Master of Science

thesisOver the past four decades, Multielectrode Array (MEA) devices have played a major role in electrophysiology by providing a simpler solution to simultaneous multi-site chronic extracellular recording: in vivo and in vitro. While a wide range of devices have been developed, almost all of them are limited to culturing and recording from one cell type, in vitro; and tissue surfaces, in vivo and in vitro. Most tissues are formed by different cell types that interact to maintain tissue function, like the heart which is composed mainly of cardio-myocytes and fibroblasts. Direct recording from such organs usually employs plunge-type electrodes which induce tissue damage and require better handling for sustenance. To better understand the functioning of such tissues, it is imperative to utilize recording systems that allow interactions between two or more cell types and at the same time sustain cultures with controlled cell number and distribution. In this thesis, the design, fabrication process, and characterization of an MEA device called the PerFlexMEA (Perforated Flexible MEA) is presented. It enables the generation and sustenance of a preparation with two cell types while recording their electrical activity. PerFlexMEA was developed using a thin (9?m) perforated Polycarbonate Track Etch (PCTE) membrane (3?m diam. pores, 200,000 pores/cm2) as substrate where cells can be cultured on both sides, allowing gap junction formation across the membrane via the pores. Cell number and distribution can be controlled on either side. The PerFlexMEA comprises a 4 × 5 array of square gold electrodes, each measuring 50 ?m × 50 ?m spaced 500 ?m apart. Parylene was patterned to insulate the leads (50 ?m thick) connecting the recording electrodes to the contact pads. A coinshaped device was designed to house the PerFlexMEA and to insulate its cell culture zone (wet) from contact pads (dry). Cardiomyocytes, isolated from neonatal mice were plated on the recording side of PerFlexMEA and electrical activity was recorded at a signal to noise ratio of 8.6 and peak to peak voltage of 200 ?V

THE WONDERS OF A MEDICINAL TREE: HOLOPTELEA INTEGRIFOLIA (ROXB.) PLANCH

In this busy era of herbal sciences, extensive study is being carried out on numerous plants to find novel drugs among which Holoptelea integrifolia Roxb. (Indian Elm) tree is just one of them. The age old knowledge ethnopharmacological significance, especially the stem, bark and leaves is well recognized in several Siddha, Ayurvedic, Unani literature. The plant parts are extensively used for its astringent, anti-inflammatory, digestive, carminative, laxative, depurative and diuretic properties. This plant is bestowed with a plethora of curative principles, namely antiviral, antimicrobial, antifungal, anti-arthritic, antioxidant, wound healing, anti-helminthic, anti-diabetic, anti-diarrheal, antiulcer, antitumor, adaptogenic, analgesic, hepatoprotective, larvicidal activities. Phytochemical investigation confirms the presence of signature chemical constituents such as terpenoids, alkaloids, glycosides, carbohydrates, steroids, sterols, saponins, tannins, proteins and flavonoids. The Recent discovery of antibacterial nature of callus promises of the discovery of callus derived novel antibiotics and unique drugs. The present review sheds light on current research trends in Holoptelea integrifolia with a serious look at its diverse ethnomedical uses as well as its prospect

STUDIES ON GE-ON-INSULATOR MOSFETS USING METAL SOURCE/DRAIN CONTACTS FOR ANALOG/ MIXED SIGNAL APPLICATIONS

In this paper, we report the effect of source/drain metal contacts on the electrical behavior of GeOI MOSFETs. The band diagram and current-voltage characteristics of the MOSFET are obtained using SILVACOATLAS, a 2D numerical device simulator, for various metals having a range of work function values. Our investigation reveals that the device using metals having a work function value more than 5 eV exhibits enhanced ON current, transconductance, intrinsic voltage gain, and also reduced subthreshold slope and OFF current

Doctor of Philosophy

DissertationWe have developed and tested new in vitro and in silico tools for studying gap junctions at the tissue and single channel level, respectively. We believe this work contributes toward expanding the field of gap junction within the available experimental and computational limits. The PerFlexMEA has the potential to be a potent tool for electrophysiological studies in fibrotic and arrhythmic cardiac tissues. Our in silico studies have revealed a new physiological mechanism that needs to be further investigated in vitro