How to achieve this effect? Does it need a custom shader? I would love to replicate this effect in Blender, but have no idea how to approach the problem. Does it need a custom shader? and if yes, can you link me to references/guides on how to achieve a similar effect?
Its a open source fork of Blender called Bioblender, which can generate 3D models from protein database files.  As far as I can tell, the program uses the Blender Internal renderer to generate images.