New technology to monitor diseases

Scientists have developed a device to facilitate monitoring of inherited metabolic and liver diseases.

The research and development team consists of specialists from the Autonomous University of Barcelona (UAB), Sant Joan de Déu Hospital and the Polytechnic University of Catalonia (UPC)

The new device makes it possible to monitor the amount of ammonia in the blood with the patient. The device, in the experimental phase, will facilitate the monitoring of liver diseases and other inherited metabolic diseases and may become a cheap alternative to current monitoring systems.

Ammonium is a biomarker used to diagnose different rare inherited metabolic diseases, such as primary urea cycle disorders and different organic acidemias, as well as other metabolic and environmental conditions that affect liver function with secondary urea cycle dysfunction. urea. It is also useful for the study and monitoring of different liver diseases (diseases that affect the normal functioning of the liver) caused by the consumption of alcohol or other substances of abuse, drugs and other environmental situations.

In all these diseases, an excess of ammonia is generated, which implies a risk to the patient’s health. Values ​​greater than 200 micromoles per liter of blood are considered serious episodes of hyperammonemia (high concentration of ammonia in the blood) that can cause irreversible neurological damage, and even death if they exceed 500 micromoles per liter. Therefore, early and real-time diagnosis is essential to minimize the impact of an episode of hyperammonemia on neurological functions. Currently, patients diagnosed with diseases that occur with hyperammonemia must periodically go to the reference hospital to have a blood draw that must be treated and analyzed in the laboratory.

Researchers from the Sensors and Biosensors Group (GSB) of the UAB Department of Chemistry, in collaboration with the Hospital Sant Joan de Déu and the UPC, have developed a Point-of-Care analyzer for monitoring ammonia in blood that will allow carry out decentralized measurements next to the patient, at the point of care, outside the analysis laboratories of hospitals where traditional equipment is used. The new device aims to decentralize the determination of ammonia, making it possible in smaller health centers with a measurement directly in the blood, without the need for any prior treatment. This means multiplying the follow-up points, simplifying the process and reducing the time for making medical decisions.

“Increasing the frequency of tests to determine the concentration of ammonia is of vital importance”, explains UAB researcher Mar Puyol, director of the study. “The reduction of excess ammonia in patients with hyperammonemia is done by restricting protein intake, using drugs to improve ammonia elimination or by dialysis or hemofiltration in acute cases, so that the patient’s evolution will be more favorable the sooner you act, and this is achieved with analyzers next to the patient like the one we have developed ».

The research team is fine-tuning a prototype so that it works in semi-autonomous conditions. Once it is operational, all the ammonium samples that are analyzed every day at the Sant Joan de Déu Hospital will be measured using the conventional method and with the new device developed. However, Puyol warns that “hundreds of samples will be necessary to be able to validate the final analyzer prototype. Subsequently, it must be industrialized to go to market. There are still several stages before reaching this stage, but it is expected to become a cheap device that facilitates the monitoring of liver diseases also in developing countries.

Antonio Calvo-López and Mar Puyol Bosch, researchers from the UAB Department of Chemistry, with the device, in the laboratory of the UAB Sensors and Biosensors Group. (Photo: UAB. CC BY-NC 4.0)

The device uses a microfluidic platform that integrates a potentiometric sensor as detection system and a gas separation membrane. In this way it is possible to automatically separate the ammonia in the form of ammonia from the rest of the complex matrix of the blood, obtaining a selective detection free of all kinds of interferents. This ensures a precise and exact determination of the ammonium concentration in whole blood and not in plasma, which is the medium where conventional analyzes of this parameter are carried out.

The research was directed by Julián Alonso-Chamarro and Mar Puyol Bosch, from the Sensors and Biosensors Group of the UAB Department of Chemistry. (Source: UAB)