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2. Construction of Tough Hydrogel Cross-Linked via Ionic Interaction by Protection Effect of Hydrophobic Domains

Author

Bunuasunthon, Sukulya, Nakamoto, Masahiko, Hoven, Voravee P., and Matsusaki, Michiya

Abstract

Most hydrogels have poor mechanical properties, severely limiting their potential applications, and numerous approaches have been introduced to fabricate more robust and durable examples. However, these systems consist of nonbiodegradable polymers which limit their application in tissue engineering. Herein, we focus on the fabrication and investigate the influence of hydrophobic segments on ionic cross-linking properties for the construction of a tough, biodegradable hydrogel. A biodegradable, poly(γ-glutamic acid) polymer conjugated with a hydrophobic amino acid, l-phenylalanine ethyl ester (Phe), together with an ionic cross-linking group, alendronic acid (Aln) resulting in γ-PGA-Aln-Phe, was initially synthesized. Rheological assessments through time sweep oscillation testing revealed that the presence of hydrophobic domains accelerated gelation. Comparing gels with and without hydrophobic domains, the compressive strength of γ-PGA-Aln-Phe was found to be six times higher and exhibited longer stability properties in ethylenediaminetetraacetic acid solution, lasting for up to a month. Significantly, the contribution of the hydrophobic domains to the mechanical strength and stability of ionic cross-linking properties of the gel was found to be the dominant factor for the fabrication of a tough hydrogel. As a result, this study provides a new strategy for mechanical enhancement and preserves ionic cross-linked sites by the addition of hydrophobic domains. The development of tough, biodegradable hydrogels reported herein will open up new possibilities for applications in the field of biomaterials.

Published
2024
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5. Engineering metabolic cycle-inspired hydrogels with enzyme-fueled programmable transient volume changes.

Author

Hong, Young Kyoung, Nakamoto, Masahiko, and Matsusaki, Michiya

Abstract

An enzyme-fueled transient volume phase transition (TVPT) of hydrogels under out-of-equilibrium conditions is reported. The approach takes inspiration from the metabolic cycle, comprising nutrient intake and anabolism/catabolism followed by waste excretion. The incorporation of methacrylic acid and acrylated trypsin in a polymeric hydrogel allowed the TVPT of the gel to be fueled by lysozyme. With the intake of lysozyme as fuel, the construction/destruction of electrostatic cross-linkages induced transient shrinkage/swelling of the gel accompanied by the depletion of lysozyme activity. The system's transient response could be flexibly programmed by adjusting not only the fuel concentration but the chemical composition of materials. The lysozyme-fueled TVPT of the gel could be exploited to transient changes in the mechanical properties of the gel. Our work opens a route toward a new class of stimuli-responsive hydrogels for biomedical applications. [ABSTRACT FROM AUTHOR]

Published
2023
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10. Expertise Modeling for Automated Planning of Acetabular Cup in Total Hip Arthroplasty Using Combined Bone and Implant Statistical Atlases

Author

Otomaru, Itaru, Kobayashi, Kazuto, Okada, Toshiyuki, Nakamoto, Masahiko, Kagiyama, Yoshiyuki, Takao, Masaki, Sugano, Nobuhiko, Tada, Yukio, Sato, Yoshinobu, Hutchison, David, Series editor, Kanade, Takeo, Series editor, Kittler, Josef, Series editor, Kleinberg, Jon M., Series editor, Mattern, Friedemann, Series editor, Mitchell, John C., Series editor, Naor, Moni, Series editor, Nierstrasz, Oscar, Series editor, Pandu Rangan, C., Series editor, Steffen, Bernhard, Series editor, Sudan, Madhu, Series editor, Terzopoulos, Demetri, Series editor, Tygar, Doug, Series editor, Vardi, Moshe Y., Series editor, Weikum, Gerhard, Series editor, Yang, Guang-Zhong, editor, Hawkes, David, editor, Rueckert, Daniel, editor, Noble, Alison, editor, and Taylor, Chris, editor

Published
2009
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11. Construction of a Statistical Surgical Plan Atlas for Automated 3D Planning of Femoral Component in Total Hip Arthroplasty

Author

Nakamoto, Masahiko, Otomaru, Itaru, Takao, Masaki, Sugano, Nobuhiko, Kagiyama, Yoshiyuki, Yoshikawa, Hideki, Tada, Yukio, Sato, Yoshinobu, Hutchison, David, Series editor, Kanade, Takeo, Series editor, Kittler, Josef, Series editor, Kleinberg, Jon M., Series editor, Mattern, Friedemann, Series editor, Mitchell, John C., Series editor, Naor, Moni, Series editor, Nierstrasz, Oscar, Series editor, Pandu Rangan, C., Series editor, Steffen, Bernhard, Series editor, Sudan, Madhu, Series editor, Terzopoulos, Demetri, Series editor, Tygar, Doug, Series editor, Vardi, Moshe Y., Series editor, Weikum, Gerhard, Series editor, Metaxas, Dimitris, editor, Axel, Leon, editor, Fichtinger, Gabor, editor, and Székely, Gábor, editor

Published
2008
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12. Construction of Hierarchical Multi-Organ Statistical Atlases and Their Application to Multi-Organ Segmentation from CT Images

Author

Okada, Toshiyuki, Yokota, Keita, Hori, Masatoshi, Nakamoto, Masahiko, Nakamura, Hironobu, Sato, Yoshinobu, Hutchison, David, editor, Kanade, Takeo, editor, Kittler, Josef, editor, Kleinberg, Jon M., editor, Mattern, Friedemann, editor, Mitchell, John C., editor, Naor, Moni, editor, Nierstrasz, Oscar, editor, Pandu Rangan, C., editor, Steffen, Bernhard, editor, Sudan, Madhu, editor, Terzopoulos, Demetri, editor, Tygar, Doug, editor, Vardi, Moshe Y., editor, Weikum, Gerhard, editor, Metaxas, Dimitris, editor, Axel, Leon, editor, Fichtinger, Gabor, editor, and Székely, Gábor, editor

Published
2008
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13. Automated Preoperative Planning of Femoral Component for Total Hip Arthroplasty (THA) from 3D CT Images

Author

Otomaru, Itaru, Nakamoto, Masahiko, Takao, Masaki, Sugano, Nobuhiko, Kagiyama, Yoshiyuki, Yoshikawa, Hideki, Tada, Yukio, Sato, Yoshinobu, Hutchison, David, editor, Kanade, Takeo, editor, Kittler, Josef, editor, Kleinberg, Jon M., editor, Mattern, Friedemann, editor, Mitchell, John C., editor, Naor, Moni, editor, Nierstrasz, Oscar, editor, Pandu Rangan, C., editor, Steffen, Bernhard, editor, Sudan, Madhu, editor, Terzopoulos, Demetri, editor, Tygar, Doug, editor, Vardi, Moshe Y., editor, Weikum, Gerhard, editor, Dohi, Takeyoshi, editor, Sakuma, Ichiro, editor, and Liao, Hongen, editor

Published
2008
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14. Realtime Organ Tracking for Endoscopic Augmented Reality Visualization Using Miniature Wireless Magnetic Tracker

Author

Nakamoto, Masahiko, Ukimura, Osamu, Gill, Inderbir S., Mahadevan, Arul, Miki, Tsuneharu, Hashizume, Makoto, Sato, Yoshinobu, Hutchison, David, editor, Kanade, Takeo, editor, Kittler, Josef, editor, Kleinberg, Jon M., editor, Mattern, Friedemann, editor, Mitchell, John C., editor, Naor, Moni, editor, Nierstrasz, Oscar, editor, Pandu Rangan, C., editor, Steffen, Bernhard, editor, Sudan, Madhu, editor, Terzopoulos, Demetri, editor, Tygar, Doug, editor, Vardi, Moshe Y., editor, Weikum, Gerhard, editor, Dohi, Takeyoshi, editor, Sakuma, Ichiro, editor, and Liao, Hongen, editor

Published
2008
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15. Thoracoscopic Surgical Navigation System for Cancer Localization in Collapsed Lung Based on Estimation of Lung Deformation

Author

Nakamoto, Masahiko, Aburaya, Naoki, Sato, Yoshinobu, Konishi, Kozo, Yoshino, Ichiro, Hashizume, Makoto, Tamura, Shinichi, Hutchison, David, editor, Kanade, Takeo, editor, Kittler, Josef, editor, Kleinberg, Jon M., editor, Mattern, Friedemann, editor, Mitchell, John C., editor, Naor, Moni, editor, Nierstrasz, Oscar, editor, Pandu Rangan, C., editor, Steffen, Bernhard, editor, Sudan, Madhu, editor, Terzopoulos, Demetri, editor, Tygar, Doug, editor, Vardi, Moshe Y., editor, Weikum, Gerhard, editor, Ayache, Nicholas, editor, Ourselin, Sébastien, editor, and Maeder, Anthony, editor

Published
2007
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16. Automated Segmentation of the Liver from 3D CT Images Using Probabilistic Atlas and Multi-level Statistical Shape Model

Author

Okada, Toshiyuki, Shimada, Ryuji, Sato, Yoshinobu, Hori, Masatoshi, Yokota, Keita, Nakamoto, Masahiko, Chen, Yen-Wei, Nakamura, Hironobu, Tamura, Shinichi, Hutchison, David, editor, Kanade, Takeo, editor, Kittler, Josef, editor, Kleinberg, Jon M., editor, Mattern, Friedemann, editor, Mitchell, John C., editor, Naor, Moni, editor, Nierstrasz, Oscar, editor, Pandu Rangan, C., editor, Steffen, Bernhard, editor, Sudan, Madhu, editor, Terzopoulos, Demetri, editor, Tygar, Doug, editor, Vardi, Moshe Y., editor, Weikum, Gerhard, editor, Ayache, Nicholas, editor, Ourselin, Sébastien, editor, and Maeder, Anthony, editor

Published
2007
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17. Recovery of Liver Motion and Deformation Due to Respiration Using Laparoscopic Freehand 3D Ultrasound System

Author

Nakamoto, Masahiko, Hirayama, Hiroaki, Sato, Yoshinobu, Konishi, Kozo, Kakeji, Yoshihiro, Hashizume, Makoto, Tamura, Shinichi, Hutchison, David, editor, Kanade, Takeo, editor, Kittler, Josef, editor, Kleinberg, Jon M., editor, Mattern, Friedemann, editor, Mitchell, John C., editor, Naor, Moni, editor, Nierstrasz, Oscar, editor, Pandu Rangan, C., editor, Steffen, Bernhard, editor, Sudan, Madhu, editor, Terzopoulos, Demetri, editor, Tygar, Dough, editor, Vardi, Moshe Y., editor, Weikum, Gerhard, editor, Larsen, Rasmus, editor, Nielsen, Mads, editor, and Sporring, Jon, editor

Published
2006
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19. Camera Model and Calibration Procedure for Oblique-Viewing Endoscope

Author

Yamaguchi, Tetsuzo, Nakamoto, Masahiko, Sato, Yoshinobu, Nakajima, Yoshikazu, Konishi, Kozo, Hashizume, Makoto, Nishii, Takashi, Sugano, Nobuhiko, Yoshikawa, Hideki, Yonenobu, Kazuo, Tamura, Shinichi, Goos, Gerhard, editor, Hartmanis, Juris, editor, van Leeuwen, Jan, editor, Ellis, Randy E., editor, and Peters, Terry M., editor

Published
2003
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22. Magneto-Optic Hybrid 3-D Sensor for Surgical Navigation

Author

Nakamoto, Masahiko, Sato, Yoshinobu, Tamaki, Yasuhiro, Nagano, Hiroaki, Miyamoto, Masaki, Sasama, Toshihiko, Monden, Morito, Tamura, Shinichi, Goos, Gerhard, editor, Hartmanis, Juris, editor, van Leeuwen, Jan, editor, Delp, Scott L., editor, DiGoia, Anthony M., editor, and Jaramaz, Branislav, editor

Published
2000
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34. Intraoperative magnetic tracker calibration using a magneto-optic hybrid tracker for 3-D ultrasound-based navigation in laparoscopic surgery

Author

Nakamoto, Masahiko, Nakada, Kazuhisa, Sato, Yoshinobu, Konishi, Kozo, Hashizume, Makoto, and Tamura, Shinichi

Subjects
Laparoscopic surgery -- Equipment and supplies, Computer-aided design -- Research, Magnetic fields -- Properties, Diagnostic imaging -- Research, Business, Electronics, Electronics and electrical industries, Health care industry
Abstract

This paper describes a ultrasound (3-D US) system that aims to achieve augmented reality (AR) visualization during laparoscopic surgery, especially for the liver. To acquire 3-D US data of the liver, the tip of a laparoscopic ultrasound probe is tracked inside the abdominal cavity using a magnetic tracker. The accuracy of magnetic trackers, however, is greatly affected by magnetic field distortion that results from the close proximity of metal objects and electronic equipment, which is usually unavoidable in the operating room. In this paper, we describe a calibration method for intraoperative magnetic distortion that can be applied to laparoscopic 3-D US data acquisition; we evaluate the accuracy and feasibility of the method by in vitro and in vivo experiments. Although calibration data can be acquired freehand using a magneto-optic hybrid tracker, there are two problems associated with this method--error caused by the time delay between measurements of the optical and magnetic trackers, and instability of the calibration accuracy that results from the uniformity and density of calibration data. A temporal calibration procedure is developed to estimate the time delay, which is then integrated into the calibration, and a distortion model is formulated by zeroth-degree to fourth-degree polynomial fitting to the calibration data. In the in vivo experiment using a pig, the positional error caused by magnetic distortion was reduced from 44.1 to 2.9 mm. The standard deviation of corrected target positions was less than 1.0 mm. Freehand acquisition of calibration data was performed smoothly using a magneto-optic hybrid sampling tool through a trocar under guidance by realtime 3-D monitoring of the tool trajectory; data acquisition time was less than 2 min. The present study suggests that our proposed method could correct for magnetic field distortion inside the patient's abdomen during a laparoscopic procedure within a clinically permissible period of time, as well as enabling an accurate 3-D US reconstruction to be obtained that can be superimposed onto live endoscopic images. Index Terms--Accuracy validation, computer-assisted surgery, intrabody tracking, laparoscopic ultrasound, magnetic field distortion, temporal calibration.

Published
2008

47. ROBOTIC ZERO-ISCHEMIA PARTIAL NEPHRECTOMY FOR HILAR TUMORS: V398

Author

Leslie, Scott, de Castro Abreu, Andre Luis, Lewandowski, Pierre-Marie, Huang, Eric Yi-Hsui, Berger, Andre K., Jayaratna, Isuru, Nakamoto, Masahiko, Ng, Casey, Ukimura, Osamu, Aron, Monish, Gill, Inderbir S., and Desai, Mihir M.

Published
2012

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