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Nanosized nickel oxide using bovine serum albumin as template
Materials Letters 58 (2004) 2914 – 2917 www.elsevier.com/locate/matlet
Nanosized nickel oxide using bovine serum albumin as template M. Kanthimathi, A. Dhathathreyan, B.U. Nair * Chemical Laboratory, Central Leather Research Institute, Adyar, Chennai-600 020, India Received 18 November 2003; accepted 6 May 2004 Available online 23 June 2004
Abstract Ultra fine, stable, high purity nickel oxide (NiO) with an average grain diameter of 13 – 14 nm has been synthesized by using bovine serum albumin (BSA) as a template under alkaline pH conditions and is characterized by thermo gravimetric analysis (TGA), X-ray diffraction (XRD) and transmission electron microscope (TEM) techniques. D 2004 Elsevier B.V. All rights reserved. Keywords: Nanocrystalline; NiO; BSA; Template
1. Introduction The control over particle size, shape and hence the dimensionality of nanoparticles is of great interest with respect to specific applications to materials such as nanodevices. The development of general pathways, therefore for the synthesis of quantum dots (zero dimensional), nanotubes, nanowires and nanorods, has become the main objective of nanochemistry [1]. Uniform particles whether atomic, molecular or colloidal in nature, organize to form ordered solids when attractive and repulsive interfacial forces are properly balanced [2]. Nanoscale oxide particulate materials are gaining increasing importance in the area of applications such as catalysts, passive electronic components and ceramic materials [3 – 6] which can not be achieved by their counterparts [7]. The synthesis of discrete magnetic nanoparticles with sizes ranging from 2 to 20 nm find applications in ferro-fluids, magnetic refrigeration systems, contrast enhancement in magnetic resonance imaging, magnetic carriers for drug targeting and as catalysts [8]. Several chemical methods reported for the preparation of metal oxide nanoparticles include, electro polymerization process [9] gas-phase method, sol – gel methods [10], chemical vapor deposition [11], and nanoscale bio mineralization
* Corresponding author. Fax: +91-44-24911589. E-mail address: [email protected] (B.U. Nair). 0167-577X/$ - see front matter D 2004 Elsevier B.V. All rights reserved. doi:10.1016/j.matlet.2004.05.026
[12]. In the synthesis of nanoparticles importance has been given to particle size distribution, size control, crystallinity, shape-control and the alignment of nanoparticles on substrate [13]. Biological systems control mineralization and nanocrystal synthesis of various metals in organisms [14]. An advantage in using biological systems to synthesize nanocrystals of metals is the efficiency and reproducibility in the production of uniform, pure and highly crystalline metal aggregates. Recently, defined sequences of peptides were used to mineralize specific metals to produce highly crystalline nanocrystals [15]. Djalali et al. [16] have reported a new biological approach to fabricate Au nanowires by using sequenced histidine-rich peptide nanowires as templates. Bio molecular surfaces such as tubules [17], bacterial fibres [18] and S-layer proteins [19] have also been used as structural templates to guide the deposition of inorganic materials within the pre determined spatial patterns. The formation of hollow shell architectures with tunable diameter has been reported [20]. As part of our work in the study of organization of proteins [21], DNA [22,23], coordinating with metal-ions, we have chosen bovine serum albumin (BSA), a self assembled protein, as template to prepare nanocrystalline metal oxides. In the scheme of metal binding to proteins, generally the hydrophilic protein residues tend to bind directly to metal through inner-sphere mechanism [24]. This method is based on the binding of transition metal salts to the protein because proteins are rich in binding
M. Kanthimathi et al. / Materials Letters 58 (2004) 2914–2917
Fig. 1. DTA-TGA curves of nickel hydroxide as synthesized in presence of BSA.
sites such as histidine, cystein, aspartic and glutamic acid residues. An interesting feature of this assembled structure is that a pair of amide groups should bind the neighboring dicarboxylate’s amide bonds via hydrogen bonds, while the other pair of amide groups are free to capture metal ions such as Pt, Pd, Cu and Ni, since these group of metals form a stable four coordinate planar structure as zwitterions with amino acid dimers [25]. We describe here for the first time a novel and facile method for the preparation of organized nanosized NiO using BSA as a template. BSA being a poly anion, in basic aqueous solution (ammonium hydroxide, pH 10.5), it forms selfaggregated template of supramolecular structures. The properties of the metal oxides were characterized by thermo gravimetric analysis (TGA), X-ray diffraction analysis (XRD) and transmission electron microscopy (TEM).
