Spectroscopic studies on interaction and sonodynamic damage of metallochlorophyllin (Chl-M (M=Fe, Zn and Cu)) to protein under ultrasonic irradiation.

In this paper, the chlorophyll derivatives, metallochlorophyllin (Chl-M) (M=Fe, Zn and Cu) including chlorophyllin iron (Chl-Fe), chlorophyllin zinc (Chl-Zn) and chlorophyllin copper (Chl-Cu), were adopted as sonosensitizers to combine with ultrasonic irradiation, and the sonodynamic damage of bovine serum albumin (BSA) was investigated. At first, the interaction of Chl-M with BSA was studied by fluorescence spectroscopy. The results show that the quenching mechanism belongs to a static process and among them the affinity of Chl-Fe to BSA is the most obvious. Then, some influence factors on the sonodynamic damage of BSA molecules in the presence of Chl-M under ultrasonic irradiation were also studied. Synchronous fluorescence spectra show that the binding and damage sites of Chl-M to BSA molecule are mainly on the tryptophan (Trp) residues. The generation of ROS in Chl-M sonodynamic process is estimated by the method of Oxidation-Extraction Spectrometry (OEP). This paper may offer some valuable references for the study of the sonodynamic activity of Chl-M and the effect of the central metals. Synchronously, it contributes to the application of Chl-M in SDT for tumor treatment.

Immobilized molecular beacons: a new strategy using UV-activated poly(methyl methacrylate) surfaces to provide large fluorescence sensitivities for reporting on molecular association events.

We have designed appropriately prepared solid supports consisting of poly(methyl methacrylate) (PMMA) that provide enhanced performance levels for molecular beacons (MBs) that are used for recognizing and reporting on signature DNA sequences in solution. The attachment of primary amine-containing MBs to the PMMA surface was carried out by UV activating the PMMA to produce surface-confined carboxylate groups, which could then be readily coupled to the MBs using 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDC) chemistry. The fluorescence properties of the MBs covalently attached onto this UV-activated PMMA surface were evaluated and compared with the same MBs immobilized onto glass supports. We observed improved limits of detection for the solution complement to the MBs when immobilized onto PMMA, and this was attributed to both the lower autofluorescence levels exhibited by PMMA at the detection wavelengths used and the improved quenching efficiency of the MBs when in their closed hairpin configuration when strapped to a PMMA surface as opposed to glass. As an example of the utility of the PMMA-based immobilization strategies developed for MBs, we report on the analysis of complementary DNAs specific for fruitless (fru) and Ods-site homeobox (OdsH) genes extracted from Drosophila melanogaster fruit flies. The fru gene functions in the central nervous system, where it is necessary for sex determination and male courtship behavior, whereas the OdsH gene is involved in the regulation of transcription.