One-Step Microfluidic Synthesis of Nanocomplex with Tunable Rigidity and Acid-Switchable Surface Charge for Overcoming Drug Resistance

Small ◽  
2016 ◽  
Vol 13 (9) ◽  
pp. 1603109 ◽  
Author(s):  
Qiang Feng ◽  
Jianping Liu ◽  
Xuanyu Li ◽  
Qinghua Chen ◽  
Jiashu Sun ◽  
...  
Keyword(s):  
Drug Resistance ◽  
Surface Charge ◽  
One Step

scholarly journals Drug Delivery: One-Step Microfluidic Synthesis of Nanocomplex with Tunable Rigidity and Acid-Switchable Surface Charge for Overcoming Drug Resistance (Small 9/2017)

Small ◽  
2017 ◽  
Vol 13 (9) ◽  
Author(s):  
Qiang Feng ◽  
Jianping Liu ◽  
Xuanyu Li ◽  
Qinghua Chen ◽  
Jiashu Sun ◽  
...  
Keyword(s):  
Drug Delivery ◽  
Drug Resistance ◽  
Surface Charge ◽  
One Step

scholarly journals Direct dilution of cell aliquot for high temporal resolution bacterial surface charge measurement

2015 ◽  
Author(s):  
Wenfa Ng ◽  
Yen-Peng Ting
Keyword(s):  
Cell Surface ◽  
Sample Preparation ◽  
Surface Charge ◽  
Temporal Resolution ◽  
Gold Standard ◽  
Preparation Technique ◽  
Dilution Factor ◽  
Error Type ◽  
Bacterial Surface ◽  
One Step

Bacterial surface charge (SC) mediates important cell-environment and microbe-host interactions, and its accurate and precise measurement by microelectrophoresis requires removing metabolites adhered to the cell surface - where repeated centrifugation and washing by buffers is the gold standard method. Unfortunately, the need for time-consuming centrifugation limits the temporal resolution of sampling and interrogation of experimental dynamics; especially for samples requiring immediate treatment post sampling. Herein, the feasibility of diluting cell aliquots with buffer as a one-step sample preparation technique for SC measurement was investigated by characterising the effects of dilution factor, type of cation, and buffer conductivity on measuring SC of Escherichia coli DH5α grown in LB medium. Results indicated that dilution factor was critical to accurate SC measurement since low signal-to-noise ratios in high or low cell concentration samples generated substantial error. Type of buffer cation was also important since putative binding of high affinity cations to the cell surface underestimated SC of negatively-charged bacteria. Finally, although high conductivity buffers enabled greater removal of adsorbed metabolites through increased charge screening, a broader statistical distribution of measured SC was also observed – which, at extreme conductivity values, led to inaccurate data, probably due to removal of both intrinsic cell surface ions and exogenous adsorbed metabolites. Altogether, one-step dilution of cell aliquot with deionized water reliably reproduced E. coli SC values obtained via the gold standard approach; however, since the ensemble of secreted metabolites is bacteria/medium specific, distinct diluent and optimal parameters exist for each system. The described methodology may find use in preparing samples for cell surface characterisation studies, where it would help reduce sample preparation time – and thus, improve temporal resolution at which scientific questions can be probed and answered.

scholarly journals Direct dilution of cell aliquot for high temporal resolution bacterial surface charge measurement

2016 ◽  
Author(s):  
Wenfa Ng ◽  
Yen-Peng Ting
Keyword(s):  
Cell Surface ◽  
Sample Preparation ◽  
Surface Charge ◽  
Temporal Resolution ◽  
Gold Standard ◽  
Preparation Technique ◽  
Dilution Ratio ◽  
Bacterial Surface ◽  
Charge Measurement ◽  
One Step

