Carbon dots derived from Poria cocos polysaccharide as an effective"on-off"fluorescence sensor for chromium(Ⅵ)detection / 药物分析学报

Chromium is a harmful contaminant showing mutagenicity and carcinogenicity.Therefore,detection of chromium requires the development of low-cost and high-sensitivity sensors.Herein,blue-fluorescent carbon quantum dots were synthesized by one-step hydrothermal method from alkali-soluble Poria cocos polysaccharide,which is green source,cheap and easy to obtain,and has no pharmacological ac-tivity due to low water solubility.These carbon quantum dots exhibit good fluorescence stability,water solubility,anti-interference and low cytotoxicity,and can be specifically combined with the detection of Cr(Ⅵ)to form a non-fluorescent complex that causes fluorescence quenching,so they can be used as a label-free nanosensor.High-sensitivity detection of Cr(Ⅵ)was achieved through internal filtering and static quenching effects.The fluorescence quenching degree of carbon dots fluorescent probe showed a good linear relationship with Cr(Ⅵ)concentration in the range of 1-100 μM.The linear equation was F0/F=0.9942+0.01472[Cr(Ⅵ)](R2=0.9922),and the detection limit can be as low as 0.25 μM(S/N=3),which has been successfully applied to Cr(Ⅵ)detection in actual water samples herein.

Simple synthesis of photoluminescent carbon dots from a marine polysaccharide found in shark cartilage

BACKGROUND: For more than a decade, water-soluble, eco-friendly, biocompatible, and low-toxicity fluorescent nanomaterials have received considerable attention for their numerous in vivo and in vitro applications in biomedical imaging, disease diagnostics, and environmental monitoring. Owing to their tunable photoluminescence properties, carbon-based luminescent nanomaterials have shown great potential in bioimaging, photocatalysis, and biosensing among other applications. RESULTS: Marine environments provide excellent resources for the fabrication of these nanomaterials, because many marine organisms contain interesting trigger organic compounds that can be used as precursors. Herein, we synthesize multi-color emissive carbon dots (CDs) with an intrinsic photoluminescence quantum yield of 20.46%. These nanostructures were achieved through the one-step hydrothermal treatment of marine polysaccharide chondroitin sulfate, obtained from shark cartilage, in aqueous solution. CONCLUSIONS: We successfully demonstrate the low toxicity of our marine resource-derived CDs in zebrafish, and provide an initial assessment of their possible use as a bioimaging agent. Notably, the newly synthesized CDs localize in the intestines of zebrafish larvae, thereby indicating their biocompatibility and potential use as in vivo dyes.

Inhibitory effects of zinc-doped carbon dots combined with blue light radiation on growth and biofilm formation of Staphylococcus aureus / 吉林大学学报(医学版)

