Intrinsic dual emissive insulin capped Au/Ag nanoclusters as single ratiometric nanoprobe for reversible detection of pH and temperature and cell imaging.

pH and temperature are two important characteristics in cells and the environment. These, not only in the well-done regulation of cell functions but also in diagnosis and treatment, have a key role. Protein-protected bimetallic nanoclusters are abundantly used in the building of biosensors. However, insulin-stabilized Au-Ag nanoclusters with dual intrinsic emission have not been investigated yet. In this work, Dual emissive insulin templated Au-Ag nanocluster (Ins(Au/Ag)NCs) were first synthesized in a simple and green one-put manner. The two emission wavelengths of, as-prepared NCs centered at 410 and 630 nm, excited in one excitation wavelength (330 nm). These two emission peaks were assigned to the di-Tyrosine cross-linked formation and bimetallic nanoclusters respectively. Further analysis displayed that each emission band of Ins(Au/Ag)NCs responded to one variable whilst another peak remained constant; For blue and red emission wavelengths, pH dependency and thermo-responsibility were observed respectively. As-prepared nanoprobe with the intrinsic dual emissive feature was used for ratiometric determination of these parameters, each with a discrete response from another. The linear range of 6.0-9.0 for pH and 1 to 71 °C for temperature was obtained, which comprises the physiological range of pH and temperature and afforded intracellular sensing and imaging capability. As-prepared NCs probe show excellent biocompatibility and cell membrane permeability, and so were successfully applied as direct ratiometric pH and temperature probes in HeLa and HFF cells. More interestingly, this dual emissive nanoprobe is capable of distinguishing cancer cells from normal ones.

Fluorescent folic acid-chitosan/carbon dot for pH-responsive drug delivery and bioimaging.

Nowadays, one of the most important reasons of death in the world is cancer. With the development of nanotechnology, advanced methods for treatment of cancer have introduced. In this work, the fluorescent carbon dots (CDs) were prepared from chitosan as the second abundant polysaccharide present in the nature. The surface of CDs was modified with chitosan (CDs/CS) and then the amino groups of chitosan were conjugated with activated folic acid (CDs/CS-FA) for controlled delivery of doxorubicin (DOX) as anticancer drug against HeLa cancer cells. The DOX loading efficiency of fluorescent CDs/CS-FA was high and nearly 60 %. Due to pH sensitive swelling/deswelling of CS, the percentage of cumulative DOX release could reach 90 % at cancer tissue (pH of 5.0) and 52 % at normal tissue (pH of 7.4) within 30 h. The cytotoxicity study revealed that the synthesized CDs were highly compatible on HeLa cells with cell viability 97-88 %. Cellular imaging shows that the entry of CDs/CS-FA to HeLa cells causes a green fluorescence, while the CDs/CS without FA have a negligible fluorescence. These results are due to the important role of FA in cell internalization. Thus, the CDs/CS-FA nanocarrier is suitable candidate for controlled pH sensitive drug delivery and cellular imaging.

Determination of Atropine by HPLC in Plant of Datura by Liquid-Liquid Extraction and Magnet Solid-Phase Extraction.

Atropine is a tropane alkaloid found in abundance in Datura plant. We used two liquid-liquid extraction methods and magnet solid-phase extraction to compare the amount of atropine in these two types of plants (Datura innoxia and Datura stramonium). The surface magnetic nanoparticle Fe3O4 correction with an amine and dextrin, and finally, magnetic solid-phase extraction Fe3O4@SiO2-NH2-dextrin (MNPs-dextrin), was prepared. We determined the effect of significant parameters in the removal step and optimization of atropine measurements with half-fractional factorial design (25-1) and response surface methodology via central composite design. The optimum conditions are for desorption solvent = 0.5 mL methanol and desorption time of 5 min. We obtained an extraction recovery of 87.63% with a relative standard deviation of 4.73% via six frequented measurements on a 1 µg L-1 atropine standard solution based on the optimum condition. Preconcentration factors for MNPs are 81, limit of detection = 0.76 µg L-1 and limit of quantitation = 2.5 µg L-1.

