A comparison between the responses of neutral red and acridine orange: acridine orange should be preferential and alternative to neutral red as a dye for the monitoring of contaminants by means of biological sensors.
The acridine orange (AO) and neutral red (NR) dyes, commonly used as probes to measure the internal pH in acidic vesicles, are compared in this article. The comparison between the two dyes (arising from calculations taking into account their analytical constants) illustrated that the use of AO is preferential to that of NR because the AO response is sensitive over the whole pH range between 4.0 and 7.4, whereas the NR response is effective only between pHs 4.0 and 6.0. In addition, it became evident from the mitochondrial respiration response that NR, unlike AO, is a protonophore. When taken into consideration, these two properties suggest that AO is more suitable than NR as an indicator of toxicity measurements in water samples because the environmental toxic compounds induce pH changes in the acidic vesicles of biological structures that are used as environmental biosensors.
Department of Environmental Sciences, Ca' Foscari University of Venice, Dorsoduro, Venice 30123, Italy.
Sabrina
S
Manente
Silvia
S
De Pieri
Alessandra
A
Iero
Chiarafrancesca
C
Rigo
Marcantonio
M
Bragadin
D000165:Acridine Orange / Q000737:chemistry*; D015374:Biosensing Techniques; D004396:Coloring Agents / Q000737:chemistry*; D004784:Environmental Monitoring / Q000379:methods*; D006863:Hydrogen-Ion Concentration; D008247:Lysosomes / Q000737:chemistry; D009499:Neutral Red / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000032:analysis* / Q000633:toxicity
D004396:Coloring Agents; D014874:Water Pollutants, Chemical; D009499:Neutral Red; D000165:Acridine Orange