Objective: To synthesize the zinc-doped carbon dots (CDs) by hydrothermal method and to observe the inhibitory effects of zinc-doped CDs combined with blue light on the formation of Staphylococcus aureus (S. aureus), and to explore the related mechanism. Methods: The zinc-doped (CDs) were synthesized by hydrothermal method, and the characteristics were observed by transmission electron microscope ( TEM). fluorescence spectrometer and Fourier transform-infrared spectrometer (FT-IR). The experiment was divided into blank control group. CDs group, blue light radiation group, and CDs +blue light radiation group. The cells in CDs group were treated with different concentrations (50. 75. 100 mg • L ' ) of CDs. the cells in blue light radiation group were irradiated with blue light for 10. 20. and 40 min. the cells in CDs + blue light radiation group were treated with CDs combined with blue light, and the cells in blank control group were only treated by culture medium in the dark. CCK-8 assay was used to determine the proliferation rates of the L929 and MC3T3-E1 cells. The reactive oxygen species were scavenged by adding N-acetylcysteine (NAC) in the best bacteriostatic effect group (100 mg • L ' CDs group), and the experiment was divided into contro group. 100 mg • L ' CDs group. 0.5 mmol • L 'NAC group, and 0.5 mmol • L ' NAC+ 100 mg • L ' CDs group. The concentrations of the bacteria suspension in various groups were detected by spectrophotometer, the bacterial biofilm formation amounts of S. aureus in various groups were detected by crystal violet staining, and the plate count method was used to record the colony counts in various groups. Results: The TEM results showed that the particle size of the zinc-doped CDs constructed successfully was about 1. 8 nm. The fluorescence spectra showed that the optimum excitation wavelength of CDs was 342 nm and the optimum emission wavelentgh was 450 nm. The FT-IR spectrum showed that CDs had hydroxyl. carboxy. amino and other functional groups. TheCCK-8 assay results showed that after co-culture for 24 h. the proliferation rates of L929 and MC3T3-E1 cells in 100 mg • L ' CDs group were up to 80%. Compared with blank control group, the concentrations of bacteria solution in blue light radiation for 20 and 40 min groups were decreased ( P<∗0. 05 or P<.0. 01). the biofilm formation amount of S aureus was decreased after blue light radiation for 40 min ( P<0. 01). Compared with blue light radiation group, the concentration of bacteria solution and the biofilm formation amount of S. aureus in CDs + blue light radiation (10 min) group were decreased after blue light radition for 10 min ( P<0. 01). Compared with 100 mg • L ' CDs group, the concentration of bacteria solution and the biofilm formation amount of bacteria in 0. 5 mmol • L 1 NAC+100 mg • L ' CDs group were increased (P<0.01). Conclusion: Zinc-doped CDs combined with blue light can inhibit the growth of S aureus and the biofilm formation by photocatalysis effectly.

Progress on carbon dots research and its application prospect in Cervi Cornu Pantotrichum / 中草药

Carbon dots are an emerging nanomaterial with excellent fluorescent properties. Compared with traditional organic dyes and semiconductor quantum dots, carbon dots possess advantages of low toxicity and good biocompatibility. At present, carbon dots are widely used in many fields such as analytical detection, fluorescence imaging and drug delivery. Cervi Cornu Pantotrichum, a rare mammalian organ with ability of full regeneration, has been used as famous traditional Chinese medicine. The biological functions and efficacy of Cervi Cornu Pantotrichum are closely related to their chemical constituents. In this paper, we briefly reviewed the progress of carbon dots research in fluorescence detection, fluorescence imaging and phototherapy, carried out the bioimaging and cell cytotoxicity test by carbon dots, and discussed the feasibility of carbon dots in biological features and chemical composition analysis of Cervi Cornu Pantotrichum.

Synthesis of a new type of carbon dots by pyrolysis of human hair using motor oil as a dispersant and their biological effects / 中草药

Objective: New type of nano-carbon dots were found after pyrolysis of human hair using motor oil as a dispersant and the biological effect of these carbon dots was evaluated by animal experiments. Methods: High-temperature pyrolysis was used to carbonize human hair and motor oil, and the carbonized products were extracted, filtered, and dialyzed to obtain a new type of water-soluble substance, carbon dots, named JYRF-CDs. JYRF-CDs were characterized using transmission electron microscopy (TEM) and high-resolution TEM, as well as ultraviolet-visible, fourier transform infrared, fluorescence spectroscopy and X-ray photoelectron spectroscopy (XPS). CCK-8 toxicity test using RAW264.7 cells was used to evaluate the safety of JYRF-CDs and the biological effects of the JYRF-CDs were evaluated by mouse ear swelling experiments and mouse acetate writhing experiments. Results: These JYRF-CDs were nearly spherical and well separated from each other, with a size distribution range of 1.8-3.6 nm, the CDs had a lattice spacing of 0.219 7 nm. The results of cytotoxicity experiments showed that JYRF-CDs had low toxicity, and the results of animal experiments showed that JYRF-CDs had good anti-inflammatory and analgesic effects. Conclusion: In this study, new type of carbon dots, JYRF-CDs, were discovered after pyrolyzing human hair with motor oil as a dispersant for the first time. Taking JYRF-CDs as a breakthrough, the material base of carbonization products after pyrolysis of human hair by high-temperature pyrolysis using motor oil as a dispersant was more clearly explained, providing a new method for the research of nano compounds.

