The Contrasting Recognition Behavior of β-Cyclodextrin and Its Sulfobutylether Derivative towards 4',6-Diamidino-2-phenylindole.
The noncovalent interactions between 4', 6-diamidino-2-phenylindole (DAPI) and sulfobutylether β-cyclodextrin (SBE7β-CD) are evaluated by using photochemical measurements and compared with that of native β-CD. Contrasting recognition behavior and intriguing modulations in the photochemical behavior of DAPI were observed. In particular, a large enhancement in the fluorescence emission and excited-state lifetime were seen upon binding to SBE7β-CD, with the SBE7β-CD inclusion complex being approximately 1000 times stronger than that of β-CD. The ensuing fluorescence "turn on" was demonstrated to be responsive to chemical stimuli, such as metal ions and adamantylanmine (AD). Upon addition of Ca(2+)/AD, nearly quantitative dissociation of the complex was established to regenerate the free dye and result in fluorescence "turn off". The SO3(-) groups are believed to be critical for the strong and selective binding of the chromophore and the stimuli-responsive tuning. This is as an important design criterion for the optimization of host-guest properties through supramolecular association, which is relevant for drug-delivery applications.
Radiation & Photochemistry Division, Bhabha Atomic Research Centre, Mumbai, 400 085, India.|Student under BARC-SPPU PhD Program, Department of Chemistry, Savitribai Phule Pune University, Pune, 411007, India.
Meenakshi N
MN
Shinde
Radiation & Photochemistry Division, Bhabha Atomic Research Centre, Mumbai, 400 085, India.|Homi Bhabha National Institute, Anushaktinagar, Mumbai, 400 094, India.
Achikanath C
AC
Bhasikuttan
Radiation & Photochemistry Division, Bhabha Atomic Research Centre, Mumbai, 400 085, India. jyotim@barc.gov.in.|Homi Bhabha National Institute, Anushaktinagar, Mumbai, 400 094, India. jyotim@barc.gov.in.
Jyotirmayee
J
Mohanty
4′,6-diamidino-2-phenylindole; fluorescence; host-guest systems; photophysical properties; sulfobutylether β-cyclodextrin