A review on the chemical and biological sensing applications of silver/carbon dots nanocomposites with their interaction mechanisms.

The development of new nanocomposites has a significant impact on modern instrumentation and analytical methods for chemical analysis. Due to their unique properties, carbon dots (CDs) and silver nanoparticles (AgNPs), distinguished by their unique physical, electrochemical, and optical properties, have captivated significant attention. Thus, combining AgNPs and CDs may produce Ag/CDs nanocomposites with improved performances than the individual material. This comprehensive review offers an in-depth exploration of the synthesis, formation mechanism, properties, and the recent surge in chemical and biological sensing applications of Ag/CDs with their sensing mechanisms. Detailed insights into synthesis methods to produce Ag/CDs are unveiled, followed by information on their physicochemical and optical properties. The crux of this review lies in its spotlight on the diverse landscape of chemical and biological sensing applications of Ag/CDs, with a particular focus on fluorescence, electrochemical, colorimetric, surface-enhanced Raman spectroscopy, and surface plasmon resonance sensing techniques. The elucidation of sensing mechanisms of the nanocomposites with various target analytes adds depth to the discussion. Finally, this review culminates with a concise summary and a glimpse into future perspectives of Ag/CDs aiming to achieve highly efficient and enduring Ag/CDs for various applications.

Hagenia abyssinica-Biomediated Synthesis of a Magnetic Fe3O4/NiO Nanoadsorbent for Adsorption of Lead from Wastewater.

Magnetic nanocomposite adsorbents are cost-effective, environmentally friendly, easy to use, and highly efficient at removing metals from large volumes of wastewater in a short time by using an external magnetic field. In this study, an Fe3O4/NiO composite nanoadsorbent was prepared by varying the mass percent ratios of NiO (50, 40, 30, 20%), which are denoted Fe3O4/50%NiO, Fe3O4/40%NiO, Fe3O4/30%NiO, and Fe3O4/20%NiO, respectively, using Hagenia abyssinica plant extract as the template/capping agent and a simple mechanical grinding technique. The nanocomposites were characterized using an X-ray diffractometer (XRD), scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) spectroscopy, nitrogen adsorption, and ζ-potential measurements. The adsorption performance of the nanoadsorbent was assessed for the removal of lead (Pb2+) ions from aqueous solutions. Among the composite adsorbents, Fe3O4/50%NiO demonstrated the best Pb(II) removal efficiency (96.65%) from aqueous solutions within 80 min at pH 8, at a 100 mg/L lead concentration and 0.09 g of adsorbent dose. However, with the same parameter, only 62.8% of Pb(II) was removed using Fe3O4 nanoparticles (NPs). The adsorptive performance indicated that the optimum amount of porous material (NiO) in the preparation of the Fe3O4/NiO composite nanoadsorbent, with the aid of H. abyssinica plant extract, enhances the removal of toxic heavy metals from aqueous solutions. Multiple isotherm and kinetic models were used to analyze the equilibrium data. Adsorption isotherm and kinetic studies were found to follow the Freundlich isotherm and pseudo-second-order kinetics, respectively.

Adsorptive removal of heavy metals from wastewater using Cobalt-diphenylamine (Co-DPA) complex.

Heavy metals like Cadmium, Lead, and Chromium are the pollutants emitted into the environment through industrial development. In this work, a new diphenylamine coordinated cobalt complex (Co-DPA) has been synthesized and tested for its efficiency in removing heavy metals from wastewater, and its adsorption capacity was investigated. The effectiveness of heavy metals removal by Co-DPA was evaluated by adjusting the adsorption parameters, such as adsorbent dose, pH, initial metals concentration, and adsorption period. Heavy metal concentrations in real sample were 0.267, 0.075, and 0.125 mg/L for Cd2+, Pb2+, and Cr3+ before using as-synthesized Co-DPA to treat wastewater. After being treated with synthesized Co-DPA the concentration of heavy metals was reduced to 0.0129, 0.00028, 0.00054 mg/L for Cd2+, Pb2+, and Cr3+, respectively, in 80 min. The removal efficiency was 95.6%, 99.5%, and 99.5% for the respective metals. The adsorption process fitted satisfactorily with Freundlich isotherm with R2(0.999, 0.997, 0.995) for Cd2+, Pb2+, and Cr3+, respectively. The kinetic data obeyed the pseudo-second order for Cd2+ and Cr2+ and the pseudo-first order for Pb2+. Based on the results obtained within the framework of this study, it is concluded that the as-synthesized Co-DPA is a good adsorbent to eliminate heavy metal ions like Cd2+, Pb2+, and Cr3+from wastewater solution. In general, Co-DPA is a promising new material for the removal of heavy metal ions from water.

