Butyrylcholinesterase nanocapsule as a long circulating bioscavenger with reduced immune response

Butyrylcholinesterase (BChE) is the most promising bioscavenger candidate to treat or prevent organophosphate (OP) poisoning. However, the clinical application of BChE is limited by two obstacles: an inadequate circulation half-life and limited sources for production. Although several modification technologies including glycosylation and PEGylation have been developed to improve its pharmacokinetics, none of them have been able to outperform blood-derived native BChE. In this work, we designed a long-circulating bioscavenger nanogel by coating equine serum-derived BChE with a zwitterionic polymer gel layer. This zwitterionic gel coating protected BChE from denaturation and degradation under harsh conditions. Notably, the nanocapsule exhibited a long circulation half-life of ~45h, a three-fold increase from the unmodified native version, enabling both therapeutic and prophylactic applications. In addition, the gel coating reduced the immunogenicity of equine BChE, unlocking the possibility to use non-human derived BChE as an OP bioscavenger in humans.