Curing cancer has been one of the greatest conundrums in the modern medical field. To reduce side-effects associated with the traditional cancer therapy such as radiotherapy and chemotherapy, photothermal therapy (PTT) has been recognized as one of the most promising treatments for cancer over recent years. PTT relies on ablation agents such as nanomaterials with a photothermal effect, for converting light into heat. In this way, elevated temperature could kill cancer cells while avoiding significant side effects on normal cells. This theory works because normal cells have a higher heat tolerance than cancer cells. Thus, nanomaterials with photothermal effects have attracted enormous attention due to their selectivity and non-invasive attributes. This review article summarizes the current status of employing nanomaterials with photothermal effects for anti-cancer treatment. Mechanisms of the photothermal effect and various factors affecting photothermal performance will be discussed. Efficient and selective PTT is believed to play an increasingly prominent role in cancer treatment. Moreover, merging PTT with other methods of cancer therapies is also discussed as a future trend.
Antibacterial metal ions, such as Ag+, Zn2+ and Cu2+, have been extensively used in medical implants and devices due to their strong broad spectrum of antibacterial activity. However, it is still a controversial issue as to whether they can show the desired antibacterial activity while being toxic to mammalian cells. It is very important to balance their antibacterial effectiveness with minimal damage to mammalian cells. Toward this end, this study is to identify the suitable concentrations of these three ions at which they can effectively kill two types of clinically relevant bacteria (Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli)) but show no obvious cytotoxicity on fibroblasts. Such concentration ranges are found to be 2.5 × 10−7 M–10−6 M, 10−5 M–10−4 M, and 10−5 M–10−4 M for Ag+, Zn2+, and Cu2+, respectively. Investigation of their antibacterial mechanism shows that these three metal ions all show antibacterial property through a mechanism of damaging bacterial cell membranes by the generation of reactive oxygen species but surprisingly preserving the integrity of bacterial genomic DNA. The encouraging results indicate that antibacterial metal ions with controlled concentrations can bring considerable benefits to biomedical applications.
Linear alkyl benzenes (LAB) are global chemicals that are produced by acid-catalyzed reactions that involve the formation of carbocationic intermediates. One outcome of the acid-based catalysis is that 1-phenylalkanes cannot be produced. Herein, it is reported that [Rh(μ-OAc)(η-CH)] catalyzes production of 1-phenyl substituted alkene products via oxidative arene vinylation. Since C═C bonds can be used for many chemical transformations, the formation of unsaturated products provides a potential advantage over current processes that produce saturated alkyl arenes. Conditions that provide up to a 10:1 linear:branched ratio have been achieved, and catalytic turnovers >1470 have been demonstrated. In addition, electron-deficient and electron-rich substituted benzenes are successfully alkylated. The Rh catalysis provides ortho:meta:para selectivity that is opposite to traditional acid-based catalysis.
of catalytic benzene alkenylation using different diimine
ligated Rh(I) acetate complexes and Cu(OAc)2 as the oxidant
revealed statistically identical results in terms of activity and
product selectivity. Under ethylene pressure, two representative diimine
ligated rhodium(I) acetate complexes were demonstrated to exchange
the diimine ligand with ethylene rapidly to form [Rh(μ-OAc)(η2-C2H4)2]2 and
free diimine. Thus, it was concluded that diimine ligands are not
likely coordinated to the active Rh catalysts under catalytic conditions.
At 150 °C under catalytic conditions using commercial Cu(OAc)2 as the oxidant, [Rh(μ-OAc)(η2-C2H4)2]2 undergoes rapid decomposition
to form catalytically inactive and insoluble Rh species, followed
by gradual dissolution of the insoluble Rh to form the soluble Rh,
which is active for styrene production. Thus, the observed induction
period under some conditions is likely due to the formation of insoluble
Rh (rapid), followed by redissolution of the Rh (slow). The Rh decomposition
process can be suppressed and the catalytically active Rh species
maintained by using soluble Cu(II) oxidants or Cu(OAc)2 that has been preheated. In such cases, an induction period is not
Reactive oxygen species (ROS) can be used to kill bacterial cells, and thus the selective generation of ROS from material surfaces is an emerging direction in antibacterial material discovery. We found the polarization of piezoelectric ceramic causes the two sides of the disk to become positively and negatively charged, which translate into cathode and anode surfaces in an aqueous solution. Because of the microelectrolysis of water, ROS are preferentially formed on the cathode surface. Consequently, the bacteria are selectively killed on the cathode surface. However, the cell experiment suggested that the level of ROS is safe for normal mammalian cells.
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