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Want a ‘Shrinky Dinks’ approach to nano-sized devices? Try hydrogels

Rather than making devices small to begin with, start big and make them small later

tiny animals from the Chinese zodiac, made in hydrogels of different colors. Top row from left: purple monkey, yellow and purple pig, yellow and purple snake, bluish gray dog, green rabbit. Bottom row from left: green tiger, yellow goat, orange horse, purple rooster, teal rat.

These Chinese zodiac animals etched in hydrogels come in many materials, including gold (goat), titanium dioxide (snake) and luminescent nanoparticles (rabbit). The images on the bottom are each a few dozen micrometers wide. The images at the top started that big and were then shrunk to roughly one-tenth their size.