Nanobiotechnology approaches for engineering smart plant sensors

Peptide-mediated Targeting of Nanoparticles with Chemical Cargoes to Chloroplasts in Arabidopsis Plants

Plant nanobiotechnology is a flourishing field that uses nanomaterials to study and engineer plant function. Applications of nanotechnology in plants have great potential as tools for improving crop yield, tolerance to disease and environmental stress, agrochemical delivery of pesticides and fertilizers, and genetic modification and transformation of crop plants. Previous studies have used nanomaterials functionalized with chemicals, including biocompatible polymers with charged, neutral, or hydrophobic functional groups, to improve nanomaterial uptake and localization in plant cells. Recently, the use of biorecognition motifs such as peptides has been demonstrated to enable the targeted delivery of nanoparticles in plants ( Santana et al., 2020 ). Herein, we describe a bio-protocol to target nanoparticles with chemical cargoes to chloroplasts in plant leaves and assess targeting efficiency using advanced analytical tools, including confocal microscopy and elemental analysis. We also describe the use of isothermal titration calorimetry to determine the affinity of nanomaterials for their chemical cargoes. Nanotechnology-based methods for targeted delivery guided by conserved plant molecular recognition mechanisms will provide more robust plant bioengineering tools across diverse plant species. Graphic abstract: Targeted delivery of nanomaterials with chemical cargoes to chloroplasts enabled by plant biorecognition.

Environmental dimensions of the protein corona

The adsorption of biomolecules to the surface of engineered nanomaterials, known as corona formation, defines their biological identity by altering their surface properties and transforming the physical, chemical and biological characteristics of the particles. In the first decade since the term protein corona was coined, studies have focused primarily on biomedical applications and human toxicity. The relevance of the environmental dimensions of the protein corona is still emerging. Often referred to as the eco-corona, a biomolecular coating forms upon nanomaterials as they enter the environment and may include proteins, as well as a diverse array of other biomolecules such as metabolites from cellular activity and/or natural organic matter. Proteins remain central in studies of eco-coronas because of the ease of monitoring and structurally characterizing proteins, as well as their crucial role in receptor engagement and signalling. The proteins within the eco-corona are optimal targets to establish the biophysicochemical principles of corona formation and transformation, as well as downstream impacts on nanomaterial uptake, distribution and impacts on the environment. Moreover, proteins appear to impart a biological identity, leading to cellular or organismal recognition of nanomaterials, a unique characteristic compared with natural organic matter. We contrast insights into protein corona formation from clinical samples with those in environmentally relevant systems. Principles specific to the environment are also explored to gain insights into the dynamics of interaction with or replacement by other biomolecules, including changes during trophic transfer and ecotoxicity. With many challenges remaining, we also highlight key opportunities for method development and impactful systems on which to focus the next phase of eco-corona studies. By interrogating these environmental dimensions of the protein corona, we offer a perspective on how mechanistic insights into protein coronas in the environment can lead to more sustainable, environmentally safe nanomaterials, as well as enhancing the efficacy of nanomaterials used in remediation and in the agri-food sector.

Advantage of Nanotechnology-Based Genome Editing System and Its Application in Crop Improvement

Agriculture is an important source of human food. However, current agricultural practices need modernizing and strengthening to fulfill the increasing food requirements of the growing worldwide population. Genome editing (GE) technology has been used to produce plants with improved yields and nutritional value as well as with higher resilience to herbicides, insects, and diseases. Several GE tools have been developed recently, including clustered regularly interspaced short palindromic repeats (CRISPR) with nucleases, a customizable and successful method. The main steps of the GE process involve introducing transgenes or CRISPR into plants via specific gene delivery systems. However, GE tools have certain limitations, including time-consuming and complicated protocols, potential tissue damage, DNA incorporation in the host genome, and low transformation efficiency. To overcome these issues, nanotechnology has emerged as a groundbreaking and modern technique. Nanoparticle-mediated gene delivery is superior to conventional biomolecular approaches because it enhances the transformation efficiency for both temporal (transient) and permanent (stable) genetic modifications in various plant species. However, with the discoveries of various advanced technologies, certain challenges in developing a short-term breeding strategy in plants remain. Thus, in this review, nanobased delivery systems and plant genetic engineering challenges are discussed in detail. Moreover, we have suggested an effective method to hasten crop improvement programs by combining current technologies, such as speed breeding and CRISPR/Cas, with nanotechnology. The overall aim of this review is to provide a detailed overview of nanotechnology-based CRISPR techniques for plant transformation and suggest applications for possible crop enhancement.

Cohabiting Plant-Wearable Sensor In Situ Monitors Water Transport in Plant

The boom of plant phenotype highlights the need to measure the physiological characteristics of an individual plant. However, continuous real-time monitoring of a plant's internal physiological status remains challenging using traditional silicon-based sensor technology, due to the fundamental mismatch between rigid sensors and soft and curved plant surfaces. Here, the first flexible electronic sensing device is reported that can harmlessly cohabitate with the plant and continuously monitor its stem sap flow, a critical plant physiological characteristic for analyzing plant health, water consumption, and nutrient distribution. Due to a special design and the materials chosen, the realized plant-wearable sensor is thin, soft, lightweight, air/water/light-permeable, and shows excellent biocompatibility, therefore enabling the sap flow detection in a continuous and non-destructive manner. The sensor can serve as a noninvasive, high-throughput, low-cost toolbox, and holds excellent potentials in phenotyping. Furthermore, the real-time investigation on stem flow insides watermelon reveals a previously unknown day/night shift pattern of water allocation between fruit and its adjacent branch, which has not been reported before.

Wireless Self-Powered High-Performance Integrated Nanostructured-Gas-Sensor Network for Future Smart Homes

The accelerated evolution of communication platforms including Internet of Things (IoT) and the fifth generation (5G) wireless communication network makes it possible to build intelligent gas sensor networks for real-time monitoring chemical safety and personal health. However, this application scenario requires a challenging combination of characteristics of gas sensors including small formfactor, low cost, ultralow power consumption, superior sensitivity, and high intelligence. Herein, self-powered integrated nanostructured-gas-sensor (SINGOR) systems and a wirelessly connected SINGOR network are demonstrated here. The room-temperature operated SINGOR system can be self-driven by indoor light with a Si solar cell, and it features ultrahigh sensitivity to H₂, formaldehyde, toluene, and acetone with the record low limits of detection (LOD) of 10, 2, 1, and 1 ppb, respectively. Each SINGOR consisting of an array of nanostructured sensors has the capability of gas pattern recognition and classification. Furthermore, multiple SINGOR systems are wirelessly connected as a sensor network, which has successfully demonstrated flammable gas leakage detection and alarm function. They can also achieve gas leakage localization with satisfactory precision when deployed in one single room. These successes promote the development of using nanostructured-gas-sensor network for wide range applications including smart home/building and future smart city.

