Carbon Dot Nanoparticles Research Articles

Carbon dots nanoparticles derived from showy Asian grapes (Medinilla speciosa) for free radical scavenger

Carbon dot nanoparticles (CNPs) were synthesized from the peels of showy Asian grapes (Medinilla speciosa) using microwave irradiation for free radical scavenging. The optimal emission and absorption intensities were achieved with a 50-min irradiation duration, at wavelengths of 430 nm and 267 nm, respectively. XRD analysis revealed characteristic peaks at angles of 26.37° and 29.63°. FTIR analysis indicated that antioxidant potential is attributed to hydroxyl and carboxyl groups on the CNPs’ surface. TEM images showed diameters ranging from 2 nm to 8 nm. The CNPs exhibited 73.82% antioxidant activity at 5 mg/mL, with an IC50 value of 6.89 ppm, indicating strong antioxidant activity. Additionally, the CNPs demonstrated good storage stability, suggesting potential applications in food supplements and biomedical materials.

Molecular Targets and Nano-Technological Approaches in the Treatment of Hepatic Carcinoma.

Liver cancer is a leading cause of cancer-related mortality, with about one million people losing their lives each year. The disease becomes even more dangerous when tumors cannot be removed through surgery. Globally, hepatocellular carcinoma (HCC) ranks third in terms of fatality rates among liver cancers. It is also the most frequent type of liver cancer. Due to the high mortality rate associated with this malignancy, it is a hotspot for researchers looking to improve treatment methods. Nanotechnology plays an important part in these at-tempts. Various types of nanoparticles (NPs) have been investigated for their ability to fight liver cancer. NPs are a vast class of materials. The article details the efforts made to include inorganic NPs, such as silver, gold, metal oxide, platinum, calcium, selenium, and other un-common materials into drug delivery systems (DDS) for therapeutic, carrier, or imaging pur-poses. This review discusses the function of carbon-based NPs in DDS for the treatment of liver cancer, including polymeric, polysaccharide, lipid, and carbon dot NPs, all of which have been extensively researched for this purpose. The purpose of this review is to provide a con-cise overview of recent developments in the field of HCC based on current research and clini-cal diagnosis and treatment guidelines. Further goals include elucidating the current state of nanomaterials research, its limitations, and the potential for future advancements in the field, as well as the use of nanotechnology in the detection and treatment of HCC.

Impact of green carbon dot nanoparticles on seedling emergence, crop growth and seed yield in blackgram (Vigna mungo L. Hepper)

Carbon Dots (CDs) were synthesized from peanut shells (PNS) through pyrolysis and characterized using FTIR, XRD, HRTEM and BET analysis revealing an average size of 2–5 nm with amorphous nature. Synthesized PNS-CDs was employed both as priming and foliar agent for enhancing seed quality and crop productivity in blackgram (Vigna mungo L. Hepper). Different concentrations ranging from 50, 100, 200, 300, 400, 500 and 1000 ppm was used for seed priming and 5, 10, 15, 20, 25, 50, 75 and 100 ppm were given as foliar spray on 30th and 45th days after sowing (DAS). On accounting the best seed priming and foliar spray concentrations, field trial was conducted to validate the optimistic effect of PNS-CDs on blackgram crop productivity. Results revealed that priming with 200 ppm for 3 h exhibited maximum seed imbibition (54%), germination (88%) and vigour index (3165). Whereas, foliar spray with 50 ppm expressed significant improvement in leaf area index (2.6), total chlorophyll (2.70 mg/g), total soluble protein (71 mg/g), Number of nodules/plant (138), seed yield/plant (8.7 g) and 100 seed weight (5 g). The impact of PNS-CDs treatments resulted in increased photosynthetic rate (12.45 µmol CO2 m−2s−1), transpiration rate (3.13 mmol H2O/m−2s−1), stomatal conductance (0.55 mol H2O/m−2s−1) and internal leaf CO2 concentration (652 µmol CO2 m−2s−1) which ultimately enhanced the photosynthetic efficiency of plants. It has also exhibited a promising effect on the resultant seed in which the combination seed priming (200 ppm) followed by foliar spray (50 ppm) recorded maximum 100 seed weight (4.19 g), germination (97%) and vigour index (3019). Thus, this study highlights the promising role of PNS-CDs as a sustainable and effective agricultural nanomaterial, offering a novel approach to utilize the agricultural waste and also to enhance the crop productivity through advanced non-chemical approach.

