Posted: May 31, 2010

Molecular computations based on DNAzymes and their substrates

(Nanowerk News) New perspectives are opening up in bio-engineering thanks to research jointly carried out by teams of chemists at the University of Liège and the Hebrew University of Jerusalem within the framework of the European MOLOC project (Molecular Logic Circuits). This work has led to the publication of two important publications, one straight after the other, in the Nature Nanotechnology journal.
In the latest one, published on May 30 ("DNA computing circuits using libraries of DNAzyme subunits"), the researchers have theoretically developed and experimentally demonstrated that the artificial catalytic nucleic acids called DNAzymes and their substrates constitute a platform for the logic operations essential to computational processes.
The research is motivated by the growing needs for the miniaturisation of the systems which process information. These needs are today extending to unexpected and promising fields, such as ‘nanomedicine,’ where the possibility of carrying out logic operations at the molecular level allows the in situ analysis of a disease’s response to biomarkers to be envisaged, as well as the triggering of the response of therapeutic agents, once again in situ. At the ULg, the theoretical chemistry team led by Françoise Remacle specialises in developing molecular logic machines, an area which is also at the heart of the European MOLOC research project (7th Research and Development Framework Programme), co-ordinated by the Liège researcher.
‘We demonstrate that the library of DNAzymes, designed and synthesized by Professor Willner’s team, allows for the realization of a complete ensemble of logic gates which can be used to compute any Boolean function. We also show that these gates can be concatenated and that their dynamical assembly into circuits can be directed by selective inputs. Moreover, the design allows for the amplification of the outputs,’ explains Françoise Remacle.
In a recent publication, also in Nature Nanotechnology ("Logic implementations using a single nanoparticle–protein hybrid"), the two same universities demonstrate the feasibility of two types of logic machine: on the one hand a multiplier in base 3 (which allows more information to be processed in a single cycle) and, on the other hand, a Boolean Set-Reset sequential logic machine. The authors have proven that it is possible to carry out these two types of logic operation at room temperature on a single nanoparticle, a silicon nanoplot of 5 nanometre encapsulated in a protein obtained by genetic engineering and deposited on a gold surface.
The authors have also demonstrated that several operations can be carried out successively on two nanoparticles deposited on the gold surface, which opens the way to the assembly of a network of nanoparticles, thus scaling up the computational capacity.
Source: University of Liège