Directly created electrostatic micro-domains on hydroxyapatite: probing with a Kelvin Force probe and a protein

TL;DR

This study demonstrates the creation of micro-domains with modified surface potential on hydroxyapatite films using focused electron beam patterning, and investigates their properties through Kelvin Force Microscopy and protein adsorption analysis.

Contribution

It introduces a method for directly patterning electrostatic micro-domains on hydroxyapatite and characterizes their surface potential and protein interaction properties.

Findings

SP patterns match lysozyme adsorption distribution

Micro-domains created with focused electron beam

Surface potential can be probed at sub-micrometer scale

Abstract

Micro-domains of modified surface potential (SP) were created on hydroxyapatite (HAp) films by direct patterning by midenergy focused electron beam, typically available as a microprobe of Scanning Electron Microscopes. The SP distribution of these patterns has been studied on sub-micrometer scale by the Kelvin Probe Force Microscopy method as well as lysozyme adsorption. Since the lysozyme is positively charged at physiological pH, it allows us to track positively and negatively charged areas of the SP patterns. Distribution of the adsorbed proteins over the domains was in good agreement with the observed SP patterns.