Biodegradable encapsulation for inductively measured resonance circuit

The feasibility of biodegradable encapsulation for LC resonance circuits is studied. The used biodegradable polymers are polycaprolactone (PCL) and poly-L-lactide/caprolactone (PLCL). The encapsulated circuits are immersed in a phosphate buffer solution and the phase and magnitude responses are measured by using an inductive link during an 80-day test period. The features derived from the resonance curves are extracted and studied. The features change fast when the encapsulation absorbs water during the first days of immersion. After the initial water intake, there is a drift in the extracted estimates for the resonance frequency. The drift of the frequency of the resonance circuit in PLCL is faster compared with the drift of a circuit in PCL. The resonance curve of the PLCL specimen also diminished to undetectable after 72 days of immersion. The resonance curves of the sample in PCL were easily detectable throughout the test period. The achieved results promote further studies based on this concept in order to monitor biodegradable polymers and their properties.