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Development ofNano-sensors and Microfluidics towards Raman Spectroscopic Applications

CENTRE FOR NANO SCIENCE AND ENGINEERING INDIAN INSTITUTE OF SCIENCE

T H E S I S C O L L O Q U I U M Title : Development of Nano-sensors and Microfluidics towards Raman Spectroscopic Applications

Speaker: Deepak Ranjan Nayak

Supervisors: Prof. Siva Umapathy, IPC
Prof. Navakanta Bhat, CeNSE/ECE

Date & Time: Friday, 27th July, 10 AM

Venue: CeNSE Seminar Hall

Abstract:

Raman spectroscopy provides identification of analytes with unique fingerprint spectra but lacks sensitivity due to weak scattering process. Surface enhanced Raman spectroscopy (SERS), a specialized technique derived from the effect of normal Raman scattering of analyte in the vicinity of metal surface, brings specificity and sensitivity together. On the other hand, microfluidics involves fluid manipulation in microscale giving rise to interesting effects which can be employed to perform certain operations on analyte before SERS. Integration of SERS substrate with microfluidics have been attempted to increase the potential application and versatility of both the tools.

The first part of the work focuses on fabrication of large area SERS substrates. Metal nanoparticles were fabricated on base substrate of silicon and dielectrics through DC magnetron sputtering and annealing. The efficiency of the substrates primarily depends on the interaction between plasmonic nanoparticle and base substrate. This interaction has been studied through numerical simulation and analytical modeling to understand the mode of interaction resulting in an efficient substrate. Large area nanostructures such as anodized alumina template (AAOT) and germanium nanowire (through PECVD) coated with silver, have been studied for SERS activity. Highly tunable and efficient substrates have been fabricated by creating silver structure on GeNWs through galvanic displacement.

The second part of the work discusses development of centrifugal microfluidic system for blood plasma separation and cell content (RBC/WBC) separation. A valve design has been proposed to efficiently interconnect multiple microfluidic operations on a single disc. Fabrication methodology has been developed to increase the chamber height which in turn increases the throughput as well as aids in incorporation of SERS substrate in the device.

Date: 
Thursday, 27 July 2017 - 4:30am