Gold Nanoparticles and Plant Pathogens: An Overview and Prospective for Biosensing in Forestry.

Plant diseases and their diagnoses are currently one of the global challenges and causes significant impact to the economy of farmers and industries depending on plant-based products. Plant pathogens such as viruses, bacteria, fungi, and pollution caused by the nanomaterial, as well other important elements of pollution, are the main reason for the loss of plants in agriculture and in forest ecosystems. Presently, various techniques are used to detect pathogens in trees, which includes DNA-based techniques, as well as other microscopy based identification and detection. However, these methodologies require complex instruments and time. Lately, nanomaterial-based new biosensing systems for early detection of diseases, with specificity and sensitivity, are developed and applied. This review highlights the nanomaterial-based biosensing methods of disease detection. Precise and time effective identification of plant pathogens will help to reduce losses in agriculture and forestry. This review focuses on various plant diseases and the requirements for a reliable, fast, and cost-effective testing method, as well as new biosensing technologies for the detection of diseases of field plants in forests at early stages of their growth.

MicroRNA amplification and detection technologies: opportunities and challenges for point of care diagnostics.

The volume of point of care (POC) testing continues to grow steadily due to the increased availability of easy-to-use devices, thus making it possible to deliver less costly care closer to the patient site in a shorter time relative to the central laboratory services. A novel class of molecules called microRNAs have recently gained attention in healthcare management for their potential as biomarkers for human diseases. The increasing interest of miRNAs in clinical practice has led to an unmet need for assays that can rapidly and accurately measure miRNAs at the POC. However, the most widely used methods for analyzing miRNAs, including Northern blot-based platforms, in situ hybridization, reverse transcription qPCR, microarray, and next-generation sequencing, are still far from being used as ideal POC diagnostic tools, due to considerable time, expertize required for sample preparation, and in terms of miniaturizations making them suitable platforms for centralized labs. In this review, we highlight various existing and upcoming technologies for miRNA amplification and detection with a particular emphasis on the POC testing industries. The review summarizes different miRNA targets and signals amplification-based assays, from conventional methods to alternative technologies, such as isothermal amplification, paper-based, oligonucleotide-templated reaction, nanobead-based, electrochemical signaling- based, and microfluidic chip-based strategies. Based on critical analysis of these technologies, the possibilities and feasibilities for further development of POC testing for miRNA diagnostics are addressed and discussed.

Impedance nanopore biosensor: influence of pore dimensions on biosensing performance.

Knowledge about electrochemical and electrical properties of nanopore structures and the influence of pore dimensions on these properties is important for the development of nanopore biosensing devices. The aim of this study was to explore the influence of nanopore dimensions (diameter and length) on biosensing performance using non-faradic electrochemical impedance spectroscopy (EIS). Nanoporous alumina membranes (NPAMs) prepared by self-ordered electrochemical anodization of aluminium were used as model nanopore sensing platforms. NPAMs with different pore diameters (25-65 nm) and lengths (4-18 µm) were prepared and the internal pore surface chemistry was modified by covalently attaching streptavidin and biotin. The performance of this antibody nanopore biosensing platform was evaluated using various concentrations of biotin as a model analyte. EIS measurements of pore resistivity and conductivity were carried out for pores with different diameters and lengths. The results showed that smaller pore dimensions of 25 nm and pore lengths up to 10 µm provide better biosensing performance.

The influence of nanopore dimensions on the electrochemical properties of nanopore arrays studied by impedance spectroscopy.

The understanding of the electrochemical properties of nanopores is the key factor for better understanding their performance and applications for nanopore-based sensing devices. In this study, the influence of pore dimensions of nanoporous alumina (NPA) membranes prepared by an anodization process and their electrochemical properties as a sensing platform using impedance spectroscopy was explored. NPA with four different pore diameters (25 nm, 45 nm and 65 nm) and lengths (5 µm to 20 µm) was used and their electrochemical properties were explored using different concentration of electrolyte solution (NaCl) ranging from 1 to 100 µM. Our results show that the impedance and resistance of nanopores are influenced by the concentration and ion species of electrolytes, while the capacitance is independent of them. It was found that nanopore diameters also have a significant influence on impedance due to changes in the thickness of the double layer inside the pores.

Lateral flow assays: Progress and evolution of recent trends in point-of-care applications.

