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Label-free interaction-triggered cell binding assay in autonomous microfluidic system with integrated flow-monitoring electrode system
Eszter Holczer, PhD student, HAS Centre for Energy Research
Current goal regarding the development of Point-of-Care (POC) medical devices is to design complex microfluidic systems capable of extracting biomedical information immediately. A polymer based, modular autonomous device was designed and fabricated with an integrated electrode system to fulfil this need and enable simple, robust detection of interactions between particulate elements of blood and the capillary wall.
The characteristics of blood flow was examined in specially designed microfluidic devices. These microfluidic systems have dedicated geometric structure and material composition to define suitable conditions for sensitive detection interactions between particulate elements of the blood and the adequately modified surfaces. As a model experiment the fast analysis of the AB0 blood group system was demonstrated, applying respective antibody reagents and capillary blood samples with different blood groups [1]. As an analytical signal the electrical resistance of parallel connected fluidic channels was detected to determine fluid movement and channel filling. The signal clearly refers to the change in blood flow rate, and quantifies the interactions between the functionalised channel walls and the specific cells.
Our proof-of-concept results point to a novel direction in blood analysis in autonomous microfluidic systems and also provide basis for construction simple quantitative device for blood screening for different diseases.
DETECTION OF BACTERIAL RNA USING ISOTACHOPHORESIS
Muhamed Adilovic, PhD student, International University of Sarajevo
Efficient treatment of bacterial infections requires quick, sensitive and specific detection of the pathogen. The setup presented in this work operates on the principles of isotachophoresis (ITP)[1] in a two-well microfluidic channel. Isolated 16s rRNA from cultured E. coli cells is placed together with fluorescent molecular probes in a well containing buffer. Hybridized targets constitute charged particles in the buffer, which move through the microchannel due to strong electric field applied between the wells. The channel has constant cross-sectional area. The probes are excited by 635nm light after passing 25mm through the channel, where the fluorescent signal is detected with a photomultiplier tube (PMT) connected to a microscope. Different ammounts of 16s rRNA (1, 0.5 and 0.1 microgram) are detected and compared with the detection of different concentrations of synthetic target oligonucleotides (10, 1 and 0.5 nM). Results suggest that the setup allows rapid and specific detection as well as quantification of bacteria present in the sample. Sensitivity and simplicity of the test indicate that this may be a valuable tool for clinical diagnostics that can find applications also outside detection of bacterial infections.
Biosensing using Nanofluidic Particle Size Sorting Device and Surface-Enhanced Raman Microscopy
Deepika Sharma, Doctoral Student, Paul Scherrer Institute
Micro/nanofluidic devices are extensively used for a plethora of applications in various fields such as diagnostics, material science, and biological studies by particle separation, sorting, trapping and immobilization. In recent years microfluidic devices have been main focus for improving diagnostic process by making the process more personalized, effective and automatic. For diagnostic and biological studies micro/nanofluidic devices are primarily used for selective separation, confinement and detection. Previously, we have demonstrated integrated passive static and tunable nanofluidic devices for size-based single nanoparticle trapping [1-3], which works on geometry-induced-electrostatic (GIE) trapping. To broaden the scope of our devices we achieved tunable functionalized nanofluidic devices, which allow trapping of positively [1] or negatively charged particles based on the surface charge polarity of the device surface [4]. Nevertheless, in GIE-trapping fluidic devices, particle trapping is influenced by salt concentration of the buffer solution. Thus, to achieve particle sorting and trapping independent of salt concentration we are developing integrating micro/nanofluidic device that allows nanoparticle separation, sorting and trapping. The device is further used for the detection of biomolecules using surface-enhanced Raman spectroscopy. This integrated micro/nanofluidic device can find potential applications as a biosensor for the multiplexed detection of biomolecules or analytes at extremely low concentrations.
Biosensing using Nanofluidic Particle Size Sorting Device and Surface-Enhanced Raman Microscopy
Deepika Sharma, Doctoral Student, Paul Scherrer Institute
Micro/nanofluidic devices are extensively used for a plethora of applications in various fields such as diagnostics, material science, and biological studies by particle separation, sorting, trapping and immobilization. In recent years microfluidic devices have been main focus for improving diagnostic process by making the process more personalized, effective and automatic. For diagnostic and biological studies micro/nanofluidic devices are primarily used for selective separation, confinement and detection. Previously, we have demonstrated integrated passive static and tunable nanofluidic devices for size-based single nanoparticle trapping [1-3], which works on geometry-induced-electrostatic (GIE) trapping. To broaden the scope of our devices we achieved tunable functionalized nanofluidic devices, which allow trapping of positively [1] or negatively charged particles based on the surface charge polarity of the device surface [4]. Nevertheless, in GIE-trapping fluidic devices, particle trapping is influenced by salt concentration of the buffer solution. Thus, to achieve particle sorting and trapping independent of salt concentration we are developing integrating micro/nanofluidic device that allows nanoparticle separation, sorting and trapping. The device is further used for the detection of biomolecules using surface-enhanced Raman spectroscopy. This integrated micro/nanofluidic device can find potential applications as a biosensor for the multiplexed detection of biomolecules or analytes at extremely low concentrations.
Removal and exclusion of micro-particle by magnetic artificial cilia
Shuaizhong Zhang, PhD candidate, Eindhoven University of Technology
The fouling of surfaces submerged in a liquid is an important problem for many applications. A specific example is the accumulation of micro-particles in Lab-on-a-chip devices, which for instance can block the microchannels, or interfere with sensing. One biologically inspired strategy to tackle this problem is given by cilia-induced particle transportation and cleaning. Biological cilia are micro-hairs or micro-pillars with a typical length between 2 and 15 micrometers, which are found ubiquitously in nature [1]. Cilia have been reported to have such functions as fluid propulsion, mechanical and chemical sensing, feeding, mucus removal from the human body, transport of microscopic particles, etc. Simulation works have verified that artificial cilia can be used to manipulate, such as capture, repel and propel, micro-particles in their vicinity [2]. Here, for the first time, we experimentally prove that magnetic artificial cilia are able to remove and exclude micro-particles from the ciliated area.
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