Packing of metalized polymer nanofibers for aneurysm embolization

The Role of Nanomaterials in Stroke Treatment: Targeting Oxidative Stress

Stroke has a high rate of morbidity and disability, which seriously endangers human health. In stroke, oxidative stress leads to further damage to the brain tissue. Therefore, treatment for oxidative stress is urgently needed. However, antioxidative drugs have demonstrated obvious protective effects in preclinical studies, but the clinical studies have not seen breakthroughs. Nanomaterials, with their characteristically small size, can be used to deliver drugs and have demonstrated excellent performance in treating various diseases. Additionally, some nanomaterials have shown potential in scavenging reactive oxygen species (ROS) in stroke according to the nature of nanomaterials. The drugs' delivery ability of nanomaterials has great significance for the clinical translation and application of antioxidants. It increases drug blood concentration and half-life and targets the ischemic brain to protect cells from oxidative stress-induced death. This review summarizes the characteristics and progress of nanomaterials in the application of antioxidant therapy in stroke, including ischemic stroke, hemorrhagic stroke, and neural regeneration. We also discuss the prospect of nanomaterials for the treatment of oxidative stress in stroke and the challenges in their application, such as the toxicity and the off-target effects of nanomaterials.

Transparent Metallized Microfibers as Recyclable Electrostatic Air Filters with Ionization

Air-quality control remains a major environmental concern as polluted air is a threat to public safety and health in major industrialized cities. To filter pollutants, fibrous filters employing electrostatic attraction have been widely used. However, such air filters suffer from some major disadvantages, including low recyclability and a significant pressure drop owing to clogging and a high packing density. Herein, we developed ionization-assisted electrostatic air filters consisting of nonwoven nanofibers. Ionization of particulate matter (PM) using air ionization enhanced the electrostatic attraction, thereby promoting efficient filtration. Metallization of the fibers facilitated strong electrical attraction and the consequent capture of PM of various sizes. The low packing density of the metallized fibers also facilitated efficient filtration of the PM, even at low driving pressures, which in turn reduced the energy consumption of the air-filtration device.

In vitro evaluation of Pt-coated electrospun nanofibers for endovascular coil embolization

Recently, endovascular coil embolization has been introduced to treat intracranial aneurysms because it has lower morbidity and mortality than surgical clipping. The endovascular coils prevent the extravasation of blood by decreasing the permeability of an aneurysm flow governed by Darcy's law. Here, we developed and explored Pt-coated micro-ropes for potential use as endovascular coils. Electrospinning with subsequent electroplating were employed to fabricate Pt-coated nanofibers, which were tightly twisted to form micro-ropes. The compatibility of Pt micro-ropes with commercial delivery catheters was verified and their performance was experimentally explored in an in vitro experimental model. The developed Pt-coated micro-ropes demonstrated feasibility as efficient and low-cost endovascular coils. STATEMENT OF SIGNIFICANCE: The use of Platinum (Pt)-coated polymer nanofibers to prevent blood extravasation has been demonstrated. These Pt nanofibers were installed within a microfluidic channel, and the resulting reduced permeability was evaluated using a fluid similar to blood. Based on the obtained results, these newly developed nanofibers are expected to decrease the operation cost for aneurysmal subarachnoid hemorrhage (SAH), owing their reduced size and low material cost. Overall, the use of this new material should reduce the operational risk associated with the multiple steps required to place the Pt coils at the SAH site. The compatibility of Pt micro-ropes with commercial delivery catheters was verified and their performance was experimentally explored in an in vitro experimental model. The developed Pt-coated micro-ropes demonstrated feasibility as efficient and low-cost endovascular coils.

Electrostatic Transparent Air Filter Membranes Composed of Metallized Microfibers for Particulate Removal

Particulate matter (PM) from ever-increasing industrialization poses a great public health risk. Although fiber-based filters are used effectively to block PM, filters with high packing densities suffer from excessive pressure drops. Electret filters bypass intermediate- or large-sized particles and thus capture only small particles, the motion of which can be influenced by weak electrostatic fields. In this study, we demonstrate the fabrication of metallized fibers that produce intense electric fields, thereby enabling capture of PMs of a variety of sizes produced by burning incense. The filter consisting of these metallized fibers effectively removes moving particles from air. An electricity-driven filter is relatively thin and has a low packing density, making it light, portable, transparent, and inexpensive. The sizes of the pores between the metallized fibers are readily controlled by manipulating the electrospinning and electroplating times. Sufficiently large pores permit efficient airflow and thus increase permeability without risking an excessive pressure drop. The metallized fiber filter is washable and thus reusable. In this study, a PM removal rate of >97% was recorded using a filter designed under optimal conditions.