Yes, “Extrude borders” is your friend! 
For other ppl reading this: what is seen here is a visual artifact called “edge bleeding” where the edge pixels of neighbouring pixels in an atlas bleed into the image assigned to your sprite. The solution is to pad the edge of your atlas images with extra row(s) and column(s) of identical pixels. Luckily this can be done automatically by the atlas editor in Defold. Open your atlas and set the Extrude Borders value to 1. http://www.defold.com/faq#20