Take a look at this recent publication from the Li Lab in Angewandte Chemie International Edition. In this paper, we explore a novel signal amplification strategy termed DNAzyme feedback amplification (DFA). This method takes advantage of rolling circle amplification and RNA-cleaving DNAzymes for biosensing applications, with sensitivity improvements of 3-6 orders of magnitude when compared to conventional methods. -Suraj
Checkout this recent paper from the Li Lab in Scientific Reports, “Detection of DNA Amplicons of Polymerase Chain Reaction Using Litmus Test.” Here we report on a novel DNA detection method that combines the advantages of the polymerase chain reaction with the simplicity of a litmus test. The diagnostic capabilities of the platform is demonstrated using clinically validated stool samples from C.difficile infected patients. -Suraj
Funding was recently announced to advance the Li lab’s research into rapid Legionella diagnostic technologies. Congratulations to our McMaster collaborators Dr. Carlos Filipe and Dr. John Brennan of the Biointerfaces Institute and industry partners TGWT Clean Technologies Inc., Cytodiagnostics and Mold and Bacterial Consulting Labs. Read more about it on the McMaster News website.
Sepehr Manochehry, a PhD candidate in his 3rd year, earned the coveted CIHR doctoral scholarship this year. He was ranked 6th nationwide, putting him in the top one percentile among more than 700 other applicants. His success and the focus of his research was recently featured in a news magazine article. Read it to gain a better understanding of what motivates hard-working graduates students like Sepehr. http://biochemrocks.freeflowdp.com/biochemrocks/2357984385961772?pg=23#pg23
Checkout the Li Lab’s latest paper in Nature Communications! In a collaborative project between the Li Lab and McMaster’s Biointerfaces Institute, we report a novel reporter system based on mechanically interlocked circular DNA, rolling circle amplification and DNAzymes for highly sensitive bacterial detection.
Check out the Li Lab’s latest publication in Angewandte Chemie International Edition, “Biosensing by Tandem Reactions of Structure Switching, Nucleolytic Digestion, and DNA Amplification of a DNA Assembly”. Postdoc Meng Liu has developed a novel, high sensitivity DNA based signal amplification technique using an isothermal DNA polymerase and structure switching DNA aptamers. This work brings DNA aptamer based detection technologies another step closer to convenient and cost effective point of care applications.
Evolution of an Enzyme from a Noncatalytic Nucleic Acid Sequence
Life as we know it requires thousands of biological molecules, called enzymes, which carry out chemical reactions and allow life to exist. These molecules did not appear out of thin air – they evolved out of a mixture of the Earth’s first compounds, known as prebiotic soup. One theory for how life originated is known as the “RNA World” Hypothesis: ribonucleic acid (RNA), capable of both encoding information and performing enzymatic reactions, could have been the initiator of the origins of life, bridging the gap between life and non-life.
In this project, we used a sequence of DNA as a proxy for RNA in the origins of life. Wesubjected it to a process called in vitro selection, where we randomly introduced small variations in the sequence and then obliged the sequences to carry out a reaction. The sequences were filtered – only sequences able to perform the specific reaction were permitted to survive. These unique sequences were then subjected to cycles of this process – induction of small variations, and segregation of competent sequences. Using this method, we were able to take a sequence which was incapable of an enzyme-like reaction, and evolve it with minimal changes into a sequence adept at executing the reaction. This experiment allows us a tiny peep into how RNA molecules could have acquired function at the brink of the origin of life.
Last week, our publication entitled “Translating Bacterial Detection by DNAzymes into a Litmus Test” was published in Angewante Chemie. The article was well received and was featured on several social media outlets. We were also excited to be featured on the back cover of the journal in which our very own Qian Feng conceptualized the artwork. Since then, we have put together a fantastic team to move this technology forward and to open up new avenues of research. It has been a very satisfying process to see two years of our hard work receive so much attention and we are excited to see how this technology will continue to grow!