Polydiacetylene Research Articles

Phase behavior of poly diacetylene mixed with a xanthene dye at air–water interface and onto solid support

ABSTRACTPolydiacetylene (PDA) and its derivatives exhibit interesting photophysical properties, specifically, visible colorimetric transformation which makes them promising candidates for applications in vast number of fields. PDA is obtained through photopolymerization of diacetylene monomers (DA) using UV-irradiation. UV-irradiation leads to the formation of meta stable nonfluorescent blue phase (blue polymer) which on further irradiation converted to stable auto fluorescent red phase (red polymer) with alternating triple and double bonds in ene-yen motif. Herein diacetylene monomers 10, 12-tricosadiynoic acid (TCDA) and amphiphilic octadecyl rhodamine B chloride (RhB18) has been used to prepare mixed Langmuir film. The presence of RhB18 at different molar ratio produces monolayer supramolecular structure as well as typical trilayer structure. Atomic force microscopy investigations gave visual evidence of the formation of trilayer. The mixed film containing TCDA mole fraction 0.8 produces monolayer and TCDA mole fraction 0.85 produces typical trilayer. Photopolymerization is possible only in the trilayer. Thus the phases of PDA can be tuned depending on the molar ratio of TCDA in the mixed film. This study demonstrates that the incorporation of dye RhB18 with diacetylene monomer TCDA provides a means for modulating the structure and chromatic features of PDA assemblies, giving rise to a new morphologies and unique optical properties. This may extend the field of application of PDA assemblies for sensing.

A polydiacetylenes-based sensor for the efficient detection of phospholipase D activity

Phospholipase D (PLD), as an enzyme that catalyses the hydrolysis of L-α-phosphatidylcholine to produce phosphatidic acid, plays an important role in regulating biological processes. In this work, polydiacetylenes (PDAs) bearing imidazolium as head group are reported for the efficient detection of PLD activity. Owing to the strong interaction between negatively charged phosphatidic acid and positively charged imidazolium moieties of PDAs, the PDAs were found to produce a colour transition from blue to red, and an increase in fluorescence. No obvious changes to PDAs were observed when PLD was absent in the reaction, or when the activity of PLD was inhibited by halopemide. The colour and fluorescence changes of PDAs are attributed to the generation of phosphatidic acid in the PLD-catalysed reaction. Furthermore, a paper sensor based on PDAs was constructed and exhibited convenient and sensitive detection of PLD activity.

Influences of bulky aromatic head group on morphology, structure and color-transition behaviors of polydiacetylene assemblies upon exposure to thermal and chemical stimuli

This contribution investigates the morphologies, packing structure and color-transition behaviors of polydiacetylene(PDA) assemblies prepared from 10,12-pentacosadiynoic acid (PCDA), 3-(pentacosa-10,12-diynamido)benzoic acid (PCDA-mBzA), and 6-(pentacosa-10,12-diynamido)-2-naphthoic acid (PCDA-NPA). This series of PDAs provides a systematic increase of head group size and overall inter- and intramolecular interactions within the assemblies. The increase of head group size affects the packing parameter of diacetylene(DA) monomers, causing morphological change from spherical vesicles to rod-like structures. X-ray diffraction reveals that the size of the head group also dictates molecular tilting angle within the lamellar structure of DA assemblies. The monocarboxylic poly(PCDA) exhibits irreversible thermochromism. The incorporation of aromatic head groups in poly(PCDA-mBzA) and poly(PCDA-NPA) enhances the overall interactions within assemblies, resulting in reversible thermochromism. Furthermore, the size of aromatic head groups strongly affects the response time and color reversibility in thin film. Interestingly, the sensitivity of PDAs to chemical stimuli including cationic surfactants and organic solvents is found to vary with type of head group. The poly(PCDA-mBzA) is more sensitive to cationic surfactants compared to the system of poly(PCDA-NPA). An opposite result is observed when organic solvents, tetrahydrofuran and pyridine, are used as chemical stimuli. Our study provides fundamental understanding about molecular factors affecting the self-assembling structure and color-transition behaviors of PDA materials.

