A novel microfluidic flow-cytometry for counting numbers of single-cell β-actins

As a house keeping protein with stable expressions, β-actin is used as a loading control in normalization of western blotting. However, the actual numbers of β-actins at the single-cell level remain elusive. Based on a home-developed flow cytometry, single-cell numbers of β-actin from 8 cell types (subtypes) and 2 tumour patient samples were quantified as 9.62 ± 4.29 × 10⁵ (A549, N_cell = 14,242), 6.46 ± 3.34 × 10⁵ (Hep G2, N_cell = 35,932), 1.58 ± 0.90 × 10⁶ (MCF 10A, N_cell = 16,650), 1.08 ± 0.48 × 10⁶ (HeLa, N_cell = 26,151), 7.60 ± 4.34 × 10⁵ (PC3, N_cell = 11,922), 1.10 ± 0.72 × 10⁶ (SACC-83, N_cell = 13,616), 8.58 ± 4.54 × 10⁵ (CAL 27, N_cell = 7271), 9.00 ± 4.69 × 10⁵ (CAL 27-LN2, N_cell = 6222), 8.26 ± 4.48 × 10⁵ (Oral Tumour Patient I, N_cell = 359), and 8.19 ± 5.12 × 10⁵ (Oral Tumour Patient II, N_cell = 175), and were analyzed by statistical approaches including one-way analysis of variance, neural network based pattern recognition and Bayesian estimation, with varied expressions of β-actins among different cell types located. The dataset reported in this study may serve as a reference in future studies of quantitative protein analysis.