Recent Advances in the Fabrication and Functionalization of Flexible Optical Biosensors: Toward Smart Life-Sciences Applications

Over the last 30 years, optical biosensors based on nanostructured materials have obtained increasing interest since they allow the screening of a wide variety of biomolecules with high specificity, low limits of detection, and great sensitivity. Among them, flexible optical platforms have the advantage of adapting to non-planar surfaces, suitable for in vivo and real-time monitoring of diseases and assessment of food safety. In this review, we summarize the newest and most advanced platforms coupling optically active materials (noble metal nanoparticles) and flexible substrates giving rise to hybrid nanomaterials and/or nanocomposites, whose performances are comparable to the ones obtained with hard substrates (e.g., glass and semiconductors). We focus on localized surface plasmon resonance (LSPR)-based and surface-enhanced Raman spectroscopy (SERS)-based biosensors. We show that large-scale, cost-effective plasmonic platforms can be realized with the currently available techniques and we emphasize the open issues associated with this topic.

Stress Response and Nutrient Homeostasis in Lettuce (Lactuca sativa) Exposed to Graphene Quantum Dots Are Modulated by Particle Surface Functionalization

A 5-d germination assay and a 14-d hydroponic trial are performed to evaluate the impacts of graphene quantum dots (GQDs) on lettuce. Results show that GQDs are toxic to lettuce plants and that the effects are highly dependent on particle surface functionalization and plant growth stage. The germination rate is not affected by aminated GQDs (N-GQDs) and carboxylated GQDs (C-GQDs) but is reduced by hydroxylated GQDs (O-GQDs) by 39-71%. During the hydroponic trial, N-GQDs (50 mg L-1 ) increase the root dry weight by 34%, while C-GQDs and O-GQDs reduce it by 39% and 43%, respectively. Shoot dry weight is not affected by N-GQDs but is reduced by C-GQDs (44%) and O-GQDs (36-55%) treatments. C-GQDs and O-GQDs cause oxidative damage, disruption of mineral and organic nutrients homeostasis, impairment of photosynthesis, and modulates the levels of phytohormones. Light-triggered reactive oxygen species generation and oxidation of antioxidants in plants are the critical reason for the phytotoxicity and explain the difference between the different functionalizations. These findings suggest that GQDs may not be as safe as expected. Future studies should consider the modulation of surface chemistry to achieve optimal safety of GQDs, and more plant species should be tested over a longer-term scale.

Graphitic Carbon Nitride (C3N4) Reduces Cadmium and Arsenic Phytotoxicity and Accumulation in Rice (Oryza sativa L.)

The present study investigated the role of graphitic carbon nitride (C₃N₄) in alleviating cadmium (Cd)- and arsenic (As)-induced phytotoxicity to rice (Oryza sativa L.). A high-temperature pyrolysis was used to synthesize the C₃N₄, which was characterized by transmission electron microscopy, Fourier-transform infrared spectroscopy, and dynamic light scattering. Rice seedlings were exposed to C₃N₄ at 50 and 250 mg/L in half-strength Hoagland’s solution amended with or without 10 mg/L Cd or As for 14 days. Both Cd and As alone resulted in 26–38% and 49–56% decreases in rice root and shoot biomass, respectively. Exposure to 250 mg/L C₃N₄ alone increased the root and shoot fresh biomass by 17.5% and 25.9%, respectively. Upon coexposure, Cd + C₃N₄ and As + C₃N₄ alleviated the heavy metal-induced phytotoxicity and increased the fresh weight by 26–38% and 49–56%, respectively. Further, the addition of C₃N₄ decreased Cd and As accumulation in the roots by 32% and 25%, respectively, whereas the metal contents in the shoots were 30% lower in the presence of C₃N₄. Both As and Cd also significantly altered the macronutrient (K, P, Ca, S, and Mg) and micronutrient (Cu, Fe, Zn, and Mn) contents in rice, but these alterations were not evident in plants coexposed to C₃N₄. Random amplified polymorphic DNA analysis suggests that Cd significantly altered the genomic DNA of rice roots, while no difference was found in shoots. The presence of C₃N₄ controlled Cd and As uptake in rice by regulating transport-related genes. For example, the relative expression of the Cd transporter OsIRT1 in roots was upregulated by approximately threefold with metal exposure, but C₃N₄ coamendment lowered the expression. Similar results were evident in the expression of the As transporter OsNIP1;1 in roots. Overall, these findings facilitate the understanding of the underlying mechanisms by which carbon-based nanomaterials alleviate contaminant-induced phyto- and genotoxicity and may provide a new strategy for the reduction of heavy metal contamination in agriculture.

Breathable Nanogenerators for an On-Plant Self-Powered Sustainable Agriculture System

Building an intelligent interface between plants and the environment is of paramount importance for real-time monitoring of the health status of plants, especially promising for high agricultural yield. Although the advancement of various sensors allows automated monitoring, developing a sustainable power supply for these electronic devices remains a formidable challenge. Herein, a waterproof and breathable triboelectric nanogenerator (WB-TENG) is designed based on poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) nanofibers embedded with fluorinated carbon nanotubes (F-CNT) microspheres, which was realized by simultaneous electrospinning and electrospraying, respectively. Using carbon nanotubes (CNT) as the electrode, the WB-TENG shows micro-to-nano hierarchical porous structures and high electrostatic adhesion, exhibiting a high output power density of 330.6 μW cm^-2, breathability, and hydrophobicity. Besides, the WB-TENG can be conformally self-attached to plant leaves without sacrificing the intrinsic physiological activities of plants, capable of harvesting typical environmental energy from wind and raindrops. Results demonstrate that the WB-TENG can serve as a sustainable power supply for a wireless plant sensor, enabling real-time monitoring of the health status of plants. This work realizes the concept of constructing a plant compatible TENG with environment adaptivity and energy scavenging ability, showing great potential in building a self-powered agriculture system.

