Diseases
induced by bacterial infections increasingly threaten
the health of people all over the world; thus, it is urgent and significant
to early diagnose and effectively eliminate infections to save people’s
lives. To this end, we synthesized an intelligent hydrogel that integrated in situ visualized diagnosis and photothermal therapy of
bacterial infections. By simply and subtly incorporating pH-sensitive
bromothymol blue (BTB) and near-infrared (NIR)-absorbing conjugated
polymer (termed as PTDBD) into thermosensitive chitosan (CS)-based
hydrogel, the synthesized BTB/PTDBD/CS hydrogel can diagnose the acidic
microenvironment of Staphylococcus aureus (S. aureus) biofilm and infected
wounds by showing visualized color change. After rapid diagnosis,
the hydrogel can immediately treat the infection site by local hyperthermia
under irradiation of NIR laser (808 nm) and even the stubborn biofilm
that is difficult to eradicate. Since the dominating antibacterial
mechanism is hyperthermia, the hybrid hydrogel shows broad-spectrum
antibacterial activity against Gram-positive, Gram-negative, and drug-resistant
bacteria. In addition, it has low cytotoxicity to normal cells and
no effect on the main organs of mice. It paves a brand new avenue
to develop smart and facile diagnosis and a treatment platform for
bacterial infections.
Full-length hammerhead ribozymes were subjected to in vitro selection to identify variants that are allosterically regulated by theophylline in the presence of a physiologically relevant concentration of Mg(2+). The population of allosteric ribozymes resulting from 15 rounds of in vitro selection yielded variants with observed rate constants (k (obs)) as high as 8 min(-1) in the presence of theophylline and maximal k (obs) increases of up to 285-fold compared to rate constants measured in the absence of effector. The selected ribozymes have kinetic characteristics that are predicted to be sufficient for cellular gene control applications, but do not exhibit any activity in reporter gene assays. The inability of the engineered RNAs to control gene expression suggests that the in vitro and in vivo folding pathways of the RNAs are different. These results provide several key pieces of information that will aid in future efforts to engineer allosteric ribozymes for gene control applications.
A low-cost conducting polymer material polyaniline is developed as a solid-state redox mediator for decoupling the two half-reactions of water splitting in acidic media.
A unique in situ O2-emission assisted synthesis method was developed to prepare MoxC-based nanomaterials which exhibit outstanding HER catalytic performance.
The development of efficient electrocatalysts for hydrogen evolution reaction (HER) is of increasing importance in energy conversion schemes. The earth-abundant transition-metal phosphides, especially CoP and NiP, have emerged as promising catalysts for HER. We describe here the preparation and characterization of a hybrid catalyst of NiP nanosheets@CoP nanowires on a carbon cloth for the reaction. The heterostructure and synergistic effects of the NiP and CoP components result in an extremely low overpotential of 55 mV for achieving a catalytic current density of 10 mA cm, which is remarkable for transition-metal phosphide electrocatalysts. The synthetic procedure could be readily extended to related, heterostructured bimetallic sulfides or selenides for HER.
A novel NIR-absorbing and water-soluble conjugated polymer (PTDBD) for single-NIR-light induced synergetic photothermal/photodynamic therapy was developed.
Bacterial infections
induced by drug-resistant strains
have become
a global crisis. A membrane-disrupted mechanism is considered as an
effective way to kill bacteria with little chance to trigger drug
resistance. It is necessary to explore and develop new materials based
on the membrane-disrupted mechanism to combat bacterial resistance.
Here we report the design of organic nanoparticles based on a polymer
(PDCP) as highly effective inhibition and bactericidal reagents. The
PDCP is devised to have a hydrophobic skeleton and hydrophilic side
chain modified with protonated primary amines, which could self-assemble
to form organic nanoparticles (PDCP-NPs). By taking advantage of the
large surface to volume ratio of nanoparticles, the synthesized PDCP-NPs
have enriched positive charges and multiple membrane-binding sites.
Research results display that PDCP-NPs have highly potent antibacterial
activity in vitro and vivo, especially for Gram-negative bacteria
with low toxicity against mammalian cells. This work design will inspire
researchers to develop more membrane-disrupted bactericide and advance
the applications of organic nanoparticles in the antibacterial area.
The development of non-noble metal-based electrocatalysts for the hydrogen evolution reaction (HER) has attracted increasing attention over recent years. As a promising HER catalyst candidate, the preparation of molybdenum carbide requires high temperature for carbothermal reduction, which often causes nanoparticles sintering, leading to low exposed active sites. In this work, highly dispersed β-Mo 2 C nanoparticles of approximately 5 nm embedded in ordered mesoporous carbon (Mo 2 C@OMC) have been synergistically synthesized. During the synthesis process, the resol precursor for OMC template could serve as carbon source for the formation of Mo 2 C and mitigate the sintering of Mo 2 C nanoparticles. The resultant well-defined Mo 2 C possesses highly exposed active sites of approximately 26.5% and exhibits an excellent performance for the HER in both acidic and alkaline solutions. The synthetic procedure developed in this study may be extended to fabricate other metal carbide@ OMC nanocomposites for the HER and other electrocatalytic applications.
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