Green synthesis of carbon dots nanoparticles from edible swiftlet nest and evaluation of their antioxidant activity

Edible swiftlet nest (ESN) confers various health benefits to humans, including immune system enhancement, anti-inflammatory properties, bone strengthening, and antioxidative effect. ESN is notably rich in protein and minerals, with its proteins serving as non-enzymatic antioxidants capable of binding free radicals. However, the antioxidant capacity of ESN is comparatively lower than that of other free radical scavengers, such as carbon dots nanoparticles (CNPs). CNPs features charged ligands on their surface that act as electron donors for free radical binding. The presence of the carbon chain forming proteins in ESN suggests their potential as the primary source for CNPs formation. The enhancement of hydroxyl groups and delocalized electrons is imperative for enhancing the antioxidant activity of ESN. This study aims to enhance the antioxidant activity of ESN by converting it into CNPs nanoparticles. The results demonstrated the effective synthesis of CNPs from the ESN solution using microwave methods. This was evidenced by XRD patterns indicating CNPs formation, and an average particle size of 4.86 nm as indicated by TEM analysis. The optimal microwave heating duration of 30 min yielded CNPs with a prominent emission spectrum peak at 425 nm and significantly high intensity. Absorbance data revealed the presence of C=C bonds, consistent with aromatic CNPs bonds observed in FTIR studies. CNPs possessed hydroxyl and carboxyl linkages, suggesting their potential as antioxidants. The percent inhibition results indicated that CNPs exhibited a substantial percentage (62.5%) at a concentration of 50 mg ml−1. The free radical scavenging activity of the CNPs significantly elevated compared to ESN.

Exploring the therapeutic potential of Aloin: unraveling neuroprotective and anticancer mechanisms, and strategies for enhanced stability and delivery

We investigate the therapeutic potential of Aloin A and Aloin B, two natural compounds derived from Aloe vera leaves, focusing on their neuroprotective and anticancer properties. The structural differences between these two epimers suggest that they may exhibit distinct pharmacological properties. Our investigations revealed that both epimers are not stable in aqueous solution and tend to degrade rapidly, with their concentration decreasing by over 50% within approximately 12 h. These results underscore the importance of addressing issues such as the need for encapsulation into effective drug delivery systems to enhance stability. ThT fluorescence experiments showed that neither compound was able to inhibit Aβ amyloid aggregation, indicating that other mechanisms may be responsible for their neuroprotective effects. Next, an equimolar mixture of Aloin A and Aloin B demonstrated an ability to inhibit proteasome in tube tests, which is suggestive of potential anticancer properties, in accordance with antiproliferative effects observed in neuroblastoma SH-SY5Y and HeLa cell lines. Higher water stability and increased antiproliferative activity were observed by encapsulation in carbon dot nanoparticles, suggesting a promising potential for further in vivo studies.

Nanopriming with selenium doped carbon dots improved rapeseed germination and seedling salt tolerance

