Xin Chen

University of Jinan (Jinan, China), Chi-nan-shih, Shandong Sheng, China

Are you Xin Chen?

Claim your profile

Publications (16)10.63 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: In the present paper, a series of novel conjugated polymers, poly[(silylene)acetylene silanes] with different structure, were prepared, and the luminescence performance of the poly[(silylene)acetylene silanes] with different substituents were investigated by the fluorescence and UV absorption spectroscopic approaches. The effect of different substituents and the number of acetylene in the main chain on the luminescence was discussed in depth. The result showed that these polymers have moderate absorbance in the range from 219 to 260 nm. The red shift was showed for the maximum absorbance wavelength following the increase in the number of the acetylene and the degree of the conjugation in the main chain. There was insignificant difference in the maximum absorbance wavelength of the polymers with dimethy and diphenyl. In short, the influence of the substituents is insignificant. However, the remarkable effect was induced by the conjugated structure in the main chain. The conjugated polymers with different structure in the main chain have moderate fluorescence and emission quantum yields. The authors studied the influence of the polymers' structure on the luminescence performance. As a result, the influence of the substituents is insignificant for emission spectra. The influence of the conjugated groups in the main chain of the polymers is remarkable. The maximum emission wavelength of the polymers showed an evident shift to red range with the enhancement of the conjugated extent. These polymers had good thermal properties for the special structures. So they have potential applications for emission materials with good thermal stability.
    Guang pu xue yu guang pu fen xi = Guang pu 06/2009; 29(6):1665-7. · 0.29 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: In the present paper, the binding reaction between meso-tetra-(4-hydroxyphenyl)-Zn porphyrin (TPP-Zn) and bovine serum albumin (BSA) was studied at different temperatures by fluorescence method. It was shown that meso-tetra-(4-hydroxyphenyl)-Zn porphyrin has a strong ability of quenching the fluorescence of bovine serum albumin. Based on the mechanisms of fluorescence quenching of bovine serum albumin caused by meso-tetra-(4-hydroxyphenyl)-Zn porphyrin, the binding constants between meso-tetra-(4-hydroxyphenyl)-Zn porphyrin and bovine serum albumin were measured under different temperatures. The experiment showed that meso-tetra-(4-hydroxyphenyl)-Zn porphyrin and bovine serum albumin have strong interactions. The binding constants of the reaction at 27 degrees C, 35 degrees C and 42 degrees C were 1.521 x 10(6) L x mol(-1), 7.048 x 10(5) L x mol(-1) and 1.473 x 10(5) L x mol(-1), respectively, and were decreased with increasing the temperature. The constants of maximum diffusion collision quenching rate-K(q) were above 2.0 x 10(10) L x mol(-1) x s(-1). Therefore, the sort of quenching between meso-tetra-(4-hydroxyphenyl)-Zn porphyrin and bovine serum albumin was determined as static quenching. By the theory of Förster of non-radiation energy transfer, the binding distance and the energy transfer efficiency at 27 degrees C between meso-tetra-(4-hydroxyphenyl)-Zn porphyrin (accepter of energy) and bovine serum albumin (donor of energy) were obtained, respectively. The binding distance was 3.72 nm, which is less than 7 nm, therefore, the interaction was similar to the non-radiation energy transfer, and the static quenching was further proved. According to the thermodynamic parameters, the main sorts of binding force between meso-tetra-(4-hydroxyphenyl)-Zn porphyrin and bovine serum albumin could be judged as electrostatic force when deltaG < 0, deltaH < 0 and deltaS > 0.
    Guang pu xue yu guang pu fen xi = Guang pu 04/2009; 29(3):773-6. · 0.29 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The interaction between novel asymmetrical porphyrin 5,10,15-triphenyl-20-pyridyl porphyrin and ascorbic acid has been studied by fluorophotometry. It has been found experimentally that in the presence of CTMAB micro-emulsion, the absorption and fluorescence intensity of the porphyrin was greatly enhanced. The addition of ascorbic acid caused the decrease of the intensity, and there was a linear relationship between the fluorescence quenching value and the concentration of ascorbic acid in certain extent. Based on this phenomenon, a new fluorescence quenching method for the determination of ascorbic acid was established, and utilized in the determination of commercial tablets with satisfactory results. The quenching mechanism between porphyrin and ascorbic acid was preliminary studied, and the quenching was belonging to static quenching.
