Covalently Attached Slippery Surface Coatings to Reduce Protein Adsorptions on Poly(dimethylsiloxane) Planar Surfaces and 3D Microfluidic Channels

Abstract

Silicone elastomers, such as poly(dimethylsiloxane) (PDMS), have a broad range of applications in basic biomedical research and clinical medicine, ranging from the preparation of microfluidic devices for organs-on-chips and ventriculoperitoneal shunts for the treatment of hydrocephalus to implantable neural probes for neuropharmacology. Despite the importance, the protein adsorptions on silicone elastomers in these application environments represent a significant challenge. Surface coatings with slippery lubricants, inspired by the Nepenthes pitcher plants, have recently received much attention for reducing protein adsorptions. Nevertheless, the depletion of the physically infused lubricants limits their broad applications. In this study, we report a covalently attached slippery surface coating to reduce protein adsorptions on PDMS surfaces. As demonstrations, we show that the adsorption of serum proteins, human fibrinogen and albumin, can be significantly reduced by the slippery surface coating in both planar PDMS surfaces and 3D microfluidic channels. The preparation of slippery surface coatings relies on the acid-catalyzed polycondensation reaction of dimethyldimethoxysilane, which utilizes a low-cost and scalable dip-coating method. Furthermore, cell metabolic activity and viability studies demonstrate the biocompatibility of the surface coating. These results suggest the potential applications of slippery surface coatings to reduce protein adsorptions for implantable medical devices, organs-on-chips, and many others.

High Permeance Polyamide Nanofiltration Membranes Based on Poly(l-lactic acid) Electrospun Nanofibrous Membranes with Controlled Hydrophilicity

“…Therefore, it is difficult to directly form a dense and defect-free PA layer on such a substrate. There are various methods to hydrophilize the substrates, such as surface coating, chemical grafting, and layer-by-layer assembly. − The introduction of hydrophilic additives during the electrospinning process is a convenient and effective method of fabricating hydrophilic membranes. The hydrophilicity can be controlled by the contents of the additives.…”

Functional PDMS Elastomers: Bulk Composites, Surface Engineering, and Precision Fabrication

“…Zhang et al successfully mitigated this by covalently forming a slippery coating on PDMS surfaces using acid-catalyzed hydrolysis and condensation of dimethyldimethoxysilane, which effectively reduced protein uptake. [277] Additionally, enhancing PDMS surface energy by adding different quantities of PDMS-(60-70% ethylene oxide) block copolymers can significantly control fluid flow properties. [278] While PDMS microfluidics techniques are relatively mature, for further details, we direct interested readers to the review by Zhao et al [262]…”

Controlling Anti-Penetration Performance by Post-Grafting of Fluorinated Alkyl Chains onto Polystyrene-block-poly(vinyl methyl siloxane)

“…Control of penetration, the phenomenon of small molecules passing through a polymer layer, is highly desired in many applications, such as anticorrosion of metal substrates, 1 antigraffiti coatings, 2 wastewater treatment, 3 and gas separation. 4 In addition to these uses, polydimethylsiloxane (PDMS) is widely employed as a surface coating material for anti-fouling, 5 anti-protein, 6 anti-friction, 7 anti-icing, 8 and self-cleaning applications 9−11 due to its low surface energy of 20.4 mN/ m 12 and the ability of PDMS coatings to covalently bond to a broad range of substrates. 13−16 The penetration of small molecules, such as solvent molecules, in PDMS materials is common and occurs in microfluid devices, 17,18 membranes, 19,20 and sensors, 21,22 which is known to lead to swelling of PDMS in some cases 23 and produce changes to its chemical and physical properties.…”

“…Control of penetration, the phenomenon of small molecules passing through a polymer layer, is highly desired in many applications, such as anticorrosion of metal substrates, anti-graffiti coatings, wastewater treatment, and gas separation . In addition to these uses, polydimethylsiloxane (PDMS) is widely employed as a surface coating material for anti-fouling, anti-protein, anti-friction, anti-icing, and self-cleaning applications − due to its low surface energy of 20.4 mN/m and the ability of PDMS coatings to covalently bond to a broad range of substrates. − The penetration of small molecules, such as solvent molecules, in PDMS materials is common and occurs in microfluid devices, , membranes, , and sensors, , which is known to lead to swelling of PDMS in some cases and produce changes to its chemical and physical properties. ,,− Furthermore, the liquid-like behavior of PDMS (due to its low rotation barrier around the Si–O bond (3.3 kcal/mol), weak inter-/intrachain interactions, and the low glass transition temperature of PDMS (−127 °C)) not only results in dynamic omniphobicity (a surface property repelling both polar and nonpolar solvents and allowing liquid droplets to roll off easily at small tilting angles) on its brush-type coatings , but can also enhance the ability of small molecules to penetrate a PDMS layer . Especially for coatings that are immersed in a penetrant for extended times, such as barrier materials or even hull marine antifouling coatings, the time-dependent penetration of unwanted small molecules may also be a key consideration in the selection of coating materials.…”