Uniform Two-Dimensional Crystalline Platelets with Tailored Compositions for pH Stimulus-Responsive Drug Release

Abstract

Two-dimensional, size-tunable, water-dispersible particle micelles with spatially defined chemistries can be obtained by using “living” crystallization-driven self-assembly (CDSA) approach. Nevertheless, a major obstacle of crystalline particles in drug delivery application is the difficulty in accessing to cargo within crystalline cores. In the present work, we design four different types of biocompatible two-dimensional platelets with a crystalline poly(ε-caprolactone) (PCL) core, a hydrophobic poly(4-vinylprydine) (P4VP) segment, and a water dispersible poly(N,N-dimethyl acrylamide) (PDMA) block in ethanol by seeded growth method. Transferring those uniform platelets with tailored compositions to an aqueous solution in the presence of a hydrophobic drug leads to efficient encapsulation of the cargo in the P4VP segments via hydrophobic interactions. These drug-loaded platelets exhibit pH-responsive release behavior in aqueous media due to the protonated–deprotonated process of P4VP blocks in acidic and neutral solutions. This work provides initial insight into biocompatible PCL platelets with low dispersity and precise chemistry control in stimulus-responsive drug delivery fields.

Precise Control of Two-Dimensional Hexagonal Platelets via Scalable, One-Pot Assembly Pathways Using Block Copolymers with Crystalline Side Chains

“…Nanoscale two-dimensional (2D) particles have received extensive interest due to their unique properties, which originate from their ultrathin planar structures. − Solution self-assembly of amphiphilic block copolymers (BCPs) is commonly a convenient route to create 2D core–shell platelet micelles with properties that are analogous to other planar nanoassemblies. − However, the fabrication of 2D platelet micelles from amorphous BCPs is generally a difficult procedure due to strict conditions required for the formation of 2D structures, such as BCP composition, solid concentration, and kinetics pathway . The recent development of crystallization-driven self-assembly (CDSA) approach provides a facile method to create anisotropic nanoparticles including one-dimensional (1D) and 2D BCP nanomaterials with tunable size, tailored composition and low particle size dispersity. − Seeded growth, also termed as “living” CDSA, has been confirmed as a powerful approach for the formation of 2D platelet micelles with precision control over their dimensions. − This has been demonstrated for polyferrocenylsilane (PFS) − and now has been extended to poly­(ε-caprolactone) (PCL) − and poly­( l -lactide) (PLLA), − where epitaxial crystallization of polymer amphiphiles to the crystalline seeds is regarded as the primary growth mechanism for the “living” CDSA (Scheme A).…”

Regulation of Two-Dimensional Platelet Micelles by Dynamic Changing of Polymer Topological Architectures upon Light Irradiation

“…The quest for facile approaches to fabricate two-dimensional (2D) soft nanomaterials with precise control of their shapes, dimensions, surface chemistries, and diverse functionalities has garnered significant interest across various fields such as catalysis, energy storage, and biomedical engineering. − A promising avenue to achieve the desired control and uniformity of 2D platelet micelles lies in the “crystallization-driven self-assembly (CDSA)” process, where epitaxial growth, driven by crystallization forces, governs the formation of anisotropic 2D core–shell nanoparticles. − In this context, amphiphilic block copolymers (BCPs) containing crystallizable core-forming blocks are widely employed as prerequisites, leading to the formation of highly stable 2D micelles in selective solvents. ,− Among various CDSA methods, seeded growth stands out as a living CDSA approach, characterized by the dynamic behavior of the active ends of seed micelles that facilitate further epitaxial growth upon the addition of unimer units. Consequently, the utilization of seeded growth holds immense promise for producing uniform micelles with precise dimensions and tailored properties. ,,− …”

Tuning the Functionality of Self-Assembled 2D Platelets in the Third Dimension

“…Crystallization-driven self-assembly (CDSA) has emerged as a powerful strategy to create 2D nanostructures of various sizes, contributing crystalline core promoted self-assembly, which allows flat platelet structures to be formed due to the low interfacial tension of the crystallized block. − For elevating the uniformity of assemblies, Manners and Winnik first reported the concept of “living” CDSA for 1D and 2D structures, where they separated the crystallite nucleation and growth processes, reducing the polydispersity of nanostructures formed. , The well-defined assemblies achieved through CDSA are versatile for a broad range of applications, − from drug delivery, − electronic devices, − and reactor substrates − to emulsion stabilizers …”