Highly efficient visible light active ZnO/Cu-DPA composite photocatalysts for the treatment of wastewater contaminated with organic dye.

Industrial effluents are a leading major threat for water contamination, subsequently which results in severe health associated risks. Hence, purifying wastewater before releasing into the water resources is essential to avoid contamination. In this study, ZnO/Cu-DPA nano-composites were prepared by altering the percentage of Cu-DPA (20%, 30%, 40%, and 50% which are denoted to be ZnO/20%Cu-DPA, ZnO/30%Cu-DPA, ZnO/40%Cu-DPA and ZnO/50%Cu-DPA) using a simple mechanical grinding process. Several spectroscopic studies were employed such as electron paramagnetic analysis (EPR), powdered X-ray diffractometer (PXRD), UV-Vis absorbance spectroscopy, Fourier transform infrared (FT-IR) spectroscopy and scanning electron microscope to characterize these nano-composites. The photo-catalytic activities of the prepared nano-composites were studied by degrading MB under visible light irradiation. ZnO, ZnO/20%Cu-DPA, ZnO/30%Cu-DPA, ZnO/40%Cu-DPA and ZnO/50%Cu-DPA degradation efficiencies were determined to be 71.8, 78.5, 77.1, and 66.1%, respectively. Among the composite catalysts, the ZnO/20%Cu-DPA coupled system are demonstrated the best efficiency (87%) for photo-degradation of MB within 80 min when exposed to visible light. The ZnO/Cu-DPA nano-composites had a greater MB photodegradation efficiency than pristine ZnO owing to p-n heterojunction in the linked system. Under visible light irradiation, the ZnO/20%Cu-DPA catalysed the conversion of dissolved O2 to hydroxyl radicals (OH·), triggering the reduction of MB. This suggests that ·OH is the primary specific active radical involved in the photo-catalytic decomposition of MB. Furthermore, EPR analysis indicates the existence of ·OH in the photo-catalytic system. The proposed nano-composites (ZnO/20%Cu-DPA) reusability was investigated across three cycles as the most efficient photo-catalyst. The results show that, the ZnO/Cu-DPA nano-catalyst is a potential candidate for the remediation of dirty water.

Polyvinylpyrrolidone-passivated fluorescent iron oxide quantum dots for turn-off detection of tetracycline in biological fluids.

Tetracycline is an antibiotic that has been prescribed for COVID-19 treatment, raising concerns about antibiotic resistance after long-term use. This study reported fluorescent polyvinylpyrrolidone-passivated iron oxide quantum dots (IO QDs) for detecting tetracycline in biological fluids for the first time. The as-prepared IO QDs have an average size of 2.84 nm and exist a good stability under different conditions. The IO QDs' tetracycline detection performance could be attributed to a combination of static quenching and inner filter effect. The IO QDs displayed high sensitivity and selectivity toward tetracycline and achieved a good linear relationship with the corresponding detection limit being 91.6 nM.

Dodonaea angustifolia Extract-Assisted Green Synthesis of the Cu2O/Al2O3 Nanocomposite for Adsorption of Cd(II) from Water.

The enhanced worldwide concern for the protection and safety of the environment has made the scientific community focus their devotion on novel and highly effective approaches to heavy metals such as cadmium (Cd) pollutant removal. In this research, Dodonaea angustifolia plant extract-mediated Al2O3 and Cu2O nanoparticle (NP) syntheses were accomplished using the coprecipitation method, and the Cu2O/Al2O3 nanocomposite was prepared by simple mixing of Cu2O and Al2O3 NPs for the removal of Cd(II) ions from aqueous solution. Therefore, an efficient green, economical, facile, and eco-friendly synthesis method was employed, which improved the aggregation of individual metal oxide NPs. The chemical and physical properties of the nanocomposite were examined by different characterization techniques, including scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and Brunauer-Emmett-Teller (BET) surface area analysis. Furthermore, the performances of the nanoadsorbents for the adsorptive eradication of Cd2+ ions from water were investigated. The influence of pH, contact time, initial Cd quantity, and nanocomposite amount on adsorption effectiveness was carefully studied. The adsorption rates of the Cu2O/Al2O3 nanocomposite were rapid, and adsorption equilibrium was attained within 60 min for 97.36% removal of Cd(II) from water. The adsorption isotherm data were best fitted by the pseudo-second-order kinetic and Langmuir isotherm models with the highest adsorption ability of 4.48 mg/g. Therefore, the synthesized Cu2O/Al2O3 nanocomposite could be a potential candidate for a highly efficient adsorbent for heavy metal ion removal from aqueous solutions.

