CIMIT blog

Biomimicry and Regenerative Therapeutics

Biomimicry - Nature as Model, Measure and Mentor

 Jeffrey Karp, PhD, Instructor in Medicine and Health Sciences and Technology, Harvard Medical School, Brigham and Women's Hospital; Director, Laboratory for Advanced Biomaterials and Stem-Cell-Based Therapeutics, BWH, jmkarp@partners.org

Moderator: Frederick J. Schoen, MD, PhD, Professor of Pathology and Health Sciences and Technology, Harvard Medical School; Director of Cardiac Pathology and Executive Vice-Chairman,Department of Pathology, Brigham and Women’s Hospital, CIMIT Site Miner, BWH, fschoen@partners.org

Evolved designs in nature offer opportunities for biomedical engineering. Jeffrey Karp will explain two biomimetic approaches currently employed. The first is in the field of biomedical adhesives using nano and microscale approaches, based on the understanding gecko mobility. Geckos attach to smooth vertical surfaces and support their weight with a single toe. The mechanism of this biological phenomenon was recently elucidated; nearly two millennia after Aristotle first reported it. The second is creating materials to capture cells mimicking the vascular endothelium’s ability to initiate cell rolling in viscous shear flow. Surface engineering through covalent immobilization of selectins can achieve long term precise control over cell rolling, which may be useful for capturing and separating cells for diagnostic and therapeutic applications.

Steering Stem Cells to Treat Osteoporosis
Robert Sackstein, MD, PhD, Associate Professor of Dermatology and of Medicine, Harvard Medical School; Head of the Translational Research Program of the Bone Marrow Transplantation Unit, Massachusetts General Hospital and the Dana-Farber Cancer Institute, rsackstein@partners.org 

Moderator: Charles A. Vacanti, MD. Anesthesiologist-in-Chief, Leroy D. Vandam/Benjamin G. Covino, Professor of Anaesthesia, Harvard Medical School; Director, Laboratories for Tissue Engineering and Regenerative Medicine, Brigham and Women's Hospital, cvacanti@partners.org

The successful clinical implementation of stem cell-based regenerative therapeutics depends critically on the ability to deliver stem cells to sites where they are needed. CD44 is a transmembrane glycoprotein that is expressed at high levels on most stem/progenitor cells. A specialized glycoform of CD44 called "Hematopoietic Cell E-/L-selectin Ligand" (HCELL) is a potent E-selectin ligand. E-selectin is an endothelial molecule that is expressed constitutively on the luminal surface of bone marrow microvascular endothelium, and is also found on post-capillary venules at all sites of tissue injury. E-selectin receptor/ligand interactions mediate shear-resistant adhesive interactions between cells in blood flow and endothelium, the critical first step in recruitment of circulating cells to any target tissue. Robert Sackstein's lab has developed a platform technology called "Glycosyltransferase-Programmed Stereosubstitution" (GPS) for custom-modifying CD44 glycans to create HCELL on the surface of living cells. Ex vivo glycan engineering of CD44 via GPS licenses osteotropism of human MSC to the bone, where these cells differentiate into osteoblasts and produce human osteoid in a NOD/SCID xenotransplant model. GPS technology thus has profound implications in therapy of generalized bone diseases such as osteoporosis, and may also be exploited for stem-cell based regenerative therapeutics for non-skeletal diseases.

Intelligent Design

Lynn Osborn just dropped this article off from the Economist. It's a great article on incentive compatibility which applies to our CIMIT Education work on collaboration.

Click here for the article

CIMIT Education

Note on Nursing Education!

Got this note from the kind folks over on a very interesting nursing blog. With all of the changes going on in medicine, the nursing profession is certainly evolving quickly:

Hi,

We just posted an article The At-Home Nurse: 101 At-Home Remedies For Common Ailments. I thought I'd bring it to your attention just in case you think your readers would find it interesting.

Thanks for your time!

Amy S Quinn

Physician-Inspired Medical Device Solutions Redux

With the goal of engaging graduate students and accelerating ideas into prototypes, teams of MIT graduate students in Electrical Engineering and Mechanical Engineering spend a semester collaborating with clinicians in CIMIT-affiliated hospitals to develop innovative medical devices. Clinicians (physicians, nurses, and scientists) present clinical problems and initial ideas on how they might be solved. Students form teams to work with the clinicians to turn these ideas into reality. The goal is for the students to deliver a working prototype and a journal-quality article in one semester. The course has been a great opportunity for clinicians to test out new ideas and to stimulate new collaborations. For example, Robopsy, a robotic device to assist radiologists performing tumor biopsies was invented by an MIT team led by Rajiv Gupta, MD, in 2004. The team has been awarded the 2007 MIT $100K prize, the world's leading entrepreneurship competition.

