Animal marker implanting system

A system for implanting a solid marker in an animal is provided. The apparatus includes a hollow tube having an entrance and an exit opening. A support is provided for supporting a hollow tube. A plunger is slideably disposed between a first position and a second position within the support. The plunger cooperates with the support and the tube. The plunger engages the marker proximate to the entrance opening of the tube, and ejects the marker through the tube when the plunger is moved from a first position to a second position.

BACKGROUND OF THE INVENTION 
This invention relates, in general, to a system for implanting an 
identification marker in an animal and, in particular, to a system for 
facilitating implantation and retention of an identification marker into a 
laboratory animal. 
Heretofore, the marking of animals for tracking and testing purposes has 
involved marking the animal externally, i.e., tatooing, branding or 
tagging. These external markers are difficult to read when identifying the 
animal and are extremely limited in the amount of information about the 
animal that can be carried by the external marker. 
In order to overcome the disadvantages noted above with external markers, a 
system has been proposed whereby markers carrying information that can be 
read by an external detector can be implanted in a test animal. However, 
such a system requires an instrument that permits a marker to be delivered 
into the animal without difficulty and wherein the marker will remain 
securely embedded in the lab animal for a considerable length of time. 
SUMMARY OF THE INVENTION 
Generally speaking, in accordance with the invention, an improved apparatus 
for implanting a marker into an animal is provided. The apparatus includes 
a hollow tube having an opening at each end. An entrance end of the hollow 
tube is supported within a housing. An exit end of the tube is sharp to 
allow subcutaneous penetration of the tube underneath the skin of a 
laboratory animal. A plunger is slideably mounted within the housing. The 
plunger is adapted to displace the marker from a first position in the 
tube out of the exit end of the tube. 
In an exemplary embodiment, an electronic transponder containing 
information about the animal, such as identification numbers, is placed in 
the marker. When the tube is inserted below the skin of the animal and the 
plunger is displaced, the marker containing the electronic transponder is 
forced through the tube, lodging it underneath the skin of the animal. 
An object of this invention is to provide an improved apparatus for 
implanting markers in laboratory animals. 
A further object of this invention is to provide an implanting system for 
facilitating identification of laboratory animals. 
Still a further object of this invention is to provide an easy to use 
implanting instrument for implanting a marker into a laboratory animal. 
Yet a further object of the invention is to provide an implanting system 
for implanting a marker subcutaneously in the animal so that the marker 
will be retained within the animal. 
Still other objects and advantages of the invention will in part be obvious 
and will in part be apparent from the specification and the drawings. 
The invention accordingly comprises features of construction, combination 
of elements and arrangements of parts which will be exemplified in the 
construction hereinafter set forth and the scope of the invention will be 
indicated in the claims.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Reference is initially made to FIGS. 1 through 15, wherein an animal 
marking system including an implanting instrument, generally indicated at 
10 (FIG. 1), a needle assembly, generally indicated as 19 (FIG. 13) and an 
animal marker, generally indicated as 30 (FIGS. 11, 12 and 14) is 
depicted. As is explained in greater detail below, the cooperation of the 
needle assembly, marker and implanting instrument permits the facile 
implantation of a marker into a laboratory animal and the retention of the 
marker within the animal during long periods of laboratory monitoring and 
testing. 
Reference is now particularly made to FIGS. 1 through 5, wherein instrument 
10 is illustrated in detail. Instrument 10 defines two opposed half walls 
27 which are molded in mirror image and secured together to define a 
unitary housing in the shape of a handle 31. Each opposed wall 27 is 
defined by a substantially parallelogram shaped configuration including 
lengthwise mating walls 27a and lateral mating walls 27b and 27c. As is 
explained in greater detail below, mating walls 27a are inclined with 
respect to lateral mating walls 27b to define handle 31 and to facilitate 
storage therein of a plurality of needle assemblies. A cap 34 is slideably 
mounted to the housing defined in opposed wall 27. In an exemplary 
embodiment, at least one of the opposed walls 27 can be transparent or 
translucent to allow the user to view the needle assemblies 19 