RESEARCH INTEREST INTRODUCTION:

Transcription

1 RESEARCH INTEREST INTRODUCTION: Cancer is regarded as one among the dreadful diseases. Despite of much advancement in the theranostics of cancer, the cure rate for this terrible disease without any side effect is Gordian knot. As Surgery and radiation therapy may not possible at advanced stages of cancer, chemotherapy is most commonly preferred. Although the purpose of chemotherapy is to kill the tumor cells, still there is a need of development of carriers for alternative dosing with targeting efficacy and to prevent the drug from bio-degradation before reaches the target cells. However, most of the existing chemotherapeutic agents suffer with lack of selectivity, less solubility, shorter lifetime in blood stream and multi-drug resistance with the potential risk of side effects. In short, existing chemotherapeutic agents are anion in nature, which can bind with both normal and cancerous cells and this may cause lack of selectivity. Based on these, various targeted drug carriers have been developed to improve the existing therapeutic efficacy and also to prevent the drug from biodegradation before reaching the target cells, as well as to reduce the side effects. Recently, there is an emerging explosion in the development of nanomaterials based carriers for biolabeling, diagnostics and targeted drug delivery systems applications (DDS). The main purpose of targeted drug delivery methods is not only to deliver a biologically active compound in a controlled manner (time period and releasing rate) but also to maintain the drug level in the body within therapeutic window. This can be obtaining by the nanoparticles which are functionalized with the natural polymers helps in bioconjugation of drug molecules inside/ onto the surface of nanoparticles. The nanoparticles with dimensions less than 30 nm which can utilize the enhanced permeability and retention effect (EPR) in tumor sites to release even highly toxic drugs within the tumor cells with reduced side effect to the normal cells. A numerous counts of functionalized nanoparticles were already been synthesized and bio-conjugated with an anticancer drug for drug delivery system (DDS) applications. Still, the problem with the existing nanoparticles is it itself can cause the side effects due to the toxicity. Recent years, researchers had also given attention to Quantum dots and inorganic nanoparticles for the effective cellular imaging and it could be possible to track the nanoparticles

2 and their thermocokinetics by fluorescence studies and for targeted drug delivery applications. Even though it has numerous advantages in DDS, when interact with light, these particles may undergoes photo-bleaching. By considering the above factors and drawbacks of existing nano bio-particles, the need of less toxic nanoparticles such as rare earth lanthanide doped nanoparticles (Tb, Ce, Eu, Yb, Tm, Gd etc), bifunctional (magnetite-rare earth doped) nanoparticles, albumin nanoparticles possess more attention in cancer diagnosis, chemotherapy and chemo-radio therapy respectively. Still these particles were very rarely been investigated for targeting drug delivery. In this context, rare earth doped nanoparticles have been considered for modulating the targeted dosage of drug due to its ease of synthesis, photo stability, sharp emission spectra and large stokes shift with longer emission lifetimes (µs to ms) when compared to other fluorescent dyes. Based on these, my previous work was focused to study the following objectives: The synthesis and characterization of various rare earth fluoride doped nanoparticles. The nanoparticles characterization was made using various spectroscopy and microscopy for the particle size confirmation, surface charge before and after bioconjugation and optical properties of synthesized nanoparticles. Characterization and bioconjugation of synthesized nanoparticles with chemotherapeutic drugs, 5-Fluorouracil (5FU), Methotrexate (MTX), Paclitaxel (PTX), Cisplatin and Ace semi (4-[(1-(2-carbamothioylhydrazinylidene) ethyl] phenyl acetate) and their interactions using photo physical techniques. UV-Visible spectrophotometer was used in my research work for absorption spectra, percentage yield, entrapment efficiency, number of drug molecules attached per nanoparticles, maximum adsorption of drug onto /within the nanoparticles surface and invitro drug release kinetics of drug from nanoparticles. The adsorption and release percentage shows better results when compare with that of previously reported nanoparticles.

