Figure 2. Application force required for skin penetration.
(A) Force displacement curves generated during the application of microneedles to excised human skin. Force-displacement profiles were recorded for all microneedle applications (0.2–3N), up to a maximum force of 3N. (B,C) Methylene blue post-staining showing degree of skin penetration following microneedle application. (B) En face visualization of staining following skin puncture with varying force. (C) Quantification of lateral diffusion of the dye correlates microneedle application force with degree of skin penetration. Data presented as mean ± SD.