Selective recognition of adenosine 5＇-triphosphate （ATP） is of great significance owing to its indispensable functions to organisms. Also, it is a challenging task because other nucleosides triphosphate hold the same triphosphate group and structurally planar bases as ATP. It is known that metal-organic frameworks （MOFs） are a new type of sensing material. In this work, highly selective recognition of ATP against other nucleosides triphosphate is successfully achieved with a luminescent MOF of [Zn（BDC）（H2O）2]n （BDC2- = 1,4-benzenedicarboxylate）. [Zn（BDC）（H2O）2]n dispersed in water shows a remarkable redshift of the emission wavelength upon addition of ATP, while cytidine 5＇-triphosphate （CTP）, uridine 5＇-triphosphate （UTP） and guanosine 5＇-triphosphate （GTP）, as well as some inorganic anions such as P2074- or PO43- can＇t induce such spectral change as ATP. 1H NMR, 31p NMR and Raman spectra indicate that both π-π stacking interactions and the coordination of Zn（II） with adenine and the phosphate group are involved in the interaction of [Zn（BDC）（H2O）2],, with ATP. In addition, the experimental results showed that the redshift extent of the emission wavelength of [Zn（BDC）（HzO）2]n has the linear relation- ship with the concentration of ATP in the range of 0.3-1.8 mmol/L. Based on this, the detection of ATP content in the sample of ATP injection was made with satisfactory results. This system pioneers the application of MOFs in the recognition of nucle- otides, and testifies that the participation of base in the recognition process can improve the selectivity against the other nucleotides.
A simple and sensitive method for detection of captopril was established based on its obstructive effect on nanomaterial sur- face energy transfer （NSET）. It was found that the acridine orange （AO） could be adsorbed onto the surface of citrated-gold nanoparticles （AuNPs） through electrostatic interaction. Incidentally, the fluorescence of AO was quenched owing to the dipole-dipole interaction of NSET between AO fluorophore and the AuNPs. However, captopril could obstruct the occurrence of NSET between AO and AuNPs effectively with the formation of Au-S covalent bonds between it and the AuNPs. Consequently, AO molecules were moved away from the surface of AuNPs leading to a decline of the energy transfer efficiency. Moreover, the fluorescence of AO could be gradually restored with the addition of captopril. Under the optimal conditions, the recovered fluorescence intensity correlated linearly with the concentration of captopril in the range of 400 nmol/L-2.0μmol/L with a detection limit of 71 μmol/L. Besides, the proposed method was successfully applied for the detection of captopril in troches with the recovery of 93%-102% and the RSD lower than 2.24%. The results were in good agreement with those obtained from the HPLC method,
Precise control of the size and morphology of metal-organic frameworks(MOFs) presents an important direction for extending these inorganic-organic materials to many more advanced applications. However, because of the limit of the crystal-growth rule and mechanism, good-control of the size and morphology of MOFs remains challenging. In this contribution, an iron-terephthalic acid metal-organic framework with different shapes(octahedron, spindle and bipyramidal hexagonal) was easily and reproducibly synthesized via a solvothermal method. Sodium acetate and glycerol were used as modulators. Mechanism studies showed that the crystal nucleation rate and orientational growth both play important roles in determining the final shape of the MOFs. Further investigations showed that the as prepared MOFs exhibit shape-dependent catalytic activities, which means that MOFs can be designed to perform different catalytic functions. This investigation not only provides an effective guideline for the precise control of the size and morphology of metal-organic frameworks, but also extends MOFs to much more advanced applications in terms of catalyst chemistry.
