Biosynthesis of silver nanospheres, kinetic profiling and their application in the optical sensing of mercury and chlorite ions in aqueous solutions.

Pollution of water linked to microbial decontamination and extensive use of sodium chlorite (NaClO2) as a disinfectant, especially in the face of the current COVID-19 situation, is a serious water pollution issue that needs to be addressed. In this context, an environmentally friendly and cost-effective method has been developed for the biomimetic synthesis of Ag nanospheres (Ag NSs) using aqueous extract of Piper nigrum for the detection of chlorite (ClO2-) and mercury (Hg2+) ions. The strong antioxidant properties of the biomolecules present in the Piper nigrum extract reduce silver ions (Ag+) to Ag0. After optimization of the formulation parameters, it was observed that 1 mL of piper nigrum extract was sufficient to reduce and stabilize 100 mL of 1.5 mM of Ag+ in 2.5 h at 30 °C. X-ray diffraction (XRD) pattern of Ag NSs revealed their crystalline nature and the characteristic Bragg's diffraction peaks confirmed their face cubic crystal (FCC) lattice. The characteristic reddish-brown color and absorption surface plasmon resonance (SPR) band at 435 nm confirmed the successful fabrication of Ag NSs. Kinetic analysis revealed a three-phase growth pattern involving nucleation, growth and stabilization. Transmission electron microscopy (TEM) and High-resolution transmission electron microscopy (HRTEM) micrograms, showed spherical NSs with narrow polydispersity with particle size ranging from 10 to 30 nm. The synthesized NSs were exposed to various metal ions and anions. The absorption intensity of Ag NSs quenched in the presence of mercury ions (Hg2+) among the cations and Chlorite ions (ClO2-) among the anions. The limit of detection (LOD) of 7.47 µM and 1.11 µM was evaluated from the calibration curve for Hg2+ and ClO2-, respectively. Based on these promising results, it is suggested that the method reported is a low-cost and one step biogenic protocol for the synthesis of Ag NSs and their employment for the detection of Hg2+ and ClO2-ions.

Evaluation of oxidative stress and antioxidant status: Correlation with the severity of sepsis.

Sepsis is a condition caused by infection followed by unregulated inflammatory response which may lead to the organ dysfunction. During such condition, over-production of oxidants is one of the factors which contribute cellular toxicity and ultimately organ failure and mortality. Antioxidants having free radicals scavenging activity exert protective role in various diseases. This study has been designed to evaluate the levels of oxidative and antioxidative activity in sepsis patients and their correlation with the severity of the sepsis. A total of 100 sepsis patients and 50 healthy controls subjects were enrolled in this study from the period October 2016 to June 2017. The investigation included measurements of oxidative enzyme, myeloperoxidase (MPO), antioxidant enzymes including superoxide dismutase activity (SOD) and catalase activity (CAT) and cytokines (TNF-α, IL-8 and IFN-γ). Furthermore, the level of these activities was correlated with severity of sepsis. Augmented levels of oxidants were found in sepsis as demonstrated by DMPO nitrone adduct formation and plasma MPO level activity (1.37 ± 0.51 in sepsis vs 0.405 ± 0.16 in control subjects). Cytokines were also found to be increased in sepsis patients. However, plasma SOD and CAT activities were significantly attenuated (P < .001) in the sepsis patients compared with controls subjects. Moreover, inverse relation between antioxidant enzymes (SOD and CAT) and organ failure assessment (SOFA), physiological score (APACHE II), organ toxicity specific markers have been observed as demonstrated by Pearson's correlation coefficient. This study suggests that imbalance between oxidant and antioxidant plays key role in the severity of sepsis.

Surfactant Coated Silica Nanoparticles as Smart Scavengers for Adsorptive Removal of Naphthalene.

This manuscript represents the synthesis of silica nanoparticles modified with four different types of cationic surfactants. The surfactant capped nanoparticles have better control over the size of silica nanoparticles. The as formed as model nanomaterials were used for the removal of naphthalene, a simple white crystalline polycyclic aromatic hydrocarbon (PAH) from aqueous media. The obtained materials were characterized by various microscopic and spectroscopic techniques. The average particle size of nanoparticles was approximately between 50 and 75 nm. The removal kinetic and adsorption studies were also conducted on silica nanoparticles with different contact time, initial concentrations of silica and naphthalene to achieve the optimum adsorption conditions. CPB functionalized nanoparticles have displayed higher removal efficiency of more than 85% as compared to 75 to 80% in case of CTAB, CTAC and CPC functionalized silica nanoparticles. The effects of various parameters like pH, adsorbent doses, naphthalene concentration and addition of salt have also been investigated for better understanding of the removal efficacy of prepared nanoparticles.