Emerging Technologies for Monitoring Plant Health in Vivo

In the coming decades, increasing agricultural productivity is all-important. As the global population is growing rapidly and putting increased demand on food supply, poor soil quality, drought, flooding, increasing temperatures, and novel plant diseases are negatively impacting yields worldwide. One method to increase yields is plant health monitoring and rapid detection of disease, nutrient deficiencies, or drought. Monitoring plant health will allow for precise application of agrichemicals, fertilizers, and water in order to maximize yields. In vivo plant sensors are an emerging technology with the potential to increase agricultural productivity. In this mini-review, we discuss three major approaches of in vivo sensors for plant health monitoring, including genetic engineering, imaging and spectroscopy, and electrical.

Highly stable Pd/HNb3O8-based flexible humidity sensor for perdurable wireless wearable applications

Real-time, daily health monitoring can provide large amounts of patient data, which may greatly improve the likelihood of diagnosing health conditions at an early stage. One potential sensor is a flexible humidity sensor to monitor moisture and humidity information such as dehydration. However, achieving a durable functional nanomaterial-based flexible humidity sensor remains a challenge due to partial desorption of water molecules during the recovery process, especially at high humidities. In this work, we demonstrate a highly stable resistive-type Pd/HNb₃O₈ humidity sensor, which exhibits a perdurable performance for over 100 h of cycle tests under a 90% relative humidity (RH) without significant performance degradation. One notable advantage of the Pd/HNb₃O₈ humidity sensor is its ability to regulate hydroniums due to the strong reducibility of H atoms dissociated on the Pd surface. This feature realizes a high stability even at a high humidity (99.9% RH). Using this superior performance, the Pd/HNb₃O₈ humidity sensor realizes wireless monitoring of the changes in the fingertip humidity of an adult under different physiological states, demonstrating a facile and reliable path for dehydration diagnosis.

Challenges and potential solutions for nanosensors intended for use with foods

Nanotechnology-adapted detection technologies could improve the safety and quality of foods, provide new methods to combat fraud and be useful tools in our arsenal against bioterrorism. Yet despite hundreds of published studies on nanosensors each year targeted to the food and agriculture space, there are few nanosensors on the market in this area and almost no nanotechnology-enabled methods employed by public health agencies for food analysis. This Review shows that the field is currently being held back by technical, regulatory, political, legal, economic, environmental health and safety, and ethical challenges. We explore these challenges in detail and provide suggestions about how they may be surmounted. Strategies that may have particular effectiveness include improving funding opportunities and publication venues for nanosensor validation, social science and patent landscape studies; prioritizing research and development of nanosensors that are specifically designed for rapid analysis in non-laboratory settings; and incorporating platform cost and adaptability into early design decisions.

Nitric oxide signalling in plant nanobiology: current status and perspectives

Plant nanobiology as a novel research field provides a scientific basis for the agricultural use of nanoparticles (NPs). Plants respond to the presence of nanomaterials by synthesizing signal molecules, such as the multifunctional gaseous nitric oxide (NO). Several reports have described the effects of different nanomaterials (primarily chitosan NPs, metal oxide NPs, and carbon nanotubes) on endogenous NO synthesis and signalling in different plant species. Other works have demonstrated the ameliorating effect of exogenous NO donor (primarily sodium nitroprusside) treatments on NP-induced stress. NO-releasing NPs are preferred alternatives to chemical NO donors, and evaluating their effects on plants has recently begun. Previous studies clearly indicate that endogenous NO production in the presence of nanomaterials or NO levels increased by exogenous treatments (NO-releasing NPs or chemical NO donors) exerts growth-promoting and stress-ameliorating effects in plants. Furthermore, an NP-based nanosensor for NO detection in plants has been developed, providing a new and excellent perspective for basic research and also for the evaluation of plants' health status in agriculture.

Towards a point-of-care SERS sensor for biomedical and agri-food analysis applications: a review of recent advancements

The growing demand for reliable and robust methodology in bio-chemical sensing calls for the continuous advancement of sensor technologies. Over the last two decades, surface-enhanced Raman spectroscopy (SERS) has emerged as one of the most promising analytical techniques for sensitive and trace analysis or detection in biomedical and agri-food applications. SERS overcomes the inherent sensitivity limitation associated with Raman spectroscopy, which provides vibrational "fingerprint" spectra of molecules that makes it unique and versatile among other spectroscopy techniques. This paper comprehensively reviews the recent advancements of SERS for biomedical, food and agricultural applications over the last 6 years, and we envision that, in the near future, some of these platforms have the potential to be translated as a point-of-care and rapid sensor for real-life end-user applications. The merits and limitations of various SERS sensor designs are analysed and discussed based on critical features such as sensitivity, specificity, usability, repeatability and reproducibility. We conclude by highlighting the opportunities and challenges in the field while stressing the technological gaps to be addressed in realizing commercially viable point-of-care SERS sensors for practical biomedical and agri-food technological applications.

Boron: More Than an Essential Element for Land Plants?

Although boron (B) is an element that has long been assumed to be an essential plant micronutrient, this assumption has been recently questioned. Cumulative evidence has demonstrated that the players associated with B uptake and translocation by plant roots include a sophisticated set of proteins used to cope with B levels in the soil solution. Here, we summarize compelling evidence supporting the essential role of B in mediating plant developmental programs. Overall, most plant species studied to date have exhibited specific B transporters with tight genetic coordination in response to B levels in the soil. These transporters can uptake B from the soil, which is a highly uncommon occurrence for toxic elements. Moreover, the current tools available to determine B levels cannot precisely determine B translocation dynamics. We posit that B plays a key role in plant metabolic activities. Its importance in the regulation of development of the root and shoot meristem is associated with plant developmental phase transitions, which are crucial processes in the completion of their life cycle. We provide further evidence that plants need to acquire sufficient amounts of B while protecting themselves from its toxic effects. Thus, the development of in vitro and in vivo approaches is required to accurately determine B levels, and subsequently, to define unambiguously the function of B in terrestrial plants.

Applications of nanobodies in plant science and biotechnology

Present review summarizes the current applications of nanobodies in plant science and biotechnology, including plant expression of nanobodies, plant biotechnological applications, nanobody-based immunodetection, and nanobody-mediated resistance against plant pathogens. Nanobodies (Nbs) are variable domains of heavy chain-only antibodies (HCAbs) isolated from camelids. In spite of their single domain structure, nanobodies display many unique features, such as small size, high stability, and cryptic epitopes accessibility, which make them ideal for sophisticated applications in plants and animals. In this review, we summarize the current applications of nanobodies in plant science and biotechnology, focusing on nanobody expression in plants, plant biotechnological applications, determination of plant toxins and pathogens, and nanobody-mediated resistance against plant pathogens. Prospects and challenges of nanobody applications in plants are also discussed.

