Method and apparatus for washing objects

A device and method for washing an object in a receptacle. The device includes an end portion introducible into and cooperative with the receptacle to define a substantially enclosed space containing the object to be washed. The fluid is introduced into and aspirated from the substantially enclosed space such that the object is movable in the fluid between the end portion and the receptacle.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The invention relates to a method and device for washing and aspirating 
coated objects used in diagnostic assays. More particularly the invention 
is used to wash coated objects in the receptacles in which the diagnostic 
assay is performed. By way of further characterization, the invention 
includes a washing device which seals the receptacle into which it is 
inserted while injecting and aspirating cleaning fluid in a manner that 
produces movement of the coated object to permit complete cleaning 
thereof. 
2. Description of the Related Art 
In the diagnostic assay for the presence of hepatitis virus in blood, 
plastic beads coated with antibody are located in a tube-like receptacle 
or well. Patient serum is added to the receptacle. During incubation, 
antibody in the serum binds to the antibody. The serum is then removed 
from the receptacle and the bead is washed and aspirated with a cleaning 
fluid. Next, a reagent containing an antibody tagged with iodine-125 is 
added and binds to any antigen on the bead to form an 
antibody-antigen-antibody sandwich. The reagent is removed from the 
receptacle and the coated bead is again washed and aspirated with a 
cleaning fluid to ready the receptacle and coated bead for further 
processing in a gamma counter. 
In the processing of the beads it is very important that the washing of the 
beads be complete to remove all serum and reagent and all unbound antigen 
and antibody. Further, it is extremely important that the washing step be 
accomplished without leakage or uncontrolled escape of the virus 
containing serum. 
Previously, the washing of serum from beads was accomplished by repeated 
rinsing of the beads. That is, the washing fluid was poured over the bead 
and then rinsed from the receptacle containing the bead. When using this 
method it is difficult to remove all of the washing fluid such that a 
small amount of contaminated serum remains after each washing step. 
Therefore, although diluted by each subsequent washing, a small amount of 
the contaminated serum may remain even after repeated washings. Because 
removal of all the contaminated serum is important, this washing procedure 
has been less than satisfactory. An additional problem resulting from this 
procedure is that possible contamination due to spillage, splashing, or 
aerosolization of the washing substance may occur. This may present a 
danger to testing personnel and may contaminate associated apparatus. 
In order to speed up the washing process, mechanical washing devices have 
been used. Devices presently marketed by Abbott Laboratories Inc. under 
the trademarks of UNIWASH and PENTAWASH and described in U.S. Pat. No. 
3,949,771 use a wash probe which is lowered into the reaction tray well 
until the probe tip touches the bead and the tip is as far as possible 
into the well. An integral spray device is activated such that the washing 
substance is sprayed onto the sides of the well. A vacuum tube is 
positioned on the probe above the bead contact point such that the bead is 
retained against the device by the vacuum. While suited for its intended 
purpose, the device does not draw the washing substance over the entire 
surface of the bead. That is, the contacted areas of the bead are not 
sufficiently washed to remove all of the contaminated serum. The proximity 
of the bead to the well hinders the circulation of the washing substance 
around the bottom of the bead. In addition, no provision is made for 
preventing contaminated washing substance from escaping the well as by 
splashing and spillage. 
Another device, illustrated in U.S. Pat. No. 4,053,284 issued to N. A. 
Posch on Oct. 11, 1977, seals the well to prevent escape of contaminated 
serum from the well. This device uses a probe which is inserted into the 
well and which employs a stopper like device around its upper portion. The 
device is inserted into the well such that the washing portion extends 
into the well and the stopper seals the well from the outside atmosphere. 
The beads to be washed are contained in a reaction area at the bottom of 
the well. The reaction area is screened from the rest of the well such 
that the beads are prevented from moving to other parts of the well. The 
centermost portion at the bottom of the well is vacant such that the 
vacuum tube attached to the wash probe may extend near the bottom of the 
well. The washing fluid is drawn into the well by the vacuum through ports 
in the washing probe. The washing fluid then flows down the side of the 
well and over the beads. The fluid collects at the center of the well and 
is drawn up through the vacuum tube. While suited for its intended 
purpose, the beads are confined in the cleaning area by the screens and 
touch both each other and the walls of the well. As such, the entire 
surface of the beads may not be washed thereby allowing some contaminated 
hepatitis serum to remain on the beads. A single larger bead may be washed 
with this device in the same manner as the smaller beads. That is, the 
single large bead is washed by the same method except that no screening is 
necessary to keep the bead from being drawn up through the vacuum tube. 
