Synthesis of water-soluble dye-cored poly(amidoamine) dendrimers for long-term live cell imaging

Abstract

Hydrophilic dendrimers, especially poly(amidoamine) (PAMAM) dendrimers are widely applied in modifying fluorescent dyes to endow them with water solubility and biocompatibility for biologic fluorescence imaging. Common preparation strategies of fluorescent dendrimers including encapsulating dyes or attaching dyes at periphery of dendrimers might cause uncertain constituent and lower biocompatibility. Here, we have developed a series of watersoluble fluorescent dendrimers with dye as core and fanshaped PAMAM as arms. Carboxylated perylene bisimides (PBI) dye and squarylium indocyanine (SICy) dye were conjugated with PAMAM dendrons by amidation to obtain a series of fluorescent dendrimers with enhanced water-solubility. Two PBI based dendrimers (PBI-G2.5 and PBI-G1.5) were chosen as model compounds for further optical, selfassembly and biological studies. In aqueous environment, PBI-G2.5 exhibited strong fluorescence, small size (~30 nm) and slightly positive surface charge (~2.46 mV), which are ideal for biomedical applications. In vitro assays demonstrated that PBI-G2.5 nanoparticles accumulated in the cytoplasm of HeLa cells with rapid cellular uptake. The strong fluorescence in HeLa cells remained for over 48 h. To conclude, our study provides an effective strategy for preparing water-soluble fluorescent dendrimers towards long-term live cell imaging.

Low-generation fluorescent polyurethane dendrimers via late-stage modification using azide–alkyne click chemistry

“…S35-S40. † Fluorescent PUDs (11)(12)(13)(14)(15), on the other hand, were studied by matrix-assisted laser desorption/ionization time-of-ight mass spectrometry (MALDI-TOF-MS) (Fig. 1b and S42-45 †).…”

“…10,11 Additionally, luminescence signals can be traced to obtain useful information during drug delivery 12 and biological imaging. 13,14 Late-stage modication (LSM) or post-synthetic modication is a powerful synthetic approach for synthesizing desired molecules, including dendrimers. [15][16][17] This approach not only facilitates the formation of target materials that cannot be synthesized directly but also accelerates their formation.…”

Functional organic dyes for health‐related applications

“…Recently, Yin et al developed a series of core-shell type fluorescent macromolecules. [65][66][67][68] The resulting PDI-cored star polymers or dendrimers exhibit high fluorescence quantum yields, superior photostability, and good biocompatibility, achieving efficient drug delivery and fluorescent imaging-guided cancer chemotherapy. To avoid drug leakage problems, dye-drug conjugates with stimulus labile bond are developed.…”

Near-Infrared Emitting Poly(amidoamine) Dendrimers with an Anthraquinone Core toward Versatile Non-Invasive Biological Imaging

“…This last approach has been so far the most successful way to generate poly(amidoamine) dendrimers with promising fluorescent properties. 22,23 Taking into account these previous works and considering the work of Tomalia showing that the poly(amidoamine) dendrimer have demonstrated a good biocompatibility, 24,25 but also a high water solubility to the point that they can be used as water-solubility enhancer, 20,26,27 we have decided to design, synthesize and characterize a new type of fluorescent poly(amidoamine) dendrimers in which the chromophore is located in the core of the dendrimers structure. With this strategy, the dendrimer will maintain its aqueous solubility and available functionalities at the periphery (amine or carboxylic acid functions).…”