Correction: PEGylated gold nanoparticles: polymer quantification as a function of PEG lengths and nanoparticle dimensions

Abstract

Correction for ‘PEGylated gold nanoparticles: polymer quantification as a function of PEG lengths and nanoparticle dimensions’ by Kamil Rahme et al., RSC Adv., 2013, 3, 6085–6094.

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The authors regret that the surface area calculation of the grafting density was originally calculated using πr² instead of 4πr². This error does not affect the overall conclusions of this paper. Furthermore, the correct surface area was used in the calculation of the polymer conformation. The corrected grafting densities and foot prints have been included below.

In the abstract, the decrease in grafting density of the mPEG-SH ligands should read “0.983 to 0.07 PEG per nm²” and the decrease in grafting density of the mPEG_10 000-SH should read “0.393 to 0.2 PEG per nm²”.

The data in Table 2 should read:

Table 2. Surface coverage (from TGA) and mPEG-SH layer thickness (from DLS size distribution by volume) on 15 nm gold nanoparticles

mPEG-SH (Mw)	Number of EO	DLS (v)/PEG layer (nm)	Weight loss (%) T > 320 °C	NPEG per 15 nm AuNP	Foot print (nm^2)	Grafting density per nm^2
2100	47	2.83 ± 0.66	6.7	695 ± 87	1.02	0.983
5400	122	7.79 ± 1.0	9.9	424 ± 53	1.67	0.6
10 800	245	12.77 ± 1.5	12	278 ± 42	2.54	0.393
19 500	443	21.61 ± 2.5	10.82	132 ± 16.5	5.35	0.187
29 500	670	25.6 ± 3.0	10	81 ± 10	8.77	0.114
51 400	1168	37.15 ± 4.0	10.85	50 ± 6	14.2	0.07

The data in Table 3 should read:

Table 3. Surface coverage (from TGA) of different AuNPs diameter (EM/DLS) coated with mPEG_10 000-SH

Diameter (nm)/EM	Diameter (nm)/DLS (I)	Weight loss (%) T > 320 °C	NPEG/AuNP	Foot print (nm^2)	Grafting density per nm^2
15 ± 1.8	59 ± 3.5	14.25	278 ± 42	2.54	0.393
30 ± 3.5	72 ± 5	5.7	916 ± 106	3.12	0.323
62.5 ± 6	102 ± 9	1.64	2572 ± 402	5	0.2
93 ± 12	138 ± 10	1.41	6778 ± 814	4.2	0.24
115 ± 10	165 ± 14	1.449	12 960 ± 1227	3.2	0.312

Fig. 5 should be replaced by the following figure:

The text also affects the discussion of Fig. 5 on page 6091 which should read:

“Specifically, the number of PEG molecules grafted to the Au nanoparticles decreased by ∼12 fold from 695 ± 87 for mPEG₂₀₀₀-SH (0.983 PEG per nm²) to 50 ± 6 for mPEG_48 500-SH (0.07 PEG per nm²). The solid line is an exponential fit to the data. Increased conformational entropy of the PEG molecules with polymer chain length leads to an increase in the footprint of the PEG molecules at the Au nanoparticle surface from 1.02 nm² for mPEG₂₀₀₀-SH to 14.2 nm² for mPEG_48 500-SH (see Table 2)

The text discussing mPEG_10 000-SH on the same page also requires amendment:

Finally, some similar behaviour has been observed in this work where the grafting density of mPEG_10 000-SH was higher on 15 nm diameter Au nanoparticles and decreased slightly from 0.393 to 0.2 PEG per nm² when the particle size increased to 65 nm in diameter (Table 3).”

The last three lines on page 3 of the ESI should read:

“So from this experiment we estimate that 15 nm AuNPs contain 278 PEG_10 000-SH. The grafting density correspond to 278/706.84 ∼ 0.393 PEG_10 000 per nm² and finally the foot print of the PEG_10 000 correspond to 1/0.393 ∼ 2.54 nm².”

The Royal Society of Chemistry apologises for these errors and any consequent inconvenience to authors and readers.

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