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A controlled-release microchip

Nature volume 397, pages 335–338 (1999)Cite this article

Abstract

Much previous work in methods of achieving complex drug-release patterns has focused on pulsatile release from polymeric materials in response to specific stimuli1, such as electric2,3,4,5 or magnetic6,7 fields, exposure to ultrasound7,8, light9 or enzymes10, and changes in pH11 or temperature12,13,14. An alternative method for achieving pulsatile release involves using microfabrication technology to develop active devices that incorporate micrometre-scale pumps, valves and flow channels to deliver liquid solutions15,16. Here we report a solid-state silicon microchip that can provide controlled release of single or multiple chemical substances on demand. The release mechanism is based on the electrochemical dissolution of thin anode membranes covering microreservoirs filled with chemicals in solid, liquid or gel form. We have conducted proof-of-principle release studies with a prototype microchip using gold and saline solution as a model electrode material and release medium, and we have demonstrated controlled, pulsatile release of chemical substances with this device.

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Figure 1: A prototype microchip for controlled release showing the shape of a single reservoir.
Figure 2: Removal of an anode membrane to initiate release from a reservoir.
Figure 3: Pulsatile release of a single substance from a microchip device.
Figure 4: Pulsatile release of multiple substances from a single microchip device.

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Acknowledgements

We thank A. Göpferich and M. Llabres for help in the early stages of the project, and K. Jensen, C. Thompson and R. Latanision for discussions about materials and electrochemical aspects of this project. All fabrication work was carried out at the Microsystems Technology Laboratory at MIT. This work was partially supported by the US NSF.

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Authors and Affiliations

  1. Department of Chemical Engineering, and Engineering, Massachusetts Institute of Technology, Cambridge, 02139, Massachusetts, USA

    John T. Santini Jr & Robert Langer

  2. Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, 02139, Massachusetts, USA

    Michael J. Cima

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  1. John T. Santini Jr
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  2. Michael J. Cima
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  3. Robert Langer
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Correspondence to Robert Langer.

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Santini, J., Cima, M. & Langer, R. A controlled-release microchip. Nature 397, 335–338 (1999). https://doi.org/10.1038/16898

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