Fabrication of free-standing nanoparticle-fused nanosheets and their hetero-modification using sacrificial film

Sheet-shaped carriers, having obverse and reverse surfaces and thus a large contact area as a targeting site, have several advantages over spherical-shaped carriers, which have an extremely small contact area. Herein is proposed a novel method for the preparation of free-standing nanoparticle-fused nanosheets having uniform micrometer shape, nanometer thickness and heterogenous surfaces, using a water-soluble sacrificial film. This was achieved by combination of four processes: (1) specific adsorption of latex beads at pH 5.0 and a concentration of 1.0 × 1011 mL−1 onto a patterned dodecyltrimethoxysilane self-assembled monolayer (DTS-SAM) region by a conventional dry patterning process, (2) fabrication of the latex bead-sheet via thermal-fusion at 110 °C for 60 s, (3) preparation of the free-standing nanosheet by detachment from the DTS-SAM, and (4) hetero-modification of the resulting nanosheet using a water-soluble poly(acrylic acid) as a sacrificial supporting film. Thus, this sheet-shaped carrier having hetero-surfaces can be regarded as a new material for delivery of drugs, hemostatic reagents and as wound dressings for burn injury, etc.