Shrink-Induced Silica Multiscale Structures for Enhanced Fluorescence from DNA Microarrays

Abstract

We describe a manufacturable and scalable method for fabrication of multiscale wrinkled silica (SiO2) structures on shrink-wrap film to enhance fluorescence signals in DNA fluorescence microarrays. We are able to enhance the fluorescence signal of hybridized DNA by more than 120 fold relative to a planar glass slide. Notably, our substrate has improved detection sensitivity (280 pM) relative to planar glass slide (11 nM). Furthermore, this is accompanied by a 30–45 times improvement in the signal-to-noise ratio (SNR). Unlike metal enhanced fluorescence (MEF) based enhancements, this is a far-field and uniform effect based on surface concentration and photophysical effects from the nano- to microscale SiO2 structures. Notably, the photophysical effects contribute an almost 2.5 fold enhancement over the concentration effects alone. Therefore, this simple and robust method offers an efficient technique to enhance the detection capabilities of fluorescence based DNA microarrays.

Separations-encoded microparticles for single-cell western blotting

“…The increase in the fluorescence intensity resulted in an enhanced SNR, defined as the ratio of the average fluorescence signal minus the mean background signal to the standard deviation of the background. (47) The noise on the dehydrated microparticles was noted to decrease by 1.5x (median SNR = 9.8, CV = 0.8, n = 392 microparticles) relative to the hydrated microparticles, SNR = 6.4 (CV = 0.4, n = 342 microparticles). The lower noise in dehydrated microparticles yields an improved analytical sensitivity.…”

Recent advances in plasmonic nanostructures for sensing: a review

“…11(e)]. 181 These highly enhancing MEF arrays are randomly oriented extended surfaces composed of two dissimilar metals (e.g., nickel and gold) that are shaped through repeated heating and cooling cycles. 182 Due to the different thermal expansion coefficients of the materials, the repeated heating and cooling generate a disordered, wrinkled surface with large areas of intense electric fields following plasmon generation.…”

“…Using these wrinkled substrates, MEF enhancements as great as 120-fold have been reported. 181 Although the exact mechanism for these extreme enhancements is still unknown, it has been shown that the enhancements are uniform across the surface and not associated with particular "hot spots," suggesting that large areas can be probed with uniform signal enhancement. 181,182 Furthermore, the fabrication technique is inexpensive, manufacturable, and scalable, making these plasmonic nanostructured surfaces a promising platform for MEF sensing.…”

Multi-scale silica structures for improved HIV-1 Capsid (p24) antigen detection

“…This strategy was expanded upon by Sharma, et al, who used the SiO 2 structures to enhance the fluorescence signal of hybridized DNA and to obtain lowered limits of detection for the model DNA hybridization assay. 17 Human immunodeficiency virus type 1 (HIV-1) is a lentivirus that causes the HIV infection. As of 2014, approximately 36.9 million people worldwide are living with HIV.…”