Quantification of Chlorpyrifos Residues in Water under Thermodynamically Favorable Electrodics Using the f-MWCNT/N-(2-C2H5O) ED(CH3COONa)3 Composite of Superior Selectivity.

Researchers are continually seeking potential alternatives to develop water quality sensors with higher selectivity to obtain the desired performance during real-time deployment. Quantification technologies involving interface materials of distinguishing capacity at elevated matrix complexity are desirable. However, there remains a challenge in designing suitable techniques, methodologies, and appropriate validations to support the grounds for the selection of interface materials of enhanced selectivity. The ability to monitor chlorpyrifos in analytical and commercial grade compounds and in the water matrix using an interface material of suitable states is the focus of this work. Herein, N-(2-hydroxyethyl) ethylenediamine triacetic acid trisodium (N-(2-C2H5O) ED(CH3COONa)3) incorporated with functionalized multiwalled carbon nanotube (f-MWCNT) is reported to provide thermodynamically favorable charge transfer for the quantification of chlorpyrifos residues under varying internal and external conditions with appropriate validations using density functional theory (DFT) and high-performance liquid chromatography (HPLC). The sensor exhibited excellent figures of merit such as limit of detection (LOD) and limit of quantitation (LOQ) of 9.7 pM and 29.4 pM, respectively.

Sensor-on-Microtips: Design and Development of Hydrothermally Grown ZnO on Micropipette Tips as a Modified Working Electrode for Detection of Glucose.

Miniaturization of electrochemical components has become less common in the last decade, with the focus predominantly being the design and development of state-of-the-art microelectrodes for achieving small volume analysis of samples. However, such microelectrodes involve cumbersome processing procedures to convert the base material for the required application. A potential paradigm shift in such miniaturization could be achieved by using cheaper alternatives such as plastics to build electrochemical components, such as micropipette tips made of polypropylene, which are commercially available at ease. Hence, this work presents the design of an electrochemical working electrode based upon a micropipette tip, involving minimal processing procedures. Furthermore, such a working electrode was realized by sputtering silver onto a bare micropipette tip using a radio-frequency sputtering technique, to obtain electrical contacts on the tip, followed by hydrothermal growth of ZnO, which acted as the active electrode material. The ZnO nanostructures grown on the micropipette tip were characterized for their morphology and surface properties using a scanning electron microscope (SEM), laser microscope, Raman spectrometer, and X-ray photoelectron spectrometer (XPS). The developed micropipette tip-based electrode was then used as the working electrode in a three-electrode system, wherein its electrochemical stability and properties were analyzed using cyclic voltammetry (CV). Furthermore, the above system was used to detect glucose concentrations of 10-200 µM, to evaluate its sensing properties using amperometry. The developed working electrode exhibited a sensitivity of 69.02 µA/µM cm-2 and limit of detection of 67.5 µM, indicating the potential for using such modified micropipette tips as low-cost miniaturized sensors to detect various bio-analytes in sample solutions.

Gas Sensing of Laser-Produced Hybrid TiO2-ZnO Nanomaterials under Room-Temperature Conditions.

The preparation method can considerably affect the structural, morphological, and gas-sensing properties of mixed-oxide materials which often demonstrate superior photocatalytic and sensing performance in comparison with single-metal oxides. In this work, hybrids of semiconductor nanomaterials based on TiO2 and ZnO were prepared by laser ablation of Zn and Ti plates in water and then tested as chemiresistive gas sensors towards volatile organics (2-propanol, acetaldehyde, ethanol, methanol) and ammonia. An infrared millisecond pulsed laser with energy 2.0 J/pulse and a repetition rate of 5 Hz was applied to Zn and Ti metal targets in different ablation sequences to produce two nano-hybrids (TiO2/ZnO and ZnO/TiO2). The surface chemistry, morphology, crystallinity, and phase composition of the prepared hybrids were found to tune their gas-sensing properties. Among all tested gases, sample TiO2/ZnO showed selectivity to ethanol, while sample ZnO/TiO2 sensed 2-propanol at room temperature, both with a detection limit of ~50 ppm. The response and recovery times were found to be 24 and 607 s for the TiO2/ZnO sensor, and 54 and 50 s for its ZnO/TiO2 counterpart, respectively, towards 100 ppm of the target gas at room temperature.

