I would like to use BTC to invest into a particular thing (Medical stock)... is there such a website that will allow me to do so?
I would like to suggest you to not to go in stock market directly with reference of another third party .
Because that are not safe ( you can check history at google that how they cheated people and how they stopped their services ) .
So better to have your own Demet account from Bank and do investment manually in any type of stock category that you want .
Here I myself is in stock market , that's why I recommended to you to go manually for it .