Beyond hepatic delivery with GalNAc, what ligand technologies hold the most promise (e.g. antibodies, peptides, lipids, etc) to unlock new tissues/cell types?

Where do you see the largest space for optimizing the targeted delivery of oligonucleotide? 

How can AI/ML help us transition from brute-force screening to a rational Design-Build-Test-Learn cycle that accurately predicts biodistribution and tissue tropism? 

What factors contribute to pursuing a novel delivery technology vs. a clinically validated technology? 

What are the biggest hurdles for siRNA-based therapeutic delivery?