Peptide detection in single cells using a dot immunoblot assay.

A highly sensitive dot immunoblot assay (DIA) for the detection and quantitative measurement of small peptides in single cells is presented. This DIA protocol is simple, rapid, and produces no radioactive waste. Its femtomole sensitivity is 100 fold greater than previously described DIAs. This DIA method is sufficiently sensitive to allow reliable peptide measurements to be obtained from a single cell in a manner than is faster and easier than other peptide detection procedures. This method can also be used for several other purposes, including assessing antibody specificity and peptide quantification.