High-Throughput 3D MicroPhysiological Systems

Shuichi TAKAYAMA 한국생물공학회 2022 한국생물공학회 학술대회 Vol.2022 No.9

Microscale Determination of Aqueous Two Phase System Binodals by Droplet Dehydration in Oil

Kojima, Taisuke,Takayama, Shuichi American Chemical Society 2013 ANALYTICAL CHEMISTRY - Vol.85 No.10

<P>This paper analyzes the use of a dehydrating oil system to determine binodal curves of an aqueous two phase system (ATPS). Aqueous droplets containing phase-forming polymers are dehydrated at the interface between two immiscible oils. The droplets shrink due to diffusion of water into the oil phase while constantly maintaining a spherical shape. Upon sufficient dehydration, dilute one-phase solutions of phase-forming polymers separate into two phases. Comparison of the droplet diameter at this phase separation point and at the beginning allows facile calculation of the concentration of polymers that determine the binodal curve. The miniaturized droplet dehydration-based binodals obtained in this manner matched the binodals determined by the conventional diluting method but using several orders of magnitude less sample volume (150 nL droplets versus 10 mL vials).</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/ancham/2013/ancham.2013.85.issue-10/ac400628b/production/images/medium/ac-2013-00628b_0009.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/ac400628b'>ACS Electronic Supporting Info</A></P>

Organ-on-a-chip and the kidney

( Se Joong Kim ),( Shuichi Takayama ) 대한신장학회 2015 Kidney Research and Clinical Practice Vol.34 No.3

Traditional approaches to pathophysiology are advancing but still have many limitations that arise from real biologic systems and their associated physiological phenomena being too complicated. Microfluidics is a novel technology in the field of engineering, which provides new options that may overcome these hurdles. Microfluidics handles small volumes of fluids and may apply to various applications such as DNA analysis chips, other lab-on-a-chip analyses, micropropulsion, and microthermal technologies. Among them, organ-on-a-chip applications allow the fabrication of minimal functional units of a single organ or multiple organs. Relevant to the field of nephrology, renal tubular cells have been integrated with microfluidic devices for making kidneys-on-a-chip. Although still early in development, kidneys-on-a-chip are showing potential to provide a better understanding of the kidney to replace some traditional animal and human studies, particularly as more cell types are incorporated toward the development of a complete glomerulion- a-chip.

Receptor differential activation and cooperativity better explain cellular preference for different chemoattractant gradient shapes in an EGFR system

White, Joshua B.,Takayama, Shuichi Royal Society of Chemistry 2011 Integrative biology Vol.3 No.10

<P>This manuscript describes mathematical models that apply an aggregating receptor scheme to the epidermal growth factor receptor (EGFR) system to interpret and predict directed cell migration behaviors in differently-shaped chemoattractant gradients. This method incorporates the latest biochemical insights on ligand–receptor activation kinetics and receptor cooperativity into the commonly used difference in the fractional receptor occupancy (DFRO) model for explaining chemotaxis. The enhanced model derives the functionally more relevant value of difference in fractional receptor activation (DFRA). This DFRA analysis encompasses all features and predictions of the DFRO analyses. Importantly, DFRA analysis can additionally explain <I>in vitro</I> microfluidic chemotaxis experiments that are difficult to explain using only DFRO concepts such as why some cells may migrate well only in a higher concentration regime of exponential chemoattractant gradients. The DFRA analysis also suggests receptor activation strategies that cells may use to tune their responsiveness to differently-shaped <I>in vivo</I> gradients. DFRA analysis is conceptually and computationally straightforward. The results it provides are envisioned to serve as quick semi-quantitative guides to design chemotaxis experiments and to develop hypotheses for interpretation of results from directed cell migration experiments.</P> <P>Graphic Abstract</P><P>Mathematical models incorporating equilibrium binding kinetics, receptor activation, and receptor cooperativity are used as a predictive metric of cell chemotaxis in microfluidic gradient generators. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c1ib00040c'> </P>

Regulating microenvironmental stimuli for stem cells and cancer cells using microsystems

