Biomechanical Tissue Stimulator Matt Brady (BME/EE) Ankeet Choxi (BME) Misha Kotov (CS) Steven Manuel (ME) Adviser: Dr. V. Prasad Shastri

Overview  Stimulates tissue mechanically  Promotes growth of tissue engineered cartilage

What are we stimulating?  Articulate cartilage covers human joint surfaces transfers mechanical load to skeletal system makes up ~2% of tissue volume in human body

Persistent medical problems  Limited ability to self- repair  Osteoarthrosis and related problems very common  100,000 AC injuries annually

Why stimulate?  Positive response to mechanical stimulation  Biomechanical stimulator delivers controlled amount of force  Measured results

Past Work Ongoing cell-culture research project Prototype of stimulator has been constructed Many problems incurred Much research done for design of new device Range of force Sensors Detection and environment

Current Work  Finalizing design specifications Purchasing appropriate hardware/software  Equipment consideration: Motor to drive device and design Controller system for motor Power Supply Multiple sensors Data Acquisition and Device Calibration

Design Parameters  Accuracy of 20 microns  Stimulation frequency of 1 Hz max  Max load of 1 MPa or 100 N per sample  12 wells at once  Max in-test stroke of 1 mm  100 percent humidity at 98°F

Well plate with samples Platen Stepper Actuator Teflon pistons Device Structure

Programming objectives  Program an application provide the following: Control the motor(s) Calibrate the sensors Gather relevant data  Help on interface with standalone control unit

LabVIEW!  Acquire, analyze, present data  Graphical development environment  Measurement and control services  Virtual instrumentation

Application considerations  Based on the number of samples, display appropriate distribution pattern  Display where contact was made and with how much force; determine baseline displacement  Allow for customized routines, be able to save and repeat procedures  Update experiment figures in real time  Provide exception handling routines  Communication with standalone control unit

Motor Controller  Brain of the motor  Mediator between computer and motor  Takes computer program and runs motor at desired speed and step  May run as slave or master

Power Supply  Powers individual components of system  Need to know what voltage and current each part runs on to determine what power supply can be used and for which components

Displacement Sensor  Will output measurements of displacement  Needed to determine amount of strain applied to each tissue sample  Contact Sensor

Future Work  Finalizing the device design  Ordering necessary hardware to begin construction on device prototype  Beginning construction of frame to place tissue culture samples into

Summary  Articulate cartilage and problems  Biomechanical tissue stimulator Mechanically stimulates cartilage Promotes growth of tissue  Design, considerations