Yaxiaer Yalikun

Nara Institute of Science and Technology | NAIST · Graduate School of Materials Science

Contactless particle manipulation based on a thermal field has shown great potential for biological, medical, and materials science applications. However, thermal diffusion from a high-temperature area causes thermal damage to bio-samples. Besides, the permanent bonding of a sample chamber onto microheater substrates requires that the thermal field...

In this work, we investigated the ability of impedance flow cytometry to measure the shape of single cells/particles. We found that the impedance pulses triggered by micro-objects that are asymmetric in morphology show a tilting trend, and there is no such a tilting trend for symmetric ones. Therefore, we proposed a new metric, tilt index, to quant...

Intracellular components (including organelles and biomolecules) at the submicron level are typically analyzed in situ by special preparation or expensive setups. Here, a label-free and cost-effective approach of screening microalgal single-cells at a subcellular resolution is available based on impedance cytometry. To the best of our knowledge, it...

Here, we achieve shape-based separation of drug-treated Escherichia coli (E. coli) by viscoelastic microfluidics. Since shape is critical for modulating biological functions of E. coli, the ability to prepare homogeneous E. coli populations adopting uniform shape or sort bacterial sub-population based on their shape has significant implications for...

The electrical penetration of the cell membrane is vital for determining the cell interior via impedance cytometry. Herein, we propose a method for determining the conductivity of the cell membrane through the tilting levels of impedance pulses. When electrical penetration occurs, a high-frequency current freely passes through the cell membrane; th...

Bio-actuators and sensors are increasingly employed in microscale devices for numerous applications. Unlike other artificial devices actuated by living cells or tissues, here we introduce a microvalve system actuated by the stimuli-responsive action plant, Mimosa pudica (sleepy plant). This system realizes the control of the valve to open and close...

Single-cell analysis is essential to improve our understanding of cell functionality from cellular and subcellular aspects for diagnosis and therapy. Single-cell cultivation is one of the most important processes in single-cell analysis, which allows the monitoring of actual information of individual cells and provides sufficient single-cell clones...

Here we proposed a gas flow sensor enabled by 4 μm ultra-thin glass sheet with high-integration capability for applications in the fields of industry and medicine/health. The ultra-thin glass flow velocity sensor was fabricated with femtosecond laser processing in a time of several minutes, which can measure the gas flow velocity by detecting the d...

Dual-frequency impedance assays for intracellular components in microalgal cells Dual-frequency impedance assays enabled quantitative tracking of the changes in biophysical properties of E. gracilis cells at a high throughput (~900 cells/s). It is the fi rst time that the relationship between impedance signals and submicron intracellular organelles...

Techniques that can dexterously manipulate particles/cells are significant for biological detection, analytical chemistry, and material synthesis applications. Although there are many methods to realize the 3D manipulation in a static condition, there is a lack of sufficient 3D manipulating strategies in a continuous flow. We develop an integrated...

Cell staining is a typical procedure for assessing the distribution and density of intracellular components. In this work, a label-free alternative is developed and verified using impedance cytometry to characterize the loss of intracellular components in Euglena gracilis (E. gracilis) cells. By inhibiting chloroplast synthesis, the number of chlor...

Breast cancer is the most fatal disease among female cancers yet its detection still relies on needle biopsy. The unique physical and immune characteristics of breast cancer cells different from blood cells make them suitable to be employed as excellent biomarkers in liquid biopsy, through which breast cancer cells are collected from peripheral blo...

Transplantation of scaffold-embedded guided neurons has been reported to increase neuronal regeneration following brain injury. However, precise axonal integration between host and transplant neurons to form functional synapses remains a major problem. This study aims to develop a real-time femtosecond (fs) laser penetration on a 4 μm thick thin-gl...

Continuous microfluidic focusing of particles, both synthetic and biological, is significant for a wide range of applications in industry, biology and biomedicine. In this study, we demonstrate the focusing of particles in a microchannel embedded with glass grooves engraved by femtosecond pulse (fs) laser. Results showed that the laser-engraved mic...

We demonstrated a self-driven chemical micropump powered by self-oscillating motions of synthetic polymer gel converting chemical energy into displacements of a thin polydimethylsiloxane (PDMS) sheet to produce a directional flow via micro check valves. The gel oscillations induced by the oscillatory Belousov-Zhabotinsky (BZ) reaction generate larg...

