Micropatterned avidin arrays on silicon substrates via photolithography, self‐assembly and bioconjugation

Abstract

Processes for micropatterning protein arrays on inorganic substrates have gained attention in the development of biosensors and clinical diagnostics. This study demonstrates a chemically selective method based on photolithographic deposition of gold patterns with the subsequent attachment of functionalized alkanethiols via molecular self-assembly. Selective capping of carboxy groups on alkanethiols by N-hydroxysuccinimide esters allowed the deposition of methoxypoly(ethylene glycol) silane as a blocking agent on unpatterned regions. Carboxylates were used to couple a form of avidin to create a microarray of protein. This microarray was successfully probed with biotinylated quantum dots. In-process characterization methods included grazing-angle Fourier-transform IR spectroscopy, ellipsometry, contact-angle goniometry, atomic-force microscopy and fluorescence microscopy.

Two-Stage Capture Employing Active Transport Enables Sensitive and Fast Biosensors

“…(19) The number of analytes captured by the sensor patch in time t is then given by In current microarrays, the sensor radius varies between 10 and 200 μm and a large number of analyte molecules is rapidly accumulated. 20−22 Unfortunately, the accumulation of analyte onto nanoscale sensors is extremely slow and necessitates collection times of many hours (Figure 2). 4,23 Techniques to increase the analyte flux, e.g., stirring or flow, are effective for sensors larger than 10 μm(21) but are not very effective in increasing the analyte flux to nanoscale sensors.…”

Direct Determination of Plasmon Enhancement Factor and Penetration Depths in Surface Enhanced IR Absorption Spectroscopy

“…The bulk absorption spectra of 6-FCHT in the C–H stretch region as a function of various concentrations in dDMSO is shown in Figure . For determination of the bulk molar absorptivity of the hydrocarbon stretches of 6-FCHT, we used the peaks at 2853 and 2929 cm –1 , which correspond to the symmetric and asymmetric CH 2 stretches of the hydrocarbon chain. − The baseline corrected spectra and the absorbance values at 2853 and 2929 cm –1 are plotted against the concentration of 6-FCHT as shown in Figure . The slope obtained from the absorbance verses concentration plot is the product of molar absorptivity and path length (97 μm in our case).…”