Catálogo de publicaciones - libros

Future biomimetic systems, developed either for nanobiotechnology or nanotechnology, could include protein(s) in its assembly, formation, and, perhaps, in its final structure as an integral component leading to specific and controllable functions. In the new field of molecular biomimetics, a true marriage of traditional physical and biological fields, hybrid materials could potentially be assembled from the molecular level using the recognition and assembly properties of proteins that specifically bind to inorganics [ 1 ]. Molecular biomimetics offers three simultaneous solutions to the problem of the control and fabrication of large-scale nanostructures and ordered assemblies of materials in two- and three-dimensions. The first is that inorganic-binding peptides and proteins are selected and designed at the molecular level and through genetics. This allows control at the lowest dimensional scale possible. The second is that such proteins can be used as linkers or molecular erector sets to join synthetic entities, including nanoparticles, functional polymers, or other nanostructures on molecular templates. Finally, the third solution is that the biological molecules self- and co-assemble into ordered nano-structures. This ensures a robust assembly process for the construction of complex nano-, and possibly hierarchical-structures, similar to those found in nature.

Most of the present micro/nano biodevices are designed for a single use, as opposed to ‘classical’ non-biodevices (e.g., from the steam engine to the microchip). Once their function, be that simple molecular recognition like in microarrays or even biomolecular computation as in DNA computation arrays, is fulfilled and the information is passed further to signal and information processing systems, the product becomes functionally obsolete. There are indeed a few notable exceptions, e.g., biosensors and charge-controlled DNA hybridization arrays, but even these function for a limited period of time. This one-use character of micro/nano-biodevices is more an expression of the lack of robustness of their components (e.g., proteins, cells) rather than one of economic sense. Moreover, in advanced biodevices the biomolecular recognition will help to achieve their function, rather than being their function, whichwould allowthese devices to have a continuous instead of one-off mode of operation.

In the early 21^st century, nanotechnology is a field in rapid flux and development, and definition of its boundaries can be elusive. Aspects of multiple disciplines, ranging from physics to computer science to biotechnology, legitimately contribute to the endeavor. This breadth of field allows many interested parties to contribute to nanotechnology, but the same ambiguity can effectively render the field indistinct. The precise definition of nanotechnology remains debatable, so consideration of the present scope of the field may be useful.

Biomolecular transport devices are now being used for drug development and delivery, single molecule manipulation, detection and transport and rapid molecular analysis. Many of these processes are illustrated by natural ion channels which are ion-selective nanoscale conduits in the body which allow nutrients in and waste products out. In this chapter we review the state of the art of modeling and computation of biomolecular transport in what we term synthetic ion nanochannels consisting of rectangular silicon channels for which the walls are negatively charged; we also consider the case where the walls are not charged.We consider computational techniques ranging from continuum models utilizing the Poisson- Nernst-Planck system to molecular dynamic simulations that allow tracking of individual molecules. Biomolecular transport can be modeled by incorporating hindered diffusion concepts and the methods are employed to predict the transport of albumin and glucose in silicon nanochannels. Brownian Dynamics and Molecular Dynamics methods represent techniques that must be used when continuum methods break down and these methods are also reviewed. It should be noted that the exact boundary between continuum methods and molecular simulation methods is not always clear.

Although the clinical arsenal in treating cancer has been greatly extended in recent years with the application of new drugs and therapeutic modalities, the three basic approaches continue to be (in order of success) surgical resection, radiation, and chemotherapy. The latter treatment modality is primarily directed at metastatic cancer, which generally has a poor prognosis. A significant proportion of research investment is focused on improving the efficacy of chemotherapy, which is often the only hope in treating a cancer patient. Yet the challenges with chemotherapy are many. They include drug resistance by tumor cells, toxic effects on healthy tissue, inadequate targeting, and impaired transport to the tumor. Determination of proper drug dosage and scheduling, and optimal drug concentration can also be difficult. Finally, drug release kinetics at the tumor site is an important aspect of chemotherapy.

Nanotechnology is an emerging field that has been embraced by those in clinical medicine. The most novel aspect of nanotechnology is the ability to precisely fabricate devices on a physical scale heretofore only realized in science fiction. Most notable medical applications have involved micro-sized devices with integrated micro- and/or nano-scale features used for controlled drug delivery or biomolecular analysis. BioMEMS (Biological Micro-Electro-Mechanical Systems) devices have served as conduits for nanotechnology to enter clinical medicine. However, new theoretical applications will further assert nanotechnology as a multifaceted biomedical discipline.