Metallomicelle templated transition metal nanostructures: synthesis, characterization, DFT study and catalytic activity.

A simple and versatile protocol to achieve surface-modified catalytically efficient nanoparticles employing metallosurfactants as excellent scaffolds has been reported. The metallomicelle act as an efficient single precursor template for metal nanostructure fabrication displaying a strong interrelationship between their size and shape. Preferred binding of nanostructures to a capping agent (amine or carboxylate) alters the activity and dispersibility (aqueous or non-aqueous), resulting in various sizes (sub nm-15 nm) and morphologies (spherical, capsule like). The ligand-nanoparticle surface interaction reveals that acetate binds more effectively to Fe and Zn surfaces while dodecylamine works well for Co, Ni and Cu, corroborated by both DFT and experimental FTIR results. Ab initio studies reveal higher binding energy for Fe which leads to excellent stabilization of particles in the quantum domain, whereas the lower interaction between Zn and the acetate ligand results in much larger sized particles. The nanostructures synthesized possess excellent catalytic activity with the reaction performance following the trend Co > Ni ≈ Cu > Zn > Fe, implying that the conversion rate increases with a decrease in NP size, with the exception of Fe. This study points out a new direction in nanomaterial synthesis establishing correlation between the structure of the metallomicelles and morphology of the metal oxide nanostructures formed.

Luminescent ZnO quantum dots as an efficient sensor for free chlorine detection in water.

Highly luminescent ZnO quantum dots (QDs) synthesized via a simple and facile route are used for the preparation of an optical sensor for the detection of free chlorine. The concentration of free chlorine greatly affects the PL emission of the ZnO QDs at 525 nm. Since hypochlorite gains electrons with high efficiency, it takes electrons from the oxygen vacancies of ZnO QDs, which gives rise to defect emission in ZnO QDs. UV-vis data analysis shows that free chlorine does not affect the optical absorption spectra of ZnO QDs. The optical sensing of free chlorine using ZnO QDs has several advantages, like quick response time, good selectivity and of course high sensitivity. The pH has very little effect on the PL emission of ZnO QDs. It does not interfere in the sensing mechanism for free chlorine. After 60 s, the response of the ZnO QDs remains stable. The present sensor shows high selectivity with respect to various common cations, as well as anions.

Multifaceted approach for the fabrication of metallomicelles and metallic nanoparticles using solvophobic bisdodecylaminepalladium (II) chloride as precursor.

A one-pot synthesis of solvophobic bisdodecylaminepalladium(II) chloride (complex 1) was performed. Complex 1 was characterized using X-ray crystallography and other techniques, namely, mass spectrometry, Fourier transform infrared, NMR, elemental analysis, etc. A multifaceted approach was taken to explore the potential applications of complex 1. The micellization ability of complex 1 was estimated using conductivity method in n-alcohols. The metallomicelles are formed in alcohols, and the process is thermodynamically spontaneous in nature. Using complex 1 as precursor, palladium (Pd) nanoparticles were fabricated using two-phase redox method, where reduction is being performed in core of metallomicelles formed by complex 1 in dichloromethane (DCM). The micellization in DCM is confirmed by small-angle X-ray scattering (SAXS). The SAXS measurements reveal that the micellar of core 4-5 nm is being formed, which further controls the size of nanoparticle. This approach was advantageous in terms of size control, methodology, and yield. Pd nanoparticles were characterized using transmission electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, and UV-visible spectroscopy and were also screened for bovine serum albumin interactions. Complex 1 and Pd nanoparticles were found to possess antimicrobial property with broad spectrum and are active against bacteria and fungi. The cytotoxicity analyses were performed over healthy cells (Vero cell lines extracted from kidney of green monkey), and the results reveal IC50 value of 10 µg/mL for complex 1.

Varicella-zoster DNA in saliva of patients with meningoencephalitis: a preliminary study.

