Particle Characterization

Service Overview

The OIC performs particle characterization on polyethylene particles formed during simulation wear testing, pin-on-disc testing, and biomechanical testing. Sample serum is collected at any given test interval, then processed for particle characterization through chemical digestion, filtration, sputter coating, microscopic imaging, elemental composition analysis, and image processing.

Performing particle characterization on wear test particles is beneficial for understanding material behaviour and immunologic response.

Additional Information

What equipment do you use for carrying out particle characterization?

Digested and filtered polyethylene particles are sputter coated with gold in a controlled vacuum gas environment in preparation for image analysis. Coated filters are carefully examined for particles using a scanning electron microscope (SEM), where high definition microscopic images are taken for particle characterization. Our SEM is equipped with energy-dispersive x-ray spectroscopy (EDS) for elemental composition verification of particles.

How are particles characterized?

Particles are characterized through advanced image processing software on the captured SEM images. Particles are auto-detected though manual greyscale thresholding and bit-plane filtering, then analyzed to determine precise particle size and morphology. Particle characterization may include measurements of area, aspect ratio, form factor, roundness, length, perimeter, ferret average, and equivalent circular diameter.

What other capabilities does your technology have?

Particle characterization may also be performed on metal particles such as additive manufacturing powders. Metal powder morphology and particle size are critical for quality control and material assessment.

Standards We Test

ASTM F1877-16

Standard Practice for Characterization of Particles

ASTM F561-19

Standard Practice for Retrieval and Analysis of Medical Devices, and Associated Tissues and Fluids

ASTM WK66030

New Guide for Quality Assessment of Metal Powder Feedstock Characterization Data for Additive Manufacturing

ISO 17853: 2011

Wear of implant materials – Polymer and metal wear particles – isolation and characterization