Fig. 1: Design and characterization of the BPCL.

a Schematics of the overall snowflake-inspired BPCL structure (left) and exploded illustration of the device components, essential materials, multilayer structures, and repair mechanism (right). b Optical images of an initial BPCL (top) being stretched and twisted (middle) and being worn on an eyeball (bottom). c A three-dimensional microscope image of the multilayers and enlarged view of piezoelectric electret film with a porous loose structure (a scanning electron microscope image). d The height profile along the purple line in (c) shows the height of multilayers. e Characterization of the hydrophobic PDMS and the hydrophilic pHEMA encapsulation layers. f Oxygen permeability characterization of encapsulation layers, n = 3 independent samples. All data in (f) are presented as means ± SD. g FEA and experimental results of the BPCL under different pressing heights. h Fluorescence images of stained fibroblasts cultured on a regular cell culture dish and the encapsulation layer. i Comparison of normalized cell viability for three days showing excellent biocompatibility of the BPCL, n = 3 independent samples. BPCL blink-driven piezoelectric contact lens, PEG polypropylene electret film generator, PDMS polydimethylsiloxane, ITO indium tin oxide, pHEMA poly 2-hydroxyethyl methacrylate, EF electric field, FEA finite element analysis.