Acta Phys. -Chim. Sin. ›› 2001, Vol. 17 ›› Issue (03): 222-228.doi: 10.3866/PKU.WHXB20010307

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Spectra of the Supramolecular Interaction of Neutral Red with Doublestranded DNA in a Neutral Medium

Huang Cheng-Zhi;Li Yuan-Fang;Huang Xin-Hua;Feng Ping   

  1. Institute of Environmental Chemistry, Southwest Normal University, Chongqing 400715
  • Received:2000-07-22 Revised:2000-11-20 Published:2001-03-15
  • Contact: Huang Cheng-Zhi

Abstract: With the spectral measurements of molecular absorption, fluorescence, and resonance light scattering, the binding mode of neutral red (NR) with double stranded DNA has been characterized in a neutral aqueous medium. Depending on t he molar ratio R of NR: DNA, it was found that the binding involves in two proce sses at pH 7.63 and ionic strength lower than 0.01. The first process occurs in R > 2.22, where enhanced resonance light scattering was found, indicating the ag gregation of NR molecules on the molecular surface of double stranded DNA. Scatc hard plot was used to discuss the aggregation features based on the measurements of RLS data. The second process occurs in R < 2.22, characterized by bathochrom ic and hyperchromic molecular absorption of the interacting system, indicating t he intercalative binding of NR into the base pairs of the double stranded DNA mo lecules. Energy transfer from DNA to NR molecules in the second interacting proc ess occurs, resulting in strong enhancement of fluorescence, which proves NR can be used as a fluorescent probe as DNA structure.

Key words: Neutral red, DNA, Molecular absorption, Fluorescence, Resonancel ight scattering