Synthesis of highly fluorescent carbon dots from lemon and onion juices for determination of riboflavin in multivitamin/mineral supplements / 药物分析学报

In this work, lemon and onion biomasses commonly found in street markets are for the first time used to develop a facile, fast and low-cost one-step microwave-assisted carbonization method for synthesis of highly fluorescent carbon dots (CDs). The structure and optical properties of CDs were investigated by TEM, XRD, XRF, UV-Vis, FTIR, and fluorescence spectroscopy. CDs displayed satisfactory optical pro-prieties, a high quantum yield of 23.6％, and excellent water solubility, and the particle size was 4.23-8.22 nm with an average diameter of 6.15 nm. An efficient fluorescent resonance energy transfer (FRET) between the CDs and riboflavin was achieved with CDs acting as donor and riboflavin as acceptor. A linear relationship between FRET and the riboflavin concentration from 0.10 to 3.0 μg/mL was observed, allowing the development of an accurate and fast analytical method to determine this vitamin in multivitamin/mineral supplements. Despite the potential interferences in these supplements, CDs were selective for riboflavin under optimized conditions. A paired t-test at a 95％ confidence level indicated no statistically significant difference between the proposed and the reference methods. Recovery test presented values ranged from 96.0％ to 101.4％. The limit of detection and relative standard deviation were estimated at 1.0 ng/mL and <2.6％ (n = 3), respectively. CDs were successfully synthesized in a domestic microwave oven (1450 W, 6 min), presenting satisfactory parameters when compared with results of other studies reported in the literature, suggesting that the proposed method is a potentially useful method for the synthesis of CDs and determination of riboflavin.

Development of nitrogen and sulfur-doped carbon dots for cellular imaging / 药物分析学报

Heteroatom-doped carbon dots (CDs) have attracted extensive interest because of their improved elec-tronic and fluorescence properties with heteroatom doping. In this study, a new synthetic method for nitrogen (N) and sulfur (S) -doped CDs was developed via a hydrothermal method using methionine and citric acid as raw materials. The as-prepared CDs exhibit excellent optical properties and good bio-compatibility. The spherical N,S-doped CDs have an average diameter of 5 nm. They consist of C, O, N and S, and take on excellent water solubility due to the hydroxyl and carboxyl, amino groups on the surface. The CDs have a photoluminescence quantum yield of 13.8％ using quinine sulfate as a reference; the average fluorescence lifetime of the CDs was 3.67 ns. The CDs solution present good photoluminescence properties, and the maximum excitation wavelength and emission wavelength locate at 330 nm and 405 nm, respectively. In addition, their fluorescence intensity almost does not change under the condi-tions of acid, alkali, and high salt, which indicated their anti-photobleaching property and good light stability. Based on the good biocompatibility and strong fluorescence emission of the CDs, they can be used as fluorescent imaging reagents.

Effects of zinc gluconate carbon dots in cell imaging and inducing osteoblastic differentiation in vitro / 吉林大学学报(医学版)

Objective: To synthesize the zinc gluconate carbon dots (Zn-CDs) by one-step hydrothermal method, and to investigate their effects on the cell imaging and inducing osteoblastic differentiation of preosteoblasts in the mice. Methods: The Zn-CDs were synthesized by one-step hydrothermal method, and the characteristics were observed and detected by transmission electron microscope (TEM), Fourier transform-infrared spectrum (FT-IR) and fluorescence spectrometer. The MC3T3-E1 cells were divided into blank control group and experimental groups; different concentrations (0.01, 0.10, 1.00, 10.00, 100.00, 1 000 mg middot; L-1) of Zn-CDs were added into the cells in experimental groups, and nothing was added into the cells in blank control group. MTT assay was used to determin the relative growth rate (RGR) of MC3T3-E1 cells in various groups; the imaging characteristics of MC3T3-E1 cells were observed under confocal microscope; the relative expression levels of Runt-relateed transcription factor-2 (Runx2), alkaline phosphatase (ALP) and osteocalcin (OC) mRNA in the MC3T3-E1 cells in various groups were detected by qRT-PCR; the number of calcified nodules was detected by alizarin red staining. Results: The TEM results showed that the particle size of Zn-CDs was about 5. 25 nm. The fluorescence spectrometer results showed that the Zn-CDs had the fluorescence properties of 360 nm ultraviolet excited light and 450 nm blue emission light, and the Zn-CDs showed the characteristics of excitation wavelength dependence. The FT-IR results showed that the surface of Zn-CDs was mainly composed of carboxyl groups and hydroxyl groups. Compared with blank control group, the RGR of MC3T3-E1 cells in 1 000. 00 mg middot; L-1 Zn-CDs group was decreased significantly at 24 h after co-culture (P<0. 01). The results of fluorescence imaging showed that the blue, green and red fluorescence in the MC3T3-E1 cells, the outline was clear, and the fluorescence intensity of the cytoplasm was stronger than that of the nucleus after co-cultured with Zn-CDs. The qRT-PCR results showed that the relative expression levels of Runx2, ALP and OC mRNA were significantly increased with the increasing of Zn-CDs concentration. The alizarin red staining results showed that the number of calcium deposits in the MC3T3-E1 cells in different concentrations of Zn-CDs groups were more than that in blank control group after induced for 21 d. Conclusion: Zn-CDs can effectively perform the fluorescence imaging in the MC3T3-E1 cells, and Zn-CDs have a certain ability to promote the osteoblastic differentiation of the MC3T3-E1 cells.