Towards safe and sustainable innovation in nanotechnology: State-of-play for smart nanomaterials

The European Green Deal, the European Commission's new Action Plan for a Circular Economy, the new European Industrial Strategy and the Chemicals Strategy for Sustainability launched in October 2020 are ambitious plans to achieve a sustainable, fair and inclusive European Union's economy. In line with the United Nations Sustainable Development Goals 2030, these policies require that any new material or product should be not only functional and cost-effective but also safe and sustainable to ensure compliance with regulation and acceptance by consumers. Nanotechnology is one of the technologies that could enable such a green growth. This paper focuses on advanced nanomaterials that actively respond to external stimuli, also known as 'smart nanomaterials', and which are already on the market or in the research and development phase for non-medical applications such as in agriculture, food, food packaging and cosmetics. A review shows that smart nanomaterials and enabled products may present new challenges for safety and sustainability assessment due to their complexity and dynamic behaviour. Moreover, existing regulatory frameworks, in particular in the European Union, are probably not fully prepared to address them. What is missing today is a systematic and comprehensive approach that allows for considering sustainability aspects hand in hand with safety considerations very early on at the material design stage. We call on innovators, scientists and authorities to further develop and promote the 'Safe- and Sustainable-by-Design' concept in nanotechnology and propose some initiatives to go into this direction.

Nanotechnology Approaches for Chloroplast Biotechnology Advancements

Photosynthetic organisms are sources of sustainable foods, renewable biofuels, novel biopharmaceuticals, and next-generation biomaterials essential for modern society. Efforts to improve the yield, variety, and sustainability of products dependent on chloroplasts are limited by the need for biotechnological approaches for high-throughput chloroplast transformation, monitoring chloroplast function, and engineering photosynthesis across diverse plant species. The use of nanotechnology has emerged as a novel approach to overcome some of these limitations. Nanotechnology is enabling advances in the targeted delivery of chemicals and genetic elements to chloroplasts, nanosensors for chloroplast biomolecules, and nanotherapeutics for enhancing chloroplast performance. Nanotechnology-mediated delivery of DNA to the chloroplast has the potential to revolutionize chloroplast synthetic biology by allowing transgenes, or even synthesized DNA libraries, to be delivered to a variety of photosynthetic species. Crop yield improvements could be enabled by nanomaterials that enhance photosynthesis, increase tolerance to stresses, and act as nanosensors for biomolecules associated with chloroplast function. Engineering isolated chloroplasts through nanotechnology and synthetic biology approaches are leading to a new generation of plant-based biomaterials able to self-repair using abundant CO₂ and water sources and are powered by renewable sunlight energy. Current knowledge gaps of nanotechnology-enabled approaches for chloroplast biotechnology include precise mechanisms for entry into plant cells and organelles, limited understanding about nanoparticle-based chloroplast transformations, and the translation of lab-based nanotechnology tools to the agricultural field with crop plants. Future research in chloroplast biotechnology mediated by the merging of synthetic biology and nanotechnology approaches can yield tools for precise control and monitoring of chloroplast function in vivo and ex vivo across diverse plant species, allowing increased plant productivity and turning plants into widely available sustainable technologies.

Nanoparticle-Based Sustainable Agriculture and Food Science: Recent Advances and Future Outlook

In the current scenario, it is an urgent requirement to satisfy the nutritional demands of the rapidly growing global population. Using conventional farming, nearly one third of crops get damaged, mainly due to pest infestation, microbial attacks, natural disasters, poor soil quality, and lesser nutrient availability. More innovative technologies are immediately required to overcome these issues. In this regard, nanotechnology has contributed to the agrotechnological revolution that has imminent potential to reform the resilient agricultural system while promising food security. Therefore, nanoparticles are becoming a new-age material to transform modern agricultural practices. The variety of nanoparticle-based formulations, including nano-sized pesticides, herbicides, fungicides, fertilizers, and sensors, have been widely investigated for plant health management and soil improvement. In-depth understanding of plant and nanomaterial interactions opens new avenues toward improving crop practices through increased properties such as disease resistance, crop yield, and nutrient utilization. In this review, we highlight the critical points to address current nanotechnology-based agricultural research that could benefit productivity and food security in future.

Species-independent analytical tools for next-generation agriculture

Innovative approaches are urgently required to alleviate the growing pressure on agriculture to meet the rising demand for food. A key challenge for plant biology is to bridge the notable knowledge gap between our detailed understanding of model plants grown under laboratory conditions and the agriculturally important crops cultivated in fields or production facilities. This Perspective highlights the recent development of new analytical tools that are rapid and non-destructive and provide tissue-, cell- or organelle-specific information on living plants in real time, with the potential to extend across multiple species in field applications. We evaluate the utility of engineered plant nanosensors and portable Raman spectroscopy to detect biotic and abiotic stresses, monitor plant hormonal signalling as well as characterize the soil, phytobiome and crop health in a non- or minimally invasive manner. We propose leveraging these tools to bridge the aforementioned fundamental gap with new synthesis and integration of expertise from plant biology, engineering and data science. Lastly, we assess the economic potential and discuss implementation strategies that will ensure the acceptance and successful integration of these modern tools in future farming practices in traditional as well as urban agriculture.

Seed Biofortification by Engineered Nanomaterials: A Pathway To Alleviate Malnutrition?

Micronutrient deficiencies in global food chains are a significant cause of ill health around the world, particularly in developing countries. Agriculture is the primary source of nutrients required for sound health, and as the population has continued to grow, the agricultural sector has come under pressure to improve crop production, in terms of both quantity and quality, to meet the global demands for food security. The use of engineered nanomaterial (ENM) has emerged as a promising technology to sustainably improve the efficiency of current agricultural practices as well as overall crop productivity. One promising approach that has begun to receive attention is to use ENM as seed treatments to biofortify agricultural crop production and quality. This review highlights the current state of the science for this approach as well as critical knowledge gaps and research needs that must be overcome to optimize the sustainable application of nano-enabled seed fortification approaches.

