Catching Strays: Methods for Detecting Invisible Forever Chemicals

PFAS (per/polyfluoroalkyl substances) encompass a group of roughly 12,000 man-made chemicals that are so stable that they have been tokened with the title “forever chemicals.” Because of its widespread use and slow degradation, PFAS exists practically everywhere in the environment. Concerningly, consumption of PFAS compounds due to environmental contamination has been correlated with many illnesses, prompting research into detection methods for PFAS to limit exposure in the general population. Current analytical methods for detecting PFAS are either time consuming and expensive or lack sensitivity and selectivity. To mitigate these limitations, we hypothesize that functional nucleic acid (FNA) technology can be used to develop sensors for on-site PFAS detection. Within the broader class of FNAs there is a class known as aptamers, which are short single stranded DNA or RNA molecules that display binding affinity to a selected compound or class of compounds. We plan to use SELEX, or Selective Evolution of Ligands for Exponential Enrichment, to identify novel aptamer sequence candidates with ligand binding specificity to selected PFAS compounds. We believe that compiling multiple aptamer sensors, each selective to a specific PFAS compound, could be utilized to design a pattern based detection array to identify both the concentration and identity of the contaminating PFAS compound in applicable samples. 

1. Use a combination of PCR and Gel Electrophoresis to determine optimal number of cycles for aptamer selection

2. Utilize affinity chromatography for the selection of candidate aptamers

3. Utilize large-scale PCR for amplification of desired DNA sequences

• SELEX Chromatography was successful in amplification of DNA sequences that bound to the positive selection, but not the negative selection

• Further research which has been started must be done to determine whether or not aptamers using these sequences will be able to fluoresce upon binding with the appropriate PFAS

• This further research has been started by our lab, and has shown promise for selection of larger-chain PFAS, however this is further than the scope of this section of the project

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