Facile Batch Fabrication of Hydrogel Atomic Force Microscope Cantilevers via Capillary Filling and Ultraviolet Curing in an Aligned Elastomeric Mold Pair

Abstract

This letter reports the facile batch fabrication of hydrogel (polyethyleneglycol diacrylate; PEGDA) atomic force microscope (AFM) cantilevers via capillary filling and ultraviolet curing in an aligned polydimethylsiloxane (PDMS) mold pair. One mold exhibits the tip and beam structures, and the other mold exhibits the base structure. Once two PDMS molds are aligned, PEGDA prepolymer capillary-driven into the mold pair is solidified by a single UV exposure and 15 PEGDA AFM cantilevers with their tip radii of ~200 nm are fabricated simultaneously. After oxygen plasma treatment sharpens imaging tips down to ~50 nm, reflective metal is selectively deposited onto 15 cantilevers via a laser-machined shadow mask. Finally, each PEGDA AFM cantilever is easily individualized. Fabricated PEGDA AFM cantilevers are thoroughly characterized and used for nanoscale imaging of HeLa cells, calibration gratings, and DVD media.