See this article regarding a torsion balance being used to test inverse square law, and the results were that down to distances of 55 nanometers the inverse square law holds and there is no indication of the existence of dark energy.

I am not surprised by these results. I’ve been of the opinion that Dark Matter, Dark Energy, Inflation, Cosmological Constant, and Dark Energy are all just fudge factors to try to make “the big bang theory” conform to observations. It’s like using a complicated lens to make a square peg look round so you can explain how it must have fit into the round hole.