Instead, the bead is positioned between the vacuum tube and the wall of 
the well. The bead thus contacts both the well and the side of the vacuum 
tube thereby hindering the circulation of the washing fluid and resulting 
in incomplete washing of the contacting surfaces. 
It would be desirable to have an irrigating device in which the object may 
be moved by or suspended in the cleaning fluid in order that all surfaces 
of the object may be contacted by the fluid. 
SUMMARY OF THE INVENTION 
The invention is a method and device for washing an object within a 
receptacle. The object is substantially sealed within the receptacle. The 
object is washed such that it is movable between the device and the 
receptacle thus allowing the washing fluid to contact all surfaces of the 
object. The flow around the object is thus enhanced resulting in complete 
washing of the object. 
An end portion of the device is introducible into and cooperative with the 
receptacle thereby defining a substantially enclosed space containing the 
object. The end portion includes a tip surface adjacent the object. A 
means for introducing a fluid into the substantially enclosed space is 
positioned adjacent the end portion. A means for aspirating the fluid from 
the substantially enclosed space is contiguous with the tip surface. The 
object is positioned between the aspirating means and the receptacle, 
being spaced from the aspirating means, and it is movable therebetween by 
the aspiration of the fluid. 
In the preferred embodiment the device includes at least one high velocity 
nozzle mounted adjacent the tip surface. The aspirating means includes a 
vacuum tube extending beyond the tip surface. The portion of the vacuum 
tube extending beyond the tip surface is slotted to allow aspiration of 
the fluid even though the object may be adjacent the vacuum tube opening. 
The tip surface is configured to approximate a mating surface for at least 
part of the surface of the object to be washed. The end portion includes a 
shoulder which contacts a ridge on the receptacle. As such, the 
substantially enclosed space is sealed such that contaminated serum is 
prevented from escaping either by spillage or by aerosolization. The 
preferred embodiment of the device is used to wash coated beads which are 
spherical in shape. The tip surface is thus shaped concavely to allow the 
spherical bead to be drawn up adjacent the vacuum tube. The concave shape 
also improves the flow pattern over the spherical object.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
Like reference numerals denote like structure throughout each of the 
various figures. Referring to FIG. 1, the device generally indicated as 11 
is used by an operator 12. An inlet hose 13 and an outlet hose 14 
respectively introduce and remove the washing fluid from the device. A 
handle case 15 and an exhaust control 16 are held by operator 12. A 
plurality of tubes 17 are connected to handle 15. Each of tubes 17 contact 
a ridge 18 on each of a plurality of wells 19. 
Referring to FIG. 2, a sectional view of the device is illustrated. Inlet 
hose 13 and outlet hose 14 are connected to handle 15 and communicate with 
an inlet passage 22 and an outlet passage 23, respectively. Inlet passage 
22 communicates with inlet hose 13 through a connector 21 and with an 
inlet tube 24 contained within each of the tubes 17. Outlet passage 23 
communicates with an aspirating means which may include a vacuum tube 25 
within each of tubes 17. In the preferred embodiment vacuum tube 25 and 
inlet tube 24 are concentrically mounted with tube 17. For purposes of 
illustration, only one tube 17 is shown in detail in FIG. 2. Each of tubes 
17 terminate in a tip surface 26. In the preferred embodiment tip surface 
26 is concavely shaped so as to mate with a spherical object. A means for 
preventing the object from contacting vacuum tube 25 includes a slotted 
extension 27. Slotted extension 27 extends beyond tip surface 26 and 
toward the object (not shown). 
