The IDEAS laboratory is collaborating with the Center for Implantable Devices at Purdue and the Jackson Laboratory to develop an ultra-miniature intraocular pressure (IOP) sensor to be implanted inside a mouse eye for glaucoma study. Glaucoma is a fatal disease that causes blindness in millions of people worldwide. Mice provide an useful experimental system to collect long term data for genetic diseases because of the similarities between mouse and human physiology. In order to study the exact mechanism of the disease, continuous monitoring of IOP using an implanted sensor is necessary. However, the size, round surface of the anterior chamber of the mouse eye, and the maximum allowable incision size (< 1 mm) do not allow current IOP sensors on rigid substrates to be used as a mouse eye implant (Fig. 1).

Fig. 1. Ultrasonic image of a mouse eye (S. W. M. John et al., Investigative Ophthalmology, 1998)

it can recover its shape after being squeezed during implantation. Components of the IOP sensor are integrated on a thin and flexible polymer interposer such as liquid crystal polymer (LCP) or Parylene. In initial work, we have demonstrated enabling technologies to achieve the IOP sensor [1]-[6]: feasibility of the MEMS capacitive pressure sensor integrated on a polymer substrate, remote sensing using a Nitinol antenna, packaging techniques for the integration of components of the IOP sensor, and in-vivo IOP measurement using a passive third-order harmonic IOP sensor implanted inside a mouse eye as shown in Fig. 3. The ultimate goal is to create a fully integrated active IOP sensor in an ultra-small form factor, based on the initially demonstrated technologies.

Fig. 3. The fully packaged Parylene tag (left) and its implantation inside the mouse eye (right)

Currently Involved Students

Recent Publications

[1] D. Ha, T. Lin, W. N. de Vries, B. Kim, A. L. Chlebowski , S. W. M. John, P. P. Irazoqui, and W. J. Chappell, “A Compact-Size Packaged Third-Order Harmonic Tag for Intraocular Pressure (IOP) Monitoring inside a Mouse Eye,” IEEE MTT-S Int. Microwave Symp. Digest, Montreal, Canada, June 2012. (Accepted)

[2] D. Ha, W. N. de Vries, S. W. M. John, P. P. Irazoqui, and W. J. Chappell, “Polymer-based Miniature Flexible Capacitive Pressure Sensor for Intraocular (IOP) Monitoring inside a Mouse Eye,” Biomedical microdevices, vol. 14, no. 1, pp. 207-215, Feb. 2012.

[3] T. Lin, D. Ha, W. N. de Vries, B. Kim, A. L. Chlebowski , S. W. M. John, P. P. Irazoqui, and W. J. Chappell, “Ultra-thin Tag Fabrication and Sensing Technique using Third Harmonic for Implantable Wireless Sensors,” IEEE MTT-S Int. Microwave Symp. Digest, Baltimore, MD, June 2011.

[4] D. Ha, T. Lin, B. Kim, S. W. M. John, P. P. Irazoqui, and W. J. Chappell, "Small form factor (SFF) Packaging on Liquid Crystal Polymer (LCP) for Implantable Wireless Intraocular Pressure (IOP) Sensor inside Mice Eye" URSI National Radio Science Meeting, Boulder, CO, Jan. 2011.

[5] D. Ha, T. Lin, B. Kim, P. P. Irazoqui, and W. J. Chappell, "Advanced 3D Packaging of Miniature Biomedical Sensor,” International Symposium on Microelectronics, International Microelectronics and Packaging Society (IMAPS), Raleigh, USA, Nov. 2010.

[6] E. Y. Chow, D. Ha, T. Lin, W. N. de Vries, S. W. M. John, W. J. Chappell, and P. P. Irazoqui, “Sub-cubic Millimeter Intraocular Pressure Monitoring Implant to Enable Genetic Studies on Pressure-Induced Neurodegeneration,” Conf Proc IEEE Eng Med Biol Soc, Sep. 2010.

[7] D. Ha, B. Kim, T. Lin, Y. Ouyang, P. P. Irazoqui, and W. J. Chappell, "3D Packaging Technique on Liquid Crystal Polymer (LCP) for Miniature Wireless Biomedical Sensor," IEEE MTT-S Int. Microwave Symp. Digest, May 2010.