A novel ratiometric fluorescence probe based on calix[4]arene functionalized polymer dots for bisphenol A detection in real water samples.

Bisphenol A (BPA) is one of key raw materials used in the production of epoxy resins and plastics, which has toxicological effects on humans by disrupting cell functions through a variety of cell signaling pathways. Therefore, it is of great significance to develop a simple, rapid, and accurate BPA detection method in real water samples. In this study, a ratiometric fluorescence method based on yellow-emitting surface-functionalized polymer dots (PFBT@L Pdots) and blue-emitting carbon dots (Cdots) was described for the detection of BPA. Pdots as the detecting part were synthesized by using highly fluorescent hydrophobic Poly[(9,9-dioctylfluorenyl-2,7-diyl)-alt-co-(1,4-benzo-(2,1',3)-thiadiazole)] (PFBT) polymer and (R)-5,11,17,23-Tetra-tert-butyl-25,27-bis[(diphenylphosphinoyl)methoxy]-26-(3-oxabutyloxy)-28-[(1-phenylethyl)- carbamoylmethoxy]calix [4]arene (L) functionalizing ligand, and Cdots as internal reference were prepared by hydrothermal treatment of citric acid and urea. In the presence of BPA, chemical binding of the phosphorus atoms of nearby PFBT@L Pdots with BPA hydroxyl functional groups led to the aggregation of the PFBT@L Pdots aggregation and quenching their yellow emission, but the blue emission of Cdots, on the other hand, remained stable. The proposed PFBT@L Pdots probe was successfully applied for the detection of BPA in real water samples, and the results were in good agreement with those obtained by HPLC-FLD. To the best of our knowledge, this is the first report that the calixarene has been utilized to modify Pdots.

A novel magnetically guided, oxygen propelled CoPt/Au nanosheet motor in conjugation with a multilayer hollow microcapsule for effective drug delivery and light triggered drug release.

In recent years, nanomotors have been developed and attracted extensive attention in biomedical applications. In this work, a magnetically-guided oxygen-propelled CoPt/gold nanosheet motor (NSM) was prepared and used as an active self-propelled platform that can load, transfer and control the release of drug carrier to cancer cells. As a drug carrier, the microcapsules were constructed by the layer-by-layer (LbL) coating of chitosan and carboxymethyl cellulose layers, followed by incorporation of gold and magnetite nanoparticles. Doxorubicin (DOX) as an anti-cancer drug was loaded onto the synthesized microcapsules with a loading efficiency of 77%. The prepared NSMs can deliver the DOX loaded magnetic multilayer microcapsule to the target cancer cell based on the catalytic decomposition of H2O2 solution (1% v/v) via guidance from an external magnetic force. The velocity of NSM was determined to be 25.1 µm s-1 in 1% H2O2. Under near-infrared irradiation, and due to the photothermal effect of the gold nanoparticles, the proposed system was found to rapidly release more drugs compared to that of an internal stimulus diffusion process. Moreover, the investigation of cytotoxicity of NSMs and multilayer microcapsules clearly revealed that they have negligible side effects over all the concentrations tested.

Label-free electrochemical cancer cell detection leveraging hemoglobin-encapsulated silver nanoclusters and Cu-MOF nanohybrids on a graphene-assisted dual-modal probe.

Breast cancer detection at an early stage significantly increases the chances of successful treatment and survival. This study presents an electrochemical biosensor for detecting breast cancer cells, utilizing silver nanoclusters encapsulated by hemoglobin and Cu (II)-porphyrin-metal organic framework (BioMOF) in a graphene-incorporated nanohybrid probe. This Hb-AgNCs@MOF-G probe demonstrates high electrochemical activity, superior dispersity, porosity, and a large surface area for effective functionalization. Using a green ultrasonic-assisted stirring method, we fabricate ultra-small 5 nm particles that readily immobilize on a glassy carbon electrode, generating a detection signal when interacting with ferricyanide/ferrocyanide redox probes. The resulting immunosensor detects as few as 2 cells/mL using Electrochemical Impedance Spectroscopy (EIS) "signal on" and 16 cells/mL via Square Wave Voltammetry (SWV) "signal off", within a broad range of cell concentrations (102-5 × 104 cells/mL). Our designed sensor shows improved selectivity (5- to 16-fold) and robust detection in human blood with a recovery efficiency between 94.8-106% (EIS method) and 95.4-111% (SWV method). This sensor could streamline early cancer diagnosis and monitor patient treatment without requiring labelling or signal amplification. As a pioneering endeavor, we've utilized integrated porous MOFs with Hb-encapsulated silver nanoclusters in cancer detection, where these components collectively enhance the overall functionality.

