Target‐Induced and Equipment‐Free DNA Amplification with a Simple Paper Device

We report on a paper device capable of carrying out target‐induced rolling circle amplification (RCA) to produce massive DNA amplicons that can be easily visualized. Interestingly, we observed that RCA was more proficient on paper than in solution, which we attribute to a significantly higher localized concentration of immobilized DNA. Furthermore, we have successfully engineered a fully functional paper device for sensitive DNA or microRNA detection via printing of all RCA‐enabling molecules within a polymeric sugar film formed from pullulan, which was integrated with the paper device. This encapsulation not only stabilizes the entrapped reagents at room temperature but also enables colorimetric bioassays with minimal steps.     

Biocomputing for Portable,Resettable, and Quantitative Point‐of‐Care Diagnostics: Making the Glucose Meter a Logic‐Gate Responsive Device for Measuring Many Clinically Relevant Targets

It is recognized that biocomputing can provide intelligent solutions to complex biosensing projects. However, it remains challenging to transform biomolecular logic gates into convenient, portable, resettable and quantitative sensing systems for point‐of‐care (POC) diagnostics in a low‐resource setting. To overcome these limitations, the first design of biocomputing on personal glucose meters (PGMs) is reported, which utilizes glucose and the reduced form of nicotinamide adenine dinucleotide as signal outputs, DNAzymes and protein enzymes as building blocks, and demonstrates a general platform for installing logic‐gate responses (YES, NOT, INHIBIT, NOR, NAND, and OR) to a variety of biological species, such as cations (Na⁺), anions (citrate), organic metabolites (adenosine diphosphate and adenosine triphosphate) and enzymes (pyruvate kinase, alkaline phosphatase, and alcohol dehydrogenases). A concatenated logical gate platform that is resettable is also demonstrated. The system is highly modular and can be generally applied to POC diagnostics of many diseases, such as hyponatremia, hypernatremia, and hemolytic anemia. In addition to broadening the clinical applications of the PGM, the method reported opens a new avenue in biomolecular logic gates for the development of intelligent POC devices for on‐site applications.