AVS 58th Annual International Symposium and Exhibition
    Biofabrication and Novel Devices Focus Topic Tuesday Sessions
       Session BN+NM-TuM

Paper BN+NM-TuM2
Electrically Controlled Biofabrication with Stimuli-Responsive Polysaccharide and Their Visualization in Microfluidic Devices

Tuesday, November 1, 2011, 8:20 am, Room 105

Session: Biofabrication Applications
Presenter: Yi Cheng, University of Maryland, College Park
Authors: Y. Cheng, University of Maryland, College Park
X.L. Luo, University of Maryland, College Park
J. Betz, University of Maryland, College Park
C.Y. Tsao, University of Maryland, College Park
H.C. Wu, University of Maryland, College Park
G.F. Payne, University of Maryland, College Park
W.E. Bentley, University of Maryland, College Park
G.W. Rubloff, University of Maryland, College Park
Correspondent: Click to Email
Stimuli-responsive polysaccharides, such as chitosan and alginate, are useful biomaterials that can be induced to undergo a reversible sol-gel transition to generate biologically-relevant scaffolds. The recent discovery that their gelation can be triggered by imposing an electrical signal opens many avenues for the creation of biologically functional hybrid structures and their localization onto and within microfabricated devices for biofabrication and biosensing applications. Here we report two different mechanisms for creating polysaccharide hydrogels in microfluidics by electrical signal. The cathodic electrodeposition of the cationic chitosan hydrogel was achieved by electrochemically generated OH- ions at the cathode surface, creating a localized pH gradient at the sol-gel interface. The anodic electrodeposition of calcium alginate hydrogel was achieved by electrical-signal-mediated release of Ca2+ ions as a result of electrochemically generated H+ ions at the anode surface reacting with suspended CaCO3 particles in alginate solution. Localization of the hydrogels in transparent microfluidic devices makes them highly accessible through optical imaging and spectroscopy. The processes of in situ gel formation are simple, scalable, spatially controllable, and electroaddressable. Applications in protein immobilization and cell assembly with electroaddressing capability were further demonstrated. With the advantage of spatiotemporal control of gel formation coupled with microfabrication techniques, a variety of novel and useful structures such as multi-layer, multi-address, and even site-programmable arrays of biological components can also be achieved.