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Photonic-plasmonic microcavity for ultrasensitive protein detection
WGM sensors derive their unprecedented sensitivity from the use of high quality-factor (Q-factor) optical resonances to monitor wavelength shift signals upon binding of biomolecules or nanobeads to the resonator surface. Even a single virus could be detected. Yet, if e.g. a single protein molecule shall be detected, the sensitivity has to be boosted.
There have been several approaches, such as the generation of hot spots using a hybrid photonic-plasmonic sensing concept with a gold nanoparticle (NP) layer coupled to a WGM biosensor.
However, there are some drawbacks: First, measurements cannot be done directly in solution. Second, real-time analysis is not possible since the proteins have to be pre-adsorbed on the NPs. Third, proteins are adsorbed randomly within the NP layer – outside of plasmonic field enhancements sites – which lowers the detection sensitivity. A German-American team led by Frank Vollmer and Melik C. Demirel now proposes an alternative concept overcoming these problems: optical trapping of protein molecules at the sites of plasmonic field enhancements in a random gold NP layer.
The stable integration of the microsphere WGM biosensor with a wetted gold NP layer is critical for achieving ultra-sensitive detection. Therefore, the silica microsphere cavity remains fixed on the Au NP layer. The Q-factor of the microsphere drops slightly but is still in the 105 range. After adding bovine serum albumin (BSA) solution at microliter of sample volumes, which enters the NP layer by capillary suction, the researchers observed an unexpectedly large significant wavelength shift.
The achieved sensitivity in the order of femtomole concentration levels was very surprising, and cannot be explained from random binding of the BSA molecules to the NP surface. Instead, the scientists hypothesized that the protein molecules prefer to bind to hotspot locations (i.e. closely spaced random NPs) of plasmon resonances excited in the NP layer due to optical trapping. To validate this hypothesis, they calculated the electromagnetic field distribution in a model NP layer using generalized Mie theory and simulated the expected wavelength shift due to the binding of proteins. Their calculations showed that, indeed, optical trapping of the proteins at highly sensitive plasmonic hotspot locations is essential for achieving high sensitivity in microcavity biosensing.
The achieved sensitivity in the order of femtomole concentration levels was very surprising, and cannot be explained from random binding of the BSA molecules to the NP surface.
Instead, the scientists hypothesized that the protein molecules prefer to bind to hotspot locations (i.e. closely spaced random NPs) of plasmon resonances excited in the NP layer due to optical trapping. To validate this hypothesis, they calculated the electromagnetic field distribution in a model NP layer using generalized Mie theory and simulated the expected wavelength shift due to the binding of proteins.
Their calculations showed that, indeed, optical trapping of the proteins at highly sensitive plasmonic hotspot locations is essential for achieving high sensitivity in microcavity biosensing.
The Team, consisting of scientists at the Pennsylvania State University (USA), at BASF SE (Ludwigshafen, Germany), the Massachusetts Institute of Technology (Cambridge, USA), and the Max Planck Institute for the Science of Light (Erlangen, Germany), has established a new promising route towards single molecule resolution in WGM biosensors coupled to engineered or random plasmonic nanoantennas.
Using a random NP layer has the advantage of integration to a microfluidic device, and gold NPs can be easily functionalized with recognition elements such as oligonucleotides or proteins. The approach could be of interest for many areas including medical biosensing and drug screening.
Source: http://phys.org/news/2012-08-photonic-plasmonic-microcavity-ultrasensitive-protein.html
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Founded by Russian entrepreneur Dmitry Itskov in February 2011 with the participation of leading Russian specialists in the field of neural interfaces, robotics, artificial organs and systems.
The main goals of the 2045 Initiative: the creation and realization of a new strategy for the development of humanity which meets global civilization challenges; the creation of optimale conditions promoting the spiritual enlightenment of humanity; and the realization of a new futuristic reality based on 5 principles: high spirituality, high culture, high ethics, high science and high technologies.
The main science mega-project of the 2045 Initiative aims to create technologies enabling the transfer of a individual’s personality to a more advanced non-biological carrier, and extending life, including to the point of immortality. We devote particular attention to enabling the fullest possible dialogue between the world’s major spiritual traditions, science and society.
A large-scale transformation of humanity, comparable to some of the major spiritual and sci-tech revolutions in history, will require a new strategy. We believe this to be necessary to overcome existing crises, which threaten our planetary habitat and the continued existence of humanity as a species. With the 2045 Initiative, we hope to realize a new strategy for humanity's development, and in so doing, create a more productive, fulfilling, and satisfying future.
The "2045" team is working towards creating an international research center where leading scientists will be engaged in research and development in the fields of anthropomorphic robotics, living systems modeling and brain and consciousness modeling with the goal of transferring one’s individual consciousness to an artificial carrier and achieving cybernetic immortality.
An annual congress "The Global Future 2045" is organized by the Initiative to give platform for discussing mankind's evolutionary strategy based on technologies of cybernetic immortality as well as the possible impact of such technologies on global society, politics and economies of the future.
Future prospects of "2045" Initiative for society
2015-2020
The emergence and widespread use of affordable android "avatars" controlled by a "brain-computer" interface. Coupled with related technologies “avatars’ will give people a number of new features: ability to work in dangerous environments, perform rescue operations, travel in extreme situations etc.
Avatar components will be used in medicine for the rehabilitation of fully or partially disabled patients giving them prosthetic limbs or recover lost senses.
2020-2025
Creation of an autonomous life-support system for the human brain linked to a robot, ‘avatar’, will save people whose body is completely worn out or irreversibly damaged. Any patient with an intact brain will be able to return to a fully functioning bodily life. Such technologies will greatly enlarge the possibility of hybrid bio-electronic devices, thus creating a new IT revolution and will make all kinds of superimpositions of electronic and biological systems possible.
2030-2035
Creation of a computer model of the brain and human consciousness with the subsequent development of means to transfer individual consciousness onto an artificial carrier. This development will profoundly change the world, it will not only give everyone the possibility of cybernetic immortality but will also create a friendly artificial intelligence, expand human capabilities and provide opportunities for ordinary people to restore or modify their own brain multiple times. The final result at this stage can be a real revolution in the understanding of human nature that will completely change the human and technical prospects for humanity.
2045
This is the time when substance-independent minds will receive new bodies with capacities far exceeding those of ordinary humans. A new era for humanity will arrive! Changes will occur in all spheres of human activity – energy generation, transportation, politics, medicine, psychology, sciences, and so on.
Today it is hard to imagine a future when bodies consisting of nanorobots will become affordable and capable of taking any form. It is also hard to imagine body holograms featuring controlled matter. One thing is clear however: humanity, for the first time in its history, will make a fully managed evolutionary transition and eventually become a new species. Moreover, prerequisites for a large-scale expansion into outer space will be created as well.
Key elements of the project in the future
• International social movement
• social network immortal.me
• charitable foundation "Global Future 2045" (Foundation 2045)
• scientific research centre "Immortality"
• business incubator
• University of "Immortality"
• annual award for contribution to the realization of the project of "Immortality”.
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