Collection and preservation of urinary proteins, using a fluff pulp diaper

Abstract

Change is the most fundamental property of a biomarker. In contrast to the blood, which is under homeostatic controls, urine reflects changes in the body earlier and is more sensitive, thus making it a better biomarker source. Moreover, drawing blood from infants and toddlers is difficult and not tolerated well. For patients limited by language, communicating their chief complaint is difficult. Thus, monitoring biomarkers in urine can provide valuable clues for the diagnosis of diseases, especially pediatric diseases. Collecting urine from young children and some adult patients is more challenging than collecting it from healthy adults. Here, we propose a method that uses a fluff pulp diaper to collect urine. Urinary proteins are then eluted and adsorbed onto a piece of nitrocellulose membrane, which can be dried and stored in a vacuum bag. SDS-PAGE and LC-MS/MS analysis indicated that this method is reproducible, and similar proteins were identified as those obtained by an acetone precipitation method. With this simple and economical method, it is possible to collect and preserve urine samples from infants, toddlers, and patients with special needs, even for large-scale biomarker studies.

Urinary malate dehydrogenase 2 is a new biomarker for early detection of non‐small‐cell lung cancer

“…For longer storage, the urinary supernatants were diluted with phosphate buffer, pH 7.5 and then the urinary protein was fixed on 22μm nitrocellulose membranes (Millipore) using vacuum filtration and stored at −80°C. 19 For human urinary protein extraction, the nitrocellulose membranes on which sample urinary protein was fixed were cut into pieces and dissolved in acetone containing 0.5% ammonium bicarbonate with vigorously shaking. Samples were incubated at 55°C for 60 min with vigorous shaking every 20 min.…”