Real-time detection of imidacloprid residues in water using f-MWCNT/EDTA as energetically suitable electrode interface.

Real-time assessment of an active ingredient imidacloprid in the water matrix is critically momentous in monitoring the levels of pesticide contaminants in water bodies. Conventional approaches predominantly deal with the detection of imidacloprid, relying on the purified analytical grade compound. Herein, we report an organic/inorganic composite (f-MWCNT/EDTA) integrated electrochemical sensor for the real-time analysis of analytical grade imidacloprid and extended the performance evaluation in agriculture-purpose imidacloprid compound used commercially by farmers. The choice of the electrode interface significantly supports the electrocatalytic activity towards imidacloprid due to the presence of appropriate energy levels, which are favourable for charge transfer processes validated with Density Functional Theory (DFT) calculations. Further, the performance of the sensor was evaluated in the aquatic environment using river water samples procured from seven different sampling sites and in tap water. The organic/inorganic composite-based electrochemical sensor shows a detection limit of 3.1 × 10-3 pM and three significant wide linear concentration ranges of 0.001-0.05 nM, 0.001-0.04 µM, and 0.001-0.004 mM with apparent interferent resistance. This work paves the way for the real-time environmental monitoring and quantification of imidacloprid by utilizing the highly effective f-MWCNT/EDTA composite catalytic layer.

Iron Oxide Nanoparticles: A Review on the Province of Its Compounds, Properties and Biological Applications.

Materials science and technology, with the advent of nanotechnology, has brought about innumerable nanomaterials and multi-functional materials, with intriguing yet profound properties, into the scientific realm. Even a minor functionalization of a nanomaterial brings about vast changes in its properties that could be potentially utilized in various applications, particularly for biological applications, as one of the primary needs at present is for point-of-care devices that can provide swifter, accurate, reliable, and reproducible results for the detection of various physiological conditions, or as elements that could increase the resolution of current bio-imaging procedures. In this regard, iron oxide nanoparticles, a major class of metal oxide nanoparticles, have been sweepingly synthesized, characterized, and studied for their essential properties; there are 14 polymorphs that have been reported so far in the literature. With such a background, this review's primary focus is the discussion of the different synthesis methods along with their structural, optical, magnetic, rheological and phase transformation properties. Subsequently, the review has been extrapolated to summarize the effective use of these nanoparticles as contrast agents in bio-imaging, therapeutic agents making use of its immune-toxicity and subsequent usage in hyperthermia for the treatment of cancer, electron transfer agents in copious electrochemical based enzymatic or non-enzymatic biosensors and bactericidal coatings over biomaterials to reduce the biofilm formation significantly.

Fabrication of GQD-Electrodeposited Screen-Printed Carbon Electrodes for the Detection of the CRP Biomarker.

