Search

[Display omitted] • A novel yellow emission Y-CDs were prepared by a hydrothermal method using DHTA. • The Y-CDs as a sensitive sensor could detect Fe3+ and biothiols by dual signals. • This sensor was utilized to sense biothiols in actual samples and living cells. • The Y-CDs were applied for message encryption as solid sensor to detect analytes. The different levels of biothiols in cells can not only screen cancer cells but also play a selective role in killing cancer cells. Therefore, accurate monitoring of biothiol in cancer cells is of great research significance. Herein, novel yellow emission CDs (Y-CDs) were prepared by a simple hydrothermal method using 2, 5-dihydroxyterephthalic acid (DHTA) as precursors. The Y-CDs as a highly efficient dual-mode sensor could detect Fe3+ and biothiols by colorimetric and fluorescence signals. Especially, with the addition of L-Cysteine, the quenched fluorescence could be quickly restored within 2 min and the detection limit was as low as 31.65 nM. Additionally, this sensor was utilized to sense biothiols in actual samples and living cells due to its eminent biocompatibility. Finally, the Y-CDs were successfully applied not only as fluorescent ink for message encryption but also as a portable solid hydrogels sensor for the detection of Fe3+ and biothiols. Therefore, these results suggested that Y-CDs could serve as a promising sensor for Fe3+ and biothiol detection in early cancer screening. [ABSTRACT FROM AUTHOR]

One-pot synthesis of N -CDs was applied as a highly efficient "ON-OFF-ON" fluorescent probe for the rapid detection of CAL and l -Arg/ l -Lys in living cells. As a consequence, these N -CDs as a powerful analysis tool displayed more prominent and influential ability in real-time monitoring CAL and l -Arg/ l -Lys, and might offer a new opportunity for exploring the physiological and pathological processes of amino acid metabolism diseases. [Display omitted] • The nitrogen-doped carbon dots (N -CDs) were synthesized via a simple one-step hydrothermal method. • These CDs could rapidly and selectively detect CAL and l -Arg/ l -Lys with the detection limits as low as 58 nM, 18 nM/16 nM, respectively. • The N -CDs as a fluorescent probe displayed low toxicity and were suitable for sensing CAL and l -Arg/ l -Lys in living cells. The disorder of amino acid metabolism and the abuse of small molecule drugs pose serious threats to public health. However, due to the limitations of existing detection technologies in sensing cinnamaldehyde (CAL) and l -Arginine/ l -Lysine (l -Arg/ l -Lys), there is an urgent need to develop new sensing strategies to meet the severe challenges currently facing. Herein, nitrogen-doped carbon dots (N -CDs) were developed using a simple one-pot hydrothermal carbonization method. These N -CDs exhibited numerous distinctive characteristics such as excellent photoluminescence, high water dispersibility, favorable biocompatibility, and superior chemical inertness. Strikingly, the as-prepared CDs as a highly efficient fluorescent probe possessed significant sensitivity and selectivity toward CAL and l -Arg/ l -Lys over other analytes with a low detection limit of 58 nM and 16 nM/18 nM, respectively. The fluorescence of N -CDs could be quenched by CAL through an electron transfer process. Then, the strong electrostatic interaction between l -Arg/ l -Lys and N -CDs induced the efficient fluorescence recovery. More importantly, the outstanding biosafety and excellent analyte-responsive fluorescence characteristics of N -CDs have also been verified in living cells as well as in serum and urine. Overall, the N -CDs had a wide application prospect in the diagnosis of amino acid metabolic diseases and small molecule drug sensing. [ABSTRACT FROM AUTHOR]

One-pot synthesis of N -CDs was applied as a highly efficient "ON-OFF-ON" fluorescent probe for the rapid detection of CAL and l -Arg/ l -Lys in living cells. As a consequence, these N -CDs as a powerful analysis tool displayed more prominent and influential ability in real-time monitoring CAL and l -Arg/ l -Lys, and might offer a new opportunity for exploring the physiological and pathological processes of amino acid metabolism diseases. [Display omitted] • The nitrogen-doped carbon dots (N -CDs) were synthesized via a simple one-step hydrothermal method. • These CDs could rapidly and selectively detect CAL and l -Arg/ l -Lys with the detection limits as low as 58 nM, 18 nM/16 nM, respectively. • The N -CDs as a fluorescent probe displayed low toxicity and were suitable for sensing CAL and l -Arg/ l -Lys in living cells. The disorder of amino acid metabolism and the abuse of small molecule drugs pose serious threats to public health. However, due to the limitations of existing detection technologies in sensing cinnamaldehyde (CAL) and l -Arginine/ l -Lysine (l -Arg/ l -Lys), there is an urgent need to develop new sensing strategies to meet the severe challenges currently facing. Herein, nitrogen-doped carbon dots (N -CDs) were developed using a simple one-pot hydrothermal carbonization method. These N -CDs exhibited numerous distinctive characteristics such as excellent photoluminescence, high water dispersibility, favorable biocompatibility, and superior chemical inertness. Strikingly, the as-prepared CDs as a highly efficient fluorescent probe possessed significant sensitivity and selectivity toward CAL and l -Arg/ l -Lys over other analytes with a low detection limit of 58 nM and 16 nM/18 nM, respectively. The fluorescence of N -CDs could be quenched by CAL through an electron transfer process. Then, the strong electrostatic interaction between l -Arg/ l -Lys and N -CDs induced the efficient fluorescence recovery. More importantly, the outstanding biosafety and excellent analyte-responsive fluorescence characteristics of N -CDs have also been verified in living cells as well as in serum and urine. Overall, the N -CDs had a wide application prospect in the diagnosis of amino acid metabolic diseases and small molecule drug sensing. [ABSTRACT FROM AUTHOR]

