Chikahiro Imashiro

Tissue engineering has attracted significant attention since the 1980s, and the applications of tissue engineering have been expanding. To produce a cell-dense tissue, cell sheet technology has been studied as a promising strategy. Fundamental techniques involving tissue engineering are mainly introduced in this review. First, the technologies to fabricate a cell sheet were reviewed. Although temperature-responsive polymer-based technique was a trigger to establish and spread cell sheet technolo

Hyperthermia has been studied as a noninvasive cancer treatment. Cancer cells show stronger thermal cytotoxicity than normal cells, which is exploited in hyperthermia. However, the absence of methods evaluating the thermal cytotoxicity in cells prevents the development of hyperthermia. To investigate the thermal cytotoxicity, culture temperature should be regulated. We, thus, developed a culture system regulating culture temperature immediately and accurately by employing metallic culture vessel

Proteinases that digest the extracellular matrix are usually used to harvest cells from culture vessels in a general culture process, which lowers the initial adhesion rate in regenerative medicine. Cell sheet engineering is one of the most important technologies in this field, especially for transplantation, because fabricated cell sheets have rich extracellular matrixes providing strong initial adhesion. Current cell sheet fabrication relies on temperature-responsive polymer-coated dishes. Cel

Collective cell migration plays a critical role in physiological and pathological processes such as development, wound healing, and metastasis. Numerous studies have demonstrated how various types of chemical, mechanical, and electrical cues dictate the collective migratory behaviors of cells. Although an acoustic cue can be advantageous because of its noninvasiveness and biocompatibility, cell migration in response to acoustic stimulation remains poorly understood. In this study, we developed a

Cell patterning methods have been previously reported for cell culture. However, these methods use inclusions or devices that are not used in general cell culture and that might affect cell functionality. Here, we report a cell patterning method that can be conducted on a general cell culture dish without any inclusions by employing a resonance vibration of a disk-shaped ultrasonic transducer located under the dish. A resonance vibration with a single nodal circle patterned C2C12 myoblasts into

Hyperthermia can be induced to exploit the thermal intolerance of cancer cells, which is worse than that of normal cells, as a potential noninvasive cancer treatment. To develop an effective hyperthermia treatment, thermal cytotoxicity of cells should be comprehensively investigated. However, to conduct such investigations, the culture temperature must be accurately regulated. We previously reported a culture system in which the culture temperature could be accurately regulated by employing meta

Spatial control of cell position is essential for numerous studies in tissue engineering, such as generation of linearly patterned muscle tissues, radially patterned liver lobule tissues, and circularly formed anal sphincter. This study proposes a novel method capable of patterning cells in a certain shape on a cell cultivation substrate. The concept is to pattern cells along the nodal position of resonance vibration on a cell cultivation substrate. Note that there are numerous resonance vibrati

The field of bioengineering depends on technologies for stable cell culture. Conventionally, every process involved in cell culture has been performed manually, so the culture efficiency and stability can vary between trials or depending on the technician. Among these processes, cell counting is particularly important because cell density affects cell function. Conventional cell counting techniques for cell number estimation are inefficient and unstable because they involve the manual work of co

The strength of cell adhesion is important in understanding the cell's health and in culturing them. Quantitative measurement of cell adhesion strength is a significant challenge in bioengineering research. For this, the present study describes a system that can measure cell adhesion strength using acoustic streaming induced by Lamb waves. Cells are cultured on an ultrasound transducer using a range of preculture and incubation times with phosphate-buffered saline (PBS) just before the measureme

Abstract This study describes multi-frequency Rayleigh wave excitation below 10 MHz, which is impossible with a conventional piezoelectric-single-crystal surface acoustic wave (SAW) device. To overcome this limitation, we utilized a SAW device with an elliptical reflector focusing structure (ELIPS). The prototype ELIPS SAW device excited a Rayleigh wave on a duralumin surface at 1.1 MHz, 3.4 MHz, 5.6 MHz, and 7.9 MHz in the single device. The maximum vibration velocities were 0.38 m s −1 , 0.21

In this paper, we propose a novel cell culture method to generate an organ without scaffold. The concept of our study is to apply the principle of Chladni's figures in cell manipulation. To confirm this concept, we developed cell cultivation device that can excite resonance vibration of the cell cultivation substrate. After the fabrication of the device, we estimated the resonance frequency and vibration amplitude distribution of our device. Since the fabricated device successfully produced the

Surgery, radiation therapy, and chemical therapy have been reported as the main treatments for cancer, which is one of the deadliest reported diseases. However, because of the high invasiveness of patients, cancer hyperthermia has been studied as a non-invasive treatment. Hyperthermia uses a difference in thermal tolerance between normal and cancer cells and provides an affected part thermal stimulation to kill cancer cells selectively. To develop effective conditions for hyperthermia, an in vit

Surgery, radiation therapy, and chemical therapy have been reported as main treatments for cancer that is one of the worst diseases reported. However, because of high invasiveness on patients, cancer hyperthermia has been studied as non-invasive treatment. Hyperthermia uses a difference of thermal tolerance between normal and cancer cells and gives an affected part thermal stimulation to kill cancer cells selectively. For developing effective conditions of hyperthermia, in vitro study to evaluat

Controlling cell orientation is of paramount importance in bioengineering processes. While several surface modification techniques have emerged to guide cell orientation, they often involve complex, repetitive procedures for each experiment. Thus, a streamlined approach for cell orientation is necessary. In this study, we present a potentially reusable metallic culture surface that induces an anisotropic cell orientation due to its unique geometric morphology. Using a femtosecond laser, periodic