The traditional three-electrode electrochemical system used in the development of biosensors for detecting various biomarkers of interest necessitates the use of bulk electrodes, which precludes the deployment of handheld electrochemical devices in clinical applications. Affordable screen-printed carbon electrodes (SPCEs) modified with functional interfaces are being developed to enhance the sensitivity of a compact sensing system as a whole. In this work, SPCEs were fabricated on an overhead projection (OHP) sheet in three different active areas of 2 × 2, 3 × 3, and 4 × 4 mm2 using a screen printing technique, and then ∼2 nm sized graphene quantum dots (GQDs) were electrodeposited over the SPCE surface to add functionality for the detection of ultralow levels of one of the cardiac biomarkers, C-reactive protein (CRP). The proposed mediator-dependent voltammetric biosensor exhibited good sensitivity, a low detection limit, and a linear range of 2.45 µA ng-1 mL-1 cm-2, 0.036 ng mL-1, and 0.5-10 ng mL-1, respectively. The fabricated SPCE/GQDs/anti-CRP biosensor could rapidly detect CRP in less than 25 s. The intra- and interassays were performed with five sensor strips, which showed a minimum standard deviation of 1.85 and 2.8%, respectively. The SPCE/GQDs/anti-CRP electrode was used to detect CRP concentrations in a ringer lactate solution. Thus, the developed biosensor has all of the characteristics such as rapidity, inexpensive disposable electrodes, miniaturization, and a lower detection limit needed to evolve as a point-of-care (PoC) application.

Photoluminescence-Based Bioassay With Cysteamine-Capped TiO2 Nanoparticles for the Selective Recognition of N-Acyl Homoserine Lactones.

Currently available diagnostic procedures for infections are laborious and time-consuming, resulting in a substantial financial burden by increasing morbidity, increased costs of hospitalization, and mortality. Therefore, innovative approaches to design diagnostic biomarkers are imperative to assist in the rapid and sensitive diagnosis of microbial infections. Acyl homoserine lactones (AHLs) are ubiquitous bacterial signaling molecules that are found to be significantly upregulated in infected sites. In this pioneering work, we have developed a simple photoluminescence-based assay using cysteamine-capped titanium oxide (TiO2) nanoparticles for AHL detection. The PL intensity variation of the oxygen defect state of TiO2 was used for the biosensing measurements. The bioassays were validated using two well-studied AHL molecules (C4-HSL and 3-oxo-C12 HSL) of an important human pathogen, Pseudomonas aeruginosa. The developed system has a maximum relative response of 98%. Furthermore, the efficacy of the system in simulated host urine using an artificial urine medium showed a linear detection range of 10-160 nM. Also, we confirmed the relative response and specificity of the system in detecting AHLs produced by P. aeruginosa in a temporal manner.

ROI-based medical image watermarking for accurate tamper detection, localisation and recovery.

Smart healthcare systems play a vital role in the current era of Internet of Things (IoT) and Cyber-Physical Systems (CPS); i.e. Industry 4.0. Medical data security has become the integral part of smart hospital applications to ensure data privacy and patient data security. Usually, patient medical reports and diagnostic images are transferred to the specialist physician in other hospitals for effective diagnostics. Therefore, the transmission of medical data over the internet has attained significant interest among many researchers. The three main challenges associated with the e-healthcare systems are the following: (1) ensuring authentication of medical information; (2) transmission of medical image and patient health record (PHR) should not cause data mismatch/detachment; and (3) medical image should not be modified accidentally or intentionally as they are transmitted over the insecure medium. Thus, it is highly essential to ensure the integrity of the medical image, especially the region of interest (ROI) before taking any diagnostic decisions. Watermarking is a well-known technique used to overcome these challenges. The current research work has developed a watermarking algorithm to ensure integrity and authentication of the medical data and image. In this paper, a novel watermarking algorithm is designed based on Integer Wavelet Transform (IWT), combined chaotic map, recovery bit generation and SHA-256 to address the objective as mentioned earlier. The paper's significant contribution is divided into four phases, namely, watermark generation and data embedding phase, authentication phase, tamper detection phase and localisation and lossless recovery phase. Experiments are carried out to prove that the developed IWT-based data embedding scheme offers high robustness to the data embedded in region of non-interest (RONI), detects and localises the tampered blocks inside ROI with 100% accuracy and recovers the tampered segments of ROI with zero MSE. Further, a comparison is made with the state-of-art schemes to verify the sternness of the developed system.

A non-enzymatic electrochemical biosensor for the detection of formalin levels in fishes: Realization of a novel comparator effect based on electrolyte.