2. Experimental For the preparation of NiO, BSA was dissolved in distilled water (1 10 4 M) with stirring. A dilute solution (25% v/v) of ammonium hydroxide (10 ml) was then mixed with a solution of, NiCl26H2O (1 10 3M). To one part of this mixture, BSA solution was mixed and the other half was kept aside. Stirring was continued for 4 h, the slurry was aged for 2 days at room temperature to complete the immobilization of metal ions with BSA. On addition of aqueous metallic salts, the metal ions bind to BSA skeleton at the metal ion binding sites and subsequently due to higher pH conditions, they form corresponding metallic hydroxides. The reaction mixture was filtered, the precipitate washed repeatedly with water to remove any free metal salts as well as BSA. The precipitate was dried under ambient temperature to get a kind of light blue precursor, Ni(OH)2. 2(H2O), heated to 800 jC for 2 h in presence of air. The thermal decomposition of the precursor was studied using thermo gravimetric analysis (TGA) and differential thermal analysis
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(DTA) on a Dupont 2910 thermal analysis device. The determinations were carried out in air in an Al2O3 crucible at a heating rate of 10 jC/min in the temperature range of 25 – 800 jC. The calcined NiO thus obtained was subjected to XRD and TEM analyses and were found to be nanocrystalline in nature. The X-ray diffraction experiment were carried out using a linear position sensitive detector (Marconi Aironics). The ˚ ) was incident beam of Cu ka X-rays (wavelength 1.5418 A monochromatized using a pyrolytic graphite monochromator and a nickel filter. The samples were scanned from 20 to 70j (2h) in steps of 0.02j. The TEM experiments were carried out on Jeol-JEM 1200 EXII transmission electron microscope operated at 75 keV. TEM analysis on metal oxides prepared with and without using BSA template were also carried out by dispersing the powder samples in methanol and immersed in an ultrasonic bath for 30 min. A drop of this slurry was coated onto holey carbon copper TEM grid.
3. Results and discussion 3.1. Characterization of precursor In Fig. 1, the DTA and TGA thermo diagrams of the Ni(OH)22H2O before calcinations are shown. The DTA indicates a broad endothermic band at about 120 jC contributing to the dehydration of the sample. Another endothermic band in the range 450 –500 jC corresponds to decomposition of nickel hydroxide. There are two exothermic peaks at 630 and 680 jC which correspond to the oxidation of Ni to NiO. In TGA, major portion of weight loss seems to be 10% which is nearly coinciding with the theoretical weight loss of 8%. The difference results from contribution due to the absorption of protein. 3.2. Characteristics of the calcined nanocrystalline NiO Fig. 2 shows the wide angle-X-ray diffraction pattern of NiO sample with broad peaks at 2h values of 61.7, 45.5, 38.3 and 35.8j that correspond to crystal planes of (222),
Fig. 2. XRD pattern of NiO sample produced after heating at 800 jC in air for 2 h.
