Poly-L-histidine coated microfluidic devices for bacterial DNA purification without chaotropic solutions

Chemical Trends in Sample Preparation for Nucleic Acid Amplification Testing (NAAT): A Review

Nucleic acid amplification testing facilitates the detection of disease through specific genomic sequences and is attractive for point-of-need testing (PONT); in particular, the early detection of microorganisms can alert early response systems to protect the public and ecosystems from widespread outbreaks of biological threats, including infectious diseases. Prior to nucleic acid amplification and detection, extensive sample preparation techniques are required to free nucleic acids and extract them from the sample matrix. Sample preparation is critical to maximize the sensitivity and reliability of testing. As the enzymatic amplification reactions can be sensitive to inhibitors from the sample, as well as from chemicals used for lysis and extraction, avoiding inhibition is a significant challenge, particularly when minimising liquid handling steps is also desirable for the translation of the assay to a portable format for PONT. The reagents used in sample preparation for nucleic acid testing, covering lysis and NA extraction (binding, washing, and elution), are reviewed with a focus on their suitability for use in PONT.

DNA Binding to the Silica: Cooperative Adsorption in Action

The adsorption and desorption of nucleic acid to a solid surface is ubiquitous in various research areas like pharmaceutics, nanotechnology, molecular biology, and molecular electronics. In spite of this widespread importance, it is still not well understood how the negatively charged deoxyribonucleic acid (DNA) binds to the negatively charged silica surface in an aqueous solution. In this article, we study the adsorption of DNA to the silica surface using both modeling and experiments and shed light on the complicated binding (DNA to silica) process. The binding agent mediated DNA adsorption was elegantly captured by cooperative Langmuir model. Bulk-depletion experiments were performed to conclude the necessity of a positively charged binding agent for efficient DNA binding, which complements the findings from the model. A profound understanding of DNA binding will help to tune various processes for efficient nucleic acid extraction and purification. However, this work goes beyond the DNA binding and can shed light on other binding agent mediated surface-surface, surface-molecule, molecule-molecule interaction.