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Alendronate-functionalized graphene quantum dots (ALEN-GQDs) with a quantum yield of 57% were synthesized via a two-step route: preparation of graphene quantum dots (GQDs) by pyrolysis method using citric acid as the carbon source and post functionalization of GQDs via a hydrothermal method with alendronate sodium. After careful characterization of the obtained ALEN-GQDs, they were successfully employed as sensing materials with superior selectivity and sensitivity for the detection of nanomolar levels of arsenic ions (As(III)). According to the mechanistic investigation, arsenic ions can quench the fluorescence intensity of ALEN-GQDs through metal-ligand interaction between the As(III) ions and the surface functional groups of the fluorescent probe. This probe provided a rapid method to monitor As(III) with a wide detection range (44 nM-1.30 µM) and a low detection limit of 13 nM. Finally, to validate the applicability, this novel fluorescent probe was successfully applied for the quantitative determination of As(III) in rice and water samples.

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Background: Electromagnetic induction hyperthermia is a promising method to treat the deep-seated tumors such as brain and prostatic tumors. This technique is performed using the induction of electromagnetic waves in the ferromagnetic cores implanted at the solid tumor. Objective: This study aims at determining the conditions of the optimal thermal distribution in the different frequencies before performing the in vitro cellular study. Material and Methods: In this experimental study, the i-Cu alloy (70.4-29.6; wt%) was prepared and characterized and then the parameters, affecting the amount of induction heating in the ferromagnetic core, were investigated. Self-regulating cores in 1, 3, 6, and 9 arrangements in the water phantom with a volume of 2 cm3 were used as a replacement for solid tumor. Results: Inductively Coupled Plasma (ICP) analysis and Energy Dispersive X-ray Spectroscopy (EDS) show the uniformity of the alloy after 4 times remeling by vacuum arc remelting furnace. The Vibrating Sample Magnetometer (VSM) shows that the Curie temperature (TC) of the ferromagnetic core is less than 50 °C. Temperature profile with a frequency of 100-400 kHz for 30 min, was extracted by infrared imaging camera, indicating the increase temperature in the range of 42 °C to 46 °C. Conclusion: The optimum conditions with used hyperthermia system are supplied in the frequency of 100 kHz, 200 kHz and 400 kHz with 6, 3 and 1 seeds, respectively. It is also possible to induce a temperature up to 50 °C by increasing the number of seeds at a constant frequency and power, or by increasing the applied frequency at a constant number of seeds.

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Herein, water-soluble emissive carbon quantum dots (His-CQDs) were synthesized from pyrolysis of sodium citrate in the presence of histidine under hydrothermal conditions. The as-synthesized His-CQDs were characterized using Fourier transform infrared (FT-IR), fluorescence spectroscopy, dynamic light scattering (DLS), and transmission electron microscopy (TEM) techniques. The obtained His-CQDs display a strong emission peak at 534 nm when excited at 476 nm with a high quantum yield (61.8 %). The as-synthesized His-CQDs were applied as a new platform for highly selective determination of Mn(II) based on the fluorescence "turn-on" response with a limit of detection of 1.85 µg L-1 (at 3σ) and a linear range of 3.50-35.5 µg L-1 in aqueous solution. The sensing mechanism of the His-CQDs probe for the detection of Mn(II) was studied via density functional theory (DFT), FT-IR, and EDTA complexation methodology. In addition, His-CQDs were successfully applied to determine the accurate amounts of Mn(II) in whole blood control material. More importantly, the integrating such an efficient sensor with point-of-care technology can enable portable, easy-to-use, and rapid sensing systems for better biological and clinical applications.

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Hyperthermia, the mild elevation of temperature to 40-45 °C, can induce cancer cell death and enhance the effects of radiotherapy and chemotherapy. Due to the nature of hyperthermia, especially their ability to combine nanotechnology, hyperthermia possesses the potential to open a novel paradigm for the therapeutic strategies. However, achievement of its full potential as a clinically relevant treatment modality has been restricted by its inability to effectively and preferentially heat malignant cells. The main challenge of current hyperthermia treatment is to adequately heat whole volumes of deep-seated tumors without overheating surrounding healthy tissues. So, hyperthermia is under clinical trials (research study with people) and is not widely available. In this Review, we summarize a basic knowledge of hyperthermia before focusing on their applications to the cancer therapy and synthesis. We try to give a comprehensive view of the role of nanomaterials in the designing of hyperthermia-based therapeutic protocols and compare the studies in this field with the purpose of providing a source of helpful information for planning forthcoming hyperthermia researches. However, establishing comparisons between hyperthermia studies is a challenge due to the widely different conditions used by different authors, which, in some cases, is aggravated by the lack of crucial information concerning a certain aspect of the procedure.

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A voltammetric genosensor has been developed for the early diagnosis of COVID-19 by determination of RNA-dependent RNA polymerase (RdRP) sequence as a specific target of novel coronavirus. The severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) uses an RdRP for the replication of its genome and the transcription of its genes. Here, the silver ions (Ag+) in the hexathia-18-crown-6 (HT18C6) were used for the first time as a redox probe. Then, the HT18C6(Ag) incorporated carbon paste electrode (CPE) was further modified with chitosan and PAMAM dendrimer-coated silicon quantum dots (SiQDs@PAMAM) for immobilization of probe sequences (aminated oligonucleotides). The current intensity of differential pulse voltammetry using the redox probe was found to decrease with increasing the concentration of target sequence. Based on such signal-off trend, the proposed genosensor exhibited a good linear response to SARS-CoV-2 RdRP in the concentration range 1.0 pM-8.0 nM with a regression equation I (µA) = - 6.555 log [RdRP sequence] (pM) + 32.676 (R2 = 0.995) and a limit of detection (LOD) of 0.3 pM. The standard addition method with different spike concentrations of RdRP sequence in human sputum samples showed a good recovery for real sample analysis (> 95%). Therefore, the developed voltammetric genosensor can be used to determine SARS-CoV-2 RdRP sequence in sputum samples. PAMAM-functionalized SiQDs were used as a versatile electrochemical platform for the SARS-CoV-2 RdRP detection based on a signal off sensing strategy. In this study, for the first time, the silver ions (Ag+) in the hexathia-18-crown-6 carrier were applied as an electrochemical probe.

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In this research, we mainly focused on the micro-emulsion synthesis of biotinylated ZnS (zinc sulfide) nanocrystals for avidin recognition. Various samples of Zn(1-x)Mn(x) S, with x = 0.0001, 0.007, 0.02, 0.03, 0.055, 0.09 and 0.13, prepared by quaternary W/O (water-in-oil) microemulsion system. Cyclohexane was used as oil, Triton X-100 as surfactant, n-hexanol as a co-surfactant and mercaptoethanol and thioglycolic acid as linking agents. The obtained products were evaluated by commonly techniques such as: scanning electron microscopy (SEM), transmission electron microscopy (TEM), zeta meter for measurement ZP (zeta potential) and fluorescence spectroscopy analyses. The above-experimental results indicated that the optimum doping concentration of Mn was ~ 5.5% . The fluorescence spectra of the doped crystals consist of orange-red emissions. Eventually, this research showed with increasing more than 18 µl biotin to nanocrystals, no changes were observed in the emission intensity spectra.

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