Water-Soluble Fluorescent Nanoparticles from Supramolecular Amphiphiles Featuring Heterocomplementary Multiple Hydrogen Bonding

Bioinspired and biomimetic nucleobase-containing polymers: the effect of selective multiple hydrogen bonds

Bioinspired and biomimetic nucleobase-containing polymers are a series of polydisperse nucleic acid analogs, mainly obtaining through highly efficient and scalable step-growth or chain polymerizations. The combination of pendant nucleobase groups and various backbones endows the polymers/materials with selective multiple H-bonds under distinct conditions, demonstrating the broad applicability of this new family of polymeric materials. In this perspective, we critically summarize recent advances of bioinspired and biomimetic nucleobase-containing polymers and materials in both solution and the bulk. Then, we discuss the effect of multiple H-bonds between complementary nucleobases on the structures and properties of the nucleobase-containing polymers and materials. Selective multiple H-bonds between complementary nucleobases are feasible to modulate the polymer sequence and self-assembly behaviour, achieve templated polymerization, tune nanostructure morphologies and functions, and selectively bind with nucleic acids in various solutions. Meanwhile, bioinspired and biomimetic nucleobase-containing polymers are capable of forming robust polymeric materials such as hydrogels, bioplastics, elastomers, adhesives, and coatings by optimizing the inter- and intramolecular multiple H-bonding interactions. Further, the conclusions and outlook for future development and challenges of bioinspired and biomimetic nucleobase-containing polymers are also presented. This perspective presents useful guidelines for fabricating novel bioinspired and biomimetic polymers and materials through rational design of multiple H-bonds nucleobase interactions.

Switchable pH-Responsive Morphologies of Coassembled Nucleobase Copolymers

This work presents supramolecular coassembled nucleobase copolymers with transitional morphologies upon pH changes (from 7.4 to 10). Uracil- and adenine-containing copolymers were prepared by RAFT, which allowed us to finely tailor the polymerization degree and the composition. The coassembled formulations prepared in an aqueous buffer at two distinct pH (7.4 and 10) formed spherical morphologies at physiological pH. The increase of the pH induced the apparition of various large, irreversible anisotropic supramolecular architectures. Isothermal titration calorimetry revealed that the coassembly at pH 7.4 was mainly guided by H-bonds between complementary nucleobases, while the experiments conducted at pH 10 showed that the assemblies were mainly driven by hydrophobic interactions. These results highlight that the nature of supramolecular interactions (H-bonds or hydrophobic interactions) has a great influence on the morphology of nucleobase-containing coassemblies when changing the pH. These findings may provide further perspectives in the field of advanced nanomaterials.

Controlled node growth on the surface of polymersomes

Incorporating nucleobases into synthetic polymers has proven to be a versatile method for controlling self-assembly. The formation of strong directional hydrogen bonds between complementary nucleobases provides a driving force that permits access to complex particle morphologies. Here, nucleobase pairing was used to direct the formation and lengthening of nodes on the outer surface of vesicles formed from polymers (polymersomes) functionalised with adenine in their membrane-forming domains. Insertion of a self-assembling short diblock copolymer containing thymine into the polymersome membranes caused an increase in steric crowding at the hydrophilic/hydrophobic interface, which was relieved by initial node formation and subsequent growth. Nano-objects were imaged by (cryo-)TEM, which permitted quantification of node coverage and length. The ability to control node growth on the surface of polymersomes provides a new platform to develop higher-order nanomaterials with tailorable properties.

Hydrogen-Bonding Interactions from Nucleobase-Decorated Supramolecular Polymer: Synthesis, Self-Assembly and Biomedical Applications

The fabrication of supramolecular materials for biomedical applications such as drug delivery, bioimaging, wound-dressing, adhesion materials, photodynamic/photothermal therapy, infection control (as antibacterial), etc. has grown tremendously, due to their unique properties, especially the formation of hydrogen bonding. Nevertheless, void space in the integration process, lack of feasibility in the construction of supramolecular materials of natural origin in living biological systems, potential toxicity, the need for complex synthesis protocols, and costly production process limits the actual application of nanomaterials for advanced biomedical applications. On the other hand, hydrogen bonding from nucleobases is one of the strategies that shed light on the blurred deployment of nanomaterials in medical applications, given the increasing reports of supramolecular polymers that promote advanced technologies. Herein, we review the extensive body of literature about supramolecular functional biomaterials based on nucleobase hydrogen bonding pertinent to different biomedical applications. It focuses on the fundamental understanding about the synthesis, nucleobase-decorated supramolecular architecture, and novel properties with special emphasis on the recent developments in the assembly of nanostructures via hydrogen-bonding interactions of nucleobase. Moreover, the challenges, plausible solutions, and prospects of the so-called hydrogen bonding interaction from nucleobase for the fabrication of functional biomaterials are outlined.

