Pathologies related to the cardiovascular system are the leading causes of death worldwide. One of the main treatments is conventional surgery with autologous transplants. Although donor grafts are often unavailable, tissue-engineered vascular grafts (TEVGs) show promise for clinical treatments. A systematic review of the recent scientific literature was performed using PubMed (Medline) and Web of Science databases to provide an overview of the state-of-the-art in TEVG development. The use of TEVG in human patients remains quite restricted owing to the presence of vascular stenosis, existence of thrombi, and poor graft patency. A total of 92 original articles involving human patients and animal models were analyzed. A meta-analysis of the influence of the vascular graft diameter on the occurrence of thrombosis and graft patency was performed for the different models analyzed. Although there is no ideal animal model for TEVG research, the murine model is the most extensively used. Hybrid grafting, electrospinning, and cell seeding are currently the most promising technologies. The results showed that there is a tendency for thrombosis and non-patency in small-diameter grafts. TEVGs are under constant development, and research is oriented towards the search for safe devices.

Objective: The objective of this study is to compare the use of three-dimensional (3D) vision systems with traditional two-dimensional systems in laparoscopic urological surgery, analyzing the benefits, limitations, and impact of introducing this medical technology with regard to surgical performance and the surgeon's ergonomics. Methods: A systematic review with a structured bibliographic search was conducted in the electronic libraries (PubMed and EMBASE) until August 2019 and with no language restrictions. Studies on 3D visualization technology in laparoscopic urologic surgery, randomized controlled trials, and observational comparative studies were included. Relevant data were extracted and analyzed. Results: A total of 25 articles were obtained, of which 4 were clinical studies with patients, 2 studies were carried out in experimental animal models, and the remaining 19 were conducted in simulated environments. Regarding the European training program in basic laparoscopic urological skills, the results showed no significant differences in execution time using either imaging system. Three-dimensional vision led to a significant reduction in surgery time in pyeloplasty and radical nephrectomy. In addition, there was a reported decrease in blood loss in adrenalectomy, nephron-sparing nephrectomy, radical nephrectomy, simple nephrectomy, and pyeloplasty using 3D vision. Regarding ergonomics, the studies generally described no differences in side effects (headache, nausea, eye strain) when comparing the two types of visualization systems. Surgeons reported reduced workloads and stress with 3D vision than with traditional laparoscopy. Conclusions: Three-dimensional laparoscopic systems essentially advance surgical performance in lessexperienced laparoscopic surgeons. Three-dimensional laparoscopy leads to improvements in surgery time, which is important for specific surgical procedures involving intracorporeal ligatures and sutures. The results achieved on the surgeons' ergonomics showed better depth perception and decreased stress and workloads during 3D vision with no differences in potential side effects.

Silk fibroin (SF) is a biocompatible natural protein with excellent mechanical characteristics. SF-based biomaterials can be structured using a number of techniques, allowing the tuning of materials for specific biomedical applications. In this study, SF films, porous membranes, and electrospun membranes were produced using solventcasting, salt-leaching, and electrospinning methodologies, respectively. SFbased materials were subjected to physicochemical and biological characterizations to determine their suitability for tissue regeneration applications. Mechanical analysis showed stress−strain curves of brittle materials in films and porous membranes, while electrospun membranes featured stress−strain curves typical of ductile materials. All samples showed similar chemical composition, melting transition, hydrophobic behavior, and low cytotoxicity levels, regardless of their architecture. Finally, all of the SF-based materials promote the proliferation of human umbilical vein endothelial cells (HUVECs). These findings demonstrate the different relationship between HUVEC behavior and the SF sample's topography, which can be taken advantage of for the design of vascular implants.

Tissue engineering (TE) aims to develop structures that improve or even replace the biological functions of tissues and organs. Mechanical properties, physical-chemical characteristics, biocompatibility, and biological performance of the materials are essential factors for their applicability in TE. Poly(vinylidene fluoride) (PVDF) is a thermoplastic polymer that exhibits good mechanical properties, high biocompatibility and excellent thermal properties. However, PVDF structuring, and the corresponding processing methods used for its preparation are known to significantly influence these characteristics.In this study, doctor blade, salt-leaching, and electrospinning processing methods were used to produce PVDF-based structures in the form of films, porous membranes, and fiber scaffolds, respectively. These PVDF scaffolds were subjected to a variety of characterizations and analyses, including physicochemical analysis, contact angle measurement, cytotoxicity assessment and cell proliferation.All prepared PVDF scaffolds are characterized by a mechanical response typical of ductile materials. PVDF films displayed mostly vibration modes for the a-phase, while the remaining PVDF samples were characterized by a higher content of electroactive β-phase due the low temperature solvent evaporation during processing. No significant variations have been observed between the different PVDF membranes with respect to the melting transition. In addition, all analysed PVDF samples present a hydrophobic behavior. On the other hand, cytotoxicity assays confirm that cell viability is maintained independently of the architecture and processing method. Finally, all the PVDF samples promote human umbilical vein endothelial cells (HUVECs) proliferation, being higher on the PVDF film and electrospun randomly-oriented membranes. These findings demonstrated the importance of PVDF topography on HUVEC behavior, which can be used for the design of vascular implants.