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M. Kanthimathi et al. / Materials Letters 58 (2004) 2914–2917
(220), (200) and (111). The crystal size (D) was calculated using Scherrer’s formula, D¼
k ðDW coshÞ
where D is the average particle size, k is the wavelength of X-ray, h is the Bragg’s diffraction angle and DW is the true half width of XRD lines. The value of true half width used to derive the average particle size lies between 0.8 and 0.6j. The broad peaks in the XRD pattern indicate that the samples consist of nanocrystalline domains with particle dimension of 13 nm for NiO. Fig. 3 shows representative selective area transmission electron microscopy (TEM) images recorded from methanol dispersed nanoparticles prepared by heating the precursor in presence of BSA at 800 jC. A number of nanoparticles are observed with the maximum length of 50 nm in case of NiO (Fig. 3a). Inset in (Fig. 3a) shows the corresponding diffraction rings indicating the crystalline net work of metal oxides produced. Selected regions in the TEM pictures showed fair amount of mono dispersity indicating most of the particles are fine, uniform with hexagonal shape. The magnified view of the particles are also shown in Fig. 3b. This shows that the calcined powder consists of solid hexagon like structures and measurable surface is not lost in inter particle contacts. A mean particle dimension estimated from XRD peaks (13 nm) agrees well with TEM observations (14.3 nm). A comparison of the XRD data with the electron diffraction (inset in Fig. 3a) shows, that in the TEM micrograph, only diffraction rings are seen and strong diffraction spots are not
recorded. These rings are characteristic of polycrystalline NiO. Although electron microscopy provides detailed information on selected areas of samples, it cannot address statistically large areas. The electron microscopy probes an area of about 100 nm in diameter. XRD probes both a superstructure as well as individual crystallites over a large volume of the sample. Hence more oriented crystals can be seen in the XRD patterns. In the present study, the sample in TEM shows that there are crystallites having isotropic distribution, oriented in many directions. This may arise due to the fast growth rates produced by the fast evaporation of the solvent during preparation of the sample for TEM. The TEM micrograph of the calcined NiO at 800 jC without BSA is shown in Fig. 3c. No uniform hexagonal crystalline particles are formed. Hence the protein, BSA plays major role in forming template in the build up of nanohexagonal particles of NiO. This methodology, in presence of BSA successfully overcomes the problem of agglomeration as in the conventional chemical precipitation method. Thus this work highlights the importance of BSA, as structural templates to guide the deposition of precursor within the pre determined spatial pattern which provides appropriate cavity wherein Ni(OH)2 particles are trapped in and grow on aging. Such an architecture is not possible in case of Ni(OH)2 powder formed in the absence of BSA. The NiO prepared using this present method gives much smaller particle with dimension of 13 nm when compared to NiO nanoparticles prepared with the surfactant mediated method (18.55 nm) as reported by Yu-de Wang et al. [5]. Particle formation is a very complex process. It involves complexation, nucleation and growth, all of which are mediated by BSA and pH conditions as in case of surfactant assemblies [26,27].
4. Conclusion Even though the use of TEM for determining the size of the particle is preferred over X-ray line broadening from the data shown above, it is observed that the crystallite dimensions estimated from half peak width using Scherrer’s formula and size of primary nanoparticles determined from imaging by TEM are agreeable within experimental error. Thus this present investigation describes a feasible synthesis of metal oxides in pure and small crystallites using proteins as templates. This finding proves that BSA mediated method could be a useful method for the preparation of pure nanocrystalline metal oxides.
Acknowledgements Fig. 3. TEM micrographs of NiO; (a) with BSA, figure in the inset is the corresponding selected-area diffraction patterns obtained on the image areas, (b) enlarged view of selected particles from (a), (c) without BSA.
The authors would like to thank Dr. Usha Ramamoorthy, Biophysics Department, CLRI for recording the TEM micrographs.
