New DNA-sensor based on thiacalix[4]arene-modified polydiacetylene particles

Abstract

New p-tert-butyl thiacalix[4]arene derivative in the 1,3-alternate stereoisomeric form containing two diethylenetriamine groups and pentacosa-10,12-diynoic moieties on the opposide sides of macrocyclic cavity was synthesized using the copper(i)-catalyzed azide-alkyne cycloaddition. According to the dynamic and electrophoretic light scattering data, the synthesized macrocycle forms submicron particles with the sizes 200 nm and ζ-potential equal to 43 mV. The critical aggregation concentration of the macrocycle was 0.019 mmol L⁻¹. The obtained macrocycle intercalates into calf thymus DNA (CT DNA) to form a lipoplex. Using ethidium bromide as a fluorescent probe intercalation of obtained macrocycle into CT DNA with following formation of a lipoplex with the ζ-potential equal to −30 mV was found. The macrocycle was used for the synthesis of mixed polydiacetylene particles with N-(2-aminoethyl)pentacosa-10,12-diynamide (PCDA) as a base lipid. The highest degree of polymerization is achieved in the system with the macrocycle to PCDA ratio equal to 1 : 4. Macrocycle embedding into the polydiacetylene particles significantly increases their colorimetric response to CT DNA. The response to CT DNA as a change in the color of a solution of particles from blue to red is seen by naked eye at the CT DNA concentration starting from 20 µmol L₋₁, which makes the obtained particles promising for bioanalytical application.