Pub Date : 2009-12-11DOI: 10.1109/MHS.2009.5351959
E. Avci, K. Ohara, T. Takubo, Y. Mae, T. Arai
Micro robotics is a significant area to be able to manipulate micro level objects dexterously. Until now, various micro manipulation systems have been presented. In micro environment, different kinds of objects have different dimensions. Some of them are a few micrometers (µm) such as donor cells, some of them are more than a hundred µm such as egg cells. At this point, a manipulator which has multi-scale manipulation ability can manipulate different size objects. Otherwise, for different diameter objects, different micro-hands are necessary. Furthermore, when we want to manipulate micro objects, manipulation distance is not always same. Because, with micro hand, we do not just want to grasp or rotate the objects, sometimes we could also want to carry the object from one micro environment to another one. Therefore, workspace of micro manipulator is also important for various micro tasks. In this paper, we propose a new micro manipulation system which includes parallel mechanism for grasping and releasing tasks. This new system has ability of multi-scale manipulation, which means manipulation of different size objects with same micro hand. Moreover, short distance (nm) and long distances carriage (mm) are feasible with this micro manipulator.
{"title":"A new multi-scale micromanipulation system with dexterous motion","authors":"E. Avci, K. Ohara, T. Takubo, Y. Mae, T. Arai","doi":"10.1109/MHS.2009.5351959","DOIUrl":"https://doi.org/10.1109/MHS.2009.5351959","url":null,"abstract":"Micro robotics is a significant area to be able to manipulate micro level objects dexterously. Until now, various micro manipulation systems have been presented. In micro environment, different kinds of objects have different dimensions. Some of them are a few micrometers (µm) such as donor cells, some of them are more than a hundred µm such as egg cells. At this point, a manipulator which has multi-scale manipulation ability can manipulate different size objects. Otherwise, for different diameter objects, different micro-hands are necessary. Furthermore, when we want to manipulate micro objects, manipulation distance is not always same. Because, with micro hand, we do not just want to grasp or rotate the objects, sometimes we could also want to carry the object from one micro environment to another one. Therefore, workspace of micro manipulator is also important for various micro tasks. In this paper, we propose a new micro manipulation system which includes parallel mechanism for grasping and releasing tasks. This new system has ability of multi-scale manipulation, which means manipulation of different size objects with same micro hand. Moreover, short distance (nm) and long distances carriage (mm) are feasible with this micro manipulator.","PeriodicalId":344667,"journal":{"name":"2009 International Symposium on Micro-NanoMechatronics and Human Science","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131532167","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2009-12-11DOI: 10.1109/MHS.2009.5351913
K. Ui-Tei, K. Nishi, Y. Naito, S. Zenno, Aya Juni, K. Saigo
Previously, we showed that DNA replacement of the seed-containing region of class I siRNAs significantly reduced the off-target effect without substantial loss of target gene silencing activity (Ui-Tei et al, Nucleic Acids Res., 36, 2136–2151, 2008). Separately, we also showed that the level of the off-target effect due to non-modified class I siRNA is determined primarily by the calculated melting temperature (Tm) of the seed-target duplex, indicating that, at least in class I-siRNA-mediated gene silencing, Tm or thermodynamic stability of the complex between the siRNA seed and target mRNA is the most important factor determining the degree of off-target effects (Ui-Tei et al., Nucleic Acids Res., 36, 7100–7109, 2008). Here, using non-modified siRNAs other than class I siRNAs and DNA-seed-containing siRNAs, we examined the relationship between the thermodynamic stability of the seed-target duplex and the degree of the off-target effect. We found that the degree of the off-target effects is generally determined primarily by the Tm of the corresponding seed-target duplex, indicating that its thermodynamic stability is the most important general determinant of the degree of the off-target effect in gene silencing.
