Elsevier

Materials Letters

Volume 61, Issue 13, May 2007, Pages 2601-2605
Materials Letters

Preparation and characterization of collagen-modified polylactide microparticles

https://doi.org/10.1016/j.matlet.2006.10.006Get rights and content

Abstract

To improve cytocompatibility of polylactide (PLA) and to obtain an injectable scaffold for tissue engineering, collagen-modified PLA (CPLA) microparticles were prepared. Poly-(α-methacrylic acid)-grafted PLA (PMAA-PLA) was obtained by photooxidization and UV induced polymerization. Suspension of PMAA-PLA microspheres with an average size of 172.8 ± 3.6 nm was prepared with solvent evaporation technique. CPLA microparticles were prepared by adding collagen acetic acid solution into PMAA-PLA microsphere suspension prepared above. FTIR spectrum of PMAA-PLA confirmed that PMAA had been grafted on PLA surface. Analytical results of FTIR, XPS, SEM, hematoxylin and eosin (HE) stained and zeta potential measurement showed that the CPLA microparticles obtained by modifying PMAA-PLA microspheres with collagen molecules uniformly have a microporous structure and a particle size of less than 100 μm. The CPLA microparticles were expected to be used as an injectable scaffold for tissue regeneration.

Introduction

Tissue engineering is a promising approach to repair damaged tissues/organs such as cartilage, skin and bone, in which a number of synthetic polymers have been used as scaffold materials. Polylactide (PLA) is one of the most common polymers due to its advantages such as nontoxicity, processibility and biodegradability. However, its cytocompatibility needs to be improved because its hydrophobicity retards cell attachment [1], [2]. One approach to improve its cytocompatibility is to introduce collagen onto the surface of PLA through surface modification because collagen can specifically bind with integrins on cell membrane, which can effectively accelerate cell attachment and spreading [3], [4], [5], [6], [7], [8], [9], [10].

Injectable scaffold has attracted more and more research interests among tissue engineering scaffolds because of its easiness of being transplanted [10], [11], [12], [13]. In this study, collagen-modified PLA (CPLA) microparticles were prepared by adding collagen solution into PMAA-PLA microsphere suspension. The obtained CPLA microparticles are expected to be used as an injectable scaffold for tissue regeneration.

Section snippets

Preparation of CPLA microparticles

Poly (α-methacrylic acid) (PMAA) was introduced onto the PLA surface using a grafting polymeric method as described previously [14]. The PLA particles (medical grade, purchased from Dikang Biomedical Co., Ltd, China) were immersed in hydrogen peroxide solution (30%, AR) and irradiated with UV light for 50 min to introduce –OOH groups onto the surface of PLA particles. The photooxidized particles were rinsed with deionized water to remove excess hydrogen peroxide and then immersed into

The measurement of particle size and zeta potential

The average particle size and zeta potential of the PMAA-PLA microspheres in the suspension obtained were shown in Table 1. The size of PMAA-PLA microspheres was from 59 nm to 615 nm (Fig. 1). The absolute value of zeta potential of PMAA-PLA microsphere suspension was much higher than 30 mV, which meant that the PMAA-PLA microspheres in the suspension were not readily conglomerated [16]. Therefore, the PMAA-PLA microsphere suspension with an average particle size of 172.8 ± 3.6 nm could stably

Conclusion

Carboxyl groups were introduced onto inert PLA surface through UV induced grafting of PMAA. Subsequently collagen-modified PLA microparticles with microporous structure were successfully prepared through interactions between PMAA-grafted PLA microspheres and collagen molecules. FTIR, XPS, SEM, HE stained and zeta potential measurement confirmed the occurrence of modification of collagen on PLA surface. These collagen-modified PLA (CPLA) microparticles are supposed to support the attachment and

References (19)

  • A.G. Mikos et al.

    Biomaterials

    (1994)
  • Z.W. Ma et al.

    Eur. Polym. J.

    (2002)
  • H. Suh et al.

    Biomaterials

    (2001)
  • Z.W. Ma et al.

    Biomaterials

    (2005)
  • A. Ide et al.

    Mater. Sci. Eng., C, Biomim. Mater., Sens. Syst.

    (2001)
  • Y. Yang et al.

    Nucl. Instrum. Methods Phys. Res., B Beam Interact. Mater. Atoms

    (2003)
  • T. Sato et al.

    Mater. Sci. Eng., C, Biomim. Mater., Sens. Syst.

    (2004)
  • Y. Hong et al.

    Biomaterials

    (2005)
  • A.S. Hoffman

    Adv. Drug Deliv. Rev.

    (2002)
There are more references available in the full text version of this article.

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