Green synthesis of multi-functional carbon dots from medicinal plant leaves for antimicrobial, antioxidant, and bioimaging applications.

In this research work, carbon dots (CDs) were synthesized from the renewable leaves of an indigenous medicinal plant by the one-pot sand bath method, Azadirachta indica. The synthesized CDs were characterized for its optical properties using UV-Vis, Fluorescence and Fourier transform infrared (FT-IR) spectrophotometry and for structural properties using dynamic light scattering (DLS), X-ray Diffraction (XRD) and high resolution Transmission electron microscopy (HR-TEM). The synthesized CDs exhibited concentration dependent biocompatibility when tested in mouse fibroblast L929 cell line. The EC50 values of biomedical studies, free radical scavenging activity (13.87 µgmL-1), and total antioxidant capacity (38 µgmL-1) proved CDs were exceptionally good. These CDs showed an appreciable zone of inhibition when examined on four bacterial (two gram-positive and gram-negative) and two fungal strains at minimum concentrations. Cellular internalisation studies performed on human breast cancer cells (MCF 7- bioimaging) revealed the applicability of CDs in bioimaging, wherein the inherent fluorescence of CDs were utilised. Thus, the CDs developed are potential as bioimaging, antioxidants and antimicrobial agents.

Status Quo on Graphene Electrode Catalysts for Improved Oxygen Reduction and Evolution Reactions in Li-Air Batteries.

Reduced global warming is the goal of carbon neutrality. Therefore, batteries are considered to be the best alternatives to current fossil fuels and an icon of the emerging energy industry. Voltaic cells are one of the power sources more frequently employed than photovoltaic cells in vehicles, consumer electronics, energy storage systems, and medical equipment. The most adaptable voltaic cells are lithium-ion batteries, which have the potential to meet the eagerly anticipated demands of the power sector. Working to increase their power generating and storage capability is therefore a challenging area of scientific focus. Apart from typical Li-ion batteries, Li-Air (Li-O2) batteries are expected to produce high theoretical power densities (3505 W h kg-1), which are ten times greater than that of Li-ion batteries (387 W h kg-1). On the other hand, there are many challenges to reaching their maximum power capacity. Due to the oxygen reduction reaction (ORR) and oxygen evolution reaction (OES), the cathode usually faces many problems. Designing robust structured catalytic electrode materials and optimizing the electrolytes to improve their ability is highly challenging. Graphene is a 2D material with a stable hexagonal carbon network with high surface area, electrical, thermal conductivity, and flexibility with excellent chemical stability that could be a robust electrode material for Li-O2 batteries. In this review, we covered graphene-based Li-O2 batteries along with their existing problems and updated advantages, with conclusions and future perspectives.

Novel synthesis of fluorescent carbon dots from bio-based Carica Papaya Leaves: Optical and structural properties with antioxidant and anti-inflammatory activities.

Fluorescent carbon dots (CDs) are prepared from a natural resource Carica Papaya Leaves, by sand bath method. The as-synthesized CDs optical and structural properties were characterized by UltraViolet-Visible, FT- IR, and fluorescence spectroscopy. Also the size, shape, and particle size distribution was studied using Transmission electron microscopy technique. These CDs were examined for biomedical applications like free radical scavenging activity using DPPH assay, antioxidant activity using phosphomolybdate assay, and in vitro anti-inflammatory activity using membrane stabilization protocol. The CDs exhibited excellent biological activities at lower concentrations and showed notable half-maximal effective concentration (EC50). The EC50 of free radical scavenging activity (27.6 µg/mL), antioxidant activity (23.00 µg/mL), and in vitro anti-inflammatory activity (15.52 µg/mL) signifies that CDs can be potential therapeutic agents.

Sand bath assisted green synthesis of carbon dots from citrus fruit peels for free radical scavenging and cell imaging.

