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RETRACTED ARTICLE: Surface-functionalized gold nanoparticles mediate bacterial transformation: a nanobiotechnological approach

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This article was retracted on 19 April 2015


Transformation of bacteria is an important step in molecular biology. Viral and non-virus-based gene delivery techniques, including chemical/biological and physical approaches, have been applied to bacterial, mammalian and plant cells. E. coli is not competent to take up DNA; hence, different methods are used to incorporate plasmid DNA. A novel method has been developed using glutathione-functionalized gold nanoparticles to mediate transformation of plasmid DNA (pUC19) into E. coli DH5α that does not require the preparation of competent cells. The glutathione-functionalized gold nanoparticles acted as a vector and facilitated the entry of DNA into the host cell. The method also gave a higher transformation efficiency (4.2 × 107/μg DNA) compared to 2.3 × 105/μg DNA using the conventional CaCl2-mediated method. It was also non-toxic to the bacterium making it suitable for biotechnological applications.

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This research work has been carried out with the financial support of Department of Science & Technology, Government of India (Project-Nanomission: SR/NM/NS-48/2009) and University of Kalyani, Nadia, West Bengal.

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Correspondence to Keka Sarkar.

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A paper by Saptarshi Chatterjee and Keka Sarkar that was published in this journal is now retracted due to the deliberate and fraudulent use of data in the paper that had previously appeared in other papers of these two authors and in other papers of Dr Sarkar.

The paper in question is: “Surface-functionalized gold nanoparticles mediate bacterial transformation; a nanobiotechnological approach”; Biotechnology Letters 2014 36:265-271, by S Chatterjee and K Sarkar.

In this paper, the authors used previously published data from other publications of theirs: Chatterjee, Bandyopadhyay and Sarkar “Effect of iron oxide and gold nanoparticles on bacterial growth leading towards biological application” in Journal of Nanobiotechnology 2011 9:34

Two figures in the paper in Biotechnology Letters had been taken from this paper: Figure 2c was identical to Figure 3 in the J Nanobiotech paper and Figure 4 (inset) was identical to Figure 7 (left). No acknowledgement was given that these figures were identical. In addition, the two figures illustrated results from apparently different experiments.

In addition, Figure 2c in the Biotech Letters paper was identical to a figure (Figure 1) in another publication of Dr Sarkar and colleagues: “Bacterial growth response on interaction with iron oxide and gold nanoparticles: Measuring risk to the environment” IEEE 2011 (International Conference on Nanoscience, Technology and Societal Implications; doi 10.1109/NSTSI.2011.6111986) pages 1-6. Figure 2b in the IEEE publication was also repeated in the Biotechnology Letters paper (Figure 4) without any acknowledgement of prior publication. Figure 2a in the Biotechnology Letters paper was also used without modification in another publication of this group: “Localized surface plasmon resonance-based DNA detection in solution using gold-decorated supraparamagnetic Fe3O4 nanocomposite”; Bandyopadhyay and Sarkar in Analytical Biochemistry 2014 465:156-163.

As we have been made aware of other duplications of data in other papers of Dr Sarkar, and also the use of other people’s data and figures as deliberate acts of plagiarism, we have come to the conclusion that this person has knowingly and deliberately used the same data and figures to illustrate results from different scientific experiments in her various publications. Therefore the veracity of the work in the paper of Chatterjee and Sarkar that was published in this journal, and indeed in other journals that have been published in the last five years, cannot be vouchsafed and must be regarded as fraudulent or potentially fraudulent. The paper in Biotechnology Letters is therefore retracted.

An inquiry into Dr Sarkar’s publications has been conducted by her university (University of Kalyani, West Bengal, India) and has resulted in a severe reprimand and restrictions concerning her future in the university.

Colin Ratledge, Editor in Chief

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Chatterjee, S., Sarkar, K. RETRACTED ARTICLE: Surface-functionalized gold nanoparticles mediate bacterial transformation: a nanobiotechnological approach. Biotechnol Lett 36, 265–271 (2014).

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