Urimem, a membrane that can store urinary proteins simply and economically, makes the large-scale storage of clinical samples possible

Biological samples from patients are invaluable for both medical research and medical practice. Ideally, the samples should be preserved for the same period of time as the duration of their corresponding medical records. Urine is a body fluid that can be non-invasively acquired, and it contains important biological information about the patient. Unlike blood which has mechanisms to keep the internal environment homeostatic, urine is more likely to reflect changes of the body. In other words, urine is likely to be a better biomarker source than blood. Here, we propose a method to adsorb urinary proteins onto a polyvinylidene fluoride (PVDF) membrane called Urimem. The method is very simple and inexpensive and requires minimal sample handling. It does not use organic solvents, and it is environmentally friendly. The proteins on the membrane are dried and stored in vacuum bag, which keeps the protein pattern faithfully preserved. The membrane may even permit storage at room temperature for weeks. The quantity of eluted proteins from the membrane is sufficient for biomarker validation experiments. Using this simple and inexpensive urinary protein preservation method, it is possible to begin preserving urine samples from all consenting patients. Thus, medical research especially biomarker research can be conducted more economically, ultimately benefiting the patients who provided the samples. This sample storage approach can facilitate the biomarker research and potentially change the landscape of medical research and medical practice.