Polycondensation of a Perylene Bisimide Derivative and L-Malic Acid as Water-Soluble Conjugates for Fluorescent Labeling of Live Mammalian Cells

Abstract

Based on simple mixing and polymerization of a hydroxyl-containing derivative of perylene bisimide (PBI) and l-malic acid, here, we demonstrate a new type of dye-polymer conjugate, PBI-poly(α,β-malic acid) (PBI–PMA). Benefiting from the excellent water-solubility of weak polyanionic PMA structure and the high fluorescence of PBI, the PBI-PMA conjugates readily dissolve in water, displaying strong pH-dependent fluorescence with the highest intensity at pH 6. Due to the excellent biocompatibility of PMA, those conjugates showed low cytotoxicity on L929 cells. Using L929 and HeLa cells, we also confirmed that the PBI-PMA-labeled cells display intense fluorescence. Overall, the PBI-PMA conjugate demonstrates high potential as a cell labeling agent with its synthesis ease, good solubility in aqueous medium, low cytotoxicity, and high fluorescence.

Recent Advances in Applications of Fluorescent Perylenediimide and Perylenemonoimide Dyes in Bioimaging, Photothermal and Photodynamic Therapy

“…Starting from this PDI-OH derivative, a one-step polycondensation was carried out in the presence of L-malic acid under vacuum, affording a PDI-poly( α , β -malic acid) named PDI-PMA of a high molecular weight around 5.8 kDa ( Figure 7 ) [ 104 ]. This polymer introduced 3%wt PDI-OH, and the presence of two hydroxyl groups on the PDI starting material did not induce cross-linking in the resulting polymer.…”

Amphiphilic Perylene Bisimide–Polymer Conjugates by Cysteine-Based Orthogonal Strategy: Vesicular Aggregation, DNA Binding, and Cell Imaging

“…For instance, the attachment of lower critical solution temperature (LCST)-type PNIPAM can be used for tuning fluorescence properties of PBIs by changing temperature in water . The attachment of polyanionic poly­(α,β-malic acid) (PMA) with PBI produces a conjugate whose fluorescence properties can be tuned by varying the solution pH . Thus, there are still immense scopes to develop different kinds of new stimuli-responsive PBI–polymer conjugates with tunable fluorescence properties, which find applications as sensory materials for chemo- and biosensors.…”

“…Green-yellow emitting water-soluble PBI dyes are very interesting materials with huge potential for applications in biology and biotechnology. In this direction, highly water-soluble biocompatible PBI–polymer conjugates with low cytotoxicity were developed to use them as fluorescent probes for labeling of living cells. ,,,,, PBIs containing hydrophilic small molecules have also been used for labeling of living cells and for other biological applications. ,− Beside cell imaging applications, the binding capability of water-soluble PBI-small molecular conjugates with DNA has also been studied by many research groups. ,,, However, most of these studies were focused on the investigation of intercalations of PBIs with DNA as well as their applications in living cell. Furthermore, it is also known that cationic/noncationic polymers can form stable polyplexes with DNA/RNA through electrostatic interactions, which have been studied in detail by several researchers including our groups. − Therefore, the binding of amphiphilic PBI–polymer conjugate with DNA would certainly be interesting to study.…”

“…17 The attachment of polyanionic poly(α,β-malic acid) (PMA) with PBI produces a conjugate whose fluorescence properties can be tuned by varying the solution pH. 21 Thus, there are still immense scopes to develop different kinds of new stimuliresponsive PBI−polymer conjugates with tunable fluorescence properties, which find applications as sensory materials for chemo-and biosensors.…”

“…In this direction, highly watersoluble biocompatible PBI−polymer conjugates with low cytotoxicity were developed to use them as fluorescent probes for labeling of living cells. 4,6,19,21,27,28 PBIs containing hydrophilic small molecules have also been used for labeling of living cells and for other biological applications. 16,29−31 Beside cell imaging applications, the binding capability of water-soluble PBI-small molecular conjugates with DNA has also been studied by many research groups.…”