Poly-HEMA as a Drug Delivery Device for
In Vitro Neural Networks on Micro-Electrode Arrays


(Abstract)Delivery of pharmacological agents in vitro can often be a difficult, time consuming, and costly process. In this paper we describe an economical method for in vitro delivery using a hydrogel of poly hydroxyethyl methacrylate (PHEMA) that can absorb up to 50% of its weight of any water-solubilized pharmacological agent. This agent will then passively diffuse into surrounding media upon application in vitro. An in vitro test of PHEMA as a drug delivery device was conducted using dissociated rat cortical neurons cultured on microelectrode arrays. These microelectrode arrays permit the real-time measurement of neural activity at sixty different sites across a network of neurons. Neural activity was compared during the application of PHEMA saturated with cell culture media and PHEMA saturated with bicuculline, a widely used pharmacological agent with stereotypical effects on neural activity patterns. Application of PHEMA saturated with bicuculline produced a gradual increase in concentration in vitro. When the minimum effective concentration of bicuculline was reached, which was found to be 0.59 micromolar using the diffusion properties of the PHEMA, it produced the rapid almost periodic synchronized bursting characteristically associated with this agent. In contrast application of PHEMA saturated in culture media alone had no effect on neural activity reinforcing its inherent inert properties. Since PHEMA is non-toxic, can be molded into a variety of shapes, quickly manufactured in any laboratory, and is inexpensive to produce, the material represents a promising alternative to drug delivery systems on the market today.

Effect on Interburst Interval after application of a bicuculine (Treatment) and placebo rings to five cultures of rat cortical neurons on MEAs relative to baseline:
Figure 5 IBIfigure


Cadotte, A. J. & DeMarse, T. B. (2005) Poly-HEMA as a Drug Delivery Device for In Vitro Neural Networks on Micro-Electrode Arrays. Journal of Neural Engineering, 2(4), 114-122.