Subpicomolar Iron Sensing Platform Based on Functional Lipid Monolayer Microarrays

Abstract

International audienceWe report herein the fabrication of novel micro-arrays based on air-stable functional lipid monolayers over silicon using a combination of e-beam lithography and lift-off. We demonstrate these microarrays can be use as ultrasensitive platform for Kelvin probe force microscopy in sensing experiments. Specificity of the detection is given by the functional group grafted at the lipid headgroup. The arrays developed for the detection of ferric ions, Fe3+, using a gamma-pyrone derivative chelator, demonstrate subpicomolar limit of detection with high specificity. In addition, the technique takes advantage of the structure of the array with the silicon areas playing the role of reference for the measurement, and we determine critical pattern dimensions below which the probe size/shape impacts the measured results

Novel and Innovative Interface as Potential Active Layer in Chem-FET Sensor Devices for the Specific Sensing of Cs+

“…Nevertheless, prior to its implementation in a real device it is required to graft it efficiently on a suitable surface. In this context, we have recently demonstrated that SLM (Single Lipid Monolayer) [18][19][20][21] can be used as efficient organic dielectrics in Field Effect Transistors devices. Respectively we have implemented a methodology that ensures us to have SLM with unprecedented mechanical and electrical properties.…”

“…Firstly a sample of a free-OH lipid was assembled on an edge-tailored silicon prism to form a self-assembled monolayer (SAM) and then polymerized within the plane of the monolayer by applying a protocol mastered by our group to form 5. [18][19][20][21] The obtained SLM 5 was successfully characterized in situ; prior to grafting the host compound 4, using a homemade Infrared cell placed in an attenuated total reflectance mode Fourier-transform infrared (ATR-FTIR) spectrophotometer (see SI Figure S12). The initiation and propagation of the polymerization in the outer plane was initiated and ensured by the polycondensation of triethoxysilane group with the ester group on the top of the SLM 5 (Scheme 3).…”

Ultrathin Supported Lipid Monolayer with Unprecedented Mechanical and Dielectric Properties

“…This crosslinking, named herein reticulation 1 , consists of a radical reticulation reaction initiated by AAPH (2,2′‐Azobis(2‐methylpropionamidine) as a heat‐sensitive water‐soluble free radical initiator. At this stage the supported lipid monolayer exhibits sufficient stability to be rinsed with solvent or dried and can be further easily manipulated . Using this procedure, DC‐glycerol‐R monolayers were obtained and have been used as the starting point to generate the DC‐MTS and DC‐OTS layers as depicted in Figure .…”

“…This property has been successfully exploited in the fabrication of field‐effect transistors sensors based on modified SLMs, as ultrathin gate dielectric layers, directly immobilized at the surface of a H‐terminated silicon‐based channel . Additional experiments performed on SLM's arrays fabricated using harsh lift‐off processes, and used as capacitive sensing platform clearly confirmed these improvements . In these studies, SLMs were subjected to electric fields up to 6 MV cm −1 , i.e., to values much higher than those at which electroporation occurs.…”

Femtomolar detection of Cu2+ ions in solution using super-Nernstian FET-sensor with a lipid monolayer as top-gate dielectric

“…Additionally, these layers are extremely versatile and can be easily chemically customized to impart specific functionalities (Kenaan et al, 2018;Nguyen et al, 2013). Such layers were also used for the fabrication of micro-array as capacitive sensing platforms to detect and quantify ferric ions concentrations in solution (Kenaan et al, 2016). In both these studies the very low LOD is ascribed to the high capacity and exceptional insulating properties of the ultra-thin insulating layer and confirms the interest of such lipid-FET for the detection of low concentration small ions in solution.…”