Looping and cleavage of single DNA molecules by the two-site restriction endonuclease Sau3AI were measured with optical tweezers. A DNA template containing many recognition sites was used, permitting loop sizes from ~10 to 10,000 basepairs. At high enzyme concentration cleavage events were detected within 5 seconds and nearly all molecules were cleaved within 5 minutes. Activity decreased ~10-fold as the DNA tension was increased from 0.03 to 0.7 pN. Substituting Ca2+ for Mg2+ blocked cleavage, permitting measurement of stable loops. At low tension, the initial rates of cleavage and looping were similar (~0.025 s-1 at 0.1 pN), suggesting that looping is rate limiting. Short loops formed more rapidly than long loops. The optimum size decreased from ~250 to 45 bp and the average number of loops (in 1 minute) from 4.2 to 0.75 as tension was increased from 0.03 to 0.7 pN. No looping was detected at 5 pN. These findings are in qualitative agreement with recent theoretical predictions considering only DNA mechanics, but we observed weaker suppression with tension and smaller loop sizes. Our results suggest that the span and elasticity of the protein complex and protein-induced DNA bending and wrapping play an important role.
{"title":"DNA looping and cleavage by restriction enzymes studied by manipulation of single DNA molecules with optical tweezers","authors":"Douglas E. Smith, G. Gemmen, R. Millin","doi":"10.1117/12.681504","DOIUrl":"https://doi.org/10.1117/12.681504","url":null,"abstract":"Looping and cleavage of single DNA molecules by the two-site restriction endonuclease Sau3AI were measured with optical tweezers. A DNA template containing many recognition sites was used, permitting loop sizes from ~10 to 10,000 basepairs. At high enzyme concentration cleavage events were detected within 5 seconds and nearly all molecules were cleaved within 5 minutes. Activity decreased ~10-fold as the DNA tension was increased from 0.03 to 0.7 pN. Substituting Ca2+ for Mg2+ blocked cleavage, permitting measurement of stable loops. At low tension, the initial rates of cleavage and looping were similar (~0.025 s-1 at 0.1 pN), suggesting that looping is rate limiting. Short loops formed more rapidly than long loops. The optimum size decreased from ~250 to 45 bp and the average number of loops (in 1 minute) from 4.2 to 0.75 as tension was increased from 0.03 to 0.7 pN. No looping was detected at 5 pN. These findings are in qualitative agreement with recent theoretical predictions considering only DNA mechanics, but we observed weaker suppression with tension and smaller loop sizes. Our results suggest that the span and elasticity of the protein complex and protein-induced DNA bending and wrapping play an important role.","PeriodicalId":406438,"journal":{"name":"SPIE Optics + Photonics","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126205115","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}
Evolution is usually taught as the result of mutations and genetic recombinations combined with natural selection, but most living forms have symbiotic relationships with microorganisms, and in this sense symbiogenesis seems to play a very important role in the origin and life evolution. Symbiosis is an important support for the acquisition of new genomes and new metabolic capacities, which drives living forms' evolution. In this sense, the evolutionary changes can be explained by an integrated cooperation between organisms, in which symbiosis acts, not as an exception, but rather as the rule in nature. Beginning with the eukaryotic cell formation, symbiogenesis appears to be the main evolutionary mechanism in the establishment and maintenance of biomes, as well as the foundation of biodiversity, based on rather suddenly evolutionary novelty, which challenges the Darwinian gradualism. These principles can be applied to the life on Earth and beyond.
{"title":"The origins of life and the mechanisms of biological evolution","authors":"F. Carrapiço","doi":"10.1117/12.681946","DOIUrl":"https://doi.org/10.1117/12.681946","url":null,"abstract":"Evolution is usually taught as the result of mutations and genetic recombinations combined with natural selection, but most living forms have symbiotic relationships with microorganisms, and in this sense symbiogenesis seems to play a very important role in the origin and life evolution. Symbiosis is an important support for the acquisition of new genomes and new metabolic capacities, which drives living forms' evolution. In this sense, the evolutionary changes can be explained by an integrated cooperation between organisms, in which symbiosis acts, not as an exception, but rather as the rule in nature. Beginning with the eukaryotic cell formation, symbiogenesis appears to be the main evolutionary mechanism in the establishment and maintenance of biomes, as well as the foundation of biodiversity, based on rather suddenly evolutionary novelty, which challenges the Darwinian gradualism. These principles can be applied to the life on Earth and beyond.","PeriodicalId":406438,"journal":{"name":"SPIE Optics + Photonics","volume":"53 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134139122","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}
James Westphal, Antao Chen, Nathaniel Burt, Lih Y. Lin, L. Dalton, Jingdong Luo, A. Jen
Conjugated chromophores with permanent dipole moments can be aligned by heating a thin polymer film containing chromophores in an external electric field. The heated "guest-host" system is then cooled in the field to maintain the chromophores' alignment. Dielectric breakdown and charge transfer, however, often limit the external electric field to about 100 V/μm of film thickness. It was hypothesized that electrical pulses could increase the voltage of the poling field without damaging the sample films. This was achieved by combining an amplified waveform from a function generator with the DC poling field. Pulse amplitudes were varied from 10 to 103 V. Pulse frequencies were varied from 10-1 to 103 Hz with a duty cycle of up to 50% of the pulse period. Pulse amplitudes were found to have optimum effects at less than 15% of the DC field at low frequencies, 0.1-10 Hz, with a sinusoidal pulse shape. It was found that this technique induced up to a 20% improvement in optical properties without damaging the sample films.