M. Kanthimathi et al. / Materials Letters 58 (2004) 2914–2917
References [1] M. Niederberger, M.H. Barti, G.D. Stucky, J. Am. Chem. Soc. 124 (2002) 13642; G.J. Li, X.X. Huang, Y. Shi, J.K. Guo, Mater. Lett. 51 (2001) 325; R.E. Cavicchi, R.H. Silsbe, Phys. Rev. Lett. 52 (16) (1984) 1453; P. Ball, G. Li, Nature 355 (1992) 761. [2] C.B. Murray, C.R. Kagan, M.G. Bawendi, Science 270 (1995) 1335. [3] A.P. Alivisato, K.P. Johnson, X. Peng, T.F. Wilson, C.J. Loweth, M.P. Bruchez, P.G. Schultz, Nature 382 (1996) 609. [4] A.P. Alivisato, Science 271 (1996) 933. [5] Yu-de Wang, C. Lai ma, X. Dan Sun, H. Li, Inorg. Chem. Commun. 5 (2002) 751. [6] C. Feldmann, H.O. Jungk, Angew. Chem., Int. Ed. 40 (2000) 359. [7] A.J. Zazur, J.Y. Ying, Nature 403 (2000) 65. [8] B.M. Berkovsky, V.F. Medvedev, M.S. Krakov, Magnetic Fluids: Engineering Applications, Oxford University press, Oxford, 1993. [9] K. Hata, H. Fujihara, J. Chem. Soc., Chem. Commun. (2002) 2714. [10] S.R. Whaley, D.S. English, E.L. Hu, P.F. Barbara, A.M. Belcher, Nature 6787 (2000) 665; K.T. Lee, S.M. Oh, J. Chem. Soc., Chem. Commun. (2002) 2722. [11] D. Shigehito, K. Akamatsu, T. Yano, M. Mizuhata, A. Kajunami, J. Mater. Chem. 818 (1998) 1865; J. Geng, C. Sing, D.S. Shephard, M.S.P. Shaffer, B.F.G. Johnson, A.H. Windle, J. Chem. Soc., Chem. Commun. (2002) 2666; H. Dai, Phys. World (2000) 43. [12] M. Kogiso, K. Yoshida, K. Yase, T. Shimizu, J. Chem. Soc., Chem. Commun. (2002) 2492. [13] T. Hyeon, Chem. Commun. (2003) 927.
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[14] S. Brown, M. Sarikaya, E. Johnson, J. Mol. Biol. 299 (2000) 725. [15] J. Ziegler, R.T. Chang, D.W. Wright, J. Am. Chem Soc. 121 (1999) 2395. [16] R. Djalali, Y. Chen, H. Matsui, J. Am. Chem. Soc. 124 (2002) 13660. [17] D.D. Archibald, S. Mann, Nature 364 (1993) 430. [18] N.H. Mendelsen, Science 258 (1992) 1633. [19] K. Douglas, N.A. Clark, K. Rothschils, J. Appl. Phys. Lett. 56 (1990) 692. [20] J.J.L.M. Cornelissen, E.F. Connor, H. Cheol Kim, V.Y. Lee, T. Magbitgang, P.M. Rice, W. Volksen, L.K. Sundberg, R.D. Miller, Chem. Commun. (2003) 1010. [21] M. Kanthimathi, R. Maheswari, A. Dhathathreyan, Langmuir 19 (2003) 3398. [22] R. Vijayalakshmi, M. Kanthimathi, V. Subramanian, B.U. Nair, Biochem. Biophys. Res. Commun. 271 (2000) 731; R. Vijayalakshmi, A. Dhathathreyan, M. Kanthimathi, V. Subramanian, B.U. Nair, T. Ramasami, Langmuir 15 (1999) 2898. [23] R. Vijayalakshmi, M. Kanthimathi, V. Subramanian, B.U. Nair, Biochim. Biophys. Acta 1475 (2000) 157. [24] T.C. Dudev, J. Lim, J. Phys. Chem., B 104 (2000) 3692. [25] K. Nakamoto, Infrared and Raman Spectra of Inorganic and Coordination Compounds, vol. 1, John Wiley and Sons, New York, 1997, part B. [26] G.M. Chow, K.E. Gonsalves, in: A.S. Edelstein, R.C. Cammarata (Eds.), Nanomaterials: Synthesis, Properties and Applications, Institute of Physics Publishing, Bristol, 1996, p. 65. [27] S.G. Dixit, A.R. Mahadeshwar, S.K. Haram, ‘‘Colloids Surf. A: Physico chem. Eng. Aspects’’, 1998, 133, p.69. Abstract/PDF (319 K).
