NON-INVASIVE COLLECTION MEANS AND METHOD

Technical Field The present application relates to the collection of blood, blood-tissue and disease components. Most particu- larly, it relates to a method and apparatus for the non- invasive transcutaneous collection of such components from a human or animal.

Background Art In the past, researchers and clinicians requiring a sample of the blood of an animal usually have obtained that sample by either piercing or nicking the skin of the animal and then collecting the sample from a vein or artery. At times the sample was collected with the assistance of a vacuum. It would obviously be advantageous to have a method of collecting blood and blood components which does not require the piercing or nicking of the skin.

Disclosure of the Invention The general objects of the present invention are to disclose a non-invasive method for the collection of blood, blood-tissue, and disease components from a man or an animal and to disclose a device for conveniently practicing the method.

Briefly stated, the present invention comprises pre- treating the external surface of an area of the skin (epidermis, epithelial cells) of a human or animal to clean off dead cells and increase the permeability of the skin to blood components, forming a liquid coating and

wetting the skin, forming a superficial contusion on that area of the skin without nicking or piercing the skin, and then, with the aid of the liquid coating and vacuum, collecting a skin transudate containing the desired components from the area of the contusion. The transudate collected is suitable for diagnostic purposes.

The preferred device of the present invention com¬ prises a probe having a cup-shaped member for holding a coating liquid and forming a seal with the skin at one end and means for receiving a sealed vacuum tube at the other end. The probe includes a deflector positioned within and partially filling the cup-shaped member and means for opening the seal of the vacuum tube when the cup-shaped member is sealed against the skin so that the deflector and vacuum cooperate to form a contusion and the vacuum and a coating of liquid on the skin cooperate to transfer a skin transudate into the vacuum tube.

In the drawings:

Fig. 1 is a perspective view of a preferred embodi- ment of the device for use in the method of the present invention;'

Fig. 2 is an end _. view taken along lines 2-2 in Fig.

1;

Fig. 3 is an exploded view showing the parts of the probe of the device of Fig. 1 prior to assembly;

Fig. 4 is an exploded view showing the parts of the collection tube of the device of Fig. 1;

Fig. 5 is a schematic view showing the device ^' applied to the skin in the practice of the method of the present invention; and

Fig. 6 is an illustration showing the contusion formed upon the skin.

In Fig. 1 to 4 of the drawings, there is shown a preferred embodiment of a device which can be used in the practice of the method of the present invention. The device 10 as seen in Fig. 1 consists of a probe 11 and a collection tube 12.

Referring to Figs. 1 to 5, it can be seen that the probe 11 includes a hollow-cylindrical housing 13 which is open at one end 14 to receive the collection tube 12. The other end 15 of the housing is closed except for a tubular central inlet 16. As seen only in Fig. 5 the inside of the inlet 16 is threaded as at 17 to receive a needle assembly 18 having a hub 19. When the needle assembly 18 is secured in the inlet 16 as seen in Fig. 1 a sharp piercing end 20 of a needle 21 projects into the housing 13. A tubular projection 22 extends outwardly from the other end of the hub 19 of the needle assembly. As seen best in Fig. 5 the hub 19 fits within a central bore 23 of a cup-shaped member 24, preferably of resilient rubber, which is part of the tip 25 of the probe 11. As seen only in Fig. 3, the tip 25 also includes a solid mushroom-shaped deflector 26, preferably of rigid plastic, which has a stem 27 adapted to fit loosely into the other end of the bore 23 of the cup-shaped member 24 and a locking ring 28 for keeping the head 26a of deflector 26 properly positioned in place in a circular recess 29 in the outer end of the cup-shaped member 24.

