Divergent self-assembly propensity of enantiomeric phenylalanine amphiphiles that undergo pH-induced nanofiber-to-nanoglobule conversion.

This study presents the pathway diversity in the self-assembly of enantiomeric single phenylalanine derived amphiphiles (single F-PDAs), L-NapF-EDA and D-NapF-EDA, that form supramolecular hydrogels at varied concentrations (≥1 mg mL and ≥3 mg mL, respectively). By fitting the variable temperature circular dichroism (VT-CD) data to the isodesmic model, various thermodynamic parameters associated with their self-assembly, such as association constant (), changes in enthalpy (Δ), entropy (Δ), and Gibbs free energy (Δ), were extracted. The self-assembly of these single F-PDAs was found to be enthalpy-driven but entropically-disfavored.

Enzymatic Dimerization-Induced Self-Assembly of Alanine-Tyramine Conjugates into Versatile, Uniform, Enzyme-Loaded Organic Nanoparticles.

Herein, we report a novel enzymatic dimerization-induced self-assembly (e-DISA) procedure that converts alanine-tyramine conjugates into highly uniform enzyme-loaded nanoparticles (NPs) or nanocontainers by the action of horseradish peroxidase (HRP) in an aqueous medium under ambient conditions. The NP formation was possible with both enantiomers of alanine, and the average diameter could be varied from 150 nm to 250 nm (with a 5-12 % standard deviation of as-prepared samples) depending on the precursor concentration. About 60 % of the added HRP enzyme was entrapped within the NPs and was subsequently utilized for post-synthetic modification of the NPs with phenolic compounds such as tyramine or tannic acid.

Anion-responsive self-assembled hydrogels of a phenylalanine-TREN conjugate allow sequential release of propranolol and doxorubicin.

Stimuli-responsive self-assembled and supramolecular hydrogels derived from peptide amphiphiles have opened exciting new avenues in biomedicine and drug delivery. Herein, we screened a series of phenylalanine-amphiphiles possessing polyamine and oxyethylene appendages for their self-assembly and anion-responsiveness and found that the tris(aminoethyl)amine (TREN) containing amphiphile NapF-TREN formed injectable hydrogels that could be disrupted upon the addition of stoichiometric amounts of tetrahedral monovalent anions such as HPO and HSO, while the addition of other anions such as Cl, HPO, CO, HCO or SO did not affect the gel stability. The anion-gelator interaction was investigated by H and P NMR spectroscopy as well as by Isothermal Titration Calorimetry (ITC).

Hydrogel-mediated topical delivery of steroids can effectively alleviate psoriasis attenuating the autoimmune responses.

Psoriasis is a systemic, relapsing, and chronic autoimmune inflammatory disease of the skin. Topical use of betamethasone, a glucocorticoid, in the form of creams is a common treatment for psoriasis. However, topical use of these creams is challenging due to the ineffective entrapment of steroids, burst release of the entrapped drugs, poor skin permeability, and high toxicity.

Nonimmunogenic Hydrogel-Mediated Delivery of Antibiotics Outperforms Clinically Used Formulations in Mitigating Wound Infections.

Treatment of chronic wound infections caused by Gram-positive bacteria such as is highly challenging due to the low efficacy of existing formulations, thereby leading to drug resistance. Herein, we present the synthesis of a nonimmunogenic cholic acid-glycine-glycine conjugate () that self-assembles into a supramolecular viscoelastic hydrogel ( gel) suitable for topical applications. The hydrogel can entrap different antibiotics with high efficacy without compromising its viscoelastic behavior.