Bacterial surface charge mediates important cell-environment and microbe-host interactions, and its accurate and precise measurement by microelectrophoresis requires removing metabolites adhered to the cell surface - where repeated centrifugation and washing by buffers is the gold standard sample preparation method. Unfortunately, the need for time-consuming centrifugation limits the temporal resolution of sampling and profiling of experimental dynamics; especially for samples requiring immediate treatment after sampling. Herein, the feasibility of diluting cell aliquots with buffer as a one step sample preparation technique for surface charge measurement was investigated by characterizing the effects of dilution ratio, cation type, and buffer conductivity on measuring surface charge of Escherichia coli DH5α (ATCC 53868) grown in LB Lennox medium. Results indicated that dilution ratio was critical to accurate surface charge measurement since low signal-to-noise ratio in high or low cell concentration samples generated substantial error. Type of buffer cation was also important since putative binding of high affinity cations to the cell surface underestimated surface charge of negatively charged bacteria. Finally, high conductivity buffers enabled greater removal of adsorbed metabolites through increased charge screening. However, a broader statistical distribution of measured surface charge was also observed – which, at extreme conductivity values, led to inaccurate data; probably due to removal of both intrinsic cell surface ions and exogenous adsorbed metabolites. Altogether, one step dilution of cell aliquot with deionized water reliably reproduced E. coli surface charge values obtained via the gold standard approach. But, since the ensemble of secreted metabolites is bacteria and/or medium specific, distinct diluent and experiment parameters exist for each system. The described methodology may find use in preparing samples for cell surface characterization studies, where it would help reduce sample preparation time – and thus, improve temporal resolution at which scientific questions can be probed and answered.

Design and construction of self-hidden and pH-reversed targeting drug delivery nanovehicles via noncovalent interactions to overcome drug resistance

2017 ◽  
Vol 5 (15) ◽  
pp. 2823-2831 ◽  
Author(s):  
Dan Zhao ◽  
Xiaoqing Yi ◽  
Jiaqi Xu ◽  
Gongdao Yuan ◽  
Renxi Zhuo ◽  
...  
Keyword(s):  
Drug Delivery ◽  
Drug Resistance ◽  
Noncovalent Interactions ◽  
Step Method ◽  
Construction Of Self ◽  
One Step ◽  
Design And Construction

A convenient one-step method was used to construct self-hidden and pH-reversed targeting drug delivery nanovehicles using the host–guest interaction between β-CD and Ad, and borate formation between PBA and serinol.

One-Step Silicon Nitride Passivation by ECR-CVD for Heterostructure Transistors and MIS Devices

1999 ◽  
Vol 573 ◽  
Author(s):  
J. A. Diniz ◽  
L. E. M. de Barros ◽  
R. T. Yoshioka ◽  
G. S. Lujan ◽  
I. Danilov ◽  
...  
Keyword(s):  
Silicon Nitride ◽  
Surface Charge ◽  
Surface Characterization ◽  
Electron Cyclotron Resonance ◽  
Chemical Vapor ◽  
Sample Surface ◽  
Charge Densities ◽  
One Step ◽  
Pre Treatment ◽  
Mis Devices

ABSTRACTSilicon nitride (SiNx) films with extremely low interface charge densities have been developed by electron cyclotron resonance-chemical vapor deposition (ECR-CVD) deposition on GaAs substrates. The procedure is a one-step process and does not involve H2 and/or N2 pre-treatment of the sample surface. Characterization by Fourier transform infrared (FTIR) and ellipsometry analysis indicate good properties of the film revealing N-H and Si-N bonds. Results of capacitance-voltage (C–V) measurements show surface charge densities on the order of 5 × 1010 cm−2, which we believe is the lowest surface charge density achieved so far over GaAs.

scholarly journals Direct dilution of cell aliquot for high temporal resolution bacterial surface charge measurement

2013 ◽  
Author(s):  
Wenfa Ng
Keyword(s):  
Cell Surface ◽  
Sample Preparation ◽  
Surface Charge ◽  
Temporal Resolution ◽  
Gold Standard ◽  
Standard Approach ◽  
Preparation Technique ◽  
Dilution Factor ◽  
Bacterial Surface ◽  
One Step