Soil salinity is a big environmental issue affecting crop production. Although seed nanopriming has been widely used to improve seed germination and seedling growth under salinity, our knowledge about the underlying mechanisms is still insufficient. Herein, we newly synthesized selenium-doped carbon dots nanoparticles coated with poly acrylic acid (poly acrylic acid coated selenium doped carbon dots, PAA@Se-CDs) and used it to prime seeds of rapeseeds. The TEM (transmission electron microscope) size and zeta potential of PAA@Se-CDs are 3.8 ± 0.2 nm and −30 mV, respectively. After 8 h priming, the PAA@Se-CDs nanoparticles were detected in the seed compartments (seed coat, cotyledon, and radicle), while no such signals were detected in the NNP (no nanoparticle control) group (SeO2 was used as the NNP). Nanopriming with PAA@Se-CDs nanoparticles increased rapeseeds germination (20%) and seedling fresh weight (161%) under saline conditions compared to NNP control. PAA@Se-CDs nanopriming significantly enhanced endo-β-mannanase activities (255% increase, 21.55 µmol h−1 g−1 vs. 6.06 µmol h−1 g−1, at DAS 1 (DAS, days after sowing)), total soluble sugar (33.63 mg g−1 FW (fresh weight) vs. 20.23 mg g−1 FW) and protein contents (1.96 µg g−1 FW vs. 1.0 µg g−1 FW) to support the growth of germinating seedlings of rapeseeds under salt stress, in comparison with NNP control. The respiration rate and ATP content were increased by 76% and 607%, respectively. The oxidative damage of salinity due to the over-accumulation of reactive oxygen species (ROS) was alleviated by PAA@Se-CDs nanopriming by increasing the antioxidant enzyme activities (SOD (superoxide dismutase), POD (peroxidase), and CAT (catalase)). Another mechanism behind PAA@Se-CDs nanopriming improving rapeseeds salt tolerance at seedling stage was reducing sodium (Na+) accumulation and improving potassium (K+) retention, hence increasing the K+/Na+ ratio under saline conditions. Overall, our results not only showed that seed nanopriming with PAA@Se-CDs could be a good approach to improve salt tolerance, but also add more knowledge to the mechanism behind nanopriming-improved plant salt tolerance at germination and early seedling growth stage.

Development of active packaging material based on polycaprolactone/hydroxypropyl methylcellulose nanofibers containing carbon dot nanoparticles for meat preservation

This work demonstrates the feasibility of using a combination of biodegradable polycaprolactone (PCL) and natural-based hydroxypropyl methylcellulose (HPMC) polymers containing carbon dots (CDs) for food packaging applications. CDs were synthesized using the insoluble portion of Zedo gum. The 5% and 15% concentrations of bare Zedo CDs (Z-CD) and nitrogen and sulfur co-doped CDs (TZ-CD) were chosen for incorporation into PCL/HPMC nanofibers (NFs). The PCL/HPMC/Z-CD15% and PCL/HPMC/TZ-CD15% demonstrated improved tensile strength (12.88 and 15.01 MPa), water solubility (30.20 and 42.36%), and water vapor transmittance (0.62 and 0.71 g mm/m2 h kPa)), respectively. When comparing the release of CDs in 10%, 50%, and 95% ethanolic solutions, it was found that TZ-CD released more rapidly than Z-CD from NFs in all three simulants. The CDs-added NFs exhibited potent antioxidant activity (80.5%). More significant antimicrobial activity against S. aureus was observed compared to E. coli. Additionally, reductions in total volatile basic nitrogen and thiobarbituric acid values indicated that beef covered with PCL/HPMC/TZ-CD15% and PCL/HPMC/Z-CD15% NFs had an extended shelf life of more than five days. In conclusion, PCL/HPMC/Z-CD15% and PCL/HPMC/TZ-CD15% NFs can be used as promising biodegradable packaging materials to enhance the shelf life of meat products.

