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Poly( o-methoxyaniline) Chain Degradation Based on a Heat Treatment (HT) Process: Combined Experimental and Theoretical Evaluation. Molecules 2022; 27:molecules27123693. [PMID: 35744819 PMCID: PMC9231141 DOI: 10.3390/molecules27123693] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Revised: 06/03/2022] [Accepted: 06/06/2022] [Indexed: 11/17/2022] Open
Abstract
Poly(o-methoxyaniline) emeraldine-salt form (ES-POMA) was chemically synthesized using hydrochloric acid and subjected to a heat treatment (HT) process for 1 h at 100 °C (TT100) and 200 °C (TT200). The HT process promoted a progressive decrease in crystallinity. The Le Bail method revealed a decomposition from tetrameric to trimeric-folded chains after the HT process. The unheated POMA-ES presented a globular vesicular morphology with varied micrometric sizes. The heat treatment promoted a reduction in these globular structures, increasing the non-crystalline phase. The boundary length (S) and connectivity/Euler feature (χ) parameters were calculated from the SEM images, revealing that ES-POMA presented a wide distribution of heights. The TT100 and TT200 presented a narrow boundary distribution, suggesting smoother surfaces with smaller height variations. The UV-VIS analysis revealed that the transition at 343 nm (nonlocal π → π*) was more intense in the TT200 due to the electronic delocalization, which resulted from the reduced polymer chain caused by the HT process. In addition to the loss of conjugation, counter ion withdrawal reduced the ion-chain interaction, decreasing the local electron density. This result shows the influence of the chlorine counter ions on the peaks position related to the HOMO → LUMO transition, since the π → polaron transition occurs due to the creation of the energy states due to the presence of counter ions. Finally, the electrical conductivity decreased after the HT process from 1.4 × 10−4 S.cm−1 to 2.4 × 10−6 S.cm−1 as result of the polymer deprotonation/degradation. Thus, this paper proposed a systematic evaluation of the POMA molecular structure and crystallite size and shape after heat treatment.
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Maity N, Dawn A. Conducting Polymer Grafting: Recent and Key Developments. Polymers (Basel) 2020; 12:E709. [PMID: 32210062 PMCID: PMC7182814 DOI: 10.3390/polym12030709] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Revised: 03/17/2020] [Accepted: 03/20/2020] [Indexed: 12/13/2022] Open
Abstract
Since the discovery of conductive polyacetylene, conductive electroactive polymers are at the focal point of technology generation and biocommunication materials. The reasons why this research never stops growing, are twofold: first, the demands from the advanced technology towards more sophistication, precision, durability, processability and cost-effectiveness; and second, the shaping of conducting polymer research in accordance with the above demand. One of the major challenges in conducting polymer research is addressing the processability issue without sacrificing the electroactive properties. Therefore, new synthetic designs and use of post-modification techniques become crucial than ever. This quest is not only advancing the field but also giving birth of new hybrid materials integrating merits of multiple functional motifs. The present review article is an attempt to discuss the recent progress in conducting polymer grafting, which is not entirely new, but relatively lesser developed area for this class of polymers to fine-tune their physicochemical properties. Apart from conventional covalent grafting techniques, non-covalent approach, which is relatively new but has worth creation potential, will also be discussed. The aim is to bring together novel molecular designs and strategies to stimulate the existing conducting polymer synthesis methodologies in order to enrich its fascinating chemistry dedicated toward real-life applications.