Park, Joong Yull,Takayama, Shuichi,Lee, Sang-Hoon Royal Society of Chemistry 2010 Integrative biology Vol.2 No.5

<P>Cells express hundreds of different types of receptors, which they use to continuously monitor their chemical and mechanical microenvironments. Stem cells and cancer cells are particularly sensitive to microenvironmental cues because their interactions have profound effects on stem cell potency and tumorigenesis, respectively. Unlike conventional tissue culture in wells and dishes, microtechnology with dimensions on the cellular scale can be combined with materials, chemicals, physiological flows, and other effectors to provide high levels of control in a format more flexible than macroscale <I>in vitro</I> or <I>in vivo</I> systems, revealing stimulation-specific responses of stem cells and cancer cells. Microtechnology-integrated biology enable the simultaneous control of multiple numbers of biological microenvironmental factors in a high-throughput manner. In this review we present representative examples of the use of microtechnology systems to regulate the mechanical, chemical, topological, adhesive, and other environments of individual stem cells and cancer cells. We then explore the possibilities for simultaneous multimodal control of combinations of these environmental factors.</P> <P>Graphic Abstract</P><P>Microtechnology in regulating single or multiple biological stimuli will offer great opportunities to reveal new cellular behaviors for stem cell and cancer research. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c000442a'> </P>

Mini Review : The art of reporter proteins in science: past, present and future applications

( Cheol Min Ghim ),( Sung Kuk Lee ),( Shuichi Takayama ),( Robert J. Mitchell ) 생화학분자생물학회 (구 한국생화학분자생물학회) 2010 BMB Reports Vol.43 No.7

Starting with the first publication of lacZ gene fusion in 1980, reporter genes have just entered their fourth decade. Initial studies relied on the simple fusion of a promoter or gene with a particular reporter gene of interest. Such constructs were then used to determine the promoter activity under specific conditions or within a given cell or organ. Although this protocol was, and still is, very effective, current research shows a paradigm shift has occurred in the use of reporter systems. With the advent of innovative cloning and synthetic biology techniques and microfluidic/nanodroplet systems, reporter genes and their proteins are now finding themselves used in increasingly intricate and novel applications. For example, researchers have used fluorescent proteins to study biofilm formation and discovered that microchannels develop within the biofilm. Furthermore, there has recently been a “fusion” of art and science; through the construction of genetic circuits and regulatory systems, researchers are using bacteria to “paint” pictures based upon external stimuli. As such, this review will discuss the past and current trends in reporter gene applications as well as some exciting potential applications and models that are being developed based upon these remarkable proteins. [BMB reports 2010; 43(7): 451-460]

Studying Adipose Tissue in the Breast Tumor Microenvironment In Vitro: Progress and Opportunities

Mertz David,Sentosa Jason,Luker Gary,Takayama Shuichi 한국조직공학과 재생의학회 2020 조직공학과 재생의학 Vol.17 No.6

Background: The breast cancer microenvironment contains a variety of stromal cells that are widely implicated in worse patient outcomes. While many in vitro models of the breast tumor microenvironment have been published, only a small fraction of these feature adipocytes. Adipocytes are a cell type increasingly recognized to have complex functions in breast cancer. Methods: In this review, we examine findings from recent examples of in vitro experiments modeling adipocytes within the local breast tumor microenvironment. Results: Both two-dimensional and three-dimensional models of adipocytes in the breast tumor microenvironment are covered in this review and both have uncovered interesting phenomena related to breast tumor progression. Conclusion: Certain aspects of breast cancer and associated adipocyte biology: extracellular matrix effects, cell-cell contact, and physiological mass transport can only be examined with a three-dimensional culture platform. Opportunities remain for innovative improvements to be made to in vitro models that further increase what is known about adipocytes during breast cancer progression.