3 Studies on the Drug conjugated nanoparticles and their binding mechanism with model protein and DNA model such as Human and bovine Serum Albumin (HSA &BSA) and calf thymus Deoxyribo nucleic acid (ct-dna) by optical spectroscopic techniques. The cytotoxic effects of the drug conjugated nanoparticles against MCF-7 breast cancer cell lines and A549 lung cancer cell lines were carried out using invitro cytotoxic assay, MTT assay, Hoechst staining method and fluorescence apoptosis method. The broad area of my research involves in synthesis and characterization of various biocompatible and less toxic nanoparticles for cancer diagnosis and therapeutical applications. I have also been involved in formulation and bioconjugation of nanoparticles with anticancer drugs such as 5-Fluorouracil, Methotrexate, Paclitaxel and thiosemi carbazone derivatives for targeting drug delivery mechanism. The confirmation of drug conjugation with the nanoparticles have been carried out using various physico-chemical techniques such as Transmission electron microscopy, Scanning electron microscopy, Spectrophotometer, Fluorescence spectroscopy, Time-resolved fluorescence spectroscopy and Micro Raman spectroscopy. The percentage yield and encapsulation efficacy of these nanoparticles have also been calculated, in order to know the effective dose. While designing and dealing with the biomedical applications of any nanoparticles, it is important to study the biosafety and effect of these nanoparticles inside our body using carriers- albumin (protein) and DNA model. Hence, the studies on the interactions between the protein and DNA models with drug-nanoparticles have also been carried out. Since, my research also deals with the therapeutical applications, i have also been involved in studying the efficacy of nano formulated drugs in breast and lung cancer cell lines for the confirmation of increased cell death using formulated drug conjugated nanoparticles compared with that of drugs (without nanoformulation) using fluorescence inverted microscopy. As we are also focusing on designing a cost effective nano-biosensors for DNA detection applications, at present, I am working with rare earth doped nanoparticles for effective detection of DNA in biological samples. In future, I want to extend my view from invitro studies of drug conjugated biocompatible nanoparticles to detailed invivo theranostic applications for targeted drug delivery. Although, we

4 are taking effort in designing nanoparticles for theranostic applications, It is important to design a cost effective DNA sensor for cancer detection applications using rare earth doped nanoparticles, to diagnose the cancer at initial stage to avoid the loss of soul worldwide. Future plan: For next 3 years, I plan to continue my research with synthesis, formulation and bioconjugation of various expensive anticancer drugs with rare earth fluoride doped nanoparticles (magic bullets) for targeted drug delivery applications. In general, Taxol and platin derivatives are most commonly used for various human cancers; however clinical trials of taxol and platin derivatives possess limited success due to its poor solubility, systemic toxicity, non-specific drug release and undesired side effects. To overcome these barriers, I plan to synthesize various less toxic rare earth fluoride doped nanoparticles based targeted drug carriers to get the highest percentage yield and entrapment efficacy with minimal drug concentration. The maximum adsorption and in-vitro drug release kinetics were obtained to get the maximum drug loading capability. This helps in eliminating the tumors with reduced toxicity, increased cancer cell specificity, biodegradable and good biocompatible properties. In addition to that, the invitro and invivo cytotoxic studies have to be carried out in lung (A549), breast (MCF-7), ovarian (A2780), cervical (hela) cancer cell lines and nude mice models for various carcinomas. I am very much eager to work with nanoparticles for radiation therapy, although some of the nanoparticles have the property of emitting radiation for a long time with higher efficacy, recently samarium and gadolinium also under investigation for radiation therapy. Many researchers were analyzed and reported about the gadolinium doped nanoparticles and its use as a MRI contrast agent, recent years hybrid Fe3O4/Gd2O3:Eu nanoparticles which has Fe3O4 core and a Gd2O3:Eu shell are fluorescent due to the presence of Eu3+ ions and magnetic due to the magnetite core, this helps as both contrast agent and also leads to therapy using magnetic core for brain tumor treatment. Recently, gadolinium-based nanoparticles have been developed for MRI contrast enhancement and multimodal imaging (MRI and fluorescence or X-ray) or therapy by thermal neutron irradiation. The use of nanoparticles leads to longer rotational correlation times which increase the proton relaxivity (defined as the modification of the inverse proton relaxation time due to the presence of the contrast agent over the contrast agent concentration) and, with an adequate coating, to longer blood circulation times. In addition, Gd 3+ doped