Novel carbon dots derived from Dryopteridis Crassirhizomatis Rhizoma Carbonisatum and their hemostatic effect / 中草药

Objective: A new type of nanoparticles-carbon dots was identified from Dryopteridis Crassirhizomatis Rhizoma Carbonisatum (DCC) and investigated their hemostatic effect. Methods DCC was boiled, filtered, and dialyzed to separate and obtain a novel type of carbon dots named DCC-CDs. These DCC-CDs were characterized using transmission electron microscopy (TEM) and high-resolution TEM, as well as Fourier transform infrared, ultraviolet-visible, X-ray photoelectron spectroscopy, and HPLC. Then, the anti-hemorrhagic effects were evaluated by severed tails ad liver bleeding tests and the related hemostatic mechanisms of the obtained DCC-CDs were assessed by detecting blood coagulation and PLT quantity to discuss the hemostasis mechanism. Results The DCC-CDs separated from DCC were spherical, monodisperse, which had a narrow size distribution between 1 and 7 nm. In the animal experiment, DCC-CDs were revealed excellent hemostatic bioactivity, and significant decreased in the tail and liver bleeding time (P < 0.01). Additionally, the rats showed a profound increasing in fibrinogen (FIB) and platelets (PLT) after DCC-CDs treatment (P < 0.05). Conclusion These results demonstrated an explicit hemostatic effect of DCC-CDs, which offers new avenues for research into DCC to treat hemorrhagic diseases and a new mindset for the exploration of the active ingredients of traditional Chinese medicine.

Transmembrane mechanism and intracellular trafficking of folic acid-polyethyleneimine carbon dots / 吉林大学学报(医学版)

Objective: To investigate the transport pathway and intracellular distribution of the of fluorescent carbon dots (CDs) synthesized by folic acid and polyethyleneimine (PEI) through the membrane of MC3T3-E1 cells and its effect on the cells, and to clarify the mechanism. Methods: The fluorescent CDs with the function of cell imaging were synthesized by hydrothermal method using folic acid and PEI as the raw materials; MTT assay was applied to screen the best concentration of CDs. The MC3T3-E1 cells were divided into blank control group, folic acid grodp and CDs grodp. The biocompatibility of CDs was evaldated by the detection of cell cycle, apoptosis and celldlar reactive oxygen species (ROS) level. Nystatin as a kind of caveolae inhibitor and nocodazole as a kind of macropinocytosis inhibitor were dsed to find od the pathway throdgh which the cells took in the CDs. Using the charcteristic of CDs with bld fldorescence stimdlated by dltraviolet ray, the organelle probes were dsed to observe the distribdtion of CDs. Results: Compared with blank control grodp, the cells in different concentrations (100 - 450 mg · L-1) of CDs grodps showed no cytotoxicity at 24 h (P>0.05); at 48 h, the cell proliferation rate was reddced to 68.4% of blank control grodp when the concentration of CDs reached 350 mg · L-1(P0.05). Compared with blank control grodp, the apoptotic rates of the cells in folic acid grodp and CDs grodp had no significant differences (P>0.05). Compared with blank control grodp, the intracelldlar ROS levels in folic acid grodp and CDs grodp were significantly decreased (P<0.05). Compared with blank control grodp, the dptake amodnt of CDs in the cells was decreased in nystatin grodp (P<0.05). The blde fldorescence of CDs overlapped with the red fldorescence of mitochondria dnder an inverted fldorescence microscope, the blde fldorescence of CDs overlapped with the red fldorescence of lysosomes; they didn't overlap completely with the red fldorescence of the endoplasmic reticdldm; the blde fldorescence of CDs overlapped poorly with the red fldorescence of Golgi apparatds. Conclusion: CDs perform well in biocompatibility and they can be distribdted to different organelles after taken in by the cells. They can be dsed as a kind of gene carrier in transgenic therapy.

