Combating small molecule environmental contaminants: detection and sequestration using functional nucleic acids.

Small molecule contaminants pose a significant threat to the environment and human health. While regulations are in place for allowed limits in many countries, detection and remediation of contaminants in more resource-limited settings and everyday environmental sources remains a challenge. Functional nucleic acids, including aptamers and DNA enzymes, have emerged as powerful options for addressing this challenge due to their ability to non-covalently interact with small molecule targets.

Systematically Modulating Aptamer Affinity and Specificity by Guanosine-to-Inosine Substitution.

Aptamers are widely used in small molecule detection applications due to their specificity, stability, and cost effectiveness. One key challenge in utilizing aptamers in sensors is matching the binding affinity of the aptamer to the desired concentration range for analyte detection. The most common methods for modulating affinity have inherent limitations, such as the likelihood of drastic changes in aptamer folding.

RE-SELEX: restriction enzyme-based evolution of structure-switching aptamer biosensors.

Aptamers are widely employed as recognition elements in small molecule biosensors due to their ability to recognize small molecule targets with high affinity and selectivity. Structure-switching aptamers are particularly promising for biosensing applications because target-induced conformational change can be directly linked to a functional output. However, traditional evolution methods do not select for the significant conformational change needed to create structure-switching biosensors.

Thermoreversible Control of Nucleic Acid Structure and Function with Glyoxal Caging.

Controlling the structure and activity of nucleic acids dramatically expands their potential for application in therapeutics, biosensing, nanotechnology, and biocomputing. Several methods have been developed to impart responsiveness of DNA and RNA to small-molecule and light-based stimuli. However, heat-triggered control of nucleic acids has remained largely unexplored, leaving a significant gap in responsive nucleic acid technology.

Solution rheological parameters modulate calcium phosphate mineralization in a microfluidic device.

Mineralization of calcium phosphate and other materials in vivo and in natural water sources occurs in solutions that are not stagnant, but are flowing. Flow conditions could influence solution mixing and, therefore, mineralization kinetics or mechanism. This work describes the design and characterization of a multi-stream parallel flow microfluidic device that allows for controlled solution mixing and indirect control of laminar flow by altering the microfluidic device width, shape, length, flow rate, and flow velocity.

Quantification of hypoglycin A and methylenecyclopropylglycine in human plasma by HPLC-MS/MS.

Hypoglycin A (HGA) and methylenecyclopropylglycine (MCPG) are naturally-occurring amino acids known to cause hypoglycemia and encephalopathy. Exposure to one or both toxins through the ingestion of common soapberry (Sapindaceae) fruits are documented in illness outbreaks throughout the world. Jamaican Vomiting Sickness (JVS) and seasonal pasture myopathy (SPM, horses) are linked to HGA exposure from unripe ackee fruit and box elder seeds, respectively.

Quantitative HPLC-MS/MS analysis of toxins in soapberry seeds: Methylenecyclopropylglycine and hypoglycin A.

Methylenecyclcopropylglycine (MCPG) and hypoglycin A (HGA) are naturally occurring amino acids found in various soapberry (Sapindaceae) fruits. These toxins have been linked to illnesses worldwide and were recently implicated in Asian outbreaks of acute hypoglycemic encephalopathy. In a previous joint agricultural and public health investigation, we developed an analytical method capable of evaluating MCPG and HGA concentrations in soapberry fruit arils as well as a clinical method for the urinary metabolites of the toxins.