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Abstract: This paper is trying to research the developing status of carbon dots (CDs), and the results show that the simple, rapid and high yield synthetic methods for CDs and the application of CDs in biological science and analysis field will certainly become an inevitable development trend in the future. The CDs obtained by microwave possess excellent optical properties including UV–Vis absorption, fluorescence and room temperature phosphorescence. Under the conditions of 30°C and 10min, the fluorescence signal (F) of CDs not only could be enhanced by hexadecyltrimethylammonium bromide (CTAB), Triton X-100, Na2S, Na2C2O4 and NH3.H2O, but also could be quenched by sodium dodecyl sulfate, KBrO3, K2S2O8, NaIO4, ascorbic acid, NaBH4, HNO3, HCl, H2SO4, CH3COOH and most metal ions, with the blue or red shifting in varying degrees, indicating the potential values of CDs in analytical application. Besides, the sensitive response of F to pH showed the promise of developing a new pH sensor with CDs. [Copyright &y& Elsevier]

Abstract: Al3+ could react with quercetin (Q) to form [AlQ]3+ complex which could be used as a template for the preparation of poly (vinyl alcohol)–[AlQ]3+ complex imprinting (PVA-C-I). The [AlQ]3+ not only had good matching ability and selectivity with the cavity of PVA-C-I, but also could react with the fluorescein isothiocyanate anion (FITC−) on the outside of cavity by electrostatic interaction to form ion-association complex [AlQ]3+·[(FITC)−]3. The ion-association complex could emit strong and stable room temperature phosphorescence (RTP) on polyamide membrane (PAM) and the ΔI p of the system had linear relationship with the content of Q, showing the highly selective identification of PVA-C-I to Q. Thus, a new coupling technique for the determination of trace Q based on solid substrate room temperature phosphorimetry and poly (vinyl alcohol) complex imprinting (PVA-C-I-SSRTP) was established. The linear range and limit of detection (LOD) of this method were 0.010–2.0 (×10−12 gmL−1) and 2.0×10−14 gmL−1, respectively, showing wide linear range and high sensitivity of PVA-C-I-SSRTP. This method was used to determine the content of Q in waste water, and the results are consistent with those by spectrofluorimetry. Meanwhile, the mechanism for the determination of Q using PVA-C-I-SSRTP was also discussed. [Copyright &y& Elsevier]

The labelling reagent CdSe@CdS-QDs-Cys (QDs-Cys) with the grain diameter of 4.5 nm was synthesized by modifying CdSe@CdS quantum dots (QDs) with cysteine (Cys). At the same time, QDs-Cys-Ab, a phosphorescent quantum dot probe, was developed based on the labelling reaction between -COOH of QDs-Cys and -NH of goat anti human IgE antibody (Ab). This probe with excellent biocompatibility and high specificity could not only emit strong and stable room temperature phosphorescence (RTP), but also could carry out specific immunoassay (IA) with immunoglobulin E (IgE), causing the RTP of the system to sharply enhance. Thus, a new solid substrate room temperature phosphorescence immunoassay (SSRTPIA) for the determination of IgE was established. The limit of quantification (LOQ) of the method was 0.12 fg spot, corresponding concentration was 3.0 × 10 g mL and sampling quantity was 0.40 μL spot. This highly selective, sensitive and accurate SSRTPIA has been applied to determine IgE in biological samples and diagnose diseases, and the results agreed well with those obtained by enzyme-link immunoassay (ELISA). Meanwhile, the mechanisms of QDs-Cys labelling Ab and the determination of IgE by SSRTPIA were also discussed. [ABSTRACT FROM AUTHOR]

Abstract: Calcein (R) could not only emit strong and stable room temperature phosphorescence (RTP) on filter paper using I− as perturber, but also could be oxidized by H2O2 to form a non-phosphorescence compound (R′), resulting in the quenching of RTP signal of R. Moreover, the ortho-hydrogen of phenolic hydroxyl in R took condensation reaction with rhamnose (Rha) to produce non-phosphorescence compound (R–Rha) causing the RTP signal of R to further quench, and R–Rha was oxidized by H2O2 to form R′ and Rha, bringing about the sharp RTP signal quenching of R. Thus, a new solid substrate room temperature phosphorimetry (SSRTP) for the determination of trace Rha based on its strong catalytic effect on H2O2 oxidizing R has been established, with the detection limit (LD) of 7.8zgspot−1 (corresponding concentration: 2.0×10−17 gml−1, sample volume: 0.40μlspot−1). This method has been applied to determine trace Rha in cigarettes and jujubes, with the results coinciding well with those determined by a high performance liquid chromatography (HPLC). The component of R–Rha also was analyzed by means of HPLC, mass spectrometer and nuclear magnetic resonance (NMR) measurements. The mechanism of catalytic SSRTP for the determination of trace Rha was discussed. [Copyright &y& Elsevier]

Multi-wall carbon nanotubes (MWNTs) could be modified as water soluble MWNTs (it was called as MWNTs-A and MWNTs-B) by chemical methods. MWNTs-A and MWNTs-B could emit room temperature phosphorescence (RTP) signal on the surface of nitrocellulose membrane (NCM). A new solid substrate-room temperature phosphorimetry (SS-RTP) for the determination of trace alkaline phosphatase (ALP) was established based on the signal magnification effect of tween-80 and ALP on MWNTs-B’s RTP intensity and the linear relationship between the content of ALP and the Δ IP of the system. The linear range of this method was 0.0020–0.80 (fg spot−1, sample volume: 0.40 μl spot−1), the regression equation of working curve was $$ \Delta {I_P} = 0.8170 + 96.84{m_{ALP}}\left( {fg{ }spo{t^{ - 1}}} \right) $$, correlation coefficient ( r) was 0.9986. This method had high sensitivity (detection limit (LD): 1.4 ag spot−1), good selectivity (Er ≤ ± 5c/o, coexistence species were of no interference), high precision (RSDs were 4.4%-1.2%) and accuracy. It was applied to the determination of trace ALP in human serum and the diagnosis of human diseases. The results were tallied with those of enzyme-linked immunosorbent assay (ELISA). The mechanism of new SS-RTP for the determination of trace ALP was discussed, which laid the theory foundation for the analytical application of MWNTs in life science. [ABSTRACT FROM AUTHOR]