{"title":"Reduced base-base interactions between the DNA seed and RNA target are the major determinants of a significant reduction in the off-target effect due to DNA-seed-containing siRNA","authors":"K. Ui-Tei, K. Nishi, Y. Naito, S. Zenno, Aya Juni, K. Saigo","doi":"10.1109/MHS.2009.5351913","DOIUrl":"https://doi.org/10.1109/MHS.2009.5351913","url":null,"abstract":"Previously, we showed that DNA replacement of the seed-containing region of class I siRNAs significantly reduced the off-target effect without substantial loss of target gene silencing activity (Ui-Tei et al, Nucleic Acids Res., 36, 2136–2151, 2008). Separately, we also showed that the level of the off-target effect due to non-modified class I siRNA is determined primarily by the calculated melting temperature (Tm) of the seed-target duplex, indicating that, at least in class I-siRNA-mediated gene silencing, Tm or thermodynamic stability of the complex between the siRNA seed and target mRNA is the most important factor determining the degree of off-target effects (Ui-Tei et al., Nucleic Acids Res., 36, 7100–7109, 2008). Here, using non-modified siRNAs other than class I siRNAs and DNA-seed-containing siRNAs, we examined the relationship between the thermodynamic stability of the seed-target duplex and the degree of the off-target effect. We found that the degree of the off-target effects is generally determined primarily by the Tm of the corresponding seed-target duplex, indicating that its thermodynamic stability is the most important general determinant of the degree of the off-target effect in gene silencing.","PeriodicalId":344667,"journal":{"name":"2009 International Symposium on Micro-NanoMechatronics and Human Science","volume":"195 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132404437","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2009-12-11DOI: 10.1109/MHS.2009.5351857
Y. Kurata, N. Suzuki, R. Hino, E. Shamoto
Chatter vibration in milling often results in poor surface finish and rapid tool wear, consequently limiting productivity. Thus, chatter suppression is one of the most important themes in industry. Self-excited chatter vibration in milling is generally caused by two kinds of mechanisms, i.e., regeneration and mode-coupling, and both mechanisms should be handled simultaneously to suppress the chatter vibration. Since the mode-coupling can be restricted by separating the natural frequencies of the vibration modes, it has been considered that use of an anisotropic rotating tool is effective on suppressing the chatter vibration in milling. However, the practical effects of the several parameters have not been revealed because it was difficult to predict the chatter stability accurately. On the other hand, the accurate analytical model of the milling process with the anisotropic rotating tool have been developed and verified experimentally by the authors. In order to reveal the practical chatter suppression effect of the anisotropic rotation tool, several cutting conditions, i.e., the immersion angle, the spindle speed and the number of flutes, on the chatter stability are investigated with the developed analytical model in the present study. By comparing the analytical results, it is confirmed that the mode-coupling is restricted and the stability limit in the axial depth of cut increases especially within the low spindle speed range by using the anisotropic rotating tool. The chatter suppression effect also depends on the radial depth of cut considerably. The relationships between the tool conditions, such as the difference of the natural frequencies and flute's angular position, and the chatter suppression effect are also investigated, and it is revealed that both affect the chatter stability significantly.
