Genetic Characteristics and Phenotype of Korean Patients with Stickler Syndrome: A Korean Multicenter Analysis Report No. 1.

Stickler syndrome is an inherited connective tissue disorder of collagen. There are relatively few reports of East Asian patients, and no large-scale studies have been conducted in Korean patients yet. In this study, we retrospectively analyzed the genetic characteristics and clinical features of Korean Stickler syndrome patients. Among 37 genetically confirmed Stickler syndrome patients, 21 types of gene variants were identified, of which 12 were novel variants. A total of 30 people had variants in the COL2A1 gene and 7 had variants in the COL11A1 gene. Among the types of pathogenic variants, missense variants were found in 11, nonsense variants in 8, and splice site variants in 7. Splicing variants were frequently associated with retinal detachment (71%) followed by missense variants. This is the first large-scale study of Koreans with Stickler syndrome, which will expand the spectrum of genetic variations of Stickler syndrome.

Direct monitoring of protease activity using an integrated microchip coated with multilayered fluorogenic nanofilms.

Proteases play an essential role in the four sequential but overlapping phases of wound healing: hemostasis, inflammation, proliferation, and remodeling. In chronic wounds, excessive protease secretion damages the newly formed extracellular matrix, thereby delaying or preventing the normal healing process. Peptide-based fluorogenic sensors provide a visual platform to sense and analyze protease activity through changes in the fluorescence intensity. Here, we have developed an integrated microfluidic chip coated with multilayered fluorogenic nanofilms that can directly monitor protease activity. Fluorogenic protease sensors were chemically conjugated to polymer films coated on the surface of parallel microfluidic channels. Capillary flow layer-by-layer (CF-LbL) was used for film assembly and combined with subsequent sensor modification to establish a novel platform sensing technology. The benefits of our platform include facile fabrication and processing, controllable film nanostructure, small sample volume, and high sensitivity. We observed increased fluorescence of the LbL nanofilms when they were exposed to model recombinant proteases, confirming their responsiveness to protease activity. Increases in the nanofilms' fluorescence intensity were also observed during incubation with liquid extracted from murine infected wounds, demonstrating the potential of these films to provide real-time, in situ information about protease activity levels.

Microfluidic preparation, shrinkage, and surface modification of monodispersed alginate microbeads for 3D cell culture.

Functionalized alginate microbeads (MB) have been widely used for three-dimensional (3D) culture of cells and creating biomimetic tissue models. However, conventional methods for preparing these MB suffer from poor polydispersity, due to coalescence of droplets during the gelation process and post-aggregation. It remains an immense challenge to prepare alginate MB with narrow size distribution and uniform shape, especially when their diameters are similar to the size of cells. In this work, we developed a simple method to produce monodispersed, cell-size alginate MB through microfluidic emulsification, followed by a controlled shrinkage process and gelation in mineral oil with low concentration of calcium ion (Ca2+). During the gelation process caused by the diffusion of Ca2+ from the oil to water phase, a large amount of satellite droplets with sub-micrometer sizes was formed at the water/oil interface. As a result, each original droplet was transformed to one shrunken-MB with much smaller size and numerous submicron-size satellites. To explore the feasibility of the shrunken-MB for culturing with cells, we have successfully modified a variety of polymer nanofilms on MB surfaces using a layer-by-layer assembly approach. Finally, the nanofilm-modified MB was applied to a 3D culture of GFP-expressing fibroblast cells and demonstrated good biocompatibility.

Cell Isolation and Recovery Using Hollow Glass Microspheres Coated with Nanolayered Films for Applications in Resource-Limited Settings.

Established cell isolation and purification techniques such as fluorescence-activated cell sorting (FACS), isolation through magnetic micro/nanoparticles, and recovery via microfluidic devices have limited application as disposable technologies appropriate for point-of-care use in remote areas where lab equipment as well as electrical, magnetic, and optical sources are restricted. We report a simple yet effective method for cell isolation and recovery that requires neither specialized lab equipment nor any form of power source. Specifically, self-floating hollow glass microspheres were coated with an enzymatically degradable nanolayered film and conjugated with antibodies to allow both fast capture and release of subpopulations of cells from a cell mixture. Targeted cells were captured by the microspheres and allowed to float to the top of the hosting liquid, thereby isolating targeted cells. To minimize nonspecific adhesion of untargeted cells and to enhance the purity of the isolated cell population, an antifouling polymer brush layer was grafted onto the nanolayered film. Using the EpCAM-expressing cancer cell line PC-3 in blood as a model system, we have demonstrated the isolation and recovery of cancer cells without compromising cell viability or proliferative potential. The whole process takes less than 1 h. To support the rational extension of this platform technology, we introduce extensive characterization of the critical design parameters: film formation and degradation, grafting with a poly(ethylene glycol) (PEG) sheath, and introducing functional antibodies. Our approach is expected to overcome practical hurdles and provide viable targeted cells for downstream analyses in resource-limited settings.

Comparison of OCT measurements between high myopic and low myopic children.

PURPOSE: To compare the peripapillary retinal nerve fiber layer (RNFL) thickness, macular thickness, and total macular volume of high myopic eyes with those of low myopic eyes in children younger than 10 years. METHODS: Prospective, randomized, comparative study. Time-domain optical coherence tomography (OCT) (Stratus OCT; Carl Zeiss Meditec) was performed on 15 children with high myopia (refractive error greater than or equal to -6.0 diopters [D], group 1) and 20 children with low myopia (0 less than refractive error from -0.25 to -3.0 D, group 2). Fast RNFL scan and a fast macular scan with OCT were performed in both groups. The authors compared the data between the two groups. RESULTS: The mean age of the patients with high myopia was 7.8 years and that of those with low myopia was 7.2 years. The mean overall thickness of the peripapillary RNFL was 100.8 µm in the high myopes and 110.5 µm in the low myopes. There was a statistically significant difference in the overall RNFL thickness between the two groups (p < 0.05). In addition, peripapillary RNFL thinning was especially prominent in the inferior quadrant in children with high myopia (p = 0.021). The mean values of macula thickness and volume for high myopes were also significantly smaller than the mean values for low myopes (p < 0.05). CONCLUSIONS: The inferior quadrant and the overall peripapillary RNFL were significantly thinner in high myopic children relative to low myopic children. High myopic children had significantly thinner macular thickness and lower macular volumes. These structural differences should be considered in the clinical assessment of high myopic children.