> ... and at distances longer than [100 microns], it really follows the ISL
But at cosmic distances, there's also evidence that gravity doesn't follow ISL, right?
Are there any implications of this work for hypothesized dark matter and dark energy?
Gravity not following the ISL at large scales would indeed be a possible explanation for this. However, most alternative theories of gravity clash with other observations, such as the motion of binary pulsars or gravitational waves, whereas (unmodified) General Relativity is in excellent agreement. This is one of the reasons why the existence of dark matter is considered to be a much better explanation for the deviation of the rotation curves.
But I know so little physics that the distinction between dark matter and extra terms in gravitation is unclear.