Papers by Keyword: BioMEMS

Abstract: Paramecium bursaria is an unicellular organism that lives widely in fresh water environments such as rivers and ponds. Recent studies have suggested that in vivo cellular robotics using the cells of P. bursaria as micro-machines controllable under electrical and optical stimuli, has a variety of engineering applications such as transport of micro-sized particles in the capillary systems. The present study aimed to test if the swimming cells of P. bursaria, implementable in capillaries or on chips, are applicable for detection of metal ions. For model assays, rare earth elements (REEs) were chosen as target chemicals. In P. bursaria, LC₅₀ values for REE ions ranged between 2.0 and 62.7 µM. Among them, Sc was shown to be most toxic. In addition to the lethal impacts of REE ions, most of REE ions at sub-lethal concentrations at around 10 - 30 µM, showed inhibitory action against the motility of the cells during the electrically forced motility known as galvanotaxisis. In conclusion, in the non-lethal ranges of REE concentration, swimming cells of P. bursaria report the presence of REE ions, by lowering the motility.

Abstract: Members of Paramecium species are often referred to as “swimming neurons or sensory cells” applicable to micro-biorobotics or BioMEMS (biological micro-electro-mechanical systems). Paramecium bursaria known as green paramecia is an unicellular organism that lives widely in fresh water environments such as rivers and ponds. Recent studies have suggested that in vivo cellular robotics using the living cells of green paramecia as micro-machines controllable under electrical, optical and magnetic signals, has a variety of engineering applications such as transportation of micro-sized particles (ingested within the cells) in the capillary systems. In the present study, we aimed to test if the swimming environment of green paramecia can be implementable on microchips. For this purpose, the series of microchips were prepared for cellular swimming platform for green paramecia through fabrication of poly(methyl methacrylate) master plates using the programmable micro-milling system followed by polydimethylsiloxane-based micro-casting. Finally, microchips equipped with optimally sized micro-flow channels for allowing the single cell traffic by swimming green paramecia were successfully prepared, and thus further studies for application of green paramecium cells in BioMEMS are encouraged.

Abstract: The manipulation of emulsions at micrometer-scale is a challenging topic for industrial application, especially for monodisperse microemulsions production. The development of material science and afterwards the creation of polymer confinement proposed efficient devices for micrometer scale emulsions fabrication. In this work, the flow regime of emulsion generation was studied to depict numerical manipulation of micrometer-scale emulsions through biomicrofluidic technology. At first, correlation analysis between experiment conditions and results were conducted, then different linear modeling and non-linear modeling, including Artificial Neural Network Modeling (NNM) technology, were performed to characterize the emulsion variation. Both models can well manipulate emulsion variation. Compared with linear modeling, non-linear models ameliorate the performance on the manipulation of micrometer-scale emulsion.

Abstract: Surface stress-based biosensors as a crucial part of micro-scale and label-free system, use free energy change, the underlying concept in any binding reaction, have been investigated extensively in recent years. In this paper, a new bi-micro-cantilever surface stress biosensor is proposed which can be used to detect cells. Some fundamental study has been done, especially for the micro-cantilever due to its crucial role in the whole system. To acquiring the optimal material for more sensitive sensor, four material, Si, SiN, AlN, PMMA(polymethylmethacrylate), were contrastively analyzed under the same conditions (loads, size, environmental factor. etc) by finite element (FE) method. This study could provide some foundation for the biosensor design and fabrication.

Abstract: With new applications in the area of diagnostics, drug discovery and genetics, the need for Biological Micro-Electro-Mechanical Systems (BioMEMS) has increased tremendously in the last decade. Especially, surface stress-based BioMEMS has been investigated extensively in the recently years. In this paper, a new BioMEMS is proposed, which can be used to detect cells. It consists of microfluidics, square membrane and a fiber optic interferometer. The square membrane as the crucial and sensitive part includes three layers, self-assembled monolayer (SAM), gold and substrate material. Based on the BioMEMS, some fundamental study has been done, especially for the membrane due to its crucial role in the whole system. The finite element (FE) method has been used to study the membrane with different substrates. By the fundamental study, some important conclusions have been acquired: (1) The square membrane will reach maximal deflection at different ratio values (P: membrane size) to different substrates; (2) To a certain substrate, such as PDMS, the ratio making the membrane reach maximal deflection is different to dissimilar PDMS layer thickness; (3) If young’s modulus (E) of the substrate is too small, separation may happen between the gold layer and substrate layer when the gold size becomes smaller.