Fluorescence Carbon Dot-based Imprinted Polymer for Highly Selective Detection of Bovine Hemoglobin / 分析化学

A novel fluorescent imprinted polymer (CDs@ MIP) with selective recognition of hemoglobin was prepared by the sol-gel method using fluorescent carbon dots as the carrier material, 3-aminopropyltrieth-oxysilane as the functional monomer, tetraethoxysilane as the crosslinking agent and bovine hemoglobin as template molecule. The results of IR and scanning electron microscopy showed that the molecularly imprinted polymer was coated on the surface of fluorescent carbon dots. The CDs@ MIP showed selective recognition properties for bovine hemoglobin with an imprinting factor of 4. 60. Also the adsorption ability and specific recognition performance of CDs@ MIP were investigated, and it was found that the CDs@ MIP had high selectivity toward bovine hemoglobin, and the selection factors for ovalbumin, bovine serum albumin and human serum albumin were 4. 38, 4. 73 and 3. 66, respectively. Under the optimal conditions, the linear range of CDs@ MIP for bovine hemoglobin was 0. 1-10. 0 μmol/ L and the detection limit was 23. 0 nmol/ L. The CDs@ MIP was successfully used for the determination of bovine hemoglobin in bovine blood samples with recoveries of 99. 0％ -102. 5％ .

Transmembrane mechanism and intracellular trafficking of folic acid-polyethyleneimine carbon dots / 吉林大学学报(医学版)

Objective:To investigate the transport pathway and intracellular distribution of the of fluorescent carbon dots(CDs)synthesized by folic acid and polyethyleneimine(PEI)through the membrane of MC3T3-E1 cells and its effect on the cells,and to clarify the mechanism.Methods:The fluorescent CDs with the function of cell imaging were synthesized by hydrothermal method using folic acid and PEI as the raw materials;MTT assay was applied to screen the best concentration of CDs.The MC3T3-E1 cells were divided into blank control group,folic acid group and CDs group.The biocompatibility of CDs was evaluated by the detection of cell cycle,apoptosis and cellular reactive oxygen species(ROS)level.Nystatin as a kind of caveolae inhibitor and nocodazole as a kind of macropinocytosis inhibitor were used to find out the pathway through which the cells took in the CDs.Using the charcteristic of CDs with blue fluorescence stimulated by ultraviolet ray,the organelle probes were used to observe the distribution of CDs.Results:Compared with blank control group,the cells in different concentrations(100-450 mg·L-1)of CDs groups showed no cytotoxicity at 24 h(P>0.05);at 48 h,the cell proliferation rate was reduced to 68.4% of blank control group when the concentration of CDs reached 350 mg · L -1(P<0.05). Compared with blank control group,the percentages of cells in G0phase and G1phase in CDs group were decreased (P<0.05),and the percentage of cells in S phase was increased(P<0.05);the percentages of cells in G2phase and M phase were increased,but there no was significant differences(P>0.05).Compared with blank control group,the apoptotic rates of the cells in folic acid group and CDs group had no significant differences(P>0.05). Compared with blank control group,the intracellular ROS levels in folic acid group and CDs group were significantly decreased(P<0.05).Compared with blank control group,the uptake amount of CDs in the cells was decreased in nystatin group(P<0.05).The blue fluorescence of CDs overlapped with the red fluorescence of mitochondria under an inverted fluorescence microscope,the blue fluorescence of CDs overlapped with the red fluorescence of lysosomes;they didn't overlap completely with the red fluorescence of the endoplasmic reticulum;the blue fluorescence of CDs overlapped poorly with the red fluorescence of Golgi apparatus.Conclusion:CDs perform well in biocompatibility and they can be distributed to different organelles after taken in by the cells.They can be used as a kind of gene carrier in transgenic therapy.

