Comparison of the structural integrity and quality of corneal endothelium stored in organ culture storage medium versus Eusol-C.

In this experimental study, we compared the structural integrity and cell quality of corneal endothelium stored in organ culture medium (OCS) and Eusol-C. The experiment included rabbit and human cornea experiments in vitro. Thirty rabbit corneas and thirty-two human corneas were collected and divided into two groups. All right corneas were allocated in experiment group and left corneas were placed in control group. The corneas in experimental group were stored in OCS at 34 °C, and the corneas in control group were stored in Eusol-C at 4 °C for 7, 14, 21, 28, and 35 days, respectively. Endothelial cell morphology, cell count, and trypan blue staining for viability were assessed before storage (Day 0) and at days 7, 14, 21, 28 and 35. The structural integrity of human corneal endothelial cell was analyzed using immunohistochemistry. The samples of storage solution for microbial culture were collected on the third day and at the end of storage. The results show that no bacterial and fungal infections were found in both groups. After 14 days of storage, the morphology of endothelial cell was better in the experimental group than in the control group. The endothelial cell stored in OCS were better than those stored in Eusol-C at the end of storage times, except human cornea 14 days storage group. The ZO-1 protein staining showed the typical polygonal morphology of endothelial cell stored in the OCS. Corneal endothelial cells stored in the OCS had better quality up to 28 days. It can be applied to Chinese eye banks as a method of corneal preservation.

Carbodiimide crosslinked decellularized lenticules as a drug carrier for sustained antibacterial eye treatments.

In this study, the drug-loading and antibacterial activity of carbodiimide/N-hydroxysuccinimide (EDC/NHS) crosslinked decellularized lenticules (CDLs) were evaluated. Small incision lenticule extraction derived lenticules were decellularized and modified with crosslinking concentrations of 0.00 (E/L00, non-crosslinked), 0.01 (E/L01), 0.05 (E/L05) and 0.25 mmol (E/L25) EDC per mg lenticules at 5:1 EDC/NHS ratios with non-decellularized non-crosslinked lenticules (NDLs) as controls. NDLs and EDC/NHS CDLs had similar water contents. The light transmittance percentages (400-800 nm) were 91.55 ± 1.16%, 88.68 ± 1.19%, 80.86 ± 1.94%, 85.12 ± 2.42% and 85.62 ± 2.84% for NDLs, E/L00, E/L01, E/L05 and E/L25, respectively (P< 0.01). The EDC/NHS CDLs (diameter: 6.36 ± 0.18 mm; central thickness: 117.31 ± 3.46 µm) were soaked in 3% (wt./vol.) levofloxacin (LEV) solution for 3 h. The drug release concentrations of LEV-impregnated EDC/NHS CDLs were determined by high-performance liquid chromatography. Zone inhibition (ZOI) againstStaphylococcus aureusof E/L01, E/L05 and E/L25 were superior to E/L00 CDLs (P< 0.01) and among the different crosslinked groups, E/L05 lenticules produced the largest ZOIs and their drug concentration release over 21 d was the highest. EDC/NHS crosslinking can improve the drug-loading effect and antibacterial activity of decellularized lenticules. LEV-impregnated EDC/NHS CDLs are promising drug delivery carriers.

Synergistic Effect between Ultra-Small Nickel Hydroxide Nanoparticles and Reduced Graphene Oxide sheets for the Application in High-Performance Asymmetric Supercapacitor.

Nanoscale electrode materials including metal oxide nanoparticles and two-dimensional graphene have been employed for designing supercapacitors. However, inevitable agglomeration of nanoparticles and layers stacking of graphene largely hamper their practical applications. Here we demonstrate an efficient co-ordination and synergistic effect between ultra-small Ni(OH)2 nanoparticles and reduced graphene oxide (RGO) sheets for synthesizing ideal electrode materials. On one hand, to make the ultra-small Ni(OH)2 nanoparticles work at full capacity as an ideal pseudocapacitive material, RGO sheets are employed as an suitable substrate to anchor these nanoparticles against agglomeration. As a consequence, an ultrahigh specific capacitance of 1717 F g(-1) at 0.5 A g(-1) is achieved. On the other hand, to further facilitate ion transfer within RGO sheets as an ideal electrical double layer capacitor material, the ultra-small Ni(OH)2 nanoparticles are introduced among RGO sheets as the recyclable sacrificial spacer to prevent the stacking. The resulting RGO sheets exhibit superior rate capability with a high capacitance of 182 F g(-1) at 100 A g(-1). On this basis, an asymmetric supercapacitor is assembled using the two materials, delivering a superior energy density of 75 Wh kg(-1) and an ultrahigh power density of 40 000 W kg(-1).

Insight into the formation mechanism of graphene quantum dots and the size effect on their electrochemical behaviors.

To study the formation mechanism and influencing factors of graphene quantum dots (GQDs), GQDs with different average sizes were prepared using a modified hydrothermal method with hydrogen peroxide (H2O2) as an etching agent and ammonia as an assistant. It is found that size-controlled GQDs were prepared by adjusting the amount of ammonia and porous reduced graphene oxide (PRGO) debris can be synthesized by reducing the hydrothermal reaction time. Structural changes of final products were mainly attributed to the changes in the etching ability of the hydroxyl radical (OH˙) against the reduction ability of the hydroxyl group (OH(-)) in different alkaline environments regulated by ammonia. Furthermore, we studied the electrochemical properties of GQDs and PRGO. The results showed that the specific capacitance of all samples increases linearly with the size and the smallest GQDs can work at the highest scan rate of as high as 5000 V s(-1) with an ultra-fast power response (τ0 = 63.3 µs). Thus, these findings elucidate the formation mechanism of GQDs and demonstrate that GQDs are applicable in microelectronic devices with high power response requirements.