scholarly journals On-Chip Inverted Emulsion Method for Fast Giant Vesicle Production, Handling, and Analysis

Micromachines ◽  
2020 ◽  
Vol 11 (3) ◽  
pp. 285 ◽  
Author(s):  
Naresh Yandrapalli ◽  
Tina Seemann ◽  
Tom Robinson
Keyword(s):  
Microfluidic Chip ◽  
Enzymatic Reactions ◽  
Single Chip ◽  
Artificial Cells ◽  
Observation Chamber ◽  
Emulsion Method ◽  
Solution Exchange ◽  
Fast Solution ◽  
On Chip ◽  
Single Batch

Liposomes and giant unilamellar vesicles (GUVs) in particular are excellent compartments for constructing artificial cells. Traditionally, their use requires bench-top vesicle growth, followed by experimentation under a microscope. Such steps are time-consuming and can lead to loss of vesicles when they are transferred to an observation chamber. To overcome these issues, we present an integrated microfluidic chip which combines GUV formation, trapping, and multiple separate experiments in the same device. First, we optimized the buffer conditions to maximize both the yield and the subsequent trapping of the vesicles in micro-posts. Captured GUVs were monodisperse with specific size of 18 ± 4 µm in diameter. Next, we introduce a two-layer design with integrated valves which allows fast solution exchange in less than 20 s and on separate sub-populations of the trapped vesicles. We demonstrate that multiple experiments can be performed in a single chip with both membrane transport and permeabilization assays. In conclusion, we have developed a versatile all-in-one microfluidic chip with capabilities to produce and perform multiple experiments on a single batch of vesicles using low sample volumes. We expect this device will be highly advantageous for bottom-up synthetic biology where rapid encapsulation and visualization is required for enzymatic reactions.

scholarly journals Microfluidic Flow-through SPME Chip for Online Separation and MS Detection of Multiple Analyses in Complex Matrix

Micromachines ◽  
2020 ◽  
Vol 11 (2) ◽  
pp. 120
Author(s):  
Yujun Chen ◽  
Tao Gong ◽  
Cilong Yu ◽  
Xiang Qian ◽  
Xiaohao Wang
Keyword(s):  
Microfluidic Chip ◽  
Solid Phase Microextraction ◽  
Solid Phase ◽  
Sample Pretreatment ◽  
Annular Channel ◽  
Calibration Method ◽  
Extraction Process ◽  
Single Chip ◽  
Calibration Methods ◽  
On Chip

Simplifying tedious sample preparation procedures to improve analysis efficiency is a major challenge in contemporary analytical chemistry. Solid phase microextraction (SPME), a technology developed for rapid sample pretreatment, has flexibility in design, geometry, and calibration strategies, which makes it a useful tool in a variety of fields, especially environmental and life sciences. Therefore, it is important to study the coupling between the microfluidic electrospray ionization (ESI) chip integrated with the solid phase microextraction (SPME) module and the electrospray mass spectrometer (MS). In our previous work, we designed a solid phase microextraction (SPME) module on a microfluidic chip through geometric design. However, automation and calibration methods for the extraction process remain unresolved in the SPME on-chip domain, which will lead to faster and more accurate results. This paper discusses the necessity to design a micromixer structure that can produce different elution conditions on the microfluidic chip. By calculating the channel resistances, the microfluidic chip’s integrated module with the micromixer, SPME, and ESI emitters optimize the geometry structure. We propose the annular channel for SPME to perform the resistances balance of the entire chip. Finally, for SPME on a single chip, this work provides a quantitation calibration method to describe the distribution of the analytes between the sample and the extraction phase before reaching the adsorption equilibrium.

scholarly journals Smart Integrated Sensor for Multiple Detections of Glucose and L-Lactate Using On-Chip Electrochemical System

2011 ◽  
Vol 2011 ◽  
pp. 1-7 ◽  
Author(s):  
Tomoyuki Yamazaki ◽  
Takaaki Ikeda ◽  
Byounghyun Lim ◽  
Koichi Okumura ◽  
Makoto Ishida ◽  
...  
Keyword(s):  
Point Of Care ◽  
Reference Electrode ◽  
Electrochemical Sensing ◽  
Quantitative Detection ◽  
Enzymatic Reactions ◽  
Single Chip ◽  
Lactate Oxidase ◽  
Integrated Sensor ◽  
System L ◽  
On Chip