{"title":"Pulse poling of high performance nonlinear chromophores in polymers","authors":"James Westphal, Antao Chen, Nathaniel Burt, Lih Y. Lin, L. Dalton, Jingdong Luo, A. Jen","doi":"10.1117/12.698378","DOIUrl":"https://doi.org/10.1117/12.698378","url":null,"abstract":"Conjugated chromophores with permanent dipole moments can be aligned by heating a thin polymer film containing chromophores in an external electric field. The heated \"guest-host\" system is then cooled in the field to maintain the chromophores' alignment. Dielectric breakdown and charge transfer, however, often limit the external electric field to about 100 V/μm of film thickness. It was hypothesized that electrical pulses could increase the voltage of the poling field without damaging the sample films. This was achieved by combining an amplified waveform from a function generator with the DC poling field. Pulse amplitudes were varied from 10 to 103 V. Pulse frequencies were varied from 10-1 to 103 Hz with a duty cycle of up to 50% of the pulse period. Pulse amplitudes were found to have optimum effects at less than 15% of the DC field at low frequencies, 0.1-10 Hz, with a sinusoidal pulse shape. It was found that this technique induced up to a 20% improvement in optical properties without damaging the sample films.","PeriodicalId":406438,"journal":{"name":"SPIE Optics + Photonics","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126475096","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}
Amorphous and nanostructured SiO2:DR1 sol-gel films were prepared by dip-coating. X-ray diffraction studies were performed to determine the long-order structure obtained in the films. The optical absorption (AO) measurements were done in three different nanostructures of the SiO2 network: lamellar, hexagonal and mixed. The AO measurements and the second harmonic generation (SHG) intensity were carried out at different orientation steps of the chromophores embedded in the films. These chromophore orientation distributions were obtained by means of the corona technique, and they depend on the corona poling time. We physically model the optical absorption and the second harmonic generation experimental results as function of the corona poling time, employing only one fitting parameter related to the matrix-chromophore interactions. The physical model and the experimental results were in an excellent agreement. The experimental results fitted by the model are shown in plots of order parameter against corona poling time and SHG intensity against corona poling time. The lamellar structure provides a larger order parameter values than those obtained for the other structures. A minimum value for the order parameter was detected by means of the optical absorption measurements at short poling times. For the SHG measurements, four different chromophore concentrations were used. As the concentration increases the measured SHG intensity increases too, but the increment is limited by the electrostatic interactions among the chromophores, which is also considered in our model.
{"title":"Optical absorption and second harmonic generation in SiO2:DR1 sol-gel films as function of poling time","authors":"A. Franco, G. Valverde-Aguilar, J. García-Macedo","doi":"10.1117/12.681250","DOIUrl":"https://doi.org/10.1117/12.681250","url":null,"abstract":"Amorphous and nanostructured SiO2:DR1 sol-gel films were prepared by dip-coating. X-ray diffraction studies were performed to determine the long-order structure obtained in the films. The optical absorption (AO) measurements were done in three different nanostructures of the SiO2 network: lamellar, hexagonal and mixed. The AO measurements and the second harmonic generation (SHG) intensity were carried out at different orientation steps of the chromophores embedded in the films. These chromophore orientation distributions were obtained by means of the corona technique, and they depend on the corona poling time. We physically model the optical absorption and the second harmonic generation experimental results as function of the corona poling time, employing only one fitting parameter related to the matrix-chromophore interactions. The physical model and the experimental results were in an excellent agreement. The experimental results fitted by the model are shown in plots of order parameter against corona poling time and SHG intensity against corona poling time. The lamellar structure provides a larger order parameter values than those obtained for the other structures. A minimum value for the order parameter was detected by means of the optical absorption measurements at short poling times. For the SHG measurements, four different chromophore concentrations were used. As the concentration increases the measured SHG intensity increases too, but the increment is limited by the electrostatic interactions among the chromophores, which is also considered in our model.","PeriodicalId":406438,"journal":{"name":"SPIE Optics + Photonics","volume":"146 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128709767","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}
D. Barada, Hiroshi Sumimura, T. Fukuda, Jun Young Kim, M. Itoh, T. Yatagai
Theoretical models for photoinduced birefringence and chiral structure formation in achiral azobenzene-containing materials were proposed considering phototriggered molecular reorientation via trans-cis-trans photoisomerization cycles of azobenzene. The photoisomerization cycles were expressed by two rate equations of the orientation distributions of trans- and cis-forms. Phototriggered molecular reorientation by illuminating linearly polarized light was verified theoretically. The photoinduced helical structure formation was simualted by elliptically polarized light. The molecular rotation angle was dependent on the sign of the ellipticity. The time evolution of the helical structure formation was consistent with the experimental result that reported by other papers.
