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3-D Printing

Chemistry In Pictures

Chemistry in Pictures: Tiny Tannenbaum

by Manny I. Fox Morone
December 19, 2023


A cartoonish Christmas tree with blue lights and red ornaments is drawn using colorful dots. Each dot is a microneedle with fluorescent dye mixed inside it printed using an extruder.
Credit: Yanyan Li/ACS Nano
A closeup view of red, green, and blue microneedles show how they point upward from a black surface. Each dot was printed individually, and together they make a Christmas tree design.
Credit: Yanyan Li/ACS Nano

Most Christmas trees are made of fir or pine needles, but this one is made of microneedles. Standing around 50 mm tall, the tree was printed out of tiny dollops of a nanoparticle-polymer composite and fluorescent dyes. Those dollops solidify into microneedles as they dry. A team at Nanjing University headed by Xinghai Ning, Xiaoliang Wang, and Desheng Kong developed these composite inks as part of an straightforward method to fabricate microneedle devices that are catching on as devices for injecting medicines into skin and other tissues such as eyes with less pain. The researchers thought the colors and irregular shape of a Christmas tree demonstrated the flexibility of the printing technique. Unlike other methods for making microneedles such as pre-made molds, this method allows for making on-the-fly shapes, which the researchers say will be useful as microneedles are incorporated into new medical wearables. You can see the printer at work below.

Credit: Yanyan Li/ACS Nano. Read the ACS Nano paper here.

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