Formalin has been used as the preservative of fishes in the concentration range of 15-25 mgL-1. However, there have been a high frequency of violations in the optimum use of formalin levels. The consumption of fishes treated with excessive formalin levels leads to nasopharynx, leukaemia and sinonasal cancer and there is a huge demand for the development of formalin sensor. Conventional formalin sensors such as chromogenic and mass balance sensors fall short in real-time analysis due to the lack of specificity and sensitivity in the interference medium. In this context, it has been emphasized to develop a non-enzymatic electrochemical biosensor with microwave synthesized CdS nanoparticles as a nanointerface owing to its surface limited kinetics. NaCl of 1 mM was considered as an electrolyte solution in the present study. Dynamic sensing characteristics with varying formalin levels of 5-50 mgL-1 was studied in three different concentration ranges as 5-15 mgL-1 (concentration of formalin < NaCl; conversion of formalin to formic acid), 20-30 mgL-1 (concentration of formalin âˆ¼ NaCl; equilibrium between the oxidative and reductive product), 35-50 mgL-1 (concentration of formalin > NaCl; complete oxidation of formic acid to CO2). Hence, with the exhibition of such a dynamic sensitivity based on electrolyte, the developed biosensor acts as an electrochemical comparator showcasing a switch-like behaviour in detecting formalin levels. The threshold concentration of formalin required for the comparator effect was found to be 14.845 mgL-1. The developed biosensor, most essentially, exhibited a versatility in quantifying formalin levels in real-time fish samples.

A photoluminescence biosensor for the detection of N-acyl homoserine lactone using cysteamine functionalized ZnO nanoparticles for the early diagnosis of urinary tract infections.

A urinary tract infection (UTI) is a recurrent infection that requires timely diagnosis and appropriate treatment. Conventional urinalysis methods are laborious and time-consuming, and lack sensitivity and specificity. In this context, photoluminescence (PL)-based biosensors have gained more attention due to their fast response time, and enhanced sensitivity and specificity. In relation to this, a PL-based biosensor was developed using ZnO nanoparticles obtained via a microwave-assisted process functionalized with cysteamine (ZnO-Cys) to detect the quorum sensing signalling molecules of Gram-negative bacteria, N-acyl-homoserine lactones (AHLs). These AHLs are involved in bacterial communication and are responsible for activating virulence and pathogenicity. Biosensing measurements based on PL intensity variations corresponding to the O2 acceptor defect level of ZnO with reference to ZnO-Cys were considered. A maximum sensitivity of 97% was achieved in the detection of AHL. The linear detection range of the developed biosensor was 10-120 nM in artificial urine media (AUM). The effect of pH on the sensitivity of the biosensor in AUM was also investigated and reported. The developed sensor was validated using the AHLs produced by Pseudomonas aeruginosa (MCC3101) in real-time analysis, which further confirmed the overall specificity and sensitivity.

Electrochemical Detection of Imidacloprid Using Cu-rGO Composite Nanofibers Modified Glassy Carbon Electrode.

The fabrication of electrochemical sensor for the ultra-low-level detection and quantification of Imidacloprid (IMD) in soil is one of the major challenges in real-time analysis. Herein, a three-electrode system for sensing IMD at low levels has been developed using Cu-rGO nanofiber composite modified glassy carbon working electrode, Ag/AgCl reference and platinum wire counter electrodes. In the presence of IMD, a significant enhancement in voltammetric current responses were observed at 0.506, 0.375 and 0.181 V due to [Formula: see text] redox complexes. The developed sensor exhibited sensitivity of 0.325 µA µM-1 with the limit of detection, quantification and repeatability of 2.511 nM, 7.533 nM and 0.28 RSD% respectively. The fabricated sensor could detect IMD with swift response time of less than 5 s. Further, the fabricated electrode was successfully employed to quantify the levels of IMD in soil samples and the results are reported.

Functionalized Graphene Quantum Dot Interfaced Electrochemical Detection of Cardiac Troponin I: An Antibody Free Approach.

