Abstract: A silica-silicone fluid gel, the properties of which are not significantly affected by sterilizing doses of radiation, is prepared by reaction of a silicone fluid having a narrow viscosity distribution with a filler material and a network former at or below about 120.degree. C.

Abstract: A method to facilitate the analysis of uncoagulated blood, for example freshly drawn blood or heparin blood, wherein the blood is filled into a test tube of plastic and a porous, elastic body in which one or more ballast element optionally are embedded, is placed in the upper layer of the blood and the blood is centrifuged such that the body in friction contact with the inner surface of the test tube is pressed through the blood, wherein the body or bodies are of glass or another suitable material with a surface whose characteristics correspond to those of glass, and where in addition there is used an overlying layer of small beads or other particles whose specific gravity is adapted in such a way that the beads after the centrifugation are embedded in the fibrin layer as reinforcement, and further wherein the two features may be combined by utilzing only the described small beads. A means for carrying out the method is also described.

Abstract: The disclosure is of an improved assembly, compositions and method for the separation of blood into its light, liquid and heavy, substantially cellular phases with insertion of a non-Newtonian fluid between the phases as a barrier. The improvement comprises using as the non-Newtonian fluid, one which has substantially time independent rheological properties and a controlled yield stress value. The improved assemblies of the invention have enhanced shelf-lives and improved reliability of operation. The preferred assemblies may be sterilized by irradiation and the disclosure is also of a method for their manufacture.

Abstract: A serum and cell separating and dispensing device comprising an elongated tubular vessel partitioned throughout its length forming two distinct compartments containing vent orifices on either side. One open end of the vessel is fitted with a resilient element containing a larger and smaller orifice respectively. These orifices communicate with the two compartments respectively. At the opposite end of the vessel are two small tubular vessels extending from and communicating with the compartments formed by the partition. Blood drawn in an evacuated collection tube such as Becton Dickinson's vacutainer is centrifuged after clotting. The device is forced into the open end of the collection tube and pressed downwardly. The resilient element forms an air trap by touching the inner wall of the collection tube and serum is forced through the orifice communicating with the serum compartment.

Abstract: This invention relates to a method and apparatus for the fractionation of a suspension of finely divided solid particles differing in sedimentation velocity, such as platelets and other blood cells. The separation of, for instance, platelet-rich plasma (PRP) from whole blood is accomplished by centrifuging the blood sample in a bag and by injecting into its outer centrifugal end a volume of saline which displaces the PRP from the blood sample after red cells have been sedimented away from the other end of the bag. The preferred apparatus is designed as a closed system of interconnected bags held in a support made to fit a large centrifuge bucket. The flow of liquid is generated by placing the saline-containing bag closer to the center of rotation while positioning the collection bag at a farthest distance from this center. The discharge of PRP from the separation bag into the collection bag is facilitated by making the inner centrifugal end of the separation bag to collapse in response to centrifugal force.

Abstract: A blood collection tube is provided with a blood phase partitioning device disposed in the upper portion or adjacent the low density blood phase end of the tube. The device carries blood phase barrier gel-like material which flows through a restricted orifice in the device to meter or reduce the flow rate of the material into the blood during centrifugation to suitably delay the formation of the complete phase barrier until complete blood phase separation has taken place.

Abstract: Disclosed is a method for centrifuging serum which comprises steps of introducing a barrier having an elastic porous member at least at its principle part into a blood-collecting tube and centrifuging serum, the elastic porous member having porosity of 40% or more, continuous-pore size of 50 to 400 .mu., and a cross section larger than that of the blood-collecting tube. Also disclosed is a barrier to be introduced into a blood-collecting tube, comprising an elastic porous member having porosity of 40% or more, continuous-pore size of 50 to 400 .mu., and a cross section larger than that of the blood-collecting tube, the bottom portion of the elastic porous member preferably being a relatively hard portion with smaller outside diameter.