Chromatic detection of Cs ions using polydiacetylene-based vesicles containing crown-ether-like ethylene glycol units

Radioactive 137Cs, which have a half-life of about 30.17 years, are a major source of nuclear pollution and should be detected and removed. For this purpose, a colorimetric, polydiacetylene (PDA) vesicle-based sensor was synthesized to detect Cs ions. The polymer vesicles consisted of commonly used 10,12-pentacosadiynoic acid (PCDA) and its derivatives. One of the derivatives that contained tetraethylene glycol (TEG) units at the end of the PCDA side chain, and thus it acted as a chelating agent that surrounded the Cs ion like a crown ether. As a result, the main chain of the PDA was distorted by the chelation of TEG and Cs ions, resulting in a blue-red color change. To provide selectivity to the PDA vesicles, another derivative was incorporated to the PDA vesicles with controlled amount, which was not responsive to alkali metal ions. The changes in the colorimetric response of the vesicles were not observed in the presence of other alkali metal ions such as Na, K, and Rb ions, indicating that the TEG units fitted well in size with the ionic radius of the Cs ion, resulting in high selectivity. Solid-state PDA film was also fabricated to provide selective detection of Cs ions.

Evaluating the effect of the surface morphology on the colorimetric sensitivity of poly-vinyl-pyrrolidone polydiacetylene composites

In this paper, we report the generation of Poly-vinyl-pyrrolidone (PVP) microfibers doped with two types of polydiacetylene (PDA): 10, 12-tricosadyinoic acid (TCDA) and 10,12-pentacosadiynoic acid (PCDA). The colorimetric transition behavior of the fibrous samples upon exposure to acetone stimulus is evaluated and compared to PVP layers doped with TCDA and PCDA. The quasi-instantaneous color shift of PVP-PDA microfibers and layers is quantitatively characterized by mean of UV-visible spectrometry and the colorimetric response (CR) is calculated from the absorption spectrums. The results show that PVP can be successfully used as a low cost host matrix for the development of PDA chemo and biosensors. In addition, the chemosensors exhibit sigmoidal behavior upon exposure to different acetone solutions and samples doped with TCDA present a higher sensitivity than samples doped with PCDA due to the length of their alkyl tail. Finally, the fibrous structure significantly enhance the sensors sensitivity by 1.6 times for TCDA samples and 10 times for PCDA samples highlighting the importance of the high surface to volume ratio provided by the electrospun fibers.

Creation of Centimeter-Sized 2 D Crystalline Film by Crystallization of Homopolymer in Solution.

The 2 D assembly of polymers to form free-standing and large crystalline films is quite appealing but very challenging. Although there have been some works using interface templates, reports of in situ assembly in solution are still rare. Herein, a simple strategy is developed for the creation of a free-standing and centimeter-sized 2 D crystalline polymer film through crystallization of an amphiphilic brush polydiacetylene (PDA) in solution. The film exhibits good shape memory, a low dielectric constant, and good carrier mobility. This strategy may be applied extensively to produce a variety of other macroscopic 2 D crystalline polymer films for applications in electronics, catalysis, and so on.

Pressure-Induced Transition of Bisamide-Substituted Diacetylene Crystals from Nonphotopolymerizable to Photopolymerizable State.