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Affiliation(s)
- Nabasmita Maity
- Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem 91904, Israel;
| | - Arnab Dawn
- James Winkle College of Pharmacy, University of Cincinnati, Cincinnati, OH 45267-514, USA
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de Oliveira LR, Manzato L, Mascarenhas YP, Sanches EA. The influence of heat treatment on the semi-crystalline structure of polyaniline Emeraldine-salt form. J Mol Struct 2017. [DOI: 10.1016/j.molstruc.2016.09.044] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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da Silva J, de Souza S, Trovati G, Sanches E. Chloride salt of conducting polyaniline synthesized in the presence of CeO2: Structural analysis of the core-shell nanocomposite. J Mol Struct 2017. [DOI: 10.1016/j.molstruc.2016.07.114] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Nandi S, Mukherjee P, Kundu A, Nandi AK. Nanojacketing and Dejacketing of ds-DNA: A Nondestructive Characterization of a Nanojacketed Sample by Impedance Spectroscopy. J Phys Chem B 2014; 118:2649-61. [DOI: 10.1021/jp412373m] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Sudipta Nandi
- Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032, India
| | - Pratap Mukherjee
- Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032, India
| | - Aniruddha Kundu
- Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032, India
| | - Arun K. Nandi
- Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032, India
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Sanches E, Soares J, Mafud A, Trovati G, Fernandes E, Mascarenhas Y. Structural and morphological characterization of chloride salt of conducting poly(o-methoxyaniline) obtained at different time synthesis. J Mol Struct 2013. [DOI: 10.1016/j.molstruc.2012.12.025] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Sanches E, Soares J, Mafud A, Fernandes E, Leite F, Mascarenhas Y. Structural characterization of Chloride Salt of conducting polyaniline obtained by XRD, SAXD, SAXS and SEM. J Mol Struct 2013. [DOI: 10.1016/j.molstruc.2012.09.084] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Pereira NS, do Monte AFG, Ceschin AM, Sales MJA. POMA/PMMA blends modified by dye: Spectroscopic and morphological properties. J Appl Polym Sci 2013. [DOI: 10.1002/app.37869] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Nandi S, Routh P, Layek RK, Nandi AK. Ethidium Bromide-Adsorbed Graphene Templates as a Platform for Preferential Sensing of DNA. Biomacromolecules 2012; 13:3181-8. [DOI: 10.1021/bm3009632] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Sudipta Nandi
- Indian Association for the Cultivation of Science, Jadavpur, Kolkata-700 032, India
| | - Parimal Routh
- Indian Association for the Cultivation of Science, Jadavpur, Kolkata-700 032, India
| | - Rama K. Layek
- Indian Association for the Cultivation of Science, Jadavpur, Kolkata-700 032, India
| | - Arun K. Nandi
- Indian Association for the Cultivation of Science, Jadavpur, Kolkata-700 032, India
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Routh P, Garai A, Nandi AK. Optical and electronic properties of polyaniline sulfonic acid–ribonucleic acid–gold nanobiocomposites. Phys Chem Chem Phys 2011; 13:13670-82. [DOI: 10.1039/c1cp20365g] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Mukherjee P, Dawn A, Nandi AK. Biomolecular hybrid of poly(3-thiophene acetic acid) and double stranded DNA: optical and conductivity properties. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2010; 26:11025-11034. [PMID: 20499876 DOI: 10.1021/la101215v] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
A new biomolecular hybrid of poly(3-thiophene acetic acid) (PTAA) and double stranded deoxyribonucleic acid (ds-DNA) is prepared. The transmission electron microscopy (TEM) images exhibit fibrillar network morphology making a nanostructured self-assembly of PTAA-DNA hybrid. The confocal fluorescence image of PTAA shows green fluorescence exhibiting agglomeration in the pure state but the spreading of green fluorescence over the network superstructure in the hybrids indicating the immobilization of PTAA on DNA surfaces. Fourier transform infrared (FTIR) spectra indicate hydrogen bonding between -COOH groups of PTAA and P=O groups of Na-DNA. Circular dichroism (CD) spectra denote that DNA conformation remains unaltered during hybrid preparation. A blue shift of the pi-pi* absorption peak of PTAA in the hybrid solutions occurs with aging time. The photoluminescence intensity in the hybrid solution increases with a concomitant blue shift of the emission peak with aging time, and it is faster with increased DNA concentration. Possible reasons of different optical behavior are discussed in the light of duplex and triplex hybrid formation. Dynamic light scattering study indicates an increased particle size of PTAA with addition of DNA favoring the hybrid particles to remain in solution. The dc-conductivity of the hybrids decreases from that of PTAA with an increase of Na-DNA concentration, and the current (I)-voltage (V) curves indicate a semiconducting nature of the hybrids.
