Phosphorus (P) is essential for plant growth, but excessive and continuous application of P fertilizers and animal manure has led to the accumulation of "legacy phosphorus" (legacy-P) in soils. While legacy-P presents a potential resource to support future agricultural demands, limited understanding of its chemical forms across different soil types hinders its sustainable management. This study aimed to characterize the chemical nature and storage potential of legacy-P in three contrasting soil types: acidic, organic, and calcareous. Key soil properties—including pH, organic matter, total P, Mehlich-3 P, and concentrations of aluminum (Al), calcium (Ca), iron (Fe), and magnesium (Mg)—were evaluated alongside P fractionation using a modified Hedley method. Furthermore, the soil P saturation ratio (PSR) was calculated to evaluate the relative saturation of soil sorption sites with P. Results showed considerable variability in Mehlich-3 P across soil types, ranging from 7–62

Phosphorus (P) is a finite, essential resource critical for agriculture, yet its unsustainable management through excessive fertilizer application leads to significant environmental degradation, including water pollution. This directly impedes progress towards UN Sustainable Development Goals (SDGs) 2 (Zero Hunger) by wasting resources vital for food security and SDG 6 (Clean Water and Sanitation) by polluting aquatic ecosystems. Here, we develop a reagent-free orthophosphate chemosensor based on a sorbent material containing graphene oxide (GO) and diallyl-dimethylammonium chloride (PolyDADMAC), termed GO-PDDA. Laser-induced graphene electrodes were coated with GO-PDDA material using four different grafting or drop-cast techniques. Electrochemical testing showed that grafted GO-PDDA electrodes were more efficient than drop-cast GO-PDDA or DADMAC grafted electrodes. Developed GO-PDDA sensor is applied for sensing orthophosphate in aqueous samples at pH 7–9. Equivalent circuit modeling indicated that capacitive behavior coincides with Frumkin/Melik-Gaykazyan adsorption theory, where tetrahedral oxyanions increase low-frequency capacitance in thin films. The sensor achieves a detection limit of 20 ± 4 ppb with a rapid 5 min response time, covering concentrations relevant to natural waters. It exhibits high selectivity, being 97% selective for divalent ortho-P over common interferents, 93% over chloride/nitrate, and 87% over sulfate. The chemosensor is reusable, showing less than 5% performance change after regeneration. Validated against EPA Method 365.3 in urban creek water ( R ^2 = 0.92), it offers a faster, reagent-free alternative for direct ortho-P quantification. This work marks the first use of PolyDADMAC as a recognition material in an electrochemical sensor, positioning it as a promising tool for sustainable P management, directly supporting SDG 2, SDG 6, and SDG 12 (Responsible Consumption and Production).

Cost-effectiveness, high-throughput capability, and scalable manufacturing are key features required for the fabrication of in-field electrochemical sensors applicable to food safety analysis. In this work, a two-step method is described to create laser-induced graphene electrodes decorated with nickel oxide nanoparticles (LIG-NiO). Fabrication of the LIG-NiO electrodes is performed via direct writing under ambient conditions using a polyimide sheet and nickel acetate solution as substrates, which is then converted into a label-free immunosensor for the detection of Salmonella enterica serovar Typhimurium by functionalizing the working surface with an anti-Salmonella antibody. The resulting electrochemical immunosensor exhibits a sensitivity of 3.93 ± 0.25 Ω (log (CFU mL−1)−1), a limit of detection (LOD) of 8 ± 3 CFU mL−1 and rapid response time (17 min) with a wide Salmonella Typhimurium linear sensing range, from 101 to 106 CFU mL−1 in buffer, covering relevant levels for food safety analysis without being affected by the presence of interferent bacteria Escherichia coli spp. Additionally, this LIG-NiO-based immunosensor presented a sensitivity of 1.92 ± 0.71 Ω (log (CFU mL−1)−1) when tested in chicken broth. The immunosensor developed in this study provides a simple fabrication method followed by functionalization and rapid Salmonella Typhimurium sensing that does not require sample pretreatment such as pre-enrichment or addition of external reagents, constituting a promising new sensing platform for pathogen detection in food safety monitoring and in general to other electrochemical immunosensing applications.

