Thin Poly(Di(Ethylene Glycol)Methyl Ether Methacrylate) Homopolymer Brushes Allow Controlled Adsorption and Desorption of PaTu 8988t Cells

Abstract

Poly(di(ethylene glycol)methyl ether methacrylate) (PDEGMA) brushes, which are known to suppress protein adsorption and prevent cell attachment, are reported here to possess interesting and tunable thermoresponsive behavior, if the brush thickness is reduced or the grafting density is altered. PDEGMA brushes with a dry ellipsometric thickness of 5 ± 1 nm can be switched from cell adherent behavior at 37 °C to cell nonadherent at 25 °C. This behavior coincides with the temperature-dependent irreversible adsorption of fibronectin from phosphate saline buffer and proteins present in the cell culture medium, as unveiled by surface plasmon resonance measurements. Unlike for tissue culture polystyrene reference surfaces, swelling of the PDEGMA chains below the lower critical solution temperature results in the absence of paxillin and actin containing cellular filaments responsible for cell attachment. These tunable properties of very thin homopolymer PDEGMA brushes render this system interesting as an alternative thermoresponsive layer for continuous cell culture or enzyme-free cell culture systems.

Toward Label-Free Selective Cell Separation of Different Eukaryotic Cell Lines Using Thermoresponsive Homopolymer Layers

“…The LCST of PDGMA was reported to be 26 °C (for the bulk), , which increases to 32–34 °C for brushes. , In protein adhesion studies, we have previously determined an apparent surface transition temperature for end-grafted PDEGMA, which was reported to depend linearly on the PDEGMA thickness. ,, It increased from 35 °C for 5 nm thick PDEGMA layers to 48 °C at 23 nm. A very similar change in transition temperature could be achieved via a change of the PDEGMA grafting density, presumably via a transition from the mushroom to the brush regime.…”

“…Similarly, Dworak et al reported on poly­[tri­(ethylene glycol) ethyl ether methacrylate]-coated surfaces, polymerized on a solid substrate, which were employed for adhesion of fibroblasts and cell sheet formation as well as temperature-stimulated harvesting . More recently, PDEGMA homopolymer brushes were investigated and utilized for pancreatic tumor cell culture and cell detachment. − …”

“…Here, we report on a novel approach for sorting eukaryotic cells from ultrathin (5 ± 1 nm) homopolymer PDEGMA layers in an attempt to complement the known systems and to broaden the scope of feasible cell separation systems (Scheme ). PDEGMA coatings of the 5 ± 1 nm ellipsometric dry film thickness allow the propagation of various cell lines. , While thick PDEGMA brush layers (dry ellipsometric thickness > 10 nm) were shown to be resistant to protein attachment and do not support adherent cells, irrespective of the cell medium temperature, thinner layers or layers with reduced grafting density, which are presumably in the mushroom regime, effectively balance protein attachment and LCST-like stimulus response. , Hence upon cooling from 37 °C to a lower temperature, these layers swell profoundly and may release attached cells. ,, Because the dissimilar cell adhesion strengths of different cell types on the same protein modified surface can be varied by exploiting the temperature-dependent protein adhesion on PDEGMA as well as different cell adhesion properties on PDEGMA at 37 and 22 °C, cells of the pancreatic tumor cell line PaTu 8988t and NIH 3T3 fibroblast were successfully separated. This cell separation system establishes a simple and effective approach to sort targeted cells in a high yield from a mixture of adherent cells.…”

Probing of local polarity in poly(methyl methacrylate) with the charge transfer transition in Nile red

“…Prominent examples are the properties of substrate-supported ultrathin polymer films, in which the values of the glass transition temperature ( T g ) and segmental mobilities were found to be altered. Likewise, this holds for transport properties, including polymer nanocapsule membrane permeability [1], enzyme-triggered bacterial sensors [2–5] and intelligent self-controlled drug delivery systems [4,6–10], as well as dynamics of polymers at interfaces [11].…”

Bioinspired, Mechano‐Regulated Interfaces for Rationally Designed, Dynamically Controlled Collection of Oil Spills from Water

“…In recent years, the so‐called smart materials arose and drew much attention in the scientific community. Smart materials are stimuli‐responsive materials, which react to various stimuli, such as illumination, pH, temperature, chemical trigger, magnetic field, electric field, and deformation . For example, Xue et al proposed a thermoresponsive block copolymer coated mesh to separate water and oil.…”