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Affiliation(s)
- Pratap Mukherjee
- Polymer Science Unit, Indian Association for the Cultivation of Science, Jadavpur, Kolkata-700 032, India
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Shi J, Chen Y, Wang Q, Liu Y. Construction and efficient radical cation stabilization of cyclodextrin/aniline polypseudorotaxane and its conjugate with carbon nanotubes. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2010; 22:2575-2578. [PMID: 20440700 DOI: 10.1002/adma.200904333] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Affiliation(s)
- Jun Shi
- Department of Chemistry, State Key Laboratory of Elemento-Organic Chemistry, Nankai University, Tianjin 300071, P.R. China
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Routh P, Mukherjee P, Nandi AK. RNA-poly(o-methoxyaniline) hybrid templated growth of silver nanoparticles and nanojacketing: physical and electronic properties. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2010; 26:5093-5100. [PMID: 20020756 DOI: 10.1021/la903553t] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Three nanobiocomposites (PRAg31, PRAg11, and PRAg13; the numbers indicate the weight ratios of poly(o-methoxyaniline) (POMA) and ribonucleic acid (RNA), respectively), produced from the same amount of POMA (P) and silver nitrate (AgNO(3)) with differing proportions of RNA (R) are prepared by aging the aqueous solutions of the mixture for 3 weeks at 30 degrees C. The scanning and transmission electron microscopy (SEM and TEM) indicate Ag nanoparticle formation on the hybrid fiber surface and in the PRAg31 system the hybrid fibrils become coated with metallic Ag, the phenomenon being termed as "nanojacketting". The circular dichroism (CD) spectra indicate a small distortion of RNA conformation from A helix toward B helix. FTIR and UV-vis spectra suggest that POMA (emeraldine base, EB) being doped by Ag(+) become oxidized to its pernigraniline base (PB) form and reduce Ag(+) to metallic Ag. The Ag nanoparticles thus produced become stabilized on the fibril surface by co-ordination through nitrogen atoms of POMA (PB) chains. The much slower red shift of pi band to polaron band transition peak in PRAg31 than that of the other two nanobiocomposites is indicative of difficulty in conformational transitions of POMA chain in the "nanojacketted" hybrid fibrils. The dc-conductivity values of the nanobiocomposites are two orders higher than that of the pure POMA-RNA hybrids. The PRAg31 system exhibits rectification property in the I-V characteristic curves and a probable explanation based on the feasibility of p-n junction formation arising from the transfer of lone pair of electrons of nitrogen of POMA (p-type) to the Ag nanoparticles (n-type) has been offered.
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Affiliation(s)
- Parimal Routh
- Polymer Science Unit, Indian Association for the Cultivation of Science, Jadavpur, Kolkata-700 032, India
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Anilkumar P, Jayakannan M. Large-scale synthesis of polyaniline nanofibers based on renewable resource molecular template. J Appl Polym Sci 2009. [DOI: 10.1002/app.30962] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Li K, Wang N, Yang F, Zhang ZW, Zhou LH, Chen SY, Lin HH, Tian YF, Yu XQ. Cyclen-based side-chain homopolymer self-assembly with plasmid DNA: protection of DNA from enzymatic degradation. Chem Biodivers 2009; 6:754-63. [PMID: 19479841 DOI: 10.1002/cbdv.200800080] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
In this study, a 1,4,7,10-tetraazacyclododecane (cyclen)-based side-chain homopolymer was developed for the first time; this polymer can self-assembly with plasmid DNA to form polyelectrolyte complexes (polyplex), which can protect DNA from enzymatic degradation. Moreover, the polyplex can disassembly and release free DNA when NaCl solution is added to this system. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) are used for imaging of the surface structure of the polyplex, and results indicated that the polyplex structures respond to the polymer concentration. Circular dichroism (CD) spectrum suggested that the DNA configuration in the polyplex was retained.