Nanosized nickel oxide using bovine serum albumin as template M. Kanthimathi, A. Dhathathreyan, B.U. Nair * Chemical Laboratory, Central Leather Research Institute, Adyar, Chennai-600 020, India Received 18 November 2003; accepted 6 May 2004 Available online 23 June 2004
Abstract Ultra fine, stable, high purity nickel oxide (NiO) with an average grain diameter of 13 – 14 nm has been synthesized by using bovine serum albumin (BSA) as a template under alkaline pH conditions and is characterized by thermo gravimetric analysis (TGA), X-ray diffraction (XRD) and transmission electron microscope (TEM) techniques. D 2004 Elsevier B.V. All rights reserved. Keywords: Nanocrystalline; NiO; BSA; Template
1. Introduction The control over particle size, shape and hence the dimensionality of nanoparticles is of great interest with respect to specific applications to materials such as nanodevices. The development of general pathways, therefore for the synthesis of quantum dots (zero dimensional), nanotubes, nanowires and nanorods, has become the main objective of nanochemistry [1]. Uniform particles whether atomic, molecular or colloidal in nature, organize to form ordered solids when attractive and repulsive interfacial forces are properly balanced [2]. Nanoscale oxide particulate materials are gaining increasing importance in the area of applications such as catalysts, passive electronic components and ceramic materials [3 – 6] which can not be achieved by their counterparts [7]. The synthesis of discrete magnetic nanoparticles with sizes ranging from 2 to 20 nm find applications in ferro-fluids, magnetic refrigeration systems, contrast enhancement in magnetic resonance imaging, magnetic carriers for drug targeting and as catalysts [8]. Several chemical methods reported for the preparation of metal oxide nanoparticles include, electro polymerization process [9] gas-phase method, sol – gel methods [10], chemical vapor deposition [11], and nanoscale bio mineralization
* Corresponding author. Fax: +91-44-24911589. E-mail address: [email protected] (B.U. Nair). 0167-577X/$ - see front matter D 2004 Elsevier B.V. All rights reserved. doi:10.1016/j.matlet.2004.05.026
[12]. In the synthesis of nanoparticles importance has been given to particle size distribution, size control, crystallinity, shape-control and the alignment of nanoparticles on substrate [13]. Biological systems control mineralization and nanocrystal synthesis of various metals in organisms [14]. An advantage in using biological systems to synthesize nanocrystals of metals is the efficiency and reproducibility in the production of uniform, pure and highly crystalline metal aggregates. Recently, defined sequences of peptides were used to mineralize specific metals to produce highly crystalline nanocrystals [15]. Djalali et al. [16] have reported a new biological approach to fabricate Au nanowires by using sequenced histidine-rich peptide nanowires as templates. Bio molecular surfaces such as tubules [17], bacterial fibres [18] and S-layer proteins [19] have also been used as structural templates to guide the deposition of inorganic materials within the pre determined spatial patterns. The formation of hollow shell architectures with tunable diameter has been reported [20]. As part of our work in the study of organization of proteins [21], DNA [22,23], coordinating with metal-ions, we have chosen bovine serum albumin (BSA), a self assembled protein, as template to prepare nanocrystalline metal oxides. In the scheme of metal binding to proteins, generally the hydrophilic protein residues tend to bind directly to metal through inner-sphere mechanism [24]. This method is based on the binding of transition metal salts to the protein because proteins are rich in binding
M. Kanthimathi et al. / Materials Letters 58 (2004) 2914–2917
Fig. 1. DTA-TGA curves of nickel hydroxide as synthesized in presence of BSA.
sites such as histidine, cystein, aspartic and glutamic acid residues. An interesting feature of this assembled structure is that a pair of amide groups should bind the neighboring dicarboxylate’s amide bonds via hydrogen bonds, while the other pair of amide groups are free to capture metal ions such as Pt, Pd, Cu and Ni, since these group of metals form a stable four coordinate planar structure as zwitterions with amino acid dimers [25]. We describe here for the first time a novel and facile method for the preparation of organized nanosized NiO using BSA as a template. BSA being a poly anion, in basic aqueous solution (ammonium hydroxide, pH 10.5), it forms selfaggregated template of supramolecular structures. The properties of the metal oxides were characterized by thermo gravimetric analysis (TGA), X-ray diffraction analysis (XRD) and transmission electron microscopy (TEM).
