New Structure Mass Tag based on Zr‐NMOF for Multiparameter and Sensitive Single‐Cell Interrogating in Mass Cytometry

Abstract

Mass cytometry, also called cytometry by time‐of‐flight (CyTOF), is an emerging powerful proteomic analysis technique that utilizes metal chelated polymer (MCP) as mass tags for interrogating high‐dimensional biomarkers simultaneously on millions of individual cells. However, under the typical polymer‐based mass tag system, the sensitivity and multiplexing detection ability has been highly restricted. Herein, a new structure mass tag based on a nanometal organic framework (NMOF) is reported for multiparameter and sensitive single‐cell biomarker interrogating in CyTOF. A uniform‐sized Zr‐NMOF (33 nm) carrying 105 metal ions is synthesized under modulator/reaction time coregulation, which is monodispersed and colloidally stable in water for over one‐year storage. On functionalization with an antibody, the Zr mass tag exhibits specific molecular recognition properties and minimal cross‐reaction toward nontargeted cells. In addition, the Zr‐mass tag is compatible with MCP mass tags in a multiparameter assay for mouse spleen cells staining, which exploits four additional channels, m/z = 90, 91, 92, 94, for single‐cell immunoassays in CyTOF. Compared to the MCP mass tag, the Zr‐mass tag provides an additional fivefold signal amplification. This work provides the fundamental technical capability for exploiting NMOF‐based mass tags for CyTOF application, which opens up possibility of high‐dimensional single‐cell immune profiling, low abundant antigen detection, and development of new barcoding systems.

Metal‐Chelatable Porphyrinic Frameworks for Single‐Cell Multiplexing with Mass Cytometry

“…in the tested Jurkat cell group, which was confirmed by staining the Jurkat cells with the commercial (Maxpar ® ) 171 Yb@MCP_PD-1 marker (Figure S7). Staining Ramos cells with Sn@MPF_PD-1 resulted in low signals with MSI of 10.1 � 4.7, confirming the low NSB similar to the reported NP-based CyTOF markers, [16,21] which is possibly due to the PEG segments in the APEB coating on the MPF NPs. [27,28] We further investigated the concentration effect on the specificity of our Sn@MPF_PD-1 tags for staining single type of cells.…”

“…Current design strategies for CyTOF markers include metal‐chelating polymers (MCP), [3–13] nanoscale aggregates of noble metals, [14, 15] inorganic nanoparticles (NPs), [16–20] and coordinated metal‐containing clusters [21] . However, these approaches still face difficulties in resolving the limited multiplexing capability of CyTOF.…”

“…[3,22] While nanoscale aggregates of noble metals and inorganic NPs may achieve higher CyTOF sensitivity than MCPs, [14][15][16] the synthesis of these structures generally requires complicated metal-specific optimization, posing challenges in widely expanding the detection channels of CyTOF. Previous attempt to apply coordinated metal-containing clusters, such as the zirconium nanoscale metal-organic framework (Zr-NMOF), [21] to CyTOF was based on the intrinsically high density of metals in the MOF nodes, which is similar to the metal and inorganic NPs. Using framework materials as chelating scaffolds have not yet been explored.…”

Polymeric dipicolylamine based mass tags for mass cytometry

“…We note that a more successful Zr mass tag based upon metalorganic framework nanoparticles has recently been reported. 31 In this contribution, we describe the synthesis of a new type of metal-chelating polymer with pendant dipicolylamine (DPA) chelators that can complex with the rhenium tricarbonyl core (fac-[Re(CO) 3 ] + ) or with the platinum(II) ion. For the rhenium mass tag, the initial polymer synthesized, with a polyacrylamide backbone, a lysine-based spacer, DPA pendant groups and a maleimide functional end group, was soluble in water, but its fac-[Re(CO) 3 ] + complex caused the polymer to precipitate.…”

“…We note that a more successful Zr mass tag based upon metal–organic framework nanoparticles has recently been reported. 31 …”