Reinventing infection diagnostics: speed, affordability and patient proximity

In clinical practice, time is of critical importance: the sooner the pathogen responsible for an infection is identified and its resistance genes detected, the greater the chance of initiating targeted therapy. Today’s standard molecular diagnostic methods are highly effective, but they often require expensive equipment, complex optical systems and work carried out in specialised laboratories. This limits access to rapid, point of care diagnostics.

“Within the framework of the project, we are developing a miniaturised, multifield detection module for identifying nucleic acids (DNA) using electrochemical methods, designed as a component of future portable point of care (PoC) systems,” says Prof. Robert Ziółkowski from the Faculty of Chemistry at Warsaw University of Technology, the project leader. “Instead of conventional fluorescence readouts, we measure very small changes in the electrochemical signal on the surface of the electrodes. This approach can significantly simplify the device architecture, facilitate miniaturisation and reduce the cost of each individual test.”

Low-cost‑ substrates: printed electronics on foil

One of the core components of the project is the development and use of multifield electrochemical transducers manufactured using printed electronics technologies on flexible substrates (polymer foils), with metallic elements produced using vacuum based methods (e.g. screen printing, PVD), among others. This technological pathway is scalable and compatible with large volume production, while at the same time enabling the fabrication of reproducible, miniaturised measurement fields. This is crucial, because diagnostics requires not only sensitivity but also stability and signal reproducibility from one test to the next.

Multiplexing and multi‑field detection: several markers in a single measurement

The multi‑field architecture of the sensor means that a single transducer contains several independent measurement sites, each capable of detecting a different genetic marker. This enables the simultaneous analysis of multiple analytes (multiplexing) – for example, the parallel detection of markers identifying the pathogen and genes responsible for antibiotic resistance. Such a format reflects the real needs of infection diagnostics, where a “one marker – one decision” result is often insufficient, and rapid, multi‑parameter information is of especially valuable.

Multifield electrochemical transducers developed within the project are designed for rapid and reliable genetic analyses in unpurified, real-world samples

Custom-made enzymes: DNA amplification in challenging samples

The second key area of the project focuses on the development and use of custom-made enzymes (including fusion polymerases) designed to facilitate the amplification of target DNA sequences under challenging conditions – situations in which conventional reactions are inhibited by substances naturally present in clinical samples. These enzymes make it possible to move closer to the intended scenario in which analysis is faster and simpler, with fewer sample preparation steps required.

Detection without largescale optics and with operation closer to real-world samples

The key advantage of electrochemistry is that the detection signal does not require complex optical modules. Moreover, electrochemical readout can be designed to operate in complex matrices, including unpurified or postreaction samples, where conventional fluorescence-based approaches are often limited by background and autofluorescence. In the project, the researchers focus on refining the biosensor’s receptor layers (self-assembled monolayers, SAM) and the assay conditions, so that selectivity, repeatability and signal stability are maintained during measurements performed on unpurified real-world samples.

Research infrastructure as an investment in high-quality and reliable results

An important outcome of the project is the strengthening of the research infrastructure. Thanks to the funding, the team was able to acquire the Prometheus Panta (NanoTemper) device – a modern platform for protein characterisation, including conformational stability and aggregation propensity. This enables better optimisation of buffer conditions and additives for the biological components used in the analyses, as well as more informed procedure design. These improvements directly enhance the repeatability and reliability of the developed solution and ultimately influence, among other factors, the total time required to complete a full analysis.

Where is this work taking us?

The aim of the work is to bring the technology to the demonstrator stage: a multi‑field, miniaturised detection module that will showcase the simultaneous analysis of multiple markers and will be ready for further integration into portable PoC systems. The technology under development addresses real healthcare needs, since faster identification of pathogens and resistance genes leads to better therapeutic decisions, reduced unnecessary use of antibiotics and more effective action against antimicrobial resistance.

The research is carried out as part of the project titled “Development of modern infection diagnostics based on electrochemical sensor arrays as detection elements for portable, low-cost PoC devices dedicated to rapid and reliable genetic analyses”, funded by the Medical Research Agency.

The project is led by Prof. Robert Ziółkowski.

The research team includes:

• Dr Marcin Drozd, Prof. Marcin Olszewski, Dr Katarzyna Szymańska, Dr Aleksandra Tobolska and Dr Nina Wezynfeld – from the Faculty of Chemistry at Warsaw University of Technology,
• Dr Jakub Krzemiński – from the Centre for Advanced Materials and Technologies at Warsaw University of Technology,
• Prof. Aleksandra Zasada, MD,
• Dr Maciej Polak, MD,
• Melania Klara Cynke, Klaudia Marlicka, Katarzyna Serafin and Aleksandra Julia Skiba – PhD candidates from the Doctoral School at Warsaw University of Technology,
• Maria Boulaguigue, Dominika Dobrowolska, Wiktoria Miklińska, Radosław Pytlarz and Julia Szeptycka – students from the Faculty of Chemistry at Warsaw University of Technology.