Microfluidics has become recognized as a powerful platform technology with a wide range of applications in various fields, such as biology, biomedicine, chemistry and environment. To achieve higher performance, microfluidic devices are required to have superior optical transparency; mechanical, chemical and thermal stability; as well as easy design...

Glass is a common material used in various microsystems including sensors, actuators, and microfluidic devices due to its extraordinary properties. However, lack of flexibility and elasticity limits its potential for further applications. To solve this issue, thinning the thick glass plate to a few microns is a solution. However, conventional metho...

Cell rotation is one of the most important techniques for cell manipulation in modern bioscience, as it not only permits cell observation from any arbitrary angle, but also simplifies the procedures for analyzing the mechanical properties of cells, characterizing cell physiology, and performing microsurgery. Numerous approaches have been reported f...

Microfluidic focusing of particles (both synthetic and biological), which enables precise control over the positions of particles in a tightly focused stream, is a prerequisite step for the downstream processing, such as detection, trapping and separation. In this study, we propose a novel hydrodynamic focusing method by taking advantage of open v-...

Atomic force microscopy (AFM) can measure the mechanical properties of plant tissue at the cellular level, but for in situ observations, the sample must be held in place on a rigid support and it is difficult to obtain accurate data for living plants without inhibiting their growth. To investigate the dynamics of root cell stiffness during seedling...

Single-cell analysis is essential to deepen our understanding of cellular and subcellular cells at a single-cell level. Single-cell mechanism can be immediately observed during single-cell cultivation. Moreover, single-cell cultivation also provides sufficient cell numbers and product amounts for further single-cell manipulation and analysis. Micro...

Abstract Human iPS cell (iPSC)-derived cardiomyocytes (CMs) hold promise for drug discovery for heart diseases and cardiac toxicity tests. To utilize human iPSC-derived CMs, the establishment of three-dimensional (3D) heart tissues from iPSC-derived CMs and other heart cells, and a sensitive bioassay system to depict physiological heart function ar...

Cell mechanical properties, e.g. elastic and shear modulus, play vital roles in cell activities and functions, such as cell growth, cell division, cell motion, and cell adhesion. Measurement of single-cell mechanical properties has attracted great interest from both academia and industry, due to its importance in a variety of applications, such as...

A flexible manipulation platform was constructed combining microheaters and an area cooling temperature system to produce enough force to steer sedimentary particles or cells and to limit the thermal diffusion. The platform has a fixed motherboard with microheaters and an exchangeable sample chamber that provides disposable use. It enables steering...

This paper presents a self-contained micro-optical system that is magnification-controlled by adjusting the positions of the microlens in the device via pneumatic air pressure. Unlike conventional dynamic microlenses made from a liquid or polydimethylsiloxane (PDMS) that change their shapes via external actuation, this system combines a fixed-curva...

In a conventional glass microfluidic system, the vertical connection is the most frequently used for connections between a microfluidic device and its peripheral equipment. However, it leads to a significant pressure drop at the inlet of a microfluidic device, decreases the flow velocity, and can introduce few samples than expected. To overcome the...

We present an efficient fabrication technique for a glass microdome structure (GMDS) based on the microthermal expansion principle, by inflating the microcavities confined between two thin glass slides. This technique allows controlling the height, diameter, and shape of the GMDS with a uniformity under 5%. The GMDS has a high potential for the app...

Efficient and reliable manipulation of biological particles is crucial in medical diagnosis and chemical synthesis. Inertial microfluidic devices utilizing passive hydrodynamic forces in the secondary flow have drawn considerable attention for their high throughputs, low costs, and harmless particle manipulation. However, as the dominant mechanism,...

Imaging flow cytometry is a powerful tool by virtue of its capability for high-throughput cell analysis. The advent of high-speed optical imaging methods on a microfluidic platform has significantly improved cell throughput and brought many degrees of freedom to instrumentation and applications over the last decade, but it also poses a predicament...

We report an on-chip single-cell multidirectional observation method by accurately control the ultra-thin glass chamber rotation angles over the microscope. This technique enables to establish the multidirectional visual accesses to the target cell that captured inside of the thin glass chamber. The ultra-thin glass chamber has advantages of hig...

Sub-micrometer particles (0.10 – 1.0 μm) are of great significance to study, e.g., microvesicles and protein aggregates are targets for therapeutic intervention, and sub-micrometer fluorescent polystyrene (PS) particles are used as probes for diagnostic imaging. Focusing of sub-micrometer particles – precisely control over the position of sub-micro...

