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Additional Information

Competing Interests

The authors declare that they have no competing interests.

Author Contributions

Lulu Jia performed the experiments, analyzed the data, wrote the paper.

Xuejiao Liu performed the experiments.

Liu Liu performed the experiments, wrote the paper.

Mingxi Li contributed reagents/materials/analysis tools.

Youhe Gao conceived and designed the experiments, wrote the paper.


The following information was supplied relating to ethical approvals (i.e., approving body and any reference numbers):

This study aims to establish a method that uses PVDF membranes to preserve urinary proteins. In this methodology study, only normal human urine was collected naturally from volunteer students in our lab. As human waste, no invasive measures were taken. All participants provided verbal informed consent to allow us to use their urine samples for this study. No written consent was provided because none of participants thought it was necessary. The verbal consent was documented in the laboratory notebook of the authors. The verbal consent procedure and research protocol in this study were approved by the Medical Ethics Committee of Peking Union Medical College (Project No:018-2013).


This work was supported by the National Basic Research Program of China (2012CB517606, 2013CB530805, 2011CB964901), the National High Technology Research and Development Program of China (2011AA020116), Program for Changjiang Scholars and Innovative Research Team in University-PCSIRT (IRT0909), and 111 Project (B08007). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

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