Viral vectors
What I tried: I injected AAV9-hSyn-EGFP (from Penn) into the plantar hindpaw of adult mice. The virus was 10^13 vg/ml. I injected 10 ul. I saw some (~10%) transduction in the L4 DRG after injection 3 weeks later. It wasn’t impressive.
Thoughts: AAV9 is known to retrogradely transport, but the efficiency is probably low. There is likely more infection that I can detect with fluorescence microscopy, but the expression is too low to be noticeable. Other serotypes such as AAV6 may be better for certain DRG neuron types (small).