Recently we exert the MTT test for 10 nm gold nanoparticles & gold nanorods (AR=3.5). Both of nanostructures were covered by CTAB molecule and highly toxic so pegilation approach have been chosen for decreasing cytotoxicity. our result are strange somehow because cytotoxicity of pegilated gold nanoparticles is higher than pegilated nanorods while we see a opposite results for nonpegilated nanostructures.
The presence of PEG residues on AuNPs impaired the viability of the ATII-like cell lines A549 and NCIH441. Interestingly, the presence of an excess of PEG on the surface of NPs will not only reduce the in vitro viability of the cell lines A549 and NCIH441, but also affected cellular proliferation and increased the release of lactate dehydrogenase (LDH). Furthermore, if ou do further investigation by transmission electron microscopy (TEM). you will observed that particles were internalized by active endocytosis in the cell lines A549 and NCIH441 within 3 hr. In addition, gold particles accumulated in membrane-bound vesicles and were not found freely dispersed in the cytoplasm.
Tha's why Pegylated AuNP's show more toxicity. I hope that answer will resolve your issue
The presence of PEG residues on AuNPs impaired the viability of the ATII-like cell lines A549 and NCIH441. Interestingly, the presence of an excess of PEG on the surface of NPs will not only reduce the in vitro viability of the cell lines A549 and NCIH441, but also affected cellular proliferation and increased the release of lactate dehydrogenase (LDH). Furthermore, if ou do further investigation by transmission electron microscopy (TEM). you will observed that particles were internalized by active endocytosis in the cell lines A549 and NCIH441 within 3 hr. In addition, gold particles accumulated in membrane-bound vesicles and were not found freely dispersed in the cytoplasm.
Tha's why Pegylated AuNP's show more toxicity. I hope that answer will resolve your issue.
One more point I want to add is that however Pegylation on the surface of gold nanoparticles might play a pivotal role in inducing cytotoxicity in vitro, but does not influence the uptake of the particles in human ATII-like cell lines.
Thanks Muhammad. Its kind of you to introduce me a manuscript that describe the molecular and cellular uptake procedure that you mentioned. and also why pegilated gold nanorods have a lower cytotoxic effect. does it related to the size or amount of surface bond PEG molecule (We use same concentration of gold (ppm) and PEG)?
My Pleasure Mohammad Amini
It is interesting to describe that Since gold nanorods stabilized with CTAB show strong cytotoxicity, so to modify these with polyethyleneglycol (PEG) for medical applications. PEG-modification is achieved by adding mPEG-SH in the CTAB solution, then, excess CTAB is removed by dialysis. PEG-modified gold nanoparticles shows a nearly neutral surface, and had little cytotoxicity in vitro.
A study is reported in which intravenous injection into mice, 54% of injected PEG-modified gold nanoparticles were found in blood at 0.5 h after intravenous injection, whereas most of gold was detected in the liver in the case of original gold nanorods stabilized with CTAB.
In short the results you have achieved in your study are right depending upon my description I have given and with reference to the literature reported.
If you have more question, I will be happy to answer you. But I think above-said description will be enough for you.
Best wishes
Thanks for Kind and valuable answer. based on you answer we should decrease the PEG concentration for Gold nanoparticles not for nanorods. I will be happy to have your MTT or LDH results on pegilatied gold structures. Thanks
- Different Protein Corona Formation
- PEGylation reduces but does not completely eliminate protein adsorption.
- Spherical PEGylated GNPs may adsorb a different set of proteins than PEGylated GNRs, leading to higher toxicity through an altered biointerface.
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