Gel-pad microarrays templated by patterned porous silicon for dual-mode detection of proteins

Abstract

A proof-of-concept study demonstrated the feasibility of a novel gel-pad microarray on porous silicon chips, by initiation of an atom transfer radical propagation (ATRP) polymerisation of (polyethylene glycol) methacrylate (PEGMA) with surface Si-H species, stepwise chemical conversions of the gel membrane to an NTA-Ni2+/histidine-tagged protein system, and matrix-assisted laser desorption/ionisation mass spectroscopy (MALDI MS) and fluorescence detections.

Lab‐on‐a‐plate: Extending the functionality of MALDI‐MS and LDI‐MS targets

“…Fluorometric detection is non-destructive and will therefore not affect the subsequent ionization step. Examples include single cell visualization with fluorescence followed by NIMS (Northen et al, 2007), a dual fluorescent/MALDI chip platform for analyzing enzymatic activity (Halim et al, 2009), gel-pad microarrays formed by patterning porous silicon for dual-mode detection of proteins by fluorescence and MALDI-MS (Chen et al, 2009), and a novel strategy for following chemical reactions carried out on the zeptomol (10 À21 mol) scale using ''attoreactors'' that are analyzed by both fluorescence and MALDI-MS (Anzenbacher & Palacios, 2009; see also Section IV.C). A single paper has even appeared dealing with DNA detection on a planar microwell plastic chip compatible with optical/fluorescence detection, MALDI-MS, and atomic force microscopic imaging (Ibáñez et al, 2008).…”

Covalently derivatized NTA microarrays on porous silicon for multi-mode detection of His-tagged proteins

“…Immobilization of biomolecules on the PSi surface has been reported by us and other groups recently [12][13][14][15]. Most widely-used immobilization strategies including physical adsorption, electrostatic and hydrophobic interactions, and chemical binding have been implanted onto the PSi surface [12][13][14][15][16][17][18].…”

“…Most widely-used immobilization strategies including physical adsorption, electrostatic and hydrophobic interactions, and chemical binding have been implanted onto the PSi surface [12][13][14][15][16][17][18]. These methods share some common disadvantages such as nonspecific adsorption, decrease of biological activity of immobilized protein, and uncontrolled orientation of attachment.…”

“…A well-established IMAC (immobilized metal-ion affinity chromatography) strategy that provides a standard tool for purification of proteins genetically tagged with a short sequence of six consecutive histidine (His) residues, has been developed for biochip applications. For example, NTA-Ni II (nitrilotriacetic acid) is a well-known system for chelation-based immobilization of His-tagged proteins [13,[19][20][21][22][23]. The chelate group of NTA can strongly bind to a nickel ion via four binding sites, leaving Ni II two vacant sites to coordinate with imidazole groups of His units on the tagged protein.…”

Porous Silicon Integrated Photonic Devices for Biochemical Optical Sensing

“…Silicon, and silicon related materials, is by far the most important and diffuse material for lab-on-chip applications due to the high development of the integrated circuits technology. Recently, porous silicon substrates have been proposed for reverse phase protein and DNA microarray (Ressine et al, 2007;Chen et al, 2009;Yamaguchi et al, 2007): small sensing area with high detection efficiency is the key feature in both applications, in which quantitative signals are generated by fluorescence and infrared spectroscopy, respectively. Alternatively, we have studied the fabrication process and the optical characterization by reflectometry of a microarray of PSi photonic devices as functional platform for label-free detection of biomolecular interactions (Rea at al., 2010b).…”