Hybrid Theranostic Platforms for Cancer Nanomedical Treatment

  • Khachatur Julfakyan

Student thesis: Doctoral Thesis

Abstract

Cancer is a leading case of mortality worldwide. Governments spent multibillion expenses on treatment and palliative care of diseased people. Despite these generous funding and intensive research with aim to find a cure or efficient treatment for cancer, until now there is a lack in selective cancer management strategies. Conventional treatment strategies for cancer, such as surgery, cytotoxic chemotherapy, radiation therapy, hormone therapy don’t have selectivity toward cancer – the property of discrimination of healthy organs and tissues from the diseased site. Chemotherapy is very challenging as the difference between effective and lethal doses is very minuscule in most cases. Moreover, devastating side effects dramatically changes the quality of life for cancer patients. To address these issues two main strategies are intensively utilized in chemistry: (I) the design and synthesis of novel anticancer organic compounds with higher selectivity and low toxicity profiles and the second, design and preparation of biocompatible nanocarriers for imaging and anticancer compound selective delivery nanomedicine. The following dissertation combines the above two strategies as bellows: First project is related to the design and synthetic route development toward novel nature-inspired group of heterocyclic compounds – iso-Phidianidines. The second project focused on design, preparation and evaluation of hybrid theranostics (therapeutic and diagnostic in a single entity). Chapter 1 is a general background review of the major topics that will be discussed in this dissertation. The first efficient and high-yielding synthetic route toward iso-phidianidines, containing regioisomeric form of 1,2,4-oxadiazole linked to the indole via methylene bridge is reported in Chapter 2. In vitro test of the synthesized library of iso-phidianidines revealed micromolar range of cytotoxicity toward human cervical cancer cell line. Structure activity relationship revealed the importance of presence of monosubsituted amine in 3 position of oxadiazole to maintain activity. Moreover, gradual increase of activity was detected in increasing of the length of the diamine. Polyamine (spermidine) side chain demonstrated strongest anticancer activity, identified as lead compound and may be studied further as a good candidate for cervical cancer treatment. Finally, the remaining high activity of amino-terminated iso-phidianidines demonstrated that presence of guanidine group in termini is not necessary for high cytotoxicity. The second part of this dissertation (Chapter 3) discusses the rational design, wet protocol synthesis and complete characterization of the novel hybrid material – polydopamine coated iron-cobalt nanocubes (PDFCs). This material was loaded with anticancer model drug doxorubicin in one step procedure (PDFC-DOX) and the resulting drug-delivery vehicle was found to be successfully internalized by cervical cancer cells. The cytotoxicity test demonstrated inhibition of 50% of the cells at the concentration of 30μg/ml for PDFC-DOX. Moreover, the release was highly attenuated and pH-sensitive in acidic range. PDFC was also modified with fluorescein leading to green fluorescent nanoparticles PDFC-FITC, which demonstrated excellent intracellular molecular imaging property. PDFCs with one of the highest magnetic saturation among the materials used in biomedicine (226 emu/g based on core) showed the absence of any cytotoxicity in vitro and excellent MRI contrasting property (r2=186.44 mMs-1, higher than commercial contrast agents Ferridex® and Clio®), both in vitro and in vivo on mice. They were cleared out from the mice bodies in month without affecting their health. Due to the high density of core (8.3 g/cm3) they demonstrated ability to be contrast materials also for X-Ray CT diagnostic modality, increasing the tumor detection and visualization probability in combination with MRI. In addition to it’s diagnostic and drug-delivery modalities, PDFC was evaluated also for microwave-induced cytotoxicity as a novel concept in cancer treatment. As low as 10 μg/ml concentration of PDFCs in human cervical cancer cells caused extensive death above 73% upon exposure to 2,45 GHz of microwaves for one minute. Laser irradiation (808 nm, 15 minutes) of cancer cells with internalized PDFCs caused cell death above 60%. The specific absorption rate of PDFCs at 470 MHz frequency and 20 mT of the alternating magnetic field power was 180 W/g, which is nearly 100 W higher than for commercial nanoparticles (Ferridex®).
Date of AwardOct 2015
Original languageEnglish
Awarding Institution
  • Physical Science and Engineering
SupervisorNiveen Khashab (Supervisor)

Keywords

  • iron-cobalt nanoparticles
  • polydopamine
  • Nanomedicine
  • Theranostics
  • cancer
  • one-for-all

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