OBJECTIVES: Since the routine use of polymerase chain reaction testing (PCR) in diagnosing herpes infections, varicella-zoster virus is increasingly recognized as a cause of varicella-zoster meningoencephalitis (VZV ME) among immunocompetent patients. We were interested to determine whether patients with VZV ME had VZV DNA in their saliva during the acute phase of the illness. MATERIALS AND METHODS: Forty-five consecutive patients who underwent a lumbar puncture for diagnostic purposes were included in the study. The cerebrospinal fluid was examined for the presence of VZV DNA by PCR, and patients with positive findings were treated with acyclovir. The saliva was later analyzed in a blinded fashion for the presence of VZV DNA. RESULTS: VZV DNA was found in saliva in four of five (80%) patients with PCR confirmed VZV ME (sensitivity 0.8, specificity 0.84, and likelihood ratio 5). This was significantly more than in patients with non-zoster viral ME (0%, P = 0.009), parainfectious headache (12%, P = 0.03) and controls (9.5%, P = 0.007). In immunocompromised patients with systemic lymphoma and AIDS, VZV DNA was present at a similar rate (67%, P = 0.6). CONCLUSIONS: We have found VZV DNA in saliva of patients with PCR confirmed VZV ME at a higher proportion than in controls and patients with non-VZV viral ME. This finding might be of clinical importance, especially in immunocompetent individuals with suspected VZV ME where the results of genetic and immunological testing are not conclusive.

Tyloxapol niosomes as prospective drug delivery module for antiretroviral drug nevirapine.

With the aim of assuring more patient compliant pharmacotherapy for acquired immuno deficiency syndrome, a formulation of the first line anti-retroviral drug, nevirapine (NVP), has been developed by encapsulating it within niosomes. Biocompatible niosomes were fabricated using a biological surfactant, tyloxapol, with variable cholesterol concentrations. Formulation with surfactant/cholesterol molar ratio 1:0.1 exhibits maximum stability and optimum hydrophobicity. Thus, it is most suitable for the entrapment of NVP and has high entrapment efficiency of 94.3%. FTIR and DSC results indicate that NVP has sufficient compatibility with the excipients of the formulation. Photoluminescence quenching measurements were employed to elucidate the position of drug molecules in niosome bilayer along with the partition coefficient. Dissolution results indicate that the efflux of drug is sustained which creates a depot effect and decreases the fluctuations in drug release. Such a versatile and improved formulation of NVP is expected to increase its therapeutic index and alleviate toxic systemic side effects while improving the quality of life and duration of survival of the patients.

Multiple latent viruses reactivate in astronauts during Space Shuttle missions.

Latent virus reactivation and diurnal salivary cortisol and dehydroepiandrosterone were measured prospectively in 17 astronauts (16 male and 1 female) before, during, and after short-duration (12-16 days) Space Shuttle missions. Blood, urine, and saliva samples were collected during each of these phases. Antiviral antibodies and viral load (DNA) were measured for Epstein-Barr virus (EBV), varicella-zoster virus (VZV), and cytomegalovirus (CMV). Three astronauts did not shed any virus in any of their samples collected before, during, or after flight. EBV was shed in the saliva in all of the remaining 14 astronauts during all 3 phases of flight. Seven of the 14 EBV-shedding subjects also shed VZV during and after the flight in their saliva samples, and 8 of 14 EBV-shedders also shed CMV in their urine samples before, during, and after flight. In 6 of 14 crewmembers, all 3 target viruses were shed during one or more flight phases. Both EBV and VZV DNA copies were elevated during the flight phase relative to preflight or post-flight levels. EBV DNA in peripheral blood was increased preflight relative to post-flight. Eighteen healthy controls were also included in the study. Approximately 2-5% of controls shed EBV while none shed VZV or CMV. Salivary cortisol measured preflight and during flight were elevated relative to post-flight. In contrast DHEA decreased during the flight phase relative to both preflight and post-flight. As a consequence, the molar ratio of the area under the diurnal curve of cortisol to DHEA with respect to ground (AUCg) increased significantly during flight. This ratio was unrelated to viral shedding. In summary, three herpes viruses can reactivate individually or in combination during spaceflight.

Selenium nanomaterials: applications in electronics, catalysis and sensors.

This review provides insights into the synthesis, functionalization, and applications of selenium nanoparticles in electronics, optics, catalysis and sensors. The variation of physicochemical properties such as particle size, surface area, and shape of the selenium nanoparticles and the effect of experimental conditions has also been discussed. An overview has also been provided on the fundamental electrical and optical properties of selenium nanomaterials as well as their utilization in different research fields. The work presents an insight on selenium nanoparticles with interesting properties and their future applications.