A paper-based chemical tongue based on the charge transfer complex of ninhydrin with an array of metal-doped carbon dots discriminates natural amino acids and several of their enantiomers.

Simultaneous detection of multiple amino acids (AAs) instead of individual AAs is inherently worthwhile for improving diagnostic accuracy in clinical applications. Here, a facile and reliable colorimetric microfluidic paper-based analytical device (µPAD) using carbon dots doped with transition metals (Cr3+, Mn2+, Fe3+, Co2+, Ni2+, Cu2+, and Zn2+) has been provided to detect and discriminate 20 natural amino acids. To make the colourless metal-doped carbon dots suitable for colorimetric assays, they were mixed with ninhydrin to form a charge transfer complex. This optical tongue system, which was constructed by dropping mixtures of ninhydrin with a series of metal-doped carbon dots on a paper substrate in an array format, represented obvious but different colorimetric signatures for every examined amino acid. Since bovine serum albumin was used as a chiral selector reagent for synthesizing the CDs, the sensor device represented excellent selectivity to identify enantiomeric species of AAs. This is the first optical array device that can simultaneously discriminate AAs and several of their enantiomers. We employed various statistical and chemometric methods to analyze the digital data library collected by Image J software, including principal component analysis (PCA), linear discriminant analysis (LDA), and hierarchical cluster analysis (HCA). Twenty AAs could be well distinguished at various concentrations (10.00, 5.00, 2.50, and 1.25 mM). The colorimetric patterns were highly repeatable and were characteristic of individual AAs. Besides qualitative analysis, the designed µPAD-based optical tongue represented quantitative analysis ability, e.g., for lysine in the concentration ranges of 0.005-20.0 mM with a detection limit of 1.0 × 10-6 M and for arginine in the concentration range of 0.12-20.00 mM with a detection limit of 80.0 × 10-6 M. In addition, the binary, ternary, and quaternary mixtures of AAs could also be well recognized with this sensor.

Fe3 O4 and bimetal-organic framework Zn/Mg composite peroxide-like catalyze luminol chemiluminescence for specific measurement of atropine in Datura plant.

Atropine (AT) is an anticholinergic drug. AT is abundantly in Datura plant seeds. Fe3 O4 @Zn/Mg MOF (Fe3 O4 @MOF) composite was synthesized. The compound had a high peroxidase-like activity in a chemiluminescence (CL) reaction. Addition of AT quenched CL. The linear range and limit of detection were 5-600 µg L-1 and 2 × 10-2 µg L-1 . This method is fast, reversible, and selective, without biodegradability effects, high accuracy, and precision for measuring AT in the Datura plant.

Phototriggered structures: Latest advances in biomedical applications.

Non-invasive control of the drug molecules accessibility is a key issue in improving diagnostic and therapeutic procedures. Some studies have explored the spatiotemporal control by light as a peripheral stimulus. Phototriggered drug delivery systems (PTDDSs) have received interest in the past decade among biological researchers due to their capability the control drug release. To this end, a wide range of phototrigger molecular structures participated in the DDSs to serve additional efficiency and a high-conversion release of active fragments under light irradiation. Up to now, several categories of PTDDSs have been extended to upgrade the performance of controlled delivery of therapeutic agents based on well-known phototrigger molecular structures like o-nitrobenzyl, coumarinyl, anthracenyl, quinolinyl, o-hydroxycinnamate and hydroxyphenacyl, where either of one endows an exclusive feature and distinct mechanistic approach. This review conveys the design, photochemical properties and essential mechanism of the most important phototriggered structures for the release of single and dual (similar or different) active molecules that have the ability to quickly reason of the large variety of dynamic biological phenomena for biomedical applications like photo-regulated drug release, synergistic outcomes, real-time monitoring, and biocompatibility potential.