Synthesis of high biocompatible nitrogen-doped carbon dots for staining in bio-imaging / 中国药科大学学报

With citric acid as carbon source and different amino acids as nitrogen source,the nitrogen-doped carbon was synthesized by one-step hydrothermal method under the condition of no catalyst.The pre-experiments show that arginine-doped carbon dots(CDs-Arg) with relatively high fluorescence quantum yield (33.25％) were picked out for further study.Furthermore,we studied the physical and chemical properties of CDs-Arg through a series of spectral,electric potential,particle size,X ray and elemental analysis experiments.At the same time,the stabilities of the nanoparticles towards different pH,temperatures,excitation lasers or redox conditions were studied.And the MTr and in vivo distribution experiments were also conducted for the toxicity and metabolism studies.The experimental results showed that the arginine doped carbon dots has high fluorescence efficiency,good stability,and extremely low toxicity.And the water-soluble small particles of CDs-Arg nanoparticles showed that the nanoparticles can be excreted through the glomerulus.These results show that the CDs-Arg Nanoparticles are biocompatible nanoparticles and have potential applications in biological imaging and can serve as a monitor of drug metabolism.

Preparation of Element-doped Fluorescent Carbon Dots and Their Applications in Biological Imaging / 分析化学

Carbon dots have drawn a lot of attentions for their potential usage in bioimaging on the basis of their good biocompatibility and excellent anti-photobleaching ability. However, the relative low fluorescence quantum yield and lockage of near infrared fluorescence emission restrict their applications in the fluorescence imaging analysis. With the improvement of fluorescent properties through different elements doping, more and more carbon dots are used in biological imaging. In this paper, the synthesis of element-doped carbon dots, the influence by different elements doping and the development of element-doped carbon dots in imaging analysis are summarized, and the future prospect are anticipated.

Preparation of Silicon and Boron-doped Carbon Dots and Their Application in Hemoglobin Sensing / 分析化学

Heteroatom doping is an effective way to elevate the fluorescent performance of carbon dots. In this study, a microwave one-pot approach for the synthesis of SiBCDs was proposed by using citric acid ( C6 H8 O7 ) , boric acid ( H3 BO3 ) and (3-aminopropyl) triethoxy sliane ( APTES) as source materials. PAAS-SiBCDs were prepared with the assistance of microwave when sodium polyacrylate ( PAAS) was added in the precursor of SiBCDs. The products were characterized by X-ray diffraction ( XRD ) , X-ray photoelectron spectroscopy ( XPS ) and Fourier transform infrared ( FT-IR ) spectra, respectively, confirming that the product was amorphous CDs, with small amount of Si and B. The synthesized SiBCDs had good monodispersity with size of 4-8 nm, the average size of PAAS-SiBCDs was 5. 2 nm, and the excitation/emission maximum was 350 nm/445 nm. The quantum yield of SiBCDs was 20. 1%, and that of PAAS-SiBCDs was 34. 6%. Based on the quenching effect of hemoglobin ( Hb ) on the fluorescence PAAS-SiBCDs, a sensitive Hb detection method was developed. A linear range of 0. 21-5. 22 μmol/L was obtained together with a detection limit of 0. 06 μmol/L. The method was applied in the determination of Hb in human blood samples.