As seen best in Fig. 2, when the deflector 26 is properly positioned in the cup-shaped member 24 an opening 30 exists between the outside of the head 26a of deflector 26 and the inside of the recess 29 of the rubber ring 24. Turning to Figs. 4 and 5, it can be seen that the collection tube 12 includes a glass or plastic tube 31 which is closed at one end 32 and open at the other end 33. In the completely assembled collection tube 12, as seen in Fig. 1, the open end 33 is closed by a solid resealable stopper 34. The inner end of the stopper 34 has a central recess 35 seen only in Fig. 5 in which a small fluid collection trap 36 for the transudate is locked in place by a locking ring 37. The interior of the assembled tube 12 including the trap 36 is at a reduced pressure or vacuum. The trap 36 can be made of a gas permeable plastic or have a vent hole to insure that

its interior is also at a reduced pressure (e.g. 100-400 mm Hg. ) .

As seen in Figures 1 and 5 the cylindrical housing 13 is sized to serve as holder for the vacuum tube 12. In Fig. 1, the tube 12 is shown sealed and in Fig. 5 the tube 12 is shown advanced within the holder 13 with the needle assembly.18 piercing the stopper 34 of the tube 12. Prior to preloading the cup-shaped member with coating liquid the tube 12 can be partially advanced so that the needle point 20 is closed by but has not com¬ pletely pierced the resealable stopper 24.

In the preferred practice of the method of the present invention an area of the skin of the donor is first pretreated for one minute with a solution to clean off dead cells and to preferably raise blood cells to the surface. The probe tip 25 of the device 10 is preloaded with a coating liquid then quickly pressed against the pretreated skin as seen in Fig. 5. The liquid in the probe tip 25 forms a liquid coating on ^" the skin which increases skin permeability and assists the transfer of the transudate to the vacuum tube. Keeping the outer portion of the cup-shaped member 24 in contact with the skin the collection tube 12 is then advanced within the housing 13 until the point 20 of the needle 21 penetrates the resealable stopper 34. Because of cooperation of the deflector 26 and the reduced pressure in the collection tube 12 a contusion is formed similar to that illustrated in Fig. 6 and the liquid on the skin, including any blood, blood-tissue, or disease related components from the area of the contusion within the boundary of the recess 29, is sucked through the opening 30 and trans¬ ported via the needle assembly 18 into the collection trap 36.

Although a specific device for forming the contusion and collecting the desired components has been illustrated and described, it will be apparent to those skilled in the ^" art that other types of devices which form a contusion

and/or provide vacuum assistance can be used in the collection of blood components in accord with the teaching of the present invention. Devices that have been con¬ structed and successfully tested include those in which the probe tip is comprised of cups of elastic rubber or rigid plastic which are nipple-like or cone-shaped and those in which the probe tip includes in place of the mushroom-shaped deflector, a member which is star-shaped, or formed of concentric rings or beads. The described collection tube is an evacuated tube but the vacuum, if desired, also could be supplied by a vacuum pump (mechanical, electric, aspirator) hydraulic fluid movement, a syringe, chemical vacuum or even mouth suction. The components possibly could also be collected from the area of the contusion without vacuum assistance, if desired. It does appear, however, that the collection of extrudate or transudate is enhanced by reducing the atmospheric pressure on the skin within the area of the probe tip. Devices could also be employed in which the needle assembly is simply a channel or tube with a piercing tip and which includes a control valve or clamp. In addition, the collection trap could be a series of connected tubes joined by a constriction, a port leading to a diagnostic device, or simply a piece of sponge-like material which could be used as such in a diagnostic test or from which the collected blood components could be recovered.

Although the use of a single pretreatment solution has been described, additional pre-treatment solutions could be used. They might be applied by spraying or in a gel-like binder, or with a bandage-like applicator. In the preferred practice of the method of the present invention, the skin is first washed with a solu¬ tion and then treated with a coating liquid comprising an hypotonic solution containing a vasoconstrictor, a surface active agent and an anticoagulant.

