Regulated Polyelectrolyte Nanogels for Enzyme Encapsulation and Activation

Abstract

Polyelectrolyte (PE) nanogels consisting of crosslinked PE networks integrate the advanced features of both nanogels and PEs. The soft environment and abundant intrinsic charges are of special interest for enzyme immobilization. However, the crucial factors that regulate enzyme encapsulation and activation remain obscure to date. Herein, we synthesized cationic poly (dimethyl aminoethyl methacrylate), PDMAEMA, nanogels with well-defined size and cross-link degrees and fully investigated the effects of different control factors on lipase immobilization. We demonstrate that the cationic PDMAEMA nanogels indeed enable efficient and safe loading of anionic lipase without disturbing their structures. Strong charge interaction achieved by tuning pH and larger particle size are favorable for lipase loading, while the enhanced enzymatic activity demands nanogels with smaller size and a moderate cross-link degree. As such, PDMAEMA nanogels with a hydrodynamic radius of 35 nm and 30% cross-linker fraction display the optimal catalytic efficiency, which is fourfold of that of free lipase. Moreover, the immobilization endows enhanced enzymatic activity in a broad scope of pH, ionic strength, and temperature, demonstrating effective protection and activation of lipase by the designed nanogels. Our study validates the crucial controls of the size and structure of PE nanogels on enzyme encapsulation and activation, and the revealed findings shall be helpful for designing functional PE nanogels and boosting their applications for enzyme immobilization.

Synthesis of Anionic Nanogels for Selective and Efficient Enzyme Encapsulation

“…11 In other studies, encapsulation of lipase in polyelectrolyte micelles and nanogels led to enhanced activity on hydrolysis of 4-nitrophenyl butyrate due to the triggered active state of the enzyme upon complexation with the PE. 12,13 These findings validate that PE nanogels demonstrate advanced nano-carriers for encapsulation and activation of enzymes and therefore hold great potential in bio-catalytic applications. 14−16 Motivated by their advanced features, a variety of PE nanogel fabrication approaches have been developed.…”

“…As hydrogels, PE nanogels exhibit high water content, tuneable structure and functionality, high stability, and biocompatibility. , As polyelectrolytes, they possess abundant and regulated charges which are of special interest for loading of enzymes. − More notably, the polyelectrolyte complexes create favorable environments in which the structure and function of enzyme can be retained. , For example, Dubey and co-workers constructed core–shell PNIPAm-PEI microgels, and the designed cationic PEI blocks realized an efficient loading of Acetyl CoA synthetase . In other studies, encapsulation of lipase in polyelectrolyte micelles and nanogels led to enhanced activity on hydrolysis of 4-nitrophenyl butyrate due to the triggered active state of the enzyme upon complexation with the PE. , These findings validate that PE nanogels demonstrate advanced nano-carriers for encapsulation and activation of enzymes and therefore hold great potential in bio-catalytic applications. − …”

Rational polyelectrolyte nanoparticles endow preosteoclast-targeted siRNA transfection for anabolic therapy of osteoporosis

“…A nonfunctional siRNA (no function, defined as siNC) was selected as negative control. As for the delivery vehicle, we choose a type of "soft" NP, which features both hydrogel and polyelectrolyte properties (24)(25)(26). It is a core-shell polyelectrolyte NP, with a gel-like particle core consisting of a cross-linked cationic polymer that provides abundant positive charges and acts as a hydrated pocket that can carry and protect the anionic siRNA.…”

Rational Design and Development of Polymeric Nanogels as Protein Carriers

“…Additionally combining DLS measurements with electrophoresis analysis can reinforce the loading optimization, as proved by Cai and co‐workers. [ 81 ] They loaded cationic poly (dimethyl aminoethyl methacrylate) NGs with lipase by titration. Besides increasing scattering intensity, when the enzyme is properly encapsulated in the NGs (and able to diffuse to the pores), the electrophoretic mobility of loaded NGs is not affected.…”