Preprogrammed, Parallel On-Chip Immunoassay Using System-Level Capillarity Control

Kim, Sung-Jin,Paczesny, Sophie,Takayama, Shuichi,Kurabayashi, Katsuo American Chemical Society 2013 ANALYTICAL CHEMISTRY - Vol.85 No.14

<P>Fully manual use of conventional multiwell plates makes enzyme-linked immunosorbent assay (ELISA)-based immunoassays highly time-consuming and labor-intensive. Here, we present a capillarity-driven on-chip immunoassay that greatly saves time and labor with an inexpensive setup. Our immunoassay process starts with pipetting multiple solutions into multiwells constructed on a microfluidic device chip. Subsequently, capillarity spontaneously transports multiple sample solutions and common reagent solutions into assigned detection channels on the chip in a purely passive and preprogrammed manner. Our device implements capillarity-driven immunoassays involving four sample and six reagent solutions within 30 min by orchestrating the functions of on-chip passive components. Notably, our immunoassay technique reduces the total number of pipetting processes by ∼5 times, as compared to assays on multiwell plates (48 vs 10). This assay technique allows us to quantify the concentrations of C-reactive protein and suppressor of tumorigenicity 2 with a detection limit of 8 and 90 pM, respectively. This device should be useful for sophisticated, parallel biochemical microfluidic processing in point-of-care settings under limited resources.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/ancham/2013/ancham.2013.85.issue-14/ac401292d/production/images/medium/ac-2013-01292d_0005.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/ac401292d'>ACS Electronic Supporting Info</A></P>

Lab-on-a-chip biophotonics: its application to assisted reproductive technologies

Lai, David,Smith, Gary D.,Takayama, Shuichi Wiley (John WileySons) 2012 Journal of biophotonics Vol.5 No.8

<P>With the benefits of automation, sensitivity and precision, microfluidics has enabled complex and otherwise tedious experiments. Lately, lab-on-a-chip (LOC) has proven to be a useful tool for enhancing non-invasive assisted reproductive technology (ART). Non-invasive gamete and embryo assessment has largely been through periodic morpohological assessment using optical microscopy and early LOC ART was the same. As we realize that morphological assessment is a poor indication of gamete or embryo health, more advanced biophotonics has emerged in LOC ART to assay for metabolites or gamete separation via optoelectrical tweezers. Off-chip, even more advanced biophotonics with broad spectrum analysis of metabolites and secretomes has been developed that show even higher accuracy to predicting reproductive potential. The integration of broad spectrum metabolite analysis into LOC ART is an exciting future that merges automation and sensitivity with the already highly accurate and strong predictive power of biophotonics.</P>

Room Temperature Phosphorescence of Metal-Free Organic Materials in Amorphous Polymer Matrices

Lee, Dongwook,Bolton, Onas,Kim, Byoung Choul,Youk, Ji Ho,Takayama, Shuichi,Kim, Jinsang American Chemical Society 2013 JOURNAL OF THE AMERICAN CHEMICAL SOCIETY - Vol.135 No.16

<P>Developing metal-free organic phosphorescent materials is promising but challenging because achieving emissive triplet relaxation that outcompetes the vibrational loss of triplets, a key process to achieving phosphorescence, is difficult without heavy metal atoms. While recent studies reveal that bright room temperature phosphorescence can be realized in purely organic crystalline materials through directed halogen bonding, these organic phosphors still have limitations to practical applications due to the stringent requirement of high quality crystal formation. Here we report bright room temperature phosphorescence by embedding a purely organic phosphor into an amorphous glassy polymer matrix. Our study implies that the reduced beta (β)-relaxation of isotactic PMMA most efficiently suppresses vibrational triplet decay and allows the embedded organic phosphors to achieve a bright 7.5% phosphorescence quantum yield. We also demonstrate a microfluidic device integrated with a novel temperature sensor based on the metal-free purely organic phosphors in the temperature-sensitive polymer matrix. This unique system has many advantages: (i) simple device structures without feeding additional temperature sensing agents, (ii) bright phosphorescence emission, (iii) a reversible thermal response, and (iv) tunable temperature sensing ranges by using different polymers.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/jacsat/2013/jacsat.2013.135.issue-16/ja401769g/production/images/medium/ja-2013-01769g_0008.gif'></P>