Cellular Uptake of PEO Surface-Modified Nanoparticles: Evaluation of Nanoparticles Made of PLA: PEO Diblock and Triblock Copolymers

Abstract

Nanoparticles with either physically adsorbed or covalently bound poly(ethylene oxide) (PEO) coatings were produced from various combinations of poly(lactic acid) (PLA) and diblock or triblock copolymers of PLA and PEO. The particles were produced by the salting-out process and purified by the cross-flow filtration technique. The amount of PEO at the nanoparticle surface, as well as the residual amount of emulsifier poly(vinyl alcohol) were assessed, with a good correlation with expected values. Stability of the nanoparticulate suspensions was studied at 4 degrees C and after freezing under various conditions for up to 6 months. The nanoparticle redispersibility after storage was related to the thermal behavior of the PEO coatings. The in vitro cellular uptake of the different types of nanoparticles was compared by flow cytometry after incubation with human monocytes in serum and in plasma. The influence of the PEO molecular weight and surface density on the particle uptake was especially marked for the diblock and triblock copolymer formulations, with a decrease in uptake of up to 65% with one of the diblock copolymer formulations. Nanoparticles made of triblock copolymer with short PEO chains at their surface in the postulated "loop conformation" proved to be as resistant to cellular uptake as nanoparticles made of diblock copolymers with PEO chains in the "brush conformation".

Galactosylated Poly(N-isopropylacrylamide) Hydrogel Submicrometer Particles for Specific Cellular Uptake within Hepatocytes

“…From a practical viewpoint, prolonged circulation in the blood stream and increased targeting efficiency to a specific tissue are also desirable. For this purpose, polyethylene glycol could be conjugated on the surface of hydrogel submicrometer particles to reduce adsorption of serum proteins on the surface, as previously reported in many nanoparticulate delivery studies (34,35).…”

Block Copolymer ‘Stealth’ Nanoparticles for Chemotherapy: Interactions with Blood Cells In Vitro

“…Upon reaching the tumor site, these drug carriers work on the principle of enhanced permeability and retention (the EPR effect) as the blood vessels surrounding tumors are highly permeable, and less subject to drainage. [5][6][7][8] In this context, it has been found that long chain-lengths of PEG result in very low protein adsorption when interacting with cells, thereby inhibiting RES uptake. [9][10][11] However, from these studies, it is not clear if the effect is simply a consequence of segment length or whether the overall surface density and configuration of the PEG on the surface has any bearing on RES interaction.…”

Key criteria for the design of polymeric stabilizers for aqueous titanium dioxide dispersions of high solid content

“…Compatibilization of immiscible polymer blends is a well known example [11]. Control of the crystallization of inorganic particles (CaCO 3 , ZnO) [12], formation of micro-or nanoparticles for drug encapsulation are other non-limiting examples [13]. The reader can find more information in recent reviews [14].…”