Scheme 1 The luminescence mechanism of the red-emitting CDs and R-CDs as a highly efficient "on–off" fluorescent probe for the detection of Cr 2 O 7 2- and imaging in the living-cells. [Display omitted] • N/S-doped red emitting carbon dots (R-CDs) were prepared by a convenient one-step solvothermal method using o-PDA and p-ABSA as precursors. • These R-CDs could be used for the selective and sensitive detection of Cr 2 O 7 2- with excellent detection limit (80 nM). • The R-CDs possessed low cytotoxicity and had been successfully applied to cell imaging. Cr(VI) as a toxic heavy metal ion can easily enter into the body through drinking or eating and cause liver and kidney diseases as well as cancer. Considering its high biological toxicity and adverse effects on human body, it is desirable to develop a probe to monitor its level in the environment. Herein, a high-efficiency fluorescent nanoprobe based on red emissive carbon dots (R-CDs) was established through a convenient solvothermal strategy. The as-prepared CDs with excitation-independency had the fixed emission wavelength at 627 nm when the excitation wavelength was 560 nm. Further study manifested that the new surface state formed by nitrogen and sulfur doping and the increased conjugated system established through dehydration and carbonization were the main reasons for the fluorescence redshift. In this system, these R-CDs as a fluorescent probe exhibited high specificity and sensitivity to Cr 2 O 7 2- with the linear range of 4–40 μΜ and the limit of detection could reach 80.00 nM. The quenching of these CDs by Cr 2 O 7 2- was efficiently induced through a static quenching process. Meanwhile, the obtained CDs could enter into HeLa cells through endocytosis and exhibit bright red fluorescence in cells under a confocal laser scanning microscope. Thus, this work provided a promising probe not only for detecting Cr(VI) in natural environment but also for imaging in cells. [ABSTRACT FROM AUTHOR]

A sensitive blue fluorescent probe based on carbon dots has been synthesized by a one-pot hydrothermal method for the rapid detection of FA. [Display omitted] • A facile one-step hydrothermal synthesis of N-doped carbon dots (N-CDs) for FA detection using salicylic acid as a precursor was proposed. • N-CDs was used for selective and sensitive detection of FA with excellent detection limits (28 nM). • The fluorescence quenching of N-CDs caused by FA could be attributed to the synergy of static quenching mechanism and internal filtering effect (IFE). • N-CDs possessed good biocompatibility and had been successfully applied to cell imaging. The folic acid (FA) level in human body can be used as an indicator for body's normal physiological activities and offer insight into the growth and reproduction of the body's cells. But the abnormal level of FA can cause some diseases. Herein, we designed a simple and convenient approach to prepare fluorescent N-doped carbon dots (N-CDs) for the FA detection. These N-CDs have excellent hydrophilicity, high photostability, and outstanding biocompatibility, as well as excitation-independent emission behavior with typical excitation/emission peaks at 295 nm/412 nm. Upon the existence of FA, the fluorescence emission spectrum of N-CDs was significantly quenched through the synergy of static quenching mechanism and internal filtering effect (IFE). Under optimal conditions, the limit of detection was 28.0 nM (S/N = 3) within the FA concentration range of 0–200.0 μM. In addition, N-CDs were successfully employed to detect FA in real samples such as urine and fetal bovine serum (FBS), with a recovery rate of 99.6%-100.7% for quantitative addition. Furthermore, cell experiments confirmed the low toxicity and the cell imaging performance of these N-CDs, indicating that the obtained N-CDs could be served as a credible quantitative probe for FA analysis in the field of biosensing. [ABSTRACT FROM AUTHOR]