If you have access to a lab you can make your own. This video[0] has basic ingredients and instructions. This paper[1] explains some variations on the ink formu

If you have access to a lab you can make your own. This video[0] has basic ingredients and instructions. This paper[1] explains some variations on the ink formulation. [0]: http://www.youtube.com/watch?v=dfNByi-rrO4 http://www.youtube.com/watch?v=dfNByi-rrO4 [1]: http://staff.ustc.edu.cn/~yjxiong/paper/Science-2.pdf http://staff.ustc.edu.cn/~yjxiong/paper/Science-2.pdf