Fluorescent probes that distinguish proteins with single or two close mercapto groups

A β-allyl carbamate fluorescent probe for vicinal dithiol proteins

An unprecedented β-allyl carbamate fluorescent probe for vicinal dithiol proteins (VDPs) was developed. The favourable properties of the probe make it a useful tool for tracing the global changes of VDPs in living systems.

A novel algorithm for second-order calibration of three-way data in fluorescence assays of multiple breast cancer-related DNAs

Fluorescent probes have been valuable tools for bioanalytical multiplex assays. However, as a common phenomenon in multiplex fluorescence assays, spectral overlap usually leads to difficulty in spectral analysis for multiple analytes. Although multiway calibrations have provided mathematic approaches for complex spectral analysis, it remains a grand challenge for these methods in practical applications because of the problems such as prior rank estimation. Herein, we report a novel second-order calibration algorithm of alternating residual trilinearization (ART) for the decomposition of complex spectra generated from multiplex fluorescence assays. By alternating iterative convergence to the spectral profiles of each component in convergence process, ART enables automatic rank estimation for second-order calibration, thus able to avoid the risk of chemical meaningless fitting of component spectra. Combined with fluorescence excitation-emission matrix (EEM) spectroscopy, the performance of ART has been demonstrated by a simulated example and an analytical experiment performed using molecular beacons (MBs) for the simultaneous assay of three breast cancer related DNA targets. The results revealed that the proposed algorithm is capable of automatic estimating the number of underlying components during its convergence process to produce acceptable performance in spectral profile resolution and concentration estimation. Compared with other existing iterative trilinear decomposition strategies such as parallel factor analysis (PARAFAC) requiring a prior rank estimation, the proposed ART therefore provides a robust second-order calibration strategy for complex spectral analysis in multiplex fluorescence assays.

Aminomaleimide fluorophores: a simple functional group with bright, solvent dependent emission

Amino-substituted maleimides form a new class of highly emissive compounds, with large Stokes shifts (>100 nm) and high quantum yields (up to ∼60%).

Amino-substituted maleimides form a new class of highly emissive compounds, with large Stokes shifts (>100 nm) and high quantum yields (up to ∼60%). Emission is responsive to the maleimide's environment with both a red-shift, and quenching, observed in protic polar solvents. Aminomaleimides are easily functionalised, providing a versatile fluorescent probe.

Unusual regio- and stereo-selectivity in Diels-Alder reactions between bulky N-phenylmaleimides and anthracene derivatives

Unusual regio- and stereo-selectivity in Diels-Alder (D-A) reactions were achieved between bulky N-phenylmaleimides and anthracene derivatives. Using multiple substituents with steric hindrance on both diene and dienophile, a noticeable shift toward 1,4-addition was successfully obtained. The substrate scope in this reaction was broad and the highest yield of anti-1,4-adducts was over 90%. Novel structures of anti-1,4-adducts were confirmed by single crystal X-ray diffraction analysis. This study not only provides the first reported method of synthesizing anti-1,4-adducts and achieving otherwise unattainable regio- and stereo-selectivity, but also elucidates the importance of combining the steric effects of two reactants to shift products toward 1,4-adducts. Moreover, the resulting 1,4-adducts could be further functionalized through their halogen groups via carbon-carbon coupling reactions.