Summary
Aims: To develop novel polypropylene composite materials with antimicrobial activity by adding different types of copper nanoparticles.
Methods and Results: Copper metal (CuP) and copper oxide nanoparticles (CuOP) were embedded in a polypropylene (PP) matrix. These composites present strong antimicrobial behaviour against E. coli that depends on the contact time between the sample and the bacteria. After just 4 h of contact, these samples are able to kill more than 95% of the bacteria. CuOP fillers are much more effective eliminating bacteria than CuP fillers, showing that the antimicrobial property further depends on the type of copper particle. Cu2+ released from the bulk of the composite is responsible for this behaviour. Moreover, PP/CuOP composites present a higher release rate than PP/CuP composites in a short time, explaining the antimicrobial tendency.
Conclusions: Polypropylene composites based on copper nanoparticles can kill E. coli bacteria depending on the release rate of Cu2+ from the bulk of the material. CuOP are more effective as antimicrobial filler than CuP.
Significance and Impact of the Study: Our findings open up novel applications of these ion‐copper‐delivery plastic materials based on PP with embedded copper nanoparticles with great potential as antimicrobial agents.
Background
The use of kinetic impact projectiles (KIPs) for crowd-control has increased worldwide. Despite having been created as non-lethal weapons, significant damage to several organs, including the eye, has been reported. In this study, we investigated cases of ocular trauma from KIPs during the civil unrest in Chile. To our knowledge, this is the largest case series recorded in international literature.
Methods
We included all patients who sought care or were referred to the Eye Trauma Unit, a national referral centre in Santiago, Chile, during the civil unrest from October 18 to November 30, 2019. We reviewed paper medical records and extracted data on suspected cause of trauma, type of trauma, visual acuity and sociodemographic data.
Results
We included 259 patients, out of which in 182 cases (70.5%) KIPs were the suspected cause. Cases by KIPs were predominantly male (86.6%), young (median age 26.3, interquartile range 22.0–31.4) and living in the Metropolitan Region. Eighty-nine patients (48.9%) had severe visual impairment or were blind at the first examination. The trauma was an open-globe injury in 20.3% of cases and 13 cases required evisceration of the ocular content. Compared to other causes of ocular trauma, KIPs were related to a more severe loss of visual acuity and a higher frequency of open-globe injuries.
Conclusions
The use of KIPs during a period of civil unrest in Chile resulted in severe ocular trauma, visual impairment and permanent disability. KIPs should be avoided as a method of crowd-control.
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