Pub Date : 2020-07-02DOI: 10.1080/1358314x.2020.1855919
S. Ustunel, M. Prévôt, R. Clements, E. Hegmann
ABSTRACT Undeniably cell culture plays an important role in biomedical and biological research from understanding cell metabolic pathways to drug screening processes. Traditional cell cultures have been two dimensional (2D) planar (cells growing only in monolayers) and at times frustratedly static. Due to the limitations of 2D cultures, most research has moved towards more complex and dynamic three dimensional (3D) systems that both academic and biomedical research have quickly adopted allowing for wider cell culture applications not feasible using 2D systems. Most 3D cell scaffolds are made using techniques such as particle leaching, or gas foaming methods among others. These approaches present some restrictions, mainly across geometric constraints with deficiencies in the control of pore size, secondary structure and interconnectivity. Other constraints include properly assessing if the materials in question are truly biocompatible and will allow for long term cell studies. Last but not least, mechanical properties of the prepared materials must match cell and tissue specific needs that will lead to correct cellular orientation. In this review we will focus on the key issues that need to be taken into consideration when reporting a new material as biocompatible and biodegradable to ensure reproducibility and rigor when designing novel scaffolds.
{"title":"Cradle-to-cradle: designing biomaterials to fit as truly biomimetic cell scaffolds– a review","authors":"S. Ustunel, M. Prévôt, R. Clements, E. Hegmann","doi":"10.1080/1358314x.2020.1855919","DOIUrl":"https://doi.org/10.1080/1358314x.2020.1855919","url":null,"abstract":"ABSTRACT Undeniably cell culture plays an important role in biomedical and biological research from understanding cell metabolic pathways to drug screening processes. Traditional cell cultures have been two dimensional (2D) planar (cells growing only in monolayers) and at times frustratedly static. Due to the limitations of 2D cultures, most research has moved towards more complex and dynamic three dimensional (3D) systems that both academic and biomedical research have quickly adopted allowing for wider cell culture applications not feasible using 2D systems. Most 3D cell scaffolds are made using techniques such as particle leaching, or gas foaming methods among others. These approaches present some restrictions, mainly across geometric constraints with deficiencies in the control of pore size, secondary structure and interconnectivity. Other constraints include properly assessing if the materials in question are truly biocompatible and will allow for long term cell studies. Last but not least, mechanical properties of the prepared materials must match cell and tissue specific needs that will lead to correct cellular orientation. In this review we will focus on the key issues that need to be taken into consideration when reporting a new material as biocompatible and biodegradable to ensure reproducibility and rigor when designing novel scaffolds.","PeriodicalId":18110,"journal":{"name":"Liquid Crystals Today","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2020-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/1358314x.2020.1855919","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47876716","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 : 2020-04-02DOI: 10.1080/1358314x.2020.1819613
E. Anoardo, R. Rodríguez, A. M. F. Neto
Daniel Pusiol (1953–2019) was born in Santiago Temple, a small village located in the Province of Cordoba, Argentina. He studied physics in the city of Cordoba, at FaMAF, National University of Cor...
Daniel Pusiol(1953-2019)出生在阿根廷科尔多瓦省的一个小村庄Santiago Temple。他在科尔多瓦的FaMAF，国立科尔多瓦大学学习物理。
{"title":"The liquid crystal community loses an active member Professor Daniel Pusiol","authors":"E. Anoardo, R. Rodríguez, A. M. F. Neto","doi":"10.1080/1358314x.2020.1819613","DOIUrl":"https://doi.org/10.1080/1358314x.2020.1819613","url":null,"abstract":"Daniel Pusiol (1953–2019) was born in Santiago Temple, a small village located in the Province of Cordoba, Argentina. He studied physics in the city of Cordoba, at FaMAF, National University of Cor...","PeriodicalId":18110,"journal":{"name":"Liquid Crystals Today","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2020-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/1358314x.2020.1819613","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46057206","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 : 2020-04-02DOI: 10.1080/1358314x.2020.1819624
Karthik Nayani, Yu Yang, Huaizhe Yu, Purvil Jani, M. Mavrikakis, N. Abbott
ABSTRACT The societal impact of liquid crystals (LCs) in electrooptical displays arrived after decades of research involving molecular-level design of LCs and their alignment layers, and elucidation of LC electrooptical phenomena at device scales. The anisotropic optical, mechanical and dielectric properties of LCs used in displays also make LCs remarkable amplifiers of their interactions with chemical and biological species, thus opening up the possibility that LCs may play an influential role in a data-driven society that depends on information coming from sensors. In this article, we describe ongoing efforts to design LC systems tailored for chemical and biological sensing, efforts that mirror the challenges and opportunities in LC design and alignment tackled several decades ago during development of LC electrooptical displays. Now, however, traditional design approaches based on structure–property relationships are being supplemented by data-driven methods such as machine learning. Recent studies also show that computational chemistry can greatly increase the rate of discovery of chemically responsive LC systems. Additionally, non-equilibrium states of LCs are being revealed to be useful for design of biological sensors and more complex autonomous systems that integrate self-regulated actuation along with sensing. These topics and others are addressed in this article with the aim of highlighting approaches and goals for future research that will realise the full potential of LC-based sensors.
