A method for passivating a biomaterial surface includes modifying proteinaceous material disposed at the biomaterial surface. The passivation may be effectuated by exposing the biomaterial surface to therapeutic electrical energy in the presence of blood or plasma.

Processes and apparatuses for producing biologically-active, protein-rich microparticles under ambient conditions are disclosed. A protein solution is atomized and collected in a dehydration solvent that is being mixed. The resulting protein microparticles retain high specific activity without the need for large amounts of stabilizing excipients.

Provided is a clot adhesion preventing agent capable of suppressing adhesion of clot to the inner wall surface of a blood collection container. The clot adhesion preventing agent according to the present invention includes a polyether compound or a silicone oil, and an amino acid.