Mechanoresponsive diacetylenes (DAs) exhibiting a transition of crystalline orientation from light-inert to light-active state upon applied force are reported. Amide units are introduced to DAs where hydrogen bonding is utilized to control intermolecular interactions. Application of external pressure (2-150 MPa) to DAs results in an emergence of new crystal phases with changing the d-spacing which possibly reduces the reaction barrier. Accordingly, the dramatic crystalline transition from "perfectly off" to "on" state to undergo the light-induced topochemical polymerization of bulk DA crystals is obtained. Subsequent UV irradiation at a wavelength of 254 nm enables the polymerization of the pressed region, changing its color from white to blue which suggests the selective formation of polydiacetylene (PDA) polymorphs. In addition, by utilizing the mechanoresponsive crystallinity with low-enough activation pressure, a new strategy for PDA patterning is demonstrated based on the selective transfer of information by means of force to a DA film. This phenomenon can be applicable to a new nanoimprinting technique where no mechanical deformation of resist materials but phase transition is induced by the mold.

Tunable Stimuli‐Responsive Color‐Change Properties of Layered Organic Composites

AbstractStimuli‐responsive properties of soft materials originate from dynamic structure changes. Layered polydiacetylene (PDA) shows color‐change properties with the application of external stimuli, such as thermal and mechanical stresses. Layered organic materials possessing intercalation capabilities and dynamic properties have potentials for tuning their structures and properties by the intercalated guests. A variety of sensing and imaging devices can be developed by control of the stimuli responsivity. Here, the key structures, processes, and mechanisms for tuning the stimuli‐responsive color‐change properties of layered PDA are studied by in situ analyses with heating and cooling. The in situ analyses indicate that heating initiates thermal motion of the alkyl side chains of the PDA main chain in the host layers around 60 °C, regardless of the type of intercalated guests. Further heating induces torsion of the PDA main chain leading to color changes at different temperatures, depending on the types of the intercalated guest. Then, the layered structure is irreversibly deformed with lowering the crystallinity. The results indicate that the stimuli‐responsive color‐change properties are controlled by the rigidity of the layered structures consisting of the host layers and guests. The control strategy based on rigidity tuning can be applied to a variety of soft materials with stimuli responsivity.

Colorimetric polydiacetylene (PDA) liposome-based assay for rapid and simple detection of GST-fusion protein

The detection of proteins by gel electrophoresis and subsequent staining is the most commonly used method for protein analysis, but it requires considerable time and effort as well as denatured protein samples. In this study, we developed a polydiacetylene (PDA)-based colorimetric sensor that does not require any instrument, time-consuming processes, or protein denaturation steps. Specifically, to assess the expression of glutathione S-transferase (GST)-fusion recombinant protein utilizing the interactions between the enzyme GST and its substrate, glutathione (GSH), a terminal group of PDA monomers was modified with the GSH tripeptide. The diacetylene liposome containing the GSH-modified diacetylene monomer was polymerized upon UV irradiation at 254 nm, resulting in a blue PDA liposome. The terminal GSH moiety of the PDA liposome seemed to be perpendicular to the PDA backbone, enabling its easy interaction with the active site residues of GST in solution. Using the GSH-functionalized PDA sensor, we successfully detected GST and GST-human growth hormone (GST-hGH) by the blue-to-purple chromatic transitions. As this PDA colorimetric sensor is simple, rapid, and detectable by the naked eye without protein gel electrophoresis, this strategy is of great practical value as a point-of-care testing sensor for the expression of GST-fusion protein.

Immobilized Polydiacetylene Lipid Vesicles on Polydimethylsiloxane Micropillars as a Surfactin-Based Label-Free Bacterial Sensor Platform

