Real-Time Analysis of Porphyrin J-Aggregation on a Plant-Esterase-Functionalized Surface Using Quartz Crystal Microbalance with Dissipation Monitoring

摘要

The J-aggregation of meso-tetra (4-sulfonatophenyl) porphine (TPPS_4) on a plant-esterase-functionalized surface in a 1:1 v/v mixture of 0.05 M HCl/ethanol (pH ~1.38) was analyzed in real time using a quartz crystal microbalance with dissipation monitoring (QCM-D). Simultaneous changes in frequency (Δf) and energy dissipation (ΔD) correlated well with mass and structural changes during the sequential phases of slow nucleation, rapid aggregation, and equilibration in J-aggregation. The time-dependent mass adsorption could be quantitatively analyzed with a model, which integrated two simple equations obtained when the surface concentration of TPPS_4 (Γ_(TPPS4)) was below and above the critical aggregation surface concentration (CASC). This study provides a new view for the proteininduced J-aggregation process, which may be helpful for understanding the interactions of self-assembled nanostructures with biomolecules.