A Thermoplastic Transfer Film Spin-Coated for Near-Field Probe Laser-Capture Microdissection System

Abstract

To improve laser-capture microdissection (LCM) resolution, we designed a near-field probe LCM system that pushed microdissection resolution from 7.5 μm to 400 nm. Here, we report a transfer film for our constructed system, replacing commercial transfer films used in conventional LCM systems. A low-melting-point ethylene vinyl acetate (EVA) copolymer was chosen as the main material. Adequate concentrations of EVA and near-infrared (NIR) absorbing dyes of an appropriate thickness to prepare the transfer film were investigated. The flatness of the film surface and the relationship between different film thicknesses and melt dot sizes were studied using atomic force microscopy and scanning electron microscopy, respectively. The results show that the flatness is approximately 4.3 nm, and the melt dot size is proportional to the transfer film’s thickness. The proper conditions for preparing the film were 17.5% (w/v) of EVA in the toluene solution with 0.001 M of NIR absorbing dyes. Using a 30 μm thick transfer film, 200 nm diameter particles on a 20 nm thick monolayer of gold particles could be captured.