In a previous Arabidopsis investigation, three ovule-specific cell-wall peroxidases decreased seed abortion rates. These peroxidases were expressed in soybean plants. Because cell wall peroxidases alter extensibility, possible effects on seed size and plant yield were evaluated. Since the effects of these peroxidases in Arabidopsis were dependent on environmental stress, soybean plants were grown in controlled environment greenhouse rooms under four temperature treatments; the daily temperature averages were 26, 30, 34, and 38 °C. In this experiment in vivo oxygen levels during seed growth were 25-fold below ambient, which could affect peroxidase activities. Consequently, soybeans were grown at atmospheric (21%) and elevated (32%) O2 to evaluate peroxidase activities at higher O2. Chambers were maintained at 700 ppm CO2 in an attempt to minimize photorespiration in elevated O2. Individual seed weight decreased with increasing temperature to zero at 38 °C. In elevated O2 rooms, the oxygen concentration in developing seeds increased, but, due to leaf photorespiration, plant biomass and seed yield decreased. Seed size and shelling percentage declined equally with temperature at both O2 concentrations. Expression of all three cell-wall peroxidases reduced seed abortion; however, that did not increase yields at ambient or elevated O2. While O2 concentration is less than 1% in developing seeds, increased O2 levels in seeds were not beneficial for soybean reproduction.

Polymer brushes are tethered nanomaterial surface coatings that have important applications in smart release systems, pollutant degradation technologies, and sensors. Most applications of brushes have been in the medical domain, but there is an exciting opportunity to develop responsive interfaces for sensor applications in food systems. In this review article, we summarize common synthesis approaches as well as general mechanisms for stimulus-response behavior. We discuss emerging opportunities and challenges for polymer brush sensors in detection of six key targets in the food system: VOCs, nutraceuticals and bio-active compounds, pesticides, inorganic phosphates and other food additives, proteins such as allergens, and pathogens. Specific to food systems, major challenges include sample (matrix) complexity, material sustainability for sensor development, scalability of polymer brush synthesis, regulatory approval, and trust/transparency in new automated decision support approaches. Here, we also highlight general opportunities and challenges in polymer brush sensing related to advancing cyber-physical systems via decision support systems based on AI. Rapid sensing is crucial for monitoring systems in the farm-to-fork continuum. Polymer brushes are poised to play a key role in development of advanced interfacial control systems in smart sensor systems, opening new doors toward real time monitoring.

Laser inscribed graphene (LIG) is a versatile material that is commonly used to prepare electrochemical sensors (Moreira et al 2023). This protocol describes the fabrication of a 3-electrode plug-and-play chip system based on LIG. The design is compatible with a female USB-A connector which can be modified for connection to any potentiostat using the protocol here. The complete process requires approximately 60 min to complete, including fabrication of USB-A connector (Fig 1).

Laser-inscribed graphene (LIG) is an emerging material for micro-electronic applications and is being used to develop supercapacitors, soft actuators, triboelectric generators, and sensors. The fabrication technique is simple, yet the batch-to-batch variation of LIG quality is not well documented in the literature. In this study, we conduct experiments to characterize batch-to-batch variation in the manufacturing of LIG electrodes for applications in electrochemical sensing. Numerous batches of 36 LIG electrodes were synthesized using a CO2 laser system on polyimide film. The LIG material was characterized using goniometry, stereomicroscopy, open circuit potentiometry, and cyclic voltammetry. Hydrophobicity and electrochemical screening (cyclic voltammetry) indicate that LIG electrode batch-to-batch variation is less than 5% when using a commercial reference and counter electrode. Metallization of LIG led to a significant increase in peak current and specific capacitance (area between anodic/cathodic curve). However, batch-to-batch variation increased to approximately 30%. Two different platinum electrodeposition techniques were studied, including galvanostatic and frequency-modulated electrodeposition. The study shows that formation of metallized LIG electrodes with high specific capacitance and peak current may come at the expense of high batch variability. This design tradeoff has not been discussed in the literature and is an important consideration if scaling sensor designs for mass use is desired. This study provides important insight into the variation of LIG material properties for scalable development of LIG sensors. Additional studies are needed to understand the underlying mechanism(s) of this variability so that strategies to improve the repeatability may be developed for improving quality control. The dataset from this study is available via an open access repository.