Nucleobase-Interaction-Directed Biomimetic Supramolecular Self-Assembly

ConspectusThe design and fabrication of synthetic self-assembled systems that can mimic some biological features require exquisitely sophisticated components that make use of supramolecular interactions to attain enhanced structural and functional complexity. In nature, nucleobase interactions play a key role in biological functions in living organisms, including transcription and translation processes. Inspired by nature, scientists are progressively exploring nucleobase synthons to create a diverse range of functional systems with a plethora of nanostructures by virtue of molecular-recognition-directed assembly and flexible programmability of the base-pairing interactions. To that end, nucleobase-functionalized molecules and macromolecules are attracting great attention because of their versatile structures with smart and adaptive material properties such as stimuli responsiveness, interaction with external agents, and ability to repair structural defects. In this regard, a range of nucleobase-interaction-mediated hierarchical self-assembled systems have been developed to obtain biomimetic materials with unique properties. For example, a new "grafting to" strategy utilizing complementary nucleobase interactions has been demonstrated to temporarily control the functional group display on micellar surfaces. In a different approach, complementary nucleobase interactions have been explored to enable morphological transitions in functionalized diblock copolymer assembly. It has been demonstrated that complementary nucleobase interactions can drive the morphological transformation to produce highly anisotropic nanoparticles by controlling the assembly processes at multiple length scales. Furthermore, nucleobase-functionalized bottle brush polymers have been employed to generate stimuli-responsive hierarchical assembly. Finally, such interactions have been exploited to induce biomimetic segregation in polymer self-assembly, which has been employed as a template to synthesize polymers with narrow polydispersity. It is evident from these examples that the optimal design of molecular building blocks and precise positioning of the nucleobase functionality are essential for fabrication of complex supramolecular assemblies. While a considerable amount of research remains to be explored, our studies have demonstrated the potential of nucleobase-interaction-mediated supramolecular assembly to be a promising field of research enabling the development of biomimetic materials.This Account summarizes recent examples that employ nucleobase interactions to generate functional biomaterials by judicious design of the building blocks. We begin by discussing the molecular recognition properties of different nucleobases, followed by different strategies to employ nucleobase interactions in polymeric systems in order to achieve self-assembled nanomaterials with versatile properties. Moreover, some of their prospective biological/material applications such as enhanced drug encapsulation, superior adhesion, and fast self-healing properties facilitated by complementary nucleobase interactions are emphasized. Finally, we identify issues and challenges that are faced by this class of materials and propose future directions for the exploration of functional materials with the aim of promoting the development of nucleobase-functionalized systems to design the next generation of biomaterials.

Supramolecular co-assembly of water-soluble nucleobase-containing copolymers: bioinspired synthetic platforms towards new biomimetic materials

This study presents the development of new co-assembled copolymers architectures at physiological pH (pH=7.4) formed via H-bonds between complementary nucleobase-containing copolymers. Well-defined hydrophilic copolymers were synthesised by RAFT polymerisation: statistical...

Nucleobase-containing polymer architectures controlled by supramolecular interactions: the key to achieve biomimetic platforms with various morphologies

Challenges and opportunities in supramolecular self-assembly of synthetic nucleobase-containing copolymers.

Functional Systems Derived from Nucleobase Self-assembly

Dynamic and reversible non-covalent interactions endow synthetic systems and materials with smart adaptive functions that allow them to response to diverse stimuli, interact with external agents, or repair structural defects. Inspired by the outstanding performance and selectivity of DNA in living systems, scientists are increasingly employing Watson-Crick nucleobase pairing to control the structure and properties of self-assembled materials. Two sets of complementary purine-pyrimidine pairs (guanine:cytosine and adenine:thymine(uracil)) are available that provide selective and directional H-bonding interactions, present multiple metal-coordination sites, and exhibit rich redox chemistry. In this review, we highlight several recent examples that profit from these features and employ nucleobase interactions in functional systems and materials, covering the fields of energy/electron transfer, charge transport, adaptive nanoparticles, porous materials, macromolecule self-assembly, or polymeric materials with adhesive or self-healing ability.

Supramolecular nucleobase-functionalized polymers: synthesis and potential biological applications

This Perspective article summarizes the synthesis of nucleobase functionalized polymers and highlights issues and challenges following their potential biological applications.

Self-Assembled Structures of Diblock Copolymer/Homopolymer Blends through Multiple Complementary Hydrogen Bonds

A poly(styrene-b-vinylbenzyl triazolylmethyl methyladenine) (PS-b-PVBA) diblock copolymer and a poly(vinylbenzyl triazolylmethyl methylthymine) (PVBT) homopolymer were prepared through a combination of nitroxide-mediated radical polymerizations and click reactions. Strong multiple hydrogen bonding interactions of the A···T binary pairs occurred in the PVBA/PVBT miscible domain of the PS-b-PVBA/PVPT diblock copolymer/homopolymer blend, as evidenced in Fourier transform infrared and 1H nuclear magnetic resonance spectra. The self-assembled lamellar structure of the pure PS-b-PVBA diblock copolymer after thermal annealing was transformed to a cylinder structure after blending with PVBT at lower concentrations and then to a disordered micelle or macrophase structure at higher PVBT concentrations, as revealed by small-angle X-ray scattering and transmission electron microscopy.

Stimuli-responsive supramolecular conjugated polymer with phototunable surface relief grating

A facile method to synthesize azobenzene- and thymine (T)-functionalized conjugated copolymers through Suzuki coupling polymerization and click reactions and used in surface relief gratings displaying long-range-ordered interference patterns.