Silanized fiberglass modified by carbon dots as novel and impressive adsorbent for aqueous heavy metal ion removal.

This work discusses the application of a silanized fiberglass (SFG) modified by carbon dots (CDs) as an effective adsorbent for up-taking some heavy metal ions including lead (Pb2+), chromium (Cr3+), cadmium (Cd2+), cobalt (Co2+), and nickel (Ni2+) as pollutant in the aqueous solution by batch method. Removal tests were carried out after optimization of pH, contact time, initial concentration of metal ions, and CDs amount. The SFG modified with CDs (CDs-SFG) was applied for the removal of 10 ppm of each metal ion solution after 100 min and the corresponding results showed the removal efficiencies of 100, 93.2, 91.8, 90, and 88.3% for Pb2+, Cd2+, Cr3+, Co2+, and Ni2+, respectively. The adsorption capacity of CDs-SFG in the metal ion mixed solution was also evaluated, and the results indicated the same trend in the adsorption capacity for metal ions in the mixed solution, though with lower absolute values compared to the single metal solutions. Moreover, the selectivity of this adsorbent for the adsorption of Pb2+ was almost twice of other tested metal ions. The regeneration of the CDs-SFG showed that its adsorption capacity after five cycles was reduced about 3.9, 6.0, 6.8, 6.7, and 8.0% for Pb2+, Cd2+, Cr3+, Co2+, and Ni2+, respectively. Finally, the applicability of the CDs-SFG adsorbent was examined with the analysis of the metal ions in water and wastewater samples.

A facile and eco-friendly fluorometric method for the determination of methotrexate and folic acid in biological samples based on hollow luminescent carbon dots and chemometrics method.

A rapid, simple, and inexpensive spectrofluorimetric sensor has been developed for the simultaneous determination of methotrexate (MTX) and folic acid (FA) based on their interactions with hollow carbon dots (HCDs). Since the use of folic acid to cope with the toxic side effects of MTX in patients is essential, the simultaneous determination of these two compounds has been interesting. The results showed that  MTX could quench the fluorescence of HCDs with a dynamic quenching mechanism. The sensor exhibited a linear concentration range of 1.0 × 10-6-1.9 × 10-4 mol L-1 for MTX and 1.5 × 10-5-9.4 × 10-4 mol L-1 for FA and the obtained detection limits for MTX and FA were 1.6 × 10-7 and 5.0 × 10-7 mol L-1, respectively. The applicability of the method was investigated in the analysis of the urine samples and the partial least squares (PLS) method was used for the simultaneous determination of MTX and FA.

Design of a novel aptamer/molecularly imprinted polymer hybrid modified Ag-Au@Insulin nanoclusters/Au-gate-based MoS2 nanosheet field-effect transistor for attomolar detection of BRCA1 gene.

Early detection of breast cancer, the first main cause of death in women, with robust assay platforms using appropriate biomarkers is of great importance for diagnosis and follow-up of the disease progression. This paper introduces an extra selective and sensitive label-free aptasensor for the screening of BRCA1 gene biomarker by taking advantage of a gate modified with aptamer and molecularly imprinted polymer hybrid (MIP) as a new synthetic receptor film coupled with an electrolyte-gated molybdenum disulfide (MoS2) field-effect transistor (FET). The Au gate surface of FET was modified with insulin stabilized bimetallic Ag-Au@nanoclusters (Ag-Au@InsNCs), after which, the immobilization of the hybridized aptamer and o-phenylenediamine was electropolymerized to form an aptamer-MIP hybrid receptor. The output characteristics of Apta-MIP hybrid modified Au gate MoS2 FET device were followed as a result of change in electrical double layer capacitance of electrolye-gate interface. The magnitude of decrease in the drain current showed a linear response over a wide concentration range of 10 aM to 1 nM of BRCA1 ssDNA with a sensitivity as high as 0.4851 µA/decade of concentration and a limit of detection (LOD) of 3.0 aM while very low responses observed for non-imprinted polymer. The devised aptasensor not only was capable to the discrimination of the complementary versus one-base mismatch BRCA1 ssDNA sequence, but also it could detect the complementary BRCA1 ssDNA in spiked human serum samples over a wide concentration range of 10 aM to 1.0 nM with a low LOD of 6.4 aM and a high sensitivity 0.3718 µA/decade.

