Polymer‐Based Elemental Tags for Sensitive Bioassays

Abstract

To identify a rare (e.g., diseased or foreign) cell in a complex mixture, or to understand the proteomic complexity[1,2] of cells, one needs to be able to measure simultaneously and quantitatively a large number of proteins or other biomarkers that may be present in a complex sample. This is a difficult task and is beyond the reach of current capabilities. To address a problem of this complexity, we have begun to develop a high-sensitivity assay[3-6] based upon elemental tags that will enable the simultaneous measurement of many proteins in a single sample. The advantage of this approach lies in the large number of available elements and isotopes (potentially greater than 79) found in low abundance in biological systems, which will allow multiple tags to be used simultaneously. Inductively coupled plasma mass spectrometry (ICP-MS) is an ideal technique for detecting and quantifying these tags, as ICP-MS provides excellent resolution between the tag masses and an exceptional dynamic range (nine orders of magnitude). [7] This method allows one to overcome some of the limitations of currently available fluorescent tagging approaches.[8] These limitations arise from the spectral overlap of different dyes and the difficulty in measuring simultaneously targets that differ in abundance

Mass Cytometry: Protocol for Daily Tuning and Running Cell Samples on a CyTOF Mass Cytometer

“…[1][2][3] Due to the purity of the metals and the mass resolution of ICP-MS, there is effectively no "spectral overlap." Since most of the elements used are not biologically relevant, there is also little background to cause "autofluoresence."…”

“…[2][3][4][5] Because of the metal purity and mass resolution of the mass cytometer, there is no "spectral overlap" from neighboring isotopes, and therefore no need for compensation matrices. Additionally, due to the use of lanthanide metals, there is no biological background and therefore no equivalent of autofluorescence.…”

ICP‐MS‐Based strategies for protein quantification

“…Lou et al (2007) recently developed a new class of polymer-based elemental tags for ICP-MS detection. This water-soluble polymer contains multiple metalchelating ligands and offers the important advantages that each tag carries many copies of a given element, which greatly increases the assay sensitivity.…”

“…This water-soluble polymer contains multiple metalchelating ligands and offers the important advantages that each tag carries many copies of a given element, which greatly increases the assay sensitivity. It is possible to achieve detection limits at the order of parts per billion, which will allow the detection of cell surface markers with copy numbers as low as 100 (Lou et al, 2007).…”

Matrix-Assisted Ionization-Ion Mobility Spectrometry-Mass Spectrometry: Selective Analysis of a Europium–PEG Complex in a Crude Mixture

“…For example, LCCC separates polymers based on structural differences, including functionality type distribution, composition distribution of copolymers, or differences in microstructure or topology independent of the molecular mass [32,42,43]. Approaches hyphenating LC to inductively coupled plasma (ICP)-MS have been used to quantify metal complexes within other crude, biological samples [44][45][46][47], including synthetic polymers [48].…”