Multiple sensor electrodes, a supplementary electrode, a reference electrode, and signal-processing circuits were integrated on a single chip to develop a chip-shaped electrochemical sensing system. L-lactate and glucose were measured using on-chip working electrodes modified by polyion complex to immobilize lactate oxidase and glucose oxidase, respectively. Cyclic voltammetry measurements were conducted using an on-chip potentiostat. Selective and quantitative detection of glucose and L-lactate and the interference behavior were studied. Hydrogen peroxide generated by enzymatic reactions was detected by an increase in anodic oxidation current. Reaction currents at +0.7 V versus Ag/AgCl were used to obtain calibration plots. The measured dynamic ranges for L-lactate and glucose were 0.2–1.0 mM and 2.0–8.0 mM, respectively. The sensitivities were 65 nA/mM and 15 nA/mM, respectively, using a working electrode of 0.5 mm2. The 3σdetection limit was 0.19 mM and 1.1 mM, respectively. We have achieved multiple biomaterial detections on a circuit-equipped single chip. This integrated electrochemical sensor chip could be the best candidate for realizing point-of-care testing due to its portability and potential for mass production.

scholarly journals Design and Fabrication of Multichannel PDMS Microfluidic

2021 ◽  
Vol 2129 (1) ◽  
pp. 012048
Author(s):  
M N Afnan Uda ◽  
U Hashim ◽  
M N A Uda ◽  
N A Parmin ◽  
V Thivina
Keyword(s):  
Contact Area ◽  
Microfluidic Chip ◽  
Point Of Care ◽  
Main Tool ◽  
Morphological Properties ◽  
Single Chip ◽  
Lab On Chip ◽  
Micro Channels ◽  
On Chip ◽  
Disease Analysis

Abstract Microfluidic delivers miniaturized fluidic networks for processing liquids in the microliter range. In the recent years, lab-on-chip (LOC) is become a main tool for point-of-care (POC) diagnostic especially in the medical field. In this paper, we presented a design and fabrication on multi disease analysis using single chip via delivery of fluid with the multiple transducers is the pathway of multi-channel microfluidic based LOC’s. 3 in 1 nano biosensor kit was attached with the microfluidic to produce nano-biolab-on-chip (NBLOC). The multi channels microfluidic chip was designed including the micro channels, one inlet, three outlet and sensor contact area. The microfluidic chip was designed to include multiplex detection for pathogen that consists of multiple channels of simultaneous results. The LOC system was designed using Design Spark Mechanical software and PDMS was used as a medium of the microfluidic. The microfluidic mold and PDMS microfluidic morphological properties have been characterized by using low power microscope (LPM), high power microscope (HPM) and surface profiler. The LOC system physical was experimental by dropping food coloring through the inlet and collecting at the sensor contact area outlet.

A Study of On-Chip Aqueous Two Phase System Formation and its Applications

2012 ◽  
Author(s):  
Pavithra A. L. Wijethunga ◽  
Hyejin Moon
Keyword(s):  
Microfluidic Chip ◽  
Biological Sample ◽  
Gravitational Force ◽  
Phase System ◽  
Single Chip ◽  
Two Phase ◽  
Micro Scale ◽  
Macro Scale ◽  
Two Phases ◽  
On Chip

Although there are several reports demonstrating the use of aqueous two-phase systems (ATPS) for biological sample separation in miniaturized devices, they only used ATPS prepared in macro scale by following the conventional way. Formation of ATPS in a confined micro scale environment and their characteristics has not been studied yet. While ATPS formation in macro scale is supported by vigorous mixing and gravitational force to form two phases, both mixing capability and gravitational force aid are insignificant in micro scale. Hence, in this study, we investigated the formation of ATPS under these inferior conditions of micro scale. An electrowetting on a dielectric (EWOD) digital microfluidic chip was used as the confined miniaturized environment. In an EWOD device, micro/nano scale droplets are manipulated on an array of electrodes by sequential application of voltages to the electrodes. The common polyethylene glycol (PEG) and dextran (DEX) polymer/polymer ATPS was used as the model system. Nanoliter volume droplets of the two pure polymer solutions were brought into contact, mixed, and successfully formed ATPS on an EWOD chip. Furthermore, it was possible to separate the two phases into two droplets, demonstrating the promising capability of on-chip biological sample separations effectively by integrating formation of ATPS and separation process using ATPS in a single chip. This study also compares the characteristics of ATPS generated in microfluidic chip with that generated in conventional macro scale. The effect of mixing performance on the ATPS formation is studied experimentally.

