High-frequency rheology system
Rheology system. The system includes a first piezoelectric actuator assembly for providing microscale displacement of a sample and a second piezoelectric actuator assembly for oscillating the sample at a nano/micro scale displacement in a selected frequency range extended significantly as compared to the frequency range available on the commercial AFMs. A preferred sample is cartilage and the disclosed system can distinguish between normal cartilage and GAG-depleted cartilage.
1. A rheology system comprising:
a first piezoelectric actuator assembly for providing microscale displacement of a sample; and
a second piezoelectric actuator assembly for oscillating the sample at a nanoscale/microscale displacement in a selected frequency range wherein the second piezoelectric actuator assembly comprises:
a beam for supporting the sample;
a substrate to which the beam is affixed in a spaced-apart relation; and
a piezoelectric actuator positioned between the substrate and the beam to cause the beam to oscillate at a selected frequency and displacement upon piezoelectric actuator actuation.
2. The system of claim 1 wherein the second piezoelectric actuator is pre-loaded against the beam.
3. The system of claim 1 wherein the selected frequency is in the range of 1 Hz to 200 kHz.
4. The system of claim 1 wherein the nanoscale displacement is approximately 1 nm.
5. The system of claim 1 wherein the beam is made of carbon fiber.
6. The system of claim 1 further including a mica layer between the beam and the sample.
7. The system of claim 1 wherein the sample is cartilage.