Abstract: An apparatus (10,50) is provided for physically retaining a reagent (17) in a blood collection tube (11) separate from a blood sample until the tube (11) is centrifuged. The apparatus includes a cup-shaped flexible barrier (10,50) placed over the reagent (17) disposed in the bottom of the tube (11). The barrier (10,50) seals with the inner wall of the tube (11) and prevents the reagent (17) from entering the tube's upper evacuated chamber (12,55) into which the blood sample is drawn. The seal maintains the barrier (10,50) in position until the tube (11) is centrifuged whereupon the barrier (10,50) moves to the bottom of the tube (11) causing the reagent (17) to flow past the barrier (10,50) to mix with the blood sample.

Abstract: This invention relates to a method and apparatus for the separation of finely divided solid particles dissimilar in size and/or density, such as platelets and other blood cells. The separation of, for instance, platelets is accomplished by subjecting the blood sample to centrifugal force in the chamber while displacing the platelets from the blood sample by injecting a relatively small volume of saline into the centrifugally outer end of the chamber. In the preferred apparatus, the saline is injected into che blood sample by driving the chamber supporting the blood sample into a saline filled cavity under the influence of centrifugal force.

Abstract: This invention relates to an apparatus for separating platelets from blood samples by subjecting the blood sample to centrifugal force in the chamber while displacing the platelets from the blood sample by injecting a relatively small volume of saline into the centrifugally outer end of the chamber. In the preferred apparatus, the saline is injected into the blood sample by driving the chamber supporting the blood sample against a saline filled collapsible cavity under the influence of centrifugal force.

Abstract: An improved assembly for use in the centrifugal separation of serum or plasma from blood is disclosed. A tubular glass container has therein a body of gel-like material having a yield stress value such as to permit it to flow and form a transverse barrier between the separated phases of blood upon centrifugation. This container is provided with an hydrophobic inner surface portion adjacent to said barrier to enhance the adhesion of the barrier material to the container wall and inhibit leakage across the barrier of the separated blood components.

Abstract: A pre-packaged blood collecting and separating device and process of its preparation are disclosed in which the device contains a mixture of liquid polybutadiene and an inorganic, inert filler, such as silica, as a thixotropic gel adapted at rest to form a sealing barrier between separated blood phases. The device and gel are subjected to sterilizing radiation to form a substantially sterile device, substantially free of backflow contamination, without degradation of the physical properties of the gel.

Abstract: This invention provides a liquid separating composition containing as a base material a liquid polymer of hydrocarbon or derivatives thereof having a viscosity ranging from 100 to 20,000 CP at 20.degree. C., suitable amounts of additives for adjusting the specific gravity and viscosity of the composition and a netword former for imparting a thixotropic property to the composition. This invention also provides an apparatus for applying a liquid separating composition, comprising a vessel filled with a liquid separating composition, and a cannula fixed to the vessel, for piercing into a rubber cap of a liquid container.The liquid separating composition is transferred to the liquid container by centrifuging the apparatus connected to the liquid container.

Abstract: A self-contained separator assembly comprises a container having at least one end open which is adapted to receive blood for subsequent separation into a light phase comprising plasma or serum and a heavy phase comprising the formed elements of blood. A closure is sealed into the open end of the container which may be penetrated by a cannula through which blood may be received into the container. A piston-like plug which forms a seal against the container wall is characterized by an average specific gravity so as to permit the plug to be centrifuged through a blood sample toward the interface of the heavy phase and the light phase. The plug comprises a valve seating portion having a valve opening therein and a valve head adapted to seat on the seating portion and bias means extending between the seating portion and the valve head to bias the head to the seated position on the seating portion after centrifugation.

