Curcumin-loaded biocompatible thermoresponsive polymeric nanoparticles for cancer drug delivery
Authors: N Sanoj Rejinold
H Tamura
P R Sreerekha
V V Divyarani
K P Chennazhi
S V Nair
M Muthunarayanan
R Jayakumar
Journal: Journal of Colloid and Interface Science (2011)
Discipline: CHEMISTRY
Keywords: curcumin; nanoparticles; drug delivery; thermoresponsive; chitosan
Affiliations: Amrita Centre for Nanosciences and Molecular Medicine, Amrita Institute of Medical Sciences and Research Centre, Amrita Vishwa Vidyapeetham University, Kochi, India.

Abstract:  This study aims at the formulation of curcumin with biodegradable thermoresponsive chitosan-g-poly (N-vinylcaprolactam) nanoparticles (TRC-NPs) for cancer drug delivery. The spherical curcumin-loaded nanoparticles of size 220 nm were characterized, and the biological properties were studied using flow cytometry and cytotoxicity by MTT assay. The in vitro drug release was higher at above LCST compared to that at below LCST. TRC-NPs in the concentration range of 100-1000 Œºg/mL were non-toxic to an array of cell lines. The cellular localization of the curcumin-loaded TRC-NPs was confirmed from green fluorescence inside the cells. The time-dependent curcumin uptake by the cells was quantified by UV spectrophotometer. Curcumin-loaded TRC-NPs showed specific toxicity to cancer cells at above their LCST. Flow cytometric analysis showed increased apoptosis on PC3 compared to L929 by curcumin-loaded TRC-NPs. These results indicate that novel curcumin-loaded TRC-NPs could be a promising candidate for cancer drug delivery. 

Retracted: No

PubPeer comments:
 Three papers of N. Sanoj Rejinold, published around the same time, appear to contain figures that look very similar to each other. Let s call them here papers A, B, and C. This post is on Paper B. * Paper A: Carbohydrate polymers 83, no. 2 (2011): 776-786. DOI: 10.1016 j.carbpol.2010.08.052 * Paper B: Journal of colloid and interface science 360, no. 1 (2011): 39-51. DOI: 10.1016 j.jcis.2011.04.006 * Paper C: International journal of biological macromolecules 49, no. 2 (2011): 161-172. DOI: 10.1016 j.ijbiomac.2011.04.008 Figure 5 of paper A, Figure 8 of paper B (this paper), and Figure 5 of paper C appear to show panels that look very similar across the three papers. Yet, each paper is based on a different nano-particle composite. Could the authors please explain?  , 
 Figure 7 of paper A, Figure 11 of paper B, and Figure 7 of paper C also share some similarities, in particular in the control panels. Could the authors please explain if they represent the same experiment?  , 
 Figure 3CD of paper A, Figure 5AB of paper B, and Figure 3FG of paper C also share some similarities. Even though each paper represents a different type of nanoparticle scaffold, the 2 graphs look remarkably similar across the papers. Could the authors please explain if they represent the same experiment?  , 
 Figure 2CD of paper A, Figure 3AB of paper B, and Figure 3AB of paper C also share some similarities. Some of the spectra represent the same compounds, but not in all cases. Could the authors please explain if they represent the same experiment?  , 
 Figure 2AB of paper A, Figure 4AB of paper B, and Figure 3CDE of paper C also share some similarities. The photos of the nanoparticles at different temperatures look very similar, as well as the temperature plots. Could the authors please explain if they represent the same experiment? Each of these 3 papers appears to look at a different type of nanoparticle.  , 
 Figure 14 of paper B and Figure 9 of paper C both show hemolysis experiments, but of different types of nanoparticles. Yet the photos look remarkably similar. Note the smudges of blood in the tube on the far right, and in the caps of some other tubes.  , 
 Figure 2 of paper B and Figure 2 of paper C also show remarkable similarities. The chemical structures are different but the photos appear to look the same. Could the authors please clarify?  , 
 Introducing paper D: * Paper A: Carbohydrate polymers 83, no. 2 (2011): 776-786. DOI: 10.1016 j.carbpol.2010.08.052 * Paper B: Journal of colloid and interface science 360, no. 1 (2011): 39-51. DOI: 10.1016 j.jcis.2011.04.006 * Paper C: International journal of biological macromolecules 49, no. 2 (2011): 161-172. DOI: 10.1016 j.ijbiomac.2011.04.008 * Paper D: ACS applied materials interfaces 3, no. 9 (2011): 3654-3665. DOI: 10.1021 am200844m Figure 10 of paper B, Figure 6 of paper C, and the first 4 bars of Figure 13 in paper D all appear to share unexpected similarities in relative heights and error bars.  , 
 In Figure 13 of this paper, some panels appear to look very similar. Panels in shades of blue might represent the same experiments, but the panels in pink and green appear to represent different experiments. In addition, the blue-shade panels look similar to panels in Figure 8 of paper C. Could the authors please comment?  , 
 I sent an email to 2 of this journalu2019s editors and the corresponding author. , 
 Corrigendum published [1 October 2019] . --------------------------- In the original manuscript, (Fig. 13A, B), the control L929 and PC3 plots were incorrect and also the control images given twice in the respective panel. Further, the L929-mitochondrial membrane potential (u0394u03a8m) values of bare TRC NPs and PC3-u0394u03a8m value for curcumin loaded TRC NPs (low) also cited wrong. This mistakes have been rectified and corrected Fig. 13 along with figure legend as represented below.  Additionally, in the original manuscript, the hemolysis photograph (Fig. 14) image is given incorrectly. This mistake has been rectified and the correct Fig. 14 along with figure legend is shown below.  These changes in the figures would not affect the conclusion from the figure nor the overall conclusion of the whole manuscript. The authors would like to apologise for any inconvenience caused. ,