Surfactant anchoring and aggregate structure at silica nanoparticles: a persuasive facade for the adsorption of azo dye.

Nanotechnology's aptitude to silhouette matter at the scale of the nanometer has unlocked the flap to new inventions of applications in material science and nanomedicine. Engineered silica nanoparticles are key actor of this strategy. The amphitheatre of silica nanoparticles is inexplicably bilateral. Silica particles play essential function in everyday commercial purposes for instance energy storage, chemical and biological sensors, food processing and catalysis. One of the most appealing applications to emerge in the recent years is the use of silica particles for cleaning up contaminants in groundwater, soil and sediments. Herein this work, surfactant modified silica nanoparticles with unique surface and pore properties as well as high surface areas have been extensively investigated as an alternative for the dye removal. The physical and chemical characterizations of adsorbent have been studied using FTIR and scanning electron microscopy. The present investigation aims to explore the comparative effect of different surfactants during the formation of the target composite materials. The effects of various parameters like pH, adsorbent doses, dye concentration, addition of salt have also been investigated. These findings indicate that the nano silica particles are effective materials for dye removal and can be used to alleviate environmental problems.

Gamma-Fe2O3 nanospindles for environmental remediation: a study on the adsorption and desorption characteristics of acridine orange and direct red dyes.

In this paper, the adsorption and desorption characteristics of two harmful dyes, i.e., acridine orange (AO; cationic dye) and direct red 81 (DR; anionic dye) from aqueous solutions onto gamma-Fe2O3 nanospindles have been investigated. The nanospindles were synthesized by facile chemical precipitation method and characterized in detail in terms of their morphological, compositional and optical properties. Batch mode experiments were conducted to examine the adsorption process by investigating several factors such as effect of pH, amount of adsorbent dose, and effect of dye concentrations. The experimental results indicated that the maximum adsorption capacity occurred at pH = 6.0 for AO and at pH = 4.0 for DR, respectively with 0.03 gm of adsorbent. Langmuir, Freundlich, Temkin, and Dubinin-Radushkevich isotherm models have been used to evaluate the ongoing adsorption. Kinetic parameters for the adsorption have also been applied. Moreover, the gamma-Fe2O3 nanospindles and the adsorbed dyes were desorbed with good performance and could be reused to absorb the dyes again.

Removal of water contaminants by iron oxide nanomaterials.

In recent years, there has been increasing concern about the usage of a broad range of organic substances, heavy metals and aromatic compounds in the aquatic environment due to their wide distribution and potential adverse health effects. The presence of toxic contaminants in water effluent, even at very low concentrations, is extremely harmful and undesirable. Various treatment processes have been investigated to reduce these toxic pollutants from wastewater. Because of the chemical stability of the contaminants, these technologies have proved to be ineffective for handling waste effluents. Nanotechnology offers the possibility of efficient removal of pollutants as nanoparticles have a smaller size and higher adsorptive surface area. From the past few years, nanoscale iron oxides such as magnetite, maghemite, and hematite have been used for the separation and removal of organic and inorganic contaminants. In this review we summarize the use of iron oxide nanomaterials performed over the last few years for the removal of dyes, heavy metals and aromatic compounds.

Au nanoparticles decorated graphitic carbon nitride nanosheets as a sensitive and selective fluorescence probe for Fe3+ and dichromate ions in aqueous medium.

Graphitic carbon nitride mutated with metal nanoparticles has captivated great interest as an effective fluorescent sensor for the detection of harmful ions present in water. In the present work, bulk-gCN was synthesized using melamine as precursor, and further Au-gCN nanocomposite were fabricated via in-situ direct reduction deposition method. The structural, morphological, compositional, stability and optical properties of bulk gCN and Au-gCN nanocomposite were examined using various scattering and spectroscopic techniques such as HRTEM, XPS, XRD and SEM. The synthesized bulk gCN straggles during selectivity studies with different cations and anions because of its uneven surface morphology, however in Au-gCN gold nanoparticles are uniformly distributed on the gCN sheets which results in its enhanced selectivity over bulk gCN. This leads to the fabrication of an optical sensor for Fe3+ and Cr2 ions with limit of detection of 4.62 and 2.77 µM, respectively. The sensing of Fe3+ ions corresponds to the photoinduced electron transfer (PET) mechanism, while the detection of chromate species is associated with an inner filter effect (IFE). The practical applicability of the sensor was also evaluated for different environmental water samples. The high stability, sensitivity, and specificity of Au-gCN nanocomposite make it a potential fluorescent probe for Fe3+ and Cr2 ions in water samples.