The solution which removes dead cells and contami¬ nants contains a surface active agent such as a nonionic detergent and an antiseptic agent to sterilize the skin to avoid infection, such as ethanol, iodine or antibiot¬ ics. The solution can also be used as the coating liquid and may contain solvents such as polyvinyl acetate, acetone and dimethylsulfoxide (DMSO) to change the permea¬ bility of skin membranes, an analgesic and a gel or cream of high viscosity to help the probe tip form a seal with the skin. The solution can also contain anticoagulants, hormones and buffering with carrier molecules to avoid nonspecific losses due to binding or deterioration and to promote preservation.

The preferred solution contains the following ingredients:

COMPONENTS OF THE PRETREATMENT SOLUTION

Generic Name Preferred Concentration Active Component Concentration Range, , Active

(a) Carbamide 5% in a water- 3 - 1. Peroxide free w/v gel base ^'

(b) Tetrahydrozo- .025% w/v 0.02 - .05% line hydro- chloride

(c) Alkylaryl 3.0% v/v 0.05 - 5.0% Polyether Alcohol

(d) Heparin-Ammonium 50 IU/cc 5 - 100 IU/cc

Generic Name Preferred Concentration Active Component Concentration Range, Active

(e) Phosphate .05M Buffer pH 4-8

Buffered (pH 7.2) Saline .45M NaCl 0.2 -.9M

Solution (PBS) NaCl

In addition to tetrahydrozoline HC1 (0.05%) other vasoconstricting or vasodilating compounds may be used, such as phenylephrine hydrochloride. Vasodilators are preferred if more blood cells as compared to immunoglo- bulins are desired.

In addition to the surface active agent used other surface active agents providing the same function and not having any detrimental effects can also be used. Repre- sentative of such surface active agents are the following: Guanidinium chloride, merc ptoethanol or other nonionic or ionic detergents.

The preferred anticoagulant solution contains ammonium heparin. ^" However, other anticoagulants which may be used include the following: ethylenediaminetetraacetic acid (EDTA) (0.02%), sodium heparin, sodium citrate, strepto- kinase or streptodornase.

Other cleansing agents than carbamide peroxide may be used such as methyl salicylate 15.0% in methanol 70% v/v, ethanol, paraben, methylparaben, providone iodine, phenol (0.5%) antibiotics, dimethyl sulfoxide, acetone, polyvinylacetate, polyvinyl alcohol, mineral oil, propylene glycol, or polyethylene glycol. In addition an anti-bubble agent may be added. If desired, a pain depressing agent such as benzocaine or triethanolamine salicylate or a heat stimulating agent like methylsalicylate also may be included along with volatile solvents such as ether. Still further the addition of mild enzyme solutions such as trypsin may be useful, depending on the blood com- ponent desired in the extrudate.

. The preferred method of collecting blood components comprises: a) Applying carbomide peroxide (Proxigel) (1-2 drops) to a portion of hairless skin such as the forearm for 10 seconds. b) Applying two drops of a hypotonic buffered solution containing Triton X-100, ammonium heparin, and Visine onto the gel, mixing until bubbles appear - about 10 seconds. c) Pressing the probe tip 25 (preloaded with the solution used in b for forming a liquid coating), firmly to the treated skin. d) Forming a contusion by activating the vacuum by moving the tube 12 within the housing 13 until the needle 21 pierces the stopper 34 of the vacuum tube while maintaining contact with the skin for 1-2 minutes. e) Stopping the action when the skin extrudate or transudate is collected in the trap. f) Wiping the skin area with alcohol or a suitable antiseptic. The preferred method results in the skin being visibly affected. It is reddened and a small "hickey" or contusion is formed. It appears that only microcapil- laries are broken allowing the contusion to quickly heal and greatly reducing the risk of infection. A small sample, 1-2 drops, of extrudate is trapped in the collec¬ tion trap. The skin is obviously still intact. There is no bleeding evident, no scab formation takes place, no clotting evidence appears, no visible scratches, nicks or piercing of the skin occurs and no infections result. There is no pain, only the reddened area or contusion which usually disappears within 10 minutes to 2 days.

