Polydiacetylene Research Articles

Light-induced transformation of a supramolecular gel to a stronger covalent polymeric gel.

A polymerizable diacetylene gelator, containing urea and urethane groups, that congeals various non-polar solvents was synthesized. The gelator molecules self-assemble forming non-covalent polymers through intermolecular hydrogen bonding, as evidenced from FT-IR and concentration-dependent 1H NMR spectroscopy. The self-assembly positions the diyne units of adjacent molecules at proximity and in a geometry suitable for their topochemical polymerization. UV irradiation of the gel resulted in topochemical polymerization, transforming the non-covalent polymer to a covalent polymer, in situ, in the gel state. The polymerization was confirmed by characterizing the polydiacetylene (PDA) using UV-Vis and Raman spectroscopy. Time-dependent rheological studies revealed gradual strengthening of the gel with the duration of irradiation, suggesting that the degree of polymerization increases with the duration of irradiation. The PDA formed is a semiconductor, which might be useful for various applications.

Colorimetric aptasensing of microcystin-LR using DNA-conjugated polydiacetylene.

Polydiacetylene (PDA) holds promise as a versatile material for biosensing applications due to its unique optical properties and self-assembly capabilities. In this study, we developed a colorimetric detection biosensor system utilizing PDA and aptamer for the detection of microcystin-LR (MC-LR), a potent hepatotoxin found in cyanobacteria-contaminated environments. The biosensor was constructed by immobilizing MC-LR-specific aptamer on magnetic beads, where the aptamer was hybridized with a urease-labelled complementary DNA (cDNA-urease). Upon binding MC-LR, the aptamer undergoes a conformational change to release cDNA-urease. The released cDNA-urease is subsequently captured by PDA bearing a single-stranded DNA (ssDNA). The enzymatic reaction triggers a distinctive color transition of PDA from blue to red. The results demonstrate exceptional sensitivity, with a linear detection range of 5-100ng/mL and a limit of detection as low as 1ng/mL. The practicability of the colorimetric method was demonstrated by detecting different levels of MC-LR in spiked water samples. The recoveries ranged from 77.3 to 102% and the color change, visible to the naked eye, underscores the practical utility for on-site applications. Selectivity for MC-LR over other microcystin variants (MC-RR and MC-YR) was confirmed. The colorimetric detection platform capitalizes on the properties of PDA and nucleic acid, offering a robust method for detecting small molecules with potential applications in environmental monitoring and public health.

A polydiacetylene (PDA)-based colorimetric sensor for on-site cyanide anion monitoring integrated with a lateral flow assay platform

An advanced sensing platform for the on-site and real-time monitoring of cyanide (CN−) pollution was developed, addressing the key challenges of enhancing the selectivity and sensitivity, whilst simplifying the sensing process. This platform features a novel colorimetric sensor (PDA-BMN) created by incorporating a receptor for CN− recognition within a polydiacetylene (PDA) conjugated polymer system. The interaction of CN− with the receptor distorted the π-conjugated backbone, causing a distinct color change from blue to orange, with a limit of detection (LOD) of 0.55 µM, thereby highlighting its high sensitivity. The PDA-BMN system was integrated into a lateral flow assay (LFA) strip to facilitate on-site monitoring. The LFA strip was strategically designed with a partially pressed zone to reduce the fluid flow rate, enhance the reaction time, and increase the probability of interaction with the PDA-BMN sensor. This innovation resulted in a significant colorimetric transition, enabling the rapid and sensitive detection of CN− without the requirement for analytical instruments. This study demonstrates the effectiveness of combining PDA and LFA systems for real-time environmental monitoring, offering a robust, efficient, and user-friendly solution for detecting CN− pollution.

Exploring the Origins of Low-Temperature Thermochromism in Polydiacetylenes.

