Mechanical Properties of Healthy and ex vivo Onychomycosis Nails and the Influence of a Porphyrin-propylene Glycol Antifungal Formulation

textabstractAims: To investigate nail penetration enhancing effectiveness of a novel drug formulation and ingredients, 40% propylene glycol (PG) and 40 μM multifunctional photosensitizer (MFPS). Proposed formulation was proven effective in photodynamic treatment (PDT) of ex vivo fungal infections of human nails (onychomycoses) and indirectly also to weaken nail’s strength. Study Design: To directly proof the effect of the novel formulation on nail’s hardness Atomic Force Microscopy (AFM) was employed to measure small-distance forces. Based on indentations Young’s moduli of healthy and ex vivo onychomycosis nails were calculated before and after treatment with the novel formulation. Changes in young’s modulus can be related to changes in nail’s strength and thus formulation effectiveness. Additionally, AFM imaging was employed to study topographical / roughness changes resulting from the treatments to both nail types. Trichophyton mentagrophytes, representative for clinical onychomycosis, was chosen to induce nail infections.