Blood-Plasma Separators

Yang, S., Uendar, A., Zahn, J. D. A microfluidic device for continuous, real time blood plasma separation. Lab on a Chip, 2006, 6, 871-880. 

Lee MG, Choi S, Kim H-J, Lim HK, Kim J-H, Huh N, Park J-K (2011) Inertial blood plasma separation in a contraction-expansion array microchannel. Appl Phys Lett 98 253702... 

Yeo LY, Friend JR, Arifin DR (2006) Electric tempest in a teacup - the tea leaf analogy to microfluidic blood plasma separation. Appl Phys Lett 89 103516... 

Based on a similar principle, Yang et al. [9] have developed a microfluidic device for continuous, real-time blood plasma separation from whole blood. The device is composed of a blood inlet, a bifurcating region which leads to a purified plasma outlet, and a concentrated blood cell outlet. They have precisely designed flow rate ratios at each bifurcation so that no blood cells (erythrocytes, leukocytes, or platelets) flow into the side channels, while blood plasma is skimmed into the purified plasma collection channels. The experimentally determined plasma selectivity with respect to blood hematocrit level was almost 100 % regardless of the inlet hematocrit (Fig. 7a). The total plasma separation volume percent varied from 15 % to 25 % with increasing inlet hematocrit (Fig. 7b). 

A snapshot of the blood plasma separation region (40 X magnification,... 

Blood-plasma separators Filters Microporous materials Microporous membranes... 

Atifin DR, Yeo LY, Friend JR (2007) Microlluidic blood plasma separation via bulk electrohy-drodynamic flows. Biomicrolluidics 1(1) 14103. doi 10.1063/l. 2409629... 

Yang S, Ji B, Undar A, Zahn JD (2006) Microfluidic devices for continuous blood plasma separation and analysis during pediatric cardiopulmonary bypass procedures. ASAIO J 52 698-704... 

Filters Microporous membranes Microporous materials Blood-plasma separators... 

Whole blood is seldom used ia modem blood transfusion. Blood is separated into its components. Transfusion therapy optimizes the use of the blood components, using each for a specific need. Red cell concentrates are used for patients needing oxygen transport, platelets are used for hemostasis, and plasma is used as a volume expander or a source of proteins needed for clotting of the blood. 

A method for the fractionation of plasma, allowing albumin, y-globulin, and fibrinogen to become available for clinical use, was developed during World War II (see also Fractionation, blood-plasma fractionation). A stainless steel blood cell separation bowl, developed in the early 1950s, was the earhest blood cell separator. A disposable polycarbonate version of the separation device, now known as the Haemonetics Latham bowl for its inventor, was first used to collect platelets from a blood donor in 1971. Another cell separation rotor was developed to faciUtate white cell collections. This donut-shaped rotor has evolved to the advanced separation chamber of the COBE Spectra apheresis machine. 

Blood components are also collected through apheresis. In apheresis, advanced blood cell separators are used to collect one or more specific blood components from a donor. The cell separators collect blood iato a separation chamber, isolate the desired blood components, and return the blood components not needed to the donor. This procedure is performed on-line within one sterile disposable tubiag set. The two principal components collected through apheresis are plasma and siagle-donor platelets (SDP). 

The special design of the Latham bowl allows for a specific blood cell separation known as SURGE. This technique makes use of the principle of critical velocity. The Latham bowl is filled until the huffy coat, ie, layer of platelets and white cells, moves in front of the bowl optics. At this point the machine starts to recirculate plasma through the bowl at increasing rates. The smallest particles, ie, platelets, ate the first to leave the bowl. Their high number causes the effluent line to turn foggy. The optical density of the fluid in the effluent line is monitored by the line sensor. A special algorithm then determines when to open and close the appropriate valves, as well as the optimum recirculation rate. 

Separation media, with bimodal chemistry, are generally designed for the complete separation of complex samples, such as blood plasma serum, that typically contain molecules differing in properties such as size, charge, and polarity. The major principle of bifunctional separation relies on the pore size and functional difference in the media. For example, a polymer bead with hydrophilic large pores and hydrophobic small pores will not interact with and retain large molecules such as proteins, but will interact with and retain small molecules such as drugs and metabolites. 

Organophosphates, such as methyl parathion, are known to inhibit cholinesterase activity. A method has been developed to measure the extent of this inhibition and relate it to organophosphate exposure (EPA 1980d Nabb and Whitfield 1967). In this EPA-recommended method, blood is separated into plasma and red blood cell fractions. The fractions are treated with saline solution, brought to pH 8 with sodium hydroxide, and dosed with acetylcholine perchlorate. The ensuing acetic acid releasing enzyme reaction... 

Since the order of increasing CL intensity for alkyl amines reacted with Ru(bpy)32+ is tertiary amines > secondary amines > primary amines, pharmaceutical compounds bearing a tertiary amine function (e.g., antihistamine drugs [99], anticholinergic drugs [100], erythromycin [101], and its derivatives [102]) have been sensitively determined after HPLC separation (Table 3). The method was applied to the detection of d- and L-tryptophan (Trp) after separation by a ligand-exchange HPLC [103], The detection limits for d- and L-Trp were both 0.2 pmol per injection. Oxalate in urine and blood plasma samples has also been determined by a reversed-phase ion-pair HPLC (Fig. 18) [104], Direct addition of... 

As liquid chromatography plays a dominant role in chemical separations, advancements in the field of LC-NMR and the availability of commercial LC-NMR instrumentation in several formats has contributed to the widespread acceptance of hyphenated NMR techniques. The different methods for sampling and data acquisition, as well as selected applications will be discussed in this section. LC-NMR has found a wide range of applications including structure elucidation of natural products, studies of drug metabolism, transformation of environmental contaminants, structure determination of pharmaceutical impurities, and analysis of biofiuids such as urine and blood plasma. Readers interested in an in-depth treatment of this topic are referred to the recent book on this subject [25]. 

In addition to murein, bacterial polysaccharides include dextrans—glucose polymers that are mostly al 6-linked and al 3-branched. In water, dextrans form viscous slimes or gels that are used for chromatographic separation of macromolecules after chemical treatment (see p.78). Dextrans are also used as components of blood plasma substitutes (plasma expanders) and foodstuffs. 

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