This study shows that alkali-injured corneal epithelial wounds heal faster when treated with amniotic membrane suspension than with autologous serum or preservative-free artificial tears.

Nowadays, flexible triboelectric sensors are the most promising candidates for wearable energy harvesting and medical applications. In the present investigation, the self-powered flexible triboelectric sensors (SF-TESs) were fabricated by using roughness-created Ecoflex cast film and melt-blown nonwoven polyurethane layers. SF-TESs were prepared using sandpaper (60 grit size) as a substrate, showing better triboelectric performance due to high surface roughness and low density compared to others, and it is an optimum condition. The optimized SF-TES can scavenge a maximum open-circuit output voltage (V OC) and power density values for the sensor without and with a spacer were 139 V and 1.6 Wm–2 and 320 V and 6 Wm–2, respectively. The spacer sample showed 2.3 times higher V OC and 3.7 times higher power density values than without a spacer at a constant load of 4.4 N and a frequency of 5 Hz. The SF-TES can directly operate 15 light-emitting diodes (LEDs) and switch on an LCD timer, and it is powered for 5 s when connected through a rectifier and a capacitor. In contrast, the sensor with a spacer can operate more than 100 LEDs directly. Further, the triboelectric output performances V OC and short-circuit current (I SC) gradually increase from 65 to 139 V and 2.3 to 4.6 μA, respectively, when the external load increases from 2.2 to 8.8 N. Based on the above results, we can clearly say that the surface roughness, spacing between the frictional layers, and external load are critical parameters for enhancing the triboelectric performance. The as-prepared SF-TESs have potential medical applications in the intelligent beds for observing the physical activity of coma patients, patients suffering from cardiovascular diseases, and sleep apnea.

A flexible and portable triboelectric nanogenerator (TENG) based on electrospun polyvinylidene fluoride (PVDF) doped with copper oxide (CuO) nanoparticles (NPs, 2, 4, 6, 8, and 10 wt.-% w.r.t. PVDF content) was fabricated. The structural and crystalline properties of the as-prepared PVDF-CuO composite membranes were characterized using SEM, FTIR, and XRD. To fabricate the TENG device, the PVDF-CuO was considered a tribo-negative film and the polyurethane (PU) a counter-positive film. The output voltage of the TENG was analyzed using a custom-made dynamic pressure setup, under a constant load of 1.0 kgf and 1.0 Hz frequency. The neat PVDF/PU showed only 1.7 V, which further increased up to 7.5 V when increasing the CuO contents from 2 to 8 wt.-%. A decrease in output voltage to 3.9 V was observed for 10 wt.-% CuO. Based on the above results, further measurements were carried out using the optimal sample (8 wt.-% CuO). Its output voltage performance was evaluated as a function of varying load (1 to 3 kgf) and frequency (0.1 to 1.0 Hz) conditions. Finally, the optimized device was demonstrated in real-time wearable sensor applications, such as human motion and health-monitoring applications (respiration and heart rate).

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