Lightsheet-based flow cytometer for whole blood with the ability for the magnetic retrieval of objects from the blood flow

Abstract

Detection and extraction of circulating tumor cells and other rare objects in the bloodstream are of great interest for modern diagnostics, but devices that can solve this problem for the whole blood volume of laboratory animals are still rare. Here we have developed SPIM-based lightsheet flow cytometer for the detection of fluorescently-labeled objects in whole blood. The bypass channel between two blood vessels connected with the external flow cell was used to visualize, detect, and magnetically separate fluorescently-labeled objects without hydrodynamic focusing. Carriers for targeted drug delivery were used as model objects to test the device performance. They were injected into the bloodstream of the rat, detected fluorescently, and then captured from the bloodstream by a magnetic separator prior to filtration in organs. Carriers extracted from the whole blood were studied by a number of in vitro methods.

Effect of Size on Magnetic Polyelectrolyte Microcapsules Behavior: Biodistribution, Circulation Time, Interactions with Blood Cells and Immune System

“…The structure of LbL-assembled capsule shell was (MNPs) n /(Parg/DS) 2 /Parg/BSA-FITC/Parg/DS, where n is number of FIL cycles. Then, different types of microcapsules suspended in phosphate saline buffer (PBS) were passed through the flow cell of the previously described, light-sheet-based flow cytometry system [14]. The flow velocity was around 30 µL/min (≈10 mm/s), which is close to the blood flow velocity in femoral veins of small laboratory animals [14].…”

“…The optical design of the device is based on a simplified variant of the SPIM-Fluid imaging flow cytometer [20] and described in detail in our previous publication [14]. The major features are shown in Figure 1.…”

“…The efficiency of the microcapsules' capture by the external source of the magnetic field was evaluated using the custom-built, lightsheet-based flow cytometer [14]. For this, the suspension of capsules labeled with FITC was passed through the flow cell with a velocity of around 30 µL/min.…”

“…One of the most commonly used combinations of biocompatible and biodegradable polymers for LbL assembly is polyarginine (Parg)/dextran sulfate (DS), indicated by the tremendous number of articles published in the last decade [6,7,10,11,[14][15][16]. However, despite the profound interest in magnetic Parg/DS microcapsules, the cytotoxicity, hemotoxicity, and systemic side effects induced by their application have not been properly studied to date.…”

Serial imaging of micro-agents and cancer cell spheroids in a microfluidic channel using multicolor fluorescence microscopy

“…The simplest way is to collect multicolor images using a combination of an imaging sensor and single-band filters. Individual fluorescence images are collected by changing the filters with different bandwidths [ 23 , 26 , 27 ]. However, performing imaging by positioning the filters either manually or using a motorized drive creates a delay and limits the image acquisition rate.…”