@misc{CaoLinMirsky, author = {Cao, Limin and Lin, Hong and Mirsky, Vladimir M.}, title = {DNA-based surface plasmon resonance biosensor for enrofloxacin}, series = {Analytica Chimica Acta}, volume = {589}, journal = {Analytica Chimica Acta}, number = {1}, issn = {0003-2670}, doi = {10.1016/j.aca.2007.02.034}, pages = {1 -- 5}, abstract = {A DNA-based surface plasmon resonance biosensor for enrofloxacin was developed. Heating denatured DNA immobilized on the gold-coated glass surface was exploited. The immobilization was performed by a layer-by-layer co-deposition with a cationic polymer. The sensor performance was tested with real biological probes. Direct and simple determination of enrofloxacin in milk samples was demonstrated. The sensor response obeys Langmuir binding isotherm being almost linear until about 20 µg per mL. The detection limit in milk samples was estimated to be 3 µg per mL.}, language = {en} } @misc{CaoLinMirsky, author = {Cao, Limin and Lin, Hong and Mirsky, Vladimir M.}, title = {Detection of antibiotics in food: Extraction of fluoroquinolones by DNA}, series = {Analytical and Bioanalytical Chemistry}, volume = {388}, journal = {Analytical and Bioanalytical Chemistry}, number = {1}, issn = {1618-2642}, doi = {10.1007/s00216-007-1191-5}, pages = {253 -- 258}, abstract = {The ability of DNA to extract fluoroquinolones from model solutions and real probes of food was demonstrated and investigated quantitatively. The interaction between fluoroquinolones and different types of DNA was studied by equilibrium dialysis. The first application of this direct approach allowed us to determine binding constants and binding stoichiometries in different conditions. The binding of enrofloxacin to heat-denatured DNA (d-DNA) from herring sperm is pH- and magnesium-dependent; the highest fraction of bound drugs was found at pH 7 and a magnesium concentration of 0.5-1 mM. Results for three types of DNA: d-DNA, double-stranded DNA and single-stranded DNA were compared. The unwound DNA showed almost doubled binding constants and stoichiometries, thus indicating preferable interaction of enrofloxacin with single-strand regions of DNA. The binding of other fluoroquinolones (lomefloxacin, ciprofloxacin, norfloxacin, danofloxacin and sarafloxacin) with d-DNA is very similar to that of enrofloxacin: the binding constants are in the range from 0.94 × 105 to 2.40 × 105 M-1, and the stoichiometries range from 4.1 to 6.9 fluoroquinolone molecules per 100 DNA bases. The binding properties were quantitatively the same for extraction of fluoroquinolones from model aqueous solutions and from liquid food (milk). The results indicate the efficiency of DNA for selective extraction of fluoroquinolones from real samples for further analysis. This selective binding also allows us to consider DNA as a natural receptor for development of analytical techniques for fluoroquinolones.}, language = {en} }