Drug susceptibility (also called chemosensitivity) is an important criterion for developing a therapeutic strategy for various cancer types such as breast cancer and leukemia. Recently, functional assays such as high-content screening together with genomic analysis have been shown to be effective for predicting drug susceptibility, but their clinic...

We report a high-speed manipulation method to control flow direction of micro-particles in microfluidic chip activated by a femtosecond (fs) laser impulse. When the femtosecond laser pulse is focused in the channel, a micro-explosion is induced and generates an impulsive force at the laser focal point. In this method, the impulsive force initiated...

Combining the strength of flow cytometry with fluorescence imaging and digital image analysis, imaging flow cytometry is a powerful tool in diverse fields including cancer biology, immunol-ogy, drug discovery, microbiology, and metabolic engineering. It enables measurements and statistical analyses of chemical, structural , and morphological phenot...

Development of bio-microactuators combining microdevices and cellular mechanical functions has been an active research field owing to their desirable properties including high mechanical integrity and biocompatibility. Although various types of devices were reported, the use of as-is natural muscle tissue should be more effective. An earthworm musc...

Time-course analysis of single cells is important to characterize heterogeneous activities of individual cells such as the metabolic response to their environment. Single-cell isolation is an essential step prior to time-course analysis of individual cells by collecting, culturing, and identifying multiple single-cell targets. Although single-cell...

Recent progress in microengineering has included the demonstration of various micropumps; however, these pumps are typically driven by an external energy source such as an electrical power source. Thus, there is a limitation to the integration of such pumps into microdevices. Here, we report fabrication of the world smallest autonomous hybrid pump...

Bio-actuators that use insect muscular tissue have attracted attention from researchers worldwide because of their small size, self-motive property, self-repairer ability, robustness, and the need for less environment management than mammalian cells. To demonstrate the potential of insect muscular tissue for use as bio-actuators, three types of the...

The manipulation of micro/nanoparticles has becomeincreasingly important in biological and industrial fields.As a non-contact method for particle manipulation, acousticfocusing has been applied in sorting, enrichment andanalysis of particles with microfluidic devices. Althoughthe frequency and amplitude of acoustic waves and thedimensions of microc...

Single cell analysis has gained attention as a means to investigate the heterogeneity of cells and amplify a cell with desired characteristics. However, obtaining a single cell from a large number of cells remains difficult because preparation of single-cell samples relies on conventional techniques such as pipetting that are labor intensive. In th...

Effective and high-throughput cell sorting are critical technologies in single cell analysis in biology, medicine and clinical applications. Especially for single cell analysis requiring high accuracy, multiple sorting mechanisms are required, and they need to be well organized into a system based on the sorting ability. Therefore, we classify most...

4-step micro glass blowing method for all glass lens array fabrication.

Earthworm muscle-tissue actuated atmospheric-operable 3D printed wheel runner

Earthworm muscle driven valve with both electrical and chemical controls

Development of a bioassay system to evaluate the pulsatile function of human heart tissue using a cellular micropump on-chip and a biomimetic human iPS cell-derived heart tissue sheet technology

Thin glass microfluidic system for observation of isolated single Euglena gracilis

Atmospheric-operable 3D printed walking bio-robot powered by muscle-tissue of earthworm

Slide-in horizontal microfluidic connection method for high pressure/high speed on-chip application

Enhanced acoustic focusing of nano/microparticles in thin glass microfluidic devices

Single-cell capture plays an important role in single-cell manipulation and analysis. This paper presents a microfluidic device for deterministic single-cell trapping based on the hydrodynamic trapping mechanism. The device is composed of an S-shaped loop channel and thousands of aligned trap units. This arrayed structure enables each row of the de...

This paper investigates the basic deflection properties of polydimethylsiloxane (PDMS) membrane as an actuator component in a microfluidic device. Polydimethylsiloxane membrane is a widely used structure in various applications in microfluidics. Most of the applications using PDMS membrane as actuators are pumps, valves, microlenses, and cell stimu...

In the fields of cell biology, such as biomolecular chemistry and genomics, microbeads play an important role as a powerful analysis tool. To realize above applications, manipulation of size selection of microbeads is required. Therefore, in this paper we summarized newest manipulation methods for size selection of microbeads and their applications...

A fundamental challenge of biology is to understand the vast heterogeneity of cells, particularly how cellular composition, structure, and morphology are linked to cellular physiology. Unfortunately, conventional technologies are limited in uncovering these relations. We present a machine-intelligence technology based on a radically different archi...