A sand bath assisted strategy for the synthesis of fluorescent carbon dots (CDs) using citrus fruit peels as a renewable green resource is reported in this work. The CDs were synthesized without any alkaline or acidic environment. The synthesized CDs were characterized by various spectroscopic and microscopy techniques. The CDs exhibited excellent water solubility and superior optical properties like excitation dependent emission, and multicolor fluorescence. In addition, the CDs have exhibited remarkable free radical scavenging activity (EC50: 4.7382 µg ml-1).The CDs were highly biocompatible and showed lower toxicity. The CDs when modified with folic acid have shown a significant potential as biological labels for cellular imaging at multiple excitations. Synthesis of CDs from natural fruit peels as an excellent carbon source for versatile applications has been demonstrated.

Manganese-doped green tea-derived carbon quantum dots as a targeted dual imaging and photodynamic therapy platform.

In this work, manganese-doped carbon quantum dots (Mn-CQDs) have been synthesized through a one-pot hydrothermal method by using waste green tea. The Mn2+ dopants were introduced to impart magnetic resonance capability. Upon optimization of the experimental conditions, magnetofluorescent Mn-CQDs exhibit an excitation-dependent blue emission. The abundant functional groups on Mn-CQDs not only promote water solubility but also allow straightforward functionalization with amine groups. The amine-terminated Mn-CQDs were then subsequently conjugated to folic acid (FA) and chlorin e6 (Ce6) to obtain the Mn-CQDs@FA/Ce6 magnetofluorescent photodynamic therapy (PDT) agent. in vitro studies using three different cells indicated specific targeting of Mn-CQDs@FA/Ce6 to the overexpressing folate receptor human epithelial carcinoma cell line (HeLa) cancer cells. Furthermore, Mn-CQDs@FA/Ce6 enhanced magnetic resonance imaging (MRI) signal with an r2 /r1 ratio of 5.77. Favorably, by using the Mn-CQDs@FA delivery system, active Ce6 can reach the cellular interior while its red fluorescence (FL) and reactive oxygen species generation can be retained, as has been verified by confocal microscopy. in vitro cell viability studies verified the biocompatibility of Mn-CQDs@FA/Ce6 nanohybrid with no significant toxicity up to 500 ppm while PDT treatment with 5 min irradiation (671 nm, 1 W cm-2 ) was effective in killing >90% of cells. The light-triggered Mn-CQDs@FA/Ce6 multifunctional hybrid can serve as a dual-modal FL/MRI probe and as an efficient PDT agent to detect and eradicate cancer cells remotely.

Cranberry Beans Derived Carbon Dots as a Potential Fluorescence Sensor for Selective Detection of Fe3+ Ions in Aqueous Solution.

Recently, synthesis, characterization, and application of carbon dots have received much attention. Natural products are the effectual carbon precursors to synthesize carbon dots with fascinating chemical and physical properties. In this study, the fluorescent sensor of carbon dots derived from cranberry beans without any functionalization and modification was developed. The carbon dots were prepared with a cheap, facile, and green carbon precursor through a hydrothermal treatment method. The synthetic process was toxic chemical-free, convenient, and environmentally friendly. To find the optimized synthetic conditions, the temperature, heating time duration, and carbon precursor weight were evaluated. The prepared carbon dots were characterized by UV light, transmission electron microscopy, Raman, Fourier transform infrared, UV-vis, and fluorescence spectroscopy. The resulting carbon dots exhibit stable fluorescence with a quantum yield of approximately 10.85%. The carbon dots emitted the broad fluorescence emission range between 410 and 540 nm by changing the excitation wavelength and were used for the detection of Fe3+ ions at the excitation of 380 nm. It is found that Fe3+ ions induced the fluorescence intensity quenching of the carbon dots stronger than other heavy metals and the Fe3+ ion detection can be achieved within 3 min. Spectroscopic data showed that the obtained carbon dots can detect Fe3+ ions within the wide concentration range of 30-600 µM with 9.55 µM detection limit.

A review on HCV inhibitors: Significance of non-structural polyproteins.

Hepatitis C virus (HCV) mortality and morbidity is a world health misery with an approximate 130-150 million chronically HCV tainted and suffering individuals and it initiate critical liver malfunction like cirrhosis, hepatocellular carcinoma or liver HCV cancer. HCV NS5B protein one of the best studied therapeutic target for the identification of new drug candidates to be added to the combination or multiple combination medication recently approved. During the past few years, NS5B has thus been an important object of attractive medicinal chemistry endeavors, which induced to the surfacing of betrothal preclinical drug molecules. In this scenario, the current review set limit to discuss research published on NS5B and few other therapeutic functional inhibitors concentrating on hit investigation, hit to lead optimization, ADME parameters evaluation, and the SAR data which was out for each compound type and similarity taken into consideration. The discussion outlined in this specific review will surly helpful and vital tool for those medicinal chemists investigators working with HCV research programs mainly pointing on NS5B and set broad spectrum identification of creative anti HCV compounds. This mini review also tells each and every individual compound ability related how much they are active against NS5B and few other targets.

