Detection of Non-nitro Compounds by Amplified Fluorescence Polymer (AFP): An Opportunity for Breath-Based Disease Diagnosis

Abstract

Amplified fluorescence polymers (AFP) are a set of unique polymers known for their ability to detect trace nitro explosives. The prior knowledge in the AFP field indicates that the functional group variation on the polymer backbone is responsible for the selectivity of an analyte. The mechanism of analyte detection is believed that only compounds with nitro functional groups are detected by AFP. Usually, AFP functional groups varied to detect nitro compounds and the non-nitro compound detection and the mechanism of the AFP were not completely understood. In this work, the AFP polymer was kept constant and studied with 136 analytes with different functional groups for analyzing few non-nitro compounds. Among the 136 compounds analyzed, about fourteen have been detected by AFP. It was observed that most of the fourteen compounds were non-nitro compounds. The mechanism proposed originally for nitro compounds and associated hypothesises the existence of a parking space on the polymer backbone. Present study suggested that the possibility of only nitro compounds interacting with AFP due to the three-dimensional shape of the analyte as the detrimental factor. The discovery of non-nitro compound detection by AFP opens up the use of AFP for gas-phase disease volatile organic compound detection. Future studies of functional group variation on the AFP backbone in relation to the analyte detection could provide insights into the relation of analyte detection by AFP and the parameters to optimize for obtaining the selectivity and specificity.