Lab Chat: How to build a better needle

THE NEEDLE HITS A SWEET SPOT BETWEEN TWO LAYERS OF TISSUE. (RANDAL MCKENZIE)

Scientists have given the needle a 21st-century upgrade to make it easier to deliver drugs to the right spot. Here’s what Jeff Karp of Brigham and Women’s Hospital told me about the proof-of-concept work, published in Nature Biomedical Engineering.  

What problem did you set out to solve?  

When you’re inserting a needle into tissue, you can’t see where that needle is going. We set out to design a system that’s as simple as what exists right now, but that could enable better tissue targeting.  

How does your new design work?

When inserting a needle, there's often a thicker tissue encountered before you get to the target. If you're trying to get a needle into a blood vessel, the blood vessel wall is dense, but where you're trying to go is fluid-filled. We designed the needle so fluid can’t come out until you’re no longer in dense tissue. We tested this in a region of the eye with two thin layers of tissue that touch, like a balloon inside of a balloon. We showed that our needle could stop in between without overshooting.