Microfluidic platforms integrated with nano-sensors for point-of-care bioanalysis.

Microfluidic technology provides a portable, cost-effective, and versatile tool for point-of-care (POC) bioanalysis because of its associated advantages such as fast analysis, low volumes of reagent consumption, and high portability. Along with microfluidics, the application of nanomaterials in biosensing has attracted lots of attention due to their unique physical and chemical properties for enhanced signal modulation such as signal amplification and signal transduction for POC bioanalysis. Hence, an enormous number of microfluidic devices integrated with nano-sensors have been developed for POC bioanalysis targeting low-resource settings. Herein, we review recent advances in POC bioanalysis on nano-sensor-based microfluidic platforms. We first briefly summarized the different types of cost-effective microfluidic platforms, followed by a concise introduction to nanomaterial-based biosensors. Then, we highlighted the application of microfluidic platforms integrated with nano-sensors for POC bioanalysis. Finally, we discussed the current limitations and perspective trends of the nano-sensor-based microfluidic platforms for POC bioanalysis.

Securing the Insecure: A First-Line-of-Defense for Body-Centric Nanoscale Communication Systems Operating in THz Band.

This manuscript presents a novel mechanism (at the physical layer) for authentication and transmitter identification in a body-centric nanoscale communication system operating in the terahertz (THz) band. The unique characteristics of the propagation medium in the THz band renders the existing techniques (say for impersonation detection in cellular networks) not applicable. In this work, we considered a body-centric network with multiple on-body nano-senor nodes (of which some nano-sensors have been compromised) who communicate their sensed data to a nearby gateway node. We proposed to protect the transmissions on the link between the legitimate nano-sensor nodes and the gateway by exploiting the path loss of the THz propagation medium as the fingerprint/feature of the sender node to carry out authentication at the gateway. Specifically, we proposed a two-step hypothesis testing mechanism at the gateway to counter the impersonation (false data injection) attacks by malicious nano-sensors. To this end, we computed the path loss of the THz link under consideration using the high-resolution transmission molecular absorption (HITRAN) database. Furthermore, to refine the outcome of the two-step hypothesis testing device, we modeled the impersonation attack detection problem as a hidden Markov model (HMM), which was then solved by the classical Viterbi algorithm. As a bye-product of the authentication problem, we performed transmitter identification (when the two-step hypothesis testing device decides no impersonation) using (i) the maximum likelihood (ML) method and (ii) the Gaussian mixture model (GMM), whose parameters are learned via the expectation-maximization algorithm. Our simulation results showed that the two error probabilities (missed detection and false alarm) were decreasing functions of the signal-to-noise ratio (SNR). Specifically, at an SNR of 10 dB with a pre-specified false alarm rate of 0.2, the probability of correct detection was almost one. We further noticed that the HMM method outperformed the two-step hypothesis testing method at low SNRs (e.g., a 10% increase in accuracy was recorded at SNR = -5 dB), as expected. Finally, it was observed that the GMM method was useful when the ground truths (the true path loss values for all the legitimate THz links) were noisy.

Two Novel BODIPY-Functional Magnetite Fluorescent Nano-Sensors for Detecting of Cr(VI) Ions in Aqueous Solutions.

In this study, we developed two different very sensitive magnetite fluorescent Fe3O4@SiO2-TPED-BODIPY and Fe3O4@SiO2-TMPTA-BODIPY nano-sensors for the selective detection of Cr(VI) ions. The Cr(VI) metal ions sensing is based on the fluorescent quenching of BODIPY functionalized with Fe3O4@SiO2-TPED and Fe3O4@SiO2-TMPTA nanoparticles in the ethanol-water environment. Characterization of the newly synthesized fluorescent BODIPY compound was performed on a 1H and 13C-NMR spectrometer. The morphology, chemical and physical properties of the sensing nano-sensors were studied by transmission thermogravimetric analysis (TGA), X-ray diffraction (XRD), energy dispersive X-ray (EDX), scanning electron microscopy (SEM), FT-IR spectroscopy, and transmission electron microscopy (TEM). UV-visible and fluorescent spectroscopy were used to characterize BODIPY functionalized magnetite fluorescent nano-sensors. Characterization measurements revealed that the mean particle diameter of magnetite fluorescent Fe3O4@SiO2-TPED-BODIPY and Fe3O4@SiO2-TMPTA-BODIPY nano-sensors was 18.5 and 19 nm, respectively. The magnetite fluorescent Fe3O4@SiO2-TPED-BODIPY and Fe3O4@SiO2-TMPTA-BODIPY nano-sensors (0.1 gL-1 in EtOH/H2O, v/v (3/7)) showed fluorescence quenching responses towards Cr(VI) ions in the medium at pH:1. The fluorescence quenches of the magnetite fluorescent Fe3O4@SiO2-TPED-BODIPY and Fe3O4@SiO2-TMPTA-BODIPY nano-sensors by Cr(VI) were completed in first 5 and 3 min. Respectively. These features provide potential uses of BODIPY functionalized magnetite fluorescent nano-sensors (Fe3O4@SiO2-TPED-BODIPY and Fe3O4@SiO2-TMPTA-BODIPY) as a new class of non-toxic sensors for environmental applications. Graphical Abstract.

