Evaluating the use of 3'-(p-Aminophenyl) fluorescein for determining the formation of highly reactive oxygen species in particle suspensions

<p>Abstract</p> <p>Background</p> <p>Given the importance of highly reactive oxygen species (hROS) as reactants in a wide range of biological, photochemical, and environmental systems there is an interest in detection and quantification of these species. The extreme reactivity of the hROS, which includes hydroxyl radicals, presents an analytical challenge. 3'-(<it>p</it>-Aminophenyl) fluorescein (APF) is a relatively new probe used for measuring hROS. Here, we further evaluate the use of APF as a method for the detection of hydroxyl radicals in particle suspensions.</p> <p>Results</p> <p>Particle-generated hROS can be quantified with an estimated detection limit of 50 nM. Measurements of hROS in two National Institute of Standards and Technology (NIST 2709 and 2710) soil suspensions and a pyrite suspension show non-linear particle dose-response curves for hROS generation. APF can also be used in solutions containing no dissolved molecular oxygen (O₂) to determine the role of O₂in the formation of hROS. Results confirm that O₂is mechanistically important in the formation of hROS by dissolved ferrous iron and in pyrite suspensions.</p> <p>Conclusion</p> <p>Given the non-linear dose-response curves for particle generation of hROS, we recommend using several particle loadings in experiments aimed to compare particles for their hROS generation potential. The method presented here is specific to hROS and simple to perform. The analysis can be conducted in mobile labs as only basic laboratory equipment is required.</p

Development of an Online Fluorescence Method for near real time in vivo monitoring of Hydroxyl Radicals in rats

Hydroxyl radicals have been implicated in the etiology of many diseases, therefore on line monitoring of hROS should be extremely helpful to further investigate and understand the role of hROS in the pathogenesis of neurological disorders and to develop medical strategies to reduce the damaging potential of hROS. Furthermore, while the use of the HPLC is limited in terms of time resolution (sampling time could not be reduced below 10 min) the on line system allows real-time measurements, which is crucial for understanding the chemical events involved in physiological and pathological processes. Therefore, the main emphasis of this work was to investigate hROS in vivo on line by using a simple and well characterized animal model of excitotoxic damage based on the application of a high concentration (1 mM and 500μM) of the non-NMDA glutamate receptor agonist, kainate (KA), to the neostriatum in freely moving animals through the dialysis probe. For this purpose a highly sensitive fluorescence detector equipped with a capillary flow cell, coupled directly to the rat striatal microdialysis system, was successfully developed and employed for continuous on line determination of hROS under in vivo conditions. Comparing with the HPLC or other analytical methods which are used for hROS detection, the presented method has provided significant advantages in terms of its sensitivity and simplicity. Further, due to its better temporal resolution and high precision, this method could find a wide application in understanding of hROS chemical events involved in some physiological and pathological processes and might also lead to a human application