scholarly journals A Survey of Software-Defined Networks-on-Chip: Motivations, Challenges and Opportunities

Micromachines ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 183
Author(s):  
Jose Ricardo Gomez-Rodriguez ◽  
Remberto Sandoval-Arechiga ◽  
Salvador Ibarra-Delgado ◽  
Viktor Ivan Rodriguez-Abdala ◽  
Jose Luis Vazquez-Avila ◽  
...  
Keyword(s):  
Single Chip ◽  
Synthesis Time ◽  
Networks On Chip ◽  
Data Dependencies ◽  
Layered Architecture ◽  
Systems On Chip ◽  
Challenges And Opportunities ◽  
Computing Platforms ◽  
On Chip ◽  
Many Core

Current computing platforms encourage the integration of thousands of processing cores, and their interconnections, into a single chip. Mobile smartphones, IoT, embedded devices, desktops, and data centers use Many-Core Systems-on-Chip (SoCs) to exploit their compute power and parallelism to meet the dynamic workload requirements. Networks-on-Chip (NoCs) lead to scalable connectivity for diverse applications with distinct traffic patterns and data dependencies. However, when the system executes various applications in traditional NoCs—optimized and fixed at synthesis time—the interconnection nonconformity with the different applications’ requirements generates limitations in the performance. In the literature, NoC designs embraced the Software-Defined Networking (SDN) strategy to evolve into an adaptable interconnection solution for future chips. However, the works surveyed implement a partial Software-Defined Network-on-Chip (SDNoC) approach, leaving aside the SDN layered architecture that brings interoperability in conventional networking. This paper explores the SDNoC literature and classifies it regarding the desired SDN features that each work presents. Then, we described the challenges and opportunities detected from the literature survey. Moreover, we explain the motivation for an SDNoC approach, and we expose both SDN and SDNoC concepts and architectures. We observe that works in the literature employed an uncomplete layered SDNoC approach. This fact creates various fertile areas in the SDNoC architecture where researchers may contribute to Many-Core SoCs designs.

Glycan chip based on structure switchable DNA linker for on-chip biosynthesis of cancer-associated complex glycans

2021 ◽  
Author(s):  
Hye Ryoung Heo ◽  
Kye Il Joo ◽  
Jeong Hyun Seo ◽  
Chang Sup Kim ◽  
Hyung Joon Cha
Keyword(s):  
Breast Cancer Cells ◽  
Enzymatic Reactions ◽  
Dependent Manner ◽  
Ph Responsive ◽  
Quantitative Analyses ◽  
Ph Dependent ◽  
Complex Glycans ◽  
On Chip ◽  
Complex Glycan ◽  
Mcf 7

Abstract On-chip glycan biosynthesis is an effective strategy for preparing useful complex glycan sources and for preparing glycan-involved applications simultaneously. However, current methods have some limitations when analyzing biosynthesized glycans and optimizing enzymatic reactions, which could result in undefined glycan structures on a surface, leading to unequal and unreliable results. In this work, a novel glycan chip was developed by introducing a pH-responsive i-motif DNA linker to control the immobilization and isolation of glycans on chip surfaces in a pH-dependent manner. On-chip enzymatic glycosylations were optimized for uniform biosynthesis of cancer-associated Globo H hexasaccharide and its related complex glycans through stepwise quantitative analyses of isolated products from the surface. Successful interaction analyses of the anti-Globo H antibody and MCF-7 breast cancer cells with on-chip biosynthesized Globo H-related glycans demonstrated the feasibility of the structure-switchable DNA linker-based glycan chip platform for on-chip complex glycan biosynthesis and glycan-involved applications.