According to the World Health Organization (WHO), cardiovascular disease (CVD) is the leading cause of death in the world every year. The design and development of biosensors for the detection of CVD markers could be one of the major contributions of the scientific community to society. In this context, acetic acid functionalized graphene quantum dots (fGQDs) were used as an interface for the electrochemical detection of cardiac Troponin I (cTnI). The interaction of cTnI with fGQDs for the early diagnosis of acute myocardial infarction was investigated using cyclic voltammetry (CV) and amperometry. The carbodiimide conjugation between the N-H group of cTnI and the functionalized COOH group on GQDs enabled the detection of cTnI biomarker. The same sensing mechanism was confirmed using Fourier Transform Infrared Spectrometry (FTIR). The fGQDs modified Au electrode showed remarkable electrocatalytic oxidation of cTnI with good stability and sensitivity over a linear range of 0.17 to 3 ng mL-1 and a low detection limit of 0.02 ng mL-1. Bland-Altman plots substantiate a bias between the intra-/inter-cTnI assay and calibrated cTnI assay with 95% limits of agreement (mean difference ± 1.96 SD). The aim of this study is to describe an innovative method to detect cardiac biomarker cTnI and provide preliminary data on its diagnostic capacity. At the same time, its applicability in clinical setting will have to be validated with a significant number of samples collected from patients.

Highly crystalline {010} facet grown α-MoO3 nanobelts for resistive sensing of n-butanol vapor at room temperature.

The present work is aimed at developing an n-butanol sensor based on the chemi-resistive principle using MoO3 nanostructures as a sensing element. Highly ordered free-standing α-MoO3 nanobelts were synthesized using hydrothermal technique. The synthesis parameters adapted in the present work have paved a way in obtaining distinct MoO3 nanostructure with minimal process time as compared with the earlier reports. Initially, the formation of monoclinic crystals with an end centered lattice of ß-Mo9O26 was observed, which then is transformed into orthorhombic α-MoO3 on calcination at 450 °C for 5 h. XPS profiles of the nanobelts revealed the presence of molybdenum and oxygen in a stoichiometric ratio of 2.6. Penta- and hexa-coordinated defect centers of Mo5+ and oxygen vacancies were observed from the photoluminescence spectra. The nanobelts respond to n-butanol vapors at room temperature with a 75-fold signal increase and response-recovery times of 17 & 10 s, respectively. The lowest detection limit is 1 ppm. The influence of relative humidity on the sensing response was also studied. Graphical abstract.

Smart supramolecular gels of enolizable amphiphilic glycosylfuran.

The implementation of a novel approach in the development of stimuli responsive supramolecular gels is an important objective that challenges material chemists and biologists in order to access an exclusively new category of smart materials. In this report, non-toxic, bio-based amphiphilic glycosylfurans were designed and synthesized using a biocatalyst, Novozyme 435, an immobilized lipase B from Candida antarctica. The self-assembly of these compounds generated oleogels and hydrogels. To our delight, these bio-based amphiphilic glycosylfurans furnished an in situ stimuli responsive hydrogel with simultaneous encapsulation of various biologically relevant molecules and ions. For the first time we are reporting hydrogelation via in situ molecular tuning followed by a self-sorting mechanism. The sol-to-gel transition in the reported smart hydrogel was observed by the addition of acidic buffer of pH 4.0, which could be potentially used for the stimuli responsive delivery of a signalling molecule, H2S and other biomolecules that regulate many physiological and pathological processes.

NiO x Nanoflower Modified Cotton Fabric for UV Filter and Gas Sensing Applications.