Abstract: A fluid collection device includes a blood collection tube having a negative pressure therein and sealed at one end by a stopper pierceable by a needle cannula for drawing a blood specimen into the tube for centrifugal separation into a relatively light phase, plasma or serum, and a relatively heavy phase including the blood cells. A quantity of a gel-like mixture of liquid hydrocarbon-polymer, such as polybutene, and an inorganic powder, such as silica powder, is disposed in the tube. The gel-like mixture has a specific gravity intermediate those of the relatively light and heavy phases of the blood so that during centrifugation, the gel-like mixture moves to a position between the phases to provide a partition barrier between them.

Abstract: A device is provided for collecting and separating a two-phase liquid, and for dispensing the light phase. The device provides improved structure such that the dispensing aperture is protected from premature liquid contact by a partition. Upon phase separation, the partition automatically allows flow of the light phase to the aperture.

Abstract: A device for use in blood centrifugation processes, said device comprising a centrifuge tube containing a substantially rigid separator element and said tube having walls of predetermined thickness and material of construction to enable flexing of only that portion of the tube wall coincident with said separator element, sufficient to enable passage of liquid by said separator element, in response to centrifugal force.

Abstract: A fluid collection device for receiving a liquid, such as blood, and which is adapted to be centrifuged to separate it into its relatively light and heavy phases. The collection device has a phase partitioning device having a specific gravity intermediate those of the light and heavy phases of the blood so that it automatically moves during centrifugation to substantially the interface of the phases to sealingly partition them from each other. The device has a resilient sealing member which is of conical or "umbrella" configuration, and another member of different specific gravity connected to the sealing member and having stabilizing members for maintaining the sealing member properly oriented in the container. The sealing member partially collapses during centrifugation to allow blood components to pass by the sealing member.

Abstract: A blood collection assembly and closure therefor, for the collection, separation, isolation and storage of serum from blood. The closure is constructed of a cannula penetrable self-sealing elastomer and includes a thixotropic barrier material in a hollow central portion of the closure, so that the barrier material is sealed within the closure until blood has been collected in the collection container and centrifuged. Centrifugation forces the barrier material into a collecton container through the passageway created by the cannula.

Abstract: Copolyesters are provided which are derived from mixed dibasic acids and a branched-chain diol. These copolyesters possess a unique balance of physical and chemical characteristics which permits their use in small amounts in blood separation tubes to provide an effective barrier between the light and heavy phases of the blood after centrifuging.

Abstract: The disclosure is of an improved method and apparatus for separating blood into light, substantially liquid phase and its heavy, substantially cellular phase by centrifuging a blood filled container having disposed therein an inert, gel-like barrier material possessing a density intermediate between the two phases of the blood. The improvement comprises employing a constricted tubular container, the constriction being at the zone where it is calculated the gel-like barrier material will align during centrifugation.

Abstract: Serum-Plasma separator and transfer apparatus comprising a tube and a hollow stopper-like member fitted into the open end of the tube. The top end of the stopper is of a flexible material with a weight positioned thereon. A rigid capillary tube with one end in the hollow stopper and the other end joined with a flexible capillary tube which, in turn, has its other end attached to a weighted filter. The capillary tube has a port in its side wall at the lower end adjacent the filter. As the serum is centrifuged the weighted filter drops into the tube causing the sample liquid to pass through the filter into the upper portion of the tube. At the same time the weight of the filter forces the flexible capillary tube to extend downwardly thereby opening the port in the capillary tube into the liquid sample. As the centrifuging action slows down, the weight on the stopper tend to return to its normal position.

Abstract: A device for collecting and dispensing non-pressurized liquids, comprising a collection compartment having a capillary passageway extending from an intake and along the entire sample collection length of the compartment, and a dispensing chamber.

Abstract: Uncoagulated blood is separated into components by placing the blood in a glass test tube, placing a porous, elastic body in the upper layer of the blood, and centrifuging such that the porous body in friction contact with the inner surface of the test tube is pressed down through the blood so as to form above the body a layer of serum overlying a layer of red cells which overlies the body.