Preserving plum perfection: Buckwheat starch edible coating with xanthan gum and lemongrass essential oil.

The research focused on the fabrication of composite coatings using buckwheat starch (BS) and xanthan gum (XG) with incorporation of lemongrass (Cymbopogon citratus) essential oil (LEO) with varying concentration (0.75 %, 1.0 % and 1.25 % (w/v). BS was extracted from buckwheat groats (Fagopyrum esculentum) and its physico-chemical characteristics were determined. BS showed spherical and polygonal morphology and its XRD pattern was similar to starch extracted from other cereal sources. The amount of reducing sugar, starch and amylose content in extracted BS were 0.99 ± 0.33 %, 86.32 ± 0.22 % and 21.02 ± 1.89 % respectively, which indicates that BS is a suitable base material for the formation of edible coatings. XG was mixed with BS in different ratios (1:1, 2:1, 3:1 and 4:1) to optimize the best ratio of combination for composite coatings. The coating with a ratio of 2:1 was very smooth and was chosen for incorporation of LEO and the coatings physical, functional, mechanical, thermal and micro-structural characteristics were examined. The coating S5 with 1.25 % (w/v) concentration of LEO showed the best results with least moisture content (MC), minimum water vapor permeability (WVP) and maximum contact angle value. Moreover, the S5 formulation had the highest antioxidant (73.3 %) ability and maximum antimicrobial efficiency with inhibition zones of 22.09 ± 0.06 mm and 28.65 ± 0.14 mm against S. aureus and E. coli respectively. The coatings were then coated on plum fruit, and various parameters like weight loss, pH, shrinkage and TSS were calculated every 4th day during the 20 days of refrigeration period. The coated plums' ripening pace was delayed by the S5 formulation which improved moisture retention, maintained the plums' TSS value and overall pH. Therefore, composite coatings made up of BS, XG and 1.25 % (w/v) can be used as a cost-effective bio-active coating material for plum preservation under refrigeration conditions.

Reactivation of latent viruses is associated with increased plasma cytokines in astronauts.

Success of long duration space missions will depend upon robust immunity. Decreased immunity has been observed in astronauts during short duration missions, as evident by the reactivation of latent herpes viruses. Seventeen astronauts were studied for reactivation and shedding of latent herpes viruses before, during, and after 9-14 days of 8 spaceflights. Blood, urine, and saliva samples were collected 10 days before the flight (L-10), during the flight (saliva only), 2-3h after landing (R+0), 3 days after landing (R+3), and 120 days after landing (R+120). Values at R+120 were used as baseline levels. No shedding of viruses occurred before flight, but 9 of the 17 (designated "virus shedders") shed at least one or more viruses during and after flight. The remaining 8 astronauts did not shed any of the 3 target viruses (non-virus shedders). Virus-shedders showed elevations in 10 plasma cytokines (IL-1α, IL-6, IL-8, IFNγ, IL-4, IL-10, IL-12, IL-13, eotaxin, and IP-10) at R+0 over baseline values. Only IL-4 and IP-10 were elevated in plasma of non-virus shedders. In virus shedders, plasma IL-4 (a Th2 cytokine) was elevated 21-fold at R+0, whereas IFNγ (a Th1 cytokine) was elevated only 2-fold indicating a Th2 shift. The inflammatory cytokine IL-6 was elevated 33-fold at R+0. In non-shedding astronauts at R+0, only IL-4 and IP-10 levels were elevated over baseline values. Elevated cytokines began returning to normal by R+3, and by R+120 all except IL-4 had returned to baseline values. These data show an association between elevated plasma cytokines and increased viral reactivation in astronauts.

Nitric oxide (NO) counteracts cadmium induced cytotoxic processes mediated by reactive oxygen species (ROS) in Brassica juncea: cross-talk between ROS, NO and antioxidant responses.

