RE: mRNA modifications to overcome stability and delivery issues
Try Mg2+ ions to neutralize negative charge of mRNA. Most nucleic acids exist in vivo as Mg2+ complexes, not just regular phosphate salts. However, the natural Mg2+ complexes may be more susceptible to RNAases! Use RNAase inhibitors, consider substituting Mn2+, or Zn2+, or Co2+, instead of Mg2+?