Polyethylene Glycol(PEG) is polyethylene glycol, which is non-toxic, non-irritating, has good water solubility, and has good compatibility with many organic components. They have excellent lubricity, moisture retention, dispersion, adhesive, antistatic agent and softener, etc., and are used in cosmetics, pharmaceuticals, chemical fibers, rubber, plastics, papermaking, paint, electroplating, pesticides, metal processing and food processing, etc.
Polymer/Macromolecule Product List
| CAS | Product Name | Inquiry |
| 9011-13-6 | Poly(styrene/maleic anhydride)[75:25],mw 9,500 | Inquiry |
| 100-13-0 | 4-Nitrostyrene | Inquiry |
| 100-21-0 | Terephthalic Acid | Inquiry |
| 10027-07-3 | Suberoyl Chloride | Inquiry |
| 10031-26-2 | Iron(III) bromide | Inquiry |
| 10049-08-8 | Ruthenium(III) chloride | Inquiry |
| 100-80-1 | 1-Methyl-3-ethenylbenzene | Inquiry |
| 10124-86-4 | 1,8-Diisocyanatooctane | Inquiry |
Fluorescent materials are key materials in the fields of bioimaging, photonics, and organic light-emitting diodes, and their luminous efficiency plays a vital role in technological innovation. While designing new organic dyes with better performance, it is equally important to improve the luminescence efficiency of existing dyes. Cyanine dyes are an ancient and widely used dye. They have the advantages of high molar absorption, easy wavelength control, and easy derivatization. However, they suffer from photoisomerization and aggregation fluorescence quenching in water. As a result, its fluorescence quantum yield is generally low, which greatly limits its application.
To address this problem, some researchers have developed a strategy for constructing supramolecular cyanine dyes. Starting from supramolecular chemistry, they covalently modified cyanine dyes onto self-assembled cyclic peptides to obtain luminescent units, which were then combined with cyclic peptide-PEG linkers as spacer units in aqueous solutions. Through co-assembly through multiple hydrogen bond interactions, supramolecular cyanine dyes are finally obtained. It can not only effectively inhibit the aggregation and fluorescence quenching of cyanine dyes, but also use the PEG chain around the cyclic peptide to inhibit its photoinduced cis-trans isomerization, thereby greatly improving the luminescence efficiency of cyanine dyes.
Taking Cy5 as an example, the researchers found that as the proportion of spacer units increases, the fluorescence quantum yield of the assembly increases significantly, reaching a maximum of 45.3%, while the free Cy5 dye is only 13.2%. Furthermore, using time-resolved fluorescence spectroscopy and fluorescence correlation spectroscopy (FCS), they confirmed that the photoinduced cis-trans isomerization of Cy5 was indeed inhibited in the supramolecular assembly. More importantly, due to the high local concentration of Cy5 in the assembly, its unit volume brightness is as high as 4700 M-1 cm-1 nm-3, which is close to the highest value reported in the literature. Although the driving force for the assembly of supra-cyanine dyes is non-covalent interactions, they exhibit excellent stability. Studies have found that its luminescent properties are almost unaffected in various types of aqueous media. In a wide concentration range (0.39-50 μM), the assemblies neither aggregate nor dissociate. More importantly, in the solid state, the spectrum of the material remains consistent with that of the aqueous solution, and its fluorescence quantum yield is also maintained at 37.9%.
In order to verify the universality of this supramolecular strategy, they selected cyanine dyes such as Cy2, Cy3, Cy3.5, Cy5.5, Cy7 and Cy7.5 to construct six types of supra-cyanine dyes. The fluorescence quantum yield of these six cyanine dyes in water does not exceed 15%, and the corresponding supra-cyanine dyes all exhibit excellent luminescence properties. For example, the fluorescence quantum yield of Cy3 is only 2.8%, while the fluorescence quantum yield of Supra-Cy3 is as high as 44.1%; the fluorescence quantum yield of Cy7.5 is only 0.4%, while Supra-Cy7.5 is 7.1%.
In summary, they used supramolecular strategies to prepare a series of supra-cyanine dyes whose luminescence colors cover green (Cy2), yellow (Cy3), pink (Cy3.5), red (Cy5), and near-infrared (Cy5.5 , Cy7, Cy7.5), showing excellent luminescence properties in both aqueous solution and solid state. This provides a simple and efficient supramolecular strategy for preparing ultrahigh-brightness fluorescent nanoparticles and solid-state fluorescent materials.