    Journal of Fluorescence 04/2009; 19(5):809-15. · 1.79 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Interest in the interaction between cationic porphyrins, particularly derivatives of meso-tetra(N-methylpyridinium-4-yl) porphyrin(TMPyP), and DNA abounds because they are versatile DNA-binding agents that could find application in photodynamic therapy, cancer detection, artificial nucleases, virus inhibition and so on. The interaction of two water-soluble cationic porphyrins, meso-tetrakis(4-N, N, N-trimethylanilinium) porphyrin (TMAP) and 5-phenyl-10,15,20-tris[4-(N-methyl) pyridinium]porphyrin (TriMPyP), with calf thymus DNA (ctDNA) was studied by UV-Vis absorption spectroscopy, fluorescence spectroscopy and resonance light scattering technique. TriMPyP forms aggregate in water due to the molecular asymmetry while TMAP exists as monomers. At lower concentrations of ctDNA (R > 1, R = c(TMAP)/c(DNA) base pair), the interaction of TMAP with DNA leads to significant hypochromicity and bathochromic shift of absorption spectra. And the fluorescence of TMAP was quenched while it showed enhanced resonance light scattering signals. But the extent of enhancement of resonance light scattering signals is very small, so the aggregate of TMAP is not very high. These observations indicate the self-stacking of TMAP along the DNA surface. At higher concentrations of ctDNA (R < 1), TMAP association with DNA is via outside binding which is accompanied with hyperchromic effect and fluorescence enhancement while the resonance light scattering signals is reduced. DNA addition decreases the fluorescence intensity of TriMPyP and it shifts the peak to the higher wavelengths (red shift). The interaction with DNA promotes the aggregation of TriMPyP and no simple outside binding is observed even at higher concentrations of ctDNA. The steric effect of molecular distortion constrains the intercalation or further binding to DNA. The effect of ionic strength on the interaction was investigated at two DNA concentrations, 1.2 and 24.0 micromol x L(-1), for TMAP. The Interactions of both porphyrins with DNA show high sensitivity to ionic strength. By addition of NaCl, electrostatic attraction is decreased, resulting in the change of binding mode.
    Guang pu xue yu guang pu fen xi = Guang pu 03/2009; 29(2):423-7. · 0.29 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Experiments indicated that protein can enhance the fluorescence of the 4-chlorosulfo-(2'-hydroxylophenylazo)-rhodanine-Ti(IV) complex [ClSARP-Ti(IV)] in the presence of bis(2-ethylhexyl)sulfosuccinate sodium salt (AOT) microemulsion. Based on this, a sensitive and reproducible fluorometric method for the determination of micro amount protein was developed. The calibration curves of four proteins were given. Under the optimum experimental conditions, the enhanced fluorescence intensity of the system was in proportional to the concentration of protein in the range of 0.1-11 microg mL(-1) for bovine serum albumin (BSA), 1.0-10 microg mL(-1) for human serum albumin (HSA), 1.0-50 microg mL(-1) for ovalbumin (Ova) and 2.5-18 microg mL(-1) for gamma-globulins (gamma-G). Their detection limits were 0.070, 0.071, 0.33 and 0.22 microg mL(-1), respectively. The ClSARP-Ti(IV) complex as a spectral probe can be used to the determination of protein in milk powder and oatmeal yielding with satisfactory results. Therefore, the proposed method is one of the most sensitive methods available. In addition, the interaction mechanism of this system is studied by multi-techniques.
    Spectrochimica Acta Part A Molecular and Biomolecular Spectroscopy 02/2009; 72(5):1047-53. · 1.98 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: A new system for the determination of nucleic acid by rare earth metallic porphyrin of [tetra-(3-methoxy-4-hydroxyphenyl)]-Tb3+ [T(3-MO-4HP)-Tb3+] porphyrin as fluorescence spectral probe has been developed in this paper. Nucleic acid can enhance the fluorescence intensity of the T(3-MO-4HP)-Tb3+ porphyrin in the presence of bis(2-ethylhexyl)sulfosuccinate sodium salt(AOT) micelle. In pH 8.00 Tris-HCl buffer solution, under optimum conditions, the enhanced fluorescence intensity is in proportion to the concentration of nucleic acids in the range of 0.05-3.00 microg mL(-1) for calf thymus DNA (ct DNA) and 0.03-4.80 microg mL(-1) for fish sperm DNA(fs DNA). Their detection limits are 0.03 and 0.01 microg mL(-1), respectively. In addition, the binding interaction mechanism between T(3-MO-4HP)-Tb(3+) porphyrin and ct DNA is also investigated by resonance scattering and fluorescence spectra. The maximum binding number is calculated by molar ratio method. The new system can be used for the determination of nucleic acid in pig liver, yielding satisfactory results.
