Sunday, 15 April 2018

New Microsensor Enables Kidney Dialysis to be Customized to the Patient's Needs

It's nice to have the personal touch when having dialysis. Having your doctor or nurse set things up to better match your needs. But new research goes a step further than that.

Researchers from TU Eindhoven have developed a microsensor that makes it possible to directly monitor and adjust the composition of kidney dialysis fluid. This is a crucial step towards patient-specific dialysis, which will remove a significant proportion of the serious side effects of the use of standard dialysis fluid. And on 29 March 2018, Manoj Kumar Sharma will be awarded a PhD for his research on this sensor.

The number of patients worldwide on dialysis is quite astonishing - 2 million people are being treated just now.

Salts and impurities in the blood are removed via the dialysate fluid, passing through a membrane into the fluid. The rate of flow is dependant on the concentration difference between the blood and the dialysate. And the concentration in the blood varies from patient to patient. It doesn't help that the dialysate is supplied at a standard concentration, not tailored to each patient (and the patient's needs would be different at each session. There are side effects if the mismatch in concentrations is too high or too low.

It would be better to continuously adjust the concentrations of salts in the dialysate so that they are optimal for the patient. This, however, requires that the concentrations of salts in the dialysate can be monitored live, but there has not been a reliable technique to do this so far.

But now things are changing for the better.

PH D student Manoj Kumar Sharma has devised an ingenious solution for this. He developed a micro-system with a centrally positioned microchannel through which dialysate flows. He covered the walls of the microchannel with sensor molecules, which are only fluorescent in the presence of a salt, such as sodium. The more sodium there is in the dialysate, the stronger the fluorescence. To reinforce this effect, he introduced micropillars into the microchannel, resulting in even more surface covered with sensor molecules.

A laser light shines on the microchannel and activates the fluorescence of the sensor molecules. Sharma captures this fluorescence using glass fibres that he connected to the channel in the micro-system. The light passes through the fibres to a spectrometer for analysis. The laser light, which is of a different wavelength, is first filtered out. Then, based on the measured intensity of the fluorescence, the sodium concentrations can be read out.

If the sensors and monitoring system can be mass produced and used on a large scale, built into dialysis machines, one day each patient will receive during their dialysis session a customised dialysate to match their needs, the concentration changing to suit the current state of their blood.

Visit the University website to read the full article on this exciting development.