Integration of multifunctional nanomaterials with textiles could be a significant value addition to the bright future of the growing technology "Technical Textiles". Development of textiles with antielectromagnetic radiation and in particular antiultraviolet features could be one of the best solutions to the ozone depletion induced ultraviolet pollution of the environment, which is a major concern in the context of surging skin cancer cases. In this background, multifunctional nanoflower structured partial hydroxide nickel oxide (NiO x) was grown on cotton fabric using a chemical bath deposition technique for the development of UV filter and flexible gas/chemical sensor. X-ray diffraction patterns of bare and NiO x modified cotton fabrics confirmed the micro and poly crystalline nature, respectively. Field emission scanning electron microscopic images revealed the growth of 3D green button chrysanthemum flower-like morphology on the surface of cotton fabric. In addition, X-ray photoelectron spectra revealed the presence of nickel, carbon, and oxygen elements in the NiO x modified cotton cellulose. The increase in hydrophobic nature of surface-treated fabric was observed using a goniometer. A differential scanning calorimeter trace for bare and surface modified cotton fabrics exhibited endothermic behavior at the characteristic onset temperature. The results of thermogravimetric analysis revealed the enhanced thermal stability of up to 800 °C for the surface-treated fabric compared to bare cotton. Further, the ultraviolet protection factor (UPF) of the NiO x nanoflower modified cotton fabric was measured using an in vitro method following the AATCC 183:2004 standard using a UV transmittance analyzer. The enhanced absorbance of ultraviolet rays at 388 nm resulted in the UPF of 2000. The chemical/gas sensing features of the surface modified textile samples were investigated using the homemade gas testing chamber. NiO x modified fabric showed a selective response of 12431 toward trimethylamine at room temperature.

Methylglyoxal - An emerging biomarker for diabetes mellitus diagnosis and its detection methods.

Diabetes Mellitus (DM) is one among the supreme metabolic issues observed in history since 3000 BCE and has gained much interest recently due to the increasing number of diabetic cases every year. Glucose is considered as the most iconic biomarker for diabetes detection, and fluctuations in its levels are related to different stages of DM. However, methylglyoxal (MG) is evolving as a diabetes marker since it plays a significant role in biological processes Apart from DM, MG causes several metabolic irregularities like hypertension, neuropathy, nephropathy, oxidative stress. Besides, MG is a predominant precursor of advanced glycation end products (AGEs), which result in protein dysfunction, glycation of vascular tissues and aging. In this background, detection of MG has much importance, and the design of smart models is desirable. MG formation, detoxification, and its glycation effects have paved the way for the development of detection strategies which are described in detail here. The direct and indirect methods of MG measurement have been established in the past. At present, techniques like high-performance liquid chromatography, gas chromatography-mass spectrometry, enzyme-linked immunosorbent assay, capillary electrophoresis, electrochemical biosensors have been used to quantify MG present in the samples. Here, we have tried to correlate the function of MG and detection strategies to explain the major challenges posed towards implementation of easy, efficient and accurate standardization.

Development of an acetone sensor using nanostructured Co3O4 thin films for exhaled breath analysis.

In recent times, the development of breath sensors for the detection of Diabetic Keto-Acidosis (DKA) has been gaining prominent importance in the field of health care and advanced diagnostics. Acetone is one of the prominent biomarkers in the exhaled breath of persons affected by DKA. In this background, nanostructured cobalt oxide sensing elements were fabricated using a spray pyrolysis technique at different deposition temperatures (473 to 773 K in steps of 100 K) towards the fabrication of an acetone sensor. The influence of deposition temperature on the various properties of the nanostructured cobalt oxide thin films was investigated. Formation of cubic spinel phase cobalt oxide was confirmed from the structural analysis. The shifting of plane orientation from (3 1 1) to (2 2 0) at 773 K deposition temperature revealed the migration of cobalt atoms to the highly favorable energy positions. Further, the downshifted peak absorption wavelength and upshifted PL profile at higher deposition temperature confirmed the migration of cobalt ions. The sensor fabricated at higher deposition temperature (773 K) showed a sensing response of 235 at room temperature towards 50 ppm of acetone. Also, the fabricated sensor showed a lower detection limit (LOD) of 1 ppm with the response-recovery times of 6 and 4 s, respectively. The LOD reported here is lower than the minimum threshold level (1.71 ppm) signifying the presence of DKA.