Polyamide membrane-wheat germ agglutinin-poly vinyl alcohol-affinity adsorption imprinting (abbreviated to PAM-WGA-PVA-AAI) was prepared using alkaline phosphatase (AP) as the template. The cavity in PAM-WGA-PVA-AAI not only matched with AP very well, but also had a sensitive response to AP. The Morin-SiO2-AbAP was obtained using Morin-SiO2 to label AbAP (goat anti human AP antibody). When AbAP-Morin-SiO2 was added to PAM-WGA-PVA-AAI, PAM-AP-AbAP-Morin-SiO2 formed by the immunoreaction between AbAP and AP in PAM-WGA-PVA-AAI due to the affinity between AbAP and AP was stronger than that between AP and WGA. The product could emit room temperature phosphorescence (RTP) because of the heavy atom effect of Pb2+. Motivated by the sensitive response of cavity in PAM-WGA-PVA-AAI to AP, a new PAM-WGA-PVA-AAI phosphorescence sensor for determination of trace AP and prediction of human diseases has been developed using PAM-WGA-PVA-AAI technique. The proposed sensor was sensitive (the detection limit (DL): 0.18agspot−1, corresponding concentration: 7.2×10−17 gmL−1 or 7.2×10−19 molL−1), simple, rapid and highly selective, and it has been applied to the determination of trace AP in human serum and the forecast of human diseases, with the results agreeing well with those obtained by enzyme-linked immunoassay (ELISA). Meanwhile, the mechanism of this PAM-WGA-PVA-AAI phosphorescence sensor was discussed also. [ABSTRACT FROM AUTHOR]

Abstract: Taking advantage of the cutting effect of the strong oxidation of benzoyl peroxide [(C6H5CO)2O2] on the end of multiwall carbon nanotubes (MWNTs) to obtain water-soluble multiwall nanotubes (MWNTs’) and the spiking effect of polyacrylamide (PA) on the room temperature phosphorescence (RTP) of MWNTs’, a new phosphorescent labeling reagent, MWNTs’–PA, has been developed in this study. The product β-AbHCG–MWNTs’–PA obtained by MWNTs’–PA labeling human chorionic gonadotropin-β-subunit three-dimensional core monoclonal antibody (β-AbHCG) not only could maintain good RTP characteristics of MWNTs’ but also could take specific immunoreaction with β-HCG to form β-HCG– β-AbHCG–MWNTs’–PA, resulting in the increase of MWNTs’ RTP signal. Thus, a new solid substrate room temperature phosphorescence immunoassay (SSRTPIA) for the determination of β-HCG has been established. The limits of detection (LODs) of the new method were 0.021pgspot−1 for the direct way at 447/615nm () and 0.016pgspot−1 for the sandwich way at 447/614nm (). This sensitive, accurate, and precise method was used to determine β-HCG and diagnose human diseases by the direct way or the sandwich way, with the results coinciding with those obtained by chemiluminescence immunoassay. Meanwhile, the mechanisms of MWNTs’ labeling β-AbHCG and determining β-HCG are also discussed. [Copyright &y& Elsevier]

Abstract: A new phosphorescence-labelling reagent (3.5-G-D–P labelling reagent) was developed, based on 3.5-generation polyamidoamine dendrimers (3.5-G-D) as internal acceptor to capture porphyrin (P) molecular. In the disturber of heavy atom, 3.5-G-D–P could emit room temperature phosphorescence (RTP) of 3.5-G-D and P on the surface of polyamide membrane (PAM), respectively. Products (3.5-G-D–P–WGA) of 3.5-G-D–P labelling triticum vulgaris lectin (WGA) could emit strong and stable RTP signal on the surface of PAM, and it also could take specific affinity adsorption reaction (AA) with alkaline phosphatase (ALP). The product of the AA reaction (3.5-G-D–P–WGA–ALP) could keep the RTP characteristics of 3.5-G-D–P very well, and the ΔI p of the system was linear correlation to the content of ALP. The ΔI p of the system with Tween-80 was once for P and twice for 3.5-G-D more than that without Tween-80. Thus, the affinity adsorption solid substrate-room temperature phosphorimetry (AA-SS-RTP) for the determination of trace ALP has been established using Tween-80–3.5-G-D–P to label WGA. The detection limit (LD) of this method was 0.12fgspot−1 for 3.5-G-D and 0.18fgspot−1 for P with direct method, 0.14fgspot−1 for 3.5-G-D and 0.17fgspot−1 for P with sandwich method, respectively, and the sensitivity was obviously high. This research showed that either using 3.5-G-D or P excitation/emission wavelength to determine the content of ALP in human serum, the results were coincided with ELISA, and the flexibility of AA-SS-RTP was obviously improved and the applicability was wider. Meanwhile, the reaction mechanism of determining ALP by direct method AA-SS-RTP was discussed. [Copyright &y& Elsevier]