Modification of bimetal Zn/ Mg MOF with nanoparticles Fe3O4 and Fe3O4@SiO2, investigation of the peroxidase-like activity of these compounds by calorimetry and fluorimetry methods.

In this article; the bimetal metal-organic framework Zn/Mg (Zn/Mg MOF) is synthesized. Then Zn/Mg MOF bimetal was combined with Fe3O4 and Fe3O4@SiO2, and composites of Fe3O4@ SiO2/MOF/Dextrin, Fe3O4@SiO2/MOF, Fe3O4@MOF/Dextrin and Fe3O4@MOF made. The peroxidase-like activity of these compounds was investigated and compared by calorimetric Resazurin (Rz) and O-phenylenediamine (OPD); (Rz-H2O2, OPD-H2O2) and fluorimetric Rz and terephtalic acid (TA); (Rz-H2O2, TA-H2O2). The Fe3O4@ MOF/Dextrin composite has the highest peroxidase-like activity. The effect factors (amount of pH (6), the values of TA (1.37 mM), H2O2 (0.025 mM), reaction time (8.15 min), and amount of Composite (116.67 mg)) to increase the catalytic activity of Fe3O4@ MOF/Dextrin measured by chemometrics method. The most suitable linear range of the calibration curve by the TA-H2O2 -Composite fluorimetric method is 1-600 µg L-1, and the detection limit is 2.27 µg L-1. The relative standard deviation (RSD%) for measuring concentration atropine 1 µg L-1 (n = 6) is 1.18%. Finally, from this system for measuring atropine extracted by the Liquid-liquid extraction (LLE) method in two types of plants, D. Innoxia north and west and D. stramonium north and west of Iran (118.25 µg L-1, 79.80 µg L-1) and (18.477 µg L-1, 9.27 µg L-1) used, respectively.

Intercalative binding of two new five-coordinated anticancer Pt(II) complexes to DNA: experimental and computational approaches.

Binding interaction of two organoplatinum complexes, [Pt(C^N)Cl(dppa)], 1, and [Pt(C^N)Cl(dppm)], 2, (C^N = N(1), C(2')-chelated, deprotonated 2-phenylpyridine, dppa = bis(diphenylphosphino)amine, dppm = bis(diphenylphosphino)methane), as anti-tumor agents, with calf thymus DNA (CT-DNA) under pseudo-physiological conditions has been investigated using various biophysical techniques viz., UV-Vis and fluorescence spectroscopies, viscosity measurements, and thermal denaturation experiments. A hypochromic shift in UV-Vis absorption titration, fluorescence enhancement of Pt(II) complexes in the presence of CT-DNA, fluorescence quenching in competitive ethidium bromide displacement assay, and an uptrend in the viscosity (η) and melting temperature (Tm) indicated the existence of a tight intercalative interaction of Pt(II) complexes with CT-DNA. The fluorescence quenching of CT-DNA was a combined quenching of static and dynamic with Stern-Volmer quenching constants of 7.520 × 103 M-1 for complex 1 and 5.183 × 103 M-1 for complex 2, at low concentrations of Pt(II) complexes. Besides the experimental studies, computational studies were done. Molecular modeling studies confirmed the intercalation of the studied complexes by the phenyl groups of dppa and dppm, leading to π-π interactions but with a certain steric hindrance because of the size and shape of the considered complexes. The combination of experimental and computational data showed that reported Pt(II) complexes are promising structures and could be developed for cancer therapeutic applications.Communicated by Ramaswamy H. Sarma.

