Concurrent quantification of multiple nanoparticle bound states

Abstract

Purpose:The binding of nanoparticles to in vivo targets impacts their use for medical imaging, therapy, and the study of diseases and disease biomarkers. Though an array of techniques can detect binding in vitro, the search for a robust in vivo method continues. The spectral response of magnetic nanoparticles can be influenced by a variety of changes in their physical environment including viscosity and binding. Here, the authors show that nanoparticles in these different environmental states produce spectral responses, which are sufficiently unique to allow for simultaneous quantification of the proportion of nanoparticles within each state. Methods: The authors measured the response to restricted Brownian motion using an array of magnetic nanoparticle designs. With a chosen optimal particle type, the authors prepared particle samples in three distinct environmental states. Various combinations of particles within these three states were measured concurrently and the authors attempted to solve for the quantity of particles within each physical state. Results: The authors found the spectral response of the nanoparticles to be sufficiently unique to allow for accurate quantification of up to three bound states with errors on the order of 1.5%. Furthermore, the authors discuss numerous paths for translating these measurements to in vivo applications. Conclusions: Multiple nanoparticle environmental states can be concurrently quantified using the spectral response of the particles. Such an ability, if translated to the in vivo realm, could provide valuable information about the fate of nanoparticles in vivo or improve the efficacy of nanoparticle based treatments.

The use of magnetic nanoparticles in thermal therapy monitoring and screening: Localization and imaging (invited)

“…1. (A) The most common implementations of MPI were modeled by recording all of the harmonics with signal: [1,63], [2,63], [3,63], [4,63]. It uses a large sinusoidal field and a large gradient field.…”

“…It uses a large sinusoidal field and a large gradient field. (B) We have proposed using a more limited number of harmonics to localize the nanoparticle distribution: [1,7], [2,7], [3,7], or [4,7]. (C) The "wavelet like" implementation is obtained by recording pairs of harmonics: [1,2] or [2,3] or [3,4].…”

Colorize magnetic nanoparticles using a search coil based testing method

“…Magnetization curve of nanoparticles in our experiment is measured using a vibrating sample magnetometer (VSM) at room temperature shown in Fig. 1 [6,7] or the parameters of MNP solution [8], and others used the amplitude ratio of the 5th ( ± f f 4 H L ) over 3rd harmonic to characterize MNPs [1,9]. In this paper, we analyze both amplitudes and phases of the 3rd and 5th harmonics in order to reduce the magnetic colorization error.…”

MSB estimation of bound fraction: bias from binding energy uncertainty

“…The accuracy has been shown to be high for two and three bound states. Accuracies of half of one percent have been achieved when characterizing two bound states and accuracies of one percent have been achieved when characterizing three bound states [4]. The accuracy obviously also depends on how different the bound states are: two bound states that are almost the same are more difficult to separate.…”