Scavenging of free radicals in gas-phase mainstream cigarette smoke by immobilized catalase at filter level

Biochar Nanozyme from Silkworm Excrement for Scavenging Vapor-Phase Free Radicals in Cigarette Smoke

Serious lung diseases and other health problems caused by tobacco consumption are becoming more and more prominent all over the world. Scavenging the excessive harmful free radicals in cigarette smoke is proven to be an effective method in reducing the above problems. Carbon-based nanozymes have been widely studied due to their ability of scavenging free radicals. Accordingly, the biochar derived from silkworm excrement was reported as a nanozyme with free radical scavenging ability. The biochar nanozyme calcination at 900 °C with better free radical scavenging abilities was loaded into commercial cigarette filters for the following free radical scavenging verification in tobacco smoke. Mouse model results reveal the lung tissue could be improved by the addition of biochar nanozyme. This work not only provides an effective approach to reduce the harm caused by tobacco but also provides potential applications to rationally realize low-cost, ease of production, and a wide variety of biochar sources.

Alendronate-Modified Nanoceria with Multiantioxidant Enzyme-Mimetic Activity for Reactive Oxygen Species/Reactive Nitrogen Species Scavenging from Cigarette Smoke

Highly toxic radicals including reactive oxygen species (ROS) and reactive nitrogen species (RNS) in cigarette smoke play an important role in oxidative damage of the lungs, which cannot be efficiently scavenged by current filter techniques. Herein, a novel alendronate-coated nanoceria (CeAL) nanozyme is explored for cigarette filter modification for ROS/RNS scavenging. The CeAL nanozyme with an adjustable oxidation state and high thermal stability exhibits an excellent superoxide dismutase (SOD)-like activity, hydroxyl radical elimination capacity, catalase-mimicking activity, and nitric oxide radical scavenging ability. These synergistic antioxidant abilities make the CeAL nanozyme a lucrative additive for cigarette filters. The filter incorporated with the CeAL nanozyme can efficiently scavenge ROS/RNS in the hot smoke generated by burned commercial cigarettes, resulting in reduction of oxidative stress-induced pulmonary injury and acute inflammation of mice. The developed CeAL nanozyme opens up new opportunities for cigarette filter modification to decrease the toxicity of cigarette smoke and expands the application fields of nanoceria.

Copper Tannic Acid Coordination Nanosheet: A Potent Nanozyme for Scavenging ROS from Cigarette Smoke

The global tobacco epidemic is still a devastating threat to public health. Toxic reactive oxygen species (ROS) in the cigarette smoke cannot be efficiently eliminated by currently available cigarette filters. The resultant oxidative stress causes severe lung injury and further diseases. To tackle this challenge, herein, a novel copper tannic acid coordination (CuTA) nanozyme is reported as a highly active and thermostable ROS scavenger. The CuTA nanozyme exhibits intrinsic superoxide dismutase-like activity, catalase-like activity, and hydroxyl radical elimination capacity. These synergistic antioxidant abilities make the CuTA nanozyme a promising candidate for the improvement of commercial cigarette filters. Mouse model results show that commercial cigarettes loaded with CuTA nanozyme efficiently scavenge ROS in the cigarette smoke, reduce oxidative stress-induced lung inflammation, and minimize the resultant acute lung injury. The developed CuTA nanozyme offers an efficient ROS scavenger with multiple antioxidant ability and opens up new opportunities for the modification of cigarette filters to reduce the toxic effects of cigarette smoke.

A Standardized Method for the Preparation of a Gas Phase Extract of Cigarette Smoke

The gas phase of cigarette smoke is important from the viewpoint of human health, because it can pass through alveolar epithelium and enter the circulation. There is no standard method for the preparation of a gas phase extract of cigarette smoke (CSE), although CSE is widely used for research instead of whole cigarette smoke. We have established a standard method for the preparation of CSE. One cigarette per trial is continuously combusted under a reduced pressure generated by an aspiration pump with a velocity of 1.050 L/min: the main stream of the smoke is passed through a Cambridge filter to remove tar, and subsequently, bubbled through a glass ball filter (pore size, 20-30 µm) into 15 mL of phosphate-buffered saline (PBS). To express the concentration of CSE, a virtual tar concentration is introduced, which is calculated assuming that tar trapped on the Cambridge filter is dissolved in the PBS. CSEs prepared from smaller numbers of cigarettes (original virtual tar concentration≤15 mg/mL) show similar concentration-response curves for cytotoxicity versus virtual tar concentrations. CSEs prepared from various brands of cigarettes and by different smoking regimes (continuous and puff smoking) show similar cytotoxic potency if the virtual tar concentrations are the same. In conclusion, using the standardized method for CSE preparation in combination with the virtual tar concentration, it becomes possible to simply and rapidly prepare standard CSEs with defined concentrations from any brand of cigarettes, which are toxicologically equivalent to CSE prepared by puff smoking.