Exploring Linker-Group-Guided Self-Assembly of Ultrathin 2D Supramolecular Nanosheets in Water for Synergistic Cancer Phototherapy

Abstract

Water is ubiquitous in natural systems where it builds an essential environment supporting biological supramolecular polymers to function, transport, and exchange. However, this extreme polar environment becomes a hindrance for the superhydrophobic functional π-conjugated molecules, causing significant negative impacts on regulating their aggregation pathways, structures, and properties of the subsequently assembled nanomaterials. It especially makes the self-assembly of ultrathin twodimensional (2D) functional nanomaterials by π-conjugated molecules a grand challenge in water, although ultrathin 2D functional nanomaterials have exhibited unique and superior properties. Herein, we demonstrate the organic solvent-free self-assembly of onemolecule-thick 2D nanosheets based on exploring how side chain modifications rule the aggregation behaviors of π-conjugated macrocycles in water. Through an in-depth understanding of the roles of linking groups for side chains on affecting the aggregation behaviors of porphyrins in water, the regulation of molecular arrangement in the aggregated state (H-or J-type aggregation) was attained. Moreover, by arranging ionic porphyrins into 2D single layers through J-aggregation, the ultrathin nanosheets (thickness ≈ 2 nm) with excellent solubility and stability were self-assembled in pure water, which demonstrated both outstanding 1 O 2 generation and photothermal capability. The ultrathin nanosheets were further investigated as metal-and carrier-free nanodrugs for synergetic phototherapies of cancers both in vitro and in vivo, which are highly desirable by combining the advantages and avoiding the disadvantages of the single use of PDT or PTT.

Two-Dimensional Molecular Architectonics through Controlled Noncovalent Interactions: Structure, Functional Properties, and Applications

“…Achieving precise control over noncovalent interactions at the molecular level is a challenging task in mastering the art of engineering molecular organization into functional architectures. In this context, the strategy of engineering molecular assemblies of designer modular functional cores by functionalizing with suitable biomolecules or their biomimetics as auxiliaries to fabricate functional 1D, 2D, 3D, and hierarchical architectures of well-defined shape, size, and properties is conceptualized as molecular architectonics. − In recent years, 2D architectures have gained prominence due to their exotic structure, properties, and applications. − The scheme of molecular architectonics allows the fabrication of molecular and material architectures through 2D molecular organization, offering vast opportunities. − ,− In nature, biomolecules have built-in information for molecular recognition to undergo ordered and hierarchical molecular organization through controlled and synchronized noncovalent interactions to form biological materials of varied dimension and hierarchy with predefined structure and functions. The development of 2D material architectures by adopting nature-inspired design strategies addresses problems in the domains of health, energy, and environment. − Molecular architectonics guide the fabrication of 2D material architectures with functional properties and technological applications .…”