Table 1.

Troubleshooting.

Step	Problem	Possible reason	Solution
1.8	Precipitate not visible	• pH of BBS solution is off • More NaPO4 required.	• Re-pH buffer • Spike mix with 1/100th volume Hyclone 1x PBS
1.8 (cont’d)	Precipitate too large	• Contaminants in DNA • Incubation time too long • Mixing method not optimized.	• EtOH Clean-up/Re-purify DNA • Examine aliquots at closer time intervals • Use an alternative method for combining Transfection Mix A & B
4.9	Difficulty re-suspending, capsid complexing with nucleic acid	• High titer capsids aggregate with themselves and contaminants inhibiting accurate QC analysis and transduction. To assess complexing, purified samples may be analyzed on SDS-PAGE and agarose gels.	• Suspension of PEG/NaCl and final pellet must be carried out in high osmotic buffers to prevent aggregation.