Sensing the penetration of nanodiamond along different skin layers according to their optical properties

Main challenge in designing nanoparticles (NPs) as nanocarriers for topical treatment drug is detecting NPs permeation through the skin. NPs are typically too small to be detected by regular noninvasive imaging techniques due to their size and depth. Thus, the research proposes the use of the iterative multi-plane optical properties extraction (IMOPE) technique. The technique is a non-invasive method for estimating optical properties of opaque media based on a phase image reconstruction and analysis, which enables the extraction of the sample’s optical properties. IMOPE technique has the capability to detect the presence of NPs in different skin layers as a change of the optical properties when tailored for the optical properties range of the biological sample and the NPs. In the research, an in vivo study was performed with mice treated with a gel formula of drug carried by NPs. After the mice were sacrificed the penetration analysis was done, first by the IMOPE optical technique and afterwords with chemical methods. The analysis compared results of 4 gel groups: NPs only, full complex of NPs with drug, full complex with additional enzyme and enzyme only. The results showed that the NPs penetrated the epidermis and into the dermis with a lower concentration. The enzyme is suggested to enhance NPs penetration into the skin as supported by the optical findings. Overall, the results demonstrated NPs' decreasing permeation profile across different skin layers and highlighted the enzyme's effect on enhancing NPs' penetrability.