Daniel Hoffelner wrote his thesis about the template assisted synthesis of Janus-type functionalised particles. The whole research group Mathur congratulates him to his successful defense.

Abstract

Janus-type particles which combine the specific properties of different materials are currently gaining great interest in research due to their side selective surface functionalisation. These asymmetric particles can hence be used in a wide range of potential applications including biomedicine.

However, to date synthesis protocols are limited in the usage of chemicals and an easy, controllable and flexible step by step approach for the design of Janus-type functionalised particles is still missing. In this approach, a reproducible and cheap method for designing gold covered silica particles with asymmetric chemical functionalities is reported. In more detail, functionalised silica particles were prepared, dried on a substrate and finally covered with gold by sputtering. Several specific functionalities were attached to the silica side including amino, thiol and azide groups for potential carbodiimide, disulfide or click reactions, respectively. The presence of these groups on the particle surface was demonstrated by Raman and FTIR spectroscopy as well as XPS, DLS and zeta-potential measurements. After Au sputtering, SEM and TEM analysis proved the successful synthesis of uniform Janus-type spheres.

The as-described method allows tuning of the particle properties depending on the de-sired application. For instance, by attaching a thiolated biomarker onto the gold surface and linking a drug e.g. via click chemistry to the silica side, highly selective drug delivery vehicles could be prepared.