Harnessing the NEON data revolution to advance open environmental science with a diverse and data-capable community

It is a critical time to reflect on the National Ecological Observatory Network (NEON) science to date as well as envision what research can be done right now with NEON (and other) data and what training is needed to enable a diverse user community. NEON became fully operational in May 2019 and has pivoted from planning and construction to operation and maintenance. In this overview, the history of and foundational thinking around NEON are discussed. A framework of open science is described with a discussion of how NEON can be situated as part of a larger data constellation—across existing networks and different suites of ecological measurements and sensors. Next, a synthesis of early NEON science, based on \u3e100 existing publications, funded proposal efforts, and emergent science at the very first NEON Science Summit (hosted by Earth Lab at the University of Colorado Boulder in October 2019) is provided. Key questions that the ecology community will address with NEON data in the next 10 yr are outlined, from understanding drivers of biodiversity across spatial and temporal scales to defining complex feedback mechanisms in human–environmental systems. Last, the essential elements needed to engage and support a diverse and inclusive NEON user community are highlighted: training resources and tools that are openly available, funding for broad community engagement initiatives, and a mechanism to share and advertise those opportunities. NEON users require both the skills to work with NEON data and the ecological or environmental science domain knowledge to understand and interpret them. This paper synthesizes early directions in the community’s use of NEON data, and opportunities for the next 10 yr of NEON operations in emergent science themes, open science best practices, education and training, and community building

Highly sensitive electrochemical sensor for the detection of Shiga toxin-producing E. coli using interdigitated micro-electrodes selectively modified with a chitosan-gold nanocomposite

Shiga toxin-producing E. coli (STEC) is a food-borne pathogen of significant concern due to the severity of the disease it can cause. Herein we report the development of a highly sensitive, label-free, electrochemical DNA-based sensor for detection of stx1 gene using interdigitated gold microelectrodes (IDEs) on fully integrated silicon chips. Each IDE comprised a working IDE, used for DNA probe immobilisation and generator IDE used for accumulation of methylene blue. First, the working IDE was modified with gold nanoparticles (Au NPs) and chitosan gold nanocomposite. Afterwards, amine-modified probe DNA was immobilised on the chitosan modified electrode using glutaraldehyde as a linker. The label-free electrochemical detection was undertaken using methylene blue as a redox molecule, which intercalated into the double-strand DNA after applying an open potential circuit at the generator IDEs. Reduction of methylene blue was recorded using square wave voltammetry (SWV). Using this label-free detection, we have achieved linear response between 10-16 and 10-6 M synthetic target strand with the lowest limit of detection of 100 aM after 20 minutes hybridisation time. The chromosomal DNA from four different E. coli strains (two stx1 positives and two stx1 negatives) was used to confirm the selectivity of the presented method. This novel on-chip biosensor for the detection of STEC has the potential to be used in point-of-use detection, for example, on the farm

Reagent Free Electrochemical-Based Detection of Silver Ions at Interdigitated Micro Electrodes Using in Situ pH Control

Silver ions, the most toxic form of silver, can be present in drinking water due to their release from silver nanoparticles which are widely used in consumer products. Due to their adverse health effects, a quick portable approach for detection in drinking water is needed. Herein we report on the development of an electrochemical sensor for silver ions detection in tap water using linear sweep voltammetry with in situ pH control; enabled by closely space interdigitated electrode arrays. The in situ pH control approach, allows the pH of a test solution to be tailored to pH 3 thereby eliminating the current need for acid addition. A calibration curve between 0.2 - 10 µM was established for silver detection in sodium acetate when 1.25 V and 1.65 V was applied at the protonator electrode during deposition and stripping, respectively, as a proof of concept study. For the final application in tap water, 1.65 V was applied at the protonator electrode during deposition and stripping. The chlorine ions, present in tap water as a consequence of the disinfection process, facilitated the silver detection and no additional electrolyte had to be added. Combination of complexation of silver ions with chlorine coupled with in situ pH control resulted in linear calibration range between 0.25 and 2 µM in tap water without the need for acidification.</p

Amplification-free, highly sensitive electrochemical DNA-based sensor for simultaneous detection of stx1 and stx2 genes of Shiga toxin-producing E. coli (STEC)

Shiga toxin-producing E. coli (STEC) is a food-borne pathogen of significant public health concern, due to the severity of the illness it can cause and a low infection dose. The key targets in molecular-based assays to detect STEC are stx1 or stx2 genes, coding for the ability to produce Shiga T Toxin 1 and 2. The most commonly used molecular detection techniques, such as PCR and real-time PCR, are considerably time-consuming and there is an urgent need for a more rapid screening assay which could be used in agri-food settings. In this work, an amplification-free multiplex electrochemical sensor for the simultaneous detection of stx1 and stx2 genes was developed using a silicon-based chip comprising of six interdigitated gold microelectrodes(IDE) sensors. Two probes complementary to stx1 and stx2 genes were immobilised on a single chip allowing for multiplex detection. The selectivity of the multiplex sensor was confirmed using fluorescence and electrochemistry. The developed assay conditions allowed for an improved limit of detection by three orders of magnitude compared to the previous reports achieving a amplification-free limit of detection of 100 zM (10-19 M) for both, stx1 and stx2 genes. The developed sensor was validated using chromosomal DNA extracted from a bacterial culture containing no virulence genes, stx1 gene only, and both stx1 and stx2. Such multiplex sensor, if combined with on-chip DNA extraction, could revolutionise the point-of-use detection of STEC as well as other pathogens for instance on-farm or in the food industry