Development of non-invasive fiberglass probes

• Grant number: 17/16828-9
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• Start date: March 01, 2018
• End date: January 31, 2019
• Field of knowledge: Physical Sciences and Mathematics - Chemistry - Inorganic Chemistry
• Principal Investigator: Younes Messaddeq
• Grantee: Kishore Kumar Devarepally
• Host Institution: Instituto de Química (IQ). Universidade Estadual Paulista (UNESP). Campus de Araraquara. Araraquara , SP, Brazil
• Associated research grant: 15/22828-6 - Pushing the boundaries of optical fibers: from photonics to optogenetics and environmental monitoring, AP.SPEC

Abstract

The control of the electrical and biochemical activity from identified neurons in intact in vivo tissues and understanding their role in brain information processing are for great importance. Current optogenetics techniques offer limited capabilities because they lack selectivity, temporal resolution, and have poor potential for miniaturization. The design of new probes as small as 10¼m, combining electrical and optical detection with single-cell optical resolution at a depth of 6 mm in the intact central nervous system will be the key challenge of this research. The limitation of high electrical resistance (>10 MOhm), which may limit certain types of recordings due to insufficient signal-to-noise ratio can be overcome with the development of functionalized fiber micro-probes combining optical and electrical functionalities. the all is integrated within a single microscopic "all-glass" fiber for minimal disruption to the surrounding tissues, to carry optical and electrical functionalities to the biological site of interest. The pos-doc need to develop an appropriate glass material composition exhibiting an optical transparency of >80% at 500nm wavelength, an AC electrical resistivity of <1 MOhm/cm, a slow kinetics of crystallization suitable for fiber drawing, as well as biocompatible attributes for in-vivo implantation. The micro-optrode development can be achieved through a combination of WO3-AgPO3-AgI glass compositions within the fiber, and careful geometric design to impart fiber multi-functionality, such that each glass composition forms a "conduit" inside the fiber with the desired optical and electrical properties. Compared to other existing technologies, microprobes based on multi-material glass fiber bring economies of scale in manufacturing biomedical probes, and integrate the set of optical and electrical functionalities sought by optogenetics.