The transudate or extrudate contains red blood cell

6 —3 ghosts (e.g. 10 per cc or 10 whole blood) as viewed with a light microscope. It also contains immunoglobulin which can be verified by immuno-assay (e.g. latex aggluti-

nation) and by radioimmuno-diffusion. Cell components can be isolated or identified by differential centrifuga- tion, concentration, staining and microscopy. The ex¬ trudate can also be analyzed for proteinaceous components by electrophoresis, carbohydrates by colorimetric methods and specific drugs and chemicals by commercial or other assays.

In addition to the specific device shown in the drawings for making the contusion, other types of devices can be used including mechanical devices to form the superficial contusion such as gentle pinching or pressing devices, with or without vacuum.

The trap (36) can be fabricated in many useful configurations. Traps have been constructed with minor changes in shapes that will perform the following functions.

1. Filtration of the specimen.

2. Column purification.

3. Mixing with a series of chemicals in steps. 4. Storage of reactants separately, yet allowing easy mixing. 5. Growing micro-organisms.

Post treatment of the skin after the contusion with 70% isopropyl alcohol helps prevent any possibility of infection or irritation. In addition, post treatment of the extrudate or transudate aids in preparing and pre¬ serving the specimen for use in a diagnostic test. For example: the extrudate or transudate may be further diluted with buffers such as phosphate-saline, Tris-HCl, hepes, boric acid-sodium borate. The diluent can contain protease inhibitors (i.e. dithiothreitol, lmM) or other ingredients to help purify the component to be tested (i.e. Affigel-Blue, Biorad Co., to remove albumin; Protein A, from staphlococcus A, to bind up IgG; Calcium Chloride to help remove fibrin) .

Losses of desired constituents by nonspecific absorp¬ tion can be prevented by precoating the internal surfaces

of the collection device components with silicon or proteins. Preservatives such as paraben or antibiotics also may be used.

The permeability of the skin (membranes of the epidermis and dermis) for diffusion of blood components is variably dependent upon:

1. The balance of blood pressure and atmospheric pressure;

2. The integrity of the membrane barrier; 3. active transport;

4. relative concentration, solubility and size of components;

5. hydrophobic and ionic forces between macromole- cules; 6. temperature; and

7. pH (Hydrogen ion concentration) and ionic strength. The method of the present invention through use of a - pretreatment solution and coating liquid can suitably adjust these variables to obtain a sample of body fluid directly through the skin without pain or discomfort. The practice of the present invention is further illustrated by the examples which follow.

EXAMPLE I; Subject - Male, Age 41. A small (about 2 cm 2) area of the skin on the forearm was treated with carbamide peroxide (2 drops, 10 seconds) followed by 2 drops of solution (c) 3% v/v, solution (d) ammonium heparin 50 IU/cc, solution (b) 50% v/v in phosphate buffered saline (PBS) (.05M Buffer pH 7.2, 0.45 M NaCl) for 10 seconds until bubbles appeared. Then the probe tip of the mechanical device shown in Figs. 1 to 4 (prewetted with one drop of the above solution) was applied to the skin. The collection tube assembly was moved within the housing to activate the vacuum. Suction was maintained for 2 minutes and halted by pulling away the probe tip from the skin.

The skin was not broken; and only a small superficial contusion (hickey) resulted and that disappeared in 48 hours.

The extrudate obtained in the collection trap was removed by cutting off the tip of the trap and squeezing the rubber stopper. The extrudate was tested for blood components. The results were as follows:

Red Blood Cells (RBC) Hemoglobin and myoglobin were detected by means of their strong pseudoperixidase action to catalyze chromogens on a paper strip; color change to dark green indicated greater than 250 erythrocyte equiva¬ lents per μL (1/1000 dilution of whole blood). The reaction is slow due to excess substrate. Caution, of course, must be exercised to avoid false positives due to pretreatment solutions.

Leukocytes were detected by their esterases which -catalyze the hydrolysis of an indoxylcarbonic acid ester to indoxyl. The indoxyl formed reacted with diazonium to produce a purple color.

Hematohistons (immunoglobulins) were detected by radial immunodiffusion (RID) IgG, IgM, IgA were detected quanti¬ tatively by their precipitating immune rings in anti- globulin containing gels. The results indicated that the extrudate contained immunoglobulines at about 1/100 the concentration as compared to undiluted serum (IgG 2.0, IgM 3.0, IgA 25 IU/cc) .

Thus the invention is useful for detection of hemo- toplasmopathy, (i.e. extremely high proportionate immuno- globulin results of RID would indicate multiple myeloma) (in newborns elevated IgM indicates acute infection). Although the yield of cells is very low, about 1/1000,

the yield of macromolecules is better and is 1/100 as compared to whole blood.

Glucose was detected at about 0.25 mg/dl by a colorimetic reaction using a specific glucose-oxidase/peroxidase method and a hexokinase glucose 6-phosphate dehydrogenose assay.

Protein was determined as about 100 mg/dl by color change of the indicator 3', 3", 5', 5" - tetrachlorophenol - 3, 4. 5. 6 - tetrabromosulfopthalein. EXAMPLE II:

Subject - Female, Age 36. A small (about 2 cm 2) area of the skin on the forearm was treated with 2 drops of solution (b): PBS (1:1) for about 10 seconds. The cone-shaped probe tip of a device made from nonflexible plastic which was connected to a vacuum- source (mechanical pump: 250 mm of Hg) was pressed against the treated skin for 60 seconds with a fluid trap in series. About 3 drops of extrudate was recovered. The extrudate was tested for blood components as follows: Blood Cells were detected by light microscopy in a

6 2 hemacytometer to read about 5 x 10 . RBC/mm were

3 counted equalling a 1/10 dilution of whole blood.

After staining with Wright stain, leukocytes and RBC were observed at 320 x using a Carl Zeitz microscope. Abnormal red blood cells would have diagnosed malaria or sickle cell anemia. Thus, this method could be useful for hematomacy, proving its diag¬ nostic value.

Hundreds of such determinations were made using various other mechanical devices described and the pre¬ ferred concentration of pretreatment solutions was deter¬ mined empirically.

EXAMPLE III A feasibility pilot study for obtaining Herpes viruses for a culture from clinically suspicious lesions

utilizing the preferred device of the present invention was performed on four volunteer subjects with skin lesions, clinically suspicious for Herpes Simplex virus infection. The four volunteer subjects consisted of three males and one female between the ages of nineteen and twenty-eight years of age.

The purpose of the feasibility study was to determine whether the preferred device of the present invention was effective in collecting viable Herpes virus from clini- cally suspicious lesions.

Clinically suspicious lesions, unruptured vesicles, were identified on all patients. The lesions were first cleaned with an alcohol swab, mechanically ruptured, and swabbed as per usual accepted clinical technique for routine Herpes cultures. Following the routine harvesting procedures, other lesions on the same patients were sampled via the method of the present invention utilizing sterile "Hanks" balanced salt solution as the preloading solution. Samples obtained by the conventional technique were labeled as culture specimens A; patients numbered 1 through 4. Samples obtained via the method of the present invention were labeled culture specimens B; patients 1 through 4. All sample specimens were prepared via the Viral Culture Kit Analysis Method, utilizing indirect monoclonal antibodies, immunoperoxidase staining technique with parallel slides being stained with a modified May Grunwald Giemsa stain to evaluate viral cytopathic effect (Vero cell line). Cultures A and B from patients 1, 2, and 3 revealed the presence of diagnostic cytopathic effect on modified May Grunwald Giemsa staining, confirmed by indirect monoclonal antibody immunoperoxidase staining. Patient 4 cultures A and B were both negative.