    Luminescence 02/2009; 24(4):217-23. · 1.27 Impact Factor
  • Journal of Porphyrins and Phthalocyanines - J PORPHYR PHTHALOCYA. 01/2009; 13.
  • Mei Yan, Shuyuan Liu, Xin Chen, Bin Du
    [Show abstract] [Hide abstract]
    ABSTRACT: A highly sensitive and selective spectrophotometric method is proposed for the determination of trace lead in food. The method is based on the reaction of lead(II) with a new analytical reagent trihydroxyphenylfluorone (TH-PF). TH-PF reacts with lead(II) and form a stable 1 : 2 complex at pH 10.40. Its apparent molar absorption coefficient and Sandell's sensitivity at 580 nm are 4.56 times 104 L/mol/cm and 4.54 times 10-3 mug/cm2. Beer's law is obeyed in the range of 0-1.6 mug/mL of lead(II). In addition, the optimal condition for the determination with different microemulsion medium was investigated in detail. Sulphydryl dextrane gel (SDG), in which sulphydryl group has a big share, is a good type metallic ion adsorbent. It presents the advantages of higher adsorption capacity, better reuse ability and higher mechanical stability. Therefore, the coexistent metal ions can be separated effectively and lead can be enriched by SDG, greatly improving the selectivity and sensibility of the system. The method is used to determine trace lead in food with satisfactory results.
    01/2009;
  • [Show abstract] [Hide abstract]
    ABSTRACT: The interaction of a water-soluble cationic porphyrin, meso-tetrakis (4-N,N,N-trimethylanilinium) porphyrin (TMAP), with two proteins, bovine serum albumin (BSA) and human serum albumin (HSA), was studied by UV-vis absorption spectroscopy, fluorescence spectroscopy, fluorescence anisotropy and synchronous fluorescence spectroscopy at neutral aqueous solutions. Free base TMAP bound to proteins as monomers and no aggregation was observed. The binding of TMAP quenched the fluorescence of the protein. On the contrary, the fluorescence of TMAP was enhanced and the fluorescence anisotropy increased due to the binding. The direct static binding mechanism could account for the quenching by TMAP and the binding constants were calculated. TMAP showed a higher quenching efficiency and binding constant of HSA than BSA. The binding of TMAP had no obvious effect on the molecular conformation of the protein. There was only one binding site for TMAP and it was located on the surface of the protein molecule. Electrostatic force played an important role in the binding due to the opposite charges on porphyrin and the proteins.
    Spectrochimica Acta Part A Molecular and Biomolecular Spectroscopy 11/2008; 72(3):465-9. · 1.98 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Studies on the binding mechanism between protein and small molecules could give us lots of useful information. For example, a detailed characterization of drug-protein binding properties was essential for understanding the function of delivery, hence, interest in the mechanism of the interaction between them has attracted much research using different methods. In the present paper, the interaction mechanism between meso-tetra-(3,5-dibromo-4-hydroxyphenyl) porphyrin [T(DBHP)P] and bovine serum albumin (BSA) was investigated using fluorescence method. Based on the mechanisms of fluorescence quenching of BSA caused by T(DBHP)P, the binding constants between T(DBHP)P and BSA were measured at different temperatures. The experiment showed that T(DBHP)P and BSA have strong interactions. The binding constants of the reaction at 27 and 48 degrees C were calculated by fluorescence method, respectively. The binding constants are K = 1.30 x 10(6) L x mol(-1) at 27 degrees C, and K = 6. 32 x 10(5) L x mol(-1) at 48 degrees C. Because the binding constants decreased with increasing the temperature, the sort of quenching between T(DBHP)P and BSA was determined as static quenching. By the theory of Forster non-radiation energy transfer, the binding distance and the energy transfer efficiency at 27 degrees C between T(DBHP)P (accepter of energy) and BSA (donor of energy) were obtained to be 2.39 nm and 0.91, respectively. The binding distance was less than 7 nm, therefore, the interaction was similar to the non-radiation energy transfer, and the static quenching was further proved. According to the thermodynamic parameters, the main sorts of binding force between T(DBHP)P and BSA could be judged as electrostatic force when deltaG <0, deltaH <0 and deltaS >0. Using the synchronous fluorescence spectra, the effect of T(DBHP)P on the conformation of BSA was studied. The results indicated that the conformation of BSA was changed when T(DBHP)P was added, and the hydrophobic properties of the environment of residues in BSA decreased. It was proved that fluorescence quenching of BSA was induced by static quenching and non-radiation energy transfer.
