Electrosteric stabilization of colloidal TiO2 nanoparticles with DNA and polyethylene glycol for selective enhancement of UV detection sensitivity in capillary electrophoresis analysis

Abstract

A new approach to selectively enhance the ultraviolet (UV) detection sensitivity of titania (TiO₂), albeit in the presence of silica (SiO₂), alumina (Al₂O₃), and zinc oxide (ZnO), nanoparticles in capillary electrophoresis (CE) analysis was developed. Interactions of Triton X-100 (TX-100), polyethylene glycol (PEG), and deoxyribonucleic acid (DNA) with TiO₂ nanoparticles produced larger CE-UV peaks at various enhancement factors. Single-stranded DNA (ssDNA) was a more effective adsorbate than double-stranded DNA (dsDNA) due to its flexible molecular structure that participated in a stronger interaction with TiO₂ nanoparticles via its sugar-phosphate backbone. Disaggregation of TiO₂ nanoparticles upon DNA binding due to electrosteric stabilization was validated using dynamic light scattering. PEG coating of TiO₂-DNA nanoparticles further enhanced the UV detection sensitivity in CE analysis by providing extra electrosteric stabilization. This analytical technique, which involves binding of TiO₂ nanoparticles with DNA followed by coating with PEG, has allowed us to achieve progressively an enhancement factor up to 13.0 ± 3.0 - fold in analytical sensitivity for the accurate determination of disaggregated TiO₂ nanoparticles. Graphical Abstract Selective enhancement of UV detection sensitivity for TiO₂ nanoparticles via electrosteric stabilization using ssDNA and PEG.

Keywords: Deoxyribonucleic acid; Disaggregation; Electrosteric stabilization; Polyethylene glycol; Titanium dioxide; Triton X-100.