2. Experimental For the preparation of NiO, BSA was dissolved in distilled water (1 10 4 M) with stirring. A dilute solution (25% v/v) of ammonium hydroxide (10 ml) was then mixed with a solution of, NiCl26H2O (1 10 3M). To one part of this mixture, BSA solution was mixed and the other half was kept aside. Stirring was continued for 4 h, the slurry was aged for 2 days at room temperature to complete the immobilization of metal ions with BSA. On addition of aqueous metallic salts, the metal ions bind to BSA skeleton at the metal ion binding sites and subsequently due to higher pH conditions, they form corresponding metallic hydroxides. The reaction mixture was filtered, the precipitate washed repeatedly with water to remove any free metal salts as well as BSA. The precipitate was dried under ambient temperature to get a kind of light blue precursor, Ni(OH)2. 2(H2O), heated to 800 jC for 2 h in presence of air. The thermal decomposition of the precursor was studied using thermo gravimetric analysis (TGA) and differential thermal analysis
2915
(DTA) on a Dupont 2910 thermal analysis device. The determinations were carried out in air in an Al2O3 crucible at a heating rate of 10 jC/min in the temperature range of 25 – 800 jC. The calcined NiO thus obtained was subjected to XRD and TEM analyses and were found to be nanocrystalline in nature. The X-ray diffraction experiment were carried out using a linear position sensitive detector (Marconi Aironics). The ˚ ) was incident beam of Cu ka X-rays (wavelength 1.5418 A monochromatized using a pyrolytic graphite monochromator and a nickel filter. The samples were scanned from 20 to 70j (2h) in steps of 0.02j. The TEM experiments were carried out on Jeol-JEM 1200 EXII transmission electron microscope operated at 75 keV. TEM analysis on metal oxides prepared with and without using BSA template were also carried out by dispersing the powder samples in methanol and immersed in an ultrasonic bath for 30 min. A drop of this slurry was coated onto holey carbon copper TEM grid.
3. Results and discussion 3.1. Characterization of precursor In Fig. 1, the DTA and TGA thermo diagrams of the Ni(OH)22H2O before calcinations are shown. The DTA indicates a broad endothermic band at about 120 jC contributing to the dehydration of the sample. Another endothermic band in the range 450 –500 jC corresponds to decomposition of nickel hydroxide. There are two exothermic peaks at 630 and 680 jC which correspond to the oxidation of Ni to NiO. In TGA, major portion of weight loss seems to be 10% which is nearly coinciding with the theoretical weight loss of 8%. The difference results from contribution due to the absorption of protein. 3.2. Characteristics of the calcined nanocrystalline NiO Fig. 2 shows the wide angle-X-ray diffraction pattern of NiO sample with broad peaks at 2h values of 61.7, 45.5, 38.3 and 35.8j that correspond to crystal planes of (222),
Fig. 2. XRD pattern of NiO sample produced after heating at 800 jC in air for 2 h.
