Rohit

Hi I'm Rohit Bandaru. I'm from Chelmsford, Massachusetts, about an hour 15 minute commute. I am a rising junior at Chelmsford High School. Science is my favorite subject. I am very involved in my school's science club which participates in Science Olympiad and other events. Biology has never been my favorite field of science. I have always been more interested in chemistry and physics. But, I have realized that biology is inarguably the most exciting field of science. This realization brought me to this program. Also, I have heard a lot about synthetic biology in recent years, and is definitely a potential college major.

Design/Research project The Integration of Mechanical and Biological Systems: The Future of Technology by, Rohit Bandaru

**Intro:** During the industrial revolution, we mastered mechanical technology. We have machines that can do nearly everything we need them to. But traditional mechanical technology has its limitations. We have recently started using biology to fill the gaps in the potential of mechanical systems. We are currently in the beginning of the next industrial revolution: the synthetic biology revolution. We have used engineered biology to manufacture drugs, detect certain chemicals, make fuel, and other tasks that mechanical machines can’t do as well. Mechanical and biological technology each have their respective limits. Biological systems are messy, hard to control, unstable, and prone to potentially harmful mutations. But they are smarter, self-regulating, and more compatible in organic environments and in synthesizing and reacting to organic molecules. Mechanical machines are easier to control, they can’t mutate to something harmful or useless, and they can function in a wider range of environmental conditions. Future technology will not have these two aspects working at high levels separately, as most people imagine. We will redefine technology by integrating biology and mechanical technology to make the most out of each type of system. Our future machines will contain living tissues, synthetic microbes, and DNA code, as well as gears, electric circuits, metal frames, and computer code. This type of mixed integrated technology will have unimaginable power. To show how biology can work with machines, I’ve designed a device. Synthetically created bacteria will interact with a device by generating an electric current. A small metal strip will be placed in water with the bacteria. It will act as a relay which will activate a device, if a strong enough current goes through it. In response to a stimulus, for example a certain harmful chemical, the bacteria will use quorum sensing to group on the metal strip and produce electric current. Then, the attached device could remove the chemical from the water or alert an operator. This simple system shows how biology can work with an electric mechanical system. Most modern technology operates on electric signals, so electricity is the best way for bacteria to interact with machines.

**Design:** If bacteria can easily generate an electric current, it will be easier for them to work with machines. We know this is possible because a certain deep sea bacteria, //Shewanella oneidensis//, can generate electric currents in the presence of heavy metals such as iron. Surface proteins on the bacteria allow a metabolic pathway transporting electrons to extracellular acceptors. This protein transfers electrons best to iron ions, but it will work great with the relay. The bacteria will be E. coli, modified to include genetic features from //Shewanella oneidensis// MR-1. It will have two metabolic pathways. One of which will be standard E. coli metabolism, and another one will the //S. oneidensis//’ metal reducing electric metabolism. In the presence of a stimulating molecule, the bacteria will use electric metabolism. //S. oneidensis// also uses pili to move towards an electron acceptor, in this case, the relay. The bacteria will form a biofilm on the metal relay when stimulated. A GFP gene can also be incorporated for a visual sign that can be observed by a human operator or detected by a light sensor on the machine. This device will simply use the GFP as reporter. It will act as verification if necessary that the relay is activated by the bacteria. The cells will have electricity conducting nanowires, which are modified pili. This is a part of the chassis that will boost effectivity. Quorum sensing in this bacteria will be used to amplify a chemical signal. So a few stimulating molecules, can activate the electric functions of the whole bacterial population. The stimulating molecule to attach to a surface receptor releasing a molecule that will activate a gene for the production of the quorum sensing molecule or pheromone. The molecule will go to other cells’ pheromone receptors and its own cell’s receptors. The receptors will release activators that will activate the promoters for the AHL production gene, and also the main open reading frame. The amplification of a chemical signal makes the machine much more effective in detecting small quantities of the chemical. The open reading frame will turn on the electric metabolism. It will code for the cytochromes, which are the surface proteins that secrete the electrons outside the cell, the enzymes necessary for this metabolism, molecules that inhibit regular metabolism, and also the proteins needed for motility, biofilm formation, nanowires, and //Shewanella oneidensis//’ tendency to move toward metal. I will not list the specific genes and proteins. But they are readily available from the sequenced genomes of //E. coli// and //S. oneidensis.//


 * **Stimulating Molecule** || **Regular Metabolism** || **Electric Metabolism** ||
 * 0 || 1 || 0 ||
 * 1 || 0 || 1 ||

**Conclusion:** This shows how bacteria can work with a mechanical system. The integration of biology and mechanics shown here demonstrates how using both can erase some limits to technology. A mechanical sensor would be less accurate and wouldn’t be able to continuously probe a large volume of water. Whereas there would be a bacterium present nearly everywhere in the water. Also the bacteria allow for more precision, a single molecule would be enough to set off the system, rather than certain concentration. However potential problems arise with this device. There needs to a mechanism to control the sensitivity of the biosensing. For some uses, only a certain concentration of the stimulus molecule is of any significance. Also it wouldn’t work if there is a large quantity of iron ions or electron acceptors in the water. The relay has to be the best option for transferring electric current. Testing will be needed to create the most effective, accurate, and precise design. There are a lot of variables that will need to decided and tweaked, including the right metabolic enzyme, the most effective inhibitors of regular metabolism, chassis for electric conductivity (nanowires), and gene expression. With the right choices, this device has a lot of potential. Nevertheless it shows how biology and machines could possibly work together. Biology and machines are bound to intersect. A great new field will arise to transform technology as we know it. **Bibliography:** [] [] __[|http://www.britannica.com/EBchecked/topic/182915/electricity/71583/Bioelectric-effects#toc71583]__ (bioelectric effects) [] [] [] [] [] [] []