The role of PEG conformation in mixed layers: from protein corona substrate to steric stabilization avoiding protein adsorption

Comenge, Joan

doi:10.14293/s2199-1006.1.sor-matsci.a0z6om.v1

Cited by 9 publications

(8 citation statements)

References 48 publications

(55 reference statements)

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“…While for MUA and other small alkyl thiols a footprint of 0.17 nm 2 is established, 3,58 PEG molecules, thiolated DNA, peptides and proteins can have much larger footprints up to several nm 2 per molecule. Therefore, the assessment of the ligand layer composition based on the composition of the reaction mixture of ligands before conjugation is difficult: 59 Will the ratio of the ligand reaction mixture transfer to the number ratio of ligands bound to the particle surface or the relative areas they occupy? Or will one ligand bind preferentially?…”

Section: Synthesis and Characterization Of Mixed Ligand Layersmentioning

confidence: 99%

Ligand Layer Engineering To Control Stability and Interfacial Properties of Nanoparticles

et al. 2016

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The use of mixed ligand layers including poly(ethylene glycol)-based ligands for the functionalization of nanoparticles is a very popular strategy in the context of nanomedicine. However, it is challenging to control the composition of the ligand layer and maintain high colloidal and chemical stability of the conjugates. A high level of control and stability are crucial for reproducibility, upscaling, and safe application. In this study, gold nanoparticles with well-defined mixed ligand layers of α-methoxypoly(ethylene glycol)-ω-(11-mercaptoundecanoate) (PEGMUA) and 11-mercaptoundecanoic acid (MUA) were synthesized and characterized by ATR-FTIR spectroscopy and gel electrophoresis. The colloidal and chemical stability of the conjugates was tested by dynamic light scattering (DLS), small-angle X-ray scattering (SAXS), and UV/vis spectroscopy based experiments, and their interactions with cells were analyzed by elemental analysis. We demonstrate that the alkylene spacer in PEGMUA is the key feature for the controlled synthesis of mixed layer conjugates with very high colloidal and chemical stability and that a controlled synthesis is not possible using regular PEG ligands without the alkylene spacer. With the results of our stability tests, the molecular structure of the ligands can be clearly linked to the colloidal and chemical stabilization. We expect that the underlying design principle can be generalized to improve the level of control in nanoparticle surface chemistry.

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Section: Synthesis and Characterization Of Mixed Ligand Layersmentioning

confidence: 99%

Ligand Layer Engineering To Control Stability and Interfacial Properties of Nanoparticles

et al. 2016

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“…8 However, working with mixtures of ligands could result in the absorption of the strongest binding ligand only 23 or in the phase separation of the two ligands at the surface of the nanoparticles, 24,25 instead of the formation of a mixed monolayer. Hence, the resulting ratio of ligands is often unknown 26,27 and cannot be readily quantified without releasing the ligands from the surface, 28,29 especially when AuNPs larger than a few nm are used. 30,31 The aim of the current work is to develop a new class of organic ligands that allows controlling the composition of mixed monolayers on AuNPs.…”

Section: Introductionmentioning

confidence: 99%

Controlled Functionalization of Gold Nanoparticles with Mixtures of Calix[4]arenes Revealed by Infrared Spectroscopy

Valkenier¹,

Malytskyi²,

Blond³

et al. 2017

Langmuir

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Labile ligands such as thiols and carboxylates are commonly used to functionalize AuNPs, though little control over the composition is possible when mixtures of ligands are used. It was shown recently that robustly functionalized AuNPs can be obtained through the reductive grafting of calix[4]arenes bearing diazonium groups on the large rim. Here, we report a calix[4]arene-tetradiazonium decorated by four oligo(ethylene glycol) chains on the small rim, which upon grafting gave AuNPs with excellent stability thanks to the C-Au bonds. Mixtures of this calixarene and one with four carboxylate groups were grafted on AuNPs. The resulting particles were analyzed by infrared spectroscopy, which revealed that the composition of the ligand shell clearly reflected the ratio of calixarenes that was present in solution. This strategy opens the way to robustly protected AuNPs with well-defined numbers of functional or postfunctionalizable groups.

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“…The PEG grafting density is directly related to the biorepulsive properties of PEG layers ,− and a higher grafting density seems to be advantageous in terms of immune response. , The inner hydrophobic region formed by the densely packed alkyl chains reduces displacement reactions at the AuNP surface leading to strongly decreased opsonization and phagocytosis . Most importantly for this study the MUA-spacer allowed for the controlled design of mixed ligand layers as tested previously with PEGMUA/MUA mixtures .…”

Section: Resultsmentioning

confidence: 80%

“…. To detect changes in the surface charge or hydrodynamic diameter of NPs or both, gel electrophoresis is an alternative method that provides various information in a straightforward experiment. ,,− It has to be noted that based on gel electrophoresis protein adsorption cannot be fully excluded because weakly adsorbed proteins can be stripped off during the experiment, but it can reliably determine trends, in particular if the NP physicochemical characteristics like hydrodynamic diameter and surface charge are significantly altered. Because the mixed ligand layers studied herein consist of charged ligands (the targeting and control ligands) and neutral ligands (PEGMUA), the relative composition of the ligand layers can be easily determined with gel electrophoresis .…”

Section: Resultsmentioning

confidence: 99%

Defined Coadsorption of Prostate Cancer Targeting Ligands and PEG on Gold Nanoparticles for Significantly Reduced Protein Adsorption in Cell Media

Höeg

Schulz

Graf³

et al. 2022

J. Phys. Chem. C

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A study on the surface chemistry of gold nanoparticles (AuNPs) utilizing gel electrophoresis is presented. The molecular design of targeting and stabilizing PEG ligands allows one to combine them in mixed ligand layers with control of relative composition. For all tested targeting and control ligands, coadsorption of PEG significantly reduces protein adsorption and matrix effects of cell media as compared to conjugates without PEG. Introducing carboxylic acid groups into the PEG ligand layer does not lead to increased protein adsorption as shown with carboxylic acid terminated PEG ligands. The controlled adsorption of PEG ligands with different molecular weights is used to disentangle the effects of particle charge and hydrodynamic diameter. Taken together, this study provides directions for the functionalization of nanoparticles to obtain conjugates which are well-defined in terms of composition and colloidally stable in complex media. This is in particular relevant for targeting applications and cell experiments.

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The role of PEG conformation in mixed layers: from protein corona substrate to steric stabilization avoiding protein adsorption

Cited by 9 publications

References 48 publications

Ligand Layer Engineering To Control Stability and Interfacial Properties of Nanoparticles

Ligand Layer Engineering To Control Stability and Interfacial Properties of Nanoparticles

Controlled Functionalization of Gold Nanoparticles with Mixtures of Calix[4]arenes Revealed by Infrared Spectroscopy

Defined Coadsorption of Prostate Cancer Targeting Ligands and PEG on Gold Nanoparticles for Significantly Reduced Protein Adsorption in Cell Media

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