Comparison of Coatings from Reactive Star Shaped PEG-stat-PPG Prepolymers and Grafted Linear PEG for Biological and Medical Applications

Abstract

Grafting of poly(ethylene glycol) (PEG) is a common strategy for reducing nonspecific interactions of surfaces with proteins. We have used grafting at "cloud point" solution conditions that ensures maximum grafting density of linear methoxy terminated PEG-aldehyde (mPEG-ald, M(w) = 5000 and 30000). In an alternative approach, surfaces were modified with layers prepared from isocyanate terminated, star shaped poly(ethylene glycol-stat-propylene glycol) prepolymers (80% ethylene glycol, six arms, M(w) = 3000, 12,000, and 18,000; this compound will be referred to as "Star PEG" in the text). Due to the highly reactive endgroups, these molecules form a dense network on the substrate with a high polymer surface coverage. The two systems were compared regarding their ability to prevent unspecific adsorption of insulin and lysozyme. The layers were analyzed by ellipsometry, contact angle measurements, and XPS. Protein adsorption was monitored by surface MALDI-TOF MS and fluorescence microscopy. No protein adsorption could be detected on Star PEG coatings and on mPEG-ald 5000, whereas mPEG-ald 30,000 could only prevent adsorption of lysozyme but not of the smaller insulin.

Improved Performances of Intraocular Lenses by Poly(ethylene glycol) Chemical Coatings

“…Otsuka et al 38,39 reported a contact angle of water-in-air of 47°, to be compared to 40°in this work, for a PEG 5000 coating.…”

Surface Grafting of PEO‐Based Star‐Shaped Molecules for Bioanalytical and Biomedical Applications

“…[33,34] The non-fouling properties of star PEG coatings were compared to surfaces modified with linear methoxy-terminated PEO chains and BSA. [33,73] In both cases, the star PEG system exhibited superior non-fouling properties. In contrast to the prevention of protein adsorption, films with thicknesses between 3 and 10 nm were not able to prevent non-specific cell adhesion under standard cell culture conditions (10% fetal calf serum).…”

“…These amino groups have been detected by reaction with the non-fluorescent 4-chloro-7-nitrobenzofurazan (NBF) to the fluorescent derivative [34] and by gas-phase derivatization with pentafluorobenzaldehyde followed by X-ray photoelectron spectroscopy (XPS) analysis. [73] Thus, the surface will be covered by a densely crosslinked layer of PEG chains that contains a fraction of free amine groups that can be further functionalized. [74] Figure 3 shows the chemical reactions that occur during film formation and presents a model of the resulting surface coatings.…”

Water-soluble starlike poly(acrylic acid) graft polymer: preparation and application as templates for silver nanoclusters

“…Recently, they have been widely investigated in terms of micellar aggregation in solution because of their well-defined macromolecular architecture [27,28]. In addition, the aggregates of star polymers which have amino groups, hydroxyl groups or carboxylic acid groups in the side chains have versatile applications in medicine and biology [29][30][31], catalytical chemistry [32][33][34], and nanotechnology [35,36]. For example, Kumacheva's group recently reported fast photoactivated synthesis of stable fluorescent silver nanoclusters [37] and other semiconductor or magnetic nanoparticles [38] by employing polymer microgels with concentrated carboxyl groups as templates.…”