6 research outputs found
Synthesis of Multifunctional Cationic Poly(<i>p</i>‑phenylenevinylene) for Selectively Killing Bacteria and Lysosome-Specific Imaging
In
this work, a cationic polymer was synthesized to bear quaternized <i>N</i>-methyl-imidazole groups in the side chains. Positively
charged PPV-M could selectively bind to Gram-negative and Gram-positive
bacteria over fungi and exhibit enhanced antibacterial activity with
the aid of white light because PPV-M could sensitize oxygen to generate
reactive oxygen species (ROS) that would damage bacteria. In addition,
green fluorescent and positively charged PPV-M has the ability to
enter mammalian cells and be specifically accumulated in lysosome.
Moreover, PPV-M could stay in live cells for a relatively long time,
which implies that PPV-M has the potential to be a long-term imaging
agent
DNA Hydrogel by Multicomponent Assembly for Encapsulation and Killing of Cells
In
this work, a new multifunctional assembled hydrogel was prepared
by incorporating gadolinium ions (Gd<sup>3+</sup>) with salmon-sperm
DNA and polythiophene derivative (PT-COOH) through chelation interactions.
Efficient energy transfer from PT-COOH to Gd<sup>3+</sup> ions takes
place followed by sensitization of oxygen molecule to generate reactive
oxygen species (ROS) under light irradiation. Cancer cells can be
encapsulated into the hydrogel in situ as the formation of hydrogel
followed by killing by the ROS. Integration of imaging modality with
therapeutic function within a single assembled hydrogel is therefore
anticipated to be a new and challenging design element for new hydrogel
materials
Synthesis of a Novel Quinoline Skeleton Introduced Cationic Polyfluorene Derivative for Multimodal Antimicrobial Application
A new functional polyfluorene derivative
containing quinoline skeleton and quarternary ammonium group (QAG)
modified side chains (PFPQ) was synthesized and characterized. The
multimodal antimicrobial effect toward Gram-negative E. coli was achieved by the dark toxicity resulting
from the quinoline skeleton, QAG, and light toxicity resulting from
reactive oxygen species (ROS) produced by the main backbone of PFPQ
under white light. The mechanism of interaction between PFPQ and bacteria
was also demonstrated. PFPQ bound to E. coli mainly through electrostatic interactions causing nearly 50% bacterial
death in the absence of light irradiation, and the huge capability
of PFPQ to generate ROS under white light opened another bactericidal
mode. The killing efficiency was more than 99% upon relatively mild
irradiation under white light (400–800 nm) with a light dose
of 18 J·cm<sup>–2</sup>. PFPQ with the incorporation of
quinoline into the backbones will provide a new versatile strategy
to achieve the multimodal antimicrobial effect to fight against resistant
bacteria
New Conjugated Polymers for Photoinduced Unwinding of DNA Supercoiling and Gene Regulation
Three cationic polythiophene derivatives (<b>P1</b>, <b>P2</b>, <b>P3</b>) were synthesized and characterized.
Under
white light irradiation (400–800 nm), they sensitize oxygen
molecule in the surrounding to generate reactive oxygen species (ROS)
that can efficiently unwind the supercoiled DNA in vitro. Further
study shows that this relaxation of the DNA supercoiling results in
the decrease of gene (pCX-EGFP plasmid) expression level. The ability
of these conjugated polymers for regulating gene expression will add
a new dimension to the function of conjugated polymers
Chemical Molecule-Induced Light-Activated System for Anticancer and Antifungal Activities
Except for chemotherapy, surgery, and radiotherapy, photodynamic
therapy (PDT) as new therapy modality is already in wide clinic use
for the treatment of various diseases. The major bottleneck of this
technique is the requirement of outer light source, which always limits
effective application of PDT to the lesions in deeper tissue. Here,
we first report a new modality for treating cancer and microbial infections,
which is activated by chemical molecules instead of outer light irradiation.
In this system, in situ bioluminescence of luminol can be absorbed
by a cationic oligoÂ(<i>p</i>-phenylene vinylene) (<b>OPV</b>) that acts as the photosensitizer through bioluminescence
resonance energy transfer (BRET) process. The excited <b>OPV</b> sensitizes oxygen molecule in the surroundings to produce reactive
oxygen species (ROS) that kill the adjacent cancer cells in vitro
and in vivo, and pathogenic microbes. By avoiding the use of light
irradiation, this work opens a new therapy modality to tumor and pathogen
infections
Electrochemiluminescence for Electric-Driven Antibacterial Therapeutics
The employment of physical light
sources in clinical photodynamic therapy (PDT) system endows it with
a crucial defect in the treatment of deeper tissue lesions due to
the limited penetration depth of light in biological tissues. In this
work, we constructed for the first time an electric driven luminous
system based on electrochemiluminescence (ECL) for killing pathogenic
bacteria, where ECL is used for the excitation of photosensitizer
instead of a physical light source to produce reactive oxygen species
(ROS). We named this new strategy as ECL-therapeutics. The mechanism
for the ECL-therapeutics is dependent on the perfect spectral overlap
and energy transfer from the ECL generated by luminol to photosensitizer,
cationic oligoÂ(<i>p</i>-phenylenevinylene) (OPV), to sensitize
the surrounding oxygen molecule into ROS. Furthermore, taking into
account the practical application of our ECL-therapeutics, we used
flexible hydrogel to replace the liquid system to develop hydrogel
antibacterial device. Because the chemical reaction is a slow process
in the hydrogel, the luminescence could last for more than 10 min
after only electrifying for five seconds. This unique persistent luminescence
characteristic with long afterglow life makes them suitable for persistent
antibacterial applications. Thus, stretchable and persistent hydrogel
devices are designed by integrating stretchable hydrogel, persistent
ECL and antibacterial function into hydrogel matrices. This novel
strategy avoids the employment of external light source, making it
simple, convenient and controllable, which exploits a new field for
ECL beyond sensors and also opens up a new model for PDT