Scientists create virucidal silicon surface without any chemicals
phys.org
phys.org
> ABSTRACT: This paper presents a comprehensive experimental and theoretical investigation into the antiviral properties of nanostructured surfaces and explains the underlying virucidal mechanism. We used reactive ion etching to fabricate silicon (Si) surfaces featuring an array of sharp nanospikes with an approximate tip diameter of 2 nm and a height of 290 nm. The nanospike surfaces exhibited a 1.5 log reduction in infectivity of human parainfluenza virus type 3 (hPIV-3) after 6 h, a substantially enhanced efficiency, compared to that of smooth Si. Theoretical modeling of the virus–nanospike interactions determined the virucidal action of the nanostructured substrata to be associated with the ability of the sharp nanofeatures to effectively penetrate the viral envelope, resulting in the loss of viral infectivity. Our research highlights the significance of the potential application of nanostructured surfaces in combating the spread of viruses and bacteria. Notably, our study provides valuable insights into the design and optimization of antiviral surfaces with a particular emphasis on the crucial role played by sharp nanofeatures in maximizing their effectiveness.
> Spike the viruses to kill them. This seemingly unsophisticated concept requires considerable technical expertise and has one great advantage: a high virucidal potential that does not require the use of chemicals. The process of making the virucidal surfaces starts with a smooth metal plate, which is bombarded with ions to strategically remove material.
> The result is a surface full of needles that are 2 nanometers thick—30,000 would fit in a hair—and 290 high.
> [...] The research has revealed how these processes work and that they are 96% effective
> Staph is spread by direct contact and by touching items that are contaminated such as towels, sheets, privacy curtains, and clothing. As noted by the San Francisco Chronicle, “It is estimated that each year 2 million Americans become infected during hospital stays, and at least 90,000 of them die. MRSA (an antibiotic resistant strain of staph) is a leading cause of hospital-borne infections.” One of the most important recent discoveries is hemp’s ability to kill surface bacteria, while cotton, polyester, and polyethylene allow it to remain on their surfaces for up to months at a time. [...]
> Hemp fabric was tested against two bacteria strains, Staphylococcus Aureus (staph) and Klebsiella Pneumoniae (pneumonia). The fabric tested was a hemp blend, 60% hemp and 40% rayon. The staph test sample was already 98.5% bacteria free during the first measurement of the testing, while the pneumonia fabric sample was 65.1% bacteria free. These results, even prior to the tests completion, clearly display the fabrics unique capability at killing bacteria and reducing their spread. This is especially imperative for healthcare facilities.
> For infrared testing, the same hemp blend was analyzed resulting in a test result of 0.893, or nearly 90% resistant. Different blended fabrics have the potential to increase the percentage of this initial test, especially fabrics with a higher percentage of hemp. Many of hemp’s applications will benefit our military, and EnviroTextile’s hemp fabrics have recently been approved by the USDA as Federally Preferred for Procurement under their BioPreferred Program.