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Enhanced immunoassay in a nanofluidic preconcentrator utilizing nano-interstices among self-assembled gold nanoparticles. Biomed Microdevices 2022; 24:19. [DOI: 10.1007/s10544-022-00619-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/20/2022] [Indexed: 11/02/2022]
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Monkman GJ, Sindersberger D, Prem N, Diermeier A, Szecsey T. Dielectric behaviour of magnetic hybrid materials. PHYSICAL SCIENCES REVIEWS 2020. [DOI: 10.1515/psr-2019-0121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Abstract
The objectives of this work include the analysis of electrical and magnetic properties of magneto-elastic hybrid materials with the intention of developing new techniques for sensor and actuator applications. This includes the investigation of dielectric properties at both low and high frequencies. The behaviour of capacitors whose dielectrics comprise magnetic hybrid materials is well known. Such interfacial magnetocapacitance can be varied according to magnetic content, magnetic flux density and the relative permittivity of the polymer matrix together with other dielectric content. The basic function of trapping electrical charges in polymers (electrets) is also established technology. However, the combination of magnetoactive polymers and electrets has led to the first electromagnetic device capable of adhering to almost any material, whether magnetically susceptible or not. During the course of this research, in addition to dielectrics, electrically conductive polymers based on (PDMS) matrices were developed in order to vary the electrical properties of the material in a targeted manner. In order to ensure repeatable results, this demanded new fabrication techniques hitherto unavailable. The 3D printing of silicones is far from being a mature technology and much pioneering work was necessary before extending the usual 3 d.o.f. to include orientation about and diffusion of particles in these three axes, thus leading to the concept of 6D printing. In 6D printing, the application of a magnetic field can be used during the curing process to control the particulate distribution and thus the spatial filler particle density as desired. Most of the devices (sensors and actuators) produced by such methods contain levels of carbonyl iron powder (CIP) embedded magnetic filler of up to 70 wt%. Contrary to this, a hitherto neglected research area, namely magnetoactive polymers (MAPs) having significantly lower magnetic particle concentrations (1 to 3 wt% CIP) were also investigated. With filler concentrations lower than 3 wt%, structures are formed which are completely absent at higher filler levels. CIP concentrations in the range of 1wt% demonstrate the formation of toroidal structures. Further development of coherent rings with a compact order results as filler concentrations increase towards 2 wt%. Above 3 wt% the structure eventually disintegrates to the usual random order found in traditional MAP with higher CIP content. Structured samples containing 1%–3 wt% CIP were investigated with the aid of X-ray tomography where solitary ring structures can be observed and eventually the formation of capillary doubles. Over wavelengths ranging from 1 to 25 µm, spectroscopic analysis of thin film MAP samples containing 2 wt% CIP revealed measurable magnetic-field-dependent changes in IR absorption at a wavenumber 2350 (λ = 4.255 µm). This was found to be due to the diamagnetic susceptibility of atmospheric carbon dioxide (CO2). Consequently, the first potential application for sparse matrix MAPs was found.
