Fabrication of Helical Nanoribbon Polydiacetylene via Supramolecular Gelation: Circularly Polarized Luminescence and Novel Diagnostic Chiroptical Signals for Sensing

Abstract

Four kinds of commercially available diacetylene (DA) monomers with different chain length, diacetylene positions were fabricated into the organogels via mixing with a chaperone gelator, an amphiphilic l-histidine ester derivative LHC18 that can help the nongelator to form gels. Upon photo irradiation with a 254 nm UV light, the white gels underwent topochemical reaction and turned into red or blue gels, depending on the DA monomer structures. Through the gel formation, the molecular chirality of LHC18 can be transferred to the polydiacetylene (PDA) and helical nanoribbon structures were obtained. The blue gels showed a clear response to stimuli such as pH variation, heating, mechanical force and organic solvents, and turned into red gels. Interestingly, the blue gel showed strong supramolecular chirality, which could be turned off or changed into red phase CD signals. Such changes in chiroptical signals depended on the external heating and various organic solvents. In the case of heating, the blue gel changed into red one, which showed both strong CD signals and circularly polarized luminescence. In the case of organic solvents, although all the tested solvents made the blue gel to red, only some of them could keep the CD signals, thus providing additional sensing capacity of the PDA system. So far, the blue-to-red color change and the "fluorescence on" was widely used as colorimetric and fluorogenic diagnostic signals for PDA, here we showed an additional chiroptical diagnostic signal for a more precise sensing by using the helical PDA.

Highly Sensitive Polydiacetylene Ensembles for Biosensing and Bioimaging

“…For example, Zhong et al prepared chiral PDA Langmuir-Blodgett films with gemini type amphiphilic diacetylene derivatives (Zhong et al, 2010). In 2016, Chen et al found that chiral L-histidine ester derivative LHC18 amphiphiles could not only help the formation of diacetylene amphiphiles gels, but also endow PDA polymers with chiral properties (Chen et al, 2016).…”

“…PDA structures have been enriched from traditional films, micelles and vesicles to 3D-PDA structures, porous structures, hydrogels, macrocyclic structures, and single-layer nanosheets (Bang et al, 2016;Chae et al, 2016;Krishnan et al, 2016;Okaniwa et al, 2016;Jordan et al, 2017;Li et al, 2017a;Romera et al, 2017;Jeong et al, 2018;Takeuchi et al, 2018;Terada et al, 2018;Heo et al, 2019;Hu et al, 2019;Seo et al, 2019;Shin et al, 2020). Great progresses have also been made in the preparation of reversible and chiral PDA (Chen et al, 2016;He et al, 2020). PDA bioprobes based on these novel structures can further increase the sensitivity and reproducibility of detection, and their detection applications have thus been expanded to a wide range of biomolecules.…”

Co-assemblies of polydiacetylenes and metal ions for solvent sensing

“…Conjugated polymer-based sensors are sensitive to very minor perturbations due to amplification by a collective system response and therefore offer a remarkable advantage over small molecule-based sensors. [1][2][3][4][5][6] Polydiacetylenes (PDAs) are wellknown conjugated polymers. PDAs show stimuli-responsive blue-to-red color changes because the conformation of the conjugated backbone changes, which results in a change of the efficient conjugated length of the polymer chain.…”

A Polydiacetylene‐based Colorimetric Adenosine Triphosphate Sensor: A Molecular Protecting Approach

“…One meritorious feature of PDA is that it displays a brilliant color change (typically blue to red) in response to physical and chemical/biochemical stimuli 2–13 . Accordingly, this stimulus‐responsive property of PDA has been extensively used for the development of colorimetric sensors 2–30 …”