Enzyme Nanoreactor for In Vivo Detoxification of Organophosphates

Abstract

A nanoreactor containing an evolved mutant of Saccharolobus solfataricus phosphotriesterase (L72C/Y97F/Y99F/W263V/I280T) as a catalytic bioscavenger was made for detoxification of organophosphates. This nanoreactor intended for treatment of organophosphate poisoning was studied against paraoxon (POX). Nanoreactors were low polydispersity polymersomes containing a high concentration of enzyme (20 μM). The polyethylene glycol−polypropylene sulfide membrane allowed for penetration of POX and exit of hydrolysis products. In vitro simulations under second order conditions showed that 1 μM enzyme inactivates 5 μM POX in less than 10 s. LD 50 -shift experiments of POX-challenged mice through intraperitoneal (i.p.) and subcutaneous (s.c.) injections showed that intravenous administration of nanoreactors (1.6 nmol enzyme) protected against 7 × LD 50 i.p. in prophylaxis and 3.3 × LD 50 i.p. in post-exposure treatment. For mice s.c.-challenged, LD 50 shifts were more pronounced: 16.6 × LD 50 in prophylaxis and 9.8 × LD 50 in post-exposure treatment. Rotarod tests showed that transitory impaired neuromuscular functions of challenged mice were restored the day of experiments. No deterioration was observed in the following days and weeks. The high therapeutic index provided by prophylactic administration of enzyme nanoreactors suggests that no other drugs are needed for protection against acute POX toxicity. For post-exposure treatment, co-administration of classical drugs would certainly have beneficial effects against transient incapacitation.

Biomedical Nanosystems for <i>in vivo</i> Detoxification: From Passive Delivery Systems to Functional Nanodevices and Nanorobots

“…In our laboratory, we focus on the design and development of injectable therapeutic enzyme nanoreactors for the neutralization of toxicants like organophosphorous (OP) pesticides [ 87 ]. Enzymes capable of detoxifying OPs can be used as bioscavengers.…”

“…Удаление этанола дополнительно ускорялось добавлением H 2 O 2 , который быстро разлагался до O 2 с помощью каталазы. В модели интоксикации грызунов этанолом ферментные липосомы усиливали метаболизм этанола, о чем свидетельствовала повышенная продукция основного метаболита этанола -ацетальдегида[84].Работы нашей группы сосредоточены, в частности, на проектировании и разработке инъекционных терапевтических ферментных нанореакторов для нейтрализации таких токсинов, как фосфорорганические соединения (ФОС)[87]. Известно, что ферменты, способные нейтрализовать ФОС, могут быть использованы в качестве стехиометрических, псевдокаталитических или каталитических «биоловушек»[88,89].…”

Controlled Release and Capture of Aldehydes by Dynamic Imine Chemistry in Nanoemulsions: From Delivery to Detoxification

“…21 A polymersome nanoreactor loaded with enzymes was used for in vivo detoxification of organophosphates. 22 To capture specifically a peptide toxin, NPs based on molecularly imprinted polymers were also proposed, capable of neutralizing the toxin even in a complex biological milieu. 23 In an alternative strategy, biodegradable polymer poly(lactic-co-glycolic acid) (PLGA) NPs coated with red blood cell membranes were proposed as "nanosponges" that absorb pore-forming toxins in vivo.…”

“…Thus, nanoparticles (NPs) functionalized with enzymes with complementary functions, alcohol oxidase and catalase, could reduce blood alcohol levels in intoxicated mice . A polymersome nanoreactor loaded with enzymes was used for in vivo detoxification of organophosphates . To capture specifically a peptide toxin, NPs based on molecularly imprinted polymers were also proposed, capable of neutralizing the toxin even in a complex biological milieu .…”

Dual-Modal Nanoscavenger for Detoxification of Organophosphorus Compounds

“…Enzyme immobilization is an effective method to improve the stability of bioscavengers. Specifically, multiple strategies, such as adsorption, covalent bonding, encapsulation, and copolymerization, can be used to physically attach enzymes to a solid support (carrier) to isolate enzymes from aggressive environments. − Mesoporous metal–organic frameworks (MOFs) have emerged as advanced materials for enzyme immobilization due to their tunable size, high surface area, and possible biofunctionalization. − These special properties endow MOFs with high enzyme loading, stable catalytic activity, and excellent diffusion of both substrate and product . Zeolitic imidazole framework-8 (ZIF-8), formed by coordination between 2-methylimidazole and Zn 2+ ions, is a typical and excellent MOF material for one-pot enzyme encapsulation with mild synthesis conditions and good biocompatibility and stability. , However, clearance by the immune system is still one of the major issues of enzyme/MOF nanoparticles, which may lead to attenuation of enzyme activity, necessitating further functionalization of these nanoparticles. , …”