Water-soluble synthetic biocompatible polymer support for a neural deep probe
Deng, Siyuan Jr (2015)
2015
Master's Degree Programme in Biomedical Engineering
Luonnontieteiden tiedekunta - Faculty of Natural Sciences
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Hyväksymispäivämäärä
2015-12-09
Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi:tty-201511231746
https://urn.fi/URN:NBN:fi:tty-201511231746
Tiivistelmä
The objective of this thesis is to search one or several biocompatible, water-soluble polymeric materials using as support for a neural deep probe which has been manufac-tured by the Center of Microelectronics in Provence as a brain implanted electrode. However, flexible character of the probe limits the brain implantation procedure. In this case, water-soluble and rigid material is requested as a support for the neural deep probe. In this study, only the water-soluble polymer which has been used in brain tissue was considered. PLLA-PEG-PLLA triblock copolymer, PVP and PVA were selected due to the good biocompatibility, water solubility and existent brain implantation history.
A series of PLLA-PEG-PLLA triblock copolymers were synthesized with various PEG/PLLA unit ratios in order to achieve the modification of solubility and mechanical properties. Then the synthesized triblock copolymers were characterized by 1H-NMR and DSC. The measurement of water solubility of the materials was carried out by in vitro dissolution test in PBS for 1 day. Meanwhile, mechanical properties of the materi-als were performed by tensile test. The polymer samples for dissolution test and tensile test were prepared by melting compression for PLLA-PEG-PLLA and solvent casting for PVA and PVP. Subsequently, the polymers were combined with and removed from neural deep probe by solvent casting and PBS washing respectively.
The result indicates that the PEG block can modify the hydrophilicity of the PLLA-PEG-PLLA copolymer while the mechanical properties of the copolymer can be dominated by PLLA block. PLLA14-PEG795-PLLA14 stood out from all the synthesized triblock copolymers to be as a candidate for the support because of providing both good water solubility and better Young’s modulus. Meanwhile, PVA and PVP were also proved qualified for the support due to the good water solubility and excellent rigidity. The combination test with parylene C reveals that the polymer film can be bonded with the probe by solvent casting then released without damage of the probe. The results suggest that these three polymers are possible to be used as support for the neural deep probe. The future study will be continued in the Center of Microelectronics in Provence.
A series of PLLA-PEG-PLLA triblock copolymers were synthesized with various PEG/PLLA unit ratios in order to achieve the modification of solubility and mechanical properties. Then the synthesized triblock copolymers were characterized by 1H-NMR and DSC. The measurement of water solubility of the materials was carried out by in vitro dissolution test in PBS for 1 day. Meanwhile, mechanical properties of the materi-als were performed by tensile test. The polymer samples for dissolution test and tensile test were prepared by melting compression for PLLA-PEG-PLLA and solvent casting for PVA and PVP. Subsequently, the polymers were combined with and removed from neural deep probe by solvent casting and PBS washing respectively.
The result indicates that the PEG block can modify the hydrophilicity of the PLLA-PEG-PLLA copolymer while the mechanical properties of the copolymer can be dominated by PLLA block. PLLA14-PEG795-PLLA14 stood out from all the synthesized triblock copolymers to be as a candidate for the support because of providing both good water solubility and better Young’s modulus. Meanwhile, PVA and PVP were also proved qualified for the support due to the good water solubility and excellent rigidity. The combination test with parylene C reveals that the polymer film can be bonded with the probe by solvent casting then released without damage of the probe. The results suggest that these three polymers are possible to be used as support for the neural deep probe. The future study will be continued in the Center of Microelectronics in Provence.