Luminescent Heteroatom doped Carbon Quantum Dots for Sensing and Drug Delivery Applications

The present dissertation entitled, “Luminescent Heteroatom doped Carbon Quantum Dots for Sensing and Drug Delivery Applications” is an embodiment of the investigations aimed at developing simple inexpensive synthetic methodologies for producing heteroatom doped carbon quantum dots pertinent for sensing and biomedical application. The diagnostic and therapeutic applications of these multifunctional nanomaterials have been studied in vitro. The thesis has been divided into seven chapters. Hydrophilic boronic acid modified nitrogen sulphur doped carbon quantum dots (BNSCQD) have been prepared following a cost effective hydrothermal approach. The co-doping is aimed to improve the luminescence as well as targeting affinity of the CQD. Due to intense fluorescence property, appreciable photostability, boronic acid functionality and low cytotoxicity the carbon quantum dots (CQD) have been utilised in sensing glucosamine and cancer cell receptor Sialyl Lewisa (SLa). This method is highly sensitive and selective for visual detection of glucosamine sensing using a paper based sensor strip. Furthermore, integration of dopamine with BNSCQD (BNSCQD-Dopa) sets a platform for development of a fluorescence turn-on nanoprobe for fluoride detection in real samples. Due to boron’s affinity towards fluorine, the system was very selective towards fluoride when compared with other anions with a detection limit 0.7 pM. The practical ultrasensitive utility of the sensor is well demonstrated in human serum samples and also extended for fluoride detection in cellular environment. Further, the BNSCQD has been integrated with gadolinium iron oxide and mesoporous silica to construct a theranostic nanoparticle where BNSCQD imparts multiple functions such as simultaneous pH-sensitive gate opening, leading to control drug release, optical imaging, and receptor targeted internalization of the theranostic particle. The drug release experiment under variable pH and in the presence of competitive binding ligand SLa clearly shows the excellent responsiveness of the BNSCQD capped MSN hybrid system toward dual stimuli. Because of reasonably good r1 r2 relaxivities of the magnetic core and excellent fluorescence property of the doped carbon quantum dot, the hybrid can be utilized to monitor the therapeutic response through MRI and/or fluorescence imaging. Nitrogen doped mesoporous hollow carbon nanospheres (NCQD-HCS) have been prepared by inert calcination of polymer synthesized using pyrrole, aniline and Triton X-100 as molecular precursors. Here a direct synthetic approach is followed to yield high surface area carbon spheres with fluorescence property. An optimization of both surface area and photoluminescence is achieved by tuning temperature of calcination. The highest PL quantum yield of 14.6% is recorded, which is suitable for confocal imaging of cells. The fluorescence property of these spheres is attributed to the embedded nitrogen doped carbon quantum dots (NCQD) in carbon matrix. The photothermal property of NCQD-HCS has been investigated under 980 nm NIR irradiation. Cell killing efficacy of hollow spheres by photothermal ablation effect is evaluated in FaDu cells (oral cancer) as a modal cell line. Similarly, the upconversion property of carbon spheres is explored for light responsive drug release of gemcitabine. A highly biocompatible click chemistry based gating system is designed to restrict the premature release of drug molecules from porous nanospheres. The utilization of upconverted radiation by substituted nitrobenzyl linker, initiating its cleavage followed by drug release under periodic irradiation (980 nm laser) intervals has been tested in vitro. These fluorescent multifunctional nanoparticles provide a platform for combinatorial therapy of oral cancer

Study of multi-objective optimization and its implementation using NSGA-II

This project investigates the Multi-objective optimization strategies and their solutions using Multi-objective evolutionary algorithms (MOEAs). Multi-objective evolutionary algorithms (MOEAs) that use non-dominated sorting and sharing are criticized mainly for their; a) computational complexity, b) lack of elitism, c) need for specifying sharing parameter. In this paper the Non- Dominated Sorting Genetic Algorithm (NSGA) is studied and NSGA-II as proposed by Deb et. al. has been implemented, which alleviates the above three difficulties. In this study different objectives have been considered with different variables and constraints. The algorithm yielded satisfactory simulation results in all the different cases. The effect of the genetic parameters on the Pareto-Optimal front in all the cases has been studied. The results show that NSGA-II find much better spread of solutions and better convergence near the true pareto optimal front compared to other elitist MOEAs

Post-Covid Challenges and Opportunities for Higher Education

All over the world, the Covid-19 pandemic has had a big impact on the higher education sector. It has also put a lot of pressure on the Indian system of higher education. As a result, all academic institutions and colleges now teach their students through online platforms, thus forcing the higher education sector of the country to move its base online. The present crisis should be used as an opportunity to devise new ways to improve education that everyone can use and understand. Many new types of learning, new ideas, and recent trends have resulted from the pandemic. As we move forward, the same may happen

Topology of quadrupolar Berry phase of a Qutrit

We examine Berry phase pertaining to purely quadrupolar state ($\langle \psi | \vec{S} | \psi \rangle = 0$) of a spin-$1$ system. Using the Majorana stellar representation of these states, we provide a visualization for the topological (zero or $\pi$) nature of such quadrupolar Berry phase. We demonstrates that the $\pi$ Berry phase of quadrupolar state is induced by the Majorana stars collectively tracing out a closed path (a great circle) by exchanging their respective positions on the Bloch sphere. We also analyse the problem from the perspective of dynamics where a state from the quadrupolar subspace is subjected to a static magnetic field. We show that time evolution generated by such Hamiltonian restricts the states to the quadrupolar subspace itself thereby producing a geometric phase (of the Aharonov-Anandan type) quantized to zero or $\pi$. A global unitary transformation which maps the quadrupolar subspace to the subspace of purely real states proves a natural way of understanding the topological character of this subspace and its connection to the anti-unitary symmetries.Comment: 10 pages, 3 figure

