Unravelling the pore network and gas dynamics in highly adaptive rubbery organic frameworks

Rubbery organic frameworks-ROFs have recently emerged as an intriguing class of dynamers by virtue of reversible connections between their building units. Their highly adaptative features at the origin of their spectacular self-healing properties made them also attractive candidates for the development of gas-selective membranes combining high selectivity and fast permeability. So far, little is known on the origin of this unique trait and this clearly hampers the exploitation of this class of dynamers in many areas where stimuli-responsive pore dynamics is of great importance. To address this lack of fundamental knowledge, herein we unravel the self-assembly process of ROFs via the development of an advanced computational methodology combining quantum and force field molecular simulations that enable the description of reversible connections of building units and the long-range organization of the cross-linked ROF network. We demonstrate that both accurate energy barriers associated with the covalent bond formation between the building units and presence of solvent are key parameters to ensure the in silico construction of reliable ROF structure models that are supported by a set of experimental data collected on synthesized ROFs including density, connectivity and porosity. Atomistic insights into the unusual guest-responsive pore dynamics of this intriguing class of dynamers are further gained with a special attention paid to the tunability of this pore flexibility by controlling the chemical composition of the building units. As a further stage, the dynamics of CO₂ in these compliance frameworks is scrutinized to shed light on the mechanism at the origin of their promising performance as CO₂-selective membranes. We highlight that guest-triggered pore dynamics enables the creation of a diffusion pathway to ensure effective gas transport throughout the whole ROF. This knowledge of the pore structure and its guest-responsive dynamics at the microscopic level is unprecedented in the field of dynamers and it is expected to pave the way towards the optimization of this class of adaptive porous frameworks for many potential applications. Interestingly, this computational approach can be transferable to the exploration of any complex disordered systems showing a high degree of flexibility and guest induced structure/pore reorganization.

Structure and gas transport molecular insight into the intriguing rubbery organic frameworks characterized by unique adaptative behavior owing to the reversible connections between their constitutive building units and their non-permanent porosity.

Cationic dynamic covalent polymers for gene transfection

Dynamic covalent polymers have revealed strong potential in gene delivery, thanks to their versatile self-assembly, adaptive and responsive behaviors.

Dynamic constitutional frameworks for DNA biomimetic recognition

Linear and cross-linked dynamic constitutional frameworks generated from reversibly interacting linear PEG/core constituents and cationic sites shed light on the dominant coiling versus linear DNA binding behaviours, closer to the histone DNA binding wrapping mechanism.

Dynamic constitutional frameworks (DCFs) as nanovectors for cellular delivery of DNA

We introduce Dynamic Constitutional Frameworks (DCFs), macromolecular structures that efficiently bind and transfect double stranded DNA. DCFs are easily synthesizable adaptive 3D networks consisting of core connection centres reversibly linked via labile imine bonds both to linear polyethyleneglycol (PEG, ∼1500 Da) and to branched polyethyleneimine (bPEI, ∼800 Da). DCFs bind linear and plasmid DNA, forming particulate polyplexes of 40-200 nm in diameter. The polyplexes are stable during gel electrophoresis, well tolerated by cells in culture, and exhibit significant transfection activity. We show that an optimal balance of PEG and bPEI components is important for building DCFs that are non-toxic and exhibit good cellular transfection activity. Our study demonstrates the versatility and effectiveness of DCFs as promising new vectors for DNA delivery.

Chemo- and stereoselective synthesis of fluorinated enamides from ynamides in HF/pyridine: second-generation approach to potent ureas bioisosteres

(E)- and (Z)-α-fluoroenamides could be easily prepared with high levels of chemo- and regioselectivities by hydrofluorination of readily available ynamides with HF/pyridine. The scope and limitations of this new process for the hydrofluorination of ynamides, as well as the stability of the resulting α-fluoroenamides, have been extensively studied. Theoretical calculations at the MP2 and B3LYP levels of theory showed that the resulting fluoroenamides exhibit geometrical and electronic properties that partially mirror those of ureas, therefore demonstrating that the hydrofluorination of ynamides provides a general, straightforward, and user-friendly approach to bioisosteres of ureas, potent building blocks for biological studies and medicinal chemistry.

Hybrid fullerene conjugates as vectors for DNA cell-delivery

C60-PEI and C60-PEG-PEI as efficient binders of dsDNA, with good transfection up to 25%, high cytocompatibility and cell proliferation up to 200%.

Supramolecular self-assemblies as functional nanomaterials

In this review, we survey the diversity of structures and functions which are encountered in advanced self-assembled nanomaterials. We highlight their flourishing implementations in three active domains of applications: biomedical sciences, information technologies, and environmental sciences. Our main objective is to provide the reader with a concise and straightforward entry to this broad field by selecting the most recent and important research articles, supported by some more comprehensive reviews to introduce each topic. Overall, this compilation illustrates how, based on the rules of supramolecular chemistry, the bottom-up approach to design functional objects at the nanoscale is currently producing highly sophisticated materials oriented towards a growing number of applications with high societal impact.

Inkjet-compatible single-component polydiacetylene precursors for thermochromic paper sensors

Inkjet-printable diacetylene (DA) supramolecules, which can be dispersed in water without using additional surfactants, have been developed. The supramolecules are generated from DA monomers that contain bisurea groups, which are capable of forming hydrogen-bonding networks, and hydrophilic oligoethylene oxide moieties. Because of suitable size distribution and stability characteristics, the single DA component ink can be readily transferred to paper substrates by utilizing a common office inkjet printer. UV irradiation of the DA-printed paper results in generation of blue-colored polydiacetylene (PDA) images, which show reversible thermochromic transitions in specific temperature ranges. Inkjet-printed PDAs, in the format of a two-dimensional (2D) quick response (QR) code on a real parking ticket, serve as a dual anticounterfeiting system that combines easy decoding of the QR code and colorimetric PDA reversibility for validating the authenticity of the tickets. This single-component ink system has great potential for use in paper-based devices, temperature sensors, and anticounterfeiting barcodes.

Antifungal vanillin-imino-chitosan biodynameric films

Vanillin-chitosan biodynamers have been prepared and structure-morphology correlations revealed the pathway of progressive incorporation of the aldehyde onto chitosan backbones. Such dynamic biopolymers or biodynamers, generated from reversibly interacting components, offer the possibility to address the dynamic covalent behaviour of the reversible imine-bond formation/hydrolysis equilibria between vanillin and chitosan polymeric backbones. The reaction takes place with very low conversion in acidic aqueous solutions (7-12%), but the imine bond formation is amazingly improved (∼80%) when the reaction takes place while solution-solid state transition and solid state phase-organization events occur. The chitosan-vanillin biopolymeric films described here present interesting Candida albicans antifungal activity compared with other common bacterial strands, which suggests the implementation of these biocompatible materials as thin layer protecting systems for medical devices.