Paper-based plasmon-enhanced protein sensing by controlled nucleation of silver nanoparticles on cellulose
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Kemian tekniikan korkeakoulu |
Master's thesis
Ask about the availability of the thesis by sending email to the Aalto University Learning Centre oppimiskeskus@aalto.fi
Authors
Date
2016-05-17
Department
Major/Subject
Renewable Materials Engineering
Mcode
KM3002
Degree programme
Master's Programme in Bioproduct Technology
Language
en
Pages
45+6
Series
Abstract
Proteins such as human serum albumin (HSA) are of special interest. For example, HSA is the most abundant protein in human blood plasma and constitutes about half of serum proteins. HSA is produced only in human liver and is closely related to the overall health. HSA, and in general, protein quantification in liquid matrices is a topic that is highly relevant. Silver nanoparticle (AgNP) formation mediated by cellulosic materials, combined with UV-vis Spectroscopy and surface-enhanced Raman scattering (SERS), are proposed for optical sensing applications with high sensitivity and low cost. SERS has been shown to be a highly sensitive technique. Thus, the aim of this thesis was to develop a paper-based sensor to quantify the concentration of a protein analyte. The work focused on investigating the role of the interactions between silver ions and cellulosic hydroxyl groups, as well as analyte molecules, in AgNP formation and subsequent changes in related optical properties. Based on previous results, ascorbic acid was used as a reducing agent. The kinetics of AgNP formation, in the presence of surfactants was followed by UV-vis spectroscopy that enabled the study of related plasmon effects. Initially, cationic (DDAB), anionic (SDS), and nonionic (Triton X) surfactants were used as model analytes carrying different electrostatic charges. As a proof-of-concept, further investigation was performed with bovine serum albumin (BSA), which was used as a model for HSA. Our kinetic study highlighted opportunities for sensor development based on in-situ AgNP formation: BSA quantification by using UV spectroscopy was possible in the 10–60 mg ml-1 concentration range while that by surface enhanced Raman spectroscopy was extended well below 10 mg ml-1. Thus, the results demonstrated the potential of this proposed, simple method to quantitatively detect a wide range of proteins relevant to bio-diagnostics.Description
Supervisor
Rojas, OrlandoThesis advisor
Arcot, LokanathanKeywords
paper-biosensor, silver nanoparticles, surface plasmon resonance, SERS, UV-vis absorption