Exploring the retention properties of CaF2 nanoparticles as possible additives for dental care application with tapping-mode atomic force microscope in liquid

Matthias Wasem,Joachim Köser,Ernst Meyer,Sylvia Hess,Enrico Gnecco

doi:10.3762/bjnano.5.4

Abstract

Amplitude-modulation atomic force microscopy (AM-AFM) is used to determine the retention properties of CaF2 nanoparticles adsorbed on mica and on tooth enamel in liquid. From the phase-lag of the forced cantilever oscillation the local energy dissipation at the detachment point of the nanoparticle was determined. This enabled us to compare different as-synthesized CaF2 nanoparticles that vary in shape, size and surface structure. CaF2 nanoparticles are candidates for additives in dental care products as they could serve as fluorine-releasing containers preventing caries during a cariogenic acid attack on the teeth. We show that the adherence of the nanoparticles is increased on the enamel substrate compared to mica, independently of the substrate roughness, morphology and size of the particles.

Highlights

Amplitude-modulation atomic force microscopy (AM-AFM), known as tapping mode AFM, is a variant of scanning probe microscopy
In this study we focus on exploring the adhesion strength of calcium fluoride nanoparticles adsorbed on mica and on tooth enamel in liquid with AM-AFM
The frequency distribution of the calculated power dissipated for each of the particles enables us to examine the chemical affinity between the calcium fluoride nanoparticles adsorbed on mica and on polished tooth enamel

Summary

Introduction

Amplitude-modulation atomic force microscopy (AM-AFM), known as tapping mode AFM, is a variant of scanning probe microscopy. In this work we show that for surface associated manipulation of nanoparticles in liquid, the phase-lag in AM-AFM is closely related to the retention properties of the adsorbed nanoparticles, i.e., the particle–substrate contact area and the intrinsic chemical affinity between them. This enabled us to qualitatively compare the adhesion strength of as-synthesized CaF2 nanoparticles adsorbed on mica and on tooth enamel in liquid.

Results

Conclusion