scholarly journals Determining Particle Size and Position in a Coplanar Electrode Setup Using Measured Opacity for Microfluidic Cytometry

Biosensors ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 353
Author(s):  
Douwe S. de de Bruijn ◽  
Koen F. A. Jorissen ◽  
Wouter Olthuis ◽  
Albert van den van den Berg
Keyword(s):  
Particle Size ◽  
Single Cells ◽  
Channel Height ◽  
Label Free ◽  
Non Invasive ◽  
Compensation Methods ◽  
Label Free Detection ◽  
Coplanar Electrodes ◽  
Bead Height ◽  
Layer Series

Microfluidic impedance flow cytometers enable high-throughput, non-invasive, and label-free detection of single-cells. Cytometers with coplanar electrodes are easy and cheap to fabricate, but are sensitive to positional differences of passing particles, owing to the inhomogeneous electric field. We present a novel particle height compensation method, which employs the dependence of measured electrical opacity on particle height. The measured electrical opacity correlates with the particle height as a result of the constant electrical double layer series capacitance of the electrodes. As an alternative to existing compensation methods, we use only two coplanar electrodes and multi-frequency analysis to determine the particle size of a mixture of 5, 6, and 7 µm polystyrene beads with an accuracy (CV) of 5.8%, 4.0%, and 2.9%, respectively. Additionally, we can predict the bead height with an accuracy of 1.5 µm (8% of channel height) using the measured opacity and we demonstrate its application in flow cytometry with yeast. The use of only two electrodes is of special interest for simplified, easy-to-use chips with a minimum amount of instrumentation and of limited size.

Process characterization of epithelial–mesenchymal transition in alveolar epithelial type II cells using surface-enhanced Raman scattering spectroscopy

RSC Advances ◽  
2016 ◽  
Vol 6 (17) ◽  
pp. 14321-14328 ◽  
Author(s):  
Xiaowei Cao ◽  
Xiang Chen ◽  
Chaowen Shi ◽  
Mingyue Zhang ◽  
Wenbo Lu ◽  
...  
Keyword(s):  
Epithelial Mesenchymal Transition ◽  
Label Free ◽  
Raman Scattering Spectroscopy ◽  
Mesenchymal Transition ◽  
Alveolar Epithelial ◽  
Non Invasive ◽  
Process Characterization ◽  
Label Free Detection ◽  
Surface Enhanced Raman ◽  
Enhanced Raman Scattering

Here we present a sensitive, non-invasive, and label-free detection method for successful identification and discrimination of the BLM-induced EMT in ATII cells, which is based on the TAT-functionalized AuNSs as intracellular SERS probes.

scholarly journals Intracellular label-free detection of mesenchymal stem cell metabolism within a perivascular niche-on-a-chip

Lab on a Chip ◽  
2021 ◽  
Author(s):  
Simone Perottoni ◽  
Nuno G. B. Neto ◽  
Cesare Di Nitto ◽  
Ruslan I. Dmitriev ◽  
Manuela Teresa Raimondi ◽  
...  
Keyword(s):  
Stem Cell ◽  
Stem Cell Niche ◽  
Cell Metabolism ◽  
Perivascular Space ◽  
Label Free ◽  
Perivascular Niche ◽  
Non Invasive ◽  
Label Free Detection ◽  
Stem Cell Metabolism ◽  
Cell Niche

The stem cell niche at the perivascular space plays a role in dictating the fate of stem cells within it. This study predicts in silico and models the perivascular space, in a miniaturised bioreactor, with non-invasive assessment of cell metabolism.

scholarly journals Automated analysis of single cells using Laser Tweezers Raman Spectroscopy

The Analyst ◽  
2016 ◽  
Vol 141 (2) ◽  
pp. 689-696 ◽  
Author(s):  
S. Casabella ◽  
P. Scully ◽  
N. Goddard ◽  
P. Gardner
Keyword(s):  
Raman Spectroscopy ◽  
Cancer Cells ◽  
Single Cells ◽  
Automated Analysis ◽  
Laser Tweezers ◽  
Label Free ◽  
Significant Progress ◽  
Label Free Detection

In recent years, significant progress has been made into the label-free detection and discrimination of individual cancer cells using Laser Tweezers Raman Spectroscopy (LTRS).

Formulating SLN and NLC as Innovative Drug Delivery Systems for Non-Invasive Routes of Drug Administration

2020 ◽  
Vol 27 (22) ◽  
pp. 3623-3656 ◽  
Author(s):  
Bruno Fonseca-Santos ◽  
Patrícia Bento Silva ◽  
Roberta Balansin Rigon ◽  
Mariana Rillo Sato ◽  
Marlus Chorilli
Keyword(s):  
Drug Delivery ◽  
Particle Size ◽  
Drug Release ◽  
Drug Loading ◽  
Average Particle Size ◽  
Delivery Systems ◽  
Average Particle ◽  
Minor Importance ◽  
Routes Of Administration ◽  
Non Invasive

