Photo-Excitation in Nanosystems: Control, Dynamics and Kinetics

Regents Of The University Of Michigan - Ann Arbor, Ann Arbor MI

Investigators

Abstract

New nano-probes and nano-tools will be developed, using magnetic and stochastic control and modulation of photo-excited nano-particles. These consist of composite, heterogeneous and hybrid nanoparticles that contain a mix of organic and inorganic polymers and glasses, semi-conductors and metals, and are prepared by a combination of chemical and physical methods. Their optimization and miniaturization limits will be studied, as well as their use as nano-instruments for the study of physical and chemical dynamics. Specific examples are size-dependent viscosity measurements in complex fluids and chemical reaction kinetics in nano-bottles. The extension of optical trapping to nano-particles with sizes well below the optical diffraction limit will also be studied, as will its optimization by the use of complex nanoparticles made of composite materials. This will add the dimension of photonic control to the magnetic and stochastic control of the nano-tools and probes. A combination of such nano-systems will be utilized for basic studies on chemical reaction kinetics in nano-bottles, nano-pores and other nano-domains, where the lack of convection is expected to result in non-classical laws of reaction kinetics. These studies are aimed at advancing the theoretical understanding of reaction kinetics laws for small, confined domains. The intellectual challenges of the proposed project include the design and preparation methods required for the optimization and miniaturization of the complex nano-systems to be used as versatile tools. Similarly, the design of nano-reactor systems for the basic understanding of elementary reaction kinetics in nano-domains, as well as the selection and monitoring of elementary reactions to be studied under these constraints, present further intellectual challenge. On the other hand, the theoretical understanding of the non-classical reaction kinetics laws that are prevalent in nano-domains has wide implications and is needed for a better biochemical understanding of intracellular reactions and drug interventions, as well as for better control of etching reactions in nano-lithography. Also, the near-field interactions between photons and composite matter, all confined to sub-wavelength dimensions, are of both theoretical and practical interest, where the latter encompasses both in-vivo optical imaging and photodynamic therapy. Such composite nanoparticles, designed by the author's laboratory, have already been applied by Molecular Therapeutics, Inc. (Ann Arbor, MI) for in-vivo brain cancer (gliosarcoma) photodynamic therapy and, simultaneously, for contrast enhancement of the in-vivo MRI used for monitoring the above therapy. Future advances in the capabilities of such nanoplatforms are expected to lead to further and more advanced biomedical applications for nanotechnology and bio-nanotechnology, such as a rotating nanoparticle-based immunoassay method. The successful execution of such biomedical and technological advances will be significantly aided by solving the basic science challenges posed in this proposal. This project will also educate graduate and postdoctoral students in novel multidisciplinary aspects of nanoparticles and nano-systems subjects that are at the cutting edge of research and require acquiring expertise that stretches from physics to medicine. New nano-probes and nano-tools will be developed, using nano-particles. These consist of a mix of organic and inorganic polymers and glasses, semi-conductors and metals, and are prepared by a combination of chemical and physical methods. Their optimization and miniaturization limits will be studied, as well as their use as nano-instruments for the study of physical and chemical dynamics. A combination of such nano-systems will be utilized for basic studies on chemical reaction kinetics in nano-domains, where we expect new laws of reaction kinetics. These studies are needed for a better biochemical understanding of intracellular reactions and drug interventions, as well as for better control of etching reactions in nano-lithography (computer chip industry). Such composite nanoparticles, designed by the author's laboratory, have already been applied by Molecular Therapeutics, Inc. (Ann Arbor, MI) for in-vivo brain cancer (gliosarcoma) photodynamic therapy and, simultaneously, for contrast enhancement of the in-vivo MRI used for monitoring the above therapy. Future advances in the capabilities of such nanoplatforms are expected to lead to further and more advanced biomedical applications, such as a rotating nanoparticle-based immunoassay method. The successful execution of such biomedical and technological advances will be significantly aided by solving the basic science challenges posed in this proposal. This project will also educate graduate and postdoctoral students in novel multidisciplinary aspects of nanoparticles and nanosystems.