This review article delves into the intriguing phenomenon of low-temperature thermochromism, whereby materials change color in response to temperature variations, with a particular focus on its applications in temperature-sensitive fields like medical storage. By closely examining thermochromic materials, this article highlights their potential to offer innovative solutions for monitoring and preserving thermolabile products that require strict temperature control. This leads to a special emphasis on polydiacetylenes (PDAs), a class of conjugated polymers with unique low-temperature thermochromic properties, positioning them as promising candidates for reliable temperature indicators. This article then explores the underlying mechanisms for fine-tuning the thermochromic behavior of PDAs, particularly discussing recent advancements in PDA design, such as structural alterations of monomers to achieve low-temperature thermochromism. These modifications, influenced by factors like side-chain length, hydrogen-bonding interactions, and the use of copolymers, are intended to result in irreversible color transitions at specific low temperatures, which is crucial to maintaining the integrity of thermally sensitive products. Finally, this article discusses the potential applications of PDAs as thermochromic sensors in tissue biobanking, where their ability to provide visual indications of temperature fluctuations could significantly enhance the monitoring and management of biological samples.

Non‐Uniform Electric Field Manipulation of Chromogenic Peptide Amphiphile Assemblies

This work investigates the influence of dielectrophoretic forces on the structural features and the resulting aggregates of a chromogenic model system, peptide‐diacetylene (D3GV‐DA) amphiphiles. Here, we systematically investigate how non‐uniform electric fields impact the (i) peptide‐directed supramolecular assembly stage and (ii) topochemical photopolymerization stage of polydiacetylenes (PDAs) in a quadrupole‐based dielectrophoresis (DEP) device, as well as the (iii) manipulation of D3GV‐DA aggregates in a light‐induced DEP (LiDEP) platform. The conformation‐dependent chromatic phases of peptide‐PDAs are utilized to probe the chain‐level effect of DEP exposure after the supramolecular assembly or after the topochemical photopolymerization stage. Steady‐state spectroscopic and microscopy analyses show that structural features such as the chirality and morphologies of peptidic 1‐D nanoassemblies are mostly conserved upon DEP exposure, but applying mild, non‐uniform fields at the self‐assembly stage is sufficient for fine‐tuning the chromatic phase ratio in peptide‐PDAs and manipulating their aggregates via LiDEP. Overall, this work provides insights into how non‐uniform electric fields offer a controllable approach to fine‐tune or preserve the molecularly preset assembly order of DEP‐responsive supramolecular or biopolymeric assemblies, as well as manipulate their aggregates using light projections, which have future implications for the precision fabrication of macromolecular systems with hierarchical structure‐dependent function.

Colorimetric sensing of fatty acids in organic solvents using polydiacetylene-based nanocomposites

Colorimetric detection of long chain fatty acids by polydiacetylenes (PDAs)-based sensors is quite a challenge, mainly due to their relatively low solubility in aqueous media. In this study, we developed PDA/Zn2+/ZnO nanocomposites in various organic solvents for detecting fatty acids. Oleic acid and steric acid were used as representatives of fatty acids with bent and linear structures, respectively. The nanocomposites dispersed in ethanol exhibited blue-to-red color transition upon increasing the concentration of oleic acid. The use of other solvents including 1-butanol, 1-hexanol, 1-octanol, 1,4-dioxane, hexane, octane and toluene affected the sensitivity of nanocomposites. Furthermore, incorporating cetyltrimethylammonium bromide (CTAB) into the structure of the nanocomposites resulted in a systematic increase of sensitivity. The use of organic solvents simplified the method and allowed direct sensing of the fatty acids. Paper-based sensor was fabricated and utilized as a mobile test kit. This class of colorimetric sensors can also distinguish the bent and linear structures of fatty acids. Our study extends the utilization of PDA-based materials as colorimetric sensors of fatty acids in food industries.

Polydiacetylene Liposome-Based Dual-Output Optical Sensor for ppb Level Detection of Dopamine in Solution and Solid Phases.

