Patent ID: 7741107

Claim:
A biological indicator for monitoring sterility, comprising: a substrate; a surface layer containing functional groups residing on said substrate, said surface layer functional groups containing about 10% or less of any silicon linking atoms based upon the total amount of said surface layer functional groups; a plurality of microorganism indicators, said microorganisms comprising an endospore, a fungi, a mycobacteria, a vegetative bacteria, or a protozoa, or any combination thereof; and a heterobifunctional crosslinking agent having one functional end group covalently bonded to one of said surface layer functional groups and having another functional end group covalently bonded to one of said microorganism indicators so that a terminal and exposed microorganism indicator is present that is covalently bonded through said crosslinking agent to said surface layer, said surface layer having a plurality of said terminal and exposed microorganisms bound thereto that are capable of being sterilized by a sterilizing medium; wherein said heterobifunctional crosslinking agent is terminated on one end by a maleimide and on the other end by an N-hydroxysuccinimide ester and is reactive to both an amine and a sulfhydryl group; and wherein said plurality of said exposed and bound microorganism indicators covalently bonded to said surface layer through said crosslinking agent have a uniform distribution wherein the standard deviation thereof is about 50% or less based on one unit area of said surface layer as compared to another unit area of said surface layer.