Controlled Synthesis of Dendrite-like Polyglycerols Using Aluminum Complex for Biomedical Applications

This work describes a one-pot synthesis of dendrite-like hyperbranched polyglycerols (HPGs) via a ring-opening multibranching polymerization (ROMBP) process using a bis(5,7-dichloro-2-methyl-8-quinolinolato)methyl aluminum complex (1) as a catalyst and 1,1,1-tris(hydroxymethyl)propane/trimethylol propane (TMP) as an initiator. Single-crystal X-ray diffraction (XRD) analysis was used to elucidate the molecular structure of complex 1. Inverse-gated (IG)¹³C NMR analysis of HPGs showed degree of branching between 0.50 and 0.57. Gel permeation chromatography (GPC) analysis of the HPG polymers provided low, medium, and high-molecular weight (M _n) polymers ranging from 14 to 73 kDa and molecular weight distributions (M _w/M _n) between 1.16 and 1.35. The obtained HPGs exhibited high wettability with water contact angle between 18 and 21° and T _g ranging between -39 and -55 °C. Notably, ancillary ligand-supported aluminum complexes as catalysts for HPG polymerization reactions have not been reported to date. The obtained HPG polymers in the presence of the aluminum complex (1) can be used for various biomedical applications. Here, nanocomposite electrospun fibers were fabricated with synthesized HPG polymer. The nanofibers were subjected to cell culture experiments to evaluate cytocompatibility behavior with L929 and MG63 cells. The cytocompatibility studies of HPG polymer and nanocomposite scaffold showed high cell viability and spreading. The study results concluded, synthesized HPG polymers and composite nanofibers can be used for various biomedical applications.

Amphiphilic hyperbranched polyglycerol nanoarchitectures for Amphotericin B delivery in Candida infections

Although Amphotericin B (AMB) is considered the most effective anti-mycotic agent for treating Candida infections, its clinical use is limited due to its high toxicity. To address this issue, we developed cholesterol-based dendritic micelles of hyperbranched polyglycerol (HPG), including cholesterol-cored HPG (Chol-HPG) and cholesterol end-capped HPG (HPG@Chol), for AMB delivery. The findings suggested that the presence of cholesterol moieties could control AMB loading and release properties. Dendritic micelles inhibited AMB hemolysis and cytotoxicity in HEK 293 and RAW 264.7 cell lines while increasing antifungal activity against C. albicans biofilm formation. Furthermore, significantly lower levels of renal and liver toxicity biomarkers compared to Fungizone® ensured AMB-incorporated dendritic micelle biosafety, which was confirmed by histopathological evaluations. Overall, the Chol-HPG and HPG@Chol dendritic micelles may be a viable alternative to commercially available AMB formulations as well as an effective delivery system for other poorly soluble antifungal agents.

Poly(ionic liquid)s with superior swelling and enrichment properties in solvents

The molar swelling ratio and enrichment factor of poly(ionic liquid)s were linearly positively correlated with the Hansen solubility parameter of the solvent and the difference between the Hansen solubility parameters of mixed solvents, respectively.

Hyperbranched Polyglycerols as Robust Up-Conversion Nanoparticle Coating Layer for Feasible Cell Imaging

Owing to the wide spectrum of excitation wavelengths of up-conversion nanoparticles (UCNPs) by precisely regulating the percentage of doping elements, UCNPs have been emerging as bioimaging agents. The key drawback of UCNPs is their poor dispersibility in aqueous solution and it is hard to introduce the chemical versatility of function groups. In our study, we present a robust and feasible UCNP modification approach by introducing hyperbranched polyglycerols (hbPGs) as a coating layer. When grafted by hbPGs, the solubility and biocompatibility of UCNPs are significantly improved. Moreover, we also systematically investigated and optimized the chemical modification approach of amino acids or green fluorescence protein (GFP), respectively, grafting onto hbPGs and hbPGs-g-UCNP by oxidizing the vicinal diol to be an aldehyde group, which reacts more feasibly with amino-containing functional molecules. Then, we investigated the drug-encapsulating properties of hbPGs-Arg with DOX and cell imaging of GFP-grafted hbPGs-g-UCNP, respectively. The excellent cell imaging in tumor cells indicated that hbPG-modification of UCNPs displayed potential for applications in drug delivery and disease diagnosis.

Facile synthesis of amphiphilic peach gum polysaccharide as a robust host for efficient encapsulation of methylene blue and methyl orange dyes from water

Despite impressive progress of macromolecular encapsulation technique based on hyperbranched polymer (HP), the use of natural HP for guest encapsulation has rarely been reported. Herein, we present the simple synthesis of amphiphilic PGP-DC from natural peach gum polysaccharide (PGP) and demonstrate that the PGP-DC can be utilized as a robust host for encapsulation of dye molecules from water. The influences of initial dye concentration, dosage of PGP-DC, pH, ionic strength, and encapsulation mode on the encapsulation were systematically studied. The PGP-DC simultaneously exhibited fast encapsulation rate and superior encapsulation capability. Under optimal conditions, the encapsulation capacity of PGP-DC towards methylene blue (MB) (1 mM) can reach as high as 182.67 mg/g, which compares favorably to other separation techniques. Moreover, the MB-encapsulated PGP-DC could be well regenerated in acidic solution. Based on its simple synthetic process, excellent encapsulation performance and fine reusability, the PGP-DC holds great promise for using as a host for practical encapsulation applications.

Design of fluorinated hyperbranched polyether copolymers for 19F MRI nanotheranostics

¹⁹F MRI contrast agents and drug nanocarriers based on fluorinated hyperbranched polyether copolymers.