New urinalysis shows promise for patients with kidney stones

With an improved urinalysis system for people suffering from kidney stones, inspired by nature and proposed by researchers at Pennsylvania State University and Stanford University, patients can now spend less than 30 minutes instead of the current week or longer. You can receive the results.

Kidney stones are the result of the accumulation of certain salts and minerals that form crystals, which then stick together and expand, forming a hard mass in the kidneys. Stones can travel to the urinary tract and cause blood in the urine, considerable pain and obstruction of the urinary system.

Urine metabolism tests in patients with kidney stones identify the metabolites such as minerals and solutes that form stones, which is the key to preventing future stones. The test is currently done by requiring patients to collect urine in large containers for 24 hours. The container is then sent to the lab for analysis and the results are usually returned in 7-10 days.

“Despite the guideline recommendations, 24-hour urinalysis is underutilized in the clinical setting due to lengthy processes, tedious collection procedures, and delays in obtaining results. ) Was published in Scientific progress..

According to Wong, expensive special equipment is needed to detect solutes and minerals in urine to obtain test results. Therefore, urine samples should be shipped to a commercial diagnostic lab for testing. To solve this, the research team has developed a biomimetic detection system called the slippery liquid-injected porous surface (SLIPS) -LAB.

SLIPS are dynamic, very low-friction, smooth surfaces created by immobilizing a lubricant on a micro / nanostructured substrate. It was inspired by the Nepenthes pitcher plant. It is a carnivorous plant filled with digestive juices, which has unique leaves shaped like a pitcher. The plant evolves the edges of microtextures infused with a very slippery liquid, causing insects to fall into a “pitcher”.

“There are many aspects that we can learn from nature and the environment, and our research is an example of how biomedical engineers can use it,” Wong said.

SLIPS-LAB prevents reagent and urine droplets from easily migrating and sticking on the smooth surface of the liquid addition channel of the test device. The droplets are driven by the Laplace pressure differential, a small pressure due to surface tension induced by the geometry of the device. This allows the reactants to combine with urine at the timed rate required for the reaction.

“We showed that SLIPS-LAB automatically moves reagents and samples and runs the reaction,” says Wong. “This means the technician doesn’t need a technician to run the test machine, so it’s possible to perform the test in a non-traditional environment, such as a doctor’s office or a patient’s home. “

You can then use your scanner or mobile phone to read the test results and use computer algorithms to analyze the scanned images. According to Wong, all these steps take about 30 minutes at the doctor’s office. According to Wong, SLIPS-LAB also has the advantage of being more cost-effective than the regular 24-hour test.

“The low cost, speed and simplicity of SLIPS-LAB will reduce the barriers for clinicians and patients to undergo stone risk metabolite analysis,” Wong said. “This will improve the management of patients with urinary tract stone disease and open new possibilities for calculus patients to test urine samples in a mobile health environment.”

Hui Li, a graduate student in biomedical engineering who is the lead author of the study, said that another promising result of their study was that patients could be treated as a spot test, so patients would A collection that means you can monitor a specific level of urine in no time.

“SLIPS-LAB may open up new opportunities for on-demand monitoring of urine specimens, potentially changing the metabolic assessment and clinical management of urolithiasis,” Li said.