Biofabrication Using Electrochemical Devices and Systems

Abstract

Biofabrication is roughly defined as techniques producing complex 2D and 3D tissues and organs from raw materials such as living cells, matrices, biomaterials, and molecules. It is useful for tissue engineering, regenerative medicine, drug screening, and organs‐on‐a‐chip. Biofabrication could be carried out by microfluidic techniques, optical methods, microfabrication, 3D bioprinting, etc. Meanwhile, electrochemical devices and/or systems have also been reported. In this progress report, the recent advances in applying these devices/systems for biofabrication are summarized. After introducing the concept of biofabrication, biofabrication strategies using electrochemical approaches are summarized. Then, various electrochemical systems such as probes and chip devices are described. Next, the biofabrication of hydrogels for 3D cell culture, electrochemical modification on cell culture surfaces, electrodeposition of conductive materials in hydrogels for cell culture, and biofabrication of cell aggregates using dielectrophoresis is discussed. In addition, electrochemical stimulation methods such as electrotaxis are mentioned as promising techniques for biofabrication. Finally, future research directions in this field and the application prospects are highlighted.

Hydrogel Patterning with Catechol Enables Networked Electron Flow

“…We are investigating the use of redox as a modality for bioelectronic communication [ 2,30,31 ] and have previously shown that the coating of electrodes with catechol‐based hydrogel films confers important molecular electronic properties for amplifying, rectifying, and gating redox‐based electrical currents. [ 15,17,32–35 ] Here, we extended a simple electrofabrication method [ 36–42 ] to pattern catechols onto a flexible hydrogel film, and developed a network model to analyze the redox‐based electron flow through this patterned region. We report that: the patterned catechol regions serve as a node for the networked flow of electrons; both the catechol pattern and the redox‐state of the catechol node can be detected (i.e., “read”) optically and electrochemically; and the redox‐state of this node can be switched through biologically based (i.e., enzymatic) activities.…”

Catechol Patterned Film Enables the Enzymatic Detection of Glucose with Cell Phone Imaging

“…As illustrated in Scheme a, we extended a simple electrofabrication method ,− to pattern catechols onto the surface of chitosan/agarose hydrogel film. ,, The films were first prepared by mixing warm agarose and slightly acidic chitosan solutions, casting these solutions into films, and then neutralizing the protonated chitosan chains (Chit-H + ) into their deprotonated state (Chit 0 ). This film was designated Chit 0 /agarose. ,,, The spatially selective patterning of the Chit 0 /agarose film with catechol moieties was performed by immersing the film in a catechol solution (10 mM), placing a standard gold electrode (2 mm diameter) directly above the film surface (we estimate the electrode film distance to be less than 30 μm), and applying an oxidizing voltage (+0.6 V vs Ag/AgCl).…”

Electrofabrication of large volume di- and tripeptide hydrogels via hydroquinone oxidation

“…21,22 Electrochemical gelation techniques can be split into two categories; an indirect electrochemical approach and a direct electrochemical approach. 23 A direct electrochemical approach to fabricating hydrogels commonly employs an applied electric field, which results in gel formation through processes such as electrophoresis, dielectrophoresis (DEP) and electrotaxis. 24,25 The gels are formed far from the electrode surface.…”