Protein addressing on patterned microchip by coupling chitosan electrodeposition and ‘electro-click’ chemistry

Abstract

Many applications in proteomics and lab-on-chip analysis require methods that guide proteins to assemble at surfaces with high spatial and temporal control. Electrical inputs are particularly convenient to control, and there has been considerable effort to discover simple and generic mechanisms that allow electrical inputs to trigger protein assembly on-demand. Here, we report the electroaddressing of a protein to a patterned surface by coupling two generic electroaddressing mechanisms. First, we electrodeposit the stimuli-responsive film-forming aminopolysaccharide chitosan to form a hydrogel matrix at the electrode surface. After deposition, the matrix is chemically functionalized with alkyne groups. Second, we ''electro-click' an azide-tagged protein to the functionalized matrix using electrical signals to trigger conjugation by Huisgen 1,3-dipolar cycloadditions. Specifically, a cathodic potential is applied to the matrix-coated electrode to reduce Cu(II) to Cu(I) which is required for the click reaction. Using fluorescently-labeled bovine serum albumin as our model, we demonstrate that protein conjugation can be controlled spatially and temporally. We anticipate that the coupling of polysaccharide electrodeposition and electro-click chemistry will provide a simple and generic approach to electroaddress proteins within compatible hydrogel matrices.

Chitosan to Connect Biology to Electronics: Fabricating the Bio-Device Interface and Communicating Across This Interface

“…For instance, proteins can be bound to chitosan films through non-specific physical (e.g., electrostatic) interactions. In addition, chemical methods have been utilized to alkynylate an electrodeposited chitosan film to enable a subsequent electrically induced click ("electro-click") reaction to covalently conjugate proteins to the film [157].…”

Electrochemical nanoarchitectonics and layer-by-layer assembly: From basics to future

“…Thus, the first example of protein functionalized bio-polymer platforms using electroclick was recently reported. A chitosan film modified with alkyne groups was successfully electroclicked with azide-tagged Bovine Serum Albumin [352]. …”

“…Recently, microelectrode electroclick patterning was applied to polymer platforms. Both PEDOT-N 3 and alkynecontaining chitosan films were coupled with fluorescent clickable molecules, achieving a minimum resolution of 20 m [331,352]. Simple and generic design of lab-on-a-chip devices is expected.…”

Review of Electrochemically Triggered Macromolecular Film Buildup Processes and Their Biomedical Applications

“…110 catalyzed Huisgen reaction, where Cu(I) was generated at the electrode from reduction of Cu(II). 120 Phenol or catechol moieties have been grafted on electrodeposited chitosan by applying an anodic potential by making use of their properties in oxidative state to react with amino groups of chitosan. [121][122][123] Besides improving the mechanical properties, 124 the presence of catechol moieties amplify the electrochemical signal of redox probes in contact with the chitosan gel ( Figure 7).…”