{"title":"Computer simulation of photoinduced helical structure formation on azobenzene-containing materials","authors":"D. Barada, Hiroshi Sumimura, T. Fukuda, Jun Young Kim, M. Itoh, T. Yatagai","doi":"10.1117/12.683790","DOIUrl":"https://doi.org/10.1117/12.683790","url":null,"abstract":"Theoretical models for photoinduced birefringence and chiral structure formation in achiral azobenzene-containing materials were proposed considering phototriggered molecular reorientation via trans-cis-trans photoisomerization cycles of azobenzene. The photoisomerization cycles were expressed by two rate equations of the orientation distributions of trans- and cis-forms. Phototriggered molecular reorientation by illuminating linearly polarized light was verified theoretically. The photoinduced helical structure formation was simualted by elliptically polarized light. The molecular rotation angle was dependent on the sign of the ellipticity. The time evolution of the helical structure formation was consistent with the experimental result that reported by other papers.","PeriodicalId":406438,"journal":{"name":"SPIE Optics + Photonics","volume":"118 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132621678","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}
Hot electron injection from the excited electronic singlet state of perylene chromophores into the (110) surface of rutile TiO2 single crystals was measured with femtosecond two-photon photoemission (2PPE) for different anchor/bridge groups attached to the perylene chromophore. Femtosecond 2PPE probes the time and energy dependence of the population of firstly the excited state of the chromophore and secondly of the hot electrons injected into the surface layer of the semiconductor. Measuring both these contributions gives a complete picture of the ultrafast photo-induced injection process and bridges the gap to conventional measurements of the rise time of the corresponding photocurrent. Studying the system in ultra-high-vacuum (UHV) makes all the tools of surface science available. Impurities on the surface were studied with XPS, the alignment of the occupied and unoccupied electronic levels at the interface with UPS and with 2PPE, respectively. The orientation of the elongated chromophores with respect to the crystal surface was deduced from angle and polarization dependent 2PPE signals making use of the known orientation of the dipole moment for the optical transition, the energy distribution of the injected hot electrons was determined with 2PPE from the energy distribution of the photoemitted electrons, and finally the escape of the injected electrons from the surface to bulk states of the semiconductor was obtained from femtosecond 2PPE transients.