Referring again to FIG. 2, an introducing means which may include a 
plurality of high velocity nozzles 28 connect to inlet tubes 24 and allow 
the washing fluid to be introduced into the enclosed space defined by tube 
17 and well 19 (shown in FIG. 1). A shoulder 29 on tube 17 substantially 
seals to ridge 18 (shown in FIG. 1) to define the substantially enclosed 
space within well 19. An end portion 31 of tube 17 is defined between 
shoulder 29 and tip surface 26. A means for regulating the introducing of 
the washing fluid comprises a ball 32 and a spring 33 in inlet passage 22. 
An exhaust valve comprising a plug 34 and a spring 35 communicates with 
outlet passage 23 and is activated by trigger 16. 
Referring to FIG. 3, tube 17 and well 19 are shown in partial sectional 
view. Shoulder 29 on tube 17 cooperates with ridge 18 on well 19 to define 
substantially enclosed space 35. End portion 31 terminates in tip surface 
26. Vacuum tube 25 terminates in extension 27. Inlet tube 24 communicates 
with high velocity nozzles 28 which in turn communicate with substantially 
enclosed space 35. An object 36 is contained within substantially enclosed 
space 35. Object 36 is positioned between tip surface 26 and the bottom of 
well 19. 
Referring to FIG. 4, end portion 31 is shown in sectional view to 
illustrate the aspiration of the substance. Shoulder 29 on tube 17 mates 
with ridge 18 on well 19. End portion 31 extends into well 19. Vacuum tube 
25 terminates in extension 27 which protrudes beyond tip surface 26. High 
velocity nozzles 28 communicate with substantially enclosed space 35 on 
one end and with inlet tube 24 at the other end. Object 36 is contained 
within substantially enclosed space 35. 
MODE OF OPERATION 
Referring to FIGS. 1 and 2, the washing device is used to wash well 19 and 
an object or objects contained therein. Operator 12 controls the flow of 
the washing fluid through the device by the use of trigger 16. Referring 
to FIG. 2, trigger 16 contacts spring loaded plug 34. Plug 34 is biased in 
the open position by spring 35. By depressing trigger 16, plug 34 is moved 
downward thereby blocking outlet passage 23. A vacuum source (not shown) 
connected to tube 14 is thus cut off from outlet passage 23 thereby 
eliminating the vacuum in outlet passage 23 and vacuum tube 25. The flow 
of washing fluid from the device through tube 13 is controlled by a check 
valve which includes ball 32 and spring 33. Ball 32 is held against 
connector 21 by spring 33 thus preventing the flow of washing fluid from 
the device. When plug 34 is in the up position, that is, when trigger 16 
is not depressed, the vacuum created in the device through tube 14 is 
sufficient to draw the washing fluid into the device by overcoming the 
biasing force provided by spring 33 allowing ball 32 to be pushed away 
from connector 21. When the trigger 16 is depressed, the vacuum is cut off 
and spring 33 again biases ball 32 against connector 21 thereby cutting 
off the flow of the washing fluid to the device. The check valve also 
prevents the siphoning of the washing fluid from wells 19. Operator 12 is 
thus able to control both the input and output of the washing fluid to and 
from the device. 
Referring to FIG. 2, the washing fluid is introduced through inlet tube 13 
and into inlet passage 22. The fluid is then conveyed down inlet tube 24 
and out of high velocity nozzles 28 into wells 19. Although, for ease of 
illustration, only one tube 17 is shown in FIG. 2, it should be understood 
that a plurality of tubes 17 may be included on the device. The washing 
fluid, after being injected into well 19 by nozzle 28, is aspirated 
through extension 27 and up vacuum tube 25 to outlet passage 23. The fluid 
is then evacuated from the device through outlet tube 14. 
Referring to FIG. 3, tube 17 is shown along with a well 19 in partial 
sectional view. End portion 31 is inserted into well 19 such that shoulder 
29 mates with ridge 18 on well 19 substantially sealing the inside of well 
19 and thereby defining a substantially enclosed space 35 within well 19. 
The leakage of any washing fluid from well 19 is thus prevented. In 
addition, if the device is used for cleaning purposes as during hepatitis 
virus testing or the like, any contamination due to leakage or 
aerosolization of the washing fluid or other substances within well 19 is 
prevented. For hepatitis testing a glass or plastic bead may be used as 
object 36. Object 36 is contained within substantially enclosed space 35. 
