Protein Surface Patterning Using Nanoscale PEG Hydrogels

Abstract

We have used focused electron-beam cross-linking to create nanosized hydrogels and thus present a new method with which to bring the attractive biocompatibility associated with macroscopic hydrogels into the submicron length-scale regime. Using amine-terminated poly(ethylene glycol) thin films on silicon substrates, we generate nanohydrogels with lateral dimensions of order 200 nm which can swell by a factor of at least five, depending on the radiative dose. With the focused electron beam, high-density arrays of such nanohydrogels can be flexibly patterned onto silicon surfaces. Significantly, the amine groups remain functional after e-beam exposure, and we show that they can be used to covalently bind proteins and other molecules. We use bovine serum albumin to amplify the number of amine groups, and we further demonstrate that different proteins can be covalently bound to different hydrogel pads on the same substrate to create multifunctional surfaces useful in emerging bio/proteomic and sensor technologies.

In situ photopolymerization of PEGDA‐protein hydrogels on nanotube surfaces

“…62 Multifunctional bovine serum albumin (BSA)-amplified PEG-NH 2 nanogels have been utilized in designing protein chips for biosensors. 63 To construct nanoscale hydrogels with controlled morphologies, researchers have frequently used templating approaches as well. For example, liposomes have also been used to synthesize nanoscale hydrogels consisting of PEG-diacrylate (PEG-DA) via photopolymerization.…”

3-Dimensional Hydrogel Printing via Electron Crosslinking

“…Typically, 3D printing of hydrogels is brought about by injection-type printers and optical curing [2]. The resolution of such an optical curing has been of the order of 0.1 mm to 1mm.On the other hand, lithographic patterning using electron beam is widely available and a rather common technique which can be used for beam induced triggering of the cross-linking process [3][4][5]. While this technique is currently used for 2D pattern formation, there is a shortage of data on the 3-dimensionality of the features formed using electron beam.…”

“…On the other hand, lithographic patterning using electron beam is widely available and a rather common technique which can be used for beam induced triggering of the cross-linking process [3][4][5]. While this technique is currently used for 2D pattern formation, there is a shortage of data on the 3-dimensionality of the features formed using electron beam.…”

A Micropatterned Hydrogel Platform for Chemical Synthesis and Biological Analysis

“…[1][2][3][4][5][6][7] A number of researchers have recognized that three-dimensional (3D) hydrogels may provide a viable alternative to two-dimensional surfaces for biomedical applications involving proteins and whole cells. [6,[8][9][10][11][12] The ideal hydrogel material for biochip applications would i) be easily micropatterned, ii) contain a high density of functional groups to allow incorporation of biomolecules, iii) provide a passive background, thus preventing non-specific protein adsorption, iv) be highly hydrated (semiwet or gel-like), thus mimicking the natural environment of cells and proteins, and v) be optically transparent, allowing for unimpaired optical assessment of results. Incorporation of biomolecule ligands into the hydrogel structure is usually done during the assembly [9] or polymerization [10,11] process or afterwards, e.g., by laser-light-initiated polymerization.…”

“…A number of microfabrication techniques have been developed to generate microscopic patterns on material surfaces. These include i) photolithography [18] using photomasks, ii) soft lithography, [19] which is a set of techniques that make use of an elastomeric "soft" material, commonly polydimethylsiloxane (PDMS), iii) electron-beam patterning, [12] and iv) direct printing. We investigated the use of three of these methods for micropatterning of PEGA (Fig.…”