Synthesis of Highly Near-Infrared Fluorescent Graphene Quantum Dots Using Biomass-Derived Materials for In Vitro Cell Imaging and Metal Ion Detection.

Graphene quantum dots (GQDs) are a subset of fluorescent nanomaterials that have gained recent interest due to their photoluminescence properties and low toxicity and biocompatibility features for bioanalysis and bioimaging. However, it is still a challenge to prepare highly near-infrared (NIR) fluorescent GQDs using a facile pathway. In this study, NIR GQDs were synthesized from the biomass-derived organic molecule cis-cyclobutane-1,2-dicarboxylic acid via one-step pyrolysis. The resulting GQDs were then characterized by various analytical methods such as UV-Vis absorption spectroscopy, fluorescence spectroscopy, dynamic light scattering, high-resolution transmission electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. Moreover, the photostability and stability over a wide pH range were also investigated, which indicated the excellent stability of the prepared GQDs. Most importantly, two peaks were found in the fluorescence emission spectra of the GQDs, one of which was located in the NIR region of about 860 nm. Finally, the GQDs were applied for cell imaging with human breast cancer cell line, MCF-7, and cytotoxicity analysis with mouse macrophage cell line, RAW 246.7. The results showed that the GQDs entered the cells through endocytosis on the fluorescence images and were not toxic to the cells up to a concentration of 200 µg/mL. Thus, the developed GQDs could be a potential effective fluorescent bioimaging agent. Finally, the GQDs depicted fluorescence quenching when treated with mercury metal ions, indicating that the GQDs could be used for mercury detection in biological samples as well.

A randomized comparison of the GlideScope videolaryngoscope to the standard laryngoscopy for intubation by pediatric residents in simulated easy and difficult infant airway scenarios.

BACKGROUND: Videolaryngoscopy has been developed mainly to assist difficult airway intubation. However, there is a lack of studies demonstrating the real efficacy of its use in children. In this study, we tested the hypothesis that GlideScope (Verathon Inc, Bothell, Wash) videolaryngoscope improves tracheal intubation when used by pediatric residents in an advanced patient simulation model. METHODS: Pediatric residents who passed a pediatric advanced life support course were eligible for the study. An advanced infant simulator was used, and 4 scenarios were proposed: normal airway (NA), tongue edema (TE), tongue edema and oropharyngeal edema, and cervical collar. No participant had prior experience with any videolaryngoscope. After a brief instruction in GlideScope technique, each participant performed the 4 scenarios using both the standard Miller and GlideScope laryngoscopes, in a random sequence. RESULTS: Sixteen residents were included. The number of failed intubations was higher with GlideScope in NA and TE scenarios (3 vs 0, in both cases). Mean (SD) time to successful intubation was significantly longer with GlideScope in the NA scenario (GlideScope, 38 [SD, 13] vs Miller, 26 [SD, 16] seconds; P = 0.043). The number of maneuvers was significantly higher with GlideScope in the tongue edema and oropharyngeal edema scenario (2.3 [SD, 1.5] vs 1.5 [SD, 1]; P = 0.04). Upper jaw injury index was significantly lower with GlideScope in NA (2.0 [SD, 1] vs 2.6 [SD, 0.8]; P = 0.008) and cervical collar (2.1 [SD, 1.0] vs 2.8 [SD, 0.5]; P = 0.011) scenarios. Participants considered GlideScope technique more difficult than standard Miller in NA (5 [SD, 2.0] vs 3 [SD, 1.3]; P = 0.04) and TE (5.9 [SD, 2.5] vs 3.9 [SD, 1.7]; P = 0.02) scenarios. CONCLUSIONS: In simulated scenarios of infant NA and difficult airway, when used by pediatric residents, GlideScope did not improve intubation performance when compared with the standard laryngoscope. Nevertheless, GlideScope may be safer for upper jaw injury and could have advantages in the management of complicated airway. Further studies are needed to assess if specific training will improve GlideScope intubation performance and whether the "in simulator" results translate into clinical practice.