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Force-measuring Silicon Microprobe

詳細技術說明

A team from Cornell has created, and is developing, a self-advancing microprobe that can measure the stiffness of material it penetrates, for use in reproductive medicine and diagnostics.

*Abstract

A team from Cornell has created, and is developing, a self-advancing microprobe that can measure the stiffness of material it penetrates. The device incorporates an ultrasonic actuator (PZT) attached to a catenoid shaped horn to facilitate the initial penetration into the material, preventing damage to the delicate tips and minimizing damage to the target material. The silicon microprobe tips, projecting outwards at the tip of the horn, are 100m wide and have blade-like edges (see figure above). Four polyresistors per microprobe tip measure the compressive/tensile strain experienced by the microprobes as they advance.

This device has been tested in the context of reproductive medicine: namely, in a procedure called testicular sperm extraction ("TESE") that is used for sperm retrieval from men with non-obstructive azoospermia. Under the current practice, the surgeon removes semiferous tubules from the testicles, and does not know until afterwards whether the tubules contain active sperm. Since it is known that tubules with low spermatogenesis have thinner walls and smaller diameter, as compared to healthy tubules, this device can be useful to choose tubules to remove. By monitoring the force experienced by this probe, inserted with a 100 micron scale incision, the surgeon can map the diameter and stiffness of tubule walls encountered during the incision and thus can distinguish between tubules carrying fertile and infertile sperm. The probe can incorporate a channel, through which sperm can be suctioned during examination, allowing the surgeon to leave the tubule in place.

 

Advantages:

The device could eliminate the need for a large incision, excision of large volumes of testicular tissue, and would speed and alleviate recovery and reduce risks of permanent damage to the testis.

 

Potential Applications:

• Reproductive medicine, e.g. sperm extraction
• Medical diagnostics, e.g. diagnosis of cancers such as prostate and liver, in which the fibrous and stiff nature of the cancer tissue distinguishes it from surrounding tissue.
• A probe based on our design could be usefully incorporated into robotic surgical arms in order to provide feedback for closed-loop control systems.

*Licensing

Patrick Govangpjg26@cornell.edu(607) 254-2330

其他

• Patent:  US 8197418
• Ramkumar A. et al, "Micro-Dissecting Dual-Probe Testicular Tubule Assay", Solid-State Sensors, Actuators and Microsystems Conference (TRANSDUCERS 2007), pp 1959-1962
• Ramkumar A. et al, "Ultrasonic Microprobe Based Tubular Size Assay", IEEE International Ultrasonic Symposium, 28th-31st October, 2007 (in print)

 

Background on the testicular sperm extraction procedure:

P. N. Schlegel (1999) Testicular sperm extraction: microdissection improves sperm yield with minimal tissue excision. Human Reproduction 14(1) 131-135.

 

Related publications and patents by Lal and Ramkumar:

• Chen, X, et al (2006) Ultrasonically Actuated Silicon Microprobes for Cardiac Signal Recording. IEEE Transactions on Biomedical Engineering 53(8) 1665-71
• Son, I., Lal, A. (2002) Remotely Actuated Magnetic Actuator For Microsurgery With Piezoresistive Feedback. Proceedings of the 2nd Annual International IEEE-EMBS Special Topic Conference on Microtechnologies in Medicine & Biology, Madison, WI.
• Chen, X, Lal, A. (2001) Integrated Pressure and Flow Sensor in Silicon-based Ultrasonic Surgical Actuator," IEEE Ultrasonics, Ferroelectrics, and Frequency Control Society Symposium, Atlanta.
• Chen, X., Lal, A., (2001) Micromachined Ultrasonic Ophthalmic Microsurgical tool with integrated Pressure sensor. Digest of Technical publications, International Conference on Solid State Sensors and Actuators, Munich.
• Son, I. et al (2001) A multifunctional silicon-based microscale surgical system. Sensors and Actuators A. 91(3) 351-356.
• Son, I., Lal, A. (2000) Thin-film Composites for Microsurgery. World Conference on Medical Physics and Biomedical Engineering, Chicago.
• Lal, A., White, R. M. (1996) Silicon micro-fabricated horns for power ultrasonics. Sensors and Actuators, vol. A54, pp. 542-546.
• Amit Lal. (1996) "Micromachined Silicon Ultrasonic Longitudinal Mode Actuators: Theory and Applications to Surgery, Pumping, and Atomization," Ph.D. Dissertation, University of California, Berkeley. pp. 1-175.

國家/地區

美國