Chemical-Modified Nucleotide-Based Elemental Tags for High-Sensitive Immunoassay

Abstract

Multiplex biomolecular analysis with inductively coupled plasma mass spectrometry (ICP-MS) becomes increasingly important in clinical diagnosis and single cell analysis. However, the sensitivity of ICP-MS-based immunoassay is only comparable or lower than those of fluorescence methods at the present stage. Therefore, designing elemental tags with a large number of metal atoms is necessary to achieve high-sensitive detection. In this work, we proposed a new strategy to build up elemental tag loading with hundreds of rare earth ions by coupling alkyne-DNA chains with rare earth element (REE)-DOTA complexes a click chemistry reaction. There are about 2 orders of magnitude improvement in sensitivity compared with single metal-ion tags. DNA chains with multialkynyl groups were facilely prepared by PCR synthesis. Moreover, the DNA-based elemental tags own excellent water-solubility and biocompatibility. The tags would be potentially applied to mass cytometry and clinical diagnosis.

Element coding based accurate evaluation of CRISPR/Cas9 initial cleavage

“…The alkyne-ntDNA labeled with N 3 -DOTA-[Ln] element tag by click chemistry reaction followed previous reports. 34,35 First, 100 μM alkyne-ntDNA solution dissolved by PBS buffer (10 mM, pH=7.4) was pre-heated to 95 ℃ for 2 min, then rapidly cooled to 25 ℃. After that, 20 -fold access 3c).…”

Immunoassays based on inductively coupled plasma mass spectrometry detection: So far so good, so what?

“…However, since the water solubility of this kind of element tags decreases when the polymer chain length increases, the number of REE ions per tag is limited for practical purposes [50]. Recently, Hu et al [51] have developed a novel DNA element tags by coupling REE-DOTA complexes with DNA chains containing alkynylmodified tyrosine residues through a click chemistry reaction (i.e. Cu (I)-catalyzed Huisgen cycloaddition).…”

“…Carboxyl groups are not usually employed for element tag conjugation but for immobilization purposes after an alkaline activation step (e. g. with carbonate-bicarbonate buffer) [16,31,32,48,51,61,65,66,69,74]. On this regard, it is worth to mention that most of the conjugation above-described are not exclusively employed for direct elementtagging but for antibody immobilization on solid supports [33,35,36,49,58,62,63], as well as for the introduction of biotin to make use of the well-known biotin-streptavidin system [16,32,34,48,51,54,61,66,74].…”

Mass Spectrometry Methods for In Situ Analysis of Clinical Biomolecules

“…ICP‐MS is usually conducted for liquid samples. Zhang's group developed a DNA elemental tag binding with hundreds of rare earth ions during immunoassays . Cancer biomarkers of CEA, α‐fetoprotein (AFP), and ferritin (FER) were detected with two orders of magnitude improvement in sensitivity compared with single metal‐ion tags.…”