Dopamine (DA), a neurotransmitter, plays a crucial role in regulating motor functions and emotions and can serve as a marker for several diseases. In this study, we report a highly sensitive polydiacetylenes (PDA)-based dual-output sensor for dopamine detection in both solution and solid phases that was developed by modifying PDA liposomes with boronic acid groups at the termini. This sensor exploits the high affinity between the catechol residue of dopamine and the -B(OH)2 group of the PDA-based probe (PDA-PhBA) to form boronate ester bonds, causing a stress-induced blue-to-red color change along with a steady increase in fluorescence response at λmax 622 nm. The PDA-PhBA-based sensor displays high sensitivity toward dopamine with low limit of detection of 6.2 ppb in colorimetric analysis and 0.6 ppb in fluorimetric measurements, demonstrating its dual optical output ability. The sensor works well for adrenaline, another catecholamine, with similar efficacy. Its practical applicability was validated by the successful recovery of trace level dopamine in blood serum and real water samples. Additionally, immobilizing PDA-PhBA liposomes in sodium alginate produced PDA beads for the solid-phase detection of dopamine with an limit of detection (LOD) of 59 nM (9.0 ppb) in colorimetric detection using a smartphone for capturing images and ImageJ software for analysis.

A single-particle mechanofluorescent sensor

Monitoring mechanical stresses in microchannels is challenging. Herein, we report the development of a mechanofluorescence sensor system featuring a fluorogenic single polydiacetylene (PDA) particle, fabricated using a co-flow microfluidic method. We construct a stenotic vessel-mimicking capillary channel, in which the hydrodynamically captured PDA particle is subjected to controlled fluid flows. Fluorescence responses of the PDA particle are directly monitored in real time using fluorescent microscopy. The PDA particle displays significant nonlinear fluorescence emissions influenced by fluid viscosity and the presence of nanoparticles and biomolecules in the fluid. This nonlinear response is likely attributed to the torsion energy along the PDA’s main chain backbone. Computational fluid dynamic simulations indicate that the complete blue-to-red transition necessitates ~307 μJ, aligning with prior research. We believe this study offers a unique advantage for simulating specific problematic regions of the human body in an in vitro environment, potentially paving the way for future exploration of difficult-to-access areas within the body.

Construction and investigation of all-in-one microneedles complexed with functionalized polydiacetylene liposomes for improved in situ detection sensitivity

Polydiacetylene (PDA) liposomes have been widely applied for detection due to their distinctive optical properties. However, the liquid phase in which PDA liposomes are dispersed generates several drawbacks, for instance, instability, compromise of detection sensitivity induced by dilution, and separation of target sampling and detection, making it inconvenient for application. In this paper, various functionalized PDA liposomes for detecting target were prepared, which were also immobilized into swelling microneedles to construct a solid-phase detection system. The PDA liposomes-complexed microneedles (PDA/MNs) enable the integration of target sampling and detection in one platform. The effects of the dispersing matrix phase on the detection sensitivity of PDA liposomes were systematically investigated from both environmental and chemical perspectives. PDA/MNs exhibited higher sensitivity than their counterparts in liquid phase. PDA/MNs were optimized and validated for lead ion (Pb2+) and sialic acid (SA) detections. For Pb2+ detection, the limit of detection (LOD) of the PDA/MNs was 13.7 μM and 2.5 times lower than the liquid phase. For SA detection, the LOD of the PDA/MNs was 0.83 μM and 1.7 times lower than the liquid phase. The results suggested that such PDA/MNs were validated to provide a label-free, stable, sensitive, and convenient tool in an all-in-one manner for physiologic target detection.

A novel polydiacetylene-functionalized fibrinogen paper-based biosensor for on-spot and rapid detection of Staphylococcus aureus

Staphylococcus aureus contamination continues to be a harmful foodborne pathogen threatening of human health, and there is a growing need for rapid detection technologies. This study proposed a novel paper biosensor based on a polydiacetylene (PDA) polymer functionalized fibrinogen (Fg) for the detection of S. aureus in food sources. The fluorophore was developed based on the high binding ability of fibrinogen-binding proteins on the surface of S. aureus. This binding caused twisting in the PDA backbone, leading to changes in chromatic and fluorescent. The detection limit of this method was 50.1 CFU/mL for S. aureus-contaminated foodstuffs and 65.0 CFU/mL for the pure S. aureus culture, and the novelty came from its rapidity and selectivity for S. aureus compared to other foodborne bacteria. In summary, the present work provides a rapid detection method for S. aureus detection, which will help in addressing food safety-related issues.

