Comprehensive tuning of bioadhesive properties of polydimethylsiloxane (PDMS) membranes with controlled porosity

Abstract

Polydimethylsiloxane (PDMS)-based elastomers have become the de facto platform for various biomedical applications. But the stable attachment of biomolecules to PDMS for more robust and long-term performance of the PDMS-based devices has been a significant challenge, owing to its unique physical properties (e.g. hydrophobicity, dynamic molecular mobility). Herein, the PDMS membrane with tunable surface porosity is developed via high-pressure saturated steam technology in order to promote a strong and lasting bioadhesion to the PDMS membrane without additional processing steps. The resulting porous PDMS membranes demonstrate enhanced physical properties (e.g. Young’s modulus, roughness, and air permeability), which is dependent on the membrane thickness. The bioactivity of porous PDMS membranes, evaluated by measuring the adhesion of various biomolecules and bioactivity of cells, shows significant improvement over conventional non-porous control. This effect can be attributed to the strong physical adsorption on the porous PDMS membrane by increased surface roughness and stiffness. In sum, the porous PDMS membrane provides a simple and yet highly effective platform to create bioactive surface for various biomedical devices.

Multiscale Control of Nanofiber-Composite Hydrogel for Complex 3D Cell Culture by Extracellular Matrix Composition and Nanofiber Alignment

“…For evaluating the efficiency of nanofiber alignment by the magnetic field, the angular distribution of nanofibers was obtained and analyzed [ 37 , 43 ]. Briefly, the fluorescent image of nanofibers within hydrogel was first obtained with a scanning confocal microscope (FV1000, Olympus).…”

Polymeric and biological membranes for organ-on-a-chip devices

“…However, the composition and intrinsic stiffness of PDMS differs greatly from those of the native ECM 3 , impacting cellular growth and adhesion. Furthermore, PDMS hydrophobicity hinders biomolecule attachment and protein adsorption 79 . Nevertheless, due to the gas permeability of PDMS, it is a suitable biochip material because its conditions resemble aerobic physiological conditions 80 .…”

“…Pore formation via high-pressure saturated steam has been explored by Jang and collaborators via an autoclaving cycle 79 . This method combines temperature, pressure, and moisture to generate micron-scale bubbles that become pores once PDMS has been cured (Fig.…”

“…Relate those parameters with pore size and adhesion to DNA, and collagen. 79 20 μl/min N/A High-pressure saturated steam Thermal treatment 40 μm 5 µm Parylene-C, collagen (platelets) PDMS Organ-on-a-chip: Viability of cell culturing: Human umbilical endothelial cells (HUVEC) and MDA-MB-231 (MDA) cells 14 N/A N/A Photolithography, dry and wet etching PDMS/toluene mortar; Oxygen plasma 1–4 μm 2–10 μm; 8–65% Fibronectin (HUVEC-primary, MDA-cancer) SiO 2 Chip: Ultrathin membrane for support of physiologically relevant cellular interactions Optically transparent Human umbilical vein endothelial cells (HUVECs) spread and proliferate on these membranes. 69 N/A N/A Photolithography and reactive ion etching Ozone 300 nm (comparable in thickness to the vascular basement membrane of 100–300 nm) 0.5 and 3 μm; 27.5% Geltrex (Life Technologies, California) HUVECs PLGA Lung tumor: Gefitinib drug testing Permeability, coculture 1 N/A N/A Electrospinning PLGA direct sealing 3 μm NA, nanofiber (A549 epithelial cells) Collagen-elastin Lung: Air‒blood barrier replication, exposed to mechanical forces Gold mesh to mimic alveolar size and structure 3 N/A Strain 10%; 4.0 kPa Gelation Double tape 10 μm hAEpCs (primary cells) Collagen Kidney: Endothelial-epithelial exchange interface, reabsorption mechanism 137 10 µl/min Wall shear stress ~1–10 dyne/cm 2 N/A Compression molding Screwing 25 μm NA hRVTU, HUVECs Collagen Colon: Suitability of membrane for OOC, comparison w/Transwell ® Microstructure, transport and cell viability 136 N/A, media changed daily N/A Lyophilization Sandwiching ~15 μm ~10.2 μm ...…”

Flow analysis on microcasting with degassed polydimethylsiloxane micro-channels for cell patterning with cross-linked albumin

“…Therefore, high gas solubility and the actual gas diffusion material can lead to a high pressure difference and larger air flux in the degassed PDMS. When it comes to the porosity, the gas-dissolving volume and accumulation recovery flux are assumed to be increased with the pore size and distance between neighboring pores [27]. On the other hand, the high flux may cause a shortened operable time for driving the solution.…”