Supramolecular Vector/Drug Coassemblies of Polyglycerol Dendrons and Rutin Enhance the pH Response

Visible Light-Responsive Composition-Dependent Morphology and Cargo Release in Mixed Micelles of Dendron Amphiphiles

2,2-Bis-(methylol)propionic acid-based second-generation polyester dendron amphiphile (T-D) containing visible light-responsive donor-acceptor Stenhouse adduct (DASA) as hydrophobic tails is synthesized. Micelles of T-D amphiphile and its mixed micelles of varying compositions with nonresponsive dendron amphiphile containing lauryl groups are prepared in aqueous solution. In transmission electron microscopy and atomic force microscopy analyses, T-D amphiphiles show rice grain-like ellipsoidal micelles as the predominant morphology. Mixed micelles display a composition-dependent morphology gradient such that the morphology changes from rice grain like to mixed to completely spherical with decreasing content of the T-D amphiphile. Complete morphology change to spherical micelles and partial reversal to ellipsoidal micelles, finally leading to ill-defined aggregates, are observed when the T-D amphiphile micelles are subjected to visible light-dark storage photoswitching cycles. Small-angle neutron scattering (SANS) analysis of 1 wt.% micellar solution in THF:water (10:90) reveals only a minor change in shape and size upon photoirradiation, and the data could be fitted to spherical or ellipsoidal model. Release of hydrophobic dye from mixed micelles is tuned by the content of the photoresponsive amphiphile. Cellular uptake and visible light-triggered release of hydrophobic drug from mixed micelles are demonstrated using MDA-MB-231 cells, suggesting their applicability for photoresponsive drug delivery.

Activation and Inhibition of Isomerization of a Cationic Azobenzene Surfactant in the Large Void Space of Polyglycerol Dendron Micelles

Owing to the unique geometric structure of dendritic amphiphiles with voluminous dendrons, their micelles can harbor a large void space, which provides a new research focus and approach for micellar functionalization. In this work, we used the void space to construct a UV responsive micelle system of the mixed dendritic amphiphile (C₁₂-(G3)₂) and cationic azobenzene surfactant (C4AzoTAB). The synthesized C₁₂-(G3)₂ that possesses double third generation polyglycerol (PG) dendrons and a single alkyl chain is expected to highlight the large void space within the inside of the micelles. Thus, the aims of this work are to achieve the isomerization of C4AzoTAB in situ and to deeply understand the intermolecular interaction in the mixed micelles. The effect of the large void room with a wall decorated with the ether oxygen atoms on the isomerization of C4AzoTAB was studied by isomerization kinetics, conductivity measurements, isothermal titration calorimetry (ITC), and ¹H NMR and 2D NOESY spectroscopies. The isomerization behavior of C4AzoTAB in C₁₂-(G3)₂ micelles was presented in terms of its kinetic constant, counterionic association, interaction enthalpy, and position and orientation of C4AzoTAB. The results of NMR and conductivity show that the quaternary ammonium group of C4AzoTAB situates on the surface of the mixed micelles with C₁₂-(G3)₂ both before and after UV-irradiation, while the position of azobenzene group in C₁₂-(G3)₂ micelles depends on its conformation. The C₁₂-(G3)₂ micelles can inhibit the UV response of the trans-isomer and activate the thermal relaxation of the cis-isomer, which has a potential application in the field of light-controlled smart nanocarriers.

Modulating Inflammation-Mediated Diseases via Natural Phenolic Compounds Loaded in Nanocarrier Systems

The global increase and prevalence of inflammatory-mediated diseases have been a great menace to human welfare. Several works have demonstrated the anti-inflammatory potentials of natural polyphenolic compounds, including flavonoid derivatives (EGCG, rutin, apigenin, naringenin) and phenolic acids (GA, CA, etc.), among others (resveratrol, curcumin, etc.). In order to improve the stability and bioavailability of these natural polyphenolic compounds, their recent loading applications in both organic (liposomes, micelles, dendrimers, etc.) and inorganic (mesoporous silica, heavy metals, etc.) nanocarrier technologies are being employed. A great number of studies have highlighted that, apart from improving their stability and bioavailability, nanocarrier systems also enhance their target delivery, while reducing drug toxicity and adverse effects. This review article, therefore, covers the recent advances in the drug delivery of anti-inflammatory agents loaded with natural polyphenolics by the application of both organic and inorganic nanocarriers. Even though nanocarrier technology offers a variety of possible anti-inflammatory advantages to naturally occurring polyphenols, the complexes' inherent properties and mechanisms of action have not yet been fully investigated. Thus, expanding the quest on novel natural polyphenolic-loaded delivery systems, together with the optimization of complexes' activity toward inflammation, will be a new direction of future efforts.