Polyurethane/gelatin nanofiber neural guidance conduit in combination with resveratrol and Schwann cells for sciatic nerve regeneration in the rat model

Peripheral nerve injury is a serious challenge which influences 2.8 percent of trauma patients. Tissue engineering of peripheral nerves mainly focuses on axonal regeneration via various nerve guides. The aim of this study is to evaluate a novel polyurethane (PU)/gelatin nanofibers (GNFs) conduit’s potential combination with resveratrol (RVT) for sciatic nerve regeneration in the rat. Platelet-rich plasma (PRP) was used as a carrier for RVT. Different tests like contact angle, tensile strength etc. was used to evaluate properties of PU/GNFs conduits. In addition, the electron microscopy, MTT assay, and DAPI staining revealed its compatibility with Schwann cells. 24 male Wistar rats were allocated into four groups (n=6) (1) PU/GNF/PRP/Schwann cell, 2) PU/GNF/Schwann cell/PRP/RVT, 3) Positive control, and 4) Negative control in order to assess sciatic functional index (SFI), hot plate latency, electromyographical (EMG), the percentage of wet weight-loss of gastrocnemius muscle and histopathological studies using hematoxylin-eosin staining. The results represented sciatic functional index (SFI), hot plate latency, electromyographical improved significantly in group 1 and 2 compared to the negative control group. Histopathological findings showed remarkable improvements in myelin sheath regeneration and fibers condition in group 1 and 2 compared to the negative control group. Group 2 showed more resemblance to the normal sciatic nerve, with well-arranged fibers and an intact myelin sheath. This study successfully applied PU/GNFs/PRP/RVT conduits as a potential biocompatible nerve guide with proper mechanical properties, biocompatibility, and biodegradability that enhanced injured sciatic nerve’s recovery rate

Laser induced periodic surface structured c-Si solar cell with more than 16% efficiency

Crystalline-Si (c-Si) based solar cells (SC) efficiency remains one of the most challenging part in photovoltaic industry. Besides of the thermodynamical limits, the optical losses due to indirect band-gap structure of the material require additional treatment which known as a photonic design of the SC surface [1]. Numerous manipulations are performed to increase the efficiency of commercial solar cells. In most of these methods, the main concept is increasing light interaction by the cell through chemical modification of the morphology of the surface. Creation of pyramid-like structure on SC surface through the chemical etching by KOH solution is the most common industrial method nowadays. Recently we proposed Nonlinear Laser Lithography (NLL) as an alternative method for the traditional chemical etching [2]. The method is based on the well known phenomenon Laser Induced Periodic Surface Structuring (LIPSS), allowing creation of wellordered, periodic ablation and/or oxidation lines on the material surface with subwavelength period under ultrashort pulse laser illumination. In comparison with the traditional chemical treatment, the method is cheap, single-step and chemically free. However, the damage of the crystalline structure of the SC surface during ablation limiting the final efficiency of the device. In the current work, we demonstrate the new achievement in the efficiency of c-Si solar cell based on NLL treated surface. By proper design of the laser parameters and the scanning geometry during the NLL process, as well as proper post-passivation of the SC surface, we demonstrate more than 16% efficiency of the final device. To the best of our knowledge, this is the highest efficiency demonstrated so far on a laser treated c-Si solar cell without any chemical texturing

Laser Induced Periodic Surface Structured c-Si Solar Cell with more than 16% efficiency

Crystalline-Si (c-Si) based solar cells (SC) efficiency remains one of the most challenging part in photovoltaic industry. Besides of the thermodynamical limits, the optical losses due to indirect band-gap structure of the material require additional treatment which known as a photonic design of the SC surface [1]. Numerous manipulations are performed to increase the efficiency of commercial solar cells. In most of these methods, the main concept is increasing light interaction by the cell through chemical modification of the morphology of the surface. Creation of pyramid-like structure on SC surface through the chemical etching by KOH solution is the most common industrial method nowadays. Recently we proposed Nonlinear Laser Lithography (NLL) as an alternative method for the traditional chemical etching [2]. The method is based on the well known phenomenon Laser Induced Periodic Surface Structuring (LIPSS), allowing creation of wellordered, periodic ablation and/or oxidation lines on the material surface with subwavelength period under ultrashort pulse laser illumination. In comparison with the traditional chemical treatment, the method is cheap, single-step and chemically free. However, the damage of the crystalline structure of the SC surface during ablation limiting the final efficiency of the device. In the current work, we demonstrate the new achievement in the efficiency of c-Si solar cell based on NLL treated surface. By proper design of the laser parameters and the scanning geometry during the NLL process, as well as proper post-passivation of the SC surface, we demonstrate more than 16% efficiency of the final device. To the best of our knowledge, this is the highest efficiency demonstrated so far on a laser treated c-Si solar cell without any chemical texturing