Soft tissue, you can buy any small grinder glass hand held homogenizers depending upon the size of tissue you want to grind. For bone is different issue. I will suggest to buy morter and pestle (made of stones). Place tissue in that and pour liquid nitrogen in the pot and crush till it become fine powder. There are other bead homogenizer electrically vibrating. You need to expensive stuff in that case.

Thanks a lot for your answer...