Porous polymer coatings as substrates for the formation of high-fidelity micropatterns by quill-like pens

Abstract

SummaryWe explored the potentials of microarray printing using quill-like microcantilevers onto solid supports that are typically used in microspot printing, including paper, polymeric nitrocellulose and nylon membranes. We compared these membranes with a novel porous poly(2-hydroxyethyl methacrylate-co-ethylene dimethacrylate) support (HEMA) with narrow pore size distribution in the 150 nm range, which demonstrated advantages in pattern definition, spot homogeneity, and consistent spot delivery of different dyes (phloxine B and bromophenol blue) with diameters of several micrometres. The bromophenol blue arrays on HEMA support were used to detect the presence of bovine serum albumin (BSA). In the presence of BSA, the fluorescence spectrum observed from the bromophenol blue microarray exhibited a significant red shift of the maximum emission wavelength. Our results show that the porous HEMA substrates can improve the fidelity and quality of microarrays prepared by using the quill-like microcantilevers. The presented method sets the stage for further studies using chemical and biochemical recognition elements, along with colorimetric and fluorometric sensors that can be spotted by this method onto flat porous polymer substrates.

Click‐Chemistry Immobilized 3D‐Infused Microarrays in Nanoporous Polymer Substrates

“…For reliable use, the microarrays should be stable, homogeneous and easy to read out, while at the same time, miniaturizing is desired for reduced use of consumables and sample. Recently, we have shown the advantageous properties of nanoporous poly(2‐hydroxyethyl methacrylate‐ co ‐ethylene dimethacrylate) (HEMA‐EDMA) polymer for the generation of miniaturized microarrays in comparison to conventional spotting substrates . The microarrays fabricated on the nanoporous HEMA‐EDMA polymer could feature smaller spot sizes (at least one order of magnitude less than in typical ink jet printing) while retaining sharper feature edges when compared to other commonly used substrates for spotting as paper, nitrocellulose and nylon membranes.…”

“…Alkyne modification of glass substrates allowed for the formation of covalently bound microarrays by spotting with molecules functionalized with the azide group . To combine the favorable properties of the nanoporous polymeric substrates (average pore size 150 nm) with the covalent binding demonstrated on the glass substrates, we here present an alkyne modification of the porous polymer (alkyne‐HEMA‐EMDA) allowing for click‐chemistry coupling of azides via copper(I)‐catalyzed azide‐alkyne cycloaddition (CuAAC) . This prominent click reaction found many applications, e.g., in the generation of nanosized molecular junctions .…”

Phospholipid arrays on porous polymer coatings generated by micro-contact spotting

“…Spotting with SPT probes on HEMA-EDMA polymer increases the spatial resolution of lipid pattern as compared to conventional spotting/ink jet printing on 3D substrates, such as PVDF or nitrocellulose membranes, from 50–300 µm in current commercial setups [ 26 – 27 ] to the presented average 6 µm features by µCS. The 3D nature of the spotted features (enabled by the infiltration of the ink into the nanoporous polymer) results in a higher signal intensity compared to similar arrays on strictly 2D substrates as glass [ 9 – 10 ]. As of now it is still unknown, just like in case of lipids spotted on PVDF membranes [ 7 ], how the polymer mesh accommodates lipid geometry and packaging, and how it affects the accessibility of the target lipid regions for the binding of proteins and antibodies.…”

“…The work presented here demonstrates the potential of nanoporous poly(2-hydroxyethyl methacrylate- co -ethylene dimethacrylate) (HEMA-EDMA) as a novel advantageous substrate for lipid arrays. Porous HEMA support, with pore size distribution in the range of 150 nm , has already demonstrated advantages in pattern definition, spot homogeneity, and consistent spot dimensions for different dye sensors (phloxine B and bromophenol blue) spotted in ethanol based inks [ 9 ]. In the present approach, the pores of the HEMA-EDMA support act as a mesh that contains lipid ink in a confined space, providing high pattern definition, and presenting more binding sites than would be available on a flat substrate [ 10 ].…”

Diamond Nanophotonic Circuits Functionalized by Dip‐pen Nanolithography

“…With fluorescence microscopy and atomic force microscopy we verify the site-specific surface modification and demonstrate guiding and coupling of fluorescent light in nanophotonic waveguides. Additionally, we demonstrate the delivery of ink solutions by microchannel cantilever spotting [35,36], exploiting a self-alignment process for functionalization of ring resonators as an alternative route for solvent based delivery of active material. Our approach holds promise for high throughput and high accuracy fabrication of biophotonic devices, which will enable applications in bio-sensing and bio-interfacing by the multiplexed introduction of active elements in form of functional ink mixtures.…”