Polydiacetylene Vesicles Acting as Colorimetric Sensor for the Detection of Plantaricin LD1 Purified From Lactobacillus Plantarum LD1

The interaction of antimicrobial peptides with membrane lipids plays a major role in numerous physiological processes. Bacteriocins are antimicrobial peptides known to kill target cells by pore formation and membrane disruption. In this study, polydiacetylene (PDA) vesicles were applied as artificial membrane for detection of plantaricin LD1 purified from Lactobacillus plantarum LD1. Plantaricin LD1 (200 µg/ml) was able to change the color of PDA vesicles from blue to red with colorimetric response CR % 30.26 ± 0.59. Nisin (200 µg/ml), used as control, also changed the color of the vesicles with CR % 50.56 ± 0.98 validating the membrane-acting nature of these bacteriocins. The PDA vesicles treated with nisin and plantaricin LD1 showed increased infrared absorbance at 1411.46 cm-1 and 1000-1150 cm-1 indicated the interaction of bacteriocins with phospholipids and fatty acids, respectively. Further, microscopic examination also suggested the disruption of bacteriocin-treated vesicles indicating the interaction of bacteriocins. These findings suggest that the PDA vesicles may be used as bio-mimetic sensor for the detection of bacteriocins produced by several probiotics in food and therapeutic applications.

Aptamer-Conjugated Polydiacetylene Colorimetric Paper Chip for the Detection of Bacillus thuringiensis Spores

A colorimetric polydiacetylene (PDA) paper strip sensor that can specifically recognize Bacillus thuringiensis (BT) HD-73 spores is described in this work. The target-specific aptamer was combined with PDA, and the aptamer-conjugated PDA vesicles were then coated on polyvinylidene fluoride (PVDF) paper strips by a simple solvent evaporation method. The PDA-aptamer paper strips can be used to detect the target without any pre-treatment. Using the paper strip, the presence of BT spores is directly observable by the naked eye based on the unique blue-to-red color transition of the PDA. Quantitative studies using the paper strip were also carried out by analyzing the color transitions of the PDA. The specificity of this PDA sensor was verified with a high concentration of Escherichia coli, and no discernable change was observed. The observable color change in the paper strip occurs in less than 1 h, and the limit of detection is 3 × 107 CFU/mL, much below the level harmful to humans. The PDA-based paper sensor, developed in this work, does not require a separate power or detection device, making the sensor strip highly transportable and suitable for spore analysis anytime and anywhere. Moreover, this paper sensor platform is easily fabricated, can be adapted to other targets, is highly portable, and is highly specific for the detection of BT spores.

Responsive Polydiacetylene Vesicles for Biosensing Microorganisms

Polydiacetylene (PDA) inserted in films or in vesicles have received increasing attention due to PDA property to undergo a blue-to-red colorimetric transition along with a change from non-fluorescent to fluorescent upon application of various stimuli. In this review paper, the principle of the detection of various microorganisms (bacteria: directly detected or detected through the emitted toxins or through their DNA, and viruses) and of antibacterial and antiviral peptides based on these responsive PDA vesicles are detailed. The obtained analytical performances, when vesicles are in suspension or immobilized, are given and compared to those of the responsive vesicles mainly based on the vesicle encapsulation method. Many future challenges are then discussed.

Janus-like Fe3O4/PDA vesicles with broadening microwave absorption bandwidth

Fe3O4/PDA vesicle Janus nanospheres were successfully synthesized, and they exhibited an ultra-wide effective band as wide as 11.6 GHz, covering 73% of the whole measured frequency range (2–18 GHz), and a strong absorption intensity as high as −50.0 dB due to the asymmetric polarization and magnetic coupling effect.

A 3D networked polydiacetylene sensor for enhanced sensitivity

Immobilization of polydiacetylene (PDA) vesicles on the surface of the modified carbon nanotube (CNT)-networked pillared structures afforded a 3D networked sensor system. A more than three order increase in the sensitivity was observed with the 3D networked sensor matrix in comparison with a conventional 2D PDA sensor system.

“Clickable” thiacalix[4]arene derivatives bearing polymerizable 1,3-butadiyne fragments: synthesis and incorporation into polydiacetylene vesicles

Thiacalix[4]arene-functionalized polydiacetylene (PDA) vesicles showed selective colorimetric response toward several lanthanide ions. This approach can be a good basis for lanthanide express analysis.

A polydiacetylene-based fluorescence assay for the measurement of lipid membrane affinity

Polydiacetylene (PDA) is a promising membrane-screening tool because lipid constituents can be incorporated into the PDA framework to form lipid/PDA vesicles used as lipid bilayers.

Sensitive naked-eye detection of Hg2+based on the aggregation and filtration of thymine functionalized vesicles caused by selective interaction between thymine and Hg2+

A sensitive and low-cost method based on rapid interaction between functionalized PDA vesicles and Hg2+for the naked-eye detection of Hg2+.