Single-component nanodiscs via the thermal folding of amphiphilic graft copolymers with the adjusted flexibility of the main chain

Poly(2-oxazoline)-Based Thermoresponsive Stomatocytes

The design of biocompatible and biodegradable nanostructures with controlled morphological features remains a predominant challenge in medical research. Stimuli-responsive vesicles offer significant advantages in drug delivery, biomedical applications, and diagnostic techniques. The combination of poly(2-oxazoline)s with biodegradable polymers could provide exceptional biocompatibility properties and be proposed as a versatile platform for the development of new medicines. Therefore, poly(2-ethyl-2-oxazoline) (PEtOx) and poly(2-isopropyl-2-oxazoline) (PiPrOx) possessing a hydroxy terminal group that acts as an initiator for the ring-opening polymerization of d,l-lactide (DLLA) have been utilized in this study. The resulting amphiphilic block polymers were used to create polymersomes, which undergo solvent-dependent reorganization into bowl-shaped vesicles or stomatocytes. By blending PEtOx-b-PDLLA and PiPrOx-b-PDLLA copolymers, a thermoresponsive stomatocyte was generated, where the opening narrowed and irreversibly closed with a slight increase in the temperature. Detailed transmission electron microscopy analysis reveals the formation of both closed and fused stomatocytes upon heating the sample above the critical solution temperature of PiPrOx.

Manipulation of Macrophage Uptake by Controlling the Aspect Ratio of Graft Copolymer Micelles

Nanostructures of drug carriers play a crucial role in nanomedicine due to their ability to influence drug delivery. There is yet no clear consensus regarding the optimal size and shape (e.g., aspect ratio) of nanoparticles for minimizing macrophage uptake, given the difficulties in controlling the shape and size of nanoparticles while maintaining identical surface properties. Here, we employed graft copolymer self-assembly to prepare polymer micelles with aspect ratios ranging from 1.0 (spherical) to 10.8 (cylindrical) and closely matched interfacial properties. Notably, our findings emphasize that cylindrical micelles with an aspect ratio of 2.4 are the least susceptible to macrophage uptake compared with both their longer counterparts and spherical micelles. This reduced uptake of the short cylindrical micelles results in a 3.3-fold increase in blood circulation time compared with their spherical counterparts. Controlling the aspect ratio of nanoparticles is crucial for improving drug delivery efficacy through better nanoparticle design.

Rationally designed block copolymer-based nanoarchitectures: An emerging paradigm for effective drug delivery

Various polymeric materials have been investigated to produce unique modes of delivery for drug modules to achieve either temporal or spatial control of bioactives delivery. However, after intravenous administration, phagocytic cells quickly remove these nanostructures from the systemic circulation via the reticuloendothelial system (RES). To overcome these concerns, ecofriendly block copolymers are increasingly being investigated as innovative carriers for the delivery of bioactives. In this review, we discuss the design, fabrication techniques, and recent advances in the development of block copolymers and their applications as drug carrier systems to improve the physicochemical and pharmacological attributes of bioactives.

Facile preparation of hexagonal nanosheets via polyion complex formation from α-helical polypeptides and polyphosphate-based molecules

The polyion complex-based supramolecular self-assembly of hexagonal nanosheets was achieved via the complexation of a PEGylated block catiomer with ATP and other polyphosphate-containing small molecules. The formation of hexagonal nanosheets required the presence of a polyethylene glycol block and α-helix formation in the catiomer block, which was induced by complexation with the polyphosphate moiety.

Formulation of water-dispersible hydrophobic compound nanocomplexes with polypeptides via a supramolecular approach using a high-speed vibration milling technique

Polypeptides were used to solubilize functional hydrophobic molecules via a high-speed vibrational milling method. Poly-l-lysine and poly-γ-glutamic acid, which are polypeptides, were able to prepare more highly concentrated water-dispersible complexes of hydrophobic compounds, including fullerenes, organic dyes, and porphyrin derivatives, than conventional water solubilizers, such as cyclodextrins and pullulan. In addition, the polypeptide systems endowed the complexes with long-term stability and resistance against thermal stress, which is advantageous for industrial applications. Furthermore, complexes of polypeptides and porphyrin derivatives showed a photodynamic activity against cancer cells, and the current system improved the dispersibility and storability of guest molecules without compromising their functionality.

Recent advances in the self-assembly of sparsely grafted amphiphilic copolymers in aqueous solution

This review describes the self-assembly of sparsely grafted amphiphilic copolymers and highlights the effects of structural factors and solvents on their self-assembly behaviour.