Electronic retinal prostheses for stimulating retinal neurons are promising for vision restoration. However, the rigid electrodes of conventional retinal implants can inflict damage on the soft retina tissue. They also have limited selectivity due to their poor proximity to target cells in the degenerative retina. Here we present a soft artificial retina (thickness, 10 μm) where flexible ultrathin photosensitive transistors are integrated with three-dimensional stimulation electrodes of eutectic gallium–indium alloy. Platinum nanoclusters locally coated only on the tip of these three-dimensional liquid-metal electrodes show advantages in reducing the impedance of the stimulation electrodes. These microelectrodes can enhance the proximity to the target retinal ganglion cells and provide effective charge injections (72.84 mC cm⁻²) to elicit neural responses in the retina. Their low Young’s modulus (234 kPa), owing to their liquid form, can minimize damage to the retina. Furthermore, we used an unsupervised machine learning approach to effectively identify the evoked spikes to grade neural activities within the retinal ganglion cells. Results from in vivo experiments on a retinal degeneration mouse model reveal that the spatiotemporal distribution of neural responses on their retina can be mapped under selective localized illumination areas of light, suggesting the restoration of their vision.

Ubiquitination of core stem cell transcription factors can directly affect stem cell maintenance and differentiation. Ubiquitination and deubiquitination must occur in a timely and well‐coordinated manner to regulate the protein turnover of several stemness related proteins, resulting in optimal embryonic stem cell maintenance and differentiation. There are two switches: an E3 ubiquitin ligase enzyme that tags ubiquitin molecules to the target proteins for proteolysis and a second enzyme, the deubiquitinating enzyme (DUBs), that performs the opposite action, thereby preventing proteolysis. In order to maintain stemness and to allow for efficient differentiation, both ubiquitination and deubiquitination molecular switches must operate properly in a balanced manner. In this review, we have summarized the importance of the ubiquitination of core stem cell transcription factors, such as Oct3/4, c‐Myc, Sox2, Klf4, Nanog, and LIN28, during cellular reprogramming. Furthermore, we emphasize the role of DUBs in regulating core stem cell transcriptional factors and their function in stem cell maintenance and differentiation. We also discuss the possibility of using DUBs, along with core transcription factors, to efficiently generate induced pluripotent stem cells. Our review provides a relatively new understanding regarding the importance of ubiquitination/deubiquitination of stem cell transcription factors for efficient cellular reprogramming.

Purpose.: To determine the effects of age, sex, spherical equivalent, axial length, anterior chamber depth, optic disc area, and central corneal thickness on perimacular inner retinal layer thickness in the normal human eye as measured by Fourier-domain optical coherence tomography (FD-OCT). Methods.: In this cross-sectional observational study, 182 Korean healthy subjects aged from 22 to 84 years were included. To obtain the inner retinal layer thickness, perimacular ganglion cell complex thickness, which extends from the internal limiting membrane to the inner nuclear layer, was measured by FD-OCT on one randomly selected eye of each subject. Linear regression analyses of the effects of demographic and clinical variables, including age, sex, spherical equivalent, axial length, anterior chamber depth, optic disc area, and central corneal thickness, on perimacular inner retinal layer thickness were performed. Results.: The mean inner retinal layer thickness for the entire population was 93.87 μm. Thinner inner retinal layer measurements were associated with older age (P = 0.010) and greater axial length (P = 0.021). Mean inner retinal layer thickness decreased by approximately 1.59 μm for every decade of age and by approximately 1.56 μm for every 1-mm greater axial length. There was no relationship between inner retinal layer thickness and sex, anterior chamber depth, optic disc area, or central corneal thickness. Conclusions.: Inner retinal layer thickness, as measured by FD-OCT, varies significantly with age and axial length. The effect is small but clinically relevant in the interpretation of inner retinal layer thickness measurements.