Chengying Hai,Wanjun Long,Yixin Suo,Huanhuan Lu,Hengye Chen,Xiaolong Yang,Jian Yang,Haiyan Fu
Dendrobium huoshanense (DHS) is an expensive Chinese herb with medicinal and edible functions. The quality of DHS is closely related to cultivation methods and years. In this work, nano-effect near and mid infrared spectra of 320 DHS samples with four cultivation methods and four years were obtained, and the feature vectors were obtained using a mid-level data fusion strategy with significant variable extraction and integration using variable importance for the projection (VIP). The feature vectors then combined with partial least squares discriminant analysis (PLS-DA) and orthogonal partial least squares discriminant analysis (OPLS-DA) to identify the cultivation years and methods. The result showed that it is difficult to discriminate effectively by a single spectrum, and the accuracy of PLS-DA discrimination based on raw or simple fusion of raw spectra is only 95.5% and 84.4% or 99.6% and 88.5%, while the accuracy of discrimination based on nano-effect feature fusion spectra can be improved to 100%, and PLSR was used to quantify the cultivation year of the DHS with good linearity and accuracy. The nano-effect spectrum is based on the reaction of tetraphenyl zinc porphyrin (ZnTPP) with polysaccharides , flavonoids and alkaloids in DHS, which amplifies the spectral difference. This study demonstrates that multi-spectral feature vectors fusion method could potentially be a reliable analytical method to distinguish the cultivation methods and years in DHS herbs.
In this paper, glutathione (GSH)-coated Zn-doped CdTe quantum dots (QDs) with different particle sizes were synthesized using the “reflow method”, and the interaction mechanism between the two QDs and lactoferrin (LF) was investigated systemically with different spectroscopic methods. The steady-state fluorescence spectra showed that the LF formed a tight complex with the two QDs through static bursting and that the electrostatic force was the main driving force between the two LF–QDs systems. The complex generation process was found to be spontaneous (ΔG < 0) and accompanied by exothermic and increasing degrees of freedom (ΔH < 0, ΔS > 0) by using the temperature-dependent fluorescence spectroscopy. The critical transfer distance (R0) and donor–acceptor distance (r) of the two LF–QDs systems were obtained based on the fluorescence resonance energy transfer theory. In addition, it was observed that the QDs changed the secondary and tertiary structures of LF, leading to an increase in the hydrophobicity of LF. Further, the nano-effect of orange QDs on LF is much larger than that of green QDs. The above results provide a basis for metal-doped QDs with LF in safe nano-bio applications.Keywords:quantum dots (QDs);lactoferrin (LF);interaction;spectroscopic methods;thermodynamic constants;nano-effects
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