Abstract: Copolyesters are provided which are derived from mixed dibasic acids and a branched-chain diol. These copolyesters possess a unique balance of physical and chemical characteristics which permits their use in small amounts in blood separation tubes to provide an effective barrier between the light and heavy phases of the blood after centrifuging.

Abstract: A collection device wherein fill-augmenting means are provided in a vented collection compartment, whereby rate of collection is increased, and capture means are provided to prevent leakage of the collected liquid out of the vent. The device is particularly useful in the collection and further processing of blood to obtain blood serum for clinical analysis.

Abstract: A blood collection device includes a tube for receiving a sample of whole blood for centrifugal separation into the lighter phase, plasma or serum, and the heavier cellular phase. The tube has a needle-pierceable stopper at the opposite end for maintaining a negative pressure in the tube. A blood phase partitioning device is disposed within the tube and includes upper and lower members with the upper member having a greater specific gravity greater than that of the lower member but together having a specific gravity between that of the lighter phase and that of the heavier phase. A sealant is disposed between the members and in contact with each member and has a specific gravity equal to the average of the two members.

Abstract: A blood serum separation unit which includes a tubular structure having openings at each of opposite ends and having a slidable disk element mounted within a base end thereof, having an outside diameter substantially less than an inside diameter of the tubular element such that upon centrifugal action the slidable disk will be slidable therewithin by torque of centrifugal action, and the tubular element being mounted substantially flushly within but removable from an outer tube having an upper open end and having a stopper-plug which when inserted plugs both the outer tubular container and the tubular element located therewithin, the plug being of a composition penetrable by a tubular needle for introducing blood from a subject to space within the tubular container and tubular element, the disk being of a specific gravity intermediate between those specific gravities of blood serum and blood coagulant precipitate whereby upon inversion of the blood-containing tube and the thereafter subjection of the same to

Abstract: Gel-like composition useful for separating and partitioning whole blood into serum and clot portions. The composition has a specific gravity between that of the serum and clot portions such that, when centrifuged in the presence of whole blood, the composition forms a chemical and physical barrier between the serum and clot portions. The composition comprises, in combination, a silicone fluid, an inert siliceous filler dispersed therein, and a network former consisting of a polysiloxane-polyoxyalkyl copolymer which stabilizes the composition by minimizing and/or avoiding "wet out" of the siliceous filler with time. The composition has a viscosity within the range of about 200,000 to about 600,000 centistokes, preferably within the range of about 350,000 to about 450,000 centistokes.

Abstract: A blood collection device includes a tube for receiving a sample of whole blood for centrifugal separation into the lighter phase, plasma or serum, and the heavier cellular phase. The tube has a needle-pierceable stopper at one end for maintaining a negative pressure in the tube. A blood phase partitioning device is disposed within the tube and includes an upper cylinder member and a lower piston member slidable in the upper member. The cylindrical member has a plurality of peripheral holes therein and a specific gravity greater than that of the piston member, with the members together having a specific gravity between that of the lighter phase and that of the heavier phase. A sealant is disposed within and in direct contact with the cylindrical member and has a specific gravity substantially equal to that of the two members together.

Abstract: A serum separation and dispensing device comprises two containers one movably mounted partially within the other, the end wall of one being sealed, in the contracted position, against the open end of the other, to hold a vacuum prior to drawing blood into the device.

Abstract: In apparatus for effecting a sealed separation or partition between two phases of a multiphase liquid upon centrifugation of the multiphase liquid, a device which facilitates access through the partition to a phase of a separated multiphase liquid which is confined between the partition and a lower or closed end of a vessel retaining such liquid.

Abstract: A bag for the separation of components in blood by gravitational settlement or centrifugation, has an upper chamber and a lower chamber connected by a slender neck, there being access conduits to each of said chambers and said neck. The bag is so dimensioned that for blood having a normal hematocrit the interfaces between packed red cells and the buffy coat and between the buffy coat and the plasma will lie within the neck. The neck can then be clamped off or otherwise sealed to separate the phases sharply and to permit virtually 100% recovery of the plasma and the packed red cells. In a second embodiment, the buffy coat can be isolated and seals within the system opened to permit intermixing of the plasma and the packed red blood cells under completely sterile conditions. A special support makes it possible for the blood bag to be subjected without distortion to centrifugation.