Phosphorus (P) removal from water and recovery into useable forms is a critical component of creating a sustainable P cycle, although mature technologies for P removal and recovery are still lacking. The goal of this paper was to advance the testing of novel materials for P removal and recovery from water by providing guidance on the development of more realistic aqueous matrices used during materials development. Literature reports of “new” materials to remove P from water are often difficult to compare in terms of performance because authors use a myriad of water chemistries containing P concentrations, pH, and competing ions. Moreover, many tests are conducted in simplified matrices that do not reflect conditions in real systems. To address this critical gap, the research herein developed a systematic approach of identifying aqueous matrices relevant to P recovery, including key components in the aqueous matrices having the greatest influence on the mechanisms of P removal with emphasis on phosphate precipitation and phosphate adsorption, and providing guidelines on relevant “recipes” for aqueous solutions for testing novel materials. Key components in the aqueous matrices included hydrogen ion (i.e., pH), multivalent metal cations, and dissolved organic matter due to their influence on phosphate precipitation and adsorption mechanisms. Recipes for buffer solution and synthetic groundwater, surface water, anaerobic digestate, and stored urine are discussed in the context of P removal and recovery processes. Wherein the adoption of standard matrices in other fields have permitted direct comparison of processes or materials, it is anticipated that adoption of relevant aqueous matrix recipes for P removal and recovery will improve the ability to directly compare novel materials and processes.

This protocol describes the fabrication of a LIG dip-and-read orthophosphate sensor based on a 2 dimensional sorbent structure (poly[diallydimethylammonium] chloride, a.k.a, PolyDADAMAC) grafted on graphene oxide (GO) as recognition element. The ortho-P sensor uses electrochemical impedance spectroscopy (EIS) as a transduction technique, and laser-induced graphene electrodes as a transducer platform. The process requires approximately 5 hours (from sensor fabrication to testing)

Laser inscribed graphene (LIG) is a versatile material that is commonly used to prepare electrochemical sensors (Moreira et al 2023). This protocol describes the fabrication of a 3-electrode plug-and-play chip system based on LIG. The design is compatible with a female USB-A connector which can be modified for connection to any potentiostat using the protocol here. The complete process requires approximately 60 min to complete, including fabrication of USB-A connector (Fig 1).

Phosphorus (P) is an essential element for all life forms and a finite resource. P cycle plays a vital role in regulating primary productivity, making it a limiting nutrient for agricultural production and increasing the development of fertilizers through extractive mining. However, excessive P may cause detrimental environmental effects on aquatic and agricultural ecosystems. As a result, there is a pressing need for conservation and management of P loads through analytical techniques to measure P and precisely determine P speciation. Here, we explore a new 2D sorbent structure (GO-PDDA) for sensing orthophosphate in aqueous samples. The sorbent mimics a group of phosphate-binding proteins in nature and is expected to bind orthophosphate in solution. Laser-induced graphene (LIG) was coated with GO-PDDA using a drop-cast method. Electrochemical impedance spectroscopy was used as a transduction technique for electrochemical sensing of orthophosphate (HPO42−) and selectivity assay for chloride, sulfate and nitrate in buffer at pH 8. The analytical sensitivity was estimated to be 347 ± 90.2 Ω/ppm with a limit of detection of 0.32 ± 0.04 ppm. Selectivity assays demonstrate that LIG-GO-PDDA is 95% more selective for ortho-P over sulfate and 80% more selective over chloride and nitrate. The developed sensor can be reused after surface regeneration with an acidic buffer (pH 5), with slight changes in sensor performance. Our results show that the sorbent structure is a promising candidate for developing electrochemical sensors for environmental monitoring of orthophosphate and may provide reliable data to support sustainable P management.

AbstractConsumption of fresh produce, such as leafy greens, is often encouraged as part of a healthy diet. Hence, indoor facilities for hydroponic production of leafy greens are increasingly being established. However, fresh produce entails a higher risk of microbial foodborne illnesses than processed foods. Listeria monocytogenes is a major source of fresh produce contamination and is among the leading causes of severe foodborne illnesses in the United States, with a 16% mortality rate. Tools for rapid monitoring are needed for pathogens such as L. monocytogenes to prevent outbreaks. In this manuscript, we have demonstrated the feasibility of a multi-aptamer approach for development of label-free aptasensors targeting L. monocytogenes in irrigation water for lettuce hydroponic production. We use screening studies with surface plasmon resonance to rationally develop mixtures of relevant aptamers for targeting L. monocytogenes. Based on this screening, multiple aptamers targeting extracellular structures on intact L. monocytogenes were tethered to platinum-modified laser inscribed graphene electrodes. This is the first report of a L. monocytogenes biosensor based on laser inscribed graphene. We show that mixing multiple aptamers with varying affinity improves the diagnostic performance over one aptamer alone in complex sample matrices (lettuce hydroponic water). Multi-aptamer biosensors showed high accuracy for L. monocytogenes and were at least three times more selective than Escherichia coli (Crooks, K12, O157:H7) with an accuracy of 85%. The limit of detection (10 CFU/10 mL) is based on data which were significantly different after calibration toward L. monocytogenes or E. coli (Crooks) and validated against gold standard molecular analysis (polymerase chain reaction). Rapid screening of pathogens is a global need to meet food safety and water quality regulations. This study shows the importance of sensors targeting more than one bacterial surface structure in complex samples relevant to the food-water nexus.