Real-time Monitoring of Discrete Synaptic Release Events and Excitatory Potentials within Self-reconstructed Neuromuscular Junctions.

Chemical synaptic transmission is central to the brain functions. In this regard, real-time monitoring of chemical synaptic transmission during neuronal communication remains a great challenge. In this work, in vivo-like oriented neural networks between superior cervical ganglion (SCG) neurons and their effector smooth muscle cells (SMC) were assembled in a microfluidic device. This allowed amperometric detection of individual neurotransmitter release events inside functional SCG-SMC synapse with carbon fiber nanoelectrodes as well as recording of postsynaptic potential using glass nanopipette electrodes. The high vesicular release activities essentially involved complex events arising from flickering fusion pores as quantitatively established based on simulations. This work allowed for the first time monitoring in situ chemical synaptic transmission under conditions close to those found in vivo, which may yield important and new insights into the nature of neuronal communications.

State-of-the-art nanosensors and kits for the detection of antibiotic residues in milk and dairy products.

Antibiotic resistance is increasingly seen as a future concern, but antibiotics are still commonly used in animals, leading to their accumulation in humans through the food chain and posing health risks. The development of nanomaterials has opened up possibilities for creating new sensing strategies to detect antibiotic residues, resulting in the emergence of innovative nanobiosensors with different benefits like rapidity, simplicity, accuracy, sensitivity, specificity, and precision. Therefore, this comprehensive review provides pertinent and current insights into nanomaterials-based electrochemical/optical sensors for the detection of antibitic residues (ANBr) across milk and dairy products. Here, we first discuss the commonly used ANBs in real products, the significance of ANBr, and also their binding/biological properties. Then, we provide an overview of the role of using different nanomaterials on the development of advanced nanobiosensors like fluorescence-based, colorimetric, surface-enhanced Raman scattering, surface plasmon resonance, and several important electrochemical nanobiosensors relying on different kinds of electrodes. The enhancement of ANB electrochemical behavior for detection is also outlined, along with a concise overview of the utilization of (bio)recognition units. Ultimately, this paper offers a perspective on the future concepts of this research field and commercialized nanomaterial-based sensors to help upgrade the sensing techniques for ANBr in dairy products.

Nanotechnology, a frontier in agricultural science, a novel approach in abiotic stress management and convergence with new age medicine-A review.

Climate change imposes various environmental stresses which substantially impact plant growth and productivity. Salinity, drought, temperature extremes, heavy metals, and nutritional imbalances are among several abiotic stresses contributing to high yield losses of crops in various parts of the world, resulting in food insecurity. Many interesting strategies are being researched in the attempt to improve plants' environmental stress tolerance. These include the application of nanoparticles, which have been found to improve plant function under stress situations. Nanotechnology will be a key driver in the upcoming agri-tech and pharmaceutical revolution, which promises a more sustainable, efficient, and resilient agricultural and medical system Nano-fertilizers can help plants utilise nutrients more efficiently by releasing nutrients slowly and sustainably. Plant physiology and nanomaterial features (such as size, shape, and charge) are important aspects influencing the impact on plant growth. Here, we discussed the most promising new opportunities and methodologies for using nanotechnology to increase the efficiency of critical inputs for crop agriculture, as well as to better manage biotic and abiotic stress. Potential development and implementation challenges are highlighted, emphasising the importance of designing suggested nanotechnologies using a systems approach. Finally, the strengths, flaws, possibilities, and risks of nanotechnology are assessed and analysed in order to present a comprehensive and clear picture of the nanotechnology potentials, as well as future paths for nano-based agri-food applications towards sustainability. Future research directions have been established in order to support research towards the long-term development of nano-enabled agriculture and evolution of pharmaceutical industry.

Unraveling the hazardous impact of diverse contaminants in the marine environment: Detection and remedial approach through nanomaterials and nano-biosensors.

Marine pollution is one of the most underlooked forms of pollution as it affects most aquatic lives and public health in the coastal area. The diverse form of the hazardous pollutant in the marine ecosystem leads the serious genetic level disorders and diseases which include cancer, diabetes, arthritis, reproductive, and neurological diseases such as Parkinson's, Alzheimer's, and several microbial infections. Therefore, a recent alarming study on these pollutants, the microplastics have been voiced out in many countries worldwide, it was even found to be in the human placenta. In recent times, nanomaterials have demonstrated their potential in the detection and remediation of sensitive contaminants. In this review, we presented a comprehensive overview of the source, and distribution of diverse marine pollution on both aquatic and human health by summarizing the concentration of diverse pollutions (heavy metals, pesticides, microbial toxins, and micro/nano plastics) in marine samples such as soil, water, and seafood. Followed by emphasizing its ecotoxicological impact on aquatic animal life and coastal public health. Also discussed are the applicability and advancements of nanomaterials and nano-based biosensors in the detection, prevention, and remediation of diverse pollution in the marine ecosystem.

