The Gilbert Biomaterials and Regenerative Medicine Laboratory

RESEARCH: CELL SURFACE INTERACTIONS

Role of electrochemistry on cell viability and phenotype

Cells cultured on electrochemically controlled metallic surfaces respond to the electrochemical state of the alloy surface. The Gilbert Lab has defined an “Electrochemical Zone of Viability” defined by the electrochemical potential range where cells cultured on the surface of an alloy will remain viability after 24 h. This work has discovered, for example, that reducing conditions (where the electrode potential is less than -400 mV (vs Ag/AgCl) will rapidly induce apoptosis regardless of alloy. In addition, rapid cell death on CoCrMo surfaces can be induced (necrosis) when its electrode potential is above about 400 mV (vs Ag/AgCl).


Haeri M, Wollert T, Langford GM, Gilbert JL, “Electrochemical Control of Cell Death by Reduction-Induced Intrinsic Apoptosis and Oxidation-Induced Necrosis on CoCrMo Alloy In-vitro”, Biomaterials, 33 (2012), 6295-6304.


The current hypothesis is that reduction reactions generate reactive oxygen intermediates similar in nature to those reactive oxygen species generated biologically by the immune and inflammatory cells of the body, and these reactive intermediates are similarly lethal to any biological cell in close proximity. This includes bacterial biofilms on the surface and any cancer cells that may be present. Alternative methods rely on galvanically coupled bimetallic systems (e.g., Mg/Ti) to induce the reactive reduction intermediates (Kim and Gilbert, Acta Bio, 2016).


Haeri et al., Biomaterials 2012

Electrochemical Zone of Viability for CoCrMo alloy surfaces

Ehrensberger and Gilbert, J Biomed Mat Res – Part A, 2010

Electrochemical Zone of Viability for Titanium. 

This work has opened up a number of important research areas that relate to infection and cancer therapies and has resulted in several patents.

References for the role of electrode potential on cell behavior:
Gilbert JL, Zarka L, Chang E, Thomas C, “The Reduction Half-Cell in Biomaterials Corrosion: Oxygen Concentration Profiles Near and Cell Response to Polarized Titanium”, J Biomed Mater Res, 1998: 42; 321-330.

Ehrensberger M, Sivan S, Gilbert JL, “Titanium is NOT “The Most Biocompatible Metal” Under Cathodic Potentials: The Relationship Between Voltage and MC3T3 Pre-Osteoblast Behavior on Electrically Polarized cpTi Surfaces”, J Biomed Mat Res Part (A), 2010, June: 93A(4); 1500-1509.

Haeri M, Wollert T, Langford GM, Gilbert JL, “Electrochemical Control of Cell Death by Reduction-Induced Intrinsic Apoptosis and Oxidation-Induced Necrosis on CoCrMo Alloy In-vitro”, Biomaterials, 33 (2012), 6295-6304.

Sivan S, Kaul S, Gilbert JL, “The Effect of Cathodic Electrochemical Potential on Cell Viability: Voltage Threshold and Time Dependence”, J Biomed Mat Res, Part B, May, 2013, Vol 101, No 8: 1489-1497.

Haeri M, Gilbert JL, “Voltage-Controlled Cellular Behavior on Polarized cpTi with Varying Surface Oxide Thickness”, Bioelectrochemistry, (2013); 94:53–60.

Haeri M, Gilbert JL, “Study of Cellular Dynamics on Polarized CoCrMo Alloy Using Time-Lapse Live-Cell Imaging”, Acta Biomaterialia, April 2013, 9(11): 9220-9228.
Metallic surface-cell interactions where electrochemical effects are investigated or exploited include:

Anti-infection therapeutic approaches using reduction electrochemistry

References:
Guo, MS Thesis, 2011: E Coli cultured on Ti discs for 24 h (OCP: Right, -1.0 V: Left). Note perforated membranes for -1V treatment. (Guo J, “Interactions of bacterial biofilms with electrochemically active titanium surfaces undergoing reduction”, MS Thesis, Syracuse University, 2013)

Szkotak R, Niepa THP, Jawrani N, Gilbert JL, Jones MB, Ren D “Differential Gene Expression to Investigate the Effects of Low-level Electrochemical Currents on Bacillus Subtilis”, AMB Express, 2011, 1:39.