Moderator: Moderator: Martin Culpepper, PhD, Rockwell International Associate Professor, Mechanical Engineering, Massachusetts Institute of Technology, culpepper@mit.edu

Physician/Student Teams:

Accurate Non-Invasive Electronic Monitor for Human Body Hydration
Physician: Lynne Levitsky, MD, Associate Professor of Pediatrics, Harvard Medical School, Massachusetts General Hospital, llevitsky@partners.org
Team: Al-Thaddeus Avestruz, Michael Rinehart, Anthony Sagneri and Alexander Hayman

There is a continued need for a non-invasive method to accurately measure the level of hydration in human beings. Monitoring hydration is important to the titration of hormones, diuretics and fluids for individuals with water regulation disorders, such as diabetes insipidus, SIADH, or hypodipsia. In addition, it reduces the risk to individuals with no control over their fluid intake, such as those under intravenous feeding (G- or J-tube) or infants. Everyone involved in continued physical exertion such as athletes and military personnel, among others, are at risk of hypo- and hyperanatremia (over- and dehydration). At best, physical and possibly mental performance is below optimal.

The team's method uses low power RF energy from 100 kHz to 10 MHz to measure the loss tangent of the frontalis muscle (in the forehead). The team chose this site because of its large surface area, relatively consistent tissue profile among individuals, and copious vascularization. The loss tangent is a function of electrical conductivity and permittivity and is a material property and therefore independent of sensor electrode geometry. Studies show that the loss tangent is strongly a function of tissue osmolality and hematocrit, which are strong indicators of hydration. The group pays particular attention to the skin-electrode interface and employs a four-electrode geometry to accurately and robustly measure the localized complex impedance, from which they can derive the loss tangent, which is potentially a large improvement over other techniques which use full body impedance.

Catheter-based Device for Intra-Cardiac Mitral Valve Chord Manipulation 
Physician: Robert Levine, MD, Professor of Medicine, Harvard Medical School, Massachusetts General Hospital, rlevine@partners.org
Team: Will Boswort, Ani Mazumdar, Miguel Saez and Alex Slocum, Jr.

This project focuses on the design and implementation of a catheter-guided, intra-cardiac device that has the potential potential to help physicians mitigate the effects of mitral valve regurgitation. Mitral valve regurgitation occurs when the mitral valve becomes deformed as a result of disease or damage to the surrounding cardiac anatomy. The purpose of this device is to provide physicians with a tool that may be controlled externally and is capable of manipulating the chordae tendinae within the heart. The device is important because many patients do not have the stamina, or the required level of health necessary to survive open-heart surgery. A percutaneous procedure would be beneficial to these patients. This device could have a significant impact on the quality and length of patient’s lives, and change how physicians perform this procedure.

(For patent & rights reasons this video is being withheld for the moment - This video will be posted as soon as it becomes available)

 

Transfascial Hernia Fixation Device
Physician: Ali Tavakkoli-zadeh, MD, Instructor in Surgery, Harvard Medical School, Brigham and Women's Hospital, tavakkolizadeh@partners.org
Team: Megan Roberts, Michael Eilenberg, Jessica Galie, Rajiv Gupta, Martin Culpepper

Hernias are common surgical problems. Although hernias have been traditionally repaired by open surgery, laparoscopic repair is becoming increasingly more common. In this approach, small incisions are made in the abdominal wall, laparoscopic ports are placed, and the hernia defect repaired using a piece of prosthetic mesh. One of the most common laparoscopic hernia surgeries is laparoscopic ventral hernia repair. An important step in this operation is fixation of the mesh to the abdominal wall to prevent hernia recurrence. This fixation is usually achieved by tacking the mesh to the abdominal wall.  Several companies (e.g. Ethicon, US Surgical, Bard) produce such tacking devices, with various configurations of tacks and of differing biomaterial. Often the tacks do not provide adequate fixation, resulting in mesh migration and hernia recurrence. Many surgeons who perform this surgery reinforce the mesh by placing additional sutures. These sutures, referred to as ‘transfascial sutures’, are placed to provide long term secure fixation of the mesh to the abdominal wall. Placement of these sutures is often difficult, and results in significant pain and discomfort to the patient. This team will propose a novel way to fix a mesh to the abdominal wall during laparoscopic hernia surgery. This new device is easier to use, thus reducing operating room time and costs. It is also anticipated that this approach will result in less post-operative pain, benefiting the patient.

(For patent & rights reasons this video is being withheld for the moment - This video will be posted as soon as it becomes available)

Question & Answer

Placebo Radio Lab

Here is a funny and... Well, strange piece on the Placebo Effect as investigated from a non-clinician point-of-view.

This comes straight from New York Public Radios Radio Lab and should produce both new insight into the Placebo Effect for you as well as a few laughs.

Enjoy!