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M. Kanthimathi et al. / Materials Letters 58 (2004) 2914–2917
(220), (200) and (111). The crystal size (D) was calculated using Scherrer’s formula, D¼
k ðDW coshÞ
where D is the average particle size, k is the wavelength of X-ray, h is the Bragg’s diffraction angle and DW is the true half width of XRD lines. The value of true half width used to derive the average particle size lies between 0.8 and 0.6j. The broad peaks in the XRD pattern indicate that the samples consist of nanocrystalline domains with particle dimension of 13 nm for NiO. Fig. 3 shows representative selective area transmission electron microscopy (TEM) images recorded from methanol dispersed nanoparticles prepared by heating the precursor in presence of BSA at 800 jC. A number of nanoparticles are observed with the maximum length of 50 nm in case of NiO (Fig. 3a). Inset in (Fig. 3a) shows the corresponding diffraction rings indicating the crystalline net work of metal oxides produced. Selected regions in the TEM pictures showed fair amount of mono dispersity indicating most of the particles are fine, uniform with hexagonal shape. The magnified view of the particles are also shown in Fig. 3b. This shows that the calcined powder consists of solid hexagon like structures and measurable surface is not lost in inter particle contacts. A mean particle dimension estimated from XRD peaks (13 nm) agrees well with TEM observations (14.3 nm). A comparison of the XRD data with the electron diffraction (inset in Fig. 3a) shows, that in the TEM micrograph, only diffraction rings are seen and strong diffraction spots are not
recorded. These rings are characteristic of polycrystalline NiO. Although electron microscopy provides detailed information on selected areas of samples, it cannot address statistically large areas. The electron microscopy probes an area of about 100 nm in diameter. XRD probes both a superstructure as well as individual crystallites over a large volume of the sample. Hence more oriented crystals can be seen in the XRD patterns. In the present study, the sample in TEM shows that there are crystallites having isotropic distribution, oriented in many directions. This may arise due to the fast growth rates produced by the fast evaporation of the solvent during preparation of the sample for TEM. The TEM micrograph of the calcined NiO at 800 jC without BSA is shown in Fig. 3c. No uniform hexagonal crystalline particles are formed. Hence the protein, BSA plays major role in forming template in the build up of nanohexagonal particles of NiO. This methodology, in presence of BSA successfully overcomes the problem of agglomeration as in the conventional chemical precipitation method. Thus this work highlights the importance of BSA, as structural templates to guide the deposition of precursor within the pre determined spatial pattern which provides appropriate cavity wherein Ni(OH)2 particles are trapped in and grow on aging. Such an architecture is not possible in case of Ni(OH)2 powder formed in the absence of BSA. The NiO prepared using this present method gives much smaller particle with dimension of 13 nm when compared to NiO nanoparticles prepared with the surfactant mediated method (18.55 nm) as reported by Yu-de Wang et al. [5]. Particle formation is a very complex process. It involves complexation, nucleation and growth, all of which are mediated by BSA and pH conditions as in case of surfactant assemblies [26,27].
4. Conclusion Even though the use of TEM for determining the size of the particle is preferred over X-ray line broadening from the data shown above, it is observed that the crystallite dimensions estimated from half peak width using Scherrer’s formula and size of primary nanoparticles determined from imaging by TEM are agreeable within experimental error. Thus this present investigation describes a feasible synthesis of metal oxides in pure and small crystallites using proteins as templates. This finding proves that BSA mediated method could be a useful method for the preparation of pure nanocrystalline metal oxides.
Acknowledgements Fig. 3. TEM micrographs of NiO; (a) with BSA, figure in the inset is the corresponding selected-area diffraction patterns obtained on the image areas, (b) enlarged view of selected particles from (a), (c) without BSA.
The authors would like to thank Dr. Usha Ramamoorthy, Biophysics Department, CLRI for recording the TEM micrographs.
