Introduction

Artificial living technologies are rapidly developing in several laboratories around the world: in USA (Steen Rasmussen, James Bailey, Hans Ziock, Los Alamos National Laboratory (LANL [1]); Liaohai Chen, Argone National Laboratory), in Italy (Pier Luigi Luisi's group at RomaTre University), in Germany (John S. McCaskill, Guenter von Kiedrowski, Ruhr-Universitaet Bochum; Patrick Wagler, Protostreem GmbH), and in European Center for Living Technology (headquarter in Venice). New creating nano biorobots are planed to be used for nanomedicine, nanoecology, and for future emerging new information technologies. Despite of really useful benefits of these artificial living technologies one can foresee also some possible dangerous events in the case if these new creating artificial living cells might self-mutate and escape to the natural biospheres. Vilnius University research group is creating molecular electronics logic gates regulating the photosynthesis, growing and dividing of artificial living cells and nanobiorobots in the order to prevent the negative affects of these new emerging artificial living information technologies. The molecular electronics and spintronics logical devices which regulate photosynthesis, self-assembling to the mobile computing structures, selectively capturing and transporting nuclear, chemical and microbial pollutions already were quantum mechanically designed in our previous research [2].

The artificial minimal living cells (LANL scientists call them as protocells) that are synthesized in USA Los Alamos National Laboratory (LANL) [1] are only a few (4-6) nanometers in size. In their simplest form, these cells consist of a micelle which acts as the container, a light driven metabolism, and a genetic system, whose functions are all very tightly coupled. The container consists of amphiphilic fatty acid (FA) molecules that self-assemble into a micelle. The hydrophobic interior of the micelle provides an alternative thermodynamic environment from the aqueous or methanol  exterior and acts as a sticking point for the photosensitizer, fatty acid precursors (pFA) (food), and the genetic material. Peptide nucleic acid (PNA) is chosen as the genetic material as it is far less polar than RNA or DNA and therefore should stick to the micelle, especially if hydrophobic chains are added to the PNA backbone. It is also capable of undergoing the same Watson-Crick pairing and replication as RNA and DNA. PNA is similar to DNA but has a peptide-based backbone, as opposed to DNA's sugar-phosphate backbone.

The first main goal of this research is to report the results of quantum mechanical (QM) modeling of the self-assembly and charge transfer in a minimal protocell [1] that might have implications for the first living organism on the Earth arround 3.8-3.5 bilion years ago. The climate in the Earth at that time was hot with intense UV radiation therefore PNAs might were the most suitable for genome of minimal living cells in comparison with RNA or DNA. This article uses a collection of quantum mechanical tools and applies them to a variety of protocell photosynthetic problems, while also providing a perspective of the requirements for success in the synthesis of new forms of living organisms.

The metabolism involves the photoexcitation of an electron in various photosensitizers which are stabilized by the donation of an electron from non-canonical PNA bases (for example, 8-oxo-guanine). The excited electron is in turn used to cleave a fatty acid precursor  to yield another fatty acid molecule, thereby allowing the container to grow until it reaches an unstable size and divides. The artificial minimal cell could be fed PNA monomers or use an essentially identical metabolism to convert a PNA precursor monomer into a true monomer, thereby also providing the material to allow the double-stranded PNA "gene" to replicate when it undergoes a random dehybridization to yield two complementary single-stranded templates [1]. Finally, as the different nucleobases have different electron donor and electron relay capabilities, there is also a mechanism for natural selection, with some bases and base orderings being superior to others in their ability to facilitate the metabolism.

The artificial minimal living cell contains on the order of 103 atoms. Due to its small size, all its processes, including its self-assembly from component molecules, its absorption of light, and its metabolism should in principle be investigated using quantum mechanical (wave) theory.

Usually self-reproducing artificial living cells that are creating in LANL and in other laboratories do not have the nanosize electronics tools which might be able to regulate the growth and multiplication. It is important to have possibility to stimulate or prevent uncontrolled multiplication of artificial living organisms by installing different molecular electronics devices. The second main goal of this research is by using quantum mechanical experiments to predict the possibility of biochemical experimental synthesis of molecular electronics controlled artificial minimal living cells or nanobiorobots which might be used for nanomedicine and nanoecology. It is presented in this research the quantum mechanically designed molecular electronics OR logical gate for the the regulation of artificial minimal living cell functions.

[1] S. Rasmussen, L. Chen, M. Nilsson, and S. Abe, Artificial Life, vol 9, 267-316 (2003).
[2] A. Tamulis, J. Tamuliene, V. Tamulis, "Quantum Mechanical Design of Photoactive Molecular Machines and Logical Devices", in "Handbook of Photochemistry and Photobiology", Vol. 3 "Supramolecular Photochemistry", Ed. H.S. Nalwa, American Scientific Publishers, 495-553, 2003.