Studies of Benzothiazole and Benzoselenazole Squaraines as Fluorescent Probes for Albumins Detection

Series of squaraine benzothiazole and benzoselenazole dyes were studied as possible fluorescent probes for the detection of proteins, particularly albumins. It was shown that majority of the studied squaraines give significant fluorescent response on the human serum albumin (HSA) and bovine serum albumin presence. For squaraine dyes with N-hexyl pendent groups (P-1, P-2, P-3, P-5) about 100−540-fold fluorescence intensity increase upon albumins addition was observed. At the same time in presence of other proteins, namely insulin, avidin from hen egg white, immunoglobulin G (IgG), carbonic anhydrase fluorescence enhancement values were considerably lower —up to 43 times in IgG presence. It was noted that generally, squaraines with long N-hexyl pendent groups demonstrate higher emission increase values upon proteins addition comparing with their analogues with short N-ethyl tails. It was shown that fluorescence intensity enhancement for benzothiazole squaraine dye P-3, relates linearly to the HSA concentration over the wide range—from 0.2 to 500 μg/ml. Together with noticeable selectivity of this dye to albumins, existence of wide dynamic range gives possibility to propose P-3 dye as probe for HSA quantification.     

Investigation of non-adiabatic effects for the ro-vibrational spectrum of H3+: the use of a single potential energy surface with geometry-dependent nuclear masses

ABSTRACT

The influence of non-adiabatic effects on the ro-vibrational bound states of H⁺ ₃ has been investigated using geometry-dependent reduced masses and only one single potential energy surface. The used potentials (BO electronic energy, adiabatic corrections and relativistic contributions) are based on explicitly correlated wavefunctions. For the first time, several different fully geometry-dependent reduced mass surfaces in three dimensions have been incorporated for the vibrational and rotational contributions.