Polyvinylpyrrolidone-passivated fluorescent iron oxide quantum dots for turn-off detection of tetracycline in biological fluids.

Tetracycline is an antibiotic that has been prescribed for COVID-19 treatment, raising concerns about antibiotic resistance after long-term use. This study reported fluorescent polyvinylpyrrolidone-passivated iron oxide quantum dots (IO QDs) for detecting tetracycline in biological fluids for the first time. The as-prepared IO QDs have an average size of 2.84 nm and exist a good stability under different conditions. The IO QDs' tetracycline detection performance could be attributed to a combination of static quenching and inner filter effect. The IO QDs displayed high sensitivity and selectivity toward tetracycline and achieved a good linear relationship with the corresponding detection limit being 91.6 nM.

Facile Synthesis of Bio-Antimicrobials with "Smart" Triiodides.

Multi-drug resistant pathogens are a rising danger for the future of mankind. Iodine (I2) is a centuries-old microbicide, but leads to skin discoloration, irritation, and uncontrolled iodine release. Plants rich in phytochemicals have a long history in basic health care. Aloe Vera Barbadensis Miller (AV) and Salvia officinalis L. (Sage) are effectively utilized against different ailments. Previously, we investigated the antimicrobial activities of smart triiodides and iodinated AV hybrids. In this work, we combined iodine with Sage extracts and pure AV gel with polyvinylpyrrolidone (PVP) as an encapsulating and stabilizing agent. Fourier transform infrared spectroscopy (FT-IR), Ultraviolet-visible spectroscopy (UV-Vis), Surface-Enhanced Raman Spectroscopy (SERS), microstructural analysis by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and X-Ray-Diffraction (XRD) analysis verified the composition of AV-PVP-Sage-I2. Antimicrobial properties were investigated by disc diffusion method against 10 reference microbial strains in comparison to gentamicin and nystatin. We impregnated surgical sutures with our biohybrid and tested their inhibitory effects. AV-PVP-Sage-I2 showed excellent to intermediate antimicrobial activity in discs and sutures. The iodine within the polymeric biomaterial AV-PVP-Sage-I2 and the synergistic action of the two plant extracts enhanced the microbial inhibition. Our compound has potential for use as an antifungal agent, disinfectant and coating material on sutures to prevent surgical site infections.

A Patient With Bilateral Conjunctivitis Positive for SARS-CoV-2 RNA in a Conjunctival Sample.

PURPOSE: To present a patient with bilateral conjunctivitis, testing positive for viral RNA of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in both nasopharyngeal and conjunctival samples. METHODS: A 40-year-old man with bilateral acute conjunctivitis and suspicious signs of coronavirus disease 2019 (COVID-19) presented to the hospital. A detailed ophthalmic examination was performed. Samples obtained from conjunctival and nasopharyngeal swabs were tested by reverse transcription PCR (RT-PCR) for the detection of SARS-CoV-2 virus. Ocular findings and duration of the presence of viral RNA in the conjunctival specimens were evaluated at follow-up visits. RESULTS: Slit-lamp biomicroscopy revealed bilateral acute follicular conjunctivitis. The RT-PCR assay demonstrated the presence of viral RNA in the nasopharyngeal and conjunctival specimens at the initial visit and at the 4-day follow-up. Conjunctivitis findings were decreased after 4 days and recovered completely without any sequelae within10 days. The PCR results of both nasopharyngeal and conjunctiva specimens were negative for the viral RNA at 10 days. CONCLUSIONS: Bilateral conjunctivitis is rare in patients infected with COVID-19. Although it is difficult to detect viral RNA from conjunctival swabs, conjunctival secretions may be a source of contamination, and protective measures must be taken.