Typical chemical characterization workflow; Devices/coupons are extracted with different solvent systems at different temperatures. Generated extracts are analyzed using different analytical techniques such as GC/MS, LC/MS and ICP/ MS. Various data processing software packages and spectral databases are used to identify and quantify the extractables.
Our research program is designed to translate advances in analytical technology into protocols for the regulatory screening of device contaminants and chemical characterization.
The following studies are currently underway utilizing advanced analytical techniques:
- Chemical Characterization
Medical device materials contain substances that can produce adverse health effects in patients if released from the device in sufficient quantities. A chemical characterization/risk assessment approach is being increasingly used for the biological safety assessment of medical devices, which is expected to reduce use of animals for toxicity and biocompatibility testing. FDA Center for Devices and Radiological Health (CDRH) began conducting strategic scientific studies that will enable FDA to recommend optimal analytical methods to conduct these chemical analyses.
- Mass spectrometry for contaminant detection
Separation-based mass spectrometry (e.g., liquid chromatography and capillary electrophoresis) is implemented and protocols are refined to detect a selected array of contaminants in increasing sensitivity.
- Ambient mass spectrometry for high-throughput screening
Development of measurement protocols for different ambient mass spectrometry techniques [e.g., desorption electrospray ionization (DESI), paper spray and direct analysis in real time (DART)] to decrease the sample analysis time and reduce the complexity of analytical measurements. Some representative examples include screening of potentially contaminated heparin coatings on catheters and stents and endotoxin detection in ophthalmic devices.
- Chemical characterization of aerosol generated from electronic nicotine delivery systems (ENDSs)
Characterization of aerosols generated by ENDSs as a function of temperature, number of puffs, e-juices, brands etc. using sophisticated analytical methods (liquid and gas chromatography and mass spectrometry, inductively coupled plasma mass spectrometry) for a complete chemical characterization (carbonyl compounds volatile/semi-volatile compounds and heavy metals) of these aerosols.
Current funding sources:
- Medical Counter Measurement initiative (MCMi)
- Critical Path Funding
George Washington University
Thayer School of Engineering- Dartmouth College
Samanthi Wickramasekara, PhD
Berk Oktem, PhD
Steve Wood, PhD
Keaton Nahan, PhD- ORISE fellow
Gang Peng (Peter)- ORISE fellow
Mandy Tran- ORISE fellow
Kushbu Amin- Pathways intern
- Agilent 6540 accurate mass Q TOF mass spectrometer with Agilent 1260 nano LC system
- Thermo LCQ-FLEET ion trap mass spectrometer
- Thermo LTQ-XL ion trap mass spectrometer withAccela 1250 LC system
- MassTech MTE 50 portable mass spectrometer
- Agilent 6890N GC
- Agilent 7100 Capillary Electrophoresis system
- Shimadsu HPLC system
- IonSense DART 100 SVP ionization source
- OmniSpray DESI source
- Ion Torrent Next Generation Sequencing machines
- Luminex xMAP technology
- Agilent- MassHunter, MassProfiler, Spectrum Mill
- Thermo- X caliber, SIEVE
- Metlin MS library
Public Domain Software:
Relevant Standards & Guidances
- ISO 10993-12: Biological evaluation of medical devices
- ISO 10993-18: Chemical characterization of materials
Selected peer-review publications
- Wang et al. “Analytical Chemistry in the Regulatory Science of Medical Devices”- Reviews in Analytical Chemistry. 2018
- Ludwig et al “Characterizing the Free Volume of Ultrahigh Molecular Weight Polyethylene (UHMWPE) to Predict Transport Coefficients in Orthopedic Liners” J Biomed Mater Res B Appl Biomater. 2017
- Lucas AD, et al. “Solvent or thermal extraction of ethylene oxide from polymeric materials: Medical device considerations”. J Biomed Mater Res. 2017, 1(4):91–9.
- Li et al. “Rapid detection of bacterial endotoxins in ophthalmic viscosurgical device materials by direct analysis in real time mass spectrometry” Analytica Chimica Acta, 2016
- Hongli Li, et al. "Direct Analysis of Endotoxin in Real Time by Mass Spectrometry" Anal Chim Acta. 2016 Nov 2; 943:98-105.
- H Li et al. “One-Hour Screening of Adulterated Heparin by Simplified Peroxide Digestion and Fast RPIP-LC-MS” - Analytical chemistry, 2015
- Nemes et al., High-Throughput Differentiation of Heparin from other Glycosaminoglycans by Pyrolysis Mass Spectrometry. Anal Chem., 2013.
- Choi et al., Contamination of Ultrapure Water with Bisphenol A Leached from Polysulfone Ultrafilter. Talanta,. 2012.
- Lucas et al., Extraction and Stability of Ethylene Oxide Residue in Medical Devices. Biomedical Instrumentation & Technology. 2008.