Nowadays, a great research effort is put into the development of techniques enabling early diagnosis of genetic disorders, including different types of cancer [1]. Among those techniques, polymerase chain reaction or different... [ view full abstract ]
Nowadays, a great research effort is put into the development of techniques enabling early diagnosis of genetic disorders, including different types of cancer [1]. Among those techniques, polymerase chain reaction or different types of blotting are mostly used for DNA mutation detection as a part of cancer treatment [2]. However, those methods lack of sensitivity and can detect DNA mutations only in advanced stage of the disease. Therefore, new detection tools are needed as alternatives to the techniques which are used routinely, in order to improve the early detection in diagnostics. One of the promising technique developing very fast in the field of cancer diagnosis is surface enhanced Raman spectroscopy (SERS). This method, discovered in 1974 by Fleischmann, is based on a huge enhancement of the Raman signal (up to 14 orders of magnitude) when the molecule is adsorbed on the rough metal surface [3]. The most commonly used metal substrate is colloidal gold and silver, because of relatively easy way of preparation and repeatable results [4]. SERS spectroscopy, because of its ultrasensitive detection limits, is a perfect method for detection of biomolecules at very low concentrations.
The idea of SERS-based sensors for DNA detection is quite simple: capture DNA, complimentary to target DNA, is immobilized on metal surface, then target DNA is added and this hybrid is labeled with another single stranded DNA modified with an organic dye [5].
Immobilization of capture DNA on the metal surface is a crucial moment influencing effectiveness of the sensor. Here we present the optimization of the formation of ssDNA monolayer on SERS substrate taking into consideration: type of metal surface, pH, presence of small molecules between ssDNA (6-mercapto-1-hexanol) and how these conditions influence the hybridization process.
Acknowledgement: Work implemented as a part of Operational Project Knowledge Education Development 2014-2020 cofinanced by European Social Fund.
References:
[1] J.Wang, Biosensors and Bioelectronics 21 (2006) 1887; [2] X.Zhu et al., Biosens.Bioelectron. 74 (2015) 113; [3] M.Fleischmann et al., Chem.Phys.Lett. 26 (1974) 163; [4] G. Frens, Nature Phys Sci. (1973) 241, 20; [5] F. Peng et al., Acc.Chem.Res., 47 (2014) 2, 612