Colloidal carriers diverge depending on their composition, ability to incorporate drugs and applicability, but the common feature is the small average particle size. Among the carriers with the potential nanostructured drug delivery application there are SLN and NLC. These nanostructured systems consist of complex lipids and highly purified mixtures of glycerides having varying particle size. Also, these systems have shown physical stability, protection capacity of unstable drugs, release control ability, excellent tolerability, possibility of vectorization, and no reported production problems related to large-scale. Several production procedures can be applied to achieve high association efficiency between the bioactive and the carrier, depending on the physicochemical properties of both, as well as on the production procedure applied. The whole set of unique advantages such as enhanced drug loading capacity, prevention of drug expulsion, leads to more flexibility for modulation of drug release and makes Lipid-based nanocarriers (LNCs) versatile delivery system for various routes of administration. The route of administration has a significant impact on the therapeutic outcome of a drug. Thus, the non-invasive routes, which were of minor importance as parts of drug delivery in the past, have assumed added importance drugs, proteins, peptides and biopharmaceuticals drug delivery and these include nasal, buccal, vaginal and transdermal routes. The objective of this paper is to present the state of the art concerning the application of the lipid nanocarriers designated for non-invasive routes of administration. In this manner, this review presents an innovative technological platform to develop nanostructured delivery systems with great versatility of application in non-invasive routes of administration and targeting drug release.

scholarly journals The Role of Surface Chemistry in the Efficacy of Protein and DNA Microarrays for Label-Free Detection: An Overview

Polymers ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1026
Author(s):  
Elisa Chiodi ◽  
Allison M. Marn ◽  
Matthew T. Geib ◽  
M. Selim Ünlü
Keyword(s):  
Surface Chemistry ◽  
Surface Functionalization ◽  
Dna Microarrays ◽  
Label Free ◽  
Polymeric Coatings ◽  
Label Free Detection ◽  
Particle Imaging ◽  
Single Particle Imaging ◽  
The Impact

The importance of microarrays in diagnostics and medicine has drastically increased in the last few years. Nevertheless, the efficiency of a microarray-based assay intrinsically depends on the density and functionality of the biorecognition elements immobilized onto each sensor spot. Recently, researchers have put effort into developing new functionalization strategies and technologies which provide efficient immobilization and stability of any sort of molecule. Here, we present an overview of the most widely used methods of surface functionalization of microarray substrates, as well as the most recent advances in the field, and compare their performance in terms of optimal immobilization of the bioreceptor molecules. We focus on label-free microarrays and, in particular, we aim to describe the impact of surface chemistry on two types of microarray-based sensors: microarrays for single particle imaging and for label-free measurements of binding kinetics. Both protein and DNA microarrays are taken into consideration, and the effect of different polymeric coatings on the molecules’ functionalities is critically analyzed.

scholarly journals 3D phonon microscopy with sub-micron axial-resolution

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Richard J. Smith ◽  
Fernando Pérez-Cota ◽  
Leonel Marques ◽  
Matt Clark
Keyword(s):  
Signal To Noise Ratio ◽  
Single Cells ◽  
Optical Resolution ◽  
Acquisition Time ◽  
Label Free ◽  
Axial Resolution ◽  
Force Microscopy ◽  
Atomic Force ◽  
Accuracy And Precision ◽  
Good Agreement

AbstractBrillouin light scattering (BLS) is an emerging method for cell imaging and characterisation. It allows elasticity-related contrast, optical resolution and label-free operation. Phonon microscopy detects BLS from laser generated coherent phonon fields to offer an attractive route for imaging since, at GHz frequencies, the phonon wavelength is sub-optical. Using phonon fields to image single cells is challenging as the signal to noise ratio and acquisition time are often poor. However, recent advances in the instrumentation have enabled imaging of fixed and living cells. This work presents the first experimental characterisation of phonon-based axial resolution provided by the response to a sharp edge. The obtained axial resolution is up to 10 times higher than that of the optical system used to take the measurements. Validation of the results are obtained with various polymer objects, which are in good agreement with those obtained using atomic force microscopy. Edge localisation, and hence profilometry, of a phantom boundary is measured with accuracy and precision of approximately 60 nm and 100 nm respectively. Finally, 3D imaging of fixed cells in culture medium is demonstrated.

scholarly journals Label-Free Electrochemical Sensor for Rapid Bacterial Pathogen Detection Using Vancomycin-Modified Highly Branched Polymers

Sensors ◽  
2021 ◽  
Vol 21 (5) ◽  
pp. 1872
Author(s):  
Holger Schulze ◽  
Harry Wilson ◽  
Ines Cara ◽  
Steven Carter ◽  
Edward N. Dyson ◽  
...  
Keyword(s):  
Pathogen Detection ◽  
Electrochemical Impedance ◽  
Point Of Care ◽  
Branched Polymers ◽  
Label Free ◽  
Conformation Change ◽  
Gram Positive ◽  
Gram Positive Bacteria ◽  
Staphylococcus Carnosus ◽  
Label Free Detection

Rapid point of care tests for bacterial infection diagnosis are of great importance to reduce the misuse of antibiotics and burden of antimicrobial resistance. Here, we have successfully combined a new class of non-biological binder molecules with electrochemical impedance spectroscopy (EIS)-based sensor detection for direct, label-free detection of Gram-positive bacteria making use of the specific coil-to-globule conformation change of the vancomycin-modified highly branched polymers immobilized on the surface of gold screen-printed electrodes upon binding to Gram-positive bacteria. Staphylococcus carnosus was detected after just 20 min incubation of the sample solution with the polymer-functionalized electrodes. The polymer conformation change was quantified with two simple 1 min EIS tests before and after incubation with the sample. Tests revealed a concentration dependent signal change within an OD600 range of Staphylococcus carnosus from 0.002 to 0.1 and a clear discrimination between Gram-positive Staphylococcus carnosus and Gram-negative Escherichia coli bacteria. This exhibits a clear advancement in terms of simplified test complexity compared to existing bacteria detection tests. In addition, the polymer-functionalized electrodes showed good storage and operational stability.

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