Abstract: A blood serum separator-dispenser capable of collecting, separating and/or dispensing is disclosed a biological fluid such as serum from an essentially closed container. A valve can be provided to separate the container into two compartments, one for serum separation and the other for serum dispensing.

Abstract: A method and apparatus for the fractionation of centrifuged density gradients have been developed. The apparatus consists of a gradient holder composed of a transparent and an opaque section which contains an opening allowing a centrifuged tube containing a density gradient having individual bands to be inserted into the holder. A displaceable piston which is suspended above the holder and is connected to an actuator may be raised or lowered into the density gradient. A standard illuminating device is placed under the gradient holder so that the exact position of each individual band can be determined. Once the precise location is determined, the displaceable piston is lowered into the gradient and by operating the actuator, the desired band of gradient can be extracted. Additionally, this method may be utilized in a continuous fractionation of the entire gradient.

Abstract: Blood serum is separated from other components of whole blood by inserting a barrier device having a specific gravity between that of the blood serum and the other blood components into a centrifuge containing a sample of whole blood, and centrifuging until the barrier device migrates to a position intermediate the blood serum and the other blood components. The preferred form of the barrier device is a truncated cone having stabilizer posts extending from the conical base parallel to the axis of the cone in the direction of truncation.

Abstract: A method for separating a blood cell portion and a liquid portion of a whole blood sample comprising the steps of contacting over a period of time a substance in the form of a nonparticulate gel mass with the sample, so as to diffuse the liquid portion into the mass, the mass having an effective pore size to exclude the blood cells, and collecting the blood cells remaining after such contact of the sample with the mass. The method may include impregnating the substance of the mass with a selective reagent to react with the liquid portion diffused therein, and furthr include analyzing a reaction product produced within the mass.

Abstract: Disclosure is made of an improved assembly for the collection, separation and isolation of serum or plasma from blood without subjecting the desired serum or plasma to contamination by exposure to the atmosphere and which utilizes a thixotropic barrier material to effect the isolation. A representative embodiment of the improved assembly comprises an air-evacuated collection chamber, a self-sealing airtight elastomeric closure for the container which is penetrable by a blood bearing cannula and a thixotrope having a specific gravity of from about 1.03 to about 1.09, held in a specially constructed reservoir positioned within the closure member and in communication with the air-evacuated chamber.

Abstract: In combination with an apparatus for centrifugally separating and partitioning differing-density phases of a multiphase fluid including a container and gel-like means initially positioned within an end portion of the container for forming a partition between the differing-density phases, the improvement comprising flow control means initially partially submerged in the gel-like means for directing the flow of the gel-like means along portions of the sidewall of the container, the flow control means having a recessed region formed in sidewall portions thereof to provide an annular space adjacent the upper surface of the gel-like means between proximal portions of the flow control element and the container. The flow control means is submerged to the extent that the upper surface of the gel-like means is positioned within the recessed region forming the annular space.

Abstract: Disclosure is made of an improved assembly for the collection, separation and isolation of serum or plasma from blood without subjecting the desired serum or plasma to contamination by exposure to the atmosphere and which utilizes a thixotropic barrier material to effect the isolation. A representative embodiment of the improved assembly comprises an air-evacuated glass collection container, a self-sealing, airtight elastomeric closure for the container which is penetrable by a blood bearing cannula and a thixotrope having a specific gravity of from about 1.03 to about 1.09 disposed in a specially constructed reservoir positioned adjacent to the closure member and within the air-evacuated collection container.

