Computational Systems Biology Methods and Protocols.7z

Chapter 17

Single-Cell Protein Assays: A Review

Beiyuan Fan, Junbo Wang, Ying Xu, and Jian Chen

Abstract

Quantification of single-cell proteomics provides key insights in the field of cellular heterogeneity. This
chapter discusses the emerging techniques that are being used to measure the protein copy numbers at the
single-cell level, which includes flow cytometry, mass cytometry, droplet cytometry, microengraving, and
single-cell barcoding microchip. The advantages and limitations of each technique are compared, and
future research opportunities are highlighted.

KeywordsSingle-cell protein assays, Flow cytometry, Mass cytometry, Droplet cytometry,

Microengraving, Single-cell barcoding microchip

1 Introduction

Proteins (i.e., macromolecules composed of chains of amino acid

residues) perform dominant functions within organisms, which

function as key regulators in metabolic reactions, DNA replications,

signal transductions, and molecule transportations [1]. Thus, the

status of proteins has been regarded as the most important indica-

tors of biological activities, which are closely related to cellular

differentiation, neuron transmission, and disease progressions, to

name a few [2].

A large number of characterization approaches (e.g., immuno-

assay and electrophoresis) have been proposed to estimate protein

expressions [3], which significantly promote the developments in

biological and medical sciences [4]. However, these conventional

approaches can only quantify protein copy numbers in population

and cannot be used to address the issue of cellular heterogeneity.

Within the last decades, we have witnessed huge developments

in tools enabling single-cell protein analysis, providing key insights

in the field of cellular heterogeneity (e.g., immune response varia-

tions and tumor heterogeneity) [5–8]. Currently, approaches in the

field of single-cell protein analysis can be classified into five major

types, which are (1) flow cytometry, (2) mass cytometry, (3) droplet

Tao Huang (ed.),Computational Systems Biology: Methods and Protocols, Methods in Molecular Biology, vol. 1754,
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