Electrophoretically prepared hybrid materials for biopolymer hydrogel and layered ceramic nanoparticles
© Gwak et al. 2016
Received: 9 September 2015
Accepted: 4 January 2016
Published: 10 February 2016
In order to obtain biomaterials with controllable physicochemical properties, hybrid biomaterials composed of biocompatible biopolymers and ceramic nanoparticles have attracted interests. In this study, we prepared biopolymer/ceramic hybrids consisting of various natural biopolymers and layered double hydroxide (LDH) ceramic nanoparticles via an electrophoretic method. We studied the structures and controlled-release properties of these materials.
Results and discussion
X-ray diffraction (XRD) patterns and X-ray absorption spectra (XAS) showed that LDH nanoparticles were formed in a biopolymer hydrogel through electrophoretic reaction. Scanning electron microscopic (SEM) images showed that the ceramic nanoparticles were homogeneously distributed throughout the hydrogel matrix. An antioxidant agent (i.e., ferulic acid) was loaded onto agarose/LDH and gelatin/LDH hybrids, and the time-dependent release of ferulic acid was investigated via high-performance liquid chromatography (HPLC) for kinetic model fitting.
Biopolymer/LDH hybrid materials that were prepared by electrophoretic method created a homogeneous composite of two components and possessed controllable drug release properties according to the type of biopolymer.
KeywordsBiopolymer Agarose Gelatin Ceramic Layered double hydroxide Electrophoretic synthesis Controlled release
Biomaterials, in a broad sense of the definition, are materials that can be applied to biological systems. They include materials used in medical devices, artificial tissues/organs, bone cement, dental implants, biosensors, catheters, drug delivery systems, hygiene items, etc. [1–3]. In terms of their material properties, biomaterials can be classified as polymers, metals, ceramics, and hybrid materials. Among them, polymers (e.g., poly(lactic acid) (PLA), poly(glycolic acid) (PGA), and poly(lactic-co-glycolic acid) (PLGA)) have been widely studied for soft tissue applications to recover the structure and function of organs. Polymers are desirable because they possess mechanical flexibility, biodegradability, cellular interaction, easy modification, etc. [4, 5]. Natural polymers, like collagen, have been investigated for use as tissue engineering scaffolds . Ceramics are often utilized in hard tissue applications because they have high mechanical strength and chemical stability. For instance, calcium phosphate and hydroxyapatites have been extensively studied for use in mesenchymal stem cell differentiation, bone engineering, and dental implants [7–9]. Metallic biomaterials, such as stainless steel, Ti alloys, and Co-Cr alloys, can be applied in surgical implants or bone tissue engineering applications due to their easy sterilization, high mechanical strength, fracture resistance, and widely available fabrication techniques [10, 11].
Recently, hybrid biomaterials consisting of two or more components have been developed in order to achieve synergic effects. For instance, polymer/polymer hybrids of gelatin, alginate, hyaluronate, and chitosan were reported as wound dressings; these materials have controlled porosity and water uptake properties . An agarose/chitosan hybrid that was suggested by Z. Cao et al. achieved reasonable mechanical strength and effective neuronal growth in 3D space . C. Du et al. reported a hydroxyapatite-incorporated collagen-ceramic/polymer hybrid that was both bioactive and biodegradable . Y. Ito et al. developed hybrids that were composed of biocompatible and biodegradable poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) nanofibers and hydroxyapatite in order to achieve high specific surface area, surface hydrophilicity, and enzyme invasion .
Herein, we demonstrate possible biopolymer/LDH hybrids made via an electrophoretic method. The obtained hybrids were analyzed in terms of their structure and nanoparticle distribution utilizing X-ray diffraction, X-ray absorption spectroscopy, and electron microscopy. We also investigated the potential of these prepared hybrids in sustained drug release system utilizing an antioxidant agent, ferulic acid, as the model drug.
