Fluorescence analysis of carrier rat and human erythrocytes loaded with FITC-dextran

Abstract

Rat and human erythrocytes are inherently different with respect to slow dialysis encapsulation used in preparing carrier erythrocytes. The incorporation process, commonly measured with radioactive tracers, is always larger in human erythrocytes, mainly because the rat carrier cells are more fragile. When FITC‐Dextran (Dx) is used in the encapsulation process, and loaded rat and human RBCs are studied by fluorescence intensity, some additional events are evident. Not all cells of each population appear with a fluorescence signal, and not all show similar fluorescence intensity. Human RBCs show a higher percentage of marked cells and a higher fluorescence intensity than rat RBCs. Two populations, of high and low fluorescence, appear in FITC‐Dx loaded rat erythrocytes. The human loaded RBCs show a similar peak distribution together with another peak in the middle scale of fluorescence. Therefore, a heterogeneity in the cell population as a result of the encapsulation process is manifested for both species. The fractionation of RBCs, loaded with either FITC‐Dx or 125I‐CA, by centrifugation on Ficoll‐Paque reveals that the low density cells have much more substance incorporation than the counterpart cell subpopulation in the pellet. Therefore, the cell modifications produced by the encapsulation process are independent of the substance being incorporated. On the other hand, FITC‐Dx, but not 125I‐CA, shows a certain degree of association to RBCs membranes, especially in humans. © 1996 Wiley‐Liss, Inc.

Critical Features for Mesoporous Silica Nanoparticles Encapsulated into Erythrocytes

“…RMSN-PEG-10 exhibit successful incorporation into the RBCs compared to the larger sizes of particles (25, 50, and 200 nm), which indicated that RBC membrane pores allow a preferential embedding of nanoparticles with smaller sizes (Figure ). Actually RMSN-PEG-10 suspended in HEPES buffer have a Z -average = 26.4 ± 0.75 nm due to hydration and some slight aggregation , (Table S2), which meant that the selection of the particle sizes of RMSN for encapsulation in RBCs by hypotonic treatment requires a hydrodynamic diameter below about 30 nm. To verify the structural integrity of the engineered RMSN-RBCs, the interior of the cells was examined via confocal and scanning electron microscopy (SEM) imaging.…”

“…4,5,11,12 Hypotonic dialysis is based on the exposure of RBCs to the substance to be encapsulated contained in a dialysis bag to the hypotonic buffer, so that nanoparticles can enter RBCs, and the pores were resealed in an isotonic buffer. 24,25 To confirm the integrity of the hypotonic dialysis method in this study, FITC−dextran acts as a positive control 26 which shows the emission of green fluorescence on the RBCs (denoted as dextran@RBCs) in Figure S4. RMSN-PEG-10 exhibit successful incorporation into the RBCs compared to the larger sizes of particles (25, 50, and 200 nm), which indicated that RBC membrane pores allow a preferential embedding of nanoparticles with smaller sizes (Figure 3).…”

Endocytotic uptake of nutrients in carnivorous plants

“…Additional fluorescent markers were used in N. coccinea and Drosera capensis in order to confirm the results gained by FITC‐BSA: FITC‐Dextran has been shown to label endocytotic compartments in animal (Lencer et al. , 1990; Alvarez et al. , 1996) and plant cells (Cole et al.…”

Blood analyte sensing using fluorescent dye-loaded red blood cells

“…15,16 The various benefits of RBC carriers (e.g., biocompatibility, biodegradability, protection of drug from body, protection of body from drug) has resulted in a significant body of research on RBC-based drug delivery. 17,18,19 Compared with drug delivery applications, little research has been performed on loading fluorescent materials into RBCs. FITC-dextran was loaded into RBCs by Alvarez et al and Scott et al; a broad distribution of fluorescence intensities was revealed upon analysis by cell sorting methods.…”