Fabrication of an electrochemical biosensor with ZnO nanoflakes interface for methylglyoxal quantification in food samples.

Increased consumption of fried foods such as grilled chicken contains elevated levels of methylglyoxal (MG), which is associated with diabetes mellitus. Hence, in this work, glyoxalase 1(GLO 1) based, zinc oxide (ZnO) flakes interfaced mediator free electrochemical biosensor was developed to detect MG in grilled chicken. ZnO flakes were synthesized by direct precipitation method. X-ray diffractometer and field emission scanning electron microscope were used to study the structural and morphological characteristics of ZnO flakes. The immobilization of GLO 1 on Pt/ZnO flakes modified electrode was confirmed by Fourier transform infrared spectroscopy. Cyclic voltammetric and amperometric studies were carried out using Pt/ZnO flakes/GLO 1 working electrode. The developed biosensor exhibited linear range of 0.6-2.0 µM, sensitivity of 0.281 µA µM-1, LOD of 9 nM with a response time of <4 s and shelf life of 18 days (89%).

Networked medical data sharing on secure medium - A web publishing mode for DICOM viewer with three layer authentication.

Growing demand for e-healthcare across the globe has raised concerns towards the secure and authentication enhanced medical image sharing. One of the services offered by health informatics in hospitals include an user interface through the Local Area Network (LAN) for enabling storage and access of medical records. In this paper, a security enhanced DICOM image sharing over a LAN addressing confidentiality, integrity and authentication has been proposed. Initially, the AES encrypted patient history was combined along with the thumb impression and Quick Response (QR) code of patient ID as watermark. This watermark was encrypted employing Integer Wavelet Transform (IWT), chaotic map and attractors with confusion-diffusion operations. Further, the encrypted watermark was embedded in the selected Region Of Non-Interest (RONI) pixels of DICOM image. Username & unique password credentials, Face identification and FPGA generated One Time Password (OTP) form the three layer authentication scheme for secure DICOM image access through the LAN. Web publishing medium of storing secured DICOM images in cloud has also been addressed in this work. To validate the proposed hybrid crypto-watermarking system, parameters such as key sensitivity, key space, correlation, entropy, histogram, cropping attack, Mean Square Error (MSE), Peak Signal to Noise Ratio (PSNR) and Structural Similarity Index Metric (SSIM) were performed and the results obtained have proved the strength of the proposed algorithm against brute force, statistical and cropping attacks.

Nanotechnology-based electrochemical detection strategies for hypertension markers.

Hypertension results due to dysfunction of different metabolic pathways leading to the increased risk of cerebral ischemia, atherosclerosis, cardiovascular and inflammatory disorders. Hypertension has been considered a one of the major contributors to metabolic syndrome and is often referred to as a 'silent killer'. Its incidence is on the rise across the globe owing to the drastic life style changes. The diagnosis of hypertension had been traditionally carried out through measurement of systolic and diastolic blood pressure but in most cases, this form of diagnosis is too late and the disease has already caused organ damage. Therefore, early detection of hypertension by monitoring subtle changes in specific biochemical markers from body fluids can minimize the risk of organ damage. However, a single marker may be insufficient for accurate diagnosis of hypertension thereby necessitating quantification of multiple markers. Concerted efforts to identify key markers for hypertension and their quantification, especially using chemical and biosensors, are underway in different parts of the world. Constant evolution of the sensing elements and transduction strategies have contributed to significant improvements in the diagnosis field, especially in the context of sensitivity, response time and selectivity and this when applied to the detection of hypertension markers may prove beneficial. This review summarizes advances in the field of sensor technology towards the detection of biologically relevant entities, arrays and the next generation 'lab-on-a-chip' systems for hypertension.