There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

[신간의 별자리x] 우리/미술, 그리고 ‘슬픔의 박물관’

基礎講座 電気泳動(Electrophoresis)

Sensitive optical biosensors for unlabeled targets: a review.

We present ink-jet fabrication of optofluidic surface enhanced Raman spectroscopy (SERS) devices with no micro/nano-fabrication required. This novel, ultra-low-cost technique enables on-demand fabrication of SERS devices for lab and field use.

Ink-Jet-Printed Optofluidic SERS for Molecular Analysis

Improving the portability of diagnostic medicine is crucial to alleviating global access-to-care deficiencies. This requires not only designing devices that are small and lightweight but also autonomous and independent of electricity. Here, we present a strategy for conducting automated multi-step diagnostic assays using chemically generated, passively regulated heat. Ligation and polymerization reagents for Rolling Circle Amplification of nucleic acids are separated by melt-able phase-change partitions, thus replacing precise manual reagent additions with automated partition melting. To actuate these barriers and individually initiate the various steps of the reaction, field ration heaters exothermically generate heat in a thermos while fatty acids embedded in a carbonaceous matrix passively buffer the temperature around their melting points. Achieving multi-stage temperature profiles extends the capability of instrument-free diagnostic devices and improves the portability of reaction automation systems built around phase-change partitions.

/pdf/multi-stage-chemical-heating-for-instrument-free-biosensing-3g3bfbeqb9.pdf

Multi-stage chemical heating for instrument-free biosensing

Surface Enhanced Raman spectroscopy (SERS) provides significant improvements over conventional methods for single and multianalyte quantification. Specifically, the spectroscopic fingerprint provided by Raman scattering allows for a direct multiplexing potential far beyond that of fluorescence and colorimetry. Additionally, SERS generates a comparatively low financial and spatial footprint compared with common fluorescence based systems. Despite the advantages of SERS, it has remained largely an academic pursuit. In the field of biosensing, techniques to apply SERS to molecular diagnostics are constantly under development but, most often, assay protocols are redesigned around the use of SERS as a quantification method and ultimately complicate existing protocols. Our group has sought to rethink common SERS methodologies in order to produce translational technologies capable of allowing SERS to compete in the evolving, yet often inflexible biosensing field. This work will discuss the development of two techniques for quantification of microRNA, a promising biomarker for homeostatic and disease conditions ranging from cancer to HIV. First, an inkjet-printed paper SERS sensor has been developed to allow on-demand production of a customizable and multiplexable single-step lateral flow assay for miRNA quantification. Second, as miRNA concentrations commonly exist in relatively low concentrations, amplification methods (e.g. PCR) are therefore required to facilitate quantification. This work presents a novel miRNA assay alongside a novel technique for quantification of nuclease driven nucleic acid amplification strategies that will allow SERS to be used directly with common amplification strategies for quantification of miRNA and other nucleic acid biomarkers.

Surface Enhanced Raman Spectroscopy (SERS) methods for endpoint and real-time quantification of miRNA assays

We report the demonstration of an optofluidic surface enhanced Raman spectroscopy (SERS) device that leverages nanoporous microfluidics to dramatically increase the SERS performance. In this work, we utilize packed silica microspheres in a microfluidic channel to create a 3D nanoporous concentration matrix to achieve a detection limit of 400 attomoles of Rhodamine 6G in 2 minutes in a simple to fabricate microfluidic chip. Integrated fiber optics further enables the device to be relevant for portable applications.

3-D nanoporous optofluidic device for high sensitivity SERS detection

We report a surface-enhanced Raman spectroscopy device with on-chip mixing, integrated fiber optics, and nanofluidic concentration of Ag nanoclusters and adsorbed analytes. The device's detection limit is 100X better than open-channel microfluidics.

Ian M. White

Papers

Ink-Jet-Printed Optofluidic SERS for Molecular Analysis

Multi-stage chemical heating for instrument-free biosensing

Surface Enhanced Raman Spectroscopy (SERS) methods for endpoint and real-time quantification of miRNA assays

3-D nanoporous optofluidic device for high sensitivity SERS detection

A nanoporous optofluidic SERS microsystem for sensitive and repeatable on-site detection of melamine