A novel approach to Hg2+ determination in water samples using carbon dots based on paper and fluorescence digital image analysis

AbstractBACKGROUNDThis work proposes the use of a simple, inexpensive method for the hydrothermal synthesis of fluorescent carbon dot nanoparticles (CDs) from rice starch aimed at the determination of Hg2+ in water. The proposed method involved using a paper‐based analytical device coupled to a 3D plate, with a UV‐LED chamber and a smartphone for the acquisition and analysis of the fluorescence digital images of the CDs.RESULTSThe size of the carbon dots ranged from 0.5 to 3 nm, with an average particle size of ~1 nm. The functionalization of carbon dots with methimazole allowed a high selective for Hg2+ determination. The results obtained showed a linear response R2 of 0.997 and Hg2+ concentration in the range of 0.5–45.0 μmol L−1 with a limit of detection and limit of quantitation of 0.23 and 0.62 μmol L−1, respectively. The results of the study show that there were no significant differences, at 95% confidence level, between the data obtained from the application of the proposed method and the reference method.CONCLUSIONThe proposed method is in line with the principles of green chemistry, as it involves the use of renewable sources for starch extraction and a hydrothermal synthesis process that does not employ toxic reagents. In addition, the method employs only 15 μL reagent/sample. © 2024 Society of Chemical Industry (SCI).

Synthesis of Carbon Dot Nanoparticles (C-Dot) from Seeds and Seedpods of Kesumba Keling (Bixa orellana) using Hydrothermal and Solvothermal Methods

C-dot is a 0-dimensional nanoparticle with photoluminescence properties and can be synthesized from plants, such as the Kesumba Keling plant. Kesumba Keling contains a red pigment sourced from the bixin and norbixin dyes containing functional groups like ‒COOH and ‒COO‒. These functional groups are anticipated to enhance the luminescence intensity produced by C-dot. This research focuses on synthesizing C-dots from Kesumba Keling seeds and seedpods using hydrothermal and solvothermal methods. It also involves an analysis of how different solvents and passivation agents affect the luminescence of C-dots, along with a comparison of the resulting fluorescent colors. The highest yield, at 73.26%, was achieved when using Kesumba Keling seedpods and ethanol as the solvent without adding urea. Furthermore, C-dots synthesized using ethanol as the solvent display a stronger luminescent glow compared to those produced using double-distilled water as the solvent. Additionally, all C-dots synthesized in this study emit a blue luminescence. Characterizing C-dots using a UV-Vis spectrophotometer reveals absorption peaks at two different wavelengths: 260‒280 nm and 320‒340 nm. These absorption peak results align with C-dot characteristics, as confirmed by Fourier transform infrared spectrophotometry. When comparing the intensity of C-dots, those derived from Kesumba Keling peel using the double-distilled water solvent with the addition of urea exhibit a higher intensity (measuring at 0.99) than C-dots obtained from Kesumba Keling peel using ethanol as a solvent with added urea. The solvothermal method is deemed the most effective for C-dot synthesis, as it yields the highest luminescence intensity, accompanied by an emission wavelength shift to 491.65 nm.

Nitrogen doped carbon dots as a photocatalyst based on biomass. A life cycle assessment

The effectiveness of various transition metal phosphate-based acid catalysts, including vanadium and niobium, in the hydrothermal synthesis of carbon dots (CDs), has been assessed. Two sources of carbohydrates were employed for this: commercial xylose and liquor of xylose produced by processing olive pits. Catalysts were identified using the NH3-TPD, DTA/TG, XRD, and XPS techniques. The reaction was conducted for 4 h at a temperature of 180 °C. The existence of such nanoparticles, regardless of the carbohydrate source, was confirmed by an analysis of the features and characteristics of CDs nanoparticles. N-doped CDs with increased fluorescence were also created at the same time using a similar hydrothermal technique, and their photocatalytic activity was investigated. A Life Cycle Assessment (LCA) was conducted for both syntheses with the goal of comparing the environmental effects of the synthesis from commercial xylose to the synthesis from biomass. It was revealed that, although energy is the primary driver of both synthesis pathways' effect categories, the fundamental variations that seem to determine their relative sustainability are connected to the nature of the carbon precursor. Regarding the latter, it is determined that electricity has the greatest environmental impact.