{"title":"Areas of opportunity related to design of chemical and biological sensors based on liquid crystals","authors":"Karthik Nayani, Yu Yang, Huaizhe Yu, Purvil Jani, M. Mavrikakis, N. Abbott","doi":"10.1080/1358314x.2020.1819624","DOIUrl":"https://doi.org/10.1080/1358314x.2020.1819624","url":null,"abstract":"ABSTRACT The societal impact of liquid crystals (LCs) in electrooptical displays arrived after decades of research involving molecular-level design of LCs and their alignment layers, and elucidation of LC electrooptical phenomena at device scales. The anisotropic optical, mechanical and dielectric properties of LCs used in displays also make LCs remarkable amplifiers of their interactions with chemical and biological species, thus opening up the possibility that LCs may play an influential role in a data-driven society that depends on information coming from sensors. In this article, we describe ongoing efforts to design LC systems tailored for chemical and biological sensing, efforts that mirror the challenges and opportunities in LC design and alignment tackled several decades ago during development of LC electrooptical displays. Now, however, traditional design approaches based on structure–property relationships are being supplemented by data-driven methods such as machine learning. Recent studies also show that computational chemistry can greatly increase the rate of discovery of chemically responsive LC systems. Additionally, non-equilibrium states of LCs are being revealed to be useful for design of biological sensors and more complex autonomous systems that integrate self-regulated actuation along with sensing. These topics and others are addressed in this article with the aim of highlighting approaches and goals for future research that will realise the full potential of LC-based sensors.","PeriodicalId":18110,"journal":{"name":"Liquid Crystals Today","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2020-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/1358314x.2020.1819624","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48744174","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 : 2020-01-02DOI: 10.1080/1358314X.2020.1771843
D. Broer
The International Liquid Crystal Elastomer Conference was this year organised in Eindhoven, The Netherlands. The organisers were Danqing Liu, Albert Schenning and Dick Broer from Eindhoven University of Technology. As location they chose the NatLab building in Eindhoven, which was the original building of Philips Research Laboratories, founded in 1914 by Gilles Holst who was the inventor of the low-pressure sodium lamp. It was also the origin of many important new products and technologies such as digital optical data storage (CD, DVD), the magnetics cassette tape and the IC LOCOS technology. But also a few of the earliest reactive mesogens, as basis for the Liquid Crystal Elastomer (LCE) and Network (LCN) technologies, were developed at Philips Research in the mid ‘80ties. Many of these LC molecules were brought on the screen by numerous presenters during the conference. It was the tenth time the ILCEC was organised and the world’s interest in this exiting class of liquid crystals is still growing. The number of participants this year was 120 (Figure 1) with chemists, physicists, engineers and representatives from industry who shared their fundamental advances and discussed their promising application opportunities. Especially meant for newcomers in the field, but also well appreciated by the more senior scientists, the meeting was preceded by a tutorial session, where experienced scientists like Prof. Peter Palffy-Muhoray, Prof. Claudio Zannoni and Prof. Hong Yang addressed the basic principles of the field in a framework of the history of the topics of the conference. In addition, a representative of Wiley, Dr Jos Lenders, explained the optimum conditions to maximise publication successes. The following three days of the conference, introduced by a plenary lecture of Prof. Tomiki Ikeda, there was much emphasis on the mechanical responses of the LCEs and LCNs with sessions on soft robotics, responsive surfaces and actuators (Figure 2). And together with the theoretical support presented in a theory session it demonstrates the very fast developments in this relatively young area with many very promising new approaches initiated from the chemistry and applications coming from engineering, sometime even try to lap frog by allocating Pavlovian behaviour to the polymer networks. Promising for the future of LCEs and LCNs is also the participation of the many young faculty members and students and their active involvement in discussions and contributions to the oral and poster presentations. To be mentioned here is Morgan Barnes from Rice University who won the Best Student Lecture Award for her presentation on Reactive 3D printing of liquid crystal elastomers for non-linear actuation (Figure 3). And the Poster Award winners: Yuanyuan Zhan from Eindhoven University of Technology (second prize),