Agarose (MW: 120 kDa) was purchased from Bio Basic Inc., Canada. Gelatin (from porcine skin), zinc nitrate hexahydrate (Zn(NO3)2 · 6H2O), aluminum nitrate nonahydrate (Al(NO3)3 · 9H2O), sodium bicarbonate (NaHCO3), tris(hydroxymethyl)aminomethane (Tris: NH2C(CH2OH)3), and the antioxidant agent (ferulic acid (C10H10O4)) were purchased from Sigma-Aldrich Co. LLC, USA. Ammonia water (NH4OH), sodium hydroxide (NaOH), and hydrochloric acid (HCl) were purchased from Daejung Chemicals & Metals Co. LTD., Korea.
In order to prepare biopolymer/LDH hybrid materials electrophoretically, a home-made electrophoretic kit was utilized. First, the biopolymer powder (1 wt/v% for agarose and 2 wt/v% for gelatin and the other biopolymers) was dissolved in tris-HCl buffer (pH 7.4) at 120 oC. Then, the solution was poured into the center of the electrophoretic kit walled by plastic plates and cooled down to room temperature for 4 h to obtain a cuboidal hydrogel. The cationic metal solution (0.16 M Zn2+ and 0.08 M Al3+) and the anionic solution (0.08 M NaHCO3 and 1 mL NH4OH), which were precursors for LDH, were located at each side of the cuboidal hydrogel. Then, electrophoresis was operated with 25 V for 30 min. After reaction, the hydrogel was washed with deionized water and thoroughly dehydrated.
As a reference sample for LDH, ZnAl-CO3-LDH (Zn2Al(OH)6(CO3)0.5) was prepared by conventional coprecipitation method, as reported elsewhere . Typically, the cationic metal solution (0.063 M Zn2+ and 0.0315 M Al3+) was titrated with basic solution (NaOH and NaHCO3) to pH ~8.5 with vigorous stirring. After 24 h, white precipitates formed. These were centrifuged, washed by deionized water, and then dried.
Prepared hybrids were characterized by X-ray diffraction (XRD), X-ray absorption spectroscopy (XAS), and field emission scanning electron microscope (FE-SEM). In order to identify the crystal structure of the ceramic particles in the hybrid, XRD patterns and XAS spectra were obtained by Bruker D2 phaser with Ni-filtered Cu-Kα radiation (λ = 1.5406 Å) and at the 7D XAFS beam line at the Pohang Accelerator Laboratory (Pohang, Korea), respectively. FE-SEM images, obtained with Hitachi SU-70 at the Korea Basic Science Institute (Gangneung Center, Korea), showed the shape and size of LDH nanoparticles in the hybrids.
Sustained release test
(Qt: release amount at time t, t: time, α and β: Elovich constants representing the initial release rate and the overall release rate, respectively.)
Results and discussion
Hydrogel candidates for the electrophoretic preparation method
Cuboidal hydrogel formation
Electrophoretic hybrid formation
○ (with divalent cations)
○ (with divalent cations)
We prepared polymer/ceramic hybrid biomaterials via an electrophoretic preparation method. These materials are suitable for the homogeneous formation of ceramic nanoparticles in a hydrogel. We chose agarose and gelatin as the polymer component and LDH nanoparticles as the ceramic component. All of these materials have adequate biocompatibility and are widely applied in biomedical fields. We identified the crystal structure of LDH nanoparticles by XRD and XAS, which showed that the ceramic nanoparticles inside of the hybrid had the desired LDH structure. By analyzing SEM images, LDH nanoparticles were determined to be homogeneously formed in the hydrogel as we expected. Ferulic acid (the drug model molecule used in our study) was well-loaded onto the biopolymer/LDH hybrid and was released in a sustained manner.
This work was supported by a grant from the Postharvest Research Project (PJ010502) of RDA, Republic of Korea.
Open AccessThis article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.
