Fluorescein diacetate FDA

Other Names Fluorescein, diacetate 3, 6 -Diacetylfluorescein Huorescein 3, 6 -diacetate MFCD 

CA Index Name Spiro[isobenzofuran-l(3H),9 -[9H]xanthen]-3-one, 3, 6 - w(acetyloxy)-CAS Registry Number 596-09-8 Merck Index Number Not listed Chemical Structure 

Chemical/Dye Class Fluorescent, Xanthene Molecular Formula C24H16O7 Molecular Weight 416.38 pH Range 6.0-7.2 

Color Change at pH Weak green fluorescence (6.0) to strong green fluorescence (7.2) pKa 6.4 

Solubility Slightly soluble in water, ethanol soluble in methanol,, -dimethylformamide UV-Visible 490 nm 

---

Measurements other than respiration rate can also be used as indicators of soil microbial activity. These include measurements of the rate of multienzyme processes such as arginine ammonification rate (Alef and Kleiner 1995) fluorescein diacetate (FDA) hydrolysis rate (Alef 1995) and measurement of key endocellular enzymes such as dehydrogenase (Tabatabai 1994). 

The fate of nanoparticles has also been investigated in vivo. Albrecht et al. studied the in vivo mucoadhesive properties of thiomer formulations using magnetic resonance imaging and fluorescence detection (Albrecht et al. 2006). Following the hypothesis that unhydrated thiomers provide better mucoadhesion in vivo the group developed polycarbophil-cysteine microparticles loaded with fluoresceine diacetate (FDA) in Eutex capsules to maintain them in the dry... 

Fig. 9.1 Mucoadhesion studies amount of FDA remaining on the intestinal mucosa when applying fluoresceine diacetate (FDA) alone (grey bars), incorporated into chitosan nanoparticles (white bars) and into thiolated chitosan nanoparticles (black bars). Adapted from Bernkop-Schnurch et al. (2006)...

More recent staining procedures largely use fluorescent dyes to characterize the physiological and biochemical states of cells. Fluorescein Diacetate (FDA), a non-polar substance which crosses the membrane and is hydrolyzed by intracellular esterases in viable cells to produce fluorescein, exhibits yellow-green fluorescence when excited at 490 nm. Damaged or non-viable cells in general are unable to hydrolyze FDA or to retain fluorescein within the cell [172,173]. In combination with Ethidium Homodimer or Propidium Iodide, a similar esterase substrate, calcein acetoxy methyl ester (CAM) has been found to be reliable for viability assessment of protozoans, but not on Candida yeast, neither on bacteria such as Bacillus cereus and Escherichia coli [174]. 

Figure 18.3. Solubility of the dye fluorescein diacetate (FDA) in aqueous hydrotropic solutions as a function of the hydrotrope concentration at room temperature. Three different hydrotropes, i.e. sodium p-toluene sulfonate (NaPTS), sodium salicylate (NaS) and sodium butyl monoglycol sulfate (NaBMGS) were studied. (Reprinted with permission from Balasubramanian, D. et al., J. Phys. Chem., 93, 3865-3870 (1989). Copyright 2000 American Chemical Society)...

Adam, G. Duncan, H. Development of a sensitive and rapid method for the measurement of total microbial activity using fluorescein diacetate (FDA) in a range of soUs. Soil Biol. Biochem. 2001, 33, 943-951. 

Baek, S. H. Shin, K. Applicability of fluorescein diacetate (FDA) and calcein-AM to determine the viability of marine plankton. Ocean Polar Res. 2009,31,349-357. 

Alarcon-Gutierrez, E. Hoch, C. Ruaudel, F. Criquet, S. Non-enzymatic hydrolysis of fluorescein diacetate (FDA) in a Mediterranean oak (Quercus ilex L.) litter. Eur. J. Soil Sci. 2008,59,139-146. 

Chrost, R. J. Gajewski, A. Siuda, W. Fluorescein-diacetate (FDA) assay for determining microbial esterase activity in lake water. Adv. Limnol. 1999, 54, 167-183. 

---