Research on NO in plants has achieved huge attention in recent years mainly due to its function in plant growth and development under biotic and abiotic stresses. In the present study, we investigated Cd induced NO generation and its relationship to ROS and antioxidant regulation in Brassica juncea. Cd accumulated rapidly in roots and caused oxidative stress as indicated by increased level of lipid peroxidation and H2O2 thus, inhibiting the overall plant growth. It significantly decreased the root length, leaf water content and photosynthetic pigments. A rapid induction in intracellular NO was observed at initial exposures and low concentrations of Cd. A 2.74-fold increase in intracellular NO was recorded in roots treated with 25 µM Cd than control. NO effects on Malondialdehyde (MDA) content and on antioxidant system was investigated by using sodium nitroprusside (SNP), a NO donor and a scavenger, [2-(4-carboxy-2-phenyl)-4,4,5,5-tetramethylinidazoline-1-oxyl-3-oxide] (cPTIO). Roots pretreated with 5 mM SNP for 6 h when exposed to 25 µM Cd for 24 h reduced the level of proline, non-protein thiols, SOD, APX and CAT in comparison to only Cd treatments. However, this effect was almost blocked by 100 µM cPTIO pretreatment to roots for 1 h. This ameliorating effect of NO was specific because cPTIO completely reversed the effect in the presence of Cd. Thus, the present study report that NO strongly counteracts Cd induced ROS mediated cytotoxicity in B. juncea by controlling antioxidant metabolism as the related studies are not well reported in this species.

Adsorption studies of cationic, anionic and azo-dyes via monodispersed Fe3O4 nanoparticles.

The present paper reports the applicability of magnetite (Fe3O4) nanoparticles as an adsorbent for the removal of three dyes viz. Acridine orange (cationic dye), Comassie Brilliant Blue R-250 (anionic dye) and Congo red (azo dye) from their aqueous solution. The Fe3O4 nanoparticles were synthesized via simple chemical precipitation method using CTAB, as surfactant. The as-prepared nanoparticles were characterized in terms of their morphological, structural and optical properties by using transmission electron microscopy X-ray diffraction and UV-visible spectroscopic measurements. The dye removal efficiency of Fe3O4 NPs have been determined by investigating several factors such as effect of pH, amount of adsorbent dose and effect of contact time on different dye concentrations. Langmuir and Freundlich adsorption isotherms have also been studied to explain the interaction of dyes. The experimental data indicate that the adsorption rate follows pseudo- second-order kinetics for the removal of all the three dyes. Moreover, the nanoparticles and the adsorbed dyes were desorbed. The identities of recovered nanoparticles as well as the three dyes have been found, as same and were reused.

An Overview of Security Materials in Banknotes and Analytical Techniques in Detecting Counterfeits.

Counterfeiting or forged imitation of banknotes is a perpetual practice engulfing global economies. This not only poses challenges for the material scientists to come forth with advanced security materials but also demands veracious forensic examination to detect counterfeits. The present article pursues novel efforts in summarizing a study that lays focus on the recent optical and analytical examinations being used for the characterization and detection of chemical profiles of authentic and counterfeited banknotes. The article briefs the trends in banknote materials, security paper manufacturing process, security inks used for printing, and types of the security printing process in banknote practices. Reported literature shows the introduction of new anti-counterfeiting materials viz. magnetically-responsive photonic anti-counterfeiting watermarks, and fluorescent nanoparticles that can be used as anti-counterfeiting inks, anti-stokes inks, metameric inks, etc. Analytical techniques such as IR spectroscopy, Raman spectroscopy, Mossbauer spectroscopy, X-ray diffraction, X-ray fluorescence, LIBS, XRF, ELDI-MS, EASI/DESI-MS, HPLC, VSC, AFM, etc. in conjunction with different chemometrics approaches have been critically discussed. The study also presents the future scope in banknote examination like the use of hyper spectral imaging and sensor-based counterfeit detection systems.

Effect of Synthesis Methods and Conditions on Properties and Applications of Carbon Dots for the Detection of Potential Water Contaminants: A Review.

The worldwide pollution of water bodies by potential contaminants such as heavy metals, dyes, and pesticides etc. have severely affected the entire eco-system due to their toxic mobility and tough degradation in water. Consequently, there is a requirement to develop cost-competitive and easily handleable sensing materials which can detect targets sensitively and with selectivity. Among the low-cost sensory materials, carbon dots (CDs) constitute an important class of carbon nanomaterial with unique photostability, electronic and fluorescent properties. This review is an effort to comprehend the recent improvements in the sensing applications of CDs with prominence on synthetic routes, the effect of various synthesis parameters on physical properties (quantum yield, size range), detection mechanisms, and detection parameters (limit of detection, interference etc.). Particularly, the scope and progress for the detection of potential water contaminants using CDs have been explored and a holistic view of mechanisms of their detection has been included.

Holistic view of mechanisms for different types of signals generated by CDs.