CHA University team detects 5,600 proteins in a sample of about 20 cells with the nbDIA method

A research team led by Professor Park Junho at the CHA University School of Medicine has developed a method that identifies thousands of proteins in a sample equal to a few dozen cells, thefirstmedia.net reports. The work was done jointly with the pathology team of Seoul National University Hospital and MeteoBiotech, and was published in Analytical Chemistry, a journal of the American Chemical Society. thefirstmedia.netthefirstmedia.netthefirstmedia.netOpen source ↗ The authors optimized the measurement conditions of existing analytical instruments, so no additional dedicated equipment was required.

How the nbDIA method works

Proteomics measures the proteins in cells or tissue to characterize the causes and biological features of disease. The fewer cells in a sample, the fewer proteins can be detected. The team combined BoxCar measurement, which efficiently detects weak peptide signals, with narrow-window data-independent acquisition (DIA), which raises analytical precision. The result is a new method called nbDIA. In a sample of about 20 cells it detected more than 5,600 proteins, and repeated runs showed no large variation in measured values.

Test on breast cancer tissue

To assess use with clinical samples, the team applied the method to tissue from patients with HER2-positive breast cancer. They isolated 20 microregions of about 30 to 60 cells each and detected more than 6,100 proteins. Within the same tumor, protein composition differed between regions with high and low HER2 expression. Compared with gene expression data from the same tissue, protein analysis showed activation of a HER2-related signaling pathway that gene analysis had not revealed.

Park said the technique could be used to study heterogeneity inside tumors, analyze small cell populations and search for clinical biomarkers. Application to diagnosis or treatment would require further validation on samples from a variety of patients.