Development of a Modified Electrode with N-doped Carbon Dots for Electrochemical Determination of 17α-ethinylestradiol

This work aims to develop a modified electrode with N-doped carbon dots (CPE/N-CD) for the voltammetric detection of 17α-ethinylestradiol (EE2) in solution. N-doped carbon dot nanoparticles (N-CD) were synthesized using citric acid and urea as the nitrogen source. The N-doped carbon dots were characterized by absorption and emission spectroscopy in the ultraviolet and visible regions, electronic absorption spectroscopy in the infrared region, and Raman Spectroscopy, which showed evidence of the formation of the material. Electrochemical analyses were conducted utilizing Differential Pulse Voltammetry (DPV). After optimization of electrochemical parameters, a calibration plot was produced for the sensor, demonstrating a linear range of 0.01 to 0.80 μmol L-1 (R2 = 0.9969). Additionally, the sensor exhibited a detection limit (LOD) of 0.59 nmol L-1 and a quantification limit (LOQ) of 2.00 nmol L-1. The studies on reproducibility and repeatability revealed RSDs of 1.63% and 3.61% respectively. The results obtained using CPE/N-CD indicate that the developed electrode exhibits excellent analytical performance, making it suitable for identifying and quantifying EE2 in solution.

Synthesis and characterization of carbon dots nanoparticles for detection of ascorbic acid

Hydrothermal method has been employed for the synthesis of carbon dots (CDs) nanoparticles at 180 °C. CDs were characterized by powder x-ray diffraction (XRD), FT-IR, electron microscopy, thermo-gravimetric analysis (TGA), UV–visible and fluorescence spectroscopy. XRD results reveal the formation of CDs. Electron microscopic studies show the spherical shape of CDs without apparent aggregation. Optical absorption measurements indicate a direct bandgap of 4.6ev. The electrochemical studies were conducted for the detection of ascorbic acid (A.A.) using cyclic voltammetry (CV) and differential pulse voltammetry (DPV) measurements.

Efficiency Enhancement of Heat Transfer Fluids by Using Carbon Dots Nanoparticles Derived From Aloe Vera

Modern technological progress in transportation, medical, electronics and HVAC systems has resulted in an extreme need for a performance-enhanced heat transfer system. Heat transfer employing a flowing fluid is most used, and the thermal properties of liquids play a decisive role in heating and cooling applications in industrial processes. The thermal conductivity of a liquid is an important physical property that decides its heat transfer performance. Conventional heat transfer fluids have inherently poor thermal conductivity, making them inadequate for ultra-high heat transfer applications. Nanofluids are a new class of liquids whose properties are controllable by adding nanoparticles. A great deal of attention has been drawn to their enhanced heat transfer characteristics relative to that of pure fluid. This paper synthesizes three various Nano Fluids and experimentally compares their heat transfer capabilities using a shell and tube heat exchanger setup. An attempt is made to suggest applications for enhanced heat transfer. Al2O3 Nanofluid is compared with Nanofluid containing carbon dots derived from Aloe vera, and it has been found that carbon. Aloe vera yields more heat transfer

High sensitive assay of formaldehyde using resonance light scattering technique based on carbon dots aggregation

Formaldehyde (FA) is widely used in industry and also common in daily life. Finding an efficient method to determine FA is quite an industrial challenge. Herein, a novel method based on a resonance light scattering (RLS) technique was developed for the detection of FA with high sensitivity. Carbon dots (CDs) were used as RLS probes. CDs were obtained via one-pot solvothermal treatment from o-phenylenediamine. CDs showed yellow fluorescence with a quantum yield of 0.41. Due to the multiple amino groups on the surface of CDs, FA can be captured easily by formation of a covalent C = N bond based on the Schiff-base reaction. Owing to the covalent crosslinking, CD nanoparticles aggregated, and even formed precipitate. The aggregation of CDs induced RLS enhancement, where the RLS increment was linearly related to the concentration of FA ranging from 4 nM to 1.6 mM, with a limit of detection (LOD) of 1.6 nM. In comparison with many previous reports, the present RLS method showed a wider linear range and lower LOD. Furthermore, the RLS system was successfully used to detect FA in real food samples. The proposed system has prospective applicability in the detection of FA in food fields.

