Antimicrobial coatings to reduce infection transmission risk on fingerprint scanners
04 February 2021 16:27 GMT

By Roberto Wolfer, CEO, JENETRIC

Given the pandemic situation, hygiene and fingerprints have become discussed much more than in previous years. Similar to any other surface that people touch with their hands, fingerprint scanners are a potential source for the transmission of bacteria and viruses from one person to another. Since touchless fingerprint technologies are not certified for identification with either flat or rolled fingerprints, touch-based fingerprint scanners are the only choice when it comes to applications that require forensic quality fingerprints.

Disinfecting and sterilizing fingerprint scanners

Depending on the material, bacteria and viruses can survive on surfaces between a few hours and several days. Regular disinfection of the contact surfaces helps to reduce the risk of infection effectively *1. However, it requires a careful regimen of disinfection and a continuous availability of cleaning supplies. There are other means to disinfect and sterilize surfaces, such as with UV radiation or ozone treatment, but these measures require additional equipment, trained personnel, and cause downtime when the fingerprint scanner cannot be used.

On the other hand, antimicrobial coatings have been available for many years and have been proven to inactivate microorganisms effectively. Furthermore, they do not require any additional equipment or consumables to be used.

When applying an antimicrobial coating to fingerprint scanners, various parameters need to be considered:

- Effective against bacteria and viruses

- Nontoxic and non-sensitizing to human skin

- No loss in fingerprint quality

- Durable and robust against abrasion and cleaning

- Harmless to the materials of the fingerprint scanner

Antimicrobial coating

Copper has been used extensively as an agent in antimicrobial coatings. Used as water lines, on roofs and as an antifouling component in paints, copper’s antimicrobial properties have been well known for decades. In hospitals, copper alloys are already used to reduce the risk of infections on handrails, doorknobs and bed rails.

When microorganisms come into contact with copper there are several mechanisms that kill them: disruption of the cell wall, oxidative stress to cells, and interaction with the proteins that keep the microorganism alive. As a result, the bacterial or viral genome is fragmented thus ensuring that the inactivation is irreversible.

Copper has been proven to kill microorganisms such as MRSA, E. coli, Influenza A and Norovirus [*2]. In a study published by Warnes et al. it has been shown that copper alloys also kill enveloped viruses, such as the human coronavirus 229E (HuCov-229E), one of the seven corona viruses, successfully [*3]. The first damage to HuCoV-229E was observed within minutes after coming into contact with the copper. In a very recent study van Doremalen et al. showed that SARS-CoV-2 virus survives on surfaces from 4 hours (copper) to several days (plastic) [*4].

Reduced infection risk with JENETRIC’S fingerprint scanners

The antimicrobial coating used by JENETRIC is applied by using Combustion Chemical Vapor Deposition (CCVD) at atmospheric pressure. This process enables a gas phase reaction of inorganic particles. Copper-II-oxide (or cupric oxide) is used as the antimicrobial agent, which is officially listed as biocidal agent in the European Biocidal Directive 98/8/EC.

Careful investigation of the fingerprint quality for FBI Appendix F image quality parameters, NFIQ 2.0 quality checks, and visual assessment did not show any impact on the fingerprint quality due to the antimicrobial coating.

In order to simulate the real-life use of the coated fingerprint scanner, both washability and severe abrasion were tested. Washability (the resistance against cleaning agents) was tested by using brushes and a wet environment according to ASTM D4213-92/D4828 [*5], and severe abrasion was tested in accordance with ISO 1518-1 with a scratch resistance testing device

RH3 (Coesfeld GmbH & Co. KG) using steel wool as a load body and an additional load of 1000 g. After these tests, a sufficient film thickness of the antimicrobial coating was verified, and biological tests proved the lack of microbial activity.

In summary, our antimicrobial coating is a proven measure that not only kills bacteria and viruses but also does not impact the fingerprint quality, harms human skin, or damages the fingerprint scanner in any way.

Notes:

[1]https://www.jenetric.com/fileadmin/user_upload/Downloads/Disinfection_LIVETOUCH_scanners_JENETRIC_Stand_05_20.pdf

[2] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4561453/

[3] https://mbio.asm.org/content/6/6/e01697-15

[4] https://www.nejm.org/doi/pdf/10.1056/NEJMc2004973?articleTools=true

[5] American Society for Testing and Materials

 

 

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connect:ID 2021 5-6 Oct 21