Normally, filtering onto alumina anodiscs works well, but for applications where the graphene membrane is required to be flexible such as in a fuel cell, the notoriously brittle anodiscs are a no-go.
As much as 30% of human genes code for membrane proteins. But of more than 65,000 structures in the RCSB Protein Data Bank, fewer than a dozen full-size human membrane proteins are represented.