Interaction Between Motor Domains Can Explain the Complex Dynamics of Heterodimeric Kinesins

Motor proteins are active enzyme molecules that play a crucial role in many biological processes. They transform the chemical energy into the mechanical work and move unidirectionally along rigid cytoskeleton filaments. Single-molecule experiments suggest that motor proteins, consisting of two motor domains, move in a hand-over-hand mechanism when each subunit changes between trailing and leading positions in alternating steps, and these subunits do not interact with each other. However, recent experiments on heterodimeric kinesins suggest that the motion of motor domains is not independent, but rather strongly coupled and coordinated, although the mechanism of these interactions are not known. We propose a simple discrete stochastic model to describe the dynamics of homodimeric and heterodimeric two-headed motor proteins. It is argued that interactions between motor domains modify free energy landscapes of each motor subunit, and motor proteins still move via the hand-over-hand mechanism but with different transitions rates. Our calculations of biophysical properties agree with experimental observations. Several ways to test the theoretical model are proposed.Comment: To appear in New J. Phy

Water filtration using nonwoven cartridge filter system

A cartridge based fibrous filtration system has been designed and investigated. For the fibrous medium, needle-punch nonwoven structure has been selected and different nonwoven samples are analysed for the water purification. A series of different needle-punched nonwovens made of polypropylene have been produced by changing mass per unit area, needling density and fibre linear density. A chemical oxygen demand test has been employed to obtain the filtration efficiency (FE). The FE obtained for these samples ranges from 8.84% to 78.04% in purifying the reference water (mud water). It has been found that the FE increases with increase in mass per unit area and needling density (p < 0.01). Also, the filter media made of finer fibres displays higher FE than coarser fibre (p < 0.01). On examining the filter performance in multiple filtration cycles, it is found that the FE increases initially and finally reaches to a saturation value. A good correlation (r2 > 0.95) has been found for the FE of each cycle with the air permeability, thickness and weight density of the loaded filter. The FE of the bare nonwoven (maximum FE) further improves (95%) by incorporating activated particles

Water filtration using nonwoven cartridge filter system

72-79A cartridge based fibrous filtration system has been designed and investigated. For the fibrous medium, needle-punch nonwoven structure has been selected and different nonwoven samples are analysed for the water purification. A series of different needle-punched nonwovens made of polypropylene have been produced by changing mass per unit area, needling density and fibre linear density. A chemical oxygen demand test has been employed to obtain the filtration efficiency (FE). The FE obtained for these samples ranges from 8.84% to 78.04% in purifying the reference water (mud water). It has been found that the FE increases with increase in mass per unit area and needling density (p r2 > 0.95) has been found for the FE of each cycle with the air permeability, thickness and weight density of the loaded filter. The FE of the bare nonwoven (maximum FE) further improves (95%) by incorporating activated particles

Atmospheric Cold Plasma: A Brief Journey and Therapeutic Applications from Wound Healing to Cancer Biology

Cold Atmospheric Plasma (CAP) has now become a well-known new edge technology in the field of biomedical science to agriculture and food technology. Ionized gas known as cold atmospheric plasma has recently been the subject of intense inquiry by scientists for its potential application for treatment in oncology and dentistry. Air, Helium, Argon, Nitrogen, and other gases can all be used to create Cold Atmospheric Plasma. Cold plasma can effectively and safely inactivate spores, bacteria, fungi, viruses, and small molecules and thereby improving wound healing, combating microbial infections, and treating skin conditions with great efficiency. Interestingly the in vitro and in vivo demonstration of CAP has shown promising applications in cancer healing and treatment. The most widely employed technique for producing and sustaining a low-temperature plasma for use in technological and scientific applications involves applying an electric field to a neutral gas. The non-equilibrium atmospheric pressure plasma jet (NAPPJ) and the dielectric barrier discharge (DBD) have both been widely used in biomedical applications. This review aims to evaluate the emerging plasma technology - the basic science, technical aspects and provide insights of biomedical application in diverse area

Phytochemical Investigation and Evaluation of Antibacterial Activity of Zizyphus Xylopyrus (Retz) Willd Leaf Extract

An experiment was carried out to evaluate the antibacterial activity of the Zizyphus xylopyrus ethanolic fractions, which was related to the phytoconstituents present. The plant's root powder was extracted using an ethanol extraction procedure that involved several consecutive steps. Following this, the extracted product displayed a distinct scent feature. Tannic acid, phenol, and flavonoids were found, indicating the existence of the required phytochemicals. The flavonoids were isolated using spectroscopic characterisation using the ethanolic extract. After then, this extract was used for additional pharmacological testing because in the study, only ethanolic extracts and saponins were used. Based on each sample's results from a variety of qualitative tests, this analysis was carried out. The discovery of new illnesses, especially those brought on by Enterococcus and Staphylococcus species, has sparked increased interest in the study of therapeutic plants in recent decades. These microorganisms have become resistant to widely used antibiotics and are the cause of a considerable proportion of hospital-acquired illnesses. For example, S. aureus, which was once sensitive to a number of antibiotics, is now showing signs of resistance to several medication