Accurate detection and sensing of bacteria are becoming increasingly important not only in microbiology but in a variety of fields including medicine, food, public health, and environmental science. However, even new rapid methods are not convenient enough. Here, we describe a simple and efficient label-free bacterial detection system using the polydiacetylene (PDA) liposomes immobilized on the 3D polydimethylsiloxane (PDMS) micropillars. Our system utilizes the colorimetric response of amine functionalized PDA vesicles to surfactin, a bacterial cyclic lipopeptide commonly released by Gram-positive Bacillus species as an antibiotic. To improve the sensitivity of PDA vesicles to surfactin by increasing the number and surface area of immobilized vesicles, the PDA vesicles were immobilized on the micropillar structure to give a hierarchical 3D PDA vesicle structure. For the fabrication of the 3D micropillar structure, polydimethylsiloxane (PDMS) was used to overcome the limitations imposed by silicon-based fabrication. In contrast to the 2D-PDA-PDMS system, which could only hardly detect the presence of 500 µM surfactin, the 3D-PDA-PDMS system could efficiently detect the presence of 5 µM surfactin and the initial presence of 4 x 101 cells/ml of Bacillus subtilis NCIB3610, which actively produces surfactin. Furthermore, bacterial strains that are known to produce no surfactin, such as Staphylococcus aureus Newman, Escherichia coli DH5, and Pseudomonas aeruginosa PA14 were not detected by our system suggesting that the 3D-PDA-PDMS system is highly specific to surfactin but not to other chemicals produced by bacteria. Taken together, our results suggest that the 3D-PDA-PDMS system can sensitively and selectively be used for the high throughput detection and screening of biotechnologically important surfactin-producing bacterial strains.

Retarded evaporation-induced synthesis of lamellar block copolymer supramolecules for solvatochromic sensing

The responses of conventional solvatochromic sensors to stimuli are usually performed by generating changes in absorption and emission bands based on the polarity of solvents. However, there still remains a high risk of the overlapped bands for the solvents with similar polarities, resulting in a tough realization of the visual colorimetric differentiation. Here, we develop an innovative solvatochromic sensor in the form of film by self-assembly of block copolymer supramolecules. The produced sensor consists of alternating layers of two phases, in which one is polystyrene (PS) and the other is the combination of poly (4-vinylpyridine) (P4VP) and polydiacetylene (PDA). Owing to the fact that PDA is embedded into P4VP, the inherent protection of PDA by block copolymers is thus guaranteed in such lamellar structures. The specific organic solvents with a strong affinity to PS could merely penetrate into the supramolecular lamellae followed by interacting with thus-exposed PDA, leading to the realization of solvatochromism. By incorporating the heating-induced blue-to-red color transition (thermochromism) with solvatochromism of the sensor, a straightforward technique to realize the nonvisualization of an imprint followed by its revisualization is developed.

Comparative Analysis of Inhibition-Based and Indicator-Independent Colorimetric Assay for Screening of Bacteriocin-Producing Lactic Acid Bacteria.

Screening of bacteriocin-producing lactic acid bacteria (LAB) is an important aspect for the search of new/novel probiotic strains. Here, a vesicle-based colorimetric assay was compared with conventional inhibition-based antimicrobial assays using 54 isolates of LAB. All isolates demonstrated zone of growth inhibition ranging from 2.5 to 7.5mm against indicator strain, Micrococcus luteus MTCC106 using point inoculation method. Cell-free supernatant of the isolates showed zone of growth inhibition varying from 14.5 to 25mm using agar well diffusion assay. These isolates inhibited the growth of indicator strain by 89.56-98.65%. The antimicrobial activity present in cell-free supernatant of different isolates was found to be in the range of 10-160AUml- 1. The treatment of polydiacetylene (PDA) vesicles with cell-free supernatant of selected isolates led to blue-red color transition, and presence of protein band on tricine SDS-PAGE confirmed the presence of membrane-acting peptides, bacteriocins. The colorimetric responses (CR%) varied between 0 and 59%, and the assay was found to be more sensitive, faster, and reliable as compared to the other conventional indicator-based methods used. Therefore, the colorimetric assay may be specifically applied for screening of bacteriocin-producing LAB.