Niepa THR, Gilbert JL, Ren D, “Controlling Pseudomonas Aeruginosa Persistent Biomaterials Infections by Weak Electrochemical Currents and Synergistic Effects with Tobramycin”, Biomaterials, 33 (2012), 7356-7265.

Niepa THR, Snepenger LM, Wang H, Sivan S, Gilbert JL, Jones MB, Ren D, “Sensitizing Pseudomonas Aeruginosa to Anitbiotics by Electrochemical Disruption of Membrane Functions”, Biomaterials, Vol. 74, Jan 2016, pp 267-279.

Kim J, Gilbert JL. Cytotoxic effect of galvanically coupled magnesium–titanium particles. Acta Biomaterialia. 2016 Jan 15; 30: 368-77.
Anti-cancer electrochemical therapeutic approaches Anti-cancer and antibacterial approaches using electrochemical processes includes using externally applied potentials to drive electrode reactions. Kim J, Gilbert JL, “In-Vitro Cytotoxicity of Galvanically Coupled Magnesium-Titanium Particles on Human Osteosarcoma SAOS2 Cells: A Potential Cancer Therapy”, submitted, J Biomed Mat Res – Part B, in review, 2017.

Inflammatory cell-metal interactions

This work has also raised the hypothesis that ROS species generated biologically in inflammatory or immune reactions can alter the corrosion properties of metallic biomaterials. Studies have focused on the electrochemical changes that arise from exposure to ROS species. Both increase oxidizing power of the solution and degradation of the oxide film passive properties result from these chemical species. To date, the role of hydrogen peroxide, Fenton reaction chemistry and hypochlorous acid effects are being studied.


(From Liu and Gilbert, J Biomed Mat Res – Part B: App Biomat, 2017) Effect of simulated inflammatory conditions of the open circuit potential (OCP) of CoCrMo in Phosphate Buffered Saline (PBS)
.

Impedance Spectroscopy results (Bode Diagrams) for CoCrMo in varying concentrations of H2O2 in PBS (Liu and Gilbert, JBMR-B, 2017)


References:
Gilbert JL, Sivan S, Liu Y, Kocagoz S, Arnholt C, Kurt SM, “Direct In Vivo Inflammatory Cell Induced Corrosion of CoCrMo Implant Surfaces”, J Biomed Mat Res A, (2015); 103(1): 211-223.

Liu Y, Gilbert JL, “The Effect of Simulated Inflammatory Solutions and Fenton Chemistry on the Electrochemistry of CoCrMo Alloy”, J Biomed Mat Res Part B: Appl Biomat, 10.1002/jbm.b.33830, Jan 24, 2017.

Liu Y, Gilbert JL, “The effect of simulated inflammatory conditions and pH on fretting corrosion of CoCrMo alloy surfaces”, Wear, Vol. 390–391, 15 November 2017, pp 302-311.

Gilbert JL, “Corrosion in the Human Body: Metallic Implants in the Complex Body Environment” Corrosion, August 2017, doi.org/10.5006/2563.

Gilbert JL, Mali S, “Medical Implant Corrosion: Electrochemistry at Metallic Biomaterial Surfaces”, Degradation of Implant Materials, Ed. N. Eliaz, Springer Press, 2012.

Gilbert JL, Kubacki GW, “Oxidative Stress, Inflammation and the Corrosion of Metallic Biomaterials: Corrosion Causes Biology and Biology Causes Corrosion”, Oxidative Stress and Biomaterials, Ed. TD Dziubla, DA Butterfield, Elsevier Press, 2015, Chapt. 3.