Tip surface 26 is configured to approximate a spherical surface such that 
at least a part of a spherical bead may be received therein. The tip 
surface configuration improves the flow pattern of the washing fluid 
around the spherical object. 
Referring to FIG. 4, end portion 31 is shown in sectional view to 
illustrate the operation of the device. Specifically, the washing fluid is 
drawn through inlet tube 24 and high velocity nozzles 28 and injected into 
substantially enclosed space 35. The flow of the washing fluid moves 
object 36 away from the bottom of well 19. That is, the washing fluid is 
injected into substantially enclosed space 35 and is exhausted through 
vacuum tube 25 such that the flow of the fluid around object 36 causes 
object 36 to be moved upward adjacent tip surface 26. Object 36 is thus 
suspended in and contacted on all surfaces by the washing fluid. Greater 
rinsing action is thus achieved. Extension 27 protrudes beyond tip surface 
26 such that it prevents object 36 from sealing off vacuum tube 25 if the 
object is drawn up that far. That is, extension 27 is slotted such that 
contact by object 36 will not prevent the aspiration of the fluid from 
substantially enclosed space 35. The contact area of extension 27 is small 
enough so as not to prevent the washing of any surface area on object 36. 
When the vacuum is shut off as by the depressing of trigger 16 by the 
operator 12, then object 36 drops back onto well 19. 
The curvature of tip surface 26 along with the action of the washing fluid 
when introduced into substantially enclosed space 35 results in a flow 
pattern for the fluid which carries the fluid around all surfaces of 
object 36. A better rinsing action may be thus achieved. This is 
especially important if the device is used in hepatitis virus testing 
because it is important to remove all of the serum from the glass bead. In 
prior devices the glass bead contacted either the well or the washing 
device or both. Because not all of the bead surface was exposed, 
incomplete washing resulted. With the present invention all surfaces of 
the bead are contacted by the washing fluid and thus all traces of serum 
may be removed from the bead. 
Another advantage of the present invention is that it may be autoclaved. 
That is, the device is designed such that exposure to high temperature 
steam will not adversely affect its performance. The check valve defined 
by ball 32 and spring 33 and the exhaust valve defined by plug 34 and 
spring 35 are simple in construction and operation. The valves will not 
freeze up after autoclaving. The rest of the device is also constructed of 
materials which will not be affected adversely by exposure to high 
temperature steam. Because the device may be autoclaved, the possibility 
of contamination to an operator is reduced. This is especially important 
when the device is used during testing for highly contageous viruses such 
as hepatitis. 
While a particular form of the invention has been described with respect to 
a particular embodiment thereof, it is not to be so limited as changes and 
modifications may be made therein which are within the full intended scope 
of the invention as defined by the appended claims. For example, while the 
invention has been illustrated for use with a spherical object 36, it is 
possible that other objects of a different shape may be washed by the 
device. Modifications to the substantially concave tip surface 26 such 
that the tip surface 26 is capable of receiving a portion of a different 
shaped object would be required. Additionally, while one tube 17 has been 
described and five tubes 17 have been illustrated in FIG. 1, it is to be 
expressly understood that any number of tubes 17 may be utilized without 
departing from the scope of the invention. For instance, it may be desired 
to have only one tube to wash each well individually. Alternatively, it 
may be desired to wash a row of wells as is illustrated in FIG. 1. It 
would also be within the scope of the invention to utilize a device which 
washes all of the wells at once. That is, tube 17 need not be in a single 
row. The use of testing trays having well placement other than that 
illustrated in FIG. 1 may necessitate different placement or numbers of 
tubes 17. 
Other contemplated uses of the invention include its use as a coating 
device. That is, the substance to be introduced could be of a nature so as 
the bond to the object. Excess coating substance may be aspirated from the 
well. The unique advantages of the invention would assure even coating on 
all surfaces of the object. While the washing fluid is contemplated as a 
liquid it is to be expressly understood that a powder, gas, etc. may be 
utilized with the device without departing from the scope of the 
invention. 
The foregoing description, taken together with the appended claims, 
constitutes a disclosure which enables one skilled in the art and having 
the benefit of the teachings contained therein to make and use the 
invention. Further, the structure herein described constitutes a 
meritorious advance in the art which is unobvious to such skilled workers 
not having the benefit of these teachings.