Elsevier

Materials Letters

Volume 64, Issue 21, 15 November 2010, Pages 2299-2301
Materials Letters

Calcium phosphate/block copolymer hybrid porous nanospheres: Preparation and application in drug delivery

https://doi.org/10.1016/j.matlet.2010.07.060Get rights and content

Abstract

Calcium phosphate (CaP)/block copolymer hybrid porous nanospheres were synthesized by a simple solution method using CaCl2 and (NH4)2HPO4 in the presence of a block copolymer at room temperature. X-ray diffraction showed that the sample consisted of amorphous calcium phosphate (ACP). The BET specific surface area and the pore size distribution of the CaP/PLLA-mPEG hybrid porous nanospheres were also characterized. The as-prepared CaP/PLLA-mPEG hybrid porous nanospheres were explored as drug carriers, and showed a high ibuprofen loading capacity and in vitro prolonged drug release behavior in a simulated body fluid. These CaP/block copolymer hybrid porous nanospheres exhibit a great potential for application in drug delivery.

Introduction

As the principal inorganic component of bones and teeth, calcium phosphate (CaP) is considered as an ideal biomaterial for various biomedical applications due to its excellent biocompatibility and biodegradability [1], [2]. In the past few years, CaP nanomaterials have attracted a great deal of attention in the field of biomedicine. Recently, uniform and well-dispersed CaP nanoparticles were synthesized under the concept of van der Waals chromatography (vdW-HPLC laundering), and these CaP nanoparticles performed well in the application of in vitro imaging and drug delivery after binding with various kinds of organic molecules [3], [4], [5]. Polymer-functionalized CaP nanoparticles were also prepared and they were used as efficient carriers for photodynamic therapy [6].

CaP hollow nanostructures are considered to be advantageous because of their large specific surface area and high capacity for loading drug, protein or DNA molecules. Several methods have been employed to prepare CaP hollow nanostructures, for example, polyelectrolyte-mediated mineralization [7], [8], template approaches [9], [10], [11], ultrasonic-assisted route [12], etc. However, there have been few fabrication methods reported for CaP porous nanostructures. To satisfy the increasing demand of biomedical applications, it is essential to develop facile ways for the synthesis of CaP porous nanostructures.

Herein, we report a facile room-temperature solution method for the synthesis of calcium phosphate (CaP)/block copolymer hybrid porous nanospheres using CaCl2 and (NH4)2HPO4 in the presence of a block copolymer. The as-prepared CaP/PLLA-mPEG hybrid porous nanospheres were explored as drug carriers, and showed high ibuprofen loading capacity and in vitro prolonged drug release behavior in a simulated body fluid.

Section snippets

Experimental section

The block copolymers used in this work were poly(dl-lactide-co-glycolide)-block-monomethoxy(polyethyleneglycol) (PLGA-mPEG), poly(l-lactide)-block-monomethoxy(polyethyleneglycol) (PLLA-mPEG), and poly(l-lactide)-block-polyethyleneglycol-block-poly(l-lactide) (PLLA-PEG-PLLA), and they were synthesized according to a method reported in the previous publication [13]. For PLGA-mPEG, the molecular weight of the PEG segment was 2000, and the molar ratio of lactide to glycolide repeat units LA/GA was

Results and discussion

Fig. 1 displays the morphologies of the samples investigated with transmission electron microscopy (TEM, JEOL JEM-2100F). As shown in Fig. 1(a)–(c), porous nanospheres were formed in the presence of any of three PEG-based block copolymers. The average diameter of the porous nanospheres was less than 100 nm for all three samples. By contrast, if PEG was used instead of the block copolymer, only irregular nanoparticles were obtained, as shown in Fig. 1(d).

To investigate the composition of the

Conclusions

In summary, the calcium phosphate (CaP)/block copolymer hybrid porous nanospheres were synthesized by a simple solution method using CaCl2 and (NH4)2HPO4 in the presence of a block copolymer at room temperature. X-ray diffraction showed that calcium phosphate in the hybrid porous nanospheres was amorphous (ACP). The as-prepared CaP/PLLA-mPEG hybrid porous nanospheres were explored as drug carriers, and showed high ibuprofen loading capacity and in vitro prolonged drug release behavior in a

Acknowledgments

This work was financially supported by the Science and Technology Commission of Shanghai (1052 nm06200, 0852 nm05800), the National Natural Science Foundation of China (50772124, 50821004), and the Shanghai-Unilever Research and Development Fund (09520715200). We thank Professor Yourong Duan from the Cancer Institute of Shanghai Jiao Tong University for her kind provision of the block copolymers.

References (18)

  • M. Epple et al.

    J. Mater. Chem.

    (2010)
  • R.Z. Legeros

    Chem. Rev.

    (2008)
  • H.S. Muddana et al.

    Nano Lett.

    (2009)
  • M. Kester et al.

    Nano Lett.

    (2008)
  • T.T. Morgan et al.

    Nano Lett.

    (2008)
  • J. Schwiertz et al.

    Biomaterials

    (2009)
  • A. Bigi et al.

    Angew. Chem. Int. Ed.

    (2002)
  • A. Peytcheva et al.

    Colloid Poly Sci

    (2002)
  • M.Y. Ma et al.

    J. Mater. Chem.

    (2008)
There are more references available in the full text version of this article.

Cited by (25)

  • Targeted polymeric therapeutic nanoparticles: Design and interactions with hepatocellular carcinoma

    2015, Biomaterials
    Citation Excerpt :

    A t-test was used to detect differences between groups, and p < 0.05 was considered statistically significant in all evaluations. We synthesized three polymers, PDLA-CS (Supplementary Fig. 1) [13–15], PEG-PLGA-PLL (Supplementary Fig. 2) [6–8], and PEG-PS (Supplementary Fig. 3) [9–12]. Each of these polymers has hydrophilic and hydrophobic chains that allow them to easily self-assemble to form NPs.

  • Selective binding and magnetic separation of histidine-tagged proteins using Ni<sup>2+</sup>-decorated Fe<inf>3</inf>O<inf>4</inf>/hydroxyapatite composite nanoparticles

    2014, Materials Letters
    Citation Excerpt :

    These approaches, although promising, are often limited by complicated synthesis routes and time-consuming experiment techniques. Due to its favorable biocompatibility and adsorption capacity, HAP NPs have been studied for drug delivery, tissue engineering and protein adsorption [15,16]. Especially, HAP has rich surface active sites, and can immobilize metal ions through chelating bond.

  • Naturally and synthetic smart composite biomaterials for tissue regeneration

    2013, Advanced Drug Delivery Reviews
    Citation Excerpt :

    When the proteins were encapsulated within the inner PLGA part the release rate was further reduced. A delivery system of drugs within the CaP microspheres was also developed, where alendronate was in-situ loaded [163]. A sustainable release pattern of drug over 40 days was evident, and the release rate was controllable by modulation of the proportion of amorphous phase and the consequent degradation rate.

  • Peptide decorated calcium phosphate/carboxymethyl chitosan hybrid nanoparticles with improved drug delivery efficiency

    2013, International Journal of Pharmaceutics
    Citation Excerpt :

    For example, poly(ethylene glycol)-b-poly(aspartic acid) was used to control the crystallization of Ca–P and form a hybrid vector with improved gene transfection efficiency (Kakizawa et al., 2004). Tri-block and di-block copolymers containing poly(ethylene glycol) and polylactide segments could form hybrid nanoparticles with Ca–P with various sizes (Wang et al., 2010a,b). Carboxylmethyl cellulose was utilized to form hybrid particles with CaCO3 with controllable sizes (Peng et al., 2010; Zhao et al., 2007).

View all citing articles on Scopus
View full text