Report

Teaser, summary, work performed and final results

Periodic Reporting for period 1 - SCENT (SCENT: Hybrid Gels for Rapid Microbial Detection)

Teaser

Antimicrobial resistant bacteria are a global threat spreading at an alarming pace. They cause over 25,000 annual deaths in the EU, and represent an economic burden exceeding €1.5 billion a year. Current methods for microbial detection in clinical settings take about 24-36...

Summary

Antimicrobial resistant bacteria are a global threat spreading at an alarming pace. They cause over 25,000 annual deaths in the EU, and represent an economic burden exceeding €1.5 billion a year. Current methods for microbial detection in clinical settings take about 24-36 h, but for slow-growing bacteria, as those causing tuberculosis, it can take more than a week. Early-detection and confinement of the infected individuals are the only ways to provide adequate therapy and control infection spread. Thus, tools for rapid identification of bacterial infections are greatly needed.
The analysis of microbial volatile metabolites is an area of increasing interest in diagnostics. Recent works demonstrate that fast microbial identification is possible with chemical nose sensors. These sensors usually present limited stability and selectivity, and require aggressive conditions during processing and operation. Bioinspired nose sensors employing biological olfactory receptors are an alternative. Unfortunately, their complexity and low stability are a limitation. My group recently discovered a new class of stimulus-responsive gels which tackle these key challenges. Our gels are customisable and have a low environmental footprint associated. I intend to further explore their potential to advance the field of odour detection, while providing new tools for the scientific community. I will focus specifically in fast microbial detection. To accomplish this, I propose to 1) build libraries of hybrid gels with semi-selective and selective properties, 2) generate odorant specific peptides mimicking olfactory receptors, 3) fully characterise the gels, 4) assemble artificial noses for analysis of microbial volatiles, 5) create databases with organism-specific signal signatures, 6) identify pathogenic bacteria, including those with acquired antimicrobial-resistances. This project is a timely approach which will place Europe in the forefront of infectious disease control.

Work performed

Gels that smell

Can you imagine a gel that can distinguish different samples by smelling them? Roque and co-workers made this vision come true.

Roque and co-workers have developed gas-sensitive materials with a unique combination of biological and chemical components, which self-assemble to form a series of gels. These new materials mimic the biological olfactory system but are much simpler in composition and robust in their design. Gelatin fixes optical and ionic dopants, responsible for the dual optical and electrical signals of these materials in the presence of odors.

The gelatin gas sensing-materials were used in a tailor-made e-nose device, and tested to distinguish different volatile organic compounds, showing the potential for discrimination of distinct odors. Furthermore, a potential application was assessed towards the quantification of ethanol in automotive fuel.

Please check:
http://onlinelibrary.wiley.com/doi/10.1002/adfm.201700803/epdf

Final results

Detection of smells, or gas sensing, is becoming increasingly relevant in such diverse areas as medical diagnostics, manufacturing industry, security, environment, agricultural and food sciences. Electronic noses (e-noses) are devices used for gas sensing. These devices are able to distinguish gases by “smelling”, conceptually mimicking the biological olfactory system in humans and other animals. E-noses are comprised of an array of gas-sensitive materials that all have different and complementary selectivity thus, when considering the entire array, the e-nose gives rise to a pattern that is unique to the gaseous sample. These devices thereby mimic the set of biological receptors, which recognize odors in a combinatorial manner and are coupled to pattern recognition systems – mimicking signal processing analogous to that made by the brain – and are therefore capable of recognizing simple or complex odors.

The new materials developed within the SCENT project (http://onlinelibrary.wiley.com/doi/10.1002/adfm.201700803/epdf) are sensitive to both chemical and physical stimuli, several future applications can be envisaged compatible with miniaturized, wireless and wearable devices, from plastic electronics to electrochemical and medical devices.

Website & more info

More info: https://sites.fct.unl.pt/biomolecular_eng/pages/scent.