Figure 1.
Microneedle vaccine delivery system. (A) Scanning electron micrograph of a microneedle (700 µm length, 160 µm width, 50 µm thickness; scale bar = 100 µm) (B) Comparison between an array of five microneedles and a human hair (scale bar = 500 µm) (C) Bright-field (i,iii) and fluorescence (ii,iv) micrographs of a microneedle coated with red-fluorescent inactivated influenza virus before (i,ii) and 10 min after (iii,iv) insertion into human cadaver skin (scale bar = 200µm). (D) Histologic section of human cadaver skin fixed after insertion of a vaccine-coated microneedle imaged by (i) bright-field microscopy with H&E staining showing skin deformation and needle track across the epidermis and into superficial dermis and (ii) fluorescence microscopy showing deposition of red-fluorescent vaccine coating in skin (scale bar = 200µm).