- Tathe A, Ghodke M, Nikalje AP. A brief review: biomaterials and their application. Int J Pharm Pharm Sci. 2010;2:19–23.Google Scholar
- Patel NR, Gohil PP. A review on biomaterials: scope, applications & human anatomy significance. Int J Emerging Technol Adv Eng. 2012;2:91–101.Google Scholar
- Lee HB. Needs and opportunities for the biomaterials industry. Polym Sci Technol. 1994;5:566–76.Google Scholar
- Griffith L. Polymeric biomaterials. Acta Mater. 2000;48:263–77.View ArticleGoogle Scholar
- Petzetakis N, Dove AP, O’Reilly RK. Cylindrical micelles from the living crystallization-driven self-assembly of poly (lactide)-containing block copolymers. Chem Sci. 2011;2:955–60.View ArticleGoogle Scholar
- Hayashi T. Biodegradable polymers for biomedical uses. Prog Polym Sci. 1994;19:663–702.View ArticleGoogle Scholar
- Phadke A, Zhang C, Hwang Y, Vecchio K, Varghese S. Templated mineralization of synthetic hydrogels for bone-like composite materials: Role of matrix hydrophobicity. Biomacromolecules. 2010;11:2060–8.View ArticleGoogle Scholar
- Shih Y-RV, Hwang Y, Phadke A, Kang H, Hwang NS, Caro EJ, et al. Calcium phosphate-bearing matrices induce osteogenic differentiation of stem cells through adenosine signaling. Proc Natl Acad Sci. 2014;111:990–5.View ArticleGoogle Scholar
- Holmes RE. Bone regeneration within a coralline hydroxyapatite implant. Plast Reconstr Surg. 1979;63:626–33.View ArticleGoogle Scholar
- Staiger MP, Pietak AM, Huadmai J, Dias G. Magnesium and its alloys as orthopedic biomaterials: a review. Biomaterials. 2006;27:1728–34.View ArticleGoogle Scholar
- Narayan R. Biomedical materials, Springer Science & Business Media. 2009. pp. 41–81.
- Choi YS, Lee S, Hong SR, Lee Y, Song K, Park M. Studies on gelatin-based sponges. Part III: a comparative study of cross-linked gelatin/alginate, gelatin/hyaluronate and chitosan/hyaluronate sponges and their application as a wound dressing in full-thickness skin defect of rat. J Mater Sci Mater Med. 2001;12:67–73.View ArticleGoogle Scholar
- Cao Z, Gilbert RJ, He W. Simple Agarose-Chitosan Gel Composite System for Enhanced Neuronal Growth in Three Dimensions. Biomacromolecules. 2009;10:2954–9.View ArticleGoogle Scholar
- Du C, Cui F, Feng Q, Zhu X, de Groot K. Tissue response to nano-hydroxyapatite/collagen composite implants in marrow cavity. J Biomed Mater Res. 1998;42:540–8.View ArticleGoogle Scholar
- Ito Y, Hasuda H, Kamitakahara M, Ohtsuki C, Tanihara M, Kang I-K, et al. A composite of hydroxyapatite with electrospun biodegradable nanofibers as a tissue engineering material. J Biosci Bioeng. 2005;100:43–9.View ArticleGoogle Scholar
- Gwak GH, Paek SM, Oh JM. Electrophoretic Preparation of an Organic–Inorganic Hybrid of Layered Metal Hydroxide and Hydrogel for a Potential Drug‐Delivery System. Eur J Inorg Chem. 2012;2012:5269–75.View ArticleGoogle Scholar
- Alaminos M, Sánchez-Quevedo MDC, Munoz-Ávila JI, Serrano D, Medialdea S, Carreras I, et al. Construction of a complete rabbit cornea substitute using a fibrin-agarose scaffold. Invest Ophthalmol Vis Sci. 2006;47:3311–7.View ArticleGoogle Scholar
- Mauck RL, Soltz MA, Wang CC, Wong DD, Chao P-HG, Valhmu WB, et al. Functional tissue engineering of articular cartilage through dynamic loading of chondrocyte-seeded agarose gels. J Biomech Eng. 2000;122:252–60.View ArticleGoogle Scholar
- Campo VL, Kawano DF, da Silva DB, Carvalho I. Carrageenans: Biological properties, chemical modifications and structural analysis–A review. Carbohydr Polym. 2009;77:167–80.View ArticleGoogle Scholar
