Materials Engineering (MatEng)
https://etd.iisc.ac.in/handle/2005/42
2024-03-29T12:38:22ZAging Response And Its Effect On Mechanical Properties Of Cu-Al-Ni Single Crystal Shape Memory Alloy
https://etd.iisc.ac.in/handle/2005/1294
Aging Response And Its Effect On Mechanical Properties Of Cu-Al-Ni Single Crystal Shape Memory Alloy
Suresh, N
2011-07-15T00:00:00ZApplication of Mesoporous Silica nanoparticles as a nano-carrier for the treatment of HCV and HIV infections
https://etd.iisc.ac.in/handle/2005/4964
Application of Mesoporous Silica nanoparticles as a nano-carrier for the treatment of HCV and HIV infections
Mukherjee, Mousumi Beto
Carrier-mediated drug delivery systems have emerged as a powerful tool for the treatment of various diseases, especially, in the field of viral infection. The therapeutic index of traditional and novel anti-virals are heightened through the enhancement in their target specificity. Anti-virals can be delivered at the targeted site without any degradation with the support of a nano-carrier. Viral disease treatment needs an upgraded drug delivery system to reduce the dosage and systemic toxic effects along with improved pharmacokinetic properties of anti-viral therapeutics.
In this thesis, mesoporous silica nanoparticle (MSN) based delivery system was synthesized to deliver therapeutic agents to increase their efficiency and bioavailability. Functionalization was carried as per the requirement. The synthesized delivery vector was characterized using different techniques. The ability of MSN to interact with therapeutic agents was also evaluated. Toxicity studies using cell cultures and animal models assured the non-toxic properties of this delivery vector. The as prepared nanocarrier was able to mediate efficient transfection in mammalian cells. Preferential delivery of drugs was proven using both in vitro as well as in vivo models confirming the target-specific nature of this MSN based delivery system.
Targeted delivery of small hairpin DNA (shDNA) to liver using MSN based nano-carrier to combat hepatitis C virus (HCV) infection was investigated. MSN was amine functionalized to achieve electrostatic interaction between the nanoparticle and DNA. Galactose functionalization ensured the preferential delivery to the liver through the ligand asialoglycoprotein receptor interaction abundantly present on liver cell surface which was visualized in the in vivo model. Significant reduction (about 94 %) of viral RNA level was achieved which confirmed the successful delivery and action of the shDNA.
Target specific property of as-synthesized nanoparticle was further expanded in delivering the two herbal compounds Phyllanthin and Corilagin in HCV infection. These herbal compounds were derived from natural source Phyllanthus amarus and shown to have hepatoprotective property. The delivery of herbal compound-nanoparticle complex to the HCV JFH-1 infectious virus systems resulted in ~93% decrease in viral RNA level which was 3-fold higher than free Phyllanthin or Corilagin.
Further this MSN based nano-carrier was used to enhance the bioavailability of retro-viral drugs. Here in this work MSN was coated with chitosan to inhibit the premature release of drugs and increase the cellular uptake. The amount of drug loaded in MSN was found to be 76.91 %. On applying the drug loaded nanocarrier in Balb/c mice model a 2.4-fold increase in bioavailability was noted.
The work described in the present thesis presents a new MSN based delivery system which can act as an efficient nano-carrier both in gene delivery and drug delivery for virus infected diseases.
Architecting and Developing Sensors for Environmental Monitoring
https://etd.iisc.ac.in/handle/2005/5539
Architecting and Developing Sensors for Environmental Monitoring
Anil, Amith G
Pollution arising from inorganic and organic contaminants is a major environmental hazard that needs imperative attention. Anthropogenic and natural deposition of heavy metal ions constitute a significant component of this pollution. Selective, sensitive, and unambiguous detection of such pollutants is of prime importance in assessing environmental damage and controlling toxicity in biosystems. To this date, multifarious sensing systems and methodologies have been developed. Limited selectivity, sensitivity and environmental stability of these sensors continue to hinder their large-scale deployment. This works attempts to look at the problems of selectivity and sensitivity taking inspiration from natural processes like bioremediation and utilising data driven methods. Bioremediation is a potential, environmentally benign method for treating heavy metal polluted water. Bioremediation of hexavalent chromium, a carcinogenic pollutant, by Citrobacter freundii species of bacteria has been evaluated. Synchrotron based scanning transmission X-ray microscopy was utilised to analyse the process in an attempt to decipher the biosorption and bioreduction mechanism. Understanding this would assist in designing better selective sensors for Cr(VI). Bacteria derived carbon dots were synthesised from Citrobacter freundii bacterial cells following a green synthesis approach. The obtained carbon dots displayed fluorescence sensing with exceptional selectivity towards Cr(VI). The sensor performance and mechanism of Cr(VI) detection were thoroughly evaluated. In another work, a colorimetric sensor with high selectivity toward Cr(VI) was demonstrated and the sensor response was predicted using data driven methods. The computational method could simulate and predict sensor response at unknown concentrations in between known experimental concentrations. These predictions can generate sensor calibration scales with high accuracy, eliminating experimental and instrumental errors involved. Conjugated polymers have been studied as a potential class of materials for environmental sensors. Herein, the design, synthesis and sensing properties of a novel hexylthiophene conjugated polymer is reported for fluorescence detection of Fe(III) metal ions. Similarly, a nickel based organometallic complex was synthesised for detection of urea in real samples.
Architecting Conjugated Molecules for Band Gap Engineering & Photostability
https://etd.iisc.ac.in/handle/2005/5314
Architecting Conjugated Molecules for Band Gap Engineering & Photostability
Vinila, N V
Organic photovoltaic (OPV) modules are flexible, light weight, transparent and thin compared to other emerging photovoltaic technologies, making them well-suited for applications ranging from solar windows to fabrics. A large number of polymer semiconducting materials of Donor-Acceptor–Donor (D-A-D) architecture have been synthesized and used in OPV devices in recent times reaching remarkable power conversion efficiencies up to 13%. However, the diversity of monomeric units and the numerous available reports in the structural complexity of D-A-D conjugated p-type polymers indicate that there is scope for new materials which can further improve the performance of OPV devices based on D-A-D polymers.
The first part of the thesis explores structural level architecturing of conjugated small molecules and polymers to modify the properties of the OPVs. Molecular level modification could tailor the energy levels of the polymers, planarity and broadened the absorption spectra. Enhancement of the material properties led to improved device performance. Additional to the development in power conversion efficiency of the OPVs, the cost of large area OPV device manufacture continues to decrease with improvements in roll-to-roll manufacturing processes. However, while these advances in efficiency and cost will ultimately the key to the success of the technology, the long term stability of OPV devices under illumination still remains an obstacle to their industrial viability. While the thermal and oxidative-stability of contacts and interfaces in an OPV device can contribute to a decrease in its performance with time, a leading contributor to device decay is photo-oxidation of the active layer itself. Hence a series of chalcogen based polymers have been synthesized and the photostability of the unencapsulated active layers and the device life time has been monitored over a period of time. The results showed, changing of hetero atom could improve the photostability.
The thesis further investigated the photostability of several combinations of fluorinated and non-fluorinated high-performance donor polymers with both traditional and fluorinated fullerenes. The miscibility of the active layer component is probed with time-resolved photoluminescence (TRPL). These results are correlated with the photo conductance of the material. The miscibility of the polymers and the fluorinated fullerenes were improved by the strategic fluorination of the polymers, by new synthesis routes. These results ultimately suggest that appropriate fluorination strategies applied to both the donor and acceptor can be a viable route toward a new model of intrinsically photo- and phase-stable OPV active layers.