QCM - Multilayer assembly. Multilayer formation of a 4-bilayer assembly of cyt c/SiNP Ø = 5 nm). The adsorption behavior of SiNPs (Ø = 5 nm) to cytochrome c and vice versa is shown for a 4-bilayer architecture. QCM chips modified with self-assembled monolayer of MUA/MU are successively flushed with solutions of SiNPs (0.5 mg/mL) and cyt c (20 μM), flow rate 25 μL/min. Inset: QCM - Frequency change during the formation of 4-bilayer (cyt c/SiNPs) assemblies on a QCM chip by the use of different sized SiNPs (5, 8, 10, 15, 20 nm).