다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

Surface topographical factors influencing bacterial attachment

Erratum : An Overview of Injectable Polymeric Hydrogels for Tissue Engineering

In it for the long haul: Clusters of Pt nanowires (3D Pt nanoassemblies, Pt NA) serve as an electrocatalyst for low-temperature fuel cells. These Pt nanoassemblies exhibit remarkably high stability following thousands of voltage cycles and good catalytic activity, when compared with a commercial Pt catalyst and 20 % wt Pt catalyst supported on carbon black (20 % Pt/CB).

Self-Supported Interconnected Pt Nanoassemblies as Highly Stable Electrocatalysts for Low-Temperatur

While the bulk of the finished microbial genomes sequenced to date are derived from cultured bacterial and archaeal representatives, the vast majority of microorganisms elude current culturing attempts, severely limiting the ability to recover complete or even partial genomes from these environmental species. Single cell genomics is a novel culture-independent approach, which enables access to the genetic material of an individual cell. No single cell genome has to our knowledge been closed and finished to date. Here we report the completed genome from an uncultured single cell of Candidatus Sulcia muelleri DMIN. Digital PCR on single symbiont cells isolated from the bacteriome of the green sharpshooter Draeculacephala minerva bacteriome allowed us to assess that this bacteria is polyploid with genome copies ranging from approximately 200-900 per cell, making it a most suitable target for single cell finishing efforts. For single cell shotgun sequencing, an individual Sulcia cell was isolated and whole genome amplified by multiple displacement amplification (MDA). Sanger-based finishing methods allowed us to close the genome. To verify the correctness of our single cell genome and exclude MDA-derived artifacts, we independently shotgun sequenced and assembled the Sulcia genome from pooled bacteriomes using a metagenomic approach, yielding a nearly identical genome. Four variations we detected appear to be genuine biological differences between the two samples. Comparison of the single cell genome with bacteriome metagenomic sequence data detected two single nucleotide polymorphisms (SNPs), indicating extremely low genetic diversity within a Sulcia population. This study demonstrates the power of single cell genomics to generate a complete, high quality, non-composite reference genome within an environmental sample, which can be used for population genetic analyzes.

One Bacterial Cell, One Complete Genome

Physical introduction of foreign biomolecules such as genes, proteins, DNA and RNA into living cells with high efficiency is a challenging task for biological and therapeutic research. Bulk electroporation technique, where high electric field pulses were applied to millions of cells together in-between two large electrodes, though widely employed, however is nonspecific resulting in variable efficiency with low cell viability. Here we demonstrate controllable nano-electroporation platform for HeLa cell and human Caucasian Gastric Adenocarcinoma (AGS) cell to achieve high efficient bimolecular delivery with high cell viability. Our system consists of 40nm triangular Indium Tin Oxide (ITO) metal tip with 60nm electrode gap to provide high intense electric filed into the local region of the single cell membrane. Therefore biomolecules can be delivered by much enhance electrophoresis and diffusion effects during pulsing process through a small specific nano-region of the single cell, where remaining other area of the cell membrane unaffected. This microfluidic device has great ability to offer spatial, temporal and qualitative dosage control as well as very high transfection efficiency and high cell viability.

http://ieeexplore.ieee.org/iel7/6749560/6765550/06765778.pdf

Nanoelectroporation and controllable intracellular delivery into localized single cell with high transfection and cell viability

The present invention disclosed a nano-electrode based transparent chip, which is applicable to perform a micro fluidic substance diffused through a specific region of a single cell membrane by localized electroporation technique with membrane reversibility. The chip comprises a silicon-based layer, different structural layers, an insulating layer and a micro fluidic layer. When the individual single cell was placed on the gap between a plurality of triangular-shaped nano-electrodes with nano-tip, then electric field can intense on a specific region of the individual single cell causes the formation of nano-pores on the membrane, resulting to deliver drugs, DNA molecules from outside of the cell to the inside of the cell with a high transfection rate and a high cell viability. This technique not only generates well-controlled nano-pores to allow rapid recovery of the cell membrane, but also provides clear optical path for potentially monitoring/tracing the drugs into the cell.

Nano-electrode based chip

© 2014 IEEE. Today single cell research is a great interest to analyze cell to cell or cell to environment behavior with their intracellular compounds, where bulk measurement can provide average value. To deliver biomolecules precise and localized way into single living cell with high transfection rate and high cell viability is a challenging and promisible task for biological and therapeutic research. In this report, we present a nano-localized single cell nano-electroporation technique, where electroporation take place in a very precise and localized area on a single cell membrane to achieve high efficient delivery with high cell viability. We fabricated 60nm gap with 40 nm triangular Indium Tin Oxide (ITO) based nano-eletcrode tip, which can intense electric field in a nano-localized area of a single cell to permeabilize cell membrane and deliver exogenous biomolecules from outside to inside of the cell. This device successfully deliver dyes, proteins into single cell with high cell viability (98%). The process not only control precise delivery mechanism into single cell with membrane reversibility, but also it can provide special, temporal and qualitative dosage control, which might be beneficial for therapeutic and biological cell studies.

Nanolocalized single cell membrane nanoelectroporation

Light-Induced Cellular Delivery and Analysis

Temperature governs the reactivity of a wide range of biomolecules in the cellular environment dynamically. The complex cellular pathways and molecules in solid tumors substantially produce temperature gradients in the tumor microenvironment (TME). Hence, visualization of these temperature gradients at the cellular level would give physiologically relevant spatio-temporal information about solid tumors. This study used fluorescent polymeric nano-thermometers (FPNTs) to measure the intratumor temperature in co-cultured 3D tumor spheroids. A temperature-sensitive rhodamine-B dye and Pluronic F-127 were conjugated through hydrophobic and hydrophobic interactions and then cross-linked with urea-paraformaldehyde resins to form the FPNTs. The characterization results exhibit monodisperse nanoparticles (166 ± 10 nm) with persistent fluorescence. The FPNTs exhibit a linear response with a wide temperature sensing range (25-100 °C) and are stable toward pH, ionic strength, and oxidative stress. FPNTs were utilized to monitor the temperature gradient in co-cultured 3D tumor spheroids and the temperature difference between the core (34.9 °C) and the periphery (37.8 °C) was 2.9 °C. This investigation demonstrates that the FPNTs have great stability, biocompatibility, and high intensity in a biological medium. The usage of FPNTs as a multifunctional adjuvant may demonstrate the dynamics of the TME and they may be suitable candidates to examine thermoregulation in tumor spheroids.

Synthesis and characterization of a fluorescent polymeric nano-thermometer: dynamic monitoring of 3D temperature distribution in co-cultured tumor spheroids.

Tuhin Subhra Santra

Papers

Nanoelectroporation and controllable intracellular delivery into localized single cell with high transfection and cell viability

Nano-electrode based chip

Nanolocalized single cell membrane nanoelectroporation

Light-Induced Cellular Delivery and Analysis

Synthesis and characterization of a fluorescent polymeric nano-thermometer: dynamic monitoring of 3D temperature distribution in co-cultured tumor spheroids.