Unveiling the Synergistic Role of Oxygen Functional Groups in the Graphene-Mediated Oxidation of Glutathione

This is the first report of an atomic-scale direct oxidation mechanism of the thiol group in glutathione (GSH) by epoxides on graphene oxide (GO) at room temperature. The proposed reaction mechanism is determined using a coupled experimental and computational approach; active sites for the reaction are determined through examination of GO surface chemistry changes before and after exposure to GSH, and density functional theory (DFT) calculations determine the reaction barriers for the possible GO-GSH reaction schemes. The findings build on the previously established catalytic mechanism of GSH oxidation by graphenic nanocarbon surfaces and importantly identify the direct reaction mechanism which becomes important in low-oxygen environments. Experimental results suggest epoxides as the active sites for the reaction with GSH, which we confirm using DFT calculations of reaction barriers and further identify a synergism between the adjacent epoxide and hydroxyl groups on the GO surface. The direct oxidation mechanism at specific oxygen sites offers insight into controlling GO chemical reactivity through surface chemistry manipulations. This insight is critical for furthering our understanding of GO oxidative stress pathways in cytotoxicity as well as for providing rational material design for GO applications that can leverage this reaction.

Zinc-Based Nanomaterials for Diagnosis and Management of Plant Diseases: Ecological Safety and Future Prospects

A facet of nanorenaissance in plant pathology hailed the research on the development and application of nanoformulations or nanoproducts for the effective management of phytopathogens deterring the growth and yield of plants and thus the overall crop productivity. Zinc nanomaterials represent a versatile class of nanoproducts and nanoenabled devices as these nanomaterials can be synthesized in quantum amounts through economically affordable processes/approaches. Further, these nanomaterials exhibit potential targeted antimicrobial properties and low to negligible phytotoxicity activities that well-qualify them to be applied directly or in a deviant manner to accomplish significant antibacterial, antimycotic, antiviral, and antitoxigenic activities against diverse phytopathogens causing plant diseases. The photo-catalytic, fluorescent, and electron generating aspects associated with zinc nanomaterials have been utilized for the development of sensor systems (optical and electrochemical biosensors), enabling quick, early, sensitive, and on-field assessment or quantification of the test phytopathogen. However, the proficient use of Zn-derived nanomaterials in the management of plant pathogenic diseases as nanopesticides and on-field sensor system demands that the associated eco- and biosafety concerns should be well discerned and effectively sorted beforehand. Current and possible utilization of zinc-based nanostructures in plant disease diagnosis and management and their safety in the agroecosystem is highlighted.

Chirality-Enriched Carbon Nanotubes for Next-Generation Computing

For the past half century, silicon has served as the primary material platform for integrated circuit technology. However, the recent proliferation of nontraditional electronics, such as wearables, embedded systems, and low-power portable devices, has led to increasingly complex mechanical and electrical performance requirements. Among emerging electronic materials, single-walled carbon nanotubes (SWCNTs) are promising candidates for next-generation computing as a result of their superlative electrical, optical, and mechanical properties. Moreover, their chirality-dependent properties enable a wide range of emerging electronic applications including sub-10 nm complementary field-effect transistors, optoelectronic integrated circuits, and enantiomer-recognition sensors. Here, recent progress in SWCNT-based computing devices is reviewed, with an emphasis on the relationship between chirality enrichment and electronic functionality. In particular, after highlighting chirality-dependent SWCNT properties and chirality enrichment methods, the range of computing applications that have been demonstrated using chirality-enriched SWCNTs are summarized. By identifying remaining challenges and opportunities, this work provides a roadmap for next-generation SWCNT-based computing.

Hydroprinted Liquid-Alloy-Based Morphing Electronics for Fast-Growing/Tender Plants: From Physiology Monitoring to Habit Manipulation

Monitoring physiological signals and manipulating growth habits of living plants in real time are important for botany research, biohybrid plant robots, and precision agriculture. Although emerging epidermal electronics that can conveniently acquire vital signals of living organisms exhibit a high potential for such scenarios, it is a significant challenge to adapt such devices for plants, because they are fragile and usually have complex surfaces that can change significantly during rapid growth. A gentle fabrication process is critical in order to employ compliant electronic systems to adapt to this highly dynamic situation. In this study, a hydroprinted liquid-alloy-based morphing electronics (LAME) process is employed for fast-growing plants that will sense physiological signals and even function as a biohybrid to determine plant behavior on demand. Besides various surfaces of inorganic targeting substrates, pinning liquid alloy circuits onto the complex plant epidermis is enhanced by introducing high-surface-energy liquid. Functionally, the new developed LAME can be used to monitor leaf moisture content and length, and manipulate leaf and bean sprout orientation. This study lays the foundation for a new form of morphing electronics for botany or biohybrid plant robots, potentially impacting the next generation of precision agriculture and smart hybrid robots.

Multimodal Plant Healthcare Flexible Sensor System

The rising global human population and increased environmental stresses require a higher plant productivity while balancing the ecosystem using advanced nanoelectronic technologies. Although multifunctional wearable devices have played distinct roles in human healthcare monitoring and disease diagnosis, probing potential physiological health issues in plants poses a formidable challenge due to their biological complexity. Herein an integrated multimodal flexible sensor system is proposed for plant growth management using stacked ZnIn₂S₄(ZIS) nanosheets as the kernel sensing media. The proposed ZIS-based flexible sensor can not only perceive light illumination at a fast response (∼4 ms) but also monitor the humidity with a perdurable steady performance that has yet to be reported elsewhere. First-principles calculations reveal that the tunneling effect dominates the current model associated with humidity response. This finding guides the investigation on the plant stomatal functions by measuring plant transpiration. Significantly, dehydration conditions are visually recorded during a monitoring period (>15 days). This work may contribute to plant-machine biointerfaces to precisely manage plant health status and judiciously utilize limited resources.

Metal-Organic Framework-Plant Nanobiohybrids as Living Sensors for On-Site Environmental Pollutant Detection

Photoluminescent metal-organic frameworks (MOFs) were grown in a living plant (Syngonium podophyllum) via immersing their roots in an aqueous solution of disodium terephthalate and terbium chloride hexahydrate sequentially for 12 h without affecting their viability. Then, app-assisted living MOF-plant nanobiohybrids were used for the detection of various toxic metal ions and organic pollutants. Their performance and sensing mechanism were also evaluated. The results demonstrated that the living plants served as self-powered preconcentrators via their passive fluid transport systems and accumulated the pollutants around the embedded MOFs, resulting in relative changes in fluorescence intensity. Therefore, the living MOF-plant nanobiohybrids initiate superior selectivity and sensitivity (0.05-0.5 μM) in water for Ag⁺, Cd²⁺, and aniline with a "turn-up" fluorescence response and for Fe³⁺ and Cu²⁺ with "turn-down" fluorescence response in the linear range of 0.05-10 μM with excellent precision and accuracy of 5 and 10%, respectively. With the easy-to-read visual signals under ultraviolet light, the app translates plant luminescent signals into digital information on a smartphone for on-site monitoring of environmental pollutants with high sensitivity and specificity. These results suggest that interfacing synthetic and living materials may contribute to the development of smart sensors for on-site environmental pollutant sensing with high accuracy.