The increasing demand for sustainable food production has driven a surge in the use and commercialization of biological inputs, including biofertilizers. In this context, biofertilizers offer potential benefits for nutrient use efficiency, crop yield and sustainability. However, inconsistent definition of the term “biofertilizer” and regulations, particularly in the USA, hinder market growth and consumer confidence. While the European Union, and countries like Brazil, India, and China have made progress in this area, the USA market, projected to exceed 1 billion by 2029, lacks clear guidelines for biofertilizer production and sale. The USA market is dominated by Rhizobium genus, Mycorrhizae fungi, and Azospirillum species and based products targeting various crops. Although there is a growing and promising market for the use of biofertilizers, there are still many challenges to overcome, and to fully realize the potential of biofertilizers, future research should focus on modes of action, specific claims, and robust regulations that must be established. • The term “biofertilizer” lacks a universally accepted definition • It is necessary establishing a national regulation for biofertilizers in the USA • The biofertilizer market is growing fast and the biggest one is in America

Phosphorus (P) is essential for growing crops, but the supply of high-quality phosphate rock reserves used for fertilizer production is finite while losses of P from the food/waste system cause considerable environmental damage. A variety of emerging approaches in biotechnology are reviewed that hold promise for improving the sustainability of P use in the food/water systems. These include improved sensors, cell culture approaches to meat production, bio-based P adsorption and transformation strategies, advancements in understanding of polyphosphate-accumulating organisms, and new approaches involving biomineralization and anaerobic treatment. By advancing these technologies to scale, progress can be made in developing a circular phosphorus economy that improves food security while protecting drinking water and aquatic ecosystems.

This protocol describes the synthesis of aligned carbon nano fiber for adsorbent/photocatalyst inenvironmental samples, electrochemical energy storage and other industrialapplications. The steps for the process are based on Zeng et al 1 summarized in Figure 1.

This review illuminates established knowledge of root–arbuscular mycorrhizal fungi (AMF)–plant mutualism to study the uptake of phosphorus (P) as a critical element for plant nutrition. We focus on P cycling, underscoring the role of AMF in enhancing P acquisition and plant resilience in the rhizosphere. The role(s) of plant roots, root exudates, and biomolecules in relevant soil processes is emphasized in this manuscript. Enhancing P uptake efficiency through AMF interaction presents a promising avenue for sustainable agriculture, with future research opportunities focusing on understanding underlying mechanisms and developing innovative technologies as a need to transition from the use of AMF as a biofertilizer or as an inoculation alternative for seeds to being an inspiration for the development of technology adapted to different crops. This is important to promote responsible agricultural practices and improve crop yields. We provide definitions of key terms and concepts for one of the best-known natural sustainable phosphorus systems. This manuscript illuminates and aims to inspire technology development to overcome the challenge of plant nutrition under P scarcity conditions.

This protocol describes activities used in summer education camps for youth (14 years and older). The activities involve extraction and cryo-concentration of plant pigment (anthocyanin) from red cabbage. This protocol describes summer camp activities for encapsulation/spherification in alginate beads and other alternative methods for teaching basic principles related to cross linking and colorimetry.

Laser-inscribed graphene (LIG), initially developed for graphene supercapacitors, has found widespread use in sensor research and development, particularly as a platform for low-cost electrochemical sensing. However, batch-to-batch variation in LIG fabrication introduces uncertainty that cannot be adequately tracked during manufacturing process, limiting scalability. Therefore, there is an urgent need for robust quality control (QC) methodologies to identify and select similar and functional LIG electrodes for sensor fabrication. For the first time, we have developed a statistical workflow and an open-source hierarchical clustering tool for QC analysis in LIG electrode fabrication. The QC process was challenged with multi-operator cyclic voltammetry (CV) data for bare and metalized LIG. As a proof of concept, we employed the developed QC process for laboratory-scale manufacturing of LIG-based biosensors. The study demonstrates that our QC process can rapidly identify similar LIG electrodes from large batches (n ≥ 36) of electrodes, leading to a reduction in biosensor measurement variation by approximately 13% compared to the control group without QC. The statistical workflow and open-source code presented here provide a versatile toolkit for clustering analysis, opening a pathway toward scalable manufacturing of LIG electrodes in sensing. In addition, we establish a data repository for further study of LIG variation.