Team develops non-invasive biosensor for early detection of kidney disease

Traditionally, kidney health has been monitored by measuring blood creatinine levels, which indicate muscle breakdown. High creatinine levels may suggest that your kidneys are not filtering waste products efficiently. However, creatinine levels can be affected by a person’s muscle mass and will only rise significantly if more than 75% of kidney function is lost.

Instead, SDMA, a byproduct of protein breakdown, has emerged as a more reliable indicator of kidney function. SDMA cannot be metabolized and is primarily excreted by the kidneys, so it accumulates in the bloodstream. Measuring SDMA in your urine can provide a more accurate indication of your kidney health. Unlike creatinine, SDMA levels increase even in the presence of mild renal impairment (25-40% decrease) and are not significantly affected by muscle mass.

In a recent study, researchers led by Professor Jong Pil Park from Korea Central University introduced a biosensor to detect SDMA levels in urine. This non-invasive method provides a reliable alternative to blood tests and allows for early detection and treatment of kidney disease. The study was published in the journal Biosensors and Bioelectronics.

“Kidney disease is often diagnosed very late, so we developed a sensing tool that patients and clinicians can use to easily monitor kidney health for effective treatment and provide timely treatment.” We aim to enable intervention and the possibility of long-term outcomes,” said Professor Park.

The core of this biosensor contains a small linear peptide that specifically binds to SDMA. These peptides were synthesized and attached to the surface of Ni-Cr layered double hydroxide with graphene oxide (NCL-GO) nanostructures and integrated onto a gold (Au) electrode.

To design the sensor, the researchers used a technique called drop-casting. They coated a gold electrode with a solution containing NCL-GO and dried it to form a stable coating of a peptide-functionalized electrode (termed peptide/NCL-GO/Au). The unique two-dimensional structure of NCL-GO is composed of Ni-Cr layered double hydroxide nanosheets interconnected with conductive graphene oxide nanosheets.

This setup forms a porous and well-connected network that promotes better charge transfer and molecular diffusion, increasing both the conductivity and surface area of ​​the electrode. This strengthens the interaction between the peptide and SDMA and improves the detection ability of the sensor.

Although other SDMA detection methods such as chromatography offer higher sensitivity, this new electrochemical biosensor is easy to use and does not require sophisticated equipment. This makes it more affordable and practical in many settings, including small clinics, remote areas, and low-resource locations. The simple design allows you to see results quickly, making it ideal for regular health checkups and monitoring.

“This sensor has the potential to facilitate early diagnosis, advanced monitoring of renal function, and improved treatment outcomes for millions of patients worldwide. Additionally, our platform technology could facilitate the detection of other biomarkers. “It has the potential to be adapted to many areas of medicine, making it a versatile tool that can be applied to many different areas of medicine,” says Professor Park.