Leveraging Material Properties in Fluorescence Anion Sensor Arrays: A General Approach

Abstract

As the demand for probes suitable for sensor development increases, investigation of approaches that utilize known successful receptors gains in general importance. This study describes a two-prong approach that can be used as a guide to developing sensors from known receptors. First, the conversion of a simple receptor, calix[4]pyrrole, into a fluorescent probe to establish a ratiometric signal is described. Secondly, the sensors that employ an output from a single ratiometric calix[4]pyrrole probe are fabricated by using poly(ether-urethane) hydrogel copolymers. These hydrogels are designed to absorb, internalize and transport aqueous electrolytes. A sensor array of ten different poly(ether-urethane) matrices with varying comonomer proportions were doped with a single probe and were exposed to eight different anions: acetate, benzoate, fluoride, chloride, phosphate, pyrophosphate, hydrogen sulfide, and cyanide, eight urine samples and anti-inflammatory drugs (NSAIDs). The poly(ether-urethane) matrices comprise different proportions of anion-binding urethane moieties and different hydrophilicity given by the ratio between ethylene glycol ether and butylene glycol ether. This diversity in the hydration behavior provides different environment polarity, in which the recognition and self-assembly processes display enough diverse behavior to allow for unique response of the probe to the analytes. Furthermore, a single probe is shown to recognize eight different aqueous anions and eight urine samples when embedded in ten different polyurethanes in an array that displays 100 % classification accuracy. To demonstrate the potential of the concept for quantitative studies, an estimation of non-steroidal anti-inflammatory drugs ibuprofen and diclofenac in water and in saliva was performed. A limit of detection of 0.1 ppm and a dynamic range of 0.1-0.6 and 0.05-60 ppm was observed, respectively. Given the general difficulty of chemosensors to recognize aqueous anions, the fact that one probe recognizes eight different analytes attests to an enormous effect of the polymer environment on the recognition process. This method could be used to generate a variety of sensor arrays for various analyses including species that are difficult to recognize, such as small-molecule- and inorganic anions.

Porphyrin-based sensor nanoarchitectonics in diverse physical detection modes

“…Anzenbacher et al developed a fluorescent probe molecule based on an octamethylcalix[4]pyrrole structure that is capable of anion binding while displaying an anion-specific change in fluorescence. 47 Doping into poly(ether-urethane) matrices leads to ion-selective optodes operating with a co-extraction mechanism. Neves, Lodeiro and coworkers synthesized new corrole derivatives that showed sensing ability towards the spherical halide ions F À , Cl À , Br À , and I À , the linear anion CN À and the bulky anions CH 3 COO À and H 2 PO 4 À .…”

Art, auto-mechanics, and supramolecular chemistry. A merging of hobbies and career

“…While the miniature nature of the system was intriguing, such a device was going to be difficult for supramolecular chemists to adopt. More user-friendly variants for spatially arraying receptors for solution analysis were thus created by others, such as Pavel Anzenbacher’s sol–gel approach [ 95 – 96 ]. Yet, the absolute easiest way to array receptors is to use commercially available plates, such as plastic 96-well plates, because the receptors can be dissolved and then dispensed by common 8- and 12-channel pipettes.…”

A Fluorescent Sensor Array Based on Heteroatomic Macrocyclic Fluorophores for the Detection of Polluting Species in Natural Water Samples

“…However, only few examples of multisensory fluorescent systems for analysis of anions are reported (Anzenbacher et al, 2013 ; Lin et al, 2015 ; Pushina and Anzenbacher, 2017 ). Thus, for instance a fluorescent sensor array based on supramolecular metallogels for the identification of CN − , SCN − , S 2− and I − anions in water was reported by Lin et al ( 2015 ).…”

“…The aqueous solutions of 11 different analytes were correctly identified with LDA analysis. Anzenbacher et al have also reported an anion-sensitive array based on a ratiometric calix[4]pyrrole introduced in poly(ether-urethane) hydrogel matrices with varying comonomer proportions (Anzenbacher et al, 2013 ). This array was used to discriminate eight different anions (acetate, benzoate, fluoride, chloride, phosphate, pyrophosphate, hydrogen sulfide, and cyanide) in urine samples and anti-inflammatory drugs with 100% classification accuracy.…”