Paper based point-of-care (PoC) detection platforms applying lateral flow assays (LFAs) have gained paramount approval in the diagnostic domain as well as in environmental applications owing to their ease of utility, low cost, and rapid signal readout. It has centralized the aspect of self-evaluation exhibiting promising potential in the last global pandemic era of Covid-19 implementing rapid management of public health in remote areas. In this perspective, the present review is focused towards landscaping the current framework of LFAs along with integration of components and characteristics for improving the assay by pushing the detection limits. The review highlights the synergistic aspects of assay designing, sample enrichment strategies, novel nanomaterials-based signal transducers, and high-end analytical techniques that contribute significantly towards sensitivity and specificity enhancement. Various recent studies are discussed supporting the innovations in LFA systems that focus upon the accuracy and reliability of rapid PoC testing. The review also provides a comprehensive overview of all the possible difficulties in commercialization of LFAs subjecting its applicability to pathogen surveillance, water and food testing, disease diagnostics, as well as to agriculture and environmental issues.

SERS sensing for cancer biomarker: Approaches and directions.

These days, cancer is thought to be more than just one illness, with several complex subtypes that require different screening approaches. These subtypes can be distinguished by the distinct markings left by metabolites, proteins, miRNA, and DNA. Personalized illness management may be possible if cancer is categorized according to its biomarkers. In order to stop cancer from spreading and posing a significant risk to patient survival, early detection and prompt treatment are essential. Traditional cancer screening techniques are tedious, time-consuming, and require expert personnel for analysis. This has led scientists to reevaluate screening methodologies and make use of emerging technologies to achieve better results. Using time and money saving techniques, these methodologies integrate the procedures from sample preparation to detection in small devices with high accuracy and sensitivity. With its proven potential for biomedical use, surface-enhanced Raman scattering (SERS) has been widely used in biosensing applications, particularly in biomarker identification. Consideration was given especially to the potential of SERS as a portable clinical diagnostic tool. The approaches to SERS-based sensing technologies for both invasive and non-invasive samples are reviewed in this article, along with sample preparation techniques and obstacles. Aside from these significant constraints in the detection approach and techniques, the review also takes into account the complexity of biological fluids, the availability of biomarkers, and their sensitivity and selectivity, which are generally lowered. Massive ways to maintain sensing capabilities in clinical samples are being developed recently to get over this restriction. SERS is known to be a reliable diagnostic method for treatment judgments. Nonetheless, there is still room for advancement in terms of portability, creation of diagnostic apps, and interdisciplinary AI-based applications. Therefore, we will outline the current state of technological maturity for SERS-based cancer biomarker detection in this article. The review will meet the demand for reviewing various sample types (invasive and non-invasive) of cancer biomarkers and their detection using SERS. It will also shed light on the growing body of research on portable methods for clinical application and quick cancer detection.

Plasmonic nanoparticle sensors: current progress, challenges, and future prospects.

Plasmonic nanoparticles (NPs) have played a significant role in the evolution of modern nanoscience and nanotechnology in terms of colloidal synthesis, general understanding of nanocrystal growth mechanisms, and their impact in a wide range of applications. They exhibit strong visible colors due to localized surface plasmon resonance (LSPR) that depends on their size, shape, composition, and the surrounding dielectric environment. Under resonant excitation, the LSPR of plasmonic NPs leads to a strong field enhancement near their surfaces and thus enhances various light-matter interactions. These unique optical properties of plasmonic NPs have been used to design chemical and biological sensors. Over the last few decades, colloidal plasmonic NPs have been greatly exploited in sensing applications through LSPR shifts (colorimetry), surface-enhanced Raman scattering, surface-enhanced fluorescence, and chiroptical activity. Although colloidal plasmonic NPs have emerged at the forefront of nanobiosensors, there are still several important challenges to be addressed for the realization of plasmonic NP-based sensor kits for routine use in daily life. In this comprehensive review, researchers of different disciplines (colloidal and analytical chemistry, biology, physics, and medicine) have joined together to summarize the past, present, and future of plasmonic NP-based sensors in terms of different sensing platforms, understanding of the sensing mechanisms, different chemical and biological analytes, and the expected future technologies. This review is expected to guide the researchers currently working in this field and inspire future generations of scientists to join this compelling research field and its branches.

Microfluidic Bio-Sensors and Their Applications.

Biosensors are a promising tool for a wide variety of target analyte detection and enable point-of-care diagnostics with reduced volume and space [...].

Nano-Biosensors for Detection and Monitoring (Volume 1).