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Affiliation(s)
| | | | - Nina Prem
- Mechatronics Research Unit , OTH-Regensburg , Regensburg , Germany
| | | | - Tamara Szecsey
- Mechatronics Research Unit , OTH-Regensburg , Regensburg , Germany
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Choi J, Baek S, Kim HC, Chae JH, Koh Y, Seo SW, Lee H, Kim SJ. Nanoelectrokinetic Selective Preconcentration Based on Ion Concentration Polarization. BIOCHIP JOURNAL 2020. [DOI: 10.1007/s13206-020-4109-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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Prem N, Sindersberger D, Monkman GJ. Infrared spectral analysis of low concentration magnetoactive polymers. J Appl Polym Sci 2020. [DOI: 10.1002/app.48366] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Nina Prem
- Mechatronics Research Unit, OTH‐Regensburg Germany
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Suhito IR, Kang ES, Kim DS, Baek S, Park SJ, Moon SH, Luo Z, Lee D, Min J, Kim TH. High density gold nanostructure composites for precise electrochemical detection of human embryonic stem cells in cell mixture. Colloids Surf B Biointerfaces 2019; 180:384-392. [PMID: 31082776 DOI: 10.1016/j.colsurfb.2019.04.059] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Revised: 04/18/2019] [Accepted: 04/29/2019] [Indexed: 01/10/2023]
Abstract
Precise detection of undifferentiated human pluripotent stem cells (hPSCs) and their entire subsequent elimination are incredibly important in preventing teratoma formations after transplantation. Recently, electrochemical sensing platforms have demonstrated immense potential as a new tool to detect remaining hPSCs in label-free and non-destructive manner. Nevertheless, one of the critical huddles of this electrochemical sensing approach is its low sensitivity since even low concentrations of remaining hPSCs were reported to form teratoma once transplanted. To address this issue, in this study, we report an engineering-based approach to improve the sensitivity of electrochemical sensing platform for hPSC detection. By optimizing the density of gold nanostructure and the matrigel concentration to improve both electro-catalytic property and biocompatibility, the sensitivity of the developed platform toward hESCs detection could reach 12,500 cells/chip, which is close to the known critical concentration of hPSCs (˜10,000 cells) that induce teratoma formation in vivo. Remarkably, the electrochemical signals were not detectable from other types of stem cell-derived endothelial cells (CB-EPCs) even at high concentrations of CB-EPCs (40,000 cells/chip), proving the high selectivity of the developed platform toward hPSC detection. Hence, the developed platform could be highly useful to solve the safety issues that are related with clinical application of hPSC-derived cells.
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Affiliation(s)
- Intan Rosalina Suhito
- School of Integrative Engineering, Chung-Ang University, Seoul 06974, Republic of Korea
| | - Ee-Seul Kang
- School of Integrative Engineering, Chung-Ang University, Seoul 06974, Republic of Korea
| | - Da-Seul Kim
- School of Integrative Engineering, Chung-Ang University, Seoul 06974, Republic of Korea
| | - Seungho Baek
- School of Integrative Engineering, Chung-Ang University, Seoul 06974, Republic of Korea
| | - Soon-Jung Park
- Department of Medicine, School of Medicine, Konkuk University, Seoul 05029, Republic of Korea
| | - Sung-Hwan Moon
- Department of Stem Cell Biology, School of Medicine, Konkuk University, Seoul 05029, Republic of Korea
| | - Zhengtang Luo
- Department of Chemical and Biological Engineering, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon 999077, Hong Kong, China
| | - Donghyun Lee
- School of Integrative Engineering, Chung-Ang University, Seoul 06974, Republic of Korea
| | - Junhong Min
- School of Integrative Engineering, Chung-Ang University, Seoul 06974, Republic of Korea.
| | - Tae-Hyung Kim
- School of Integrative Engineering, Chung-Ang University, Seoul 06974, Republic of Korea; Integrative Research Center for Two-Dimensional Functional Materials, Institute of Interdisciplinary Convergence Research, Chung-Ang University, Seoul 06974, Republic of Korea.
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Selective Detection of Human Lung Adenocarcinoma Cells Based on the Aptamer-Conjugated Self-Assembled Monolayer of Gold Nanoparticles. MICROMACHINES 2019; 10:mi10030195. [PMID: 30893795 PMCID: PMC6470481 DOI: 10.3390/mi10030195] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Revised: 03/09/2019] [Accepted: 03/17/2019] [Indexed: 12/24/2022]
Abstract
This study established a microfluidic chip for the capture of A549 human lung circulating tumor cells via the aptamer-conjugated self-assembled monolayer (SAM) of gold nanoparticles (AuNPs) in the channel. AuNPs are among the most attractive nanomaterials for the signal enhancement of biosensors owing to their unique chemical, physical, and mechanical properties. The microchip was fabricated using soft photolithography and casting and molding techniques. A self-assembly method was designed to attach AuNPs, cell-specific aptamers, and target cells onto the desired area (i.e., SAM area). In this study, the gold microelectrode configuration was characterized by fluorescence microscopy and impedance measurements to confirm the important modification steps. Subsequently, several investigations with the proposed assay were conducted with different cell samples to determine the specific binding ability of the device for A549 adenocarcinoma cancer cells. This work has ensured a simple, convenient, selective, and sensitive approach for the development of biosensors for lung cancer detection during the early stages.
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