Significance: It is always a challenge to see the deposition of single PM _2.5 particles, the harmful inhalable aerosols in the polluted air, in alveolar region, and their invasion to the extrapulmonary organs. The dynamic deposition process and the nonuniform deposition pattern of PM _2.5 in the alveolar region are revealed using a fluorescent imaging method with high temporal and spatial resolutions. This observation technology would also bring insight in the study of the public health in air pollution and lung administration.

Chronic wounds are a major complication for diabetes mellitus (DM) patients, which cause discomfort and an increase in medical costs. The purpose of this study is to investigate the medical application and possible mechanisms of a cold atmospheric plasma jet in healing DM chronic wounds. In this paper, the genetic diabetic BKS.DB mice are used as the diabetic wound healing animal model, which have a stable glucose level and can avoid the effects or complications induced by surgical and chemical interventions. The helium atmospheric-pressure dielectric-barrier-discharge (AP-DBD) plasma jet is employed to treat the diabetic mice wounds with the fixed treatment time and distance of 15 s and 20.0 mm, respectively. The wound healing, histological, immunohistochemical, and cytokine analyses are conducted to evaluate the efficacy of the helium AP-DBD plasma jet on the chronic wound healing of the genetic diabetic mice. The experimental results show that the helium AP-DBD plasma jet treatment of wounds of genetic diabetic mice can regulate the secretion of transforming growth factor- $\beta $ (TGF- $\beta$ ) and fibroblast growth factors (FGFs), limit the inflammatory response and excessive cell proliferation, accelerate the process of re-epithelialization, and consequently, promote the chronic wound healing process.

Three-dimensional (3D) bioprinting is a novel technology utilizing biocompatible materials, cells, drugs, etc. as basic microcomponents to form 3D artificial structures and is believed as a promising method for regenerative medicine. Droplet-based bioprinting can precisely generate microspheres and manipulate them into organized structures with high fidelity. Biocompatible hydrogels are usually used as bioinks in 3D bioprinting, however, the viscosity of the bioink could be increased due to the additives such as cells, drugs, nutrient factors and other functional polymers in some particular applications, making it difficult to form monodispersed microspheres from high-viscosity bioink at the orifice of the nozzle. In this work, we reported a novel microfluidic-based printing nozzle to prepare monodispersed microspheres from high-viscosity bioink using the phase-inversion method. Different flowing conditions can be achieved by changing the flow rates of the fluids to form monodispersed solid and hollow microspheres using the same nozzle. The diameter of the microspheres can be tuned by changing the flow rate ratio and the size distribution of the microspheres is narrow. The prepared calcium alginate microspheres could also act as micro-carriers in drug delivery.

Surgical incision infection of multidrug-resistant microorganisms (e.g., methicillin-resistant Staphylococcus aureus , MRSA) is a severe cause of poor wound healing, which is prevalent in healthcare facilities and constitutes a huge infectious disease burden in the world. The purpose of this study is to investigate the medical application and possible mechanisms of the cold atmospheric plasma jet on infected wounds. In this article, the New Zealand rabbit in vivo wound infected with MRSA is used as the wound healing animal model. The helium atmospheric-pressure dielectric-barrier-discharge (AP-DBD) plasma jet is employed to treat the wounds infected with MRSA. The wound healing, histological, and cytokine analyses are conducted to evaluate the efficacy of the helium AP-DBD plasma jet on the MRSA-infected wound healing process. The experimental results show that the helium AP-DBD plasma jet treatment on the wounds infected with MRSA can regulate the secretion of the cytokines, limit the inflammatory response and cell excessive proliferation, accelerate the process of re-epithelialization, and consequently, promote the wound healing process and the inactivation of the bacteria.