[eng] The outbreak of the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS- CoV-2) pandemic has had a direct impact on the global health system, causing an alarming shortage of Personal Protective Equipment (PPE). Recent studies have shown that a significant number of healthcare professionals have been contaminated by the COVID-19 at their workplace due to the lack of appropriate PPE. Consequently, the PEE requirements have changed, making the use of filtering face-piece respirators (FFR) N95 and NK95 (FFP2 or FFP3, respectively) mandatory in place of the surgical masks previously used by healthcare professionals. Applying individualized face-seal devices in surgical masks, such as a thermoplastic resin ring, may significantly avoid inhalation of unfiltered air. Besides reducing leakage around the mask, which could convert surgical masks into PPE dual masks due to the high percentage of face-seal, it would allow bidirectional protection for both healthcare professionals and patients, thus becoming a medical device. The polylactic acid (corn starch) thermoplastic resin ring is the device proposed here to be used in order to decrease leakage of potentially contaminated air. The use of polylactic acid is of particular interest due to the fact that is a material appropriate for sanitary use, reusable and biodegradable. Therefore, healthcare professionals and organizations can maintain clinical activity in a cost-efficient manner whilst improving clinical safet