Role of the Probe Sequence/Structure in Developing an Ultra-Efficient Label-Free COVID-19 Detection Method Based on Competitive Dual-Emission Ratiometric DNA-Templated Silver Nanoclusters as Single Fluorescent Probes.

We report the development of a label-, antibody-, enzyme-, and amplification-free ratiometric fluorescent biosensor for low-cost and rapid (less than 12 min) diagnosis of COVID-19 from isolated RNA samples. The biosensor is designed on the basis of cytosine-modified antisense oligonucleotides specific for either N gene or RdRP gene that can form silver nanoclusters (AgNCs) with both green and red emission on an oligonucleotide via a one-step synthesis process. The presence of the target RNA sequence of SARS-CoV-2 causes a dual-emission ratiometric signal transduction, resulting in a limit of detection of 0.30 to 10.0 nM and appropriate linear ranges with no need for any further amplification, fluorophore, or design with a special DNA fragment. With this strategy, five different ratiometric fluorescent probes are designed, and how the T/C ratio, the length of the stem region, and the number of cytosines in the loop structure and at the 3' end of the cluster-stabilizing template can affect the biosensor sensitivity is investigated. Furthermore, the effect of graphene oxide (GO) on the ratiometric behavior of nanoclusters is demonstrated and the concentration-/time-dependent new competitive mechanism between aggregation-caused quenching (ACQ) and aggregation-induced emission enhancement (AIE) for the developed ssDNA-AgNCs/GO nanohybrids is proposed. Finally, the performance of the designed ratiometric biosensor has been validated using the RNA extract obtained from more than 150 clinical samples, and the results have been confirmed by the FDA-approved reverse transcription-polymerase chain reaction (RT-PCR) diagnostic method. The diagnostic sensitivity and specificity of the best probe is more than >90%, with an area under the receiver operating characteristic (ROC) curve of 0.978.

A one-pot rotational DC-bipolar approach for fabricating artistic metallic carpets.

This is a brief report on the fabrication of concentric multi-element metallic carpets through a one-pot rotational bipolar electro-engineering procedure. A suspended piece of nickel foam as a bipolar electrode (BPE) is rotated in an aqueous solution containing a ternary mixture of metal ions when sufficient DC potential is applied to driving electrodes. The customizable tools of this art are potential gradient, rotation, and concentration/kinetic polarizations. Creating the multi-element radial gradient is typically tested in a one-pot artistic jewelry electroplating.

Trace determination of triazine herbicides in fruit and vegetables using novel hydrophobic deep eutectic solvent-based dispersive liquid-liquid microextraction followed by high-performance liquid chromatography-ultraviolet.

In the present research, a novel hydrophobic deep eutectic solvent-based dispersive liquid-liquid microextraction technique was established and combined with high-performance liquid chromatography-ultraviolet for the determination of triazine herbicides in fruit and vegetable samples. A deep eutectic solvent was synthesized using l-menthol as a hydrogen bond acceptor and ethylene glycol as a hydrogen bond donor and used as a green extractant. The characterization of deep eutectic solvent was investigated by Fourier-transform infrared, nuclear magnetic resonance, and thermogravimetric analysis. Under the optimum conditions, relative standard deviation values for intra-day and inter-day of the method based on seven replicate measurements of 50.0 µg/kg of triazines were in the range of 2.8%-5.5% and 3.7%-7.2%, respectively. The calibration graphs were linear in the range of 3.0-500 µg/kg and the limits of detection were in the range of 1.0-2.0 µg/kg. The relative recoveries of different fruit and vegetable samples that have been spiked with two levels of target compounds were 91.5%-109.8%. The method has good linearity, sensitivity, accuracy, and precision. It is also environmentally friendly and was successfully used to determine the concentrations of triazines in fruit and vegetable samples.

