Density-Based Separation of Microparticles Using Magnetic Levitation Technology Integrated on Lensless Holographic Microscopy Platform

Abstract

Microparticle/cell separation is one of the most important applications in the field of biomedical sciences particularly for cell sorting and protein assays. There are variety of different separation technologies introduced in the literature that the main limitations are large amount of sample, expensive chemical use besides of requirement of a labeling procedure (i.e. fluorescent/magnetic labeling), complex machinery, and high operational costs. Magnetic levitationbased separation offers simple, rapid and precise separation of microparticles based on their densities by suspending them in a glass microcapillary between two opposing magnets. Traditionally, magnetic levitation-based microparticle separation and identification procedure is performed by imaging under bulky microscopes composed of fragile and expensive optics and require trained personnel to operate which makes the whole procedure costly, time consuming and prone to human error. Lensless digital inline holographic microscope (LDIHM) eliminates the need for sophisticated optics by replacing simple illumination and recording scheme that can be reduced into few widely-available and cost-effective components. Thus, inspection procedure is mostly carried out on digitally processing captured holograms so that dependency on optical components and human error is dramatically reduced alongside using cost-effective and handheld device. Here, we introduce a novel hybrid platform that brings the advantages of magnetic levitation system with lensless digital inline holographic microscope for precise separation and identification of microparticles based on their densities. In the platform, it was shown that 1.026 g/mL and 1.090 g/mL microparticles were successfully identified.

Magnetic Susceptibility-Based Protein Detection Using Magnetic Levitation

“…The protein analysis with the presented strategy was conducted directly on a simple bright-field microscope with a more straightforward method that does not require complex instrumentation, numerous washing, and incubation steps unlike conventional ELISA. Moreover, magnetic nanoparticles could be adopted in ultrasensitive and automated on-chip protein analysis platforms. , For a remote and portable protein analysis, this assay could be adopted to low-cost and portable imaging systems such as cellular phones, lensless holographic microscopy systems, , and self-contained and handheld magnetic levitation devices. , In addition, integration of the assay into flow-assisted magnetic levitation devices could enable analyzing higher sample sizes and hence increasing the sensitivity of protein detection.…”

“…Moreover, magnetic nanoparticles could be adopted in ultrasensitive and automated on-chip protein analysis platforms. 15,65 For a remote and portable protein analysis, this assay could be adopted to low-cost and portable imaging systems such as cellular phones, 27 lensless holographic microscopy systems, 66,67 and self-contained and handheld magnetic levitation devices. 68,69 In addition, integration of the assay into flow-assisted magnetic levitation devices 70 could enable analyzing higher sample sizes and hence increasing the sensitivity of protein detection.…”

A Vacuum-Integrated Centrifugal Microfluidic Chip for Density-Based Separation of Microparticles

“…When the magnetic force and buoyancy force act on the particle equilibrate, levitation occurs, and particles are levitated in a different height according to their densities. Magnetic levitation based cell separation offers point-of-care diagnostic [7]. Suspended microchannel resonators can measure single cell density with high precision and accuracy [8].…”