Pressure-induced phase transition and solid-state polymerization of bis(trimethylsilyl)-substituted diacetylene (BTMSDA)

Solid-state topochemical polymerization (SSTP) reactions of diacetylenes (DAs) have garnered significant attention due to their crucial role in the synthesis and development of polydiacetylenes (PDAs). However, the SSTP reaction of bis(trimethylsilyl)-substituted diacetylene (BTMSDA) has not been reported until now due to its molecular stacking parameters seriously deviating from the conditions required for the SSTP reaction. To explore the possibility of the SSTP reaction of BTMSDA under high pressure, the structural evolution of BTMSDA in the range of 0∼12 GPa was investigated using diamond anvil cells combined with in situ Raman and infrared spectroscopy techniques. During compression, BTMSDA initially underwent a phase transition from DA-Ⅰ to DA-Ⅱ around 1.2 GPa. Subsequently, BTMSDA simultaneously experienced an SSTP reaction and another phase transition around 6.5 GPa, resulting in an uneven blue mixture consisting of the PDA-blue phase of Poly-BTMSDA and the DA-Ⅲ phase of BTMSDA. Upon decompression, the uneven blue mixture transformed into an uneven red mixture comprising the PDA-red phase of Poly-BTMSDA and the DA-Ⅰ phase of BTMSDA. Analysis reveals that the phase transitions were reversible, whereas the SSTP reaction was irreversible. Moreover, the first phase transition played a pivotal role in facilitating the SSTP reaction, while the second phase transition exhibited a competitive relationship with the SSTP reaction. This study not only deepens our understanding of the physicochemical properties of BTMSDA but also demonstrates the SSTP reaction of BTMSDA under high pressure.

A highly sensitive fluorescence biosensor for aflatoxins B1 detection based on polydiacetylene liposomes combined with exonuclease III-assisted recycling amplification.

Afluorescence biosensor for determination of aflatoxin B1 (AFB1)based on polydiacetylene (PDA) liposomes and exonuclease III (EXO III)-assisted recycling amplification was developed. The AFB1 aptamer partially hybridizes with complementary DNA (cDNA), which is released upon recognition of AFB1 by the aptamer. Subsequently, the cDNA hybridizes with hairpin H to form double-stranded DNA that undergoes digestion by EXO III, resulting in the cyclic release of cDNA and generation of capture DNA for further reaction. The capture DNA then hybridizes with probe modified on PDA liposomes, leading to aggregation of liposomes and subsequent fluorescence production. This strategy exhibited a limit of detection of 0.18 ng/mL within the linear range 1-100 ng/mL with adetermination coefficient > 0.99. The recovery ranged from 92.81 to 106.45%, with relative standard deviations (RSD) between 1.73 and 4.26%, for corn, brown rice, peanut butter, and wheatsamples. The stability, accuracy, and specificity of the method demonstrated the applicability for realsampleanalysis.

Optical Laser Tweezer‐Directed Single Particle Solvatochromism of Conjugated Polydiacetylene

Solvatochromism plays a pivotal role in various scientific and technological fields including those that explore molecular interactions, sensing technologies, and organic electronics. Notably, despite their ease of manipulation, direct visualization, and potential for single particle‐based sensing, micro‐sized solid particles have been the focus of a surprisingly low number of solvatochromism investigations. In this study, polydiacetylene (PDA) particles are synthesized and their solvatochromism is investigated at the single particle level using optical laser tweezers‐based methods. The findings reveal that unpolymerized monomers within PDA particles at the water/n‐decane interface undergo dissolution in the n‐decane phase to form internal voids in the particles. This phenomenon leads to structural deformation of the PDA which triggers a solvatochromic response. Studies that integrate this phenomenon with established particle‐based methodologies should provide deeper insights into diverse chromism behaviors and potential applications of solvatochromic materials.

