Fig. 2. Confocal microscopy images (λex = 405 nm) from 20 and 4 μm beyond the surface of (a) DI-PBS-1.0 and (b) SP-PBS-0.7, respectively. (c) Lateral cross-section of DI-PBS-1.0 reconstructed from confocal microscopy images (λex = 405 nm) showing fluorescence throughout the sample depth investigated, 68 μm. (d) Lateral cross-section of SP-PBS-0.7 reconstructed from confocal microscopy images (λex = 405 nm) showing fluorescence from a 12–14 μm surface layer. Sample depth investigated, 32 μm. (e) Photograph of DI-PBS-0.0, DI-PBS-1.0, DI-PBS-2.0 and DI-PBS-4.0 under UV-illumination (λex = 366 nm).
