Evaluation of the feasibility of biodegradable polymers for encapsulating resonance circuits
Antniemi, Anni (2016)
Antniemi, Anni
2016
Materiaalitekniikan koulutusohjelma
Teknisten tieteiden tiedekunta - Faculty of Engineering Sciences
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Hyväksymispäivämäärä
2016-06-08
Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi:tty-201605254064
https://urn.fi/URN:NBN:fi:tty-201605254064
Tiivistelmä
The properties and the structure of biodegradable polymers alter during degradation. The conventional way to study material properties and degradation requires direct contact with the material. For example monitoring the degradation of biodegradable implants inside a human body is challenging. Changes in the biodegradable polymers can be wirelessly monitored using resonance circuits. However, the circuits have to be protected from the surrounding environment in order for them to work properly. A protective layer around the circuit prevents water penetration to the circuits and enables observing the material changes.
The aim of this work was to evaluate the feasibility of three biodegradable polymers for encapsulating resonance circuits. The circuits were encapsulated by poly(L-lactide-co-glycolide) (PLGA 80/20), poly(D,L-lactide-co-glycolide) (PDLGA 85/15), and poly(L-lactide-co-glycolide) (PLGA 10/90) using compression molding. The resonance behaviors of the encapsulated circuits were wirelessly measured in order to evaluate the success and the duration of the encapsulation. In addition, a degradation test series was carried out to compare the resonance behavior and the degradation. The comparison was done in order to find out if changes in material properties could be obtained by measuring wirelessly the resonance behavior of the encapsulated circuits.
The study revealed that the encapsulation using compression molding was possible with PLGA 80/20 and PDLGA 85/15 materials. The PLGA 80/20 capsules worked even for 14 weeks and the PDLGA 85/15 capsules for 7 weeks. The PLGA 10/90 capsules lasted only few days and failed due to rapid degradation of the capsules. The degradation test showed that the properties and the appearance of the PLGA 80/20 hardly changed. The properties of the PDLGA 85/15 decreased continuously during the degradation test and were weaker than the properties of the PLGA 80/20. The structure of the PDLGA 85/15 samples changed significantly due to autocatalysis. The study also revealed that the properties of the PLGA 10/90 samples were the weakest and the samples were totally fragmented after six weeks.
The visual characterization of the encapsulated circuits and the degradation test samples suggested that water absorption could have caused the characteristic resonance behavior of each material. However, the results from the degradation test series do not explain the resonance behavior even though some similarities could be obtained. Consequently further studies are needed to solve the reason for the resonance behavior.
The aim of this work was to evaluate the feasibility of three biodegradable polymers for encapsulating resonance circuits. The circuits were encapsulated by poly(L-lactide-co-glycolide) (PLGA 80/20), poly(D,L-lactide-co-glycolide) (PDLGA 85/15), and poly(L-lactide-co-glycolide) (PLGA 10/90) using compression molding. The resonance behaviors of the encapsulated circuits were wirelessly measured in order to evaluate the success and the duration of the encapsulation. In addition, a degradation test series was carried out to compare the resonance behavior and the degradation. The comparison was done in order to find out if changes in material properties could be obtained by measuring wirelessly the resonance behavior of the encapsulated circuits.
The study revealed that the encapsulation using compression molding was possible with PLGA 80/20 and PDLGA 85/15 materials. The PLGA 80/20 capsules worked even for 14 weeks and the PDLGA 85/15 capsules for 7 weeks. The PLGA 10/90 capsules lasted only few days and failed due to rapid degradation of the capsules. The degradation test showed that the properties and the appearance of the PLGA 80/20 hardly changed. The properties of the PDLGA 85/15 decreased continuously during the degradation test and were weaker than the properties of the PLGA 80/20. The structure of the PDLGA 85/15 samples changed significantly due to autocatalysis. The study also revealed that the properties of the PLGA 10/90 samples were the weakest and the samples were totally fragmented after six weeks.
The visual characterization of the encapsulated circuits and the degradation test samples suggested that water absorption could have caused the characteristic resonance behavior of each material. However, the results from the degradation test series do not explain the resonance behavior even though some similarities could be obtained. Consequently further studies are needed to solve the reason for the resonance behavior.