Home
Resources
Publications
Label-free Capacitive DNA Sensor Using Immobilized Pyrrolidinyl PNA Probe: Effect of the Length and Terminating Head Group of the Blocking Thiols

Label-free Capacitive DNA Sensor Using Immobilized Pyrrolidinyl PNA Probe: Effect of the Length and Terminating Head Group of the Blocking Thiols

Orawan Thipmanee, Saluma Samanman, Supannee Sankoh, Apon Numnuam, Warakorn Limbut, Proespichaya Kanatharana, Tirayut Vilaivan, Panote Thavarungkul

Biosens Bioelectron. Oct-Dec 2012;38(1):430-5.

PMID: 22770826

Abstract:

This paper reports, for the first time, the influence of the length and the terminating head group of blocking thiols on the sensitivity and specificity of a label-free capacitive DNA detection system using immobilized pyrrolidinyl peptide nucleic acid (acpcPNA) probes. A C-terminal lysine-modified acpcPNA was immobilized through four different alkanethiol self-assembled monolayers (SAMs), i.e., 3-mercaptopropionic acid (MPA), thioctic acid (TA), thiourea (TU) and mercaptosuccinic acid (MSA). The hybridization between the acpcPNA probes and the target DNA was directly measured using the capacitive system. Five blocking thiols of various lengths (C=3, 6, 8, 9 and 11), with the -OH terminating head group, i.e., 3-mercapto-1-propanol (3-MPL), 6-mercapto-1-hexanol (6-MHL), 8-mercapto-1-octanol (8-MOL), 9-mercapto-1-nonanol (9-MNL), 11-mercapto-1-undecanol (11-MUL) and another blocking thiol (C=11) with a -CH(3) terminating head group, and 1-dodecanethiol (1-DDT) were investigated. The blocking thiol with the same length as the total spacer of the immobilized acpcPNA gave the highest sensitivity and specificity with the -OH terminating head group providing a slightly better signal than the -CH(3) group. Under the optimized conditions, the immobilized acpcPNA probes provided a wide linear range for DNA detection (1.0 × 10(-11)-1.0 × 10(-8)M) with a very low detection limit in the picomolar range. The modified acpcPNA electrode could be reused through at least 58 cycles. The high sensitivity and very low detection limits are potentially useful for the analysis of ultra-trace levels of DNA in samples. Preliminary studies were also performed to see the effect of probe concentration and target length.

Chemicals Related in the Paper:

Catalog Number	Product Name	Structure	CAS Number	Price
AP19721223	3-Mercapto-1-propanol		19721-22-3	Price

As a specialist in analytical chemical Products, Alfa Chemistry offers consumers a wealth of raw materials and a full range of technologies and services.

QUICK LINKS

HEADQUARTERS

Tel:

Fax:

Email: