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1.
Adv Healthc Mater ; : e2303477, 2024 May 20.
Article in English | MEDLINE | ID: mdl-38768494

ABSTRACT

Here an electrical stimulation system is described for maturing microfiber-shaped cardiac tissue (cardiac microfibers, CMFs). The system enables stable culturing of CMFs with electrical stimulation by placing the tissue between electrodes. The electrical stimulation device provides an electric field covering whole CMFs within the stimulation area and can control the beating of the cardiac microfibers. In addition, CMFs under electrical stimulation with different frequencies are examined to evaluate the maturation levels by their sarcomere lengths, electrophysiological characteristics, and gene expression. Sarcomere elongation (14% increase compared to control) is observed at day 10, and a significant upregulation of electrodynamic properties such as gap junction protein alpha 1 (GJA1) and potassium inwardly rectifying channel subfamily J member 2 (KCNJ2) (maximum fourfold increase compared to control) is observed at day 30. These results suggest that electrically stimulated cultures can accelerate the maturation of microfiber-shaped cardiac tissues compared to those without electrical stimulation. This model will contribute to the pathological research of unexplained cardiac diseases and pharmacologic testing by stably constructing matured CMFs.

2.
Adv Sci (Weinh) ; 10(35): e2301831, 2023 Dec.
Article in English | MEDLINE | ID: mdl-37849230

ABSTRACT

In vitro reconstruction of highly mature engineered heart tissues (EHTs) is attempted for the selection of cardiotoxic drugs suitable for individual patients before administration. Mechanical contractile force generated in the EHTs is known to be a critical indicator for evaluating the EHT response. However, measuring contractile force requires anchoring the EHT in a tailored force-sensing cell culture chamber, causing technical difficulties in the stable evaluation of contractile force in long-term culture. This paper proposes a hydrogel-sheathed human induced pluripotent stem cell (hiPSC)-derived heart microtissue (H3 M) that can provide an anchor-free contractile force measurement platform in commonly used multi-well plates. The contractile force associated with tissue formation and drug response is calculated by motion tracking and finite element analysis on the bending angle of the hydrogel sheath. From the experiment of the drug response, H3 M is an excellent drug screening platform with high sensitivity and early testing capability compared to conventionally anchored EHT. This unique platform would be useful and versatile for regenerative therapy and drug discovery research in EHT.


Subject(s)
Induced Pluripotent Stem Cells , Humans , Myocytes, Cardiac , Hydrogels , Mechanical Phenomena , Muscle Contraction
3.
ACS Nano ; 17(15): 14981-14989, 2023 Aug 08.
Article in English | MEDLINE | ID: mdl-37458690

ABSTRACT

N,N-Dimethylformamide (DMF) is an essential solvent in industries and pharmaceutics. Its market size range was estimated to be 2 billion U.S. dollars in 2022. Monitoring DMF in solution environments in real time is significant because of its toxicity. However, DMF is not a redox-active molecule; therefore, selective monitoring of DMF in solutions, especially in polar aqueous solutions, in real time is extremely difficult. In this paper, we propose a selective DMF sensor using a molybdenum disulfide (MoS2) field-effect transistor (FET). The sensor responds to DMF molecules but not to similar molecules of formamide, N,N-diethylformamide, and N,N-dimethylacetamide. The plausible atomic mechanism is the oxygen substitution sites on MoS2, on which the DMF molecule shows an exceptional orientation. The thin structure of MoS2-FET can be incorporated into a microfluidic chamber, which leads to DMF monitoring in real time by exchanging solutions subsequently. The designed device shows DMF monitoring in NaCl ionic solutions from 1 to 200 µL/mL. This work proposes the concept of selectively monitoring redox-inactive molecules based on the nonideal atomic affinity site on the surface of two-dimensional semiconductors.

4.
Sci Rep ; 13(1): 11932, 2023 07 24.
Article in English | MEDLINE | ID: mdl-37488180

ABSTRACT

Chitosan has various tissue regeneration effects. This study was designed to investigate the nerve regeneration effect of Schwann cell (SC)-encapsulated chitosan-collagen hydrogel nerve conduit (CCN) transplanted into a rat model of sciatic nerve defect. We prepared a CCN consisting of an outer layer of chitosan hydrogel and an inner layer of collagen hydrogel to encapsulate the intended cells. Rats with a 10-mm sciatic nerve defect were treated with SCs encapsulated in CCN (CCN+), CCN without SCs (CCN-), SC-encapsulated silicone tube (silicone+), and autologous nerve transplanting (auto). Behavioral and histological analyses indicated that motor functional recovery, axonal regrowth, and myelination of the CCN+ group were superior to those of the CCN- and silicone+ groups. Meanwhile, the CCN- and silicone+ groups showed no significant differences in the recovery of motor function and nerve histological restoration. In conclusion, SC-encapsulated CCN has a synergistic effect on peripheral nerve regeneration, especially axonal regrowth and remyelination of host SCs. In the early phase after transplantation, SC-encapsulated CCNs have a positive effect on recovery. Therefore, using SC-encapsulated CCNs may be a promising approach for massive peripheral nerve defects.


Subject(s)
Chitosan , Rats , Animals , Rodentia , Hydrogels , Sciatic Nerve , Schwann Cells , Collagen , Nerve Regeneration , Silicones
5.
Adv Healthc Mater ; 11(1): e2101509, 2022 01.
Article in English | MEDLINE | ID: mdl-34694694

ABSTRACT

Since the biochemical reaction of blood vessels plays an essential role in immune response or various diseases, in vitro vascular models have high demand from medical fields. However, vascular models often tend to be difficult to mimic the biomedical reaction faithfully because of the lack of implementation of the tissue deformation. Here, an inflammatory mediator-induced deformation reaction of a blood vessel on a flexibly deformable collagen hydrogel tube device is reproduced. A self-standing collagen tube enables the tissue to deform flexibly in biochemical reaction and achieves contraction both at tissue and cell level. The contraction of tissue relieves the stress between cells under reaction to maintain cellular junctions even tight junctions are broken. Also, the drug perfusion test with antihistamine chemical is easily performed due to the connector part and properly inhibits the inflammatory reaction. Moreover, the traction force on endothelial cells is analyzed as about 0.9 µN on two types of scaffolds with different stiffness. It is believed that the potential of the flexible tissue model to reproduce biochemical reactions can contribute to the fabrication of vascular tissue models mimicking in vivo in high similarity as a platform for biomedical researches and pharmacokinetic testing.


Subject(s)
Hydrogels , Tissue Engineering , Blood Vessels , Collagen , Endothelial Cells , Tissue Scaffolds
6.
Sensors (Basel) ; 21(14)2021 Jul 15.
Article in English | MEDLINE | ID: mdl-34300568

ABSTRACT

We present fluorescent Janus hydrogel microbeads for continuous glucose sensing with pH calibration. The Janus hydrogel microbeads, that consist of fluorescent glucose and pH sensors, were fabricated with a UV-assisted centrifugal microfluidic device. The microbead can calibrate the pH values of its surroundings and enables accurate measurements of glucose within various pH conditions. As a proof of concept, we succeeded in obtaining the accurate value of glucose concentration in a body-fluid-like sample solution. We believe that our fluorescent microbeads, with pH calibration capability, could be applied to fully implantable sensors for continuous glucose monitoring.


Subject(s)
Blood Glucose Self-Monitoring , Hydrogels , Blood Glucose , Calibration , Glucose , Hydrogen-Ion Concentration , Microspheres
7.
Biotechnol Bioeng ; 118(10): 3760-3769, 2021 10.
Article in English | MEDLINE | ID: mdl-34110012

ABSTRACT

To generate three-dimensional tissue in vitro, promoting vasculogenesis in cell aggregates is an important factor. Here, we found that ultrasound promoted vasculogenesis of human umbilical vein endothelial cells (HUVECs). Promotion of HUVEC network formation and lumen formation were observed using our method. In addition to morphological evaluations, protein expression was quantified by western blot assays. As a result, expression of proteins related to vasculogenesis and the response to mechanical stress on cells was enhanced by exposure to ultrasound. Although several previous studies have shown that ultrasound may promote vasculogenesis, the effect of ultrasound was unclear because of unregulated ultrasound, the complex culture environment, or two-dimensional-cultured HUVECs that cannot form a lumen structure. In this study, regulated ultrasound was propagated on three-dimensional-monocultured HUVECs, which clarified the effect of ultrasound on vasculogenesis. We believe this finding may be an innovation in the tissue engineering field.


Subject(s)
Cell Culture Techniques , Human Umbilical Vein Endothelial Cells/metabolism , Neovascularization, Physiologic , Ultrasonic Waves , Human Umbilical Vein Endothelial Cells/cytology , Humans
8.
Biomed Microdevices ; 22(4): 81, 2020 11 17.
Article in English | MEDLINE | ID: mdl-33201329

ABSTRACT

Nerve guidance conduits (NGCs) composed of biocompatible polymers have been attracting attention as an alternative for autograft surgery in peripheral nerve regeneration. However, the nerve tissues repaired by NGCs often tend to be inadequate and lead to functional failure because of the lack of cellular supports. This paper presents a chitosan-collagen hydrogel conduit containing cells to induce peripheral nerve regeneration with cellular support. The conduit composed of two coaxial hydrogel layers of chitosan and collagen is simply made by molding and mechanical anchoring attachment with holes made on the hydrogel tube. A chitosan layer strengthens the conduit mechanically, and a collagen layer provides a scaffold for cells supporting the axonal extension. The conduits of different diameters (outer diameter approximately 2-4 mm) are fabricated. The conduit is bioabsorbable with lysozyme, and biocompatible even under bio absorption. In the neuron culture demonstration, the conduit containing Schwann cells induced the extension of the axon of neurons directed to the conduit. Our easily fabricated conduit could help the high-quality regeneration of peripheral nerves and contribute to the nerve repair surgery.


Subject(s)
Biocompatible Materials/chemistry , Biocompatible Materials/pharmacology , Chitosan/chemistry , Collagen/chemistry , Hydrogels/chemistry , Nerve Regeneration/drug effects , Peripheral Nerves/physiology , Capsules , Peripheral Nerves/cytology , Schwann Cells/cytology , Tissue Engineering
9.
Biomicrofluidics ; 14(4): 044106, 2020 Jul.
Article in English | MEDLINE | ID: mdl-32699566

ABSTRACT

We present an extracellular matrix (ECM)-based gradient generator that provides a culture surface with continuous chemical concentration gradients created by interstitial flow. The gelatin-based microchannels harboring gradient generators and in-channel micromixers were rapidly fabricated by sacrificial molding of a 3D-printed water-soluble sacrificial mold. When fluorescent dye solutions were introduced into the channel, the micromixers enhanced mixing of two solutions joined at the junction. Moreover, the concentration gradients generated in the channel diffused to the culture surface of the device through the interstitial space facilitated by the porous nature of the ECM. To check the functionality of the gradient generator for investigating cellular responses to chemical factors, we demonstrated that human umbilical vein endothelial cells cultured on the surface shrunk in response to the concentration gradient of histamine generated by interstitial flow from the microchannel. We believe that our device could be useful for the basic biological study of the cellular response to chemical stimuli and for the in vitro platform in drug testing.

10.
Lab Chip ; 20(11): 1917-1927, 2020 06 02.
Article in English | MEDLINE | ID: mdl-32307467

ABSTRACT

We present an extracellular matrix (ECM)-based stretchable microfluidic system for culturing in vitro three-dimensional (3D) vascular tissues, which mimics in vivo blood vessels. Human umbilical vein endothelial cells (HUVECs) can be cultured under perfusion and stretch simultaneously with real-time imaging by our proposed system. Our ECM (transglutaminase (TG) cross-linked gelatin)-based microchannel was fabricated by dissolving water-soluble sacrificial polyvinyl alcohol (PVA) molds printed with a 3D printer. Flows in the microchannel were analyzed under perfusion and stretch. We demonstrated simultaneous perfusion and stretch of TG gelatin-based microchannels culturing HUVECs. We suggest that our TG gelatin-based stretchable microfluidic system proves to be a useful tool for understanding the mechanisms of vascular tissue formation and mechanotransduction.


Subject(s)
Extracellular Matrix , Mechanotransduction, Cellular , Gelatin , Human Umbilical Vein Endothelial Cells , Humans , Perfusion
11.
Biofabrication ; 11(1): 015010, 2018 11 30.
Article in English | MEDLINE | ID: mdl-30499456

ABSTRACT

In vitro perfusable 3D tissue models mimic in vivo tissues and have several benefits in drug testing. However, processes used to fabricate these models often tend to be complicated. Here, we present a double-layer perfusable collagen tube device for multilayered in vitro 3D cell culture. The device is simply made by the repetition of a molding process. The thicknesses of the collagen layers in the tube device can be flexibly designed, and heterogeneous cell types can be co-cultured in/on each collagen layer. Moreover, while our collagen tube is directly attached to silicone tubes, the collagen tube can easily be connected to an external pump system for perfusion culture. We fabricated six different sizes of collagen devices (inner diameter approximately 300-1000 µm) using different molds, and successfully controlled the coefficients of variation to be below 5% for the diameters of each layer for all six device sizes. The device is strong enough to manipulate with tweezers, and can remain stable for more than 3 months in a medium. For the cell culture, we successfully and correctly encapsulated cells in the layer shape at the desired position, and confirmed cell migration. Using the perfusion culture, we demonstrated that the alignments of the HUVEC actin filaments become parallel to the flow direction. We believe that our device could advance the easy fabrication of various tissue models (that is, models mimicking in vivo tissues). In particular, the device could help fabricate vascularized tissue models, and contribute to the development of pharmacokinetic testing platforms and regenerative medicine.


Subject(s)
Cell Culture Techniques/instrumentation , Collagen/chemistry , Human Umbilical Vein Endothelial Cells/cytology , Pericytes/cytology , Tissue Engineering/instrumentation , Tissue Scaffolds/chemistry , Animals , Cattle , Cell Proliferation , Cells, Cultured , Humans
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