Abstract: The separation of a sample of blood into serum and clot portions is accomplished by means of a sealant consisting essentially of a silicone fluid and silica dispersed therein. The separation is accomplished by inserting a device containing a supply of the sealant into a container holding a sample of the blood, the device being characterized by a nozzle portion which extends into the sample. The container and device are centrifuged so that it separates into serum and clot portions and the sealant, having a specific gravity of at least 1.026, separates the two portions.

Abstract: A blood collection and separator assembly capable of separating blood into its component parts of plasma or serum, the light phase, and cellular portion, the heavy phase, is disclosed. The assembly comprises a container having one open end for receiving blood and a two part barrier assembly slidably disposed in the container. The outer part or shell of the latter assembly has a specific gravity greater than the light phase of blood and the inner part or plunger has a specific gravity less than the heavy phase of blood. Interposed between the two parts is a viscous sealant, such as silicone grease. After the blood separates into its light phase and heavy phase under centrifugal force, the barrier assembly is introduced so it sinks to the interface between separated phases. Upon applying further centrifugal force, the inner plunger tends to move upward while the outer shell tends to move downward thus causing a squeezing action on the interposed sealant.

Abstract: A blood collection and separator assembly of the type suitable for use in centrifuging blood to separate the plasma or serum, the light phase, from the cellular portion, the heavy phase. The assembly includes a collection container and a piston disposed therein for sealing off one phase from the other after centrifuging is terminated. The piston is formed having an average specific gravity heavier than the light phase of the blood. The piston is slidably disposed in the container with its outer surfaces in sealing contact with the inner surface of the container and is provided with means which, under centrifugal force, permit the light phase of the blood to pass the piston as the piston moves down through the light phase while retaining sealing engagement with the inner surface of the container. The piston is provided with means to stop the piston at a predetermined distance above the bottom of the container whereupon the piston can serve as an impervious barrier between the two phases of the blood.

Abstract: An evacuated tube having both ends closed has a flap type valve fixedly disposed between the ends for dividing the tube into upper and lower chambers. The valve is formed and arranged to provide a passageway between the upper and lower chambers when subjected to centrifugal forces of proper intensity and direction. Upon cessation of the force, the valve closes to provide a separation between the upper and lower chambers.

Abstract: An evacuated tube having both ends closed has a centrifugally actuated slit type valve fixedly disposed between the ends for dividing the tube into upper and lower chambers. The valve is formed and arranged to provide a passageway between the upper and lower chambers when subjected to a centrifugal force of proper intensity and direction. Upon cessation of the force, the valve closes to provide a separation between the upper and lower chambers.

Abstract: An evacuated tube having both ends closed has a ball actuated resilient aperture type valve fixedly disposed between the ends for dividing the tube into upper and lower chambers. The valve is formed and arranged to provide a passageway between the upper and lower chambers when opened by the ball subjected to a centrifugal force of proper intensity and direction. Upon cessation of the force, the valve closes to provide a separation between the upper and lower chambers.

Abstract: A self-contained fluid separator assembly is disclosed capable of separating blood into its component parts of plasma or serum, the light phase, and the cellular portion, the heavy phase. The assembly comprises a container having at least one open end for receiving blood for subsequent separation and a closure sealing the open end of the container. The closure is formed of a self-sealing elastomeric material which is penetrable by a pointed hollow needle through which the blood to be separated is conducted into the container. A piston is slidably disposed in the container with its outer surfaces in sealing contact with the inner surfaces of the container. Centrifugally actuated valve means is provided on the piston which is normally closed and automatically opens in response to centrifugal force. When blood in the container is subjected to centrifugal force it first separates into its light phase and heavy phase.

Abstract: Devices are disclosed which are useful in the simultaneous separation and filtration of the liquid portion of clotted whole blood and anti-coagulant treated whole blood. The devices are employed in novel apparatus of the invention, for the collection, separation and filtration of blood serum and blood plasma from clotted whole blood and anti-coagulant treated whole blood, respectively.