Dana J. DiScenza

Sensitive and selective detection of alcohols via fluorescence modulation

Abstract Reported herein is the selective detection of aliphatic alcohols using cyclodextrin-promoted, proximity-induced fluorescence modulation of a high-quantum yield fluorophore. This fluorescence modulation occurred when the analyte was held in close proximity to the fluorophore via non-covalent cyclodextrin–analyte–fluorophore interactions, and led to unique modulation responses for each analyte, fluorophore and cyclodextrin investigated. These changes in fluorescence were used for the generation of an array using linear discriminant analysis that successfully generated unique pattern identifiers for 99% of the investigated analytes, and could detect alcohols at micromolar concentrations. These results represent a fundamentally new detection approach for these challenging analytes, and have significant potential in the development of novel detection schemes.

Selective detection of non-aromatic pesticides via cyclodextrin-promoted fluorescence modulation

Reported herein is the detection of aliphatic pesticides using cyclodextrin-promoted fluorescence modulation. The introduction of the pesticide leads to noticeable changes in the emission of a fluorophore held in close proximity by cyclodextrin, leading to a pesticide detection system that operates with 100% successful differentiation and low limits of detection.

Cyclodextrin-Promoted Detection of Aromatic Toxicants and Toxicant Metabolites in Urine

Abstract Reported herein is the development of a fluorescence-based detection method for aromatic toxicants and toxicant metabolites in urine, using cyclodextrin-promoted energy transfer to high quantumyield fluorophores. This method distinguishes smoker urine from non-smoker urine, enables highly accurate analyte identification, and leads to micromolar detection limits.

Efficient fluorescence detection of aromatic toxicants and toxicant metabolites in human breast milk

Abstract Once chemical contaminants are released into the environment, there are a number of concerns that arise regarding the environmental persistence of the contaminants, their known and suspected toxicities, and their potential disruption to the ecosystem. One class of contaminants that is of continuing concern is polycyclic aromatic hydrocarbons (PAHs), persistent organic pollutants that are significant components of oil spills. PAHs have been found in the breast milk of nursing mothers living in oil spill-affected regions, and can harm the nursing children. We report herein the sensitive and selective detection of 10 PAHs and PAH metabolites in human breast milk using fluorescence energy transfer from the PAH to a high quantum yield fluorophore, and array-based statistical analyses of the resulting fluorescence responses. This detection system was able to separate and identify the PAHs with 100% success in human breast milk and at concentrations as low as 0.17 μM. These results have significant implications in public health and in the monitoring and mitigation of environmental disasters.

Detection of Organochlorine Pesticides in Contaminated Marine Environments via Cyclodextrin-Promoted Fluorescence Modulation

The development of practical and robust detection methods for pesticides is an important research objective owing to the known toxicity, carcinogenicity, and environmental persistence of these compounds. Pesticides have been found in bodies of water that are located near areas where pesticides are commonly used and easily spread to beaches, lakes, and rivers; affect the species living in those waterways; and harm humans who come into contact with or eat fish from such water. Reported herein is the rapid, sensitive, and selective detection of four organochlorine pesticides in a variety of water sources across the state of Rhode Island using cyclodextrin-promoted fluorescence detection. This method relies on the ability of cyclodextrin to promote analyte-specific fluorescence modulation of a high quantum yield fluorophore when a pesticide is in close proximity, combined with subsequent array-based statistical analyses of the measurable changes in the emission signals. This system operates with high sensitivity (low micromolar detection limits), selectivity (100% differentiation between structurally similar analytes), and general applicability (for different water samples with varying salinity and pH as well as for different water temperatures).

A highly versatile fluorenone-based macrocycle for the sensitive detection of polycyclic aromatic hydrocarbons and fluoride anions

Reported herein is the high yielding synthesis of a new fluorenone-based triazolophane and its sensing capabilities for polycyclic aromatic hydrocarbons (PAHs) and fluoride anions. Fluorescence, UV/Vis and 1H NMR spectroscopy results showed the triazolophane has a high sensitivity for selected PAHs and binds the fluoride anion in a 2 : 1 stoichiometry via C–H hydrogen bonding with the triazole and fluorenone protons.

Cyclodextrin-Promoted Fluorescence Detection of Aromatic Toxicants and Toxicant Metabolites in Commercial Milk Products

The detection of polycyclic aromatic hydrocarbons (PAHs) and their metabolites in food and in agricultural sources is an important research objective due to the PAHs’ known persistence, carcinogenicity, and toxicity. PAHs have been found in the milk of lactating cows and in the leaves and stems of plants grown in PAH-contaminated areas, thereby making their way into both cow milk and plant milk alternatives. Reported herein is the rapid, sensitive, and selective detection of 10 PAHs and PAH metabolites in a variety of cow milks and plant milk alternatives using fluorescence energy transfer from the PAH to a high quantum yield fluorophore, combined with subsequent array-based statistical analyses of the fluorescence emission signals. This system operates with high sensitivity (low micromolar detection limits), selectivity (100% differentiation even between structurally similar analytes), and general applicability (for both unmodified lipophilic PAHs and highly polar oxidized PAH metabolites, as well as for different cow and plant milk samples). These promising results show significant potential to be translated into solid-state devices for the rapid, sensitive, and selective detection of PAHs and their metabolites in complex, commercial food products.

Detection of bisphenol A and derivatives in human urine via cyclodextrin-promoted fluorescence modulation

Reported herein is the sensitive and selective detection of bisphenol A (BPA) and six BPA derivatives in buffer and urine environments. This detection system relies on the ability of γ-cyclodextrin to act as a supramolecular scaffold to promote highly analyte-specific, proximity-induced fluorescence modulation of high quantum yield fluorophores, which led to unique modulation responses for each cyclodextrin–analyte–fluorophore combination investigated in both buffer and urine environments, and high selectivity between structurally similar analytes using linear discriminant analysis of the resulting response signals. This method was sensitive (low micromolar detection limits), selective (able to differentiate between structurally similar analytes), and broadly applicable (with successful detection in both buffer and urine environments), and has significant potential in the detection of BPA and its derivatives in a wide variety of complex environments.

Efficient Detection of Phthalate Esters in Human Saliva via Fluorescence Spectroscopy

Abstract The detection of phthalates in human biologic fluids remains an important research objective because it provides an important measure of an individual’s exposure to this class of compounds, which have known deleterious health effects. Moreover, the ability to accomplish such detection in fluids that are easy to collect, such as saliva and urine, provides additional practical advantages. Reported herein is the application of cyclodextrin-promoted fluorescence energy transfer and fluorescence modulation to accomplish precisely such detection: the development of sensitive and selective florescence-based detection methods for phthalates in saliva, an easily collectable human biologic fluid. Such saliva-based detection methods occur with high levels of selectivity (100% differentiation) and sensitivity (limits of detection as low as 0.089 µM), and provide significant potential in the development of practical phthalate detection devices.

Array-based detection of isomeric and analogous analytes employing synthetically modified fluorophore attached β-cyclodextrin derivatives

Reported herein is a sensitive and selective array-based sensing strategy based on differential interactions with three supramolecular cyclodextrin–fluorophore sensors. Each interaction results in a distinct fluorescence modulation response, and linear discriminant analyses of these responses results in 100% successful classification of three classes of isomeric analytes and two classes of analogous analytes. Calculated limits of detection for this system are at or near literature-reported levels of concern.