PDMS devices integrated with anodized aluminum oxide membranes for DNA detection based on gold nanoparticles amplification

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PDMS devices integrated with anodized aluminum oxide membranes for DNA detection based on gold nanoparticles amplification

 

Author: Lai, Mei Fung
Title: PDMS devices integrated with anodized aluminum oxide membranes for DNA detection based on gold nanoparticles amplification
Degree: M.Sc.
Year: 2013
Subject: DNA -- Analysis.
Nanoparticles.
Hong Kong Polytechnic University -- Dissertations
Department: Interdisciplinary Division of Biomedical Engineering
Pages: xvii, 73 leaves : ill. (some col.) ; 30 cm.
Language: English
InnoPac Record: http://library.polyu.edu.hk/record=b2648912
URI: http://theses.lib.polyu.edu.hk/handle/200/7187
Abstract: In the past few years, many different types of virus and bacteria appeared in the world. These virus and bacteria caused a serious of problems. Since their presences were usually undetectable in low concentration, many people were infected and even died eventually. In order to reduce the severities of the consequences caused by these viruses, sensitive detection is very important for patient to receive treatment earlier. Using the fact that the DNA sequences of different viruses and bacteria are different, DNA detection can be used to recognize the presence of complimentary DNA inside the human body. In this study, a simple, label-free, sensitive PDMS device integrated with AAO membranes were fabricated for DNA detection. For the aim of detecting specific DNA in low concentration, gold nanoparticles (AuNPs) were conjugated to the complimentary DNA to amplify the sensing signal. The impedance change due to DNA hybridization was measured by an impedance analyzer VersaSTAT3. The effect of concentration of AuNP-DNA on the impedance was investigated in the first part. With the increasing concentration of AuNP-DNA, impedance keeps increasing initially and reaches the highest value under the optimal concentration of AuNP-DNA. After the optimal concentration, impedance decreases. For the AAO membranes with pore size 100nm, the optimal concentration of AuNP-DNA for 13nm AuNPs is 2.6nM. For the AAO membranes with pore size 200nm, the optimal concentration of AuNP-DNA for 15nm, 30nm and 50nm AuNPs are 0.08nM, 0.04nM and 0.02nM respectively. In the second part, the relationship between the size of AuNPs and the concentration of AuNP-DNA was investigated. The smaller the sizes of AuNPs, the higher the concentration of AuNP-DNA is. The results found in this study help to understand the blocking effect of AuNPs and, choose the suitable size of AuNPs and concentration of AuNP-DNA to increase the sensitivity for DNA detection in low concentration.

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