Automation and low-cost proteomics for characterization of the protein corona: experimental methods for big data

Nanoparticles used in biological settings are exposed to proteins that adsorb on the surface forming a protein corona. These adsorbed proteins dictate the subsequent cellular response. A major challenge has been predicting what proteins will adsorb on a given nanoparticle surface. Instead, each new nanoparticle and nanoparticle modification must be tested experimentally to determine what proteins adsorb on the surface. We propose that any future predictive ability will depend on large datasets of protein-nanoparticle interactions. As a first step towards this goal, we have developed an automated workflow using a liquid handling robot to form and isolate protein coronas. As this workflow depends on magnetic separation steps, we test the ability to embed magnetic nanoparticles within a protein nanoparticle. These experiments demonstrate that magnetic separation could be used for any type of nanoparticle in which a magnetic core can be embedded. Higher-throughput corona characterization will also require lower-cost approaches to proteomics. We report a comparison of fast, low-cost, and standard, slower, higher-cost liquid chromatography coupled with mass spectrometry to identify the protein corona. These methods will provide a step forward in the acquisition of the large datasets necessary to predict nanoparticle-protein interactions.

Guiding the design space for nanotechnology to advance sustainable crop production

The globally recognized need to advance more sustainable agriculture and food systems has motivated the emergence of transdisciplinary solutions, which include methodologies that utilize the properties of materials at the nanoscale to address extensive and inefficient resource use. Despite the promising prospects of these nanoscale materials, the potential for large-scale applications directly to the environment and to crops necessitates precautionary measures to avoid unintended consequences. Further, the effects of using engineered nanomaterials (ENMs) in agricultural practices cascade throughout their life cycle and include effects from upstream-embodied resources and emissions from ENM production as well as their potential downstream environmental implications. Building on decades-long research in ENM synthesis, biological and environmental interactions, fate, transport and transformation, there is the opportunity to inform the sustainable design of nano-enabled agrochemicals. Here we perform a screening-level analysis that considers the system-wide benefits and costs for opportunities in which ENMs can advance the sustainability of crop-based agriculture. These include their on-farm use as (1) soil amendments to offset nitrogen fertilizer inputs, (2) seed coatings to increase germination rates and (3) foliar sprays to enhance yields. In each analysis, the nano-enabled alternatives are compared against the current practice on the basis of performance and embodied energy. In addition to identifying the ENM compositions and application approaches with the greatest potential to sustainably advance crop production, we present a holistic, prospective, systems-based approach that promotes emerging alternatives that have net performance and environmental benefits.

Decoding Plant-Environment Interactions That Influence Crop Agronomic Traits

To ensure food security in the face of increasing global demand due to population growth and progressive urbanization, it will be crucial to integrate emerging technologies in multiple disciplines to accelerate overall throughput of gene discovery and crop breeding. Plant agronomic traits often appear during the plants' later growth stages due to the cumulative effects of their lifetime interactions with the environment. Therefore, decoding plant-environment interactions by elucidating plants' temporal physiological responses to environmental changes throughout their lifespans will facilitate the identification of genetic and environmental factors, timing and pathways that influence complex end-point agronomic traits, such as yield. Here, we discuss the expected role of the life-course approach to monitoring plant and crop health status in improving crop productivity by enhancing the understanding of plant-environment interactions. We review recent advances in analytical technologies for monitoring health status in plants based on multi-omics analyses and strategies for integrating heterogeneous datasets from multiple omics areas to identify informative factors associated with traits of interest. In addition, we showcase emerging phenomics techniques that enable the noninvasive and continuous monitoring of plant growth by various means, including three-dimensional phenotyping, plant root phenotyping, implantable/injectable sensors and affordable phenotyping devices. Finally, we present an integrated review of analytical technologies and applications for monitoring plant growth, developed across disciplines, such as plant science, data science and sensors and Internet-of-things technologies, to improve plant productivity.

Effect of Cationic Brush-Type Copolymers on the Colloidal Stability of GdPO4 Particles with Different Morphologies in Biological Aqueous Media

In this study, we present the synthesis of cationic brush-type polyelectrolytes and their use in the stabilization of GdPO4 particles in aqueous media. Polymers of various compositions were synthesized via the RAFT polymerization route. SEC equipped with triple detection (RI, DP, RALS, and LALS) was used to determine the molecular parameters (Mn, Mw, Mw/Mn). The exact composition of synthesized polymers was determined using NMR spectroscopy. Cationic brush-type polymers were used to improve the stability of aqueous GdPO4 particle dispersions. First, the IEPs of GdPO4 particles with different morphologies (nanorods, hexagonal nanoprisms, and submicrospheres) were determined by measuring the zeta potential of bare particle dispersions at various pH values. Afterward, cationic brush-type polyelectrolytes with different compositions were used for the surface modification of GdPO4 particles (negatively charged in alkaline media under a pH value of ∼10.6). The concentration and composition effects of used polymers on the change in particle surface potential and stability (DLS measurements) in dispersions were investigated and presented in this work. The most remarkable result of this study is redispersible GdPO4 nanoparticle colloids with increased biocompatibility and stability as well as new insights into possible cationic brush-type polyelectrolyte applicability in both scientific and commercial fields.

Aptamer-Based Biosensors for Environmental Monitoring

Due to their relative synthetic and chemical simplicity compared to antibodies, aptamers afford enhanced stability and functionality for the detection of environmental contaminants and for use in environmental monitoring. Furthermore, nucleic acid aptamers can be selected for toxic targets which may prove difficult for antibody development. Of particular relevance, aptamers have been selected and used to develop biosensors for environmental contaminants such as heavy metals, small-molecule agricultural toxins, and water-borne bacterial pathogens. This review will focus on recent aptamer-based developments for the detection of diverse environmental contaminants. Within this domain, aptamers have been combined with other technologies to develop biosensors with various signal outputs. The goal of much of this work is to develop cost-effective, user-friendly detection methods that can complement or replace traditional environmental monitoring strategies. This review will highlight recent examples in this area. Additionally, with innovative developments such as wearable devices, sentinel materials, and lab-on-a-chip designs, there exists significant potential for the development of multifunctional aptamer-based biosensors for environmental monitoring. Examples of these technologies will also be highlighted. Finally, a critical perspective on the field, and thoughts on future research directions will be offered.