Bacterial surface charge (SC) mediates important cell-environment and microbe-host interactions, and its accurate and precise measurement by microelectrophoresis requires removing metabolites adhered to the cell surface - where repeated centrifugation and washing by buffers is the gold standard approach. Unfortunately, the need for time-consuming centrifugation limits the temporal resolution of sampling and interrogation of experimental dynamics; especially for samples requiring immediate treatment post sampling. Herein, the feasibility of diluting cell aliquots with buffer as a one-step sample preparation technique for SC measurement was investigated by characterising the effects of dilution factor, type of cation, and buffer conductivity on measuring SC of Escherichia coli DH5α grown in LB medium. Results indicated that dilution factor was critical to accurate SC measurement since low signal-to-noise ratios in high or low cell concentration samples generated substantial error. Type of buffer cation was also important since putative binding of high affinity cations to the cell surface underestimated SC of negatively-charged bacteria. Finally, although high conductivity buffers enabled greater removal of adsorbed metabolites through increased charge screening, a broader statistical distribution of measured SC was also observed – which, at extreme conductivity values, led to inaccurate data, probably due to removal of both intrinsic cell surface ions and exogenous adsorbed metabolites. Altogether, one-step dilution of cell aliquot with deionized water reliably reproduced E. coli SC values obtained via the gold standard approach; however, since the ensemble of secreted metabolites is bacteria/medium specific, distinct diluent and optimal parameters exist for each system. The described methodology may find use in preparing samples for cell surface characterisation studies, where it would help reduce sample preparation time – and thus, improve temporal resolution at which scientific questions can be probed and answered.

scholarly journals One-Step Synthesis of PEGylated Gold Nanoparticles with Tunable Surface Charge

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Rares Stiufiuc ◽  
Cristian Iacovita ◽  
Raul Nicoara ◽  
Gabriela Stiufiuc ◽  
Adrian Florea ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Surface Charge ◽  
Colloidal Stability ◽  
Spherical Shape ◽  
Average Diameter ◽  
Molecular Chain ◽  
Surface Charges ◽  
One Step

The present work reports a rapid, simple and efficient one-step synthesis and detailed characterisation of stable aqueous colloids of gold nanoparticles (AuNPs) coated with unmodified poly(ethylene)glycol (PEG) molecules of different molecular weights and surface charges. By mixing and heating aqueous solutions of PEG with variable molecular chain and gold(III) chloride hydrate (HAuCl4) in the presence of NaOH, we have successfully produced uniform colloidal 5 nm PEG coated AuNPs of spherical shape with tunable surface charge and an average diameter of 30 nm within a few minutes. It has been found out that PEGylated AuNPs provide optical enhancement of the characteristic vibrational bands of PEG molecules attached to the gold surface when they are excited with both visible (532 nm) and NIR (785 nm) laser lines. The surface enhanced Raman scattering (SERS) signal does not depend on the length of the PEG molecular chain enveloping the AuNPs, and the stability of the colloid is not affected by the addition of concentrated salt solution (0.1 M NaCl), thus suggesting their potential use forin vitroandin vivoapplications. Moreover, by gradually changing the chain length of the biopolymer, we were able to control nanoparticles’ surface charge from −28 to −2 mV, without any modification of the Raman enhancement properties and of the colloidal stability.

Treatment of drug resistance in epilepsy: one step at a time

2006 ◽  
Vol 5 (5) ◽  
pp. 380-381 ◽  
Author(s):  
Sanjay M Sisodiya ◽  
Susan E Bates
Keyword(s):  
Drug Resistance ◽  
One Step

An Interactive Minicomputer Program for the Indexing and Simulation of Electron Diffraction Patterns

1976 ◽  
Vol 34 ◽  
pp. 542-543
Author(s):  
R.P. Goehner ◽  
W.T. Hatfield ◽  
Prakash Rao
Keyword(s):  
Electron Diffraction ◽  
Real Time ◽  
Pattern Analysis ◽  
Flow Diagram ◽  
Hard Copy ◽  
Time Analysis ◽  
Real Time Analysis ◽  
Transmission Electron ◽  
One Step ◽  
Diffraction Patterns

Computer programs are now available in various laboratories for the indexing and simulation of transmission electron diffraction patterns. Although these programs address themselves to the solution of various aspects of the indexing and simulation process, the ultimate goal is to perform real time diffraction pattern analysis directly off of the imaging screen of the transmission electron microscope. The program to be described in this paper represents one step prior to real time analysis. It involves the combination of two programs, described in an earlier paper(l), into a single program for use on an interactive basis with a minicomputer. In our case, the minicomputer is an INTERDATA 70 equipped with a Tektronix 4010-1 graphical display terminal and hard copy unit.A simplified flow diagram of the combined program, written in Fortran IV, is shown in Figure 1. It consists of two programs INDEX and TEDP which index and simulate electron diffraction patterns respectively. The user has the option of choosing either the indexing or simulating aspects of the combined program.

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