Professor McMillans research focuses on treatments for viruses and viral cancers.  He discovered the receptor for the human papillomavirus, has developed RNA-based treatments for viral cancers, and has developed nanoparticle delivery systems for gene silencing and editing therapy. His laboratory was the first to show cancer could be cured in vivo using CRISPR (2019) and that siRNAs would cure animals from COVID19 infection (2021).  

His patents have been licensed to international biotechnology companies and his labs work on a nanoparticle-delivered gene silencing therapy for COVID-19 disease was recently licenced to The Gene Company for $135m.  His laboratory is currently developing second generation lipid nanoparticles using biomimetics of natural particles like extracellular vesicles.  He heads the Griffith Centre for Cell and Gene Medicines, which includes the Griffith Nanoparticle Biofoundry and is Professor in the School of Pharmacy and Medical Sciences and Associate Director of the Institute for Biomedicine and Glycomics at Griffith University