Nanomaterial Transformation in the Soil-Plant System: Implications for Food Safety and Application in Agriculture

Engineered nanomaterials (ENMs) have huge potential for improving use efficiency of agrochemicals, crop production, and soil health; however, the behavior and fate of ENMs and the potential for negative long-term impacts to agroecosystems remain largely unknown. In particular, there is a lack of clear understanding of the transformation of ENMs in both soil and plant compartments. The transformation can be physical, chemical, and/or biological, and may occur in soil, at the plant interface, and/or inside the plant. Due to these highly dynamic processes, ENMs may acquire new properties distinct from their original profile; as such, the behavior, fate, and biological effects may also differ significantly. Several essential questions in terms of ENMs transformation are discussed, including the drivers and locations of ENM transformation in the soil-plant system and the effects of ENM transformation on analyte uptake, translocation, and toxicity. The main knowledge gaps in this area are highlighted and future research needs are outlined so as to ensure sustainable nanoenabled agricultural applications.

Metal-Organic Framework Nanoparticles Induce Pyroptosis in Cells Controlled by the Extracellular pH

Ion homeostasis is essential for cellular survival, and elevated concentrations of specific ions are used to start distinct forms of programmed cell death. However, investigating the influence of certain ions on cells in a controlled way has been hampered due to the tight regulation of ion import by cells. Here, it is shown that lipid-coated iron-based metal-organic framework nanoparticles are able to deliver and release high amounts of iron ions into cells. While high concentrations of iron often trigger ferroptosis, here, the released iron induces pyroptosis, a form of cell death involving the immune system. The iron release occurs only in slightly acidic extracellular environments restricting cell death to cells in acidic microenvironments and allowing for external control. The release mechanism is based on endocytosis facilitated by the lipid-coating followed by degradation of the nanoparticle in the lysosome via cysteine-mediated reduction, which is enhanced in slightly acidic extracellular environment. Thus, a new functionality of hybrid nanoparticles is demonstrated, which uses their nanoarchitecture to facilitate controlled ion delivery into cells. Based on the selectivity for acidic microenvironments, the described nanoparticles may also be used for immunotherapy: the nanoparticles may directly affect the primary tumor and the induced pyroptosis activates the immune system.

Design of Active Interfaces Using Responsive Molecular Components

Responsive interfaces are interfaces that show a defined and reversible change in physical properties in response to external stimuli. Typically, responsive interfaces result from the immobilization of responsive molecular components at the interface that translate a nanoscale signal into a macroscopic effect. Responsive interfaces can also be obtained if the topology of the interface can be reversibly changed using an external stimulus. As the surface of any material is its connection to the environment, responsive interfaces provide opportunities for interactive materials which are not only able to change properties upon demand, but also sense their environment and act autonomously. The application of responsive molecular components at interfaces, however, requires chemical and physical compatibility with the material surface of interest, posing a challenge not least in the retention of the responsive functionality. The state of the art in "active" interfaces which display responsive wettability, permeability, or adhesion is discussed, with a particular emphasis on microscale and nanoscale patterning since patterned interfaces can give rise to unique material properties. Finally, perspectives in the development of responsive interfaces, as well as promising approaches for bypassing the most prominent challenges are discussed.

Transport and programmed release of nanoscale cargo from cells by using NETosis

Cells can take up nanoscale materials, which has important implications for understanding cellular functions, biocompatibility as well as biomedical applications. Controlled uptake, transport and triggered release of nanoscale cargo is one of the great challenges in biomedical applications of nanomaterials. Here, we study how human immune cells (neutrophilic granulocytes, neutrophils) take up nanomaterials and program them to release this cargo after a certain time period. For this purpose, we let neutrophils phagocytose DNA-functionalized single-walled carbon nanotubes (SWCNTs) in vitro that fluoresce in the near infrared (980 nm) and serve as sensors for small molecules. Cells still migrate, follow chemical gradients and respond to inflammatory signals after uptake of the cargo. To program release, we make use of neutrophil extracellular trap formation (NETosis), a novel cell death mechanism that leads to chromatin swelling, subsequent rupture of the cellular membrane and release of the cell's whole content. By using the process of NETosis, we can program the time point of cargo release via the initial concentration of stimuli such as phorbol 12-myristate-13-acetate (PMA) or lipopolysaccharide (LPS). At intermediate stimulation, cells continue to migrate, follow gradients and surface cues for around 30 minutes and up to several hundred micrometers until they stop and release the SWCNTs. The transported and released SWCNT sensors are still functional as shown by subsequent detection of the neurotransmitter dopamine and reactive oxygen species (H2O2). In summary, we hijack a biological process (NETosis) and demonstrate how neutrophils transport and release functional nanomaterials.

Targeted delivery of nanomaterials with chemical cargoes in plants enabled by a biorecognition motif

Current approaches for nanomaterial delivery in plants are unable to target specific subcellular compartments with high precision, limiting our ability to engineer plant function. We demonstrate a nanoscale platform that targets and delivers nanomaterials with biochemicals to plant photosynthetic organelles (chloroplasts) using a guiding peptide recognition motif. Quantum dot (QD) fluorescence emission in a low background window allows confocal microscopy imaging and quantitative detection by elemental analysis in plant cells and organelles. QD functionalization with β-cyclodextrin molecular baskets enables loading and delivery of diverse chemicals, and nanoparticle coating with a rationally designed and conserved guiding peptide targets their delivery to chloroplasts. Peptide biorecognition provides high delivery efficiency and specificity of QD with chemical cargoes to chloroplasts in plant cells in vivo (74.6 ± 10.8%) and more specific tunable changes of chloroplast redox function than chemicals alone. Targeted delivery of nanomaterials with chemical cargoes guided by biorecognition motifs has a broad range of nanotechnology applications in plant biology and bioengineering, nanoparticle-plant interactions, and nano-enabled agriculture.

Monitoring Plant Health with Near-Infrared Fluorescent H2O2 Nanosensors

Near-infrared (nIR) fluorescent single-walled carbon nanotubes (SWCNTs) were designed and interfaced with leaves of Arabidopsis thaliana plants to report hydrogen peroxide (H₂O₂), a key signaling molecule associated with the onset of plant stress. The sensor nIR fluorescence response (>900 nm) is quenched by H₂O₂ with selectivity against other stress-associated signaling molecules and within the plant physiological range (10-100 H₂O₂ μM). In vivo remote nIR imaging of H₂O₂ sensors enabled optical monitoring of plant health in response to stresses including UV-B light (-11%), high light (-6%), and a pathogen-related peptide (flg22) (-10%), but not mechanical leaf wounding (<3%). The sensor's high biocompatibility was reflected on similar leaf cell death (<5%) and photosynthetic rates to controls without SWCNT. These optical nanosensors report early signs of stress and will improve our understanding of plant stress communication, provide novel tools for precision agriculture, and optimize the use of agrochemicals in the environment.

