Event Abstract

Surface modification of polylactide by a biodegradable polycarbonate with antithrombogenicity

  • 1 fukushima labolatory, yamagata university graduate school of science and engineering, Japan
  • 2 institute for materials chemistry and engineering, kyushu university, Japan

Introduction: Poly(L-lactide) (PLLA) has been widely studied as biodegradable biomaterials for applications in tissue engineering and regenerative medicine.[1] However, PLLA is not used under the blood-contacting condition because of platelet adhesion. Poly(2-methoxyethyl acrylate) (PMEA) is known as an excellent antithrombotic material, commercializing for the oxygenetar coating. We have previously developed a biodegradable polycarbonate poly(2-methoxyethyl 2-methyltrimethylene carbonate carboxylate) (PMEMTC) that demonstrats decennnt antithrombogenicity.

However, the PMEMTC can not be used for bulk applications alone because its mechanical strength is quite low. Thus, we designed a composite of PLLA coated by PMEMTC on the surface to create a biodegradable material having both the mechanical strength and blood compatibility. Furthermore, we exploit stereocomplex, which is specific intermolecular interaction between PLLA and poly(D-lactide) (PDLA), for improving interpolymer adhesion between the PLLA substrate and PMEMTC coating. In particular, a triblock copolymer PDLA-b-PMEMTC-b-PDLA is prepared and coated on a PLLA substrate.

Results and Discussion: In this study, the triblock copolymer was synthesized by sequential ring-opening polymerizations of ME-MTC, a monomer for PMEMTC, and D-lactide (Yield 93 %, Mn 18000, ÐM 1.10). Then, the polymer was spin- coated on a PET substrate for further tests. As control samples, PET, PLLA, PMEA, PMEMTC were used in this study to compare the surface properties and blood compatibility. A contact angle against water for the triblock copolymer (PDLA-b-PMEMTC-b-PDLA) using a sessile drop indicated a similar value to that for PLLA.

By contrast, a contact angle of PDLA-b-PMEMTC-b-PDLA by captive bubble method exhibited a similar value to that of PMEMTC. This result suggests that wettability of the surface of PDLA-b-PMEMTC-b-PDLA may change upon contacting with water. An intersitng results were obtained in a human platelet adhesion test where PDLA-b-PMEMTC-b-PDLA showed  a suppressed platelet adhesion  that is comparable with that observed for PMEMTC.

In addition, a similarly low platelet adhesion was confirmed for the PLLA substrate coated by PDLA-b-PMEMTC-b-PDLA. As a consequence, we were successful in surface modification of PLLA, imparting antithrombogenicity. From this result, it turns out that central PMEMTC segment of PDLA-b-PMEMTC-b-PDLA dominantly plays a role in determining surface wettability and platelet adhesion, probably by covering the surface upon swelling. We also found that the triblock copolymer possesses higher interpolymer adhesion on the PLLA substrate than homo PMEMTC.

Conclusion: A block copolymer of PMEMTC and PDLA, PDLA-b-PMEMTC-b-PDLA, was successfully synthesized. Interstingly, the platelet adhesion on the PDLA-b-PMEMTC-b-PDLA was comparable with that on homopolymer PMEMTC, in spite of including hydrophobic and thrombotic PDLA segments at both ends. Moreover, this triblock copolymer demonstrated a high interpolymer adhesion based on stereocomplex. Therefore, the surface modified PLLA by this triblock copolymer could open a new window for antithrombotic biodegradable devices.

japan society for the promotion of science

References:
[1] K. Fukushima et al., Polym. Int., 2006, 55, 626-642.

Keywords: blood vessel, Biocompatibility, Surface modification, Biodegradable material

Conference: 10th World Biomaterials Congress, Montréal, Canada, 17 May - 22 May, 2016.

Presentation Type: Poster

Topic: Biomaterials for cardiovascular applications, vascular grafts and embolic devices

Citation: Haga Y, Inoue Y, Tanaka M and Fukushima K (2016). Surface modification of polylactide by a biodegradable polycarbonate with antithrombogenicity. Front. Bioeng. Biotechnol. Conference Abstract: 10th World Biomaterials Congress. doi: 10.3389/conf.FBIOE.2016.01.01401

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Received: 27 Mar 2016; Published Online: 30 Mar 2016.