Physician-Inspired Medical Device Solutions

With the goal of engaging graduate students and accelerating ideas into prototypes, teams of MIT graduate students in Electrical Engineering and Mechanical Engineering spend a semester collaborating with clinicians in CIMIT-affiliated hospitals to develop innovative medical devices. Clinicians (physicians, nurses, and scientists) present clinical problems and initial ideas on how they might be solved. Students form teams to work with the clinicians to turn these ideas into reality. The goal is for the students to deliver a working prototype and a journal-quality article in one semester. The course has been a great opportunity for clinicians to test out new ideas and to stimulate new collaborations. For example, Robopsy, a robotic device to assist radiologists performing tumor biopsies was invented by an MIT team led by Rajiv Gupta, MD, in 2004. The team has been awarded the 2007 MIT $100K prize, the world's leading entrepreneurship competition. Join us March 4 and 11 to hear from the teams of 2007.

Moderator: Hong Ma, PhD, Postdoctoral Associate, Department of Mechanical Engineering, Massachusetts Institute of Technology, and Instructor, 2.996/6.971 Biomedical Devices Design Course, hongma@mit.edu

Physician/Student Teams:

GRIT Chair Alarm
Lauren Kattany, RN, Clinical Nurse Specialist, Massachusetts General Hospital, lkattany@partners.org 
Students: Heather Knight, Jae-Kyu Lee

The Gesture Recognition Interactive Technology (GRIT) Chair Alarm aims to improve the state-of-the-art of chair and wheelchair alarms to prevent falls for patients at risk by recognizing the gesture of a patient attempting to stand. Patient falls are one of the greatest causes of injury in hospitals. Due to recent changes in medical insurance rules, hospitals may no longer be reimbursed for fall-related injury, which means that hospitals must act quickly to expand patient fall prevention measures. Existing chair and bed exit alarm systems are inadequate because of insufficient notification, high false-alarm rate, and long trigger delays. The GRIT chair alarm uses an array of proximity sensors and pressure sensors to create a map of the patient’s sitting position, and then uses gesture recognition algorithms to determine when a patient is attempting to stand up. The system responds with light and voice alarms that can encourage the patient to remain seated and/or to make use of the system’s integrated nurse-call function. The team's solution can be seamlessly integrated into existing hospital WiFi network, sending messages to the nurse call system as well as providing the patient’s location. These technologies could also be expanded to monitor patient activity in other medical settings and emergent applications.

SmartPad – A Wireless, Stickerless EKG System
Rob Sheridan, MD, Chief, Burn Surgery Service, Shriners Hospital for Children; Co-Director, Sumner Redstone Adult Burn Unit, Massachusetts General Hospital, rsheridan@partners.org
Students: Fred Chen, Pei-Lan Hsu, Brad Stronger, Henry Wu, Hong Ma

During an operation, the patient's vital signs are displayed in the operating room so that doctors can monitor them. In order to obtain the data, adhesive electrodes are applied to the patient, and wires are run from the patient to the display monitors. The large number of wires attached to the patient inhibits the medical team's access to the patient, and the adhesive can fail in adverse conditions. Additionally, electrodes are often placed on the arms, legs, or back due to trauma in the ideal locations, especially for burn victims.

To help doctors more efficiently treat their patients, this team presents the SmartPad: a device that displays a patient's electrocardiogram (EKG) signal without adhesives or wires.  Instead, sensors are bonded to a foam mat, on which the patient lies during the operation. Software scans through the redundant array of sensors and selects the optimal set for each patient's size and position. One is able to display an EKG waveform which, while inferior to a cardiologist's EKG, is sufficient for the doctor to monitor the patient's health.

Hand-held Endotracheal Tube Placement Sensor
Rob Sheridan, MD, Chief, Burn Surgery Service, Shriners Hospital for Children; Co-Director, Sumner Redstone Adult Burn Unit, Massachusetts General Hospital, rsheridan@partners.org
Students: Keith Durand, Byron Hsu, Brandon Pierquet, Warit Wichakool

The endotracheal tube (ETT) is ubiquitous in hospitals. Placing the tube at the correct location in the throat requires a high level of skill and training, and it is secured in place with a variety of tape or tie systems. Unplanned displacement of the tube can result in patient death and emergency reintubation is difficult. Constant bedside supervision can be done but is impractical. Currently, there are no economical and convenient means of verifying the tube’s position in a patient’s throat. This team has developed a hand-held ETT placement sensor, which is a portable device that allows a doctor or nurse to “see” the tube’s position in the throat. The device uses a two-dimensional array of Giant Magnetoresistance (GMR) sensors to localize the position of a tiny magnet embedded into the ETT. As the sensor is held over the sternal notch, the sensor unit measures a magnetic filed strength underneath the sensing area. An on-board microprocessor displays an intuitive, color-coded map on an LCD screen. The device provides a real-time information for locating the tube position. In addition, the device is designed to fit comfortably into a hand or pocket and run off an internal rechargeable lithium-polymer battery. An integrated wireless module allows the device to be adapted for continuous monitoring and automated notification of hospital staff if a potential problem is detected.