Fig. 4.

The effect of microneedle formulation and material on HA activity. HA activity of VLPs is shown after coating and dissolution in PBS. Coatings were made using a standard coating solution containing 15% trehalose and substituting CMC for various stabilizers (*p < 0.05 for comparison between xanthan gum and other viscous enhancers); b standard coating solution containing various carbohydrate stabilizers at a concentration of 15% (w/v) (*p < 0.05 for comparison between trehalose and other stabilizers); and c microneedles made from various materials as indicated in the figure legend using standard coating solution containing 15% trehalose (*p < 0.05 for comparison between stainless steel and other metals; n = 4, mean ± SEM)