{"title":"Dynamics of electron injection from the excited state of anchored organic molecules into rutile (110)TiO2","authors":"L. Gundlach, R. Ernstorfer, F. Willig","doi":"10.1117/12.683719","DOIUrl":"https://doi.org/10.1117/12.683719","url":null,"abstract":"Hot electron injection from the excited electronic singlet state of perylene chromophores into the (110) surface of rutile TiO2 single crystals was measured with femtosecond two-photon photoemission (2PPE) for different anchor/bridge groups attached to the perylene chromophore. Femtosecond 2PPE probes the time and energy dependence of the population of firstly the excited state of the chromophore and secondly of the hot electrons injected into the surface layer of the semiconductor. Measuring both these contributions gives a complete picture of the ultrafast photo-induced injection process and bridges the gap to conventional measurements of the rise time of the corresponding photocurrent. Studying the system in ultra-high-vacuum (UHV) makes all the tools of surface science available. Impurities on the surface were studied with XPS, the alignment of the occupied and unoccupied electronic levels at the interface with UPS and with 2PPE, respectively. The orientation of the elongated chromophores with respect to the crystal surface was deduced from angle and polarization dependent 2PPE signals making use of the known orientation of the dipole moment for the optical transition, the energy distribution of the injected hot electrons was determined with 2PPE from the energy distribution of the photoemitted electrons, and finally the escape of the injected electrons from the surface to bulk states of the semiconductor was obtained from femtosecond 2PPE transients.","PeriodicalId":406438,"journal":{"name":"SPIE Optics + Photonics","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133642816","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}
We describe a computer application designed to analyze hyperspectral data collected by the Compact Infrared Spectrometer for Mars (CRISM). The application links the spectral, imaging and mapping perspectives on the eventual CRISM dataset by presenting the user with three different ways to analyze the data. One of the goals when developing this instrument is to build in the latest algorithms for detection of spectrally compelling targets on the surface of the Red Planet, so they may be available to the Planetary Science community without cost and with a minimal learning barrier to cross. This will allow the Astrobiology community to look for targets of interest such as hydrothermal minerals, sulfate minerals and hydrous minerals and be able to map the extent of these minerals using the most up-to-date and effective algorithms. The application is programmed in Java and will be made available for Windows, Mac and Linux platforms. Users will be able to embed Groovy scripts into the program in order to extend its functionality. The first collection of CRISM data will occur in September of 2006 and this data will be made publicly available six months later via the Planetary Datasystem (PDS). Potential users in the community should therefore look forward to a release date mid-2007. Although exploration of the CRISM data set is the motivating force for developing these software tools, the ease of writing additional Groovy scripts to access other data sets makes the tools useful for mineral exploration, crop management, and characterization of extreme environments here on Earth or other terrestrial planets. The system can be easily implemented for use by high school, college, and graduate level students.
{"title":"MR PRISM: a spectral analysis tool for the PRISM","authors":"A. Brown, M. Storrie-Lombardi","doi":"10.1117/12.677107","DOIUrl":"https://doi.org/10.1117/12.677107","url":null,"abstract":"We describe a computer application designed to analyze hyperspectral data collected by the Compact Infrared Spectrometer for Mars (CRISM). The application links the spectral, imaging and mapping perspectives on the eventual CRISM dataset by presenting the user with three different ways to analyze the data. One of the goals when developing this instrument is to build in the latest algorithms for detection of spectrally compelling targets on the surface of the Red Planet, so they may be available to the Planetary Science community without cost and with a minimal learning barrier to cross. This will allow the Astrobiology community to look for targets of interest such as hydrothermal minerals, sulfate minerals and hydrous minerals and be able to map the extent of these minerals using the most up-to-date and effective algorithms. The application is programmed in Java and will be made available for Windows, Mac and Linux platforms. Users will be able to embed Groovy scripts into the program in order to extend its functionality. The first collection of CRISM data will occur in September of 2006 and this data will be made publicly available six months later via the Planetary Datasystem (PDS). Potential users in the community should therefore look forward to a release date mid-2007. Although exploration of the CRISM data set is the motivating force for developing these software tools, the ease of writing additional Groovy scripts to access other data sets makes the tools useful for mineral exploration, crop management, and characterization of extreme environments here on Earth or other terrestrial planets. The system can be easily implemented for use by high school, college, and graduate level students.","PeriodicalId":406438,"journal":{"name":"SPIE Optics + Photonics","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116498541","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}
Models of the index response of diffusion photopolymers typically assume that polymerization is proportional to optical intensity. However, common radical initiators self-terminate. This reduces the polymerization rate and has been shown in steady state to result in polymerization that is proportional to the square root of intensity. We examine the impact of sublinear polymerization rate on the spatial distribution of index in volume photopolymers. In contrast to previous work based on spatial frequency harmonics, we consider a Gaussian focus and examine the index in the spatial domain. This can thus be thought of as the impulse response of the material which, due to the nonlinear response, is not the Fourier transform of the previous studies. We show that sublinear polymerization rate dramatically impacts the spatial confinement of the index response. A case of particular interest to applications such as shift-multiplexed holography is a Gaussian beam translated orthogonal to its axis. In this geometry, a square-root material response yields an index profile of infinite axial dimension. We verify this prediction experimentally. The axial confinement of cationic (linear) photopolymer is shown to be significantly smaller than a radical (sublinear) photopolymer under the same writing conditions, confirming the prediction.
