The three-dimensional distribution of the nanoparticles in the gel matrix was carried out using silica nanoparticles (SiNP) and the previously mentioned EVs. Nanoparticle suspensions were added to the gel precursor solution and mixed thoroughly to homogenize the mixture. The gels were kept under humid conditions to avoid drying and release of the nanoparticles. The samples were investigated after 2 days by using the previously mentioned ZEISS microscope.