Jessica Orr

Publications of Jessica Orr

• The tissue diagnostic instrument.

  Authors: Paul Hansma, Hongmei Yu, David Schultz, Azucena Rodriguez, Eugene A Yurtsev, Jessica Orr, Simon Tang, Jon Miller, Joseph Wallace, Frank Zok [......] Carol Chen, Mathilde Peters, David Kohn, Jenni Buckley, Xiaojuan Li, Lisa Pruitt, Adolfo Diez-Perez, Tamara Alliston, Valerie Weaver, Jeffrey Lotz

  The Review of scientific instruments. 06/2009; 80(5):054303.

  Tissue mechanical properties reflect extracellular matrix composition and organization, and as such, their changes can be a signature of disease. Examples of such diseases include intervertebral diskTissue mechanical properties reflect extracellular matrix composition and organization, and as such, their changes can be a signature of disease. Examples of such diseases include intervertebral disk degeneration, cancer, atherosclerosis, osteoarthritis, osteoporosis, and tooth decay. Here we introduce the tissue diagnostic instrument (TDI), a device designed to probe the mechanical properties of normal and diseased soft and hard tissues not only in the laboratory but also in patients. The TDI can distinguish between the nucleus and the annulus of spinal disks, between young and degenerated cartilage, and between normal and cancerous mammary glands. It can quantify the elastic modulus and hardness of the wet dentin left in a cavity after excavation. It can perform an indentation test of bone tissue, quantifying the indentation depth increase and other mechanical parameters. With local anesthesia and disposable, sterile, probe assemblies, there has been neither pain nor complications in tests on patients. We anticipate that this unique device will facilitate research on many tissue systems in living organisms, including plants, leading to new insights into disease mechanisms and methods for their early detection.

• The tissue diagnostic instrument

  Authors: Paul Hansma, Hongmei Yu, David Schultz, Eugene A. Yurtsev, Jessica Orr, Simon Tang, Jon Miller, Frank Zok, Richard Souza, Alexander Proctor, Xavier Nogues-Solan, M.Jesus Peña, Lisa Pruitt, Adolfo Diez-Perez, Tamara Alliston, Valerie Weaver, Jeff Lotz

  Review of Scientific Instruments. 05/2009;

  Tissue mechanical properties reflect extracellular matrix composition and organization, and as such, their changes can be a signature of disease. Examples of such diseases include intervertebralTissue mechanical properties reflect extracellular matrix composition and organization, and as such, their changes can be a signature of disease. Examples of such diseases include intervertebral disk degeneration, cancer, atherosclerosis, osteoarthritis, osteoporosis, and tooth decay. Here we introduce the tissue diagnostic instrument �TDI�, a device designed to probe the mechanical properties of normal and diseased soft and hard tissues not only in the laboratory but also in patients. The TDI can distinguish between the nucleus and the annulus of spinal disks, between young and degenerated cartilage, and between normal and cancerous mammary glands. It can quantify the elastic modulus and hardness of the wet dentin left in a cavity after excavation. It can perform an indentation test of bone tissue, quantifying the indentation depth increase and other mechanical parameters. With local anesthesia and disposable, sterile, probe assemblies, there has been neither pain nor complications in tests on patients. We anticipate that this unique device will facilitate research on many tissue systems in living organisms, including plants, leading to new insights into disease mechanisms and methods for their early detection. © 2009 American Institute of Physics. �DOI: 10.1063/1.3127602� I. INTRODUCTION The tissue diagnostic instrument �TDI� was redesigned from the bone diagnostic instrument1,2 so as to measure tissue mechanical properties subcutaneously and in vivo with additional probe assemblies and an adjustable compliance �Fig. 1�. It consists of a thin probe assembly that can penetrate skin and soft tissue to reach deep tissues. The disposable, sterilizable probe assembly consists of an outer reference probe made from a 23 gauge hypodermic needle and an inner test probe made from stainless steel wire ranging from 175 to 300 �m in diameter and from 2 to 90 mm in length. Since friction between the test probe and the reference probe increases with length, it is desirable to use only the length needed to access the desired tissue location. The test probe is held in a nickel tube that couples to a magnet, which in turn is linked to a force generator. During operation the force generator oscillates the probe within the tissue of interest and concurrently measures the force and displacement. The maximum values for force and displacement are 12 N and 600 �m. The probe is typically operated at a frequency of 4 Hz because this is rapid enough to allow hand holding yet sufficiently slow to allow easy decoupling of the elastic and viscous response of the tissue �see supplementary material3 for more details including force and displacement ranges.� II. MEASUREMENTS We first illustrate TDI use in human spinal disks that are composed of a thick outer ligament �annulus fibrosus� and a central swelling hydrogel �nucleus pulposus�. Spinal disk degeneration can be the underlying cause of back pain leading to significant morbidity and societal expense. Intervertebral disks are one of the most highly loaded tissues in the body, and consequently material property insufficiency can lead to damage accumulation, inflammation, and pain. Disk degen- REVIEW OF SCIENTIFIC INSTRUMENTS 80, 054303 �2009� 0034-6748/2009/80�5�/054303/6/$25.00 80, 054303-1 © 2009 American Institute of Physics Downloaded 28 May 2009 to 72.215.163.35. Redistribution subject to AIP license or copyright; see http://rsi.aip.org/rsi/copyright.jsp