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Affiliation(s)
- Kun Li
- Department of Chemistry, Key Laboratory of Green Chemistry and Technology (Ministry of Education), Sichuan University, Chengdu, P. R. China
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Routh P, Mukherjee P, Dawn A, Nandi AK. Self assembly of poly(o-methoxy aniline) with RNA and RNA/DNA hybrids: physical properties and conformational change of poly(o-methoxy aniline). Biophys Chem 2009; 143:145-53. [PMID: 19482408 DOI: 10.1016/j.bpc.2009.05.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2009] [Revised: 05/08/2009] [Accepted: 05/13/2009] [Indexed: 11/25/2022]
Abstract
Biomolecular hybrids of a conducting polymer [poly(o-methoxy aniline) (POMA)] and RNA are prepared at the three different compositions by mixing aqueous solutions of diethyl, 2-hydroxy ethyl, ammonium salt of RNA (type IX from Torula Yeast) and POMA (ES, emeraldine salt; doping level [Cl]/[N]=0.52). A slow increase of pH up to 30 h of aging occurs in the mixture till it levels up. The TEM micrographs indicate a fibrillar network structure in all the hybrid compositions (POMA: RNA=1:3, 1:1, 3:1, by weight). In the complexes three types of supramolecular interactions, viz. (i) electrostatic, (ii) H-bonding and (iii) pi-pi interactions, are evident from the FTIR spectroscopy. The CD spectra indicate a small distortion of A-RNA conformation towards its B form during the hybrid formation. Time and temperature dependent UV-vis spectral studies indicate a slow red shift of the pi-band to polaron band transition peak (lambda(max)) for the uncoiling of the POMA (P) chain on the RNA (R) surface. The repulsive interaction between the radical cations of POMA (ES) absorbed on the RNA surface is attributed to the conformational change causing the uncoiling of POMA chain. UV-vis spectral study indicates that the uncoiling and attachment of POMA on RNA surface is much faster than that on DNA (D). In POMA-RNA-DNA (PRD) hybrid solutions slower red shift of lambda(max) indicates more disordered array of the phosphate groups than that in PR and PD systems. The conductivity values of the PR hybrids (10(-)(6) S/cm(-1)) are three orders higher than that of RNA, rendering the PR hybrids to be useful for fabricating good biosensors. In the PRD hybrids conductivity decreases by two orders than those of PR and PD hybrids suggesting a disorder arrangement of POMA chains in the PRD hybrids. The I-V characteristic curves of the PR and PRD hybrids indicate a semiconducting nature of the hybrids.
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Affiliation(s)
- Parimal Routh
- Polymer Science Unit, Indian Association for the Cultivation of Science, Jadavpur, Kolkata, India
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Nie G, Zhang Y, Xu J, Zhang S. Low-potential facile electrosyntheses of free-standing poly(5-methoxyindole) film with good fluorescence properties. J Electroanal Chem (Lausanne) 2008. [DOI: 10.1016/j.jelechem.2008.05.008] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Liu Y, Shi J, Chen Y, Ke CF. A Polymeric Pseudorotaxane Constructed from Cucurbituril and Aniline, and Stabilization of Its Radical Cation. Angew Chem Int Ed Engl 2008. [DOI: 10.1002/ange.200802805] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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A Polymeric Pseudorotaxane Constructed from Cucurbituril and Aniline, and Stabilization of Its Radical Cation. Angew Chem Int Ed Engl 2008; 47:7293-6. [DOI: 10.1002/anie.200802805] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Redox and ion-exchange properties in surface-tethered DNA-conducting polymers. Biosens Bioelectron 2008; 23:1171-4. [DOI: 10.1016/j.bios.2007.10.016] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2007] [Revised: 10/01/2007] [Accepted: 10/23/2007] [Indexed: 11/19/2022]
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Saha A, Manna S, Nandi AK. A mechanistic approach on the self-organization of the two-component thermoreversible hydrogel of riboflavin and melamine. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2007; 23:13126-13135. [PMID: 18001072 DOI: 10.1021/la7026219] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
The riboflavin (R) and melamine (M) supramolecular complex in the mole ratio of 3:1 (RM31) produces a thermoreversible gel in aqueous medium. The gelation mechanism has been elucidated from morphological investigations using optical, electron, and atomic force microscopy together with time-dependent circular dichroism (CD) and photoluminescence (PL) spectroscopy. Optical microscopy indicates spherulitic morphology at lower gelation temperature (<or=25 degrees C), but at higher temperature fibrillar network morphology develops. Electron and atomic force microscopy indicate the presence of left handed helical structures in the fibrils. Kinetic study of gel formation using circular dichroism (CD) and photoluminescence (PL) spectra indicates that there are three steps: (1) RM complex formation, (2) conformational ordering, and (3) pi-pi-stacking of ordered conformers. The first step of RM complex formation is already established from Fourier transform infrared (FTIR) spectroscopy (Manna, S.; Saha, A.; Nandi, A. K. Chem. Commun. 2006, 4285), and the second step is detected from the CD spectra. Here, the ellipticity value of the n-pi* transition increases by 600 times during gel formation. The dramatic increase of ellipticity is attributed to conformational ordering of the ribityl chain followed by helical fibril formation. The third step is concluded from fluorescence spectroscopy, which also shows a 30 times increase in intensity. The substantial increase in PL intensity is caused by hydrophobic core formation during pi-stacking of the complex. Both the ellipticity and PL intensity show a sigmoidal increase with time, and analysis of data using the Avrami equation shows n values close to 1.5 for the former and close to 2 for the latter. The rate constant values obtained from the intercepts of Avrami plots are different in the two methods. The rate constant data from the CD spectra show a small positive temperature coefficient, but the rate constant values from the PL data show a negative temperature coefficient except the data at 30 and 35 degrees C. Arrhenius treatment of the rate constant values of the CD data indicates an activation energy of approximately 13 kcal/mol, signifying that the conformational transition is the cause of ellipticity increase. The negative temperature coefficient of the rate constant obtained from the fluorescence data has been attributed to the spherulitic crystal formation, and the increase of the rate constant at 30 and 35 degrees C has been attributed to fibril formation. The fluorescence intensity and peak position change with temperature and with the concentration of the RM complex in the gel. A probable explanation from fibrillar thickness is offered.