Solid-state polymerization of 1,4-bis(hexatriynyl)benzene derivatives

Two 1,4-bis(hexatriynyl)benzene derivatives with urethane groups, i.e., 10,10′-(1,4-phenylene)bis(5,7,9-decatriynyl N-(butoxycarbonylmethyl)carbamate) 1 and its perfluorophenylene derivative 2, were synthesized, and their solid-state photopolymerization was investigated. Upon UV irradiation, both of them showed excitonic absorption characteristic of polydiacetylene (PDA). In particular, 2 showed an absorption maximum at 743 nm, which was approximately 100 nm longer than that of conventional PDAs because of the effective conjugation between the polymer backbone and π-conjugated substituents. The conversion of 1 to the corresponding polymer was quite low. On the other hand, more than half of the hexatriynyl moieties of 2 were found to polymerize, indicating that most of the monomers were converted to the polymer upon prolonged UV irradiation.

Crystal polymorphs of 6-[(phenylcarbamoyl)oxy]hexa-2,4-diyn-1-yl isonicotinate.

The title compound, C19H14N2O4, was found to have two crystal polymorphs, in which the molecular structures of the diacetylenic compound are broadly similar. The main structural difference between the polymorphs concerns the intermolecular hydrogen-bonding motifs adopted, namely a one-dimensional zigzag polymer linked by N-H...N(py) (py is pyridine) interactions in polymorph I and a centrosymmetric dimeric motif formed by N-H...O=C interactions in polymorph II. The diacetylene cores of the molecules stack along the a and b axes in polymorphs I and II, respectively. It was found that only the molecular arrangement in polymorph II satisfies Baughman's criterion to afford polydiacetylenes (PDAs) by thermal annealing or irradiation with light. This predicted polymerization activity was confirmed by experiment.

High temperature thermochromic polydiacetylene supported on polyacrylonitrile nanofibers

Polydiacetylene (PDA) are polymers known to switch from blue to red when exposed to environmental stimuli. This paper reports on electrospun composite nanofibers of polyacrylonitrile (PAN) and a high temperature PDA. The effect of PAN on the thermal and thermochromic properties of the PDA was studied. PDA to PAN mass ratio in the composites was varied and an unusually high loading of 30 wt% PDA was achieved. Scanning and transmission electron microscopies (SEM, TEM) revealed a randomly-packed morphology of nanofibers with well dispersed PDA particles inside. Through differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA), the heat resistant PAN nanofibers were found to increase the reversible temperature range of the embedded PDA while also improving its thermal stability. Naked eye observations suggested that the composite thermochromic sensor can be reversed from temperatures around 200 °C - a big improvement from just 156 °C - while ultraviolet–visible spectroscopy (UV–vis) studies showed that there was a progressive deterioration of the conjugated PDA backbone which ultimately resulted in complete loss of reversibility and colorimetric character at 230 °C.

Tuning of the Topochemical Polymerization of Diacetylenes Based on an Odd/Even Effect of the Peripheral Alkyl Chain: Thermochromic Reversibility in a Thin Film and a Single-Component Ink for a Fountain Pen.

The topochemical polymerization of diacetylenes (DAs) is closely related to the length of their alkyl chain. DA monomers have two types of alkyl chain side groups: the inner alkyl chain and the outer alkyl chain, that is, the peripheral alkyl chain. Herein, we designed and synthesized a series of DA monomers that possess bis-amide linkages with different peripheral alkyl chains ( n = 6-9; DA1-DA4). The peripheral alkyl chain length of these DA monomers exhibits an odd/even effect on topochemical polymerization. The polymerization of DAs was achieved only when n is an odd number, whereas no polymerization occurred when n is an even number. The odd/even effect on the topochemical polymerization was also investigated using ab initio density functional theory calculations. The thermochromic reversibility of polydiacetylenes (PDAs) was investigated using UV-vis absorption spectroscopy at temperatures ranging from 20 to 60 °C. Monomer DA2 was used as a single-component ink solution in a fountain pen that can be transformed into thermochromic letters on conventional paper. Furthermore, a PDA-embedded polyethylene oxide film was included to monitor the thermochromic reversibility and was found to exhibit excellent thermochromic reversibility between 20 and 100 °C and stability, enabling storage for a few months without deformation. Finally, a green-colored patterned polymer film is readily obtained by a subtractive color (blue and yellow) mixing method and exhibits high thermochromic reversibility at temperatures between 20 and 100 °C.

