Streptavidin-hydrogel prepared by sortase A-assisted click chemistry for enzyme immobilization on an electrode

Abstract

A tetrameric streptavidin (SA)-appended LPETG tag was site-specifically linked to azido-containing tri-glycine via sortase A catalysis and the resulting azido-modified SA (SA-N3) was retained in the biotin-binding pocket. SA-N3 was polymerized with dibenzylcyclooctyne-modified branched poly(ethyleneglycol) (DBCO-PEG) using azido-modified branched PEG (N3-PEG) as a spacer via copper-free click chemistry. The resulting SA-based hydrogel exhibited gel-like mechanical properties and could immobilize biotin-modified molecules through biotin-SA affinity. Glucose dehydrogenase (GDH) was immobilized in the SA-based hydrogel, and the hydrogel was then coated on a glassy carbon electrode (GCE) and used for the biocatalytic oxidation of glucose. The designed GCE exhibited better performance and stability compared with GDH chemically adsorbed onto a GCE. In addition, the designed GCE anode and a Pt-carbon cathode were assembled into a glucose/O fuel cell that provided a maximum power density and open circuit voltage of 11.8±0.56µWcm and 0.17V, respectively.

A Versatile Chemo-Enzymatic Conjugation Approach Yields Homogeneous and Highly Potent Antibody-Drug Conjugates

“…Moreover, the heterocyclic triazole linkage generated by SPAAC has been previously shown to be highly stable both in vitro and in vivo [ 19 ]. Recent studies that successfully employed enzyme-mediated ligation and click chemistry to prepare PEGylated capsules [ 20 ] and streptavidin-hydrogel [ 21 ], combined with our results, clearly demonstrate the broad utility of this technology. This chemo-enzymatic approach with flexibility and versatility could be readily adapted to a variety of antibodies and toxins, and correlational research is under investigation.…”

Design of Immobilized Enzyme Biocatalysts: Drawbacks and Opportunities

“…Enzyme entrapment or encapsulation of enzymes is based on the entrapment of the enzyme in a polymer network (gel network), which may be organic polymers, silica sol-gel (the sol-gel method is given by the formation of an inorganic polymer network by gelling reactions at low temperatures) or a membrane device (a hollow fiber or a microcapsule). [95][96][97][98] As shown in the Figures 1 (E) and Figure 1…”

“…119 However, enzymes immobilized in hydrogels tend to pour out of the gel, because the enzyme is basically encapsulated in the small pores of the gel, against this, functional hydrogels utilize functional building blocks, such as proteins. 96,102,120 The encapsulation efficiency and controlled release of the enzymes from the gel matrix can be optimized by the addition of chitosan, modified polymers or proteins. 104,105 Alginate is one of the most compatible polymers for immobilization and microencapsulation due to advantages such as: hydrophilic nature, presence of carboxylic acid groups, natural, mechanical stability and stability under extreme operating conditions.…”

New Developments in Medical Applications of Hybrid Hydrogels Containing Natural Polymers

“…Unfortunately, applications of synthetic hydrogels as biomaterials are limited by their absence of bioactivity. The protein-polymer hybrid networks with complex abilities, including bioactivity, stimuli-responsiveness, catalytic activity, or ability to regulate cell behaviors have been/are created to overcome this limitation, maintaining good mechanical properties of materials [42][43][44][45][46]. The term microgel describes a variety of particles that differ substantially in structure, physico-chemical properties, preparation and application and is interchangeably with terms such as nanogel, microsphere and macrogel depending on the numerous particle types falling within the broad sphere of nano-/microparticle shapes and sizes [47][48][49][50].…”