How Actuated Particles Effectively Capture Biomolecular Targets

Abstract

Because of their high surface-to-volume ratio and adaptable surface functionalization, particles are widely used in bioanalytical methods to capture molecular targets. In this article, a comprehensive study is reported of the effectiveness of protein capture by actuated magnetic particles. Association rate constants are quantified in experiments as well as in Brownian dynamics simulations for different particle actuation configurations. The data reveal how the association rate depends on the particle velocity, particle density, and particle assembly characteristics. Interestingly, single particles appear to exhibit target depletion zones near their surface, caused by the high density of capture molecules. The depletion effects are even more limiting in cases with high particle densities. The depletion effects are overcome and protein capture rates are enhanced by applying dynamic particle actuation, resulting in an increase in the association rate constants by up to 2 orders of magnitude.

Nanoscale Mapping Functional Sites on Nanoparticles by Points Accumulation for Imaging in Nanoscale Topography (PAINT)

“…Very relevantly, only the functional molecules that are properly exposed to the solvent will be recognized by the docking strands, thereby providing a highly selective identification of the active sites. This is of crucial importance, as many reports have highlighted the issues of wrongly oriented antibodies for targeting and molecular diagnostics. − Notably, as there is no need for direct labeling, e . g ., covalent conjugation of fluorophores to the protein of interest, this method allows performing super-resolution on the native material.…”

Pre-concentration by liquid intake by paper (P-CLIP): a new technique for large volumes and digital microfluidics

“…We propose that in the future, both the incubation time and error may be reduced by coupling a high-capacity reservoir with the DMF device and using more efficient mixing by magnetic actuation. 48 Further, the experiment presented here was designed as a head-to-head comparison, keeping the total number of particles the same between conventional and P-CLIP DMF immunoassays. It is likely that by increasing the number of particles used with P-CLIP, incubationtimes could be decreased while still allowing large samples to be processed by DMF.…”

Nanomaterials for Healthcare Biosensing Applications

“…Some inorganic nanomaterials, such as Fe 3 O 4 , demonstrate a magnetic nature and can be easily manipulated by an external magnetic field, allowing simple extraction and buffer replacement, and also provide a high signal-to-noise ratio in biological samples, in addition to their large surface area [143,144,145,146]. They can be used for homogenising, trapping, enriching, transporting, and labelling of analytes, especially in POC testing.…”