{"title":"International liquid crystal elastomer conference 2019","authors":"D. Broer","doi":"10.1080/1358314X.2020.1771843","DOIUrl":"https://doi.org/10.1080/1358314X.2020.1771843","url":null,"abstract":"The International Liquid Crystal Elastomer Conference was this year organised in Eindhoven, The Netherlands. The organisers were Danqing Liu, Albert Schenning and Dick Broer from Eindhoven University of Technology. As location they chose the NatLab building in Eindhoven, which was the original building of Philips Research Laboratories, founded in 1914 by Gilles Holst who was the inventor of the low-pressure sodium lamp. It was also the origin of many important new products and technologies such as digital optical data storage (CD, DVD), the magnetics cassette tape and the IC LOCOS technology. But also a few of the earliest reactive mesogens, as basis for the Liquid Crystal Elastomer (LCE) and Network (LCN) technologies, were developed at Philips Research in the mid ‘80ties. Many of these LC molecules were brought on the screen by numerous presenters during the conference. It was the tenth time the ILCEC was organised and the world’s interest in this exiting class of liquid crystals is still growing. The number of participants this year was 120 (Figure 1) with chemists, physicists, engineers and representatives from industry who shared their fundamental advances and discussed their promising application opportunities. Especially meant for newcomers in the field, but also well appreciated by the more senior scientists, the meeting was preceded by a tutorial session, where experienced scientists like Prof. Peter Palffy-Muhoray, Prof. Claudio Zannoni and Prof. Hong Yang addressed the basic principles of the field in a framework of the history of the topics of the conference. In addition, a representative of Wiley, Dr Jos Lenders, explained the optimum conditions to maximise publication successes. The following three days of the conference, introduced by a plenary lecture of Prof. Tomiki Ikeda, there was much emphasis on the mechanical responses of the LCEs and LCNs with sessions on soft robotics, responsive surfaces and actuators (Figure 2). And together with the theoretical support presented in a theory session it demonstrates the very fast developments in this relatively young area with many very promising new approaches initiated from the chemistry and applications coming from engineering, sometime even try to lap frog by allocating Pavlovian behaviour to the polymer networks. Promising for the future of LCEs and LCNs is also the participation of the many young faculty members and students and their active involvement in discussions and contributions to the oral and poster presentations. To be mentioned here is Morgan Barnes from Rice University who won the Best Student Lecture Award for her presentation on Reactive 3D printing of liquid crystal elastomers for non-linear actuation (Figure 3). And the Poster Award winners: Yuanyuan Zhan from Eindhoven University of Technology (second prize),","PeriodicalId":18110,"journal":{"name":"Liquid Crystals Today","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2020-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/1358314X.2020.1771843","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41724214","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 : 2020-01-02DOI: 10.1080/1358314x.2020.1771844
I. Dierking
The main topic of this monograph is largely summarised by its subtitle. It discusses from both a theoretical, but much more so an experimental point of view the lubrication properties, friction and rheology of liquid crystal based systems and their applications from engineering to medicine. The book was published as part of the Springer Series in Materials Science (Vol 267) and is divided into five chapters. As common, chapter 1 provides the reader with an introduction to the liquid crystalline state of matter, distinguishing thermotropic and lyotropic systems, and generally introducing the different phases for calamitic and discotic mesogens. At this point it becomes apparent that the authors see liquid crystals as nanomaterials, hence the title of the book: Liquid-Crystal Nanomaterials. Personally, I find this somewhat misleading and quite irritating, because the community attaches a different meaning to the word nanomaterials than simply somewhat larger organic molecules. In the following the reader is taken through the optical properties, but not by introducing the birefringence of nematics, but rather straight away by discussing the phenomenon of selective reflection of cholesterics. The temperature dependence of the cholesteric pitch is then introduced, albeit with some very old, presumably hand drawn representations of measurements. The anisotropy of physical parameters such as the dielectric constants and the electro-optic Fredericks transition is then discussed under the heading of ‘Physical Anisotropy and Applications of Cholesteric liquid-crystal nanomaterials’, with the help of diagrams that are not particularly clear. When reading through the introductory chapter, one does not have the impression that much effort has been devoted to present a modern, up-to-date introduction into the field of liquid crystals. This is not helped by an apparent lack of language editing on the parts of Springer publishers. The introduction to tribology and lubrication of solids in Chapter 2 takes up much more space than that given to the structure and properties of liquid crystals in the first chapter. Modern antifriction additives are discussed for passive and active friction control, as are the effects of lubricant films on the friction of solids. This includes fine fluid layers on solid surfaces and their surface forces, boundary effects and hydrodynamic effects. An interesting and modern aspect in the form of medical applications is treated in some detail when discussing friction and lubrication in body joints. The chapter is well referenced, although again much of the mentioned literature is three or more decades old. With chapter 3 the text becomes quite a bit more technical and construction oriented as some of the measurement apparatus for experimental tests of liquid crystals seem to have been specifically constructed. The discussion firstly includes tribo-engineering tests. Standard equipment is described, as well as high-precision rheology, an