This pilot study indicates that the preferred device of the present invention is at least as effective and sensitive as traditional lesion viral culturing methods, and in some cases may be more sensitive. (Patient 3 demonstrated diagnostic cytopathic effect on modified May

Grunwald Giemsa staining within 24 hours from the time the specimen was collected using the method of the present •invention. )

EXAMPLE IV A male 43 year old was sampled for total bacteria per centimeter square (cm ² ) of skin.

A preferred device as seen in the drawings was sterilized with 70% ethanol, preloaded with sterile saline, and applied to various skin sites, arm, leg, foot, to collect material.

A comparison of "dirty" and freshly washed skin was made by culturing the resulting samples on a rich nutrient medium. As expected, the uncleansed skin had much more detectable bacteria. Even freshly cleansed skin contained about 1000 bacteria per cm . These were nonpathogenic organisms; but the method used in conjunction with the appropriate test could be used to diagnose pathogens.

EXAMPLE V Six nondiabetic patients and six diabetic patients were tested using the preferred device and method of the present invention to collect specimens. A colorimetric assay for glucose was employed.

Many assays were performed for each individual. The results were compared to direct blood tests using a similar assay. The results indicated that total glucose values obtained with the device and method of the present invention paralleled the blood values obtained from direct blood tests when plotted against time before and after glucose intake. Triglycerides were also elevated after glucose intake.

A hypotonic saline pretreatment solution was used allowing 30 seconds contact before forming the contusion for most tests. Total glucose results also could be stimulated by using other additives such as glycerol. When no liquid pretreatment was used, no glucose could be found in the specimens collected. The use of other types

of devices (i.e., without a deflector which pinches off an area of skin) gave irreproducible results.

EXAMPLE VI A forty-three year old male was tested using the device and method of the present invention. The device was kept in contact with skin for extended periods of time. A variety of liquid pretreatments were used with essentially the same result. After about sixty minutes of application, a blood blister was raised on the skin and a pink (hemoglobin containing) solution was obtained. The resulting lesions took more than one week to disappear.

EXAMPLE VII A forty-three year old male was tested, using the method and device of the present invention and various pretreatment solutions for the collection of electrolytes (sodium and potassium). Ion specific electrodes indicated the presence of the electrolytes in the transudates collected. In several tests the ratio of the two ions appeared to correlate with blood levels. Dimethylsulfoxide was found to increase the yields of electrolytes five-fold over the use of aqueous pretreatment solutions. Some more aggresive (i.e., detergent containing) solutions were found to encourage proportionately higher potassium levels, indicating cell disruption. A variety of cell debris was observed in samples; therefore, tests specific for cell contents could be performed.

EXAMPLE VIII A forty-three year old male was tested, with the device of the drawings using hypotonic saline as a pre¬ treatment solution, for amino acids and protein in transudates. In a short time of application (30 seconds) equivalent reproducible amounts were detected as compared to 5 minute applications. Since phenylalanine (PA) is one of the amino acids, it is possible that this approach could be used to detect PA elevated due to phenylketonuria

(PKU). Other genetic defects or inborn errors of metabo¬ lism probably could be diagnosed using specific tests.

It will be apparent to those skilled in the art that there are many reasons why it may be preferable to use the present invention rather than pierce the skin with a lance or needle. The procedure of the present invention is non—invasive and therefore has less chance of secondary infection when components are pre-sterilized and used in a sanitary manner. The method is painless. The extrudate may be obtained by the donor or another person in a one-hand operation, without technical expertise, and is essentially foolproof. The site of extraction is less precise than that required for phlebotomies. Therefore, a sample could be obtained more easily from infants or others with small and damaged veins or in emergency situations. In addition, the method and device are of great potential value in the development of diagnostic tests that require plasma or other fluid for home health care and consumer performed diagnostics. For example, the method and device could be used to extract disease components, including bacteria, from the skin or skin lesions, such as pustules and the like.