (pH 5.4). SPIONs generate heat upon exposure to laser lights, and this photothermic effect could be exploited to kill cancer cells. Also, SPIONs are an excellent contrasting agent and useful in identifying cancer cells by CT scan. The Fe3O4-CMSC-5FU nanoparticles were synthesized using the solvothermal method and chemical conjugation. The XRD pattern of these nanoparticles showed the crystalline nature of Fe3O4 and 5-FU. The conjugation of Fe3O4 nanoparticles to carboxymethyl sago cellulose (CMSC) was confirmed using EDX and FTIR. The presence of Fe3O4 in the nanoparticles is also evident from STEM. Elemental analysis of conjugate nanoparticles using FESEM indicated the presence of fluorine, which could confirm the presence of 5FU. In addition, TGA also confirms the loading of the drug into the SPIONs-CMSP conjugate nanoparticle. The drug loading efficiency of 5-FU was found to be 10 to 84% w/w. In vitro drug release study was conducted at 37º C using a dialysis membrane which contains nanoparticle complex and immersed in the release medium at different pH (5.4 and 7.2). Samples were collected at distinct intervals, and the amount of drug released were analyzed spectrophotometrically. The release of the drug was observed only at pH 5.4, which is relevant for cancer cells. Cytotoxicity and biocompatibility studies showed that the novel nanoparticle formulation is non-toxic towards healthy cells but destroys the cancer cells due to its pH-dependent release profile. In vivo, studies using mice model confirmed the efficiency of the nanoparticles in delivering 5-FU only to cancer cells. Further, the anticancer effect enhanced by hyperthermia, which kills cancer cells due to elevated temperature via external stimuli of SPIONs using laser light. The combination of hyperthermia and targeted delivery of 5-FU was observed efficient compared to the individual treatments. Targeted and controlled release of the drug from the proposed delivery vehicle along with photo-thermal therapy (hyperthermia) looks promising in selectively killing cancer cells. Also, these nanoparticles can act as useful CT imaging tools in diagnosing the tumor location and monitoring prognosis of the therapy. The focus of this work is to use multifunctional Fe3O4-CMSC-5FU nanoparticle conjugate for oncological applications, with emphasis on therapeutic, diagnostic and prognostic purposes. The results have exibited Fe3O4-CMSC-5FU can effectively be used as a controlled drug delivery system owing to effective magnetic site targetting property and cancer cell traget selection of the nanopartical system.