Mechanical Properties of Polydiacetylene Multilayers Studied by AFM Force Spectroscopy.

The blue-to-red chromatic phase transition of polydiacetylene (PDA) is accompanied by the twist and rearrangement of its side chains, which results in shortening of the conjugation length in the backbone. However, how these morphological changes affect its mechanical properties remains elusive. In this work, force spectroscopy mapping by atomic force microscopy was employed to quantify mechanical parameters of PDA thin films such as breakthrough force and Young's modulus at the monomer, blue, and red phases during the chromatic transition. We found that the breakthrough force increased by 113% and Young's modulus decreased by 21% during the blue-to-red transition, highlighting that the subtle change in the side-chain configuration has a dramatic impact on its mechanical properties.

A Color-Detectable Vitamin C Controlled-Release System Fabricated Using Electrospinning.

This study develops a vitamin C controlled-release system, trackable via color changes as a function of vitamin C release. The system is composed of coaxial microfibers prepared via coaxial electrospinning, with a core of poly(ethylene oxide) (PEO) incorporating vitamin C, and a shell composed of polycaprolactone (PCL) containing polydiacetylene (PDA) as the color-changing material. The shell thickness is controlled by adjusting the amount of PCL ejected during electrospinning, allowing regulation of the release rate of vitamin C. When vitamin C added to PEO penetrates the PCL layer, the color of PDA changes from blue to red, indicating a color change. The results of this study can be applied to devices that require immediate detection of vitamin C release levels.

Synthesis and characterization of fluorescent and thermochromic bifunctional composites: Polydiacetylene/zinc oxide quantum dots

Composites of polydiacetylenes (PDA) and zinc oxide (ZnO) find diverse applications in thermochromic inks, colorimetric sensors, and anticounterfeiting, albeit often with complex preparation methods, single functionality, and high color-changing temperature ranges. This study presents environmentally friendly aqueous composites exhibiting dual thermochromic and fluorescent properties, achieved by integrating ZnO quantum dots (QDs) with particle sizes below 10 nm with PDA. By varying the concentration ratio of ZnO QDs to PDA, the effects on fluorescence and thermochromic properties were systematically explored. The interaction between ZnO QDs and PDA interfaces causes alterations to the energy states in the conjugated π-orbital array within PDA molecules. In contrast to pure PDA solutions, the composite materials not only exhibit thermochromism but also fluorescence. Demonstratively, the composite was applied as functional ink or paste for writing, film production, and inkjet printing, maintaining robust thermochromic sensitivity and fluorescence properties in the resulting specimens. This methodology imparts excellent multifunctionality to composite materials, enhancing and broadening their application potential.

Cellulose-based intelligent packaging films with antibacterial, UV-blocking, and biodegradable properties for shrimp freshness monitoring

The development of sustainable and functional packaging materials has become a very promising way to reduce pollution from traditional plastics. To address the shortcomings of natural materials with single function, poor antimicrobial and mechanical properties, and to develop more competitive green food packaging, a sodium carboxymethyl cellulose based multifunctional packaging film interspersed with wheat straw cellulose fibers (CF) and cellulose nanofibers (CNF) was proposed in this study, where CF and CNF increased the surface area of the film and loading capacity of the functional materials at the micrometer and nanometer levels, respectively. A biodegradable supramolecular polymer, polydiacetylene (PDA), was introduced into the film. Then, ZnO nanoparticles and PDA carboxylate head group coordination self-assembly strategy was utilized to build a PDA/Zn2+ intercalation composite structure, which was able to produce a highly sensitive specific response to biogenic amine and endowed the film with the ability of visual indication, as well as to effectively improve the film’s antimicrobial, ultraviolet light shielding, gas barrier, and water resistance properties. Moreover, the dense structure enables the film to withstand more than 50 reciprocal folds of nearly 180°, far exceeding that of ordinary packaging paper (about 10 folds). Composite packaging film enabled effective quality retention and spoilage monitoring of high protein products, especially shrimp with high biogenic amine release. This study provides a valuable reference for the application of supramolecular polymers, such as PDA, in food packaging materials, and gives a diversified development idea for plastic alternative packaging and multifunctional food packaging.