    Guang pu xue yu guang pu fen xi = Guang pu 07/2008; 28(6):1322-6. · 0.29 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: In the present paper, the binding characteristics and spectral behavior of interaction of meso-tetra-(3, 5-dibromo-4-hydroxyphenyl) porphyrin [T(DBHP)P] as a new-style probe with protein were studied by the techniques of spectrophotometry. The experiment showed that Tween-80 microemulsion was efficiently used to enhance the sensibility and stability of the system at pH 4. 17(Britton-Robinson buffer solution). Under optimum conditions, the characteristics of absorption spectral of meso-tetra-(3,5-dibromo-4-hydroxyphenyl) porphyrin-protein were investigated, the maximum absorption was located at 425 nm, and the reducing value of absorbance A was in proportion to the concentration of proteins in the range 0.50-6.00 microg x mL(-1) for bovine serum albumin, 0.05-0.60 microg x mL(-1) for ovalbumin, and the limits of detection were 0.106 microg x mL(-1) for bovine serum albumin and 0.039 microg x mL(-1) for ovalbumin. The experiments indicated that the proposed method featured high sensitivity and good selectivity and stability, and was simple and relatively free from interference of coexistent substances. It has been applied to the determination of protein in milk samples with satisfactory. The recovery for the investigated protein from milk was 99.56%-100.2% and the relative standard deviations were less than 2.2%. The sensitive method for the quantitative determination of proteins was proposed and may be applicable to the determination of ultra amounts of protein in food analysis. The effect of ionic strength on the system was investigated, and the result indicated that the binding force between meso-tetra-(3, 5-dibromo-4-hydroxyphenyl) porphyrin and protein was judged as electrostatic force. The influence of protein denaturation was also studied, under higher temperature the structure of protein was destroyed, and thermodynamic movement of the molecular of protein was intensified as the heating time extended.
    Guang pu xue yu guang pu fen xi = Guang pu 06/2008; 28(5):1149-52. · 0.29 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: A novel method for the determination of proteins was developed, based on the enhancement of fluorescence with 4-chloro-(2'-hydroxylophenylazo)rhodanine-Ti(IV) [ClHARP-Ti(IV)] complex as a fluorescence probe. The excitation and emission wavelengths of the system were 335 nm and 376 nm, respectively. The presence of bis(2-ethylhexyl)sulphosuccinate sodium salt (AOT) microemulsion greatly increased the sensitivity of the system. Under optimal conditions, four kinds of proteins, including bovine serum albumin (BSA), human serum albumin (HSA), egg albumin (Ova), and gamma-globin (gamma-G) were studied. The detection limits were 0.182 microg/mL for BSA, 0.0788 microg/mL for HSA, 0.216 microg/mL for Ova and 0.484 microg/mL for gamma-G. The linear ranges of the calibration were 0-12.0, 0-10.0, 0-18.0 and 0-18.0 microg/mL, respectively. The method possessed high sensitivity, good selectivity and was applied to the analysis of protein in milk powder and cornmeal with satisfactory results.
    Luminescence 01/2008; 23(5):333-7. · 1.27 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Porphyrin and metalloporphyrin distribute widely in nature and they play an important role in the life. Synthesis of porphyrin compounds with special function has been the focus of attention. In the present paper, porphyrin and metalloporphyrin compound were synthesized by the following method: by one-step synthesis, tetra-(dimethylaminophenyl) porphyrin (T(DMAP) P) was synthesized with propionic acid, acetic acid and nitrobenzene as solvent and 4-dimethylaminobenzaldehyde and pyrrole as raw material. The yield was 24.24%. The complexes of T(DMAP)P with Zn2+, Mn2+ and Tb3+ were synthesized by solvent of chloroform-N, N dimethylformamide (1 : 1). The effects of solvent, temperature and reaction time on the reaction were discussed. Optimum proportion between porphyrin and metallic salts was studied also and the molar ratios of T(DMAP)P to Zn (CH3COO)2 x 2H2O, T(DMAP)P to MnCl2 x 4H2O, and T(DMAP)P to TbCl3 were 1 : 1.2, 1 : 1.4, 1 : 1.5, respectively. The synthesis of metalloporphyrins under mild conditions is simper with high yield (94.2%, 91.7% and 90.5% for T(DMAP) P combined with Zn2+ , Mn2+ and Tb3+ respectively) and the unstability of metalloporphyrin could be avoided. The constitution and structures of these compounds were studied by elemental analyses, infrared spectrum (IR), and ultraviolet-visible spectrum (UV-Vis). The conductivity of porphyrin compound with different concentration and temperature was studied. It was found that the molar conductivity of T(DMAP)P-TbCl(74.6 s x cm(-2) mol(-1)) was greater than that of T(DMAP)P-Zn (8. 8 s x cm(-2) x mol(-1)) and T(DMAP)P-Mn (25.8 s X cm(-2) mol(-1)). So T(DMAP) P-TbCl could be regarded as the 1 : 1 electrolyte compound while T(DMAP)P-Zn and T(DMAP)P-Mn were non-electrolyte compounds. The influences of different metal ions on the reaction were investigated. The discussion was concentrated on the molecular spectra of porphyrin and metalloporphyrin. Compared with tetraphenyl porphyrin, the absorption of T(DMAP) P and its metal complexes had red-shifts due to the substituent groups and metal ions. When the porphyrin rings were occupied by metal ions, the number of Q band decreased and the absorption peak intensity decreased. Among these metalloporphyrin compounds, the maximum absorption of T(DMAP)P-TbCl had the biggest red-shifts and could be used as ideal photosensitizer.
    Guang pu xue yu guang pu fen xi = Guang pu 01/2008; 27(12):2566-9. · 0.29 Impact Factor
  • Journal of Porphyrins and Phthalocyanines - J PORPHYR PHTHALOCYA. 01/2008; 12(02).
  • [Show abstract] [Hide abstract]
    ABSTRACT: The binding characteristics of meso-tetra-(3, 5-dibromo-4-hydroxphenyl) porphyrin [T(DBHP)P] with calf thymus DNA (ct DNA) in pH 4.92 HAc-NaAc buffer solution were studied by the techniques of spectrophotometry. At the maxium absorption wavelength for T(DBHP)P, the decrease in the absorbance was linear with the amount of ct DNA. The experiments indicated that under optimum conditions, ct DNA obeys Beer's law in the range of 0.20-1.80 microg x mL(-1), and the limit of detection is 0.024 microg x mL(-1). Tween-80 microemulsion was commended in the experiment for better sensitivity. Furthermore, the association number is also determined by molar ratio method. The interactional mechanism between ct DNA and (T(DBHP)P was investigated as well.
    Guang pu xue yu guang pu fen xi = Guang pu 06/2007; 27(5):969-72. · 0.29 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The mechanism of interaction between bovine serum albumin (BSA) and trihydroxylphenylfluorone (TH-PF)-Mo(VI) complex in neutral solution was studied by fluorimetric method. The mechanism of fluorescence quenching of BSA caused by (TH-PF)-Mo(VI) complex probe was investigated and the binding constants under different temperature were measured. The binding constants of the reaction at 25 degrees C and 40 degrees C were calculated by fluorimetric method to be 4.78 x 10(4) L x mol(-1) and 3.72 x 10(4) L x mol(-1), respectively. According to the theory of Forster non-radiation energy transfer, the binding distance and transfer efficiency at 25 degrees C were calculated to be 2.89 nm and 0.314, respectively. Furthermore, the thermodynamic parameters were measured and the results indicated that electrostatic force played a major role in the interaction between TH-PF-Mo(VI) complex and BSA.
    Guang pu xue yu guang pu fen xi = Guang pu 11/2006; 26(10):1899-902. · 0.29 Impact Factor

Publication Stats

15 Citations
10.63 Total Impact Points

Institutions

  • 2007–2009
    • University of Jinan (Jinan, China)
      Chi-nan-shih, Shandong Sheng, China
  • 2006
    • Henan Institute of Science and Technology
      Honanfu, Henan Sheng, China