{"title":"Impact of initiation species on index distribution in diffusion photopolymers","authors":"A. Sullivan, Matthew W. Grabowski, R. McLeod","doi":"10.1117/12.679853","DOIUrl":"https://doi.org/10.1117/12.679853","url":null,"abstract":"Models of the index response of diffusion photopolymers typically assume that polymerization is proportional to optical intensity. However, common radical initiators self-terminate. This reduces the polymerization rate and has been shown in steady state to result in polymerization that is proportional to the square root of intensity. We examine the impact of sublinear polymerization rate on the spatial distribution of index in volume photopolymers. In contrast to previous work based on spatial frequency harmonics, we consider a Gaussian focus and examine the index in the spatial domain. This can thus be thought of as the impulse response of the material which, due to the nonlinear response, is not the Fourier transform of the previous studies. We show that sublinear polymerization rate dramatically impacts the spatial confinement of the index response. A case of particular interest to applications such as shift-multiplexed holography is a Gaussian beam translated orthogonal to its axis. In this geometry, a square-root material response yields an index profile of infinite axial dimension. We verify this prediction experimentally. The axial confinement of cationic (linear) photopolymer is shown to be significantly smaller than a radical (sublinear) photopolymer under the same writing conditions, confirming the prediction.","PeriodicalId":406438,"journal":{"name":"SPIE Optics + Photonics","volume":"21 3","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"113943808","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}
We have invented a novel all-optical-logic microfluidic system which is automatically controlled only by visible or near infrared light with down to submilliwatt power. No electric power supply, no external or MEMS pump, no tubings or connectors, no microfluidic valves, nor surface patterning are required in our system. Our device only consists of a single-layer PDMS microfluidic chip and newly invented photoactive nanoparticles. Our photoactive nanoparticles are capable of converting optical energy to hydrodynamic energy in fluids. The nanoparticle themselves are biocompatible and can be biofunctionalized. Via these photoactive nanoparticles, we used only light to drive, guide, switch and mix liquid in optofluidic logic circuits with desired speeds and directions. We demonstrated the optofluidic controls in transportation of biomolecules and cells.
{"title":"All-optical microfluidic circuit for biochemical and cellular analysis powered by photoactive nanoparticles","authors":"G. Liu, Jaeyoun Kim, Luke P. Lee","doi":"10.1117/12.682540","DOIUrl":"https://doi.org/10.1117/12.682540","url":null,"abstract":"We have invented a novel all-optical-logic microfluidic system which is automatically controlled only by visible or near infrared light with down to submilliwatt power. No electric power supply, no external or MEMS pump, no tubings or connectors, no microfluidic valves, nor surface patterning are required in our system. Our device only consists of a single-layer PDMS microfluidic chip and newly invented photoactive nanoparticles. Our photoactive nanoparticles are capable of converting optical energy to hydrodynamic energy in fluids. The nanoparticle themselves are biocompatible and can be biofunctionalized. Via these photoactive nanoparticles, we used only light to drive, guide, switch and mix liquid in optofluidic logic circuits with desired speeds and directions. We demonstrated the optofluidic controls in transportation of biomolecules and cells.","PeriodicalId":406438,"journal":{"name":"SPIE Optics + Photonics","volume":"96 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129867303","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}
The chromophoric materials were prepared by copolymerization of various methacrylic monomers. The incorporation of the chromophore groups was done by coupling reaction of diazonium salts of the sulfonamide such as: sulfomethazine or sulfisomidine). The copolymers having free OH groups were able to react with 3-triethoxypropyl isocyanate forming intermediates used to prepare hybrid transparent films by sol-gel technique. The films of both copolymers as well as of hybrid sol-gel structures showed photochromic properties via trans-cis isomerization of the diazo groups. The absorption maximum of the trans form was ca. 435-445 nm depending on chemical composition of the material. Illumination of the films with coherent laser beams (two-beam coupling) resulted in formation of diffraction grating. The diffraction efficiency reached 4-5 % and refractive index modulation was in the range up to 0.0032.
{"title":"Polymer modified sol-gel materials for photochromic applications","authors":"R. Janik, S. Kucharski","doi":"10.1117/12.680055","DOIUrl":"https://doi.org/10.1117/12.680055","url":null,"abstract":"The chromophoric materials were prepared by copolymerization of various methacrylic monomers. The incorporation of the chromophore groups was done by coupling reaction of diazonium salts of the sulfonamide such as: sulfomethazine or sulfisomidine). The copolymers having free OH groups were able to react with 3-triethoxypropyl isocyanate forming intermediates used to prepare hybrid transparent films by sol-gel technique. The films of both copolymers as well as of hybrid sol-gel structures showed photochromic properties via trans-cis isomerization of the diazo groups. The absorption maximum of the trans form was ca. 435-445 nm depending on chemical composition of the material. Illumination of the films with coherent laser beams (two-beam coupling) resulted in formation of diffraction grating. The diffraction efficiency reached 4-5 % and refractive index modulation was in the range up to 0.0032.","PeriodicalId":406438,"journal":{"name":"SPIE Optics + Photonics","volume":"67 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126214468","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}
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