sist was spin-coated on the surface of PEG-modified silicon wafers. After exposure to UV light under a photomask, the wafers were immersed in developing solution and then etched via wet etching. The remaining photoresist was removed using acetone.
Self-Assembly of Protein/Silica Nanoparticles in Microwells: The etched silicon wafer was rinsed three times with deionized water, followed by drying of the wafer with dry air. The wafer was immersed in a freshly prepared 1 mg mL ±1 solution of protein/silica nanoparticles for 6 h at room temperature. Then, the wafer was rinsed carefully in deionized water and sonicated in deionized water for 5 min to remove free nanoparticles.
Atomic Force Microscopy (AFM) and Fluorescence Microscopy Measurements: The tapping mode AFM images were taken using a Digital Instruments Nanoscope IIIa DIMM AFM atomic microscope operating at room temperature with an image resolution of 256 pixels 256 pixels at a scan speed of 0.7±1.2 Hz in air. Light and fluorescence photographs were obtained using an Axiostar plus fluorescent microscope with a color charge-coupled device (CCD) camera and image-acquisition system.