High-Sensitive Spatiotemporal Distribution Imaging of Compression Stresses Based on Time-Evolutional Responsiveness.

Mechanoresponsive materials have been studied to visualize and measure stresses in various fields. However, the high-sensitive and spatiotemporal imaging remain a challenging issue. In particular, the time evolutional responsiveness is not easily integrated in mechanoresponsive materials. In the present study, high-sensitive spatiotemporal imaging of weak compression stresses is achieved by time-evolutional controlled diffusion processes using conjugated polymer, capsule, and sponge. Stimuli-responsive polydiacetylene (PDA) is coated inside a sponge. A mechanoresponsive capsule is set on the top face of the sponge. When compression stresses in the range of 6.67-533kPa are applied to the device, the blue color of PDA is changed to red by the diffusion of the interior liquid containing a guest polymer flowed out of the disrupted capsule. The applied strength (F/N), time (t/s), and impulse (F·t/N s) are visualized and quantified by the red-color intensity. When a guest metal ion is intercalated in the layered structure of PDA to tune the responsivity, the device visualizes the elapsed time (τ/min) after unloading the stresses. PDA, capsule, and sponge play the important roles to achieve the time evolutional responsiveness for the high-sensitive spatiotemporal distribution imaging through the controlled diffusion processes.

Mechanoresponsive diacetylenes and polydiacetylenes: novel polymerization and chromatic functions

Abstract This review focuses on recent advancements regarding mechanoresponsive functions of diacetylene (DA) and polydiacetylene (PDA). Their ability to undergo pronounced topochemical polymerization and chromatic behavior variations in response to external stimuli has marked them as a promising platform for chemo- and bio-sensing over the past few decades. Notably, major advances, showcasing selective and highly sensitive mechanoresponses along with their quantitative analysis, have been achieved in recent years. The categorization includes DAs undergoing pressure-controlled crystalline transitions and polymerization, as well as PDAs exhibiting mechanochromic or mechanofluorochromic transitions. Accordingly, this review covers molecular designs allowing mechanical activation for topochemical polymerization, nanostructured or hybridized PDAs for amplifying stimulus-optical response feedback, nanoscopic analytical tools for mechanochromism, and their potential applications in mechanochemical sensing and imaging.

A polydiacetylene (PDA) based dual-mode optical sensor for the ppb level selective detection of biogenic polyamines

Biogenic polyamines (BPAs), specifically spermine and spermidine, play vital roles in cellular physiology, influencing processes like cell growth and proliferation. Beyond their cellular implications, these amines serve as biomarkers for cancer and aging-related diseases. This study presents a dual-output optical sensor for BPAs using polydiacetylene (PDA). The sensor utilizes alendronate's phosphate groups as recognition units for BPAs in liquid and solid phases. Ammonium groups of BPAs interact with negatively charged alendronate-modified PDA (PDAPH) liposomes causing a color change from blue to red accompanied by a gradual increase in fluorescence output at λmax 622 nm. The sensor exhibits high sensitivity with low detection limits of 4.3 ppb and 5.1 ppb for spermine and spermidine in colorimetric analysis, and lower limits of 1.6 and 1.4 ppb in fluorimetric measurements respectively, demonstrating its dual output ability. PDAPH liposomes also respond to cadaverine and putrescine indicating the probe's ability to detect key BPAs. The sensor shows minimal responses to interfering species, confirming its selective affinity towards BPAs. Practical validation in real water, urine, and serum samples demonstrates the sensor's efficiency. Immobilization of PDAPH liposomes into sodium alginate results in the creation of PDA beads. These beads exhibit a discernible color change when exposed to BPA concentrations exceeding 0.3 μM with a sufficiently low detection limit of 11.7 ppb in the solid phase. These findings highlight the efficiency of the PDAPH liposome sensor for accurate and reliable biogenic polyamine detection.