2017 – Case 13a: According to the World Health Organization, antibiotic resistance development is one of the biggest threats to global health, food security and development today. To decrease unnecessary use of antibiotics in agriculture, the iGEM TU Delft DreamTeam 2017 aimed to create an affordable, user-friendly diagnostic tool able to detect antibiotic resistance genes. To this end, they used a recently discovered enzyme known as Cas13a/C2c2. Upon recognition of its target RNA, Cas13a is activated and engages in collateral cleavage of non-target RNAs. This allows for conversion of the target recognition into an optical readout. In addition to the specificity, the team also worked on making the detection system cellfree and easily portable.
2016 – Opticoli: Microscopes have been around for hundreds of years and the technology behind these devices has been quickly developing over the past centuries. Microscopy has already helped us to image cells into great detail, which is essential for the identification of mechanisms behind diseases such as Alzheimer’s, of which we still don’t know the exact mechanism, but also for developing synthetic biology even further. In this age, the technology and knowledge of microscopy is no longer limiting for making detailed images of the cell; it’s the cells itself. When using fluorescence microscopy, a fluorescent cell only emits a limited number of photons, a part of this will not reach the detector. 2016 iGEMTU Delft team used synthetic biology with the aim of improving fluorescence microscopy. There were two research lines: producing biological lenses and inventing a bacterial laser.
2015 – Biolink: The printing system, called Biolink, can be summarized in the following sentence: biofilm producing bacteria are printed with the help of a flexible scaffold hydrogel. First of all, the homemade bacteria (modified to make biofilms) are mixed with a solution of sodium alginate and subsequently with calcium chloride. There, the Ca2+ molecules keep the structure fixed creating a stable gel. This hydrogel-bacteria mixture is then induced with rhamnose, a sugar specific for our promoter, which makes them synthesize CsgA, the linking molecule. CsgA proteins polymerize to an amyloid structure surrounding the cells and connecting them to each other through the scaffold. Once the cells are all attached in the structure defined by the gel scaffold, it is no longer necessary. Consequently, the hydrogel is dissolved with sodium citrate. But the cells are still connected due to the curli amyloid! So, they obtained a perfectly defined 3D structure made of bacteria.
2014 – Electrace: Project Electrace consisted of three parallel Modules, termed Electron Transport, Conductive Curli and Landmine Detection. Of fundamental interest was the Module Electron Transport. Team iGEM 2014 TU Delft integrated the Mtr system of metal-reducing bacterium Shewanella oneidensis in E. coli. Upon induction, the transmembrane MtrCAB protein complex formed, which enabled the bacterium to transport electrons to the extracellular environment, generating a measurable current output. To optimize this system, the intricate protein complex formation process was modeled in Deterministic Model of EET Complex Assembly . Also, Flux Balance Analysis was employed to increase generation of electrons and thus transport via E. coli carbon metabolism.
2013 – Peptidor: 2013’s team engineered Escherichia coli that can detect MRSA in order to locally produce and deliver antimicrobial peptides.
2012 – Snifferomyces: Snifferomyces is a modular system, used in the detection of volatile compounds. It has in the membrane a G-protein–coupled receptor that can bind to a specific signal, once bound it then switches on a signaling machinery which transmits this information over the plasma membrane and through the cell to produce a Quantitative response in the form of fluorescence. Using the Snifferomyces, the aim was to develop a universal olfactory system which allows scientists to introduce olfactory receptors in yeast with minimal effort.
2011 – StickE.coli: The goal of the project was to grant a new ability to bacteria: stickiness. Bacteria don’t have hands to hold themselves to a certain spot, which leaves them susceptible to whatever flow is currently present. This is advantagous when we want to clean “bad” bacteria off our dishes! But when one wants to use “good” bacteria, it can be very handy to keep them at one spot. Think of sticking a disease-sensing bacterium on disease-risky spots or enabling probiotics to always be at the right place. In industry controlling the attachment of bacteria allows for interesting new purification possibilities.
2010 – Alkane degradation: Formation of BioBricks for the degradation of n-alkanes to n-alkanols followed by the conversion to n-alkanals and finally n-alkanoic acids. The biobricks were implemented in Escherichia coli K12 and characterized and evaluated based on their alkane degrading capabilities.
2009 – Bacterial Relay Race: The team wanted to build an improved cell to cell communication system. They choose this subject since most applications or tasks in their synthetic biological systems were generally completed by a population of cells, not a single cell. Gaining new insights into cell to cell communication and designing manageable cell to cell communication systems allows for a wide range of new possibilities. Manageable cell to cell communication systems could have applications in different fields like therapeutic applications or fermentation technology applications. They attempted to construct an E.coli strain which is capable of passing a GFP signal through conjugation to other E.coli cells only once, with communication appearing population wide. Their work built on projects of previous iGEM teams from UC Berkeley and Peking University.
2008 – RNA Thermometer: The project comprised of several research goals. The first goal was to construct an RNA thermometer in vivo. Because it is probably not feasible to construct the whole system in the time available they focused on several subgoals that would help them create the RNA thermometer in future. These subgoals were: providing a sound theoretical basis for the functioning of an in vivo RNA thermometer, designing and testing temperature sensitive stretches of RNA and cloning protein coding sequences of enzymes involved in the color pathway. They focused on standardizing all parts made during the project according to iGEM regulations. The second goal was to predict behavior of this system using computer models. The third goal was to focus on ethical considerations of synthetic biology in general (on a macro scale) and the implications of using synthetic biology within the open source technology setting of iGEM (on a micro level).