Tracking and Analyzing the Brownian Motion of Nano-objects Inside Hollow Core Fibers

Abstract

Tracking and analyzing the individual diffusion of nanoscale objects such as proteins and viruses is an important methodology in life science. Here, we show a sensor that combines the efficiency of light line illumination with the advantages of fluidic confinement. Tracking of freely diffusing nano-objects inside water-filled hollow core fibers with core diameters of tens of micrometers using elastically scattered light from the core mode allows retrieving information about the Brownian motion and the size of each particle of the investigated ensemble individually using standard tracking algorithms and the mean squared displacement analysis. Specifically, we successfully measure the diameter of every gold nanosphere in an ensemble that consists of several hundreds of 40 nm particles, with an individual precision below 17% (±8 nm). In addition, we confirm the relevance of our approach with respect to bioanalytics by analyzing 70 nm λ-phages. Overall these features, together with the strongly reduced demand for memory space, principally allows us to record thousands of frames and to achieve high frame rates for high precision tracking of nanoscale objects.

Ultrahigh numerical aperture meta-fibre for flexible optical trapping

“…To quantitatively assess the trapping performance of the meta-lens-enhanced fibre, we determined the trap stiffness at different power levels by analysing the dynamics of trapped beads. Specifically, power spectral density (PSD) evaluation 23 and mean-square-displacement (MSD) analysis 29 (both described in “Materials and methods”) were employed for determining the details for the spectral and temporal bead motion characteristics as well as for filtering out potential errors. A key benchmark performance parameter that allows for comparison to other trapping approaches is the optical trap stiffness κ = 2π k B Tf c / D , which characterizes the strength of the trap potential.…”

“…Afterwards, it is fitted to the power spectrum PSD( f) = 2D/(4π 2 (f c 2 + f 2 )) + ε 2 via a maximum likelihood estimate for statistically correlated data [46][47][48] to retrieve the fit parameters, namely, corner frequency f c (where the power spectrum drops to half) and the free particle diffusion coefficient D. In comparison, Fig. 5b illustrates the corresponding MSD calculated for the same particle displacement x ⊥,|| (t) and fitted using MSD(Δt) = 2D/ (2πf c ) • (1 − exp(−2πf c Δt)) + ε 2 including weights to compensate for correlation 29,[48][49][50] . The error, ε 2 , results from uncertainty in tracking the particle position and is a measure of the motion blur due to excessively long exposure times.…”

An Analysis Review, Detection Coronavirus Disease 2019 (COVID-19) based on Biosensor Application

“…Display a sensor that combines laser line illumination efficacy with fluidic confinement advantages. can be used to track nano-objects [139]. Showed a study of Laser spectroscopy Techniques, with advanced Femtosecond methods for a Single viral detection are all too apparent [140].…”

Ultrasensitive Exhaled Breath Sensors Based on Anti‐Resonant Hollow Core Fiber with In Situ Grown ZnO‐Bi2O3 Nanosheets

“…Recently, various semiconductor materials have been reported to be coated on optical fiber to implement the VOCs gas sensors, and the sensing mechanism is based on the induced refractive index change caused by the reaction of semiconductor material and gas molecular. [13][14][15][16][17][18] Therefore, to improve the sensing performance, it is very important to control the growth of semiconductor materials on the optical fiber. However, the current methods mainly focus on dip-coating semiconductor materials on the optical fiber, which commonly damage the original morphology features and fail to maximize material utilization.…”