Deconvolution of photoluminescence spectra and electronic transition in carbon dots nanoparticles from microcrystalline cellulose

Carbon dots (CDs) are nanomaterials with promising applications in several areas such as optoelectronics and biomedicine due to their low toxicity and strong luminescence intensity. Understanding the emission and bandwidth of the fluorescence spectrum is still a challenge in the scientific community due to the dependence of emission on the excitation wavelength. In this work, the photoluminescence properties of carbon dots obtained from microcrystalline cellulose (MCC) were studied. The optical properties were studied through measurements of photoluminescence (PL), photoluminescence excitation (PLE), and absorption. Systematic adjustments were made through Gaussian deconvolution of the PL spectrums and the coupling between electronic states was analyzed through PLE and optical absorption measurements. From the Gaussian adjustments, bandwidth values of ∼25 nm and ∼100 nm were found for the emission associated with the core and the surface states respectively, these values are consistent with the bandwidth of the PLE spectra with tuned detection in these states. As evidenced by the results, there are contributions from the core and surface functional groups in the luminescence emission of CDs. Furthermore, with recent analyzes that attribute the radiative emission of CDs only to the surface trap states, we observed that the core present emission and absorption of light for samples with specific pH and reaction times. These results should contribute to the understanding of the electronic transitions of CDs for applications related to the luminescent optical properties of these nanomaterials.

Preparation, characterization of green tea carbon quantum dots/curcumin antioxidant and antibacterial nanocomposites

Carbon quantum dots with good biocompatibility can be used as nanomaterial carriers to improve the bioavailability of curcumin. In this paper, green tea was used as raw material to provide a green synthesis method for preparing carbon dots nanoparticles, and Curcumin was loaded to prepare carbon quantum dots/Curcumin nanocomposites (CQDs/Cur). A series of characterization methods were used to study the morphology and chemical structure of composite nanoparticles. The tea carbon dots had the characteristics of excitation wavelength dependence, salt solution stability and light stability. Finally, the antioxidant activities of CQDs/Cur nanocomposites were investigated by DPPH, ABTS•+, hydroxyl radical, metal ion chelating and reducing power assays. The compound system not only improved the antioxidant performance of curcumin, but also retained the antibacterial activity of curcumin. These results suggested that tea carbon quantum dots loaded with curcumin had the potential to be developed as natural antioxidants and antibacterial agents.

Carbon dot crosslinking towards mechanochemically and photochemically induced fluorescence resonance energy transfer

Mechanochromism in polymers has attracted great interests in recent years. Herein, we develop a mechanochromic elastomer carrying spiropyran mechanophores in the chain and mechanoresponsiveness of elastomer is enhanced by embedding luminescent carbon dot ( CD ) nanoparticles as crosslinkers and energy donor in fluorescence resonance energy transfer (FRET). Compared with the control with physically blended CD , CD crosslinked elastomer exhibit excellent daylight and fluorescent colors change under stretching. The mechanochemically induced fluorescence change is a result of FRET between CD nanoparticles and the activated merocyanine. The control with physically blended CD nanoparticles shows low FRET in stretching due to lower fraction of spiropyran activation as a result of lower mechanical properties. Furthermore, the CD crosslinked elastomer has already been applied in rewritable mechanochemical and photochemical recording or printing. Our demonstration shows that interfacial chemical bonding plays a critical role in the reinforcement of mechanical properties for polymer composites and may exhibit great potential in the study of the acceleration of mechanoresponsiveness of polymer and multi-responsiveness of polymer nanocomposites. • Mechanochromic elastomers were prepared with SP being in chain and crosslinked by CD. • CD as nanofiller and energy donor improves mechanochromism of nanocomposites by FRET. • Elastomers enable use in rewritable mechano- and photochemical recording/printing.