Nanoremediation technologies for sustainable remediation of contaminated environments: Recent advances and challenges.

A major and growing concern within society is the lack of innovative and effective solutions to mitigate the challenge of environmental pollution. Uncontrolled release of pollutants into the environment as a result of urbanisation and industrialisation is a staggering problem of global concern. Although, the eco-toxicity of nanotechnology is still an issue of debate, however, nanoremediation is a promising emerging technology to tackle environmental contamination, especially dealing with recalcitrant contaminants. Nanoremediation represents an innovative approach for safe and sustainable remediation of persistent organic compounds such as pesticides, chlorinated solvents, brominated or halogenated chemicals, perfluoroalkyl and polyfluoroalkyl substances (PFAS), and heavy metals. This comprehensive review article provides a critical outlook on the recent advances and future perspectives of nanoremediation technologies such as photocatalysis, nano-sensing etc., applied for environmental decontamination. Moreover, sustainability assessment of nanoremediation technologies was taken into consideration for tackling legacy contamination with special focus on health and environmental impacts. The review further outlines the ecological implications of nanotechnology and provides consensus recommendations on the use of nanotechnology for a better present and sustainable future.

Bio-nanocomposite based highly sensitive and label-free electrochemical immunosensor for endometriosis diagnostics application.

In this research, for the first time, a bio-nanocomposites based highly sensitive and label-free electrochemical immunosensor is reported with the aim of endometriosis diagnostics application. Multiwalled carbon nanotube and magnetite nanoparticle (MWCNT-Fe3O4) was dispersed in chitosan (CS) to fabricate a bio-nanocomposite to immobilize very monoclonal specific antibody (via cross-linking using glutaraldehyde) for selective electrochemical immuno-sensing of carbohydrate antigen 19-9 (CA19-9), a potential biomarker for endometriosis diagnostics. Well-characterized Anti-AbsCA19-9/CS-MWCNT-Fe3O4 immune-electrode fabricated on glassy carbon electrode (GCE) successfully detect CA 19-9 and exhibited a high sensitivity as (2.55 µA pg-1 cm-1), a detection limit of 0.163 pg mL-1, detection range from 1.0 pg mL-1 to 100 ng mL-1. Our fabricated electrochemical AbsCA19-9/CS-MWCNT-Fe3O4 immunosensor performed CA19-9 sensing in physiological range and at a very level which suggest it application for early-stage diagnostics, diseases monitoring, and optimization of therapy. To claim the clinical application, our sensor was tested using real samples and sensing performance was validated using enzyme-linked immune-sorbent assay (ELISA). The results of the studies projected AbsCA19-9/CS-MWCNT-Fe3O4 electrochemical CA19-9 immunosensor as a potential and affordable alternate of conventional techniques like ELISA. We believe that our fabricated sensor can be the plane of a disease's management program due to affordable, rapid, label-free, and sensitive detection of a targeted biomarker.

Binary fingerprints at fluctuation-enhanced sensing.

We have developed a simple way to generate binary patterns based on spectral slopes in different frequency ranges at fluctuation-enhanced sensing. Such patterns can be considered as binary "fingerprints" of odors. The method has experimentally been demonstrated with a commercial semiconducting metal oxide (Taguchi) sensor exposed to bacterial odors (Escherichia coli and Anthrax-surrogate Bacillus subtilis) and processing their stochastic signals. With a single Taguchi sensor, the situations of empty chamber, tryptic soy agar (TSA) medium, or TSA with bacteria could be distinguished with 100% reproducibility. The bacterium numbers were in the range of 2.5 × 10(4)-10(6). To illustrate the relevance for ultra-low power consumption, we show that this new type of signal processing and pattern recognition task can be implemented by a simple analog circuitry and a few logic gates with total power consumption in the microWatts range.

Execution of aggregation-induced emission as nano-sensors for hypochlorite detection and application for bioimaging in living cells and zebrafish.

