Degree Type

Creative Component

Semester of Graduation

Spring 2021


Electrical and Computer Engineering

First Major Professor

Jaeyoun Kim


Master of Science (MS)


Electrical Engineering


The world of nanosensors has been incessantly expanding and it has found its use in building biological sensors which aid in determining the concentration of biomolecules in both in-vivo and ex-vivo experiments. Because of the expense and time constraints associated with modern laboratory analysis, there is a growing need for real-time, low-cost technology that can be

used industrially, environmentally, and clinically. Miniaturization, integrated systems, and multianalyte determination have become key aspects of sensor development. The integration of such nano biosensors with fiber optics has expedited this expansion of nano biosensors and this modern amalgamation has till now been used in numerous biological/biochemical applications.

With the coming in of fiber optic probes in biosensors, the concept of surface plasmon waves also came into limelight. Plasmonic fiber-optic biosensors combine the flexibility and compactness of optical fibers and high sensitivity of nanomaterials to their surrounding medium, to detect biological species such as biomolecules, proteins, DNA as well as cancer cells, tumor cells. Due to their small size, accuracy, low cost, and possibility of remote and distributed sensing, plasmonic fiber-optic biosensors are promising alternatives to traditional methods

for biomolecule detection, and can result in significant advances in clinical diagnostics, drug discovery, food process control, disease, and environmental monitoring. Plasmonic fiber optic probe was also shown to be used as a Surface enhanced Raman spectroscopy (SERS) substrate. SERS is a technique that is used to amplify inherent Raman scattering signals using roughened (nanostructured) metallic (e.g., Au and Ag) surfaces and/or metal nanoparticles (NPs). In this report, a novel fiber-optic SERS probe, known as SERS-on-a-tip or SOT, along with accurate intracellular and extracellular pH detections by the SERS method, was introduced and briefly explained.

Any data about fiber optic integrated biosensor is incomplete without a thorough analysis of fabrication techniques. This report fulfills this criteria by explaining different types of fabrication methodologies including the traditional ones like Focused ion beam (FIB), electron beam lithography (EBL), Interference and nanoimprint lithography, as well as the modern techniques like Breath Figure, Two photon polymerization (2PP). This report also talks in brief about instrumentation required and method to actually detect biomolecules mentioned in the first paragraph, namely E. Coli and cancer tumor cells. It calculates the Limit of detection(LOD), as well as Refractive Index sensitivity of the nanoprobe that is used for detection, quite accurately.

Copyright Owner

Rijal, Mehul

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