Functional Carbon Nanomaterials for Chemosensing and Therapeutic Application

Abstract

The thesis entitled, “Functional Carbon Nanomaterial for Chemosensing and Therapeutic Application” is an embodiment of investigations aimed at development of simple easy synthetic methodologies for N-doped carbon quantum nanomaterials for specific applications. The thesis has been divided into seven chapters.
Proper selection of molecular precursors and surface passivating agents can produce N-doped carbon nanomaterials with high QY, biocompatibility, and long-term stability which may offer a wide variety of applications. For surface modification of nanocarbon, the functional sites on the surface can react with the terminal groups of organic, polymeric, inorganic or biological materials via covalent, electrostatic interactions or hydrogen bonds. The resulting conjugates of nanocarbon can combine both of their properties, which makes it possible for them to be applied in targeting-specific sensing, drug delivery and bioimaging. However, the number of reactive groups capping the surface, the ratio of reactive groups and the coupling molecules are hard to control which makes surface engineering process inaccessible. Therefore, development of rational surface modification strategies in nanocarbons and related biomedical applications are under continuous progress.

In chapter 2, hydrophilic functional carbon quantum dots (CQD) have been prepared following hydrothermal method. This CQD is utilized for flumioxazin pesticide detection following Cu catalyzed azide-alkyne click reaction. The same CQD is conjugated with γFe2O3-DMSA for selective detection as well as removal of mercury from contaminated water sample in chapter 3. This can also facilitate imaging and sensing in bacteria and living fish organs. In chapter 4, therapeutic CQD has been derived from papaya leaf which shows photothermal antimicrobial effect under exposure of NIR laser. These CQDs are incorporated in polyvinyl alcohol-melamine hydrogel and has shown NIR stimulated photothermal and photodynamic effect. In chapter 5, Nitrogen doped mesoporous carbon spheres (NMCS) have been prepared from pyrrole and substituted aniline following soft templating approach. The effect of molecular precursors on size, microstructure and phototherapeutic properties has been investigated in detail. In chapter
6, NMCS gated with a light sensitive supramolecular gate has been designed which can carry anticancer drug gemcitabine. Photothermal and photodynamic property of these NMCS has been investigated under 980 nm NIR laser irradiation. Cell killing efficacy due to combinatorial photo-chemo therapy is investigated in oral cancer FaDu and skin cancer B16F10 melanoma cell lines. Polymeric coating over NMCS surface avoids premature leakage in vitro. The utilization of upconverted radiation by substituted nitrobenzyl linker tend to decomposition followed by drug release under momentary laser irradiation has been studied in vitro. The photothermal conversion efficiency and quantum yield of ROS generation has been investigated for these NMCS. Overall multifunctional NMCS provide a justified platform for cancer treatment.