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Affiliation(s)
- Abhijit Saha
- Polymer Science Unit, Indian Association for the Cultivation of Science, Jadavpur, Kolkata-700 032, India
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Tan WL, Qin W, Yung LYL. Difference in “Base Pair to Termini” Affects the Enzymatic Digestion of Nanoparticle-Bonded DNA. Biomacromolecules 2007; 8:750-2. [PMID: 17291101 DOI: 10.1021/bm060904y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Wei Ling Tan
- Department of Chemical and Biomolecular Engineering, National University of Singapore, 10 Kent Ridge Crescent, Singapore 119260, Singapore
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Baron R, Willner B, Willner I. Biomolecule–nanoparticle hybrids as functional units for nanobiotechnology. Chem Commun (Camb) 2007:323-32. [PMID: 17220964 DOI: 10.1039/b610721b] [Citation(s) in RCA: 149] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Biomolecule-metal or semiconductor nanoparticle (NP) hybrid systems combine the recognition and catalytic properties of biomolecules with the unique electronic and optical properties of NPs. This enables the application of the hybrid systems in developing new electronic and optical biosensors, to synthesize nanowires and nanocircuits, and to fabricate new devices. Metal NPs are employed as nano-connectors that activate redox enzymes, and they act as electrical or optical labels for biorecognition events. Similarly, semiconductor NPs act as optical probes for biorecognition processes. Double-stranded DNA or protein chains that are modified with metallic nanoclusters act as templates for the synthesis of metallic nanowires. The nanowires are used as building blocks to assemble nano-devices such as a transistor or a nanotransporter.
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Affiliation(s)
- Ronan Baron
- Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem, 91904, Israel
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Dawn A, Nandi AK. Formation of Silver Nanoparticles in Deoxyribonucleic Acid−Poly(o-methoxyaniline) Hybrid: A Novel Nano-biocomposite. J Phys Chem B 2006; 110:18291-8. [PMID: 16970449 DOI: 10.1021/jp063269z] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A novel nano-biocomposite of silver and poly(o-methoxy aniline) (POMA)/DNA hybrid has been prepared by adding DNA solution to an aqueous solution of POMA (emeraldine base, EB) and AgNO(3) mixture. The mixture was aged for 10 days and was freeze-dried to form the hybrid nanocomposite (weight fraction of DNA = 0.75). FESEM pictures show a fibrillar network morphology of the biomolecular hybrid with silver nanoparticles on its surface. The TEM picture also corroborates silver nanoparticle formation in the biomolecular hybrid, and the denser population of nanoparticles in the TEM micrograph as compared to that in the SEM micrograph indicates that the nanoparticles are present inside the fibrils in greater proportion. The dc conductivity value of the hybrid indicates that POMA (EB) is doped by silver ion and the doped POMA form complexes 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 pi band to polaron band transition peak occurs together with a complementary fluctuation of the polaron band to pi* band transition peak. After 53 h of aging, the former shows a slow but continuous red shift with aging time. This has been attributed to the slow uncoiling of POMA on the DNA surface. The conformation and crystal structure of DNA remain intact during the nano-biocomposite formation. The dc conductivity value of 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 region on low applied voltage. At higher applied voltage, it shows a semiconducting property characterizing the large band gap semiconducting behavior of the nano-biocomposite.
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Affiliation(s)
- Arnab Dawn
- Polymer Science Unit, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032, India
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