During my doctorate, I was breeding millimeter-long transgenic worms, barely visible to the naked eye, by sticking DNA into their gonads. We couldn’t find syringes small enough, so we had to make our own. First, we would heat a glass tube about a tenth of a millimeter thick and break it to make a needle. Then we’d snap off the sealed tip to make sure it was open for injections. The improvised instrument is very finicky to make, but it does its job really well.