Graphene oxide@gold nanorods for chemo-photothermal treatment and controlled release of doxorubicin in mice Tumor.

Graphene oxide (GO) is a close derivative of graphene has unlocked many pivotal steps in drug delivery due to their inherent biocompatibility, excellent drug loading capacity, and shows antibacterial, antifungal properties etc. We used a novel plant material called Gum arabic (GA) to increase the solubility of GO as well as to chemically reduce it in the solution. GA functionalized GO (fGO) exhibited increased absorption in near infra-red region (NIR) which was exploited in photothermal therapy for cancer. In order to understand the shape and size effect of GO which may affect their rheological properties, we have conjugated them with gold nanorods (GNRs) using in situ synthesis of GO@GNRs via seed mediated method. To the above conjugate, Doxorubicin (DOX) was attached at ambient temperature (28±2°C). The release kinetics of DOX with the effect of NIR exposure was also carefully studied via in vitro photothermal killing of A549 cell lines. The enhancement in NIR induced drug release and photothermal property was observed which indicates that the fGO@GNRs-DOX method is an ideal choice for chemotherapy and photothermal therapy simultaneously.

Folic Acid navigated Silver Selenide nanoparticles for photo-thermal ablation of cancer cells.

Photothermal ablation of the cancer cells is a non-invasive technique for cancer treatment, involving cellular assassination in presence of photothermal agent. We are reporting silver selenide (Ag2Se) nanoparticles for photothermal therapy using folic acid for selective targeting. The material, when exposed to 808nm laser, the temperature got boosted to 54°C in 6.5min, thus proving its potential for photothermal ablation. The material was highly biocompatible (95%) at highest concentration (10µg/mL) against A 549 cells. However, in presence of laser, the cellular killing was 55%. The mode of death was analyzed using MALDI-TOF MS.

Magnetofluorescent Carbon Dots Derived from Crab Shell for Targeted Dual-Modality Bioimaging and Drug Delivery.

We propose a one-pot microwave-assisted pyrolysis method for fabrication of magnetofluorescent carbon quantum dots (MFCQDs), using a combination of waste crab shell and three different transition-metal ions, Gd3+, Mn2+, and Eu3+, referred to as Gd@CQDs, Mn@CQDs, and Eu@CQDs, respectively. Chitin from waste crab shell acted not only as a carbon source but also as a chelating ligand to form complexes with transition-metal ions. Gd@CQDs exhibited a high r1 relaxivity of 4.78 mM-1·s-1 and a low r2/r1 ratio of 1.33, suggesting that they show excellent potential as a T1 contrast agent. Mn@CQDs and Eu@CQDs showed high r2 relaxivity values of 140.7 and 28.32 mM-1·s-1, respectively, suggesting their potential for use as T2 contrast agents. Further conjugation of Gd@CQDs with folic acid (FA) enabled specific targeting to folate receptor-positive HeLa cells, as confirmed via in vitro magnetic resonance and fluorescence imaging. Doxorubicin (DOX) was selected as a model drug for conjugation with FA-Gd@CQDs. The as-prepared nanocomposites showed significantly higher cytotoxicity toward HeLa cells than free DOX. No apparent cytotoxicity was observed in vivo (zebrafish embryos) or in vitro (cell viability), suggesting that MFCQDs show potential for development as diagnostic probes or theranostic agents.

Facile synthesis of gold/gadolinium-doped carbon quantum dot nanocomposites for magnetic resonance imaging and photothermal ablation therapy.