Development of carbon dots sensor dipstick from sugarcane bagasse agricultural waste toward all-cellulose-derived tetracycline sensor

Tetracycline antibiotic has been widely used in veterinary and aquafarming medicines to prevent and treat infectious diseases. However, the overall use of tetracycline results in its accumulation in the organism organs, which then migrates to food and eventually increases the risk of developing various diseases. As one of the most well-known contaminants, sugarcane bagasse (SCB) agricultural waste has been a serious problem worldwide. In order to develop luminous carbon dots doped with nitrogen (NCDs), a simple and environmentally friendly approach was devised to reprocess sugarcane bagasse agricultural waste. A passivating agent, ammonium hydroxide (NH4OH), was used during the hydrothermal carbonization of NCDs in a single-pot procedure. Carbon dots nanoparticles (5–8 nm) embedded in cellulose paper assay were used to prepare the testing strip. With an emission wavelength of 447 nm upon excitation at 355 nm and, NCDs displayed a quantum yield (QY) of up to 24.81%. As a result of the inner filter effect (IFE), the fluorescence of NCDs was clearly quenched by tetracycline, demonstrating their exceptional tetracycline selectivity. The detection limit was set in the concentration range of 0–110 μM. Tetracycline is detected and measured using the current cellulose paper strip, which contains a fluorescent signal that could be turned off to eliminate the signal. The fluorescence quenching feature of cellulose carbon dots in the existence of tetracycline affects the fluorescence activity of the paper strip assay.

Function-adaptive clustered nanoparticles reverse Streptococcus mutans dental biofilm and maintain microbiota balance

Dental plaques are biofilms that cause dental caries by demineralization with acidogenic bacteria. These bacteria reside inside a protective sheath which makes any curative treatment challenging. We propose an antibiotic-free strategy to disrupt the biofilm by engineered clustered carbon dot nanoparticles that function in the acidic environment of the biofilms. In vitro and ex vivo studies on the mature biofilms of Streptococcus mutans revealed >90% biofilm inhibition associated with the contact-mediated interaction of nanoparticles with the bacterial membrane, excessive reactive oxygen species generation, and DNA fragmentation. An in vivo examination showed that these nanoparticles could effectively suppress the growth of S. mutans. Importantly, 16S rRNA analysis of the dental microbiota showed that the diversity and richness of bacterial species did not substantially change with nanoparticle treatment. Overall, this study presents a safe and effective approach to decrease the dental biofilm formation without disrupting the ecological balance of the oral cavity.

Polymeric Blends of Carboxymethyl Cellulose and Sodium Alginate Containing Functionalized Carbon Dots Result in Stable and Efficient Fluorescent Films for Silver and Iron (III) Sensing

A fluorescent film using a polymeric blend of carboxymethyl cellulose and alginate with functionalized carbon dots (CDs) incorporated to detect Ag+ and Fe3+ was reported for the first time. CDs were hydrothermally obtained from the cambuci fruit. The film and the carbon dots obtained were characterized by transmission electron microscopy, Fourier transform infrared spectrophotometer, x-ray diffraction, Raman spectroscopy, atomic force microscopy, thermogravimetric analysis, differential scanning calorimetry, fluorescence spectroscopy, diffuse reflectance spectroscopy, mechanical tests, Zeta potential, wettability, and swelling. Also, ionic stability and fluorescence were evaluated. The carbon dots obtained had an average diameter of 4.12 nm and a quantum yield of 4.17%. The polymeric blend with CDs nanoparticles exhibited improved thermal stability and tensile mechanical properties when compared to a pristine blend. The films presented an improved detection performance for Ag+ and Fe3+, considering synthetic solutions and real water samples (drinking water and lake water). The dynamic detection range for silver and iron (III) ions was 50–500 μM and the detection limits were 29.18 μM and 23.66 μM, respectively. Therefore, the film presented acceptable performance for detecting Ag+ and Fe3+ in synthetic solutions and real samples. This is a promising alternative compared to conventional techniques due to the easy synthesis, satisfactory analytical performance, stability, eco-friendly, and low-cost.