Site-specific halloysite functionalization by polydopamine: A new synthetic route for potential near infrared-activated delivery system

Abstract Halloysite nanotubes (HNTs) represent a versatile core structure for the design of functional nanosystems of biomedical interest. However, the development of selective methodologies for the site-controlled functionalization of the nanotubes at specific sites is not an easy task. This study aims to accomplish a procedure for the site-selective/specific, “pin-point”, functionalization of HNTs with polydopamine (HNTs@PDA). This goal was achieved, at pH 6.5, by exploiting the basicity of ZnO nanoparticles anchored on the HNTs external surface (HNTs@ZnO) to induce a punctual polydopamine polymerization and coating. The morphology and the chemical composition of the nanomaterial was demo…