In vivo and in situ imaging of controlled-release dissolving silk microneedles into the skin by optical coherence tomography.

Nowadays, transdermal drug delivery has become a hot topic with regard to delivery. Also, the percutaneous microneedle patch made of water-soluble material makes this technique one step closer to clinical application. The process of the microneedle patch penetrates and dissolves in the animal skin can directly reflect the efficiency of drug delivery. Hence, it is important to reflect the situation of microneedles dissolution and drug release by in vivo and in situ imaging in real time. This paper's purpose is to use the means of OCT (optical coherence tomography) to realize assessment of dissolving microneedles delivery efficiency in vivo and in situ imaging. This is the first study to utilize OCT to observe the dissolving process of silk microneedles (SFM) in different carriers. Dissolving process es of silk fibroin microneedles in different carriers were captured by the OCT system. The solution rate of silk fibroin microneedles in water is rapid. It also has good solution in the skin of mouse in vivo. OCT is a noncontact, noninvasive imaging technique with high resolution, the detecting depth of which is generally 1-3 mm under the skin. OCT has great potential to observe the solution process of dissolving microneedles in the skin.