Philadelphia Medical Device Laboratories

The Philadelphia Laboratory is proudly recognized as an A2LA (ISO 17025) accredited lab.  While all of our practices, policies and procedures uphold the basic principles of good laboratory procedures, a select group of our procedures are specifically A2LA accredited. Our certificate of accreditation and list of accredited procedures can be found here.

The focus areas of our facilities include the following:

Mechanical Testing Facility

The mechanical testing facility is equipped with two servo-hydraulic load frames capable of up to 4 inches of displacement and loads ranging from 50 lbs to 3000 lbs. Additionally, we have an electromechanical frame capable of 40 inches of displacement and load cells ranging from 20 lbs to 6500 lbs. The lab also has a custom small-force, small-displacement load frame that can be used for testing applications requiring gram-force and micron-displacement resolution.

Figure 1. Cadaveric Pelvis Testing

In addition to biomaterials characterization, we also have capabilities to evaluate spinal technologies, perform wear testing (see below), conduct accelerated aging protocols, and utilize cadaveric models for evaluating medical device technologies.

Tribology

The lab contains an MTS spine-wear simulator. This system conforms to both the ASTM and ISO total disc replacement wear-test standards. Additionally, we have developed custom protocols on this system to test nucleus pulposus replacement materials, flexion- and extension-limiting devices, and validated wear-test protocols with retrieved components. In addition to the spine-wear simulator, the lab has an AMTI Orthopod and a biaxial polyethylene wear tester. To accompany these systems, the lab has a full range of balances to perform gravimetric assessments, and the microscopy facilities (see below) to provide full documentation of components before, during, and after each test.

Biosafety Level 2 Suite

This facility contains a full-service cadaveric storage, dissection, and procedure suite. Here company representatives, surgeons, and Exponent staff can dissect and prepare tissues for evaluation of medical technologies. The suite is equipped with a fluoroscope, tissue band saw, and all of the necessary universal precautions and disposables needed to carry out cadaver-related activities. The lab is also equipped with freezer and refrigerator storage for both human and animal samples.

Microscopy Facility

The microscopy facility contains a full suite of digital imaging microscopes with a variety of lighting options. We have macro- and microscopes with wide ranges of resolution and fields of view. In addition we have a Zygo New View 5000 surface interferometer and a Thermo Nicolet FTIR spectrometer, complete with microscope and ATR attachment. In addition to these imaging capabilities, Exponent staff also has access to area academic SEM and ESEM facilities that are within walking distance of the office.

Polymer Characterization

                  Figure 3A                                                                                      Figure 3B 

Figure 3C

Figure 3. (A) Oxidation Analysis of a sample taken from a retrieved total knee replacement. (B) Spectral map and

 (C) spectra are used to quantify the degree to which the sample has oxidized.

Specifically, we have experience with the stage I and stage II analyses for polyethylene, listed below as Tables 1 and 2 (referenced from the UHMWPE Handbook). In addition, we have experience with modification of these methods to apply them to polycarbonate urethanes, PEEK, and other polymers for medical device applications. 
 

Table 1. Tests required by the FDA for a new polyethylene submission

Table 2. Common test techniques used to assess the various properties of UHMWPE. The superscripts indicate which tests are suitable for the polyethylene in a powder state, after consolidation, and after crosslinking via irradiation.

 ¹ Powder state ² Consolidated ³ Post-irradiation

Metals Characterization 

The Philadelphia Labs also permit metals characterization through microscopy, and hardness and micro-hardness characterization. Samples can be cut, mounted, polished and etched as metallographic samples, to characterize the microstructure of materials, identify cracking, and analyze deposits. Trained personnel also have experience with embedding materials for characterization using both SEM and TEM. Area academic SEM and ESEM facilities are equipped with EDS detectors for chemical composition measurements. Additional chemical techniques include traditional FTIR techniques and ATR-FTIR techniques. The Philadelphia office is conveniently located near local machine shops that can provide short-turnaround sample alterations or fixtures.    

Recently added to the suite of capabilities is electrochemistry. Equipment includes various sizes of sample holders, test cells, and a calibrated potentiostat. This allows trained personnel to make dynamic current and voltage measurements to characterize the corrosion behavior of devices and materials. This system can be integrated with the mechanical test equipment to make measurements during fatigue testing.

Electrical Testing Lab

Philadelphia’s electrical testing lab allows for rapid testing of electronic devices and systems. Testing equipment includes a deep memory digital storage oscilloscope, power supplies, function generators, data acquisition modules, and various handheld meters for making measurements in the lab or off site. ESD safe bench and an SMD and through-hole rework station are also available. Capabilities can be expanded for specific project needs. Access to x-ray, CT, and SEM/EDS facilities is also available through local academic labs and remote-view systems in other Exponent labs.