- Edwards C, Blackburn N, Craigen L, Davison P, Tomlin J, Sugden K, et al. Viscosity of food gums determined in vitro related to their hypoglycemic actions. Am J Clin Nutr. 1987;46:72–7.Google Scholar
- Wang L, Shelton R, Cooper P, Lawson M, Triffitt J, Barralet J. Evaluation of sodium alginate for bone marrow cell tissue engineering. Biomaterials. 2003;24:3475–81.View ArticleGoogle Scholar
- Tasneem M, Siddique F, Ahmad A, Farooq U. Stabilizers: Indispensable substances in dairy products of high rheology. Crit Rev Food Sci Nutr. 2014;54:869–79.View ArticleGoogle Scholar
- Oh EJ, Park K, Kim KS, Kim J, Yang J-A, Kong J-H, et al. Target specific and long-acting delivery of protein, peptide, and nucleotide therapeutics using hyaluronic acid derivatives. J Control Release. 2010;141:2–12.View ArticleGoogle Scholar
- Cavani F, Trifirò F, Vaccari A. Hydrotalcite-type anionic clays: Preparation, properties and applications. Catal Today. 1991;11:173–301.View ArticleGoogle Scholar
- Choy J-H, Jung J-S, Oh J-M, Park M, Jeong J, Kang Y-K, et al. Layered double hydroxide as an efficient drug reservoir for folate derivatives. Biomaterials. 2004;25:3059–64.View ArticleGoogle Scholar
- Khan AI, Lei L, Norquist AJ, O’Hare D. Intercalation and controlled release of pharmaceutically active compounds from a layered double hydroxide. Chem Commun. 2001;2001:2342–3.View ArticleGoogle Scholar
- Foord S, Atkins E. New x‐ray diffraction results from agarose: Extended single helix structures and implications for gelation mechanism. Biopolymers. 1989;28:1345–65.View ArticleGoogle Scholar
- Ki CS, Baek DH, Gang KD, Lee KH, Um IC, Park YH. Characterization of gelatin nanofiber prepared from gelatin–formic acid solution. Polymer. 2005;46:5094–102.View ArticleGoogle Scholar
- Woo MA, Song M-S, Kim TW, Kim IY, Ju J-Y, Lee YS, et al. Mixed valence Zn–Co-layered double hydroxides and their exfoliated nanosheets with electrode functionality. J Mater Chem. 2011;21:4286–92.View ArticleGoogle Scholar
- Hennig C, Hallmeier K-H, Zahn G, Tschwatschal F, Hennig H. Conformational influence of dithiocarbazinic acid bishydrazone ligands on the structure of zinc (II) complexes: a comparative XANES study. Inorg Chem. 1999;38:38–43.View ArticleGoogle Scholar
- Choy J-H, Kwon Y-M, Han K-S, Song S-W, Chang SH. Intra-and inter-layer structures of layered hydroxy double salts, Ni1− x Zn2x(OH)2(CH3CO2)2x · nH2O. Mater Lett. 1998;34:356–63.View ArticleGoogle Scholar
- Li Y, Rodrigues J, Tomas H. Injectable and biodegradable hydrogels: gelation, biodegradation and biomedical applications. Chem Soc Rev. 2012;41:2193–221.View ArticleGoogle Scholar
- Oh J-M, Biswick TT, Choy J-H. Layered nanomaterials for green materials. J Mater Chem. 2009;19:2553–63.View ArticleGoogle Scholar
- Lima E, Flores J, Cruz AS, Leyva-Gómez G, Krötzsch E. Controlled release of ferulic acid from a hybrid hydrotalcite and its application as an antioxidant for human fibroblasts. Microporous Mesoporous Mat. 2013;181:1–7.View ArticleGoogle Scholar
- Chein S, Clayton W. Application of Elovich equation to the kinetics of phosphate release and sorption in soil. J Am Soil Sci Soc. 1980;44:265–8.View ArticleGoogle Scholar
- Yang J-H, Han Y-S, Park M, Park T, Hwang S-J, Choy J-H. New inorganic-based drug delivery system of indole-3-acetic acid-layered metal hydroxide nanohybrids with controlled release rate. Chem Mater. 2007;19:2679–85.View ArticleGoogle Scholar