Characterization of dissolvable microneedle arrays loaded with DNA (N:(P)0) and RALA/DNA nanoparticles (N:(P)10). (A) Digital microscope images of microneedles formulated from i) 360 kDa PVP, ii) 58 kDa PVP, iii) 13–23 kDa PVA and iv) 9–10 kDa PVA loaded with RALA/DNA nanoparticles (N:P 10) prior to and (B) following 45 N axial compression; (C) Percentage height reduction of i) 360 kDa PVP, ii) 58 kDa PVP, iii) 13–23 kDa PVA and iv) 9–10 kDa PVA arrays, unloaded or loaded with DNA only(N:P 0) or RALA/DNA nanoparticles (N:P 10) following 45 N compression (means + SEM, N = 3).