Nano-biosensing technology is a continuously evolving and expanding field with applications concerning biological substances and sensing platforms, which include the detection of chemical, biological, and environmental elements and welfare [...].

Progress in Fluorescence Biosensing and Food Safety towards Point-of-Detection (PoD) System.

The detection of pathogens in food substances is of crucial concern for public health and for the safety of the natural environment. Nanomaterials, with their high sensitivity and selectivity have an edge over conventional organic dyes in fluorescent-based detection methods. Advances in microfluidic technology in biosensors have taken place to meet the user criteria of sensitive, inexpensive, user-friendly, and quick detection. In this review, we have summarized the use of fluorescence-based nanomaterials and the latest research approaches towards integrated biosensors, including microsystems containing fluorescence-based detection, various model systems with nano materials, DNA probes, and antibodies. Paper-based lateral-flow test strips and microchips as well as the most-used trapping components are also reviewed, and the possibility of their performance in portable devices evaluated. We also present a current market-available portable system which was developed for food screening and highlight the future direction for the development of fluorescence-based systems for on-site detection and stratification of common foodborne pathogens.

Collaborative Machine Learning: Schemes, Robustness, and Privacy.

Distributed machine learning (ML) was originally introduced to solve a complex ML problem in a parallel way for more efficient usage of computation resources. In recent years, such learning has been extended to satisfy other objectives, namely, performing learning in situ on the training data at multiple locations and keeping the training datasets private while still allowing sharing of the model. However, these objectives have led to considerable research on the vulnerabilities of distributed learning both in terms of privacy concerns of the training data and the robustness of the learned overall model due to bad or maliciously crafted training data. This article provides a comprehensive survey of various privacy, security, and robustness issues in distributed ML.

Microfluidic-Assisted Synthesis of Metal-Organic Framework -Alginate Micro-Particles for Sustained Drug Delivery.

Drug delivery systems (DDS) are continuously being explored since humans are facing more numerous complicated diseases than ever before. These systems can preserve the drug's functionality and improve its efficacy until the drug is delivered to a specific site within the body. One of the least used materials for this purpose are metal-organic frameworks (MOFs). MOFs possess many properties, including their high surface area and the possibility for the addition of functional surface moieties, that make them ideal drug delivery vehicles. Such properties can be further improved by combining different materials (such as metals or ligands) and utilizing various synthesis techniques. In this work, the microfluidic technique is used to synthesize Zeolitic Imidazole Framework-67 (ZIF-67) containing cobalt ions as well as its bimetallic variant with cobalt and zinc as ZnZIF-67 to be subsequently loaded with diclofenac sodium and incorporated into sodium alginate beads for sustained drug delivery. This study shows the utilization of a microfluidic approach to synthesize MOF variants. Furthermore, these MOFs were incorporated into a biopolymer (sodium alginate) to produce a reliable DDS which can perform sustained drug releases for up to 6 days (for 90% of the full amount released), whereas MOFs without the biopolymer showed sudden release within the first day.

Performance Evaluation of Magnetic Resonance Coupling Method for Intra-Body Network (IBNet).

Effective management of emerging medical devices can lead to new insights in healthcare. Thus, human body communication (HBC) is becoming increasingly important. In this paper, we present magnetic resonance (MR) coupling as a promising method for the intra-body network (IBNet). The study reveals that MR coupling can effectively send or receive signals in biological tissue, with a maximum path loss of PL ≤ 33 dB (i.e. at 13.56 MHz), which is lower than other methods (e.g., galvanic, capacitive, or RF) for the same distance (d = 100 cm). The angular orientation of the transmitter and receiver coils at short and long distances also show a minor variation of the path loss (0.19 ≤ ∆PL ≤ 0.62 dB), but more dependency on the distance (0.0547 dB/cm). Additionally, different postures during the MR coupling essentially does not affect path loss ( ∆PL ≤ ± 0.21 dB). In the multi-nodal transmission scenario, the MR coupling demonstrates that two nodes can simultaneously receive signals with -16.77 dBm loss at 60 cm and 100 cm distances, respectively. Such multi-node MR transmission can be utilized for communication, sensing, and powering wearable and implantable devices.

Recent Advances in Microfluidic Platform for Physical and Immunological Detection and Capture of Circulating Tumor Cells.

CTCs (circulating tumor cells) are well-known for their use in clinical trials for tumor diagnosis. Capturing and isolating these CTCs from whole blood samples has enormous benefits in cancer diagnosis and treatment. In general, various approaches are being used to separate malignant cells, including immunomagnets, macroscale filters, centrifuges, dielectrophoresis, and immunological approaches. These procedures, on the other hand, are time-consuming and necessitate multiple high-level operational protocols. In addition, considering their low efficiency and throughput, the processes of capturing and isolating CTCs face tremendous challenges. Meanwhile, recent advances in microfluidic devices promise unprecedented advantages for capturing and isolating CTCs with greater efficiency, sensitivity, selectivity and accuracy. In this regard, this review article focuses primarily on the various fabrication methodologies involved in microfluidic devices and techniques specifically used to capture and isolate CTCs using various physical and biological methods as well as their conceptual ideas, advantages and disadvantages.

Analogous foliar uptake and leaf-to-root translocation of micelle nanoparticles in two dicot plants of diverse families.

Bio-inspired nanoparticles, including metallic, micelles, and polymeric, have been explored as a novel tool in the quest for effective and safe agrochemicals. Although nanoparticles (NPs) are being rapidly investigated for their usefulness in agricultural production and protection, little is known about the behaviour and interaction of oil-in-water micelle nanoparticles or nano-micelles (NM) with plants. We loaded a bio-based resin inherent of tree from the Pinaceae family as active material and produced stable nano-micelles using a natural emulsifier system. Here, we show that foliar-applied nano-micelle can translocate in two dicot plants belonging to diverse families (Coriandrum sativum -Apiaceae and Trigonella foenumgraecum -Fabaceae) via similar mode. Fluorescent-tagged NM (average diameter 11.20nm) showed strong signals and higher intensities as revealed by confocal imaging and exhibited significant adhesion in leaf compared to control. The NM subsequently translocates to other parts of the plants. As observed by SEM, the leaf surface anatomies revealed higher stomata densities and uptake of NM by guard cells; furthermore, larger extracellular spaces in mesophyll cells indicate a possible route of NM translocation. In addition, NM demonstrated improved wetting-spreading as illustrated by contact angle measurement. In a field bioassay, a single spray application of NM offered protection from aphid infestation for at least 9 days. There were no signs of phytotoxicity in plants post-application of NM. We conclude that pine resin-based nano-micelle provides an efficient, safe, and sustainable alternative for agricultural applications.

Electrochemical Sensing in 3D Cell Culture Models: New Tools for Developing Better Cancer Diagnostics and Treatments.

Currently, conventional pre-clinical in vitro studies are primarily based on two-dimensional (2D) cell culture models, which are usually limited in mimicking the real three-dimensional (3D) physiological conditions, cell heterogeneity, cell to cell interaction, and extracellular matrix (ECM) present in living tissues. Traditionally, animal models are used to mimic the 3D environment of tissues and organs, but they suffer from high costs, are time consuming, bring up ethical concerns, and still present many differences when compared to the human body. The applications of microfluidic-based 3D cell culture models are advantageous and useful as they include 3D multicellular model systems (MCMS). These models have demonstrated potential to simulate the in vivo 3D microenvironment with relatively low cost and high throughput. The incorporation of monitoring capabilities in the MCMS has also been explored to evaluate in real time biophysical and chemical parameters of the system, for example temperature, oxygen, pH, and metabolites. Electrochemical sensing is considered as one of the most sensitive and commercially adapted technologies for bio-sensing applications. Amalgamation of electrochemical biosensing with cell culture in microfluidic devices with improved sensitivity and performance are the future of 3D systems. Particularly in cancer, such models with integrated sensing capabilities can be crucial to assess the multiple parameters involved in tumour formation, proliferation, and invasion. In this review, we are focusing on existing 3D cell culture systems with integrated electrochemical sensing for potential applications in cancer models to advance diagnosis and treatment. We discuss their design, sensing principle, and application in the biomedical area to understand the potential relevance of miniaturized electrochemical hybrid systems for the next generation of diagnostic platforms for precision medicine.

Solid Phase PCR on 3D Microstructure ArrayChip for Pathogen Detection Application.

Advanced free angle photolithography (FAPL) is presented for making 3D supercritical angle fluorescence (SAF) microstructures and transfer them on to polymeric chips using injection molding technique for low-cost microfluidic devices embedded with optical sensing structures. A solid phase polymerase chain reaction (SP-PCR) is used as model technique, which allows rapid and sensitive detection of pathogen DNA on-chip. This article presents the detailed fabrication of SAF structure and SP-PCR application on SAF structure for pathogen detection. This protocol of developing SAF structures using the FAPL process, increases the number of SAF per mm2. FAPL was performed via a motorized stage to control the angle of incidence and to achieve the desired bucket-shapes (dimensions of 50 µm to 150 µm with a slope) required for the 3D optical sensing. Due to the unique properties of SAF structures, it enhances the fluorescent signal by 46 times. Increasing the number of SAF structures and reducing the size resulted in reduction of sample volume required per test along with improvement in the limit of detection (LOD) due to a smaller size. This article also presents the experimental details of SP-PCR using DNA oligos bound to the SAF structures for on-chip pathogen detection and a comparison between different sizes of SAF structures. The direct on-chip SP-PCR paves the path for the application of this technique in point-of-care devices.

Human Epididymis Protein 4 Quantification and Interaction Network Analysis in Seminal Plasma.

BACKGROUND: A well-known tissue marker of ovarian cancer, Human Epididymis protein 4 (HE4) is the member of whey acidic four-disulfide core proteins family. Purified from human seminal plasma and characterized as a cross-class protease inhibitor, HE4 was proposed to shield spermatozoa against proteolytic factors. However, its exact biological function is unknown. Proteins usually function in conjunction with other proteins in the system and thus, identification and analysis of protein networks become essential to decode protein functions. OBJECTIVE: This study was performed to explore possible role(s) of HE4 in reproductive physiology via identification of its interactome in human seminal plasma. METHODS: HE4 binding proteins were identified through co-immunoprecipitation and MALDITOF/ MS analysis. Also, HE4 was quantified by ELISA in fertile and infertile human seminal plasma samples. RESULTS: Ten HE4 binding proteins were identified, viz. protein phosphatase 1 regulatory subunit 21, protein kinase CLK3, Ankyrin repeat domain-containing protein36A, prostatic acid phosphatase, KIF5C, Spectrin repeat containing, nuclear envelope 1, isoform CRAf, tropomyosin 4, vezatin, utrophin and fibronectin1. This interaction network suggests that HE4 plays multiple roles, specifically in capacitation, sperm motility and maturation. Further, HE4 concentration in human seminal plasma samples was determined by Elisa. Higher HE4 expression in normozoospermia compared to azoospermia and asthenozoospermia affirms its importance in fertilization. CONCLUSION: Based on identified interactome, it is plausible that HE4 plays a crucial role in fertilization, specifically in sperm maturation, motility and capacitation.

Correction to "Targeted Reinforcement of Macrophage Reprogramming Toward M2 Polarization by IL-4-Loaded Hyaluronic Acid Particles".

[This corrects the article DOI: 10.1021/acsomega.8b03182.].

Rapid detection of Salmonella enterica in food samples by a novel approach with combination of sample concentration and direct PCR.

Foodborne salmonellosis remains a major economic burden worldwide and particularly for food industries. The diverse and complexity of food matrices pose great challenges for rapid and ultra-sensitive detection of Salmonella in food samples. In this study, combination of pathogen pre-concentration with rapid molecular identification is presented to overcome these challenges. This combination enabled effective real-time PCR detection of low levels of Salmonella enterica serovar Typhimurium without culture enrichment. Anti-salmonella antibody, immobilized on protein AG-magnetic beads, could efficiently concentrate Salmonella Typhimurium with a capturing efficiency of 95%. In the direct PCR, a strong linear relationship between bacteria concentration and the number of cycles was observed with a relative PCR efficiency of ∼92% resulting in a limit of detection (LoD) of ∼2 CFU/mL. Analysis of spiked food samples that include vegetable salad, egg yolk, egg white, whole egg and minced pork meat has validated the precision of the method. A relative accuracy of 98.3% with a sensitivity of 91.6% and specificity of 100% was achieved in the Salmonella spiked food samples. The use of a Phusion hot start DNA polymerase with a high tolerance to possible PCR inhibitors allowed the integration of direct PCR, and thereby reducing the duration of analysis to less than 3 h. The Cohen's kappa index showed excellent agreement (0.88) signifying the capability of this method to overcome the food matrix effects in rapid and ultra-sensitive detection of Salmonella in food. This approach may lay a future platform for the integration into a Lab-on-a-chip system for online monitoring of foodborne pathogens.