Time-resolved cryo-EM using a combination of droplet microfluidics with on-demand jetting.

Single-particle cryogenic electron microscopy (cryo-EM) allows reconstruction of high-resolution structures of proteins in different conformations. Protein function often involves transient functional conformations, which can be resolved using time-resolved cryo-EM (trEM). In trEM, reactions are arrested after a defined delay time by rapid vitrification of protein solution on the EM grid. Despite the increasing interest in trEM among the cryo-EM community, making trEM samples with a time resolution below 100 ms remains challenging. Here we report the design and the realization of a time-resolved cryo-plunger that combines a droplet-based microfluidic mixer with a laser-induced generator of microjets that allows rapid reaction initiation and plunge-freezing of cryo-EM grids. Using this approach, a time resolution of 5 ms was achieved and the protein density map was reconstructed to a resolution of 2.1 Å. trEM experiments on GroEL:GroES chaperonin complex resolved the kinetics of the complex formation and visualized putative short-lived conformations of GroEL-ATP complex.

Completeness of total mesorectum excision of laparoscopic versus robotic surgery: a review with a meta-analysis.

BACKGROUND: TME has revolutionized the surgical management of rectal cancer, and since the introduction of robotic TME (RTME), many reports have shown the feasibility and the safety of this approach. However, concerns persist regarding the advantages of robotic in surgery for the completeness of TME. The aim of this review is to compare robotic versus laparoscopic total mesorectal excision (TME) in rectal cancer, focusing on the completeness of TME. METHODS: A systematic search was performed in the electronic databases for all available studies comparing RTME versus conventional laparoscopic LTME with declared grade of mesorectum excision. Data regarding sample size, clinical and demographic characteristics, number of complete, nearly complete, and incomplete TME were extracted. Primary outcome was the number of complete TME in robotic and laparoscopic procedures. Secondary outcomes were the numbers of nearly complete and incomplete TME in robotic and laparoscopic rectal resections. RESULTS: Twelve articles were included in the final analysis. Complete TME was reported by all authors, involving 1510 procedures, showing a significant difference in favor of robotic surgery (OR = 1.83, 95% CI 1.08-3.10, p = 0.03). Nearly complete and incomplete TME showed no significant difference between the procedures. Meta-regression analysis showed that none of patients' and tumors' characteristics significantly impacted on complete TME. CONCLUSIONS: Our results underline that the robotic approach to rectal resection is the better way to obtain a complete TME. However, it is mandatory that randomized clinical trials should be performed to assess definitively if robotic minimally invasive surgery is better than a laparoscopic resection.

A Microfluidic Approach for Inducing Cell Rotation by Means of Hydrodynamic Forces.

Microfluidic technology allows to realize devices in which cells can be imaged in their three-dimensional shape. However, there are still some limitations in the method, due to the fact that cells follow a straight path while they are flowing in a channel. This can result in a loss in information, since only one side of the cell will be visible. Our work has started from the consideration that if a cell rotates, it is possible to overcome this problem. Several approaches have been proposed for cell manipulation in microfluidics. In our approach, cells are controlled by only taking advantages of hydrodynamic forces. Two different devices have been designed, realized, and tested. The first device induces cell rotation in a plane that is parallel (in-plane) to the observation plane, while the second one induce rotation in a plane perpendicular (out-of-plane) to the observation plane.