Novel deep eutectic solvent-based liquid phase microextraction for the extraction of estrogenic compounds from environmental samples.

Steroid hormones, such as estrone (E1), 17ß-estradiol (E2), 17ß-ethinylestradiol (EE2) and estriol (E3) are a group of lipophilic active substances, synthesized biologically from cholesterol or chemically. A pH-switchable hydrophobic deep eutectic solvent-based liquid phase microextraction (DES-LPME) technique was established and combined with gas chromatography-mass spectroscopy for the determination of estrogenic compounds in environmental water and wastewater samples. A DES was synthesized using l-menthol as HBA and (1S)-(+)-camphor-10-sulfonic acid (CSA) as HBD, and used as a green extraction solvent. By adjusting the pH of the solution, the unique behavior of the DES in the phase transition and extraction of the desired analytes was investigated. The homogenization process of the mixture is done only by manual shaking in less than 30 seconds and the phase separation is done only by changing the pH and without centrifugation. Some effective parameters on the extraction and derivatization, such as molar ratio of DES components, DES volume, KOH concentration, HCl volume, salt addition, extraction and derivatization time and derivatization prior or after extraction were studied and optimized. Under the optimum conditions, relative standard deviation (RSD) values for intra-day and inter-day of the method based on 7 replicate measurements of 20 ng L-1 of estrogenic compounds and 10 ng L-1 for internal standard in different samples were in the range of 2.2-4.6% and 3.9-5.7%, respectively. The calibration graphs were linear in the range of 0.5-100 ng L-1 and the limits of detection (LODs) were in the range of 0.2-1.0 ng L-1. The relative recoveries of environmental water and wastewater samples which have been spiked with different levels of target compounds were 91.0-108.8%.

Fluorescence sensing and imaging with carbon-based quantum dots for early diagnosis of cancer: A review.

This review discusses recent advances and the reported strategies over the last ten years on the use of carbon-based quantum dots (QDs), including carbon dots (CDs), graphene quantum dots (GQDs), and polymer dots (PDs) in the design of fluorescence imaging and biosensing system for early diagnosis of cancers. Besides, this study comprehensively reports the latest developments in these years in the fluorescence imaging (FI) area with special attention to carbon-based QDs that take advantage of the excellent properties offered by these zero-dimensional (0D) nanomaterials as fluorescent tags. The most remarkable advantages of these carbon nanomaterials in the development of fluorescence sensing and imaging strategies compared to the conventional dyes arise from sharp emission spectra, long photostability, low-cost synthesis, reliability, reproducibility, high fluorescent intensity, and high surface functional groups such as carboxyl and amide, which impart better solubility in many solvents and aqueous media and facilitate their easy functionalization with biological species. The final section discusses the main challenges to be met to take full advantage of these properties in fluorescence bio-sensing and imaging as well as the possible future trends in this field based on the great advances that have occurred in recent years.

Detection and discrimination of antibiotics in food samples using a microfluidic paper-based optical tongue.

Antibiotics are used largely in agriculture and animal farming. As a result, antibiotic residues are found in food products as well as pharmaceutical industries and farming wastes. Since consumption of food products contaminated with antibiotic in excessive residuals causes severe environmental risks, our study here aims to detect the residues level of selected antibiotics in milk and egg. For monitoring of the antibiotic residues in various food diaries, low-cost, simple and rapid methods are required. This paper reports fabricating a disposable microfluidic paper-based analytical device for detection and discrimination of 8 antibiotics. This small but efficient device works based on combination of paper microfluidics, sensor array concept (an array of metallochromic complexes, which provides an optical tongue, and chemometrics data analysis. The discrimination is based on differential interaction of the antibiotics with 5 metal-indicator complexes and displacing the chromogenic indicators. This resulted in specific color changes for each antibiotic. The discriminant models obtained by employing linear discriminant analysis could discriminate antibiotics in real samples of milk and egg white and yolk at concentrations of as low as 5.0 mg L-1 with 100% accuracy. Also, semi-quantitative analysis was provided to detect trace amounts of the antibiotics (1.0 mg L-1).