Nanobiosensing of phenol and its derivatives in a Kraft synthetic black liquor

Phenol is an important raw material in the manufacturing industry, and it is found in industrial streams, both as a by-product and in wastewater flows. Due to their toxicity, the presence of phenol and its derivatives in water resources influences the quality of natural water, causing negative effects on human life. Thus, easily accessible measurement tools for phenol could be made available in rural communities where access to technology is limited. Sensors offer this opportunity, as they provide fast, reliable and easy use. In this study, a colorimetric nanobiosensor was developed based on polydiacetylene (PDA) liposomes, functionalized with Horseradish peroxidase (HRP).The recognition element was the HRP enzyme, immobilized at the surface of a cell-like nanostructure; biological interaction HRP-phenol was detected and the colorimetric PDA present in the liposome acted as a transducer element. After biological interaction, the polymer backbone is transformed from the blue to red phase; this colorimetric transition is observed visually and registered spectrometrically. The nanobiosensor was used to detect the phenol concentration in the 0.25 to 2 mM range in an industrial stream from the Kraft process, simulated under lab conditions. The response of the biosensor gives 7 % error in comparison with a spectrometric method.

A biomimetic nanoparticle-enabled toxoid vaccine against melittin

BackgroundMelittin, the main active peptide ingredient of bee venom, can cause severe cell membrane lysis due to its robust interaction with negatively charged phospholipids. So far, no effective anti-melittin vaccine has been developed to protect people from undesired melittin intoxication.MethodsHerein, we prepared a polydiacetylene (PDA) nanoparticle with cell membrane-mimic surface to complex melittin, forming an anti-melittin vaccine (PDA–melittin).ResultsPDA nanoparticles could effectively combine with melittin and neutralize its toxicity. PDA–melittin nanocomplex is demonstrated to enhance melittin uptake by DCs and stimulate strong melittin-specific immunity. Mice immunized with PDA–melittin nanocomplex showed higher survival rate after exposion to melittin than untreated mice.ConclusionThe PDA–melittin nanocomplex can efficiently and safely generate a specific immunity against melittin to protect body from melittin intoxication, providing a new method with potential clinical application for the treatment of melittin intoxication.

Order-Disorder transition of carboxyl terminated chains in polydiacetylenes vesicles probed by second harmonic generation and two-photon fluorescence

To understand and control the interfacial properties of polydiacetylenes (PDAs) vesicles with π-conjugated backbone is very important for their colorimetric sensing of chemical and biological targets. In this work, we adopted 10, 12-pentacosadiynoic acid (PCDA) as the model molecule to prepare PDAs vesicles in aqueous solution with different forms (from monomer to blue-to-purple-to-red phase) by controlling the UV irradiation dose. The variations of the interfacial conformation of PDAs vesicles during chromatic transitions were inspected by the adsorption behaviors of probe molecules (4-(4-diethylaminostyry)-1-methylpyridinium iodide, D289) on vesicle surface with surface-specific second harmonic generation (SHG) and zeta potential measurements. Resonant SHG signal from D289 adsorbed on vesicle surface attenuated sharply, and the adsorption free energy as well as the corresponding two-photon fluorescence signal decreased slightly in chromatic transitions. While, the change in the surface density of the adsorbed D289 molecules for PDAs vesicles with different forms was relatively small as estimated from zeta potential measurements. The attenuation of the SHG intensity was thus attributed to the overall order-disorder transition and the changed orientation of D289 molecules caused by the gradual distortion of carboxyl head group driven by backbone perturbation.

Polydiacetylene (PDA) as tool for the development of biosensors to apply in analytical field

Polydiacetylene (PDA) as tool for the development of biosensors to apply in analytical field