A K⁺-mediated G-quadruplex formation enhancement fluorescence polarization system based on quantum dots for detection of Hg²⁺ and biothiols

Abstract

A fluorescence polarization homogenous system based on CdTe/CdS QDs that employed a K(+)-mediated G-quadruplex as an enhancer was identified for sensitive and selective detection of Hg(2+) and biothiols in complex samples.

Sensitive Hg2+ Sensing via Quenching the Fluorescence of the Complex between Polythymine and 5,10,15,20-tetrakis(N-methyl-4-pyridyl) Porphyrin (TMPyP)

“…The inset of Figure 5 B depicted the linear portion of the curve with Hg 2+ concentrations ranging from 5 nM to 100 nM and the linear regression equation was presented as (F 0 − F)/F 0 = 3.22 [Hg 2+ ] (μM) + 0.05 ( R 2 = 0.9605). The detection limit was estimated to be 1.3 nM, being much lower than those by the 8-amino BODIPY-based fluorescence assay (49 nM) [ 31 ], Raman spectroscopic method (10 nM) [ 32 ], colorimetric assay employing plasmonic gold nanoparticles (50 nM [ 33 ] and 17.3 nM [ 34 ]), colorimetric assay based on Cu 2-x Se nanoparticles (2.7nM) [ 35 ] and the fluorescence polarization assay based on CdTe/CdS quantum dots (8.6 nM) [ 36 ]. Such a concentration level was also comparable with those by fluorescent assay based on phosphorothioate RNA modifications (1.7 nM) [ 37 ].…”

A mini-review on functional nucleic acids-based heavy metal ion detection

“…Besides the π-surfaces, the central negatively charged channel inside the G-quartet stack that attributed to the lone pairs on the O 6 atoms (with strong negative electrostatic potential) surrounding the central core also tempt the cations coordination (Ou et al, 2008). Based on the structure and property changes of G-quadruplex arouse from the cations coordination, researchers designed various strategies for the detection of Pb 2+ Zhan et al, 2013), Hg 2+ (Ren et al, 2016;Willner et al, 2008), Cu 2+ Zhang et al, 2013a), Ba 2+ (Yang et al, 2013), Ag + Yang et al, 2016;Zhou et al, 2009), K + (Chen et al, 2013b;Wang et al, 2014a;Zhang et al, 2014b), and so on. …”

Recent progress in nanomaterial-enhanced fluorescence polarization/anisotropy sensors

“…Recently, a number of nanomaterial, such as carbon nanoparticles (CNPs), gold nanoparticals (AuNPs), metal-organic frameworks (MOFs), SiO2 nanoparticals (SiO2 NPs), graphene oxide (GO), quantum dots (QDs), carbon nanotubes (CNTs), 2D transition metal dichalcogenide nanosheets (TMD NSs), MnO2 nanosheets were introduced into FP/FA sensor system, has brought revolutionary effect for greatly improving detection sensitivity and application range of FP/FA, due to its unique structure and extraordinary properties such as simple/controllable synthesis and modification, different sizes, large volumes and masses, chemical compositions and morphologies, excellent optical and chemical properties [26][27][28][29][30][31][40][41][42][43][44]. Table 1 lists various targets of interest, FP/FA enhancer and signal amplification methods, analytical performance, and so on [40][41][42][43][45][46][47][48][49][50][51][52][53][54][55][56][57][58][59][60].…”

“…The determination of small molecule and metal ion is associated with many diseases and biological process [89,90]. A great deal of small molecules and metal ions, e.g., silver ions [43], adenosine [48], toxin [48,59,91], mercury (II) ions or biothiols [56,58], copper (II) ions [57], ATP [60], organophosphorus pesticide [92], and so on [55], were highly sensitively measured by nanomaterial-based FP/FA. For example, Tian's group [56] constructed a simple, highly selective and sensitive FP assay based on CdTe/CdS QDs using a K + -mediate G-quadruplex as a FP enhancer for the determination of biothiols and Hg 2+ in complex biological matrix.…”