{"title":"Reversible, stable and uniform SERS in a Y-shaped microfluidic chip: chemical imaging of concentration gradients","authors":"Fabien Chauvet","doi":"10.1007/s10404-024-02740-0","DOIUrl":null,"url":null,"abstract":"<div><p>Imaging of chemical composition in microfluidic chips is addressed using Surface Enhanced Raman Spectroscopy (SERS). The Y-shaped SERS microfluidic chip used is fabricated by xurography and an electrodeposition method is employed to form a thin nanostructured silver layer over the bottom glass wall of the main microchannel. Used as an immobilized SERS substrate, this layer of silver nanocrystals exhibits an analytical enhancement factor of 5.10<span>\\(^4\\)</span> uniformly distributed over its surface (RSD < 7%). These good performances allow the quantitative imaging of transverse diffusion profiles of Crystal Violet (CV) at low concentrations (<span>\\(10^{-8}-10^{-6}\\)</span> mol/L). The SERS measurement turns out to be reversible at high laser power and this is explained by the thermal desorption of adsorbed CV (photothermal effect). However, too high heating leads to a low amount of adsorbed species and a low SERS signal. This effect is limited by using a fast enough flow inducing a cooling effect. A compromise must be found between laser power and liquid flow rate to enable a reversible and sensitive SERS measurement in the chip. These findings should contribute to the development of imaging, in microfluidic conditions, of the spatiotemporal dynamics of weakly concentrated key molecules involved in chemical, biochemical or biological processes.</p></div>","PeriodicalId":706,"journal":{"name":"Microfluidics and Nanofluidics","volume":null,"pages":null},"PeriodicalIF":2.3000,"publicationDate":"2024-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Microfluidics and Nanofluidics","FirstCategoryId":"5","ListUrlMain":"https://link.springer.com/article/10.1007/s10404-024-02740-0","RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"INSTRUMENTS & INSTRUMENTATION","Score":null,"Total":0}
引用次数: 0
Abstract
Imaging of chemical composition in microfluidic chips is addressed using Surface Enhanced Raman Spectroscopy (SERS). The Y-shaped SERS microfluidic chip used is fabricated by xurography and an electrodeposition method is employed to form a thin nanostructured silver layer over the bottom glass wall of the main microchannel. Used as an immobilized SERS substrate, this layer of silver nanocrystals exhibits an analytical enhancement factor of 5.10\(^4\) uniformly distributed over its surface (RSD < 7%). These good performances allow the quantitative imaging of transverse diffusion profiles of Crystal Violet (CV) at low concentrations (\(10^{-8}-10^{-6}\) mol/L). The SERS measurement turns out to be reversible at high laser power and this is explained by the thermal desorption of adsorbed CV (photothermal effect). However, too high heating leads to a low amount of adsorbed species and a low SERS signal. This effect is limited by using a fast enough flow inducing a cooling effect. A compromise must be found between laser power and liquid flow rate to enable a reversible and sensitive SERS measurement in the chip. These findings should contribute to the development of imaging, in microfluidic conditions, of the spatiotemporal dynamics of weakly concentrated key molecules involved in chemical, biochemical or biological processes.
期刊介绍:
Microfluidics and Nanofluidics is an international peer-reviewed journal that aims to publish papers in all aspects of microfluidics, nanofluidics and lab-on-a-chip science and technology. The objectives of the journal are to (1) provide an overview of the current state of the research and development in microfluidics, nanofluidics and lab-on-a-chip devices, (2) improve the fundamental understanding of microfluidic and nanofluidic phenomena, and (3) discuss applications of microfluidics, nanofluidics and lab-on-a-chip devices. Topics covered in this journal include:
1.000 Fundamental principles of micro- and nanoscale phenomena like,
flow, mass transport and reactions
3.000 Theoretical models and numerical simulation with experimental and/or analytical proof
4.000 Novel measurement & characterization technologies
5.000 Devices (actuators and sensors)
6.000 New unit-operations for dedicated microfluidic platforms
7.000 Lab-on-a-Chip applications
8.000 Microfabrication technologies and materials
Please note, Microfluidics and Nanofluidics does not publish manuscripts studying pure microscale heat transfer since there are many journals that cover this field of research (Journal of Heat Transfer, Journal of Heat and Mass Transfer, Journal of Heat and Fluid Flow, etc.).