{"title":"Liquid-crystal nanomaterials: tribology and applications","authors":"I. Dierking","doi":"10.1080/1358314x.2020.1771844","DOIUrl":"https://doi.org/10.1080/1358314x.2020.1771844","url":null,"abstract":"The main topic of this monograph is largely summarised by its subtitle. It discusses from both a theoretical, but much more so an experimental point of view the lubrication properties, friction and rheology of liquid crystal based systems and their applications from engineering to medicine. The book was published as part of the Springer Series in Materials Science (Vol 267) and is divided into five chapters. As common, chapter 1 provides the reader with an introduction to the liquid crystalline state of matter, distinguishing thermotropic and lyotropic systems, and generally introducing the different phases for calamitic and discotic mesogens. At this point it becomes apparent that the authors see liquid crystals as nanomaterials, hence the title of the book: Liquid-Crystal Nanomaterials. Personally, I find this somewhat misleading and quite irritating, because the community attaches a different meaning to the word nanomaterials than simply somewhat larger organic molecules. In the following the reader is taken through the optical properties, but not by introducing the birefringence of nematics, but rather straight away by discussing the phenomenon of selective reflection of cholesterics. The temperature dependence of the cholesteric pitch is then introduced, albeit with some very old, presumably hand drawn representations of measurements. The anisotropy of physical parameters such as the dielectric constants and the electro-optic Fredericks transition is then discussed under the heading of ‘Physical Anisotropy and Applications of Cholesteric liquid-crystal nanomaterials’, with the help of diagrams that are not particularly clear. When reading through the introductory chapter, one does not have the impression that much effort has been devoted to present a modern, up-to-date introduction into the field of liquid crystals. This is not helped by an apparent lack of language editing on the parts of Springer publishers. The introduction to tribology and lubrication of solids in Chapter 2 takes up much more space than that given to the structure and properties of liquid crystals in the first chapter. Modern antifriction additives are discussed for passive and active friction control, as are the effects of lubricant films on the friction of solids. This includes fine fluid layers on solid surfaces and their surface forces, boundary effects and hydrodynamic effects. An interesting and modern aspect in the form of medical applications is treated in some detail when discussing friction and lubrication in body joints. The chapter is well referenced, although again much of the mentioned literature is three or more decades old. With chapter 3 the text becomes quite a bit more technical and construction oriented as some of the measurement apparatus for experimental tests of liquid crystals seem to have been specifically constructed. The discussion firstly includes tribo-engineering tests. Standard equipment is described, as well as high-precision rheology, an ","PeriodicalId":18110,"journal":{"name":"Liquid Crystals Today","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2020-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/1358314x.2020.1771844","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44593813","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 : 2020-01-02DOI: 10.1080/1358314X.2020.1771847
A. Draude
Active matter, in which local energy is converted into directed motion, is an area of strong interest in current soft matter research for potential applications in soft robotics. Living nematics are a category of active matter where nematic phases have active particles dispersed in them. In this paper, Turiv et al. study high and low concentrations of swimming bacteria in the nematic phase of the lyotropic chromonic liquid crystal DSCG via microscopy. Photo-alignment is used to create patterned director fields. Patterns including splay and bend are used to focus the trajectory of the bacteria and rectilinear jets undulate at high concentrations of bacteria. These jets are shown to be stabilised by the background director field and the experimental results are supported by simulations. In flows of either concentration of bacteria micro-spheres are shown to be transported along the pre-patterned flows.
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