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Research

My current research interests mainly focus on (1) smart multifunctional hybrid nanomaterials and (2) applications of nanomaterials. For the former, my research aims to create novel hybrid nanomaterials based on metal, metal oxides and metal sulfides, dendrimers, upconversion nanomaterials and polymers with controlled morphology, attractive functionalities and targeted properties. For the latter, my research aims at the application of nanomaterials for drug delivery, biosensing, energy and catalysis whilst also investigating the formation mechanisms and process-structure-property relationships.  To achieve these goals, my research takes a holistic approach, encompassing the design, synthesis, functionalisation, characterisation and application of various types of nanomaterials. 

My research focuses on the development of nanomaterials for biomedical and environmental sustainability applications. A brief description of a few of my projects are mentioned below.

 

1. DESIGN OF FUNCTIONALIZED HYBRID METAL/METAL OXIDE NANOCOMPOSITES FOR ENHANCED THERAPEUTIC AND  BIO-IMAGING APPLICATIONS

The project involves the fabrication of multifunctional stimulus-responsive metal/metal oxide nanocomposites by hydrothermal methods. The nanocomposites are made multifunctional by the attachment of various molecules. Firstly, a hydrophilic drug and polymer combination are coated on the nanocomposite core in-situ. The nanocomposites are further coated with stimuli-responsive polymer, which can entrap another drug molecule, thereby exhibiting enhanced therapeutic efficiency. The polymers are chosen in a way so that they show stimuli responsiveness to pH, temperature, ultrasound or enzyme. Further, specificity to unhealthy cells in diseases such as cancer is also important in terms of therapy. To achieve specificity, the nanocomposites are further decorated with ligands which are over-expressed by the affected cells.

In this manner, the core of the nanoparticle (Cus, ZnS) imparts properties such as imaging (which becomes a diagnostic tool) or hyperthermia (enhanced therapeutic application); as the nanoparticle assembly carries two drugs, it becomes a dual drug carrier, and the coating of the temperature sensitive polymer makes the nanoparticle assembly stimulus-sensitive. Stimulus responsiveness, drug release studies and dual drug action are tested by studying drug release in the presence of a stimulus by evaluating the LD50 cellular degradation.

2. DEVELOPMENT OF UP-CONVERTED NANOPARTICLES (UCNPs) FOR DRUG DELIVERY AND CELLULAR IMAGING

This project involves designing of a mesoporous matrix for encapsulating the UCNPs and the therapeutic agent (drug). The synthesis of the UCNPs@mesoporous matrix are carried out to ensure flexibility in modulating the particle size, shape, doped ions, and emission profile of the nanoparticles. The photothermal effects for manipulating drug delivery by suitable laser are studied with respect to: (i) enhancing the quantum yield of the UCNPs; (ii) incorporation of photo‐responsive materials with red‐shifted absorptions into the UCNPs; and (iii) tuning the UCNPs excitation wavelength. The luminescence signal for bio-imaging is directed towards imaging-guided cancer therapy. Different types of polymeric/metal oxide nanoparticles are used to enhance the hydrophilicity and biocompatibility of the UCNPs.

The NIR‐initiated drug delivery systems is envisaged to offer a high degree of spatial and temporal therapeutic release and provide precise control over the released dosage. They are better than the conventional light‐based drug delivery systems since NIR offers better tissue penetration depth and a reduced risk of cellular photo‐damage caused by exposure to light at high‐energy wavelengths (e.g., ultraviolet light, <400 nm). The development of drug delivery systems that can be activated by low-intensity NIR illumination is highly desirable to avoid exposing living tissues to excessive heat that can limit the in vivo application.

3. DEVELOPMENT OF COST EFFECTIVE SUPERCAPACITORS BASED ON CONDUCTING POLYMERS AND METAL FERRITES

In this project, we have worked towards the fabrication of cost-effective nanocomposite electrodes based on metal ferrites, viz. manganese ferrites and polyaniline (PANI) that can be used simultaneously to carry mechanical loads (power) and at the same time store (and deliver) energy. The metal ferrites were synthesized using a hydrothermal method using low-cost metal salts as the starting material, while PANI was synthesized using chemical oxidative polymerization. The mechanistic interaction among the metal ferrites and PANI in the nanocomposite and their capacitive mechanism were investigated. Due to the synergistic effects of the ferrites and the polymer, the nanocomposite electrode led to extraordinary electrochemical performance, wherein the fluffy PANI provided channels for charge transport, and the ferrites stored the electrons through the change in the valence state of the active sites. Additionally, CuxMn(1-x)Fe2O4@PANI binder-free nanocomposite prototype was fabricated, which reduced the effort in the process of electrode fabrication and gave excellent electrochemical performances with high capacitance value and a high power density by restricting the contact resistance between the electrode and current collector. The fabricated symmetrical device based on the nanocomposites can be used as stable electrode material in ultra-high-rate energy storage technologies like batteries and supercapacitors.

4. FABRICATION OF DENDRIMER-MAGNETIC NANOPARTICLES BASED NANOBIOSENSOR FOR EARLY DETECTION OF LIVER CANCER

In this project, PAMAM dendrimer functionalized magnetic nanoparticles were chosen as signal enhancement materials for fabricating biosensor for detection of liver cancer. The nanoparticles helped to increase sensitivity of biosensor to specifically detect hepatocellular carcinoma (HCC) specific biomarkers. Since no single biomarker is unique for particular cancer detection, herein, a combination of two HCC-specific serum biomarkers; alpha-fetoprotein (AFP) and glypican-3 (GPC-3) were selected for simultaneous detection.  The detection was evaluated with respect to the electron-transfer reactions taking place near the electrode surface using electrochemical technique (cyclic voltammetry, differential pulse voltammetry and electrochemical impedance spectroscopy). The developed biosensor was also explored for their use in human serum samples, spiked with varying concentration of antigens.  The developed biosensing have the potential for clinical translation. Further, an ink-jet printing technique was used to demonstrate the applicability of proposed biosensor as a proof-of-concept for making future prototype device. The study concluded that the ink is printable and hence the biosensing strategy can be further miniaturised for chip-based detection.

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