Preparation of Coal-based C-dots and Their Application in Trace CuⅡ Detection / 分析化学

One of the hot spots of nanomaterials research is the preparation of carbon-dots ( C-dots) by simple steps with cheap raw materials and looking for its potential application. In this study, coal-based C-dots was prepared from coal mined of Wucaiwan in Xinjiang by mixed acids ( H2 SO4+HNO3 )/ultrasound treatment, and at the same time of structural characterization, the coal-based C-dots were used as fluorescent probe to detect metal ions in water. It was found that the coal-based C-dots were polycyclic aromatic hydrocarbons with particle size of (8±4) nm linked with oxygen-containing groups such as nitro group, possessing the annulus wall of multilayer graphene fragment structures built up by sp2 carbons. This endowed the coal-based C-dots with good dispersity in water, high absorbance and strong fluorescence. The coal-based C-dots were used as viable probes in that their fluorescence was selectively quenching by CuⅡ. The finding was exploited to design a fluorometric assay for CuⅡ with a detection limit of 9. 6 nmol/L.

Preparation of Carbon Dots and Their Application in Food Analysis as Signal Probe / 分析化学

As the new popular fluorescent carbon nanomaterials, carbon dots have not only excellent optical properties and small size characteristics, but also have good biocompatibility, low toxicity and easy to achieve the surface functional characteristics, and can replace the traditional semi-quantum dots of the better choice.Based on the unique fluorescence characteristics and high sensitivity, carbon fluorescent probe has a good potential in food analysis and testing. In this experiment, the study of fluorescent carbon dots has been reviewed in recent years. The characteristics of carbon dots are briefly introduced and the preparation methods of carbon dots are summarized. The application of carbon dot fluorescent probes in food analysis and detection is introduced and the limitations and development of carbon point application are analyzed and forecasted.

Preparation of Coal-based C-dots and Their Application in Trace CuⅡ Detection / 分析化学

One of the hot spots of nanomaterials research is the preparation of carbon-dots ( C-dots) by simple steps with cheap raw materials and looking for its potential application. In this study, coal-based C-dots was prepared from coal mined of Wucaiwan in Xinjiang by mixed acids ( H2 SO4+HNO3 )/ultrasound treatment, and at the same time of structural characterization, the coal-based C-dots were used as fluorescent probe to detect metal ions in water. It was found that the coal-based C-dots were polycyclic aromatic hydrocarbons with particle size of (8±4) nm linked with oxygen-containing groups such as nitro group, possessing the annulus wall of multilayer graphene fragment structures built up by sp2 carbons. This endowed the coal-based C-dots with good dispersity in water, high absorbance and strong fluorescence. The coal-based C-dots were used as viable probes in that their fluorescence was selectively quenching by CuⅡ. The finding was exploited to design a fluorometric assay for CuⅡ with a detection limit of 9. 6 nmol/L.

Preparation of Carbon Dots and Their Application in Food Analysis as Signal Probe / 分析化学

As the new popular fluorescent carbon nanomaterials, carbon dots have not only excellent optical properties and small size characteristics, but also have good biocompatibility, low toxicity and easy to achieve the surface functional characteristics, and can replace the traditional semi-quantum dots of the better choice.Based on the unique fluorescence characteristics and high sensitivity, carbon fluorescent probe has a good potential in food analysis and testing. In this experiment, the study of fluorescent carbon dots has been reviewed in recent years. The characteristics of carbon dots are briefly introduced and the preparation methods of carbon dots are summarized. The application of carbon dot fluorescent probes in food analysis and detection is introduced and the limitations and development of carbon point application are analyzed and forecasted.

Preparation and evaluation of fluorescent carbon dots (CDs) and CDs based immunofluorescence probe / 医疗卫生装备

Objective To fabricate an immunofluorescence probe system of carbon dots conjugated antibody based on antigen-antibody reaction principles.Methods A green one-step microwave assisted pyrolysis method was applied to preparing fluorescent carbon dots (CDs) using aminoglucose as carbon source and the obtained CDs were conjugated with antibody via EDC/NHS reactions to build CDs based fluorescent probe.Furthermore,the properties of CDs and CDs based probe system were evaluated by Fourier transform infrared (FTIR) spectra,transmission electron microscopy (TEM),UV-vis absorption and so on.Results The as-prepared CDs showed excellent fluorescence and hydrophilicity and CDs based immunofluorescence probe exhibited the capability of quick detection of E.coli O157:H7.Cinclusion Fluorescent CDs as one new emerging environment-friendly nanomaterial has great potential in biosensors.