UMass Amherst Polymer Scientists and Physicists, Inspired by Curly Leaves, Develop New Technique for Shaping Thin Gel Sheets
Researchers at the University of Massachusetts Amherst have developed a new tool for manufacturing three-dimensional shapes easily and cheaply.
Story content courtesy of the University of Massachusetts Amherst, News Office, US
The team at UMass Amherst were inspired by nature's ability to shape a petal, and their tool was built on simple techniques used in photolithography and printing.
Ryan Hayward, Christian Santangelo and colleagues describe their new method of halftone gel lithography for photo-patterning polymer gel sheets in a recent scientific publication. They say the technique, among other applications, may someday help biomedical researchers to direct cells cultured in a laboratory to grow into the correct shape to form a blood vessel or a particular organ.
Many plants create curves, tubes and other shapes by varying growth in adjacent areas. While some leaf or petal cells expand, other nearby cells do not, and this contrast causes buckling into a variety of shapes, including cones or curly edges. Building on this concept, Hayward and colleagues developed a method for exposing ultraviolet-sensitive thin polymer sheets to patterns of light. The amount of light absorbed at each position on the sheet programs the amount that this region will expand when placed in contact with water, thus mimicking nature's ability to direct certain cells to grow while suppressing the growth of others.
Areas of the gel exposed to light become crosslinked, restricting their ability to expand, while nearby unexposed areas will swell like a sponge as they absorb water. As in nature, this patterned growth causes the gel to buckle into the desired shape. Unlike in nature, however, these materials can be repeatedly flattened and re-shaped by drying out and rehydrating the sheet.
To date, the UMass Amherst researchers have made a variety of simple shapes including spheres, saddles and cones, as well as more complex shapes such as minimal surfaces. Creating the latter represents a fundamental challenge that demonstrates basic principles of the method, Hayward says.