Composites of gold nanomaterials and imaging agents show promise in cancer therapy. Here we have demonstrated a rapid, facile, environmentally friendly, and organic solvent-free method for the synthesis of a gold/gadolinium-doped carbon quantum dot (Au/GdC) nanocomposite for magnetic resonance imaging (MRI) and photothermal ablation (PTA) therapy. The gadolinium-doped carbon quantum dots (Gd@CQDs) were synthesized using a one-pot, microwave-assisted method, and used as reducing and stabilizing agents to both form the Au/GdC nanocomposite and prevent its agglomeration. Formation of the Au/GdC nanocomposite is achieved by simple mixing of Gd@CQDs and a gold precursor, without the addition of any other reducing agents, surface passivating agents, surfactants, or organic solvents. The Au/GdC nanocomposite shows paramagnetism, surface plasma resonance in the near infrared region (NIR), and excellent photostability. Furthermore, it provides high longitudinal relaxivity (r1 = 13.95 mM-1 s-1), indicating its potential for use as a T1 contrast agent in MRI. Furthermore, in vitro and in vivo studies using HeLa cells and zebrafish embryos as cancer and animal cell models, respectively, confirmed the low toxicity and excellent biocompatibility of the Au/GdC nanocomposite. Notably, our results demonstrate the ability of the Au/GdC nanocomposite to efficiently destroy cancer cells using PTA. Therefore, this work reveals a simple and powerful strategy to fabricate an Au/GdC nanocomposite for MRI and photothermal ablation of cancer cells.

Rapid fabrication of carbon quantum dots as multifunctional nanovehicles for dual-modal targeted imaging and chemotherapy.

Herein, we synthesized an S, N, and Gd tri-element doped magnetofluorescent carbon quantum dots (GdNS@CQDs) within 10min by using a one-pot microwave method. Our results showed that these magnetofluorescent GdNS@CQDs have excellent fluorescent and magnetic properties. Moreover, GdNS@CQDs exhibited high stability at physiological conditions and ionic strength. These magnetofluorescent GdNS@CQDs were conjugated with a folic acid, denoted as FA-GdNS@CQDs, for targeting dual modal fluorescence/magnetic resonance (MR) imaging. The in vitro and in vivo studies confirmed the high biocompatibility and low toxicity of FA-GdNS@CQDs. FA-GdNS@CQDs enhanced the MR response as compared to that for commercial Gd-DTPA. The targeting capabilities of FA-GdNS@CQDs were confirmed in HeLa and HepG2 cells using in vitro fluorescence and MR dual modality imaging. Additionally, an anticancer drug, doxorubicin, was incorporated into the FA-GdNS@CQDs forming FA-GdNS@CQDs-DOX, which enables targeted drug delivery. Importantly, the prepared FA-GdNS@CQDs-DOX showed a high quantity of doxorubicin loading capacity (about 80%) and pH-sensitive drug release. The uptake into cancer cells and the intracellular location of the FA-GdNS@CQDs were observed by confocal laser scanning microscopy. We also successfully demonstrated in vivo fluorescence bio imaging of the FA-GdNS@CQDs, using zebrafish as an animal model. STATEMENT OF SIGNIFICANCE: In this manuscript, we reported a facial, rapid, and environmental friendly method to fabricate hetero atoms including gadolinium, nitrogen, and sulfur doped multi-functional magnetofluorescent carbon quantum dots (GdNS@CQDs) nanocomposite. These multifunctional GdNS@CQDs were conjugated with a folic acid for targeting dual modal fluorescence/magnetic resonance imaging. Additionally, an anticancer drug, doxorubicin, was incorporated into the nanocomposite forming FA-GdNS@CQDs-DOX, which enables targeted drug delivery. We have developed GdNS@CQDs with integrated functions for simultaneous in vitro cell imaging, targeting, and pH-sensitive controlled drug release in HeLa cells. Furthermore, we successfully demonstrated the use of this material for in vivo fluorescence imaging, using zebrafish as an animal model.

Fluorimetric detection of pathogenic bacteria using magnetic carbon dots.

A novel and facile approach of pathogenic bacteria detection, which utilizes fluorescent sensing and bacteria capture with Magnetic carbon dots (Mag-CDs), was proposed in this work. Magnetic nanoparticles were synthesized and then decorated with C-dots, and further functionalized with amine groups (chitosan). In this way, bacteria were strongly anchored on the hybrid material Mag-CDs for highly sensitive fluorescent detection. The Mag-CDs were characterized by UV-vis, FT-IR spectra, TEM images, XRD, and EDX. The characterizations validate the fabrication of amine-Mag-CDs and the promising applications of this material. Fluorescence spectroscope and MALDI-MS were used for the detection and identification of bacterial strains, respectively. The limit of detection for Staphylococcus aureus and Escherichia coli was found to be 3 × 10(2) and 3.5 × 10(2) cfu mL(-1), respectively. With these encouraging results, it is expected that it would open revenues for promising applications of Mag-CDs nanomaterial.