Delivering on the promise of RNA therapeutics

SiSaf is a biopharmaceutical company developing RNA therapeutics that are principally focused on rare genetic disorders.

We use innovative and proprietary bioabsorbable silicon-based Bio-Courier technology to facilitate superior delivery of nucleic acids for a wide range of targets and indications.

We are headquartered in Guildford, England with fully integrated state-of-the-art research labs, pilot manufacturing and bioanalytical facilities.

SiSaf is an RNA delivery and therapeutics company.

Our proprietary Bio-Courier® technology addresses the limitations of other RNA delivery technologies through the hybridization of organic materials with inorganic bioabsorbable silicon.

Our Pipeline

SiSaf is developing a growing pipeline of RNA therapeutics for rare diseases, and in particular skeletal disorders.

Osteopetrosis ADO2

Our lead program is focused on autosomal dominant Osteopetrosis Type II, also known as marble bone disease.


Our second program is targeting Achondroplasia which is characterized by drastically reduced bone growth in pediatric patients and dwarfism.

Pancreatic Cancer

We are in the process of expanding our pipeline into oncological applications and are developing a miRNA therapy for solid tumors, with the initial indication being pancreatic cancer.

Our Enabling Technology

Chemical structure of Bio-Courier

SiSaf’s Bio-Courier technology combines a bioabsorbable silicon matrix with lipids and amino acids, a structure that addresses several of the major limitations and concerns associated with lipid nanoparticles (LNPs) to deliver RNA therapeutics.

Unlike conventional lipid nanoparticles, Bio-Courier particles can be manufactured empty and loaded with the RNA later, at the desired point and time of use.

Not only does this enable local manufacturing but there is no need for an ultra-cold supply chain.

Chemical structure of Bio-Courier