Solid state physics is traditionally far away from medical applications, especially in a pharmaceutical context. Single crystalline solids have the reputation as unreactive and chemically less relevant materials. However, e.g., the II-VI semiconductor zinc oxide is known as biomedical and is as a traditional therapeutic described since more than 1000 years till today. Currently in pharmaceutical application, the dosage form is a nano particulate powder in ointments, known to be a mild antiseptic or employed as super hydrophilic, drying material. Limiting the application to the nano particulate form might results from the intention to from an increased surface area to dissolve Zn ions as an essential nutrient. Recent literature about the last 8 years reveals ideas that much more can be done with such solids. ZnO is reported to predominately kill cancer cells  or act as antiviral agent against HSV (Herpes simplex virus) . In the latter case, the mechanism is designed to be based on the oxygen vacancies on the surface of the single crystalline material. Glycoprotein groups on the herpes virion bind to the oxygen vacancies and trap in such way the virus and act as prophylactic, therapeudic and neutralizing agent . This feature is not limited to ZnO exclusively, similar semiconductors like SnO2 can be employed in a similar manner . Moreover, it was found that the micro tetrapod shape of the ZnO (T-ZnO ) mimics the function of a presenting cell, immobilized viral particles are rapidly taken up by dendritic cells . An immune response in animal studies could be found that is responsible for an unnatural high survival rate after treatment of HSV infected mice, the mechanism can provide a novel platform for live virus vaccine .
This unusual interaction of the dead solid state of ZnO in its tetrapodal crystalline form motivated recent experiments that utilize T-ZnO and related structures in the direction of regenerative medicine. The presentation will include results on latest experiments with the interaction with tissue, cells and bacteria and discuss the flexibility in structuring these templates with very high accessible porosity by 3D printing and combined top down and bottom up fabrication schemes.
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