Highly selective and sensitive chiral recognition to deoxynucleosides by calixarene oligomers modified silver nanoparticles

Abstract

Efficient enantiomeric sensing to deoxynucleosides by a simple method is of great importantance and remains a challenge in biochemical field. In this paper, three chiral calixarene oligomers (CA[n]P, n=4, 6, 8) were synthesized and characterized by Fourier Transform Infrared Spectroscopy (FT-IR), UV–vis spectrophotometry, circular dichroism spectroscopy (CD), X-ray Powder Diff ;raction (XRD), X-ray Photoelectron Spectroscopy (XPS), Matrix Assisted Laser Desorption Ionization Time of Flight Mass Spectrometry (MALDI-TOF MS), 19F Nuclear Magnetic Resonance (NMR) and scanning electron microscopy (SEM). After that, the chiral calixarene oligomers capped silver nanoparticles (CA[n]P-Ag NPs, n=4, 6, 8) were prepared and characterized by FT-IR, UV–vis spectrophotometry, CD and dynamic light scattering (DLS). By using the as prepared CA[n]P-Ag NPs (n=4, 6, 8), highly selective and sensitive chiral recognition to deoxynucleosides was realized and demonstrated by UV–vis and CD. The color of the CAP-Ag NPs changes from yellow to red in the presence of β-L-2′-deoxycytidine (L-dC) or β-L-2′-deoxythymidine (L-dT) at a certain time, but not of their corresponding enantiomer β-D-2′-deoxycytidine (D-dC) or β-L-2′-deoxythymidine (D-dT). Moreover, the chiral recognition ability of CA[n]P-Ag NPs (n=4, 6, 8) toward L-deoxynucleosides was found to be in the order of CA[8]P-Ag NPs＞CA[6]P-Ag NPs＞CA[4]P-Ag NPs. This convenient method shows forceful prospect in developing biochemical sensors and has the potential application in enantiomeric recognition and separation of deoxynucleosides.