Desensitization and resensitization rates of glutamate-activated channels may regulate motoneuron excitability

1991 ◽  
Vol 66 (4) ◽  
pp. 1166-1175 ◽  
Author(s):  
D. O. Smith ◽  
C. Franke ◽  
J. L. Rosenheimer ◽  
F. Zufall ◽  
H. Hatt
Keyword(s):  
Ampa Receptors ◽  
Single Channel ◽  
Kainate Receptors ◽  
Whole Cell ◽  
Solution Exchange ◽  
Channel Opening ◽  
Fast Solution ◽  
Agonist Concentration ◽  
Kinetics Of ◽  
Channel Properties

1. Single-channel properties of desensitizing glutamate-activated channels were analyzed in outside-out patch-clamp recordings from a motoneuron-enriched cell fraction from embryonic chick. A piezo-driven device was used to achieve fast solution exchange at the electrode tip, resulting in maximum activation within 2 ms. 2. Quisqualate/AMPA receptors, with a 13-pS conductance, desensitized rapidly; the desensitization rate depended on agonist concentration but not on membrane potential. When quisqualate was applied slowly, the quisqualate-activated channels desensitized without prior channel opening, indicating desensitization from the closed state. After a 10-ms refractory period, resensitization of all channels required up to 300 ms; resensitization rate did not depend on the duration of the preceding quisqualate application. 3. At agonist concentrations less than or equal to 1 mM, kainate receptors, with a 20-pS conductance, did not desensitize. At kainate concentrations greater than or equal to 1 mM, though, kainate receptors desensitized to a low steady-state conductance within approximately 200 ms. Resensitization of all channels required as long as 3 s, which could render kainate receptors inexcitable during high-frequency activation. 4. Desensitization rates of whole-cell currents were similar to those observed in outside-out mode. Glutamate- and quisqualate-activated responses were similar, suggesting that the rapidly desensitizing quisqualate-sensitive receptor type may dominate the kinetics of whole-cell excitatory postsynaptic currents (EPSCs) in this preparation. 5. It may be concluded that the efficacy of glutamate-mediated synaptic transmission is modulated by differences in the rates of desensitization and resensitization.

scholarly journals Synchrony and pattern formation of coupled genetic oscillators on a chip of artificial cells

2017 ◽  
Vol 114 (44) ◽  
pp. 11609-11614 ◽  
Author(s):  
Alexandra M. Tayar ◽  
Eyal Karzbrun ◽  
Vincent Noireaux ◽  
Roy H. Bar-Ziv
Keyword(s):  
Pattern Formation ◽  
Large Scale ◽  
Reaction Diffusion ◽  
Biochemical Networks ◽  
Artificial Cells ◽  
Diffusion Dynamics ◽  
Oscillatory Reactions ◽  
Potential Applications ◽  
On Chip ◽  
Genetic Oscillators

Understanding how biochemical networks lead to large-scale nonequilibrium self-organization and pattern formation in life is a major challenge, with important implications for the design of programmable synthetic systems. Here, we assembled cell-free genetic oscillators in a spatially distributed system of on-chip DNA compartments as artificial cells, and measured reaction–diffusion dynamics at the single-cell level up to the multicell scale. Using a cell-free gene network we programmed molecular interactions that control the frequency of oscillations, population variability, and dynamical stability. We observed frequency entrainment, synchronized oscillatory reactions and pattern formation in space, as manifestation of collective behavior. The transition to synchrony occurs as the local coupling between compartments strengthens. Spatiotemporal oscillations are induced either by a concentration gradient of a diffusible signal, or by spontaneous symmetry breaking close to a transition from oscillatory to nonoscillatory dynamics. This work offers design principles for programmable biochemical reactions with potential applications to autonomous sensing, distributed computing, and biomedical diagnostics.

On-chip cavity-enhanced absorption spectroscopy using a white light-emitting diode and polymer mirrors

Lab on a Chip ◽  
2015 ◽  
Vol 15 (3) ◽  
pp. 711-717 ◽  
Author(s):  
Cathy M. Rushworth ◽  
Gareth Jones ◽  
Martin Fischlechner ◽  
Emma Walton ◽  
Hywel Morgan
Keyword(s):  
Absorption Spectroscopy ◽  
White Light ◽  
Microfluidic Chip ◽  
Path Length ◽  
Light Emitting Diode ◽  
Absorption Path Length ◽  
Light Emitting ◽  
Enhanced Absorption ◽  
Cavity Enhanced Absorption Spectroscopy ◽  
On Chip

We have integrated disposable polymer mirrors within a microfluidic chip to form a multi-pass cell, which increases the absorption path length by a maximum of 28 times, providing micromolar detection limits in a probed volume of 10 nL.

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