Analytical Chemistry on the Femtoliter Scale

Abstract

The compartmentalization of reactions in femtoliter (fL) containers and integration of fL containers into arrays not only enhances and accelerates chemical and biochemical analysis but also leads to new scientific methods and insights. This review introduces various fL container and array formats and explores their applications for the detection and characterization of biologically relevant analytes. By loading analytes, sensing elements, or cells into fL arrays, one can perform thousands of analytical measurements in parallel. Confining single enzyme molecules in fL arrays enables one to analyze large numbers of individual enzyme molecules simultaneously in solution. New nanofabrication techniques and progressively more sensitive detection methods drive the field of fL analytical chemistry. This review focuses on the progress and challenges in the field of fL analytical chemistry with examples of both basic and applied research.

Post-Genomics Nanotechnology Is Gaining Momentum: Nanoproteomics and Applications in Life Sciences

“…This technology has been developed in studying single enzyme molecules, detection of low abundance protein biomarkers in biological fluids, and single cell analysis (Malhotra et al, 2012;Rusling et al, 2013). Since the properties of single molecules significantly differ from the bulk solution, this method enabled detailed studies of single proteins and their kinetic properties, as illustrated by Gorris and Walt (2010). Also, detection of low femtomolar biomarker proteins was achieved utilizing such techniques (for reviews, see Gorris and Walt, 2010;LaFratta and Walt, 2008;Rissin and Walt, 2006).…”

“…Since the properties of single molecules significantly differ from the bulk solution, this method enabled detailed studies of single proteins and their kinetic properties, as illustrated by Gorris and Walt (2010). Also, detection of low femtomolar biomarker proteins was achieved utilizing such techniques (for reviews, see Gorris and Walt, 2010;LaFratta and Walt, 2008;Rissin and Walt, 2006). The principle of detection enhancement basically relies on Poisson Statistics, dictating that at very low concentration values, femtoliter size reaction chambers may contain either one or no molecules (Rissin et al, 2010).…”

Tuning the Dual Emission of Photon‐Upconverting Nanoparticles for Ratiometric Multiplexed Encoding

“…[ 1 ] Consequently, multiplexed analyte detection has greatly facilitated such diverse applications as genotyping, [ 2 ] screening combinatorial libraries, [ 3 ] medical diagnostics, [ 4 ] and environmental monitoring. [ 5 ] The number of analytes that can be investigated in parallel, however, is ultimately limited by the available identifi er codes.…”

Hydrolysis of a Lipid Membrane by Single Enzyme Molecules: Accurate Determination of Kinetic Parameters

“…[1] Biological molecules of particular relevance in this context are enzymes, which are catalysts accelerating essential biochemical reactions with high efficiency and fidelity. When experiments are performed in the single-molecule regime, the concentration of the active enzyme becomes irrelevant for the determination of the specific enzymatic activity, [2] and simultaneously it is not necessary to synchronize the onset of catalytic activity of multiple enzymes. This approach has provided new insights on static and dynamic heterogeneities in enzymatic reactions, [3] fluctuations of catalytic reaction rates, [4] and conformational changes during substrate conversion.…”

“…For this scheme, the conventional mass-action law equations can easily be solved in the steady-state approximation for the SE concentration, and the reaction rate per enzyme is given by Equation (2).…”