Label-free capacitive DNA sensor using immobilized pyrrolidinyl PNA probe: Effect of the length and terminating head group of the blocking thiols

Advances in Plasmonic Technologies for Point of Care Applications

“…135 To evaluate these parameters, a number of alkanethiol SAMs (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 headgroup, and 1-dodecanethiol (1-DDT)) was used for the detection of the target DNA sequences using pyrrolidinyl peptide nucleotide acid (acpcPNA) probes that were immobilized via a spacer molecule. 135 The blocking thiol compound with same length (9-MNL) as the total spacer molecule provided the highest sensitivity [20.4 ± 0.7 nF cm –2 (log M) −1 ] compared to the other thiol blocking agents with shorter and longer length. 135 This specific length possibly arranged more favorable hybridization, resulting in the highest hybridization efficiency, whereas the blocking agent with longer length overlapped with the probe.…”

“…135 The terminal groups (i.e., −OH and −CH 3 ) of thiol blocking agents were also evaluated on the same platform, and the hydroxyl-terminated agent provided a slightly better sensitivity by increasing hydrophilicity for DNA immobilization and hybridization. 135 Proteins (e.g., bovine serum albumin, casein, glycine, and gelatin) have been also used to protect the biosensing surface from nonspecific interactions. Instantized dry milk, casein, gelatins from pig and fish skin, and serum albumin were evaluated to understand the blocking capabilities, and casein and instantized milk were observed to inhibit nonspecific binding.…”

Capacitive Biosensors and Molecularly Imprinted Electrodes

“…Pyrrolidinyl peptide nucleic acid probes were immobilized onto the self-assembled monolayer (SAM) modified gold electrode surface to develop a DNA capacitive biosensor [16]. Four different alkanethiols with various chain lengths were used as a SAM to determine the influence of the length and the terminating head group of blocking thiols on the sensitivity and specificity.…”

Quaternized chitosan particles as ion exchange supports for label-free DNA detection using PNA probe and MALDI-TOF mass spectrometry

“…This PNA system possessed higher binding affinity and sequence specificity toward DNA than that of Nielsen's PNA, and with a much stronger preference for the antiparallel binding mode (Ananthanawat, Vilaivan, Hoven, & Su, 2010;Suparpprom, Srisuwannaket, Sangvanich, & Vilaivan, 2005;Vilaivan & Srisuwannaket, 2006). The powerful discrimination for single mismatched DNA makes acpcPNA a potential candidate for the development of highly effective DNA biosensors, which has been continuously proven for both labeling (Boonlua, Vilaivan, Wagenknecht, & Vilaivan, 2011;Maneelun & Vilaivan, 2013;Mansawat, Boonlua, Siriwong, & Vilaivan, 2012;Rashatasakhon, Vongnam, Siripornnoppakhun, Vilaivan, & Sukwattanasinitt, 2012;Reenabthue, Boonlua, Vilaivan, Vilaivan, & Suparpprom, 2011) and non-labeling techniques (Ananthanawat, Hoven, Vilaivan, & Su, 2011;Ananthanawat, Vilaivan, Mekboonsonglarp, & Hoven, 2009;Jampasa et al, 2014;Sankoh et al, 2013;Theppaleak, Rutnakornpituk, Wichai, Vilaivan, & Rutnakornpituk, 2013a, 2013bThipmanee et al, 2012).…”