Real-time detection of wound-induced H2O2 signalling waves in plants with optical nanosensors

Decoding wound signalling in plants is critical for understanding various aspects of plant sciences, from pest resistance to secondary metabolite and phytohormone biosynthesis. The plant defence responses are known to primarily involve NADPH-oxidase-mediated H₂O₂ and Ca²⁺ signalling pathways, which propagate across long distances through the plant vasculature and tissues. Using non-destructive optical nanosensors, we find that the H₂O₂ concentration profile post-wounding follows a logistic waveform for six plant species: lettuce (Lactuca sativa), arugula (Eruca sativa), spinach (Spinacia oleracea), strawberry blite (Blitum capitatum), sorrel (Rumex acetosa) and Arabidopsis thaliana, ranked in order of wave speed from 0.44 to 3.10 cm min^-1. The H₂O₂ wave tracks the concomitant surface potential wave measured electrochemically. We show that the plant RbohD glutamate-receptor-like channels (GLR3.3 and GLR3.6) are all critical to the propagation of the wound-induced H₂O₂ wave. Our findings highlight the utility of a new type of nanosensor probe that is species-independent and capable of real-time, spatial and temporal biochemical measurements in plants.

Silver Nanoparticles as Colorimetric Sensors for Water Pollutants

This review provides an up-to-date overview on silver nanoparticles-based materials suitable as optical sensors for water pollutants. The topic is really hot considering the implications for human health and environment due to water pollutants. In fact, the pollutants present in the water disturb the spontaneity of life-related mechanisms, such as the synthesis of cellular constituents and the transport of nutrients into cells, and this causes long / short-term diseases. For this reason, research continuously tends to develop always innovative, selective and efficient processes / technologies to remove pollutants from water. In this paper we will report on the silver nanoparticles synthesis, paying attention to the stabilizers and mostly used ligands, to the characterizations, to the properties and applications as colorimetric sensors for water pollutants. As water pollutants our attention will be focused on several heavy metals ions, such as Hg(II), Ni(II),Cu(II), Fe(III), Mn(II), Cr(III/V) Co(II) Cd(II), Pb(II), due to their dangerous effects on human health. In addition, several systems based on silver nanoparticles employed as pesticides colorimetric sensors in water will be also discussed. All of this with the aim to provide to readers a guide about recent advanced silver nanomaterials, used as colorimetric sensors in water.

Exfoliated near infrared fluorescent silicate nanosheets for (bio)photonics

Imaging of complex (biological) samples in the near-infrared (NIR) is beneficial due to reduced light scattering, absorption, phototoxicity, and autofluorescence. However, there are few NIR fluorescent materials known and suitable for biomedical applications. Here we exfoliate the layered pigment CaCuSi4O10 (Egyptian Blue, EB) via ball milling and facile tip sonication into NIR fluorescent nanosheets (EB-NS). The size of EB-NS can be tailored to diameters <20 nm and heights down to 1 nm. EB-NS fluoresce at 910 nm and the fluorescence intensity correlates with the number of Cu2+ ions. Furthermore, EB-NS display no bleaching and high brightness compared with other NIR fluorophores. The versatility of EB-NS is demonstrated by in-vivo single-particle tracking and microrheology measurements in Drosophila melanogaster embryos. EB-NS can be uptaken by plants and remotely detected in a low-cost stand-off detection setup. In summary, EB-NS have the potential for a wide range of bioimaging applications.

Variable-Temperature Electron Transport and Dipole Polarization Turning Flexible Multifunctional Microsensor beyond Electrical and Optical Energy

Humans are undergoing a fateful transformation focusing on artificial intelligence, quantum information technology, virtual reality, etc., which is inseparable from intelligent nano-micro devices. However, the booming of "Big Data" brings about an even greater challenge by growing electromagnetic radiation. Herein, an innovative flexible multifunctional microsensor is proposed, opening up a new horizon for intelligent devices. It integrates "non-crosstalk" multiple perception and green electromagnetic interference shielding only in one pixel, with satisfactory sensitivity and fast information feedback. Importantly, beneficial by deep insight into the variable-temperature electromagnetic response, the microsensor tactfully transforms the urgent threat of electromagnetic radiation into "wealth," further integrating self-power. This result will refresh researchers' realization of next-generation devices, ushering in a new direction for aerospace engineering, remote sensing, communications, medical treatment, biomimetic robot, prosthetics, etc.

UV Lithography-Assisted Fabrication of Low-Cost Copper Electrodes Modified with Gold Nanostructures for Improved Analyte Detection

An in-house UV lithography setup has been optimized to fabricate low-cost disposable electrochemical sensing Cu electrodes using a copper clad board. In view of the high oxidation probability of copper, the low-cost electrodes were modified using different gold nanostructures and a conducing polymer PEDOT:PSS to attain maximal signal output and improved shelf-life. Zero-dimensional (0D) gold nanoparticles (∼40 nm) and three-dimensional (3D) gold nanoflowers (∼38 nm) mixed with PEDOT:PSS were used as signal-enhancing conductors for the ultrasensitive detection of our model contaminant, methylene blue dye (MB). The bare copper electrode was sensitive to MB, linearly within the range of 4-100 μM, with a limit of detection of 3.49 μM. While for gold nanoparticle-PEDOT:PSS-modified electrode, the sensitivity of the electrode was found to increase linearly in the range of 0.01-0.1 μM, and for gold nanoflowers-PEDOT:PSS, the sensitivity achieved was 0.01-0.1 μM with the LOD as 0.0022 μM. For a PEDOT:PSS-modified Cu electrode, used as a comparative to study the contributing role of gold nanostructures towards improved sensitivity, the linearity was found to be in the range of 0.1-1.9 μM with the LOD as 0.0228 μM. A 6 times improvement in signal sensitivity for the nanoflower-PEDOT:PSS electrode compared to the nanoparticle-PEDOT:PSS-modified electrode indicates the influence of nanoparticle shape on the electrode efficiency. 3D gold nanoflowers with a large surface area-to-volume ratio and a high catalytic activity prove to be a superior choice for electrode modification.