Surface Functionalized Colloidal Microparticles for Fast Endocytotic Cell Uptake

Abstract Aim of this study is to enhance fast and effective endocytotic uptake of protamine sulfate and dextran sulfate layer‐by‐layer(LbL) coated silica microparticles by specific functionalization with a cell‐penetrating peptide (CPP) surface layer. CPP are known to act as efficient carriers for a wide range of different substances. By coupling CPP to a given compound, the overall cellular uptake can be increased. Coating and stability of the cell‐penetrating peptide (CPP) layer among different conditions are tested by means of fluorescence markers. Furthermore, the quality of the preparation regarding particle aggregation after peptide coating is explored. After 0.5–2 h cell/particle incubation, the number of cells with peptide‐coated particles in endolysosomes is significantly increased related to particles coated with the positively charged biopolymer protamine sulfate (PRM) on top. Thus, our new designed particles functionalized with CPPs are very useful as fast carriers for active agents addressing the endolysosomal compartment of cells.