5 nanoparticles can be used as a platform for grafting molecules allowing multimodal imaging and/or specific targeting in vivo. Gadolinium chelates were also used for the coating of gold nanoparticles to combine X-ray and MR imaging. The use of Au doped DTDTPA-Gd nanoparticles which increase the contrast in both MRI and X-ray computed tomography (CT) was already been reported. Gold nanoparticles are indeed known to be good contrast agents for CT, and this effect is enhanced by the Gd-chelate coating. These nanoparticles are thus already good candidates for medical use. My aim is to use this Gadolinium doped nanoparticles for MR guided Radiation therapy by coating the Gd3+ with ytterbium, gold and europium nanoparticles. Next, I have a plan to prepare a nanoparticles modified carbon paste electrode (CPE) sensors to detect the DNA (Deoxyribo Nucleic Acid) in bio-fluids such as blood, plasma, saliva and urine samples for cancer diagnosis. The modified electrode matrixes have to be constructed with the mixture of nanoparticles (which has the tendency and improved efficacy in DNA detection), graphite powder and mineral oil. The ability of the as-prepared electrodes have been analyze for the DNA detection efficacy. The different known concentrations of commercial DNA such as hs-dna and ct-dna are analyze at first to get the detection percentage of DNA using nanoparticles. In this work cyclic voltammeter, Fluorescence spectroscopy and Raman spectroscopy were used to find whether the nanoparticles can detect the different concentrations of DNA. The interleukin 6,8 receptors interaction with nanoparticles are also detect externally using chemical method and analyze the same in cancer biosamples (Interleukin- 6, 8 receptors are produced inside the body wherever there is an inflammatory situations such as trauma, burns and cancers. In general, Fluorescence and Raman Spectroscopy are very sensitive optical methods for biosamples detection. Hence, I had decided to use the same for the characterization of nanoparticle based electrodes. Contribution to Science: The main aim of my research is to develop nanocarriers for targeting drug delivery applications from Lab bench to bedside route. The early research done by me in laboratory constitutes nanodrug bio-conjugation, bio-formulations and development respectively. In early stage, generally the scientists and researchers search for the complications of FDA approved drugs while possess during clinical trials. My research also focuses on the complications and side effects of those drugs, and overcome the effects by means of reformulation with less/ non toxic

6 nanoparticles to improve the targeting ability of drugs inside the body without any side effects. The nanoparticles thus formulated and apt for drug conjugation / modified drug development should not affect by various factors such as decompose or decay before reaches the target of interest, should not produce any adverse effects/toxicity to normal cells, etc,. By keeping this in mind, the invitro cell viability and cytotoxic studies has been carried out to evaluate the effects of nano formulated drugs in breast and lung cancer cell lines. The cell lines studies results shows that increased effects of nano-formulated drugs in cancer cells without affecting the normal cells. The adsorption and release of these drugs from nanoparticles are higher in cancer cells than that of normal cells, due to the absence/ deformation of mitochondria in cancer cells. From the detailed study, the drugs which I formulated are not only biocompatible but also ensure the patients should receive safe and effective medicines. In order to contribute to science and society, these formulated drug nano carriers have to be progress to preclinical testing such as elaborate laboratory and animal test that will ensure the safety for testing in humans. The medicine thus used for testing will be in progressive phases of clinical trials to gather the information about the safety and efficacy need to get FDA approval. In addition to that, I want to use the rare earth doped hybrid nanoparticles for radiation therapy in order to reduce the radiation dosage with improved cure rate in initial stages of cancer.in short, the foremost focus of my research is to develop, design and contribute various targeting nanocarriers for anticancer drugs in order to eradicate the risks for the patients to be treated. My research will helps the common people also get the effective/ reformulated medicines and this may leads to enhanced cure rate of the dreadful diseases like cancer.