Formation of Silver Nanoparticles in Deoxyribonucleic Acid-Poly(o-methoxyaniline) Hybrid: A Novel Nano-biocomposite
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- 作者：Arnab Dawn ; Arun K. Nandi
- 刊名：Journal of Physical Chemistry B
- 出版年：2006
- 出版时间：September 21, 2006
- 年：2006
- 卷：110
- 期：37
- 页码：18291 - 18298
- 全文大小：520K
- 年卷期：v.110,no.37(September 21, 2006)
- ISSN：1520-5207
文摘
A novel nano-biocomposite of silver and poly(o-methoxy aniline) (POMA)/DNA hybrid has been preparedby adding DNA solution to an aqueous solution of POMA (emeraldine base, EB) and AgNO3 mixture. Themixture was aged for 10 days and was freeze-dried to form the hybrid nanocomposite (weight fraction ofDNA = 0.75). FESEM pictures show a fibrillar network morphology of the biomolecular hybrid with silvernanoparticles on its surface. The TEM picture also corroborates silver nanoparticle formation in the biomolecularhybrid, and the denser population of nanoparticles in the TEM micrograph as compared to that in the SEMmicrograph indicates that the nanoparticles are present inside the fibrils in greater proportion. The dcconductivity value of the hybrid indicates that POMA (EB) is doped by silver ion and the doped POMA formcomplexes with DNA through electrostatic interaction of the radical cation of POMA (emeraldine salt form,ES) and the DNA anion. During the doping process and Ag nanoparticle formation, a fluctuation of the 
band to polaron band transition peak occurs together with a complementary fluctuation of the polaron bandto * band transition peak. After 53 h of aging, the former shows a slow but continuous red shift with agingtime. This has been attributed to the slow uncoiling of POMA on the DNA surface. The conformation andcrystal structure of DNA remain intact during the nano-biocomposite formation. The dc conductivity valueof the nano-biocomposite is almost the same as that of the pure POMA-DNA hybrid at the same composition,but the I-V characteristic curve of the nano-biocomposite is somewhat different showing an insulating regionon low applied voltage. At higher applied voltage, it shows a semiconducting property characterizing thelarge band gap semiconducting behavior of the nano-biocomposite.
band to polaron band transition peak occurs together with a complementary fluctuation of the polaron bandto * band transition peak. After 53 h of aging, the former shows a slow but continuous red shift with agingtime. This has been attributed to the slow uncoiling of POMA on the DNA surface. The conformation andcrystal structure of DNA remain intact during the nano-biocomposite formation. The dc conductivity valueof the nano-biocomposite is almost the same as that of the pure POMA-DNA hybrid at the same composition,but the I-V characteristic curve of the nano-biocomposite is somewhat different showing an insulating regionon low applied voltage. At higher applied voltage, it shows a semiconducting property characterizing thelarge band gap semiconducting behavior of the nano-biocomposite.