{"title":"Chatter suppression in milling with anisotropic tools","authors":"Y. Kurata, N. Suzuki, R. Hino, E. Shamoto","doi":"10.1109/MHS.2009.5351857","DOIUrl":"https://doi.org/10.1109/MHS.2009.5351857","url":null,"abstract":"Chatter vibration in milling often results in poor surface finish and rapid tool wear, consequently limiting productivity. Thus, chatter suppression is one of the most important themes in industry. Self-excited chatter vibration in milling is generally caused by two kinds of mechanisms, i.e., regeneration and mode-coupling, and both mechanisms should be handled simultaneously to suppress the chatter vibration. Since the mode-coupling can be restricted by separating the natural frequencies of the vibration modes, it has been considered that use of an anisotropic rotating tool is effective on suppressing the chatter vibration in milling. However, the practical effects of the several parameters have not been revealed because it was difficult to predict the chatter stability accurately. On the other hand, the accurate analytical model of the milling process with the anisotropic rotating tool have been developed and verified experimentally by the authors. In order to reveal the practical chatter suppression effect of the anisotropic rotation tool, several cutting conditions, i.e., the immersion angle, the spindle speed and the number of flutes, on the chatter stability are investigated with the developed analytical model in the present study. By comparing the analytical results, it is confirmed that the mode-coupling is restricted and the stability limit in the axial depth of cut increases especially within the low spindle speed range by using the anisotropic rotating tool. The chatter suppression effect also depends on the radial depth of cut considerably. The relationships between the tool conditions, such as the difference of the natural frequencies and flute's angular position, and the chatter suppression effect are also investigated, and it is revealed that both affect the chatter stability significantly.","PeriodicalId":344667,"journal":{"name":"2009 International Symposium on Micro-NanoMechatronics and Human Science","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131215077","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2009-12-11DOI: 10.1109/MHS.2009.5351955
H. Ogasawara, A. Kori, Kayoko Yamada, Kaneyoshi Yamamoto, A. Ishihama
Under stressful conditions in nature, Escherichia coli forms biofilms for long-term survival. Curli fimbriae are an essential architecture for cell-cell contacts within biofilms. Structural components and assembly factors of curli are encoded by two divergently arranged operons, csgBA and csgDEFG, which are regulated by the csgD gene product. Thus, CsgD is a master regulator of bacterial biofilm formation. Reflecting the response of biofilm formation to various external factors and conditions, the csgD promoter is under the control of multiple transcription factors including CRP, CpxR, Crl, H-NS, IHF, MlrA, OmpR, RcsB and RstA. We have conducted a systematic analysis of the regulation mechanism of the csgD promoter by these multiple transcription factors. After the DNA binding assays in vitro of various combinations of these factors with various segments of the csgD promoter as DNA probes, we realized not only competition between positive and negative regulators but also cooperative interplay within both positive and negative factor groups. These findings raise a regulation model, in which the csgD promoter is controlled by the relative levels of functional molecules of these transcription factors.
{"title":"Regulation of the E. coli csgD gene encoding the master regulator of biofilm formation: Interplay between multiple transcription factors","authors":"H. Ogasawara, A. Kori, Kayoko Yamada, Kaneyoshi Yamamoto, A. Ishihama","doi":"10.1109/MHS.2009.5351955","DOIUrl":"https://doi.org/10.1109/MHS.2009.5351955","url":null,"abstract":"Under stressful conditions in nature, Escherichia coli forms biofilms for long-term survival. Curli fimbriae are an essential architecture for cell-cell contacts within biofilms. Structural components and assembly factors of curli are encoded by two divergently arranged operons, csgBA and csgDEFG, which are regulated by the csgD gene product. Thus, CsgD is a master regulator of bacterial biofilm formation. Reflecting the response of biofilm formation to various external factors and conditions, the csgD promoter is under the control of multiple transcription factors including CRP, CpxR, Crl, H-NS, IHF, MlrA, OmpR, RcsB and RstA. We have conducted a systematic analysis of the regulation mechanism of the csgD promoter by these multiple transcription factors. After the DNA binding assays in vitro of various combinations of these factors with various segments of the csgD promoter as DNA probes, we realized not only competition between positive and negative regulators but also cooperative interplay within both positive and negative factor groups. These findings raise a regulation model, in which the csgD promoter is controlled by the relative levels of functional molecules of these transcription factors.","PeriodicalId":344667,"journal":{"name":"2009 International Symposium on Micro-NanoMechatronics and Human Science","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133101552","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2009-12-11DOI: 10.1109/MHS.2009.5351899
Motoshi Suzuki, Y. Kamei, S. Yuba, S. Takagi
Methods for turning on/off gene expression at any desired time and place in vivo would be useful for analyzing various biological processes. We have developed a novel microscopic system utilizing an infrared laser, IR-LEGO (infrared-laser evoked gene operator), which is designed to deposit heat locally in living organisms. We have shown that IR-LEGO enables us to induce the heat shock response efficiently in targeted single cells of C. elegans worms, thereby driving expression of a transgene under the control of a heat shock promoter. By using IR-LEGO we attempted to rescue several mutant phenotypes of worms at the single-cell level. Diverse cell behaviors including differentiation and migration of target cells can be manipulated by gene induction mediated by IR-LEGO. Our results showed that IR-LEGO can be used to manipulate cell-autonomous as well as cell-nonautonomous behaviors, further confirming that irradiation using IR-LEGO has no harmful effects on the targets. Thus, IR-LEGO serves as valuable tools for manipulating biological processes in living organisms.
{"title":"Manipulating behaviors of targeted single cells in vivo by using IR-LEGO","authors":"Motoshi Suzuki, Y. Kamei, S. Yuba, S. Takagi","doi":"10.1109/MHS.2009.5351899","DOIUrl":"https://doi.org/10.1109/MHS.2009.5351899","url":null,"abstract":"Methods for turning on/off gene expression at any desired time and place in vivo would be useful for analyzing various biological processes. We have developed a novel microscopic system utilizing an infrared laser, IR-LEGO (infrared-laser evoked gene operator), which is designed to deposit heat locally in living organisms. We have shown that IR-LEGO enables us to induce the heat shock response efficiently in targeted single cells of C. elegans worms, thereby driving expression of a transgene under the control of a heat shock promoter. By using IR-LEGO we attempted to rescue several mutant phenotypes of worms at the single-cell level. Diverse cell behaviors including differentiation and migration of target cells can be manipulated by gene induction mediated by IR-LEGO. Our results showed that IR-LEGO can be used to manipulate cell-autonomous as well as cell-nonautonomous behaviors, further confirming that irradiation using IR-LEGO has no harmful effects on the targets. Thus, IR-LEGO serves as valuable tools for manipulating biological processes in living organisms.","PeriodicalId":344667,"journal":{"name":"2009 International Symposium on Micro-NanoMechatronics and Human Science","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130773479","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2009-12-11DOI: 10.1109/MHS.2009.5352063
P. Levi
Symbiotic robotics is a discipline within collective robotics that is concerned with artificial multi-cellular robot-organisms that define their morphological structure by aggregation through self-assembling and they are also able to disaggregate afterwards. This contribution is concerned to the description of evolutionary and cognitive principles that governs such a symbiotic cycle to build artificial organisms of different forms and operate with them. The evolutionary approach starts with a artificial genome, will be continued by the insertion of different types of regulative cycles, and ends up in an embryogenetic formed body. Hereby there is differentiation between the genetic based learning and the fitness based learning. Further there are dominant differences between multi-cellular organism and structured cooperative aggregations of swarm members. The cognitive approach is focused on cognitive maps, on cognitive sensor data fusion and finally to the definition of information that governs the the process of organism formation and body survival in a given environment. This more engineering oriented approach is used to build all HW-components and all kinds of embedded “operating systems” to control and to operate symbiotic robot organisms.
{"title":"Development of evolutionary and self-assembling robot-organisms","authors":"P. Levi","doi":"10.1109/MHS.2009.5352063","DOIUrl":"https://doi.org/10.1109/MHS.2009.5352063","url":null,"abstract":"Symbiotic robotics is a discipline within collective robotics that is concerned with artificial multi-cellular robot-organisms that define their morphological structure by aggregation through self-assembling and they are also able to disaggregate afterwards. This contribution is concerned to the description of evolutionary and cognitive principles that governs such a symbiotic cycle to build artificial organisms of different forms and operate with them. The evolutionary approach starts with a artificial genome, will be continued by the insertion of different types of regulative cycles, and ends up in an embryogenetic formed body. Hereby there is differentiation between the genetic based learning and the fitness based learning. Further there are dominant differences between multi-cellular organism and structured cooperative aggregations of swarm members. The cognitive approach is focused on cognitive maps, on cognitive sensor data fusion and finally to the definition of information that governs the the process of organism formation and body survival in a given environment. This more engineering oriented approach is used to build all HW-components and all kinds of embedded “operating systems” to control and to operate symbiotic robot organisms.","PeriodicalId":344667,"journal":{"name":"2009 International Symposium on Micro-NanoMechatronics and Human Science","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130721777","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2009-12-11DOI: 10.1109/MHS.2009.5351788
P. Pal, Kazuo Sato
The present research reports the fabrication techniques for the formation of complex three dimensional structures. The process is developed using very economic wet anisotropic etching in pure and surfactant Triton X−100 [C14H22O(C2H4O)n, n= 9–10] added 25 wt% tetramethyl ammonium hydroxide (TMAH) solutions. The structures are fabricated in single and nitride-based silicon on insulator (SOI) Si{100} wafers. In single wafer, both fixed and suspended structures are manufactured, while in SOI wafers only freestanding structures are realized. The present research is aimed to enhance the range of 3D structures fabricated using wet etching.
{"title":"Wet etched complex three dimensional MEMS structures","authors":"P. Pal, Kazuo Sato","doi":"10.1109/MHS.2009.5351788","DOIUrl":"https://doi.org/10.1109/MHS.2009.5351788","url":null,"abstract":"The present research reports the fabrication techniques for the formation of complex three dimensional structures. The process is developed using very economic wet anisotropic etching in pure and surfactant Triton X−100 [C<inf>14</inf>H<inf>22</inf>O(C<inf>2</inf>H<inf>4</inf>O)<inf>n</inf>, n= 9–10] added 25 wt% tetramethyl ammonium hydroxide (TMAH) solutions. The structures are fabricated in single and nitride-based silicon on insulator (SOI) Si{100} wafers. In single wafer, both fixed and suspended structures are manufactured, while in SOI wafers only freestanding structures are realized. The present research is aimed to enhance the range of 3D structures fabricated using wet etching.","PeriodicalId":344667,"journal":{"name":"2009 International Symposium on Micro-NanoMechatronics and Human Science","volume":"254 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134490349","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2009-12-11DOI: 10.1109/MHS.2009.5351868
K. Takiguchi, M. Negishi, Y. Tanaka-Takiguchi, M. Homma, K. Yoshikawa
Using a spontaneous transfer method, cell-sized giant liposomes encapsulating desired amounts of actoHMM, a mixture of actin filament (F-actin) and heavy meromyosin (HMM, an actin-related molecular motor), have been successfully constructed in the presence of 5 mM MgCl2 and 50 mM KCl. The encapsulated actoHMM formed self-organized actin network-like structures, and non-spherical liposomes were obtained in a reproducible manner. In order to power the system with actoHMM in an effective manner, we have tried to supply ATP through protein pores embedded in the closed bilayer membrane. By the ATP supply, the network structures of F-actin formed inside the liposomes showed redistributions, which are attributable to the sliding between F-actin and HMM. This study serves as the first step in developing motile giant liposomes containing actoHMM, and in generating spontaneous motion in a system similar manner as in living cells.
{"title":"Real-world modeling of artificial motile cell","authors":"K. Takiguchi, M. Negishi, Y. Tanaka-Takiguchi, M. Homma, K. Yoshikawa","doi":"10.1109/MHS.2009.5351868","DOIUrl":"https://doi.org/10.1109/MHS.2009.5351868","url":null,"abstract":"Using a spontaneous transfer method, cell-sized giant liposomes encapsulating desired amounts of actoHMM, a mixture of actin filament (F-actin) and heavy meromyosin (HMM, an actin-related molecular motor), have been successfully constructed in the presence of 5 mM MgCl2 and 50 mM KCl. The encapsulated actoHMM formed self-organized actin network-like structures, and non-spherical liposomes were obtained in a reproducible manner. In order to power the system with actoHMM in an effective manner, we have tried to supply ATP through protein pores embedded in the closed bilayer membrane. By the ATP supply, the network structures of F-actin formed inside the liposomes showed redistributions, which are attributable to the sliding between F-actin and HMM. This study serves as the first step in developing motile giant liposomes containing actoHMM, and in generating spontaneous motion in a system similar manner as in living cells.","PeriodicalId":344667,"journal":{"name":"2009 International Symposium on Micro-NanoMechatronics and Human Science","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123770303","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2009-12-11DOI: 10.1109/MHS.2009.5352045
T. Hamada, K. Ishii, Ryoko Sugimoto, T. Nagasaki, M. Takagi
By using a synthetic photosensitive amphiphile containing azobenzene (KAON12), we developed a method for the photo-manipulation of lipid membrane morphology, in which the shape of a vesicle can be switched by light. Cell-sized liposomes are prepared from KAON12 and 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC). We conducted real-time observations of vesicular transformation in the photo-sensitive liposome by phase-contrast microscopy, and found that membrane budding transitions could be controlled by light. These transformations can be interpreted in terms of the change in the effective membrane surface area due to photoisomerization of the constituent molecules. We discuss the mechanism by considering the elastic free energy of the membranes.
{"title":"Photochemical control on morphologies of a cell-sized synthetic vesicle","authors":"T. Hamada, K. Ishii, Ryoko Sugimoto, T. Nagasaki, M. Takagi","doi":"10.1109/MHS.2009.5352045","DOIUrl":"https://doi.org/10.1109/MHS.2009.5352045","url":null,"abstract":"By using a synthetic photosensitive amphiphile containing azobenzene (KAON12), we developed a method for the photo-manipulation of lipid membrane morphology, in which the shape of a vesicle can be switched by light. Cell-sized liposomes are prepared from KAON12 and 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC). We conducted real-time observations of vesicular transformation in the photo-sensitive liposome by phase-contrast microscopy, and found that membrane budding transitions could be controlled by light. These transformations can be interpreted in terms of the change in the effective membrane surface area due to photoisomerization of the constituent molecules. We discuss the mechanism by considering the elastic free energy of the membranes.","PeriodicalId":344667,"journal":{"name":"2009 International Symposium on Micro-NanoMechatronics and Human Science","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130113955","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2009-12-11DOI: 10.1109/MHS.2009.5351980
O. Mazda, T. Kishida, M. Matsui, H. Nakano, Koichiro Yoshimoto, Taketoshi Shimada, S. Nakai, Jiro Imanishr, Y. Hisa
Genetic transfection is a fundamental technology required for analysis and control of cells and tissues. The efficiency of gene transfection is drastically improved by using Epstein-Barr virus (EBV) nuclear antigen 1 (EBNA1) gene and oriP, which are derived from EBV genome, as components of plasmid vectors to be combined with various non-viral gene transfer vehicles. By means of the multiscale manipulation procedures, we analyzed intracellular distribution of EBNA1 and oriP sequence after transfected the EBNA1/oriP-bearing plasmid vectors (EBV-based episomal vectors) after transfected into mammalian cells, and estimated its implication to the high rate transfection of the EBV-based episomal vectors. Because the EBNA1 plays pleiotrophic roles in transfected cells, we also evaluated contribution of each function of the molecule to the transfection and expression efficiency of the vectors. Beside these studies on basic aspects of the EBNA1/oriP system, we assessed possible application of the EBV-based episomal vectors to regenerative medicine and gene therapy. For example, in vivo activities of various cytokines were tested in normal as well as diseased animals by transfecting them in vivo with the EBV-based episomal vectors carrying expression units for the cytokine genes. Thus, systemic administration of the interleukin-27 (IL-27) gene into the mice that had been transplanted with squamous cell carcinoma resulted in significant suppression of the growth of the tumor, which was mediated by the cooperation of the tumor-specific IgG antibody that was induced by IL-27 and the natural killer (NK) cells of which cytotoxic activity was also enhanced by the cytokine. IL-28 gene also suppressed the tumor in the similar experimental setting using the squamous cell carcinoma, but unlike the mechanism of IL-27-mediated anti-tumor effect, the tumor inhibition resulted from IL-28 gene transfer may be mediated by induction of the cytotoxic T lymphocytes, while coadministration of a chemotherapeutic agent significantly enhanced the IL-28-mediated tumor suppression. There findings may propose novel gene therapy and immunotherapy procedures to concur malignancies, while the highly efficient and long-term persistent exogenous gene expression accomplished by the EBV-based episomal vector may also provide a powerful means for stem cell study and regenerative medicine for human diseases.
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