Systems and methods are provided for the removal of endotoxins from fluids. The methods can include the use of polymeric nanoparticles for binding endotoxins present in a fluid. The polymeric nanoparticles can be associated with a support member. The polymeric nanoparticles can have an endotoxin removal capacity of at least 1×109 endotoxin units per gram of polymeric nanoparticle (EU/g) and/or a removal efficacy per unit surface area of the polymeric nanoparticles of at least 1×106 EU/cm2.