M. Kanthimathi et al. / Materials Letters 58 (2004) 2914–2917
References [1] M. Niederberger, M.H. Barti, G.D. Stucky, J. Am. Chem. Soc. 124 (2002) 13642; G.J. Li, X.X. Huang, Y. Shi, J.K. Guo, Mater. Lett. 51 (2001) 325; R.E. Cavicchi, R.H. Silsbe, Phys. Rev. Lett. 52 (16) (1984) 1453; P. Ball, G. Li, Nature 355 (1992) 761. [2] C.B. Murray, C.R. Kagan, M.G. Bawendi, Science 270 (1995) 1335. [3] A.P. Alivisato, K.P. Johnson, X. Peng, T.F. Wilson, C.J. Loweth, M.P. Bruchez, P.G. Schultz, Nature 382 (1996) 609. [4] A.P. Alivisato, Science 271 (1996) 933. [5] Yu-de Wang, C. Lai ma, X. Dan Sun, H. Li, Inorg. Chem. Commun. 5 (2002) 751. [6] C. Feldmann, H.O. Jungk, Angew. Chem., Int. Ed. 40 (2000) 359. [7] A.J. Zazur, J.Y. Ying, Nature 403 (2000) 65. [8] B.M. Berkovsky, V.F. Medvedev, M.S. Krakov, Magnetic Fluids: Engineering Applications, Oxford University press, Oxford, 1993. [9] K. Hata, H. Fujihara, J. Chem. Soc., Chem. Commun. (2002) 2714. [10] S.R. Whaley, D.S. English, E.L. Hu, P.F. Barbara, A.M. Belcher, Nature 6787 (2000) 665; K.T. Lee, S.M. Oh, J. Chem. Soc., Chem. Commun. (2002) 2722. [11] D. Shigehito, K. Akamatsu, T. Yano, M. Mizuhata, A. Kajunami, J. Mater. Chem. 818 (1998) 1865; J. Geng, C. Sing, D.S. Shephard, M.S.P. Shaffer, B.F.G. Johnson, A.H. Windle, J. Chem. Soc., Chem. Commun. (2002) 2666; H. Dai, Phys. World (2000) 43. [12] M. Kogiso, K. Yoshida, K. Yase, T. Shimizu, J. Chem. Soc., Chem. Commun. (2002) 2492. [13] T. Hyeon, Chem. Commun. (2003) 927.
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[14] S. Brown, M. Sarikaya, E. Johnson, J. Mol. Biol. 299 (2000) 725. [15] J. Ziegler, R.T. Chang, D.W. Wright, J. Am. Chem Soc. 121 (1999) 2395. [16] R. Djalali, Y. Chen, H. Matsui, J. Am. Chem. Soc. 124 (2002) 13660. [17] D.D. Archibald, S. Mann, Nature 364 (1993) 430. [18] N.H. Mendelsen, Science 258 (1992) 1633. [19] K. Douglas, N.A. Clark, K. Rothschils, J. Appl. Phys. Lett. 56 (1990) 692. [20] J.J.L.M. Cornelissen, E.F. Connor, H. Cheol Kim, V.Y. Lee, T. Magbitgang, P.M. Rice, W. Volksen, L.K. Sundberg, R.D. Miller, Chem. Commun. (2003) 1010. [21] M. Kanthimathi, R. Maheswari, A. Dhathathreyan, Langmuir 19 (2003) 3398. [22] R. Vijayalakshmi, M. Kanthimathi, V. Subramanian, B.U. Nair, Biochem. Biophys. Res. Commun. 271 (2000) 731; R. Vijayalakshmi, A. Dhathathreyan, M. Kanthimathi, V. Subramanian, B.U. Nair, T. Ramasami, Langmuir 15 (1999) 2898. [23] R. Vijayalakshmi, M. Kanthimathi, V. Subramanian, B.U. Nair, Biochim. Biophys. Acta 1475 (2000) 157. [24] T.C. Dudev, J. Lim, J. Phys. Chem., B 104 (2000) 3692. [25] K. Nakamoto, Infrared and Raman Spectra of Inorganic and Coordination Compounds, vol. 1, John Wiley and Sons, New York, 1997, part B. [26] G.M. Chow, K.E. Gonsalves, in: A.S. Edelstein, R.C. Cammarata (Eds.), Nanomaterials: Synthesis, Properties and Applications, Institute of Physics Publishing, Bristol, 1996, p. 65. [27] S.G. Dixit, A.R. Mahadeshwar, S.K. Haram, ‘‘Colloids Surf. A: Physico chem. Eng. Aspects’’, 1998, 133, p.69. Abstract/PDF (319 K).