Hypochlorite (ClO-) could be used as a diagnostic marker for inflammation and related diseases. Although there have been many reports on probes for ClO- imaging, there was still a lack of specificity and anti-interference ability. Herein, carbazole (NEC) and tetraphenylethylene (TPE) equipped with thiobarbituric acid (TBA), NEC-TBA and TPE-TBA, were synthesized and used as a fluorescence biosensor for monitoring ClO- with aggregation-induced emission (AIE) effect. we identified that TPE-TBA, with formed nanoparticles in the mean grain size at 76 nm (5 µM), was a superior probe to target ClO- over other analytes with fluorescence "turn off" strategy. Subsequently, to explore the bioimaging application, TPE-TBA was able to sense exogenous ClO- in living HeLa cells through fluorescence imaging. In zebrafish model, TPE-TBA effectively captured exogenous ClO- in the entire organization of zebrafish. Overall, these AIE-based probes merit further development as organism targeting ClO- sensors.

Exosomal biomarkers for cancer diagnosis and patient monitoring.

Introduction: In recent years, extensive research has been conducted on using exosomes as biomarkers for cancer detection. Exosomes are 40-150 nm-sized extracellular vesicles released by all cell types, including tumor cells. Exosomes are stable in body fluids due to their lipid bilayer member and often contain DNA, RNA, and proteins. These exosomes can be harvested from blood, plasma, serum, urine, or saliva and analyzed for tumor-relevant mutations. Thus, exosomes provide an alternative to current methods of tumor detection.Areas covered: This review discusses the use of exosomal diagnostics in various tumor types as well as their examination in various clinical trials. The authors also discuss the limitations of exosome-based diagnostics in the clinical setting and provide examples of several studies in which the development and usage of microfluidic chips and nano-sensing devices have been utilized to address these obstacles.Expert commentary: In recent years, exosomes and their contents have exhibited potential as novel tumor detection markers despite the labor involved in their harvest and isolation. Despite this, much work is being done to optimize exosome capture and analysis. Thus, their roles as biomarkers in the clinical setting appear promising.

Nano-enabled biosensing systems for intelligent healthcare: towards COVID-19 management.

Biosensors are emerging as efficient (sensitive and selective) and affordable analytical diagnostic tools for early-stage disease detection, as required for personalized health wellness management. Low-level detection of a targeted disease biomarker (pM level) has emerged extremely useful to evaluate the progression of disease under therapy. Such collected bioinformatics and its multi-aspects-oriented analytics is in demand to explore the effectiveness of a prescribed treatment, optimize therapy, and correlate biomarker level with disease pathogenesis. Owing to nanotechnology-enabled advancements in sensing unit fabrication, device integration, interfacing, packaging, and sensing performance at point-of-care (POC) has rendered diagnostics according to the requirements of disease management and patient disease profile i.e. in a personalized manner. Efforts are continuously being made to promote the state of art biosensing technology as a next-generation non-invasive disease diagnostics methodology. Keeping this in view, this progressive opinion article describes personalized health care management related analytical tools which can provide access to better health for everyone, with overreaching aim to manage healthy tomorrow timely. Considering accomplishments and predictions, such affordable intelligent diagnostics tools are urgently required to manage COVID-19 pandemic, a life-threatening respiratory infectious disease, where a rapid, selective and sensitive detection of human beta severe acute respiratory system coronavirus (SARS-COoV-2) protein is the key factor.

A dual-response ratiometric fluorescent sensor by europium-doped CdTe quantum dots for visual and colorimetric detection of tetracycline.

Residues in animal food and drinking water caused by the abuse of antibiotics lead to cell resistance and many chronic diseases in the human body. Therefore, it has become an inevitable trend to develop a fast, easy-to-use, on-site/real-time visualization method for the detection of antibiotics. Herein, we report a dual-response ratiometric fluorescence sensor which is fabricated by chelating europium ions (Eu3+) onto cadmium telluride quantum dots (CdTe QDs) for real-time and visible detection of tetracycline (TC). With the TC addition, the fluorescence of probe can be seen by the naked eye, from green to yellow and finally to red, exhibiting a dosage-sensitive and broad-chromatic detection strategy for TC. The fluorescence intensity ratio of I616/I512 of Eu/CdTe QDs sensor displays a good linear relation to TC concentrations in the range of 0-80 µM with a limit of detection (LOD) of 2.2 nM. In addition, the sensor can visually detect 200 nM TC in actual samples, which is lower than the maximum residue limit (MRL) of the safety standard. The methodology reported here opens a window toward the real applications of fluorescent and shows the wide applicability in pursuing the concepts simple, rapid, visual, and real-time for food safety and environmental protection.

Nanomaterials-Tools, Technology and Methodology of Nanotechnology Based Biomedical Systems for Diagnostics and Therapy.

Nanomedicine helps to fight diseases at the cellular and molecular level by utilizing unique properties of quasi-atomic particles at a size scale ranging from 1 to 100 nm. Nanoparticles are used in therapeutic and diagnostic approaches, referred to as theranostics. The aim of this review is to illustrate the application of general principles of nanotechnology to select examples of life sciences, molecular medicine and bio-assays. Critical aspects relating to those examples are discussed.