scholarly journals Effect of Serum Albumin on Porphyrin-Quantum Dot Complex Formation and Characteristics. Spectroscopic Analysis

Nanomaterials ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1674
Author(s):  
André L. S. Pavanelli ◽  
Leandro N. C. Máximo ◽  
Roberto S. da Silva ◽  
Iouri E. Borissevitch
Keyword(s):  
Steady State ◽  
Bovine Serum Albumin ◽  
Complex Formation ◽  
Optical Absorption ◽  
Serum Albumin ◽  
Spectroscopic Analysis ◽  
Complex Form ◽  
Water Soluble ◽  
Time Resolved ◽  
Positively Charged

The effect of bovine serum albumin (BSA) upon interaction between CdTe QD functionalized by 3-Mercaptopropionic Acid (CdTe-3-MPA QD) and two water soluble porphyrins: positively charged meso-tetra methyl pyridyl porphyrin (TMPyP) and negatively charged meso-tetrakis(p-sulfonato-phenyl) porphyrin (TPPS4), was studied in function of pH using the steady-state and time resolved optical absorption and fluorescence spectroscopies. It was shown that, depending on the charge state of the components, interaction with albumin could either prevent the formation of the QD…PPh complex, form a mixed QD…PPh…BSA complex or not affect PPh complexation with QD at all. The obtained results may be of interest for application in photomedicine.

Time-Resolved Fluorescence of Water-Soluble Pyridinium Salt: Sensitive Detection of the Conformational Changes of Bovine Serum Albumin

2016 ◽  
Vol 70 (10) ◽  
pp. 1733-1738 ◽  
Author(s):  
Lei Li ◽  
Hua Yi ◽  
Menghui Jia ◽  
Mengfang Chang ◽  
Zhongneng Zhou ◽  
...  
Keyword(s):  
Bovine Serum Albumin ◽  
Serum Albumin ◽  
Fluorescent Probe ◽  
Conformational Changes ◽  
Fluorescence Lifetime ◽  
Bovine Serum ◽  
Pyridinium Salt ◽  
Water Soluble ◽  
Time Resolved Fluorescence ◽  
Time Resolved

In this paper, we report a pyridinium salt “turn-on” fluorescent probe, 4-[2-(4-Dimethylamino-phenyl)-vinyl]-1-methylpyridinium iodide (p-DASPMI), and applied its time-resolved fluorescence (TRF) to monitor the protein conformational changes. Both the fluorescence lifetime and quantum yield (QY) of p-DASPMI were increased about two orders of magnitude after binding to the protein bovine serum albumin (BSA). The free p-DASPMI in solution presents an ultrashort fluorescence lifetime (12.4 ps), thus it does not interfere the detection of bound p-DASPMI which has nanosecond fluorescence lifetime. Decay-associated spectra (DAS) show that p-DASPMI molecules bind to subdomains IIA and IIIA of BSA. The TRF decay profiles of p-DASPMI can be described by the multi-exponential decay function ([Formula: see text]), and the obtained parameters, such as lifetimes ([Formula: see text]), fractional amplitudes ([Formula: see text]), and fractional intensities ([Formula: see text]), may be used to deduce the conformational changes of BSA. The pH and Cu2+ induced conformational changes of BSA were investigated through the TRF of p-DASPMI. The results show that the p-DASPMI is a candidate fluorescent probe in studying the conformational changes of proteins through TRF spectroscopy and microscopy in the visible range.

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