Recruiting Algae To Fight Cancer

Porous silica particles hold great promise as drug delivery vehicles, thanks to their stability, biocompatibility, and chemical inertness. Unfortunately, these particles can be expensive to synthesize and require toxic chemicals, such as hydrofluoric acid, to make their all-important pores. But making porous silica particles is easy for the unicellular algae known as diatoms. These microorganisms have a porous cell wall that’s made of silica, giving them the nickname “algae that live in glass houses.” Researchers led by Nicolas H. Voelcker of the University of South Australia and Nils Kröger of Dresden University of Technology have taken these silica skeletons and tweaked them to target cancer cells (Nat. Commun. 2015, DOI: 10.1038/ncomms9791). The scientists genetically engineered the diatom Thalassiosira pseudonana to produce the immunoglobulin G-binding domain of protein G on its surface. This handle allows them to attach antibodies that target specific cancer cells. After the scientists evict the algae from its skeleton, they load the particle with cancer-fighting drugs. The researchers showed the antibody-armed particles selectively kill neuroblastoma and B-lymphoma cells in vitro and reduce the size of neuroblastoma tumors in mice.