Synthesis of mesoporous hydroxyapatite via a vitamin C templating hydrothermal route

doi:10.1016/j.matlet.2018.01.154

Materials Letters

Volume 218, 1 May 2018, Pages 52-55

https://doi.org/10.1016/j.matlet.2018.01.154 Get rights and content

Highlights

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Vitamin C is used to hydrothermally prepare mesoporous hydroxyapatite (HA).
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The pore size and morphology of HA were correlated to applied solution composition.
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The mesoporous HA has 88 m².g⁻¹ surface area and 15.7 nm pore size on average.

Abstract

Mesoporous hydroxyapatite is widely applied in biomedical and environmental fields due to its high surface area and adsorption capacity. In current work a one-step hydrothermal method to synthesize mesoporous HA was developed with the assistance of a cost-effective template vitamin C. It was observed the pore size and morphology of hydrothermally synthesized HA were correlated to applied solution composition. A combination of calcium hydroxide, orthophosphate, and vitamin C can finally result in mesoporous rod-like HA nanoparticles with surface area of 88 m².g⁻¹ and pore size of 15.7 nm on average. The mesoporous HA exhibited enhanced adsorption of model drug doxorubicin in comparison to conventionally synthesized HA as expected. Consequently, this work provides new pathway to prepare mesoporous HA with advantages of economy and convenience.

Introduction

Hydroxyapatite [HA, Ca₁₀₍PO₄)₆(OH)₂] is a well-studied material for both biomedical and environmental applications [1], [2]. With the development of nanotechnology, interests have been raised to prepare various inorganic nanostructures with tailored property and function [3], [4]. One typical attempt is to increase the surface area of nanomaterial via introducing mesoporous structure. Indeed, mesoporous HA has been proved to enhance protein adsorption capacity as well as stabilize protein release in comparison to conventional HA nanoparticles [5]. Besides, it can be used alone or combined with other water purification materials to remove toxic elements [6].

Templating method is the most well-known technique to synthesize mesoporous HA nanoparticles, in which a combination of hydrothermal precipitation and calcination process is applied to create desired HA using templates including Pluronic P123, Cetyltrimethylammonium Bromide (CTAB), Pluronic F127, and mono-alkyl phosphate (MAP), and casein [7], [8], [9]. On the other hand, physical attempts such as microwave, ultrasound treatments have been applied as well [10], [11]. However, these methods shown above are usually limited to a laboratory scale due to the cost or specific facility required. Synthesis of mesoporous HA with advantages of economy and convenience is still highly deserved to expand its applications.

As an alternative to previous attempts, in present work cost-effective vitamin C is used as a template to guide one-step hydrothermal formation of mesoporous HA. Besides, morphology/surface area regulation caused by the variation of chemical reactants were also investigated to search the recommended solution composition.

Section snippets

Materials and methods

All chemicals were purchased from Aladdin (Shanghai, China). Selected calcium and phosphate sources were added into 300 mL of distilled water, followed by addition of vitamin C. All compositions are summarized in Table 1. The prepared liquid mixture was magnetically stirred for 15 min with pH adjusted to 10 using 1 M NaOH solution. Subsequently, the suspension was hydrothermally treated in an autoclave of 121 °C for 4 h. The precipitates were centrifuged, washed with deionized water, and dried

Results and discussion

The XRD patterns of all samples are shown in Fig. 1a, displaying the characteristics of typical HA (PDF# 09-0432). This indicates that vitamin C has no effect of the phase purity of as synthesized HA. The crystal size and crystallinity of HA1 to HA5 are calculated to be 17.1 nm, 20.8 nm, 21.3 nm, 23.9 nm, 21.4 nm, and 72.58%, 74.88%, 80.05%, 80.37%, 80.45% respectively, suggesting that solution composition can definitely tailor the crystal growth of HA. The FTIR spectra exhibits typical

Conclusions

Mesoporous HA nanoparticles were one-step hydrothermally prepared using vitamin C as an additive. The impacts of different calcium sources, phosphate sources and vitamin C content on the morphology of formed HA were studied. It is wished this approach can simplify the manufacturing of the mesoporous HA for multiple applications.

Acknowledgements

This work was partially supported by Changzhou Sci & Tech Program (No. CJ20160040 and No. CE20152008), and Research Innovation Program for College Graduates of Jiangsu Province (No. SJCX17_0709).

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Synthesis of mesoporous hydroxyapatite via a vitamin C templating hydrothermal route

Highlights

Abstract

Introduction

Section snippets

Materials and methods

Results and discussion

Conclusions

Acknowledgements

Adv. Colloid Interface Sci

Colloids Surf. A Physicochem. Eng. Asp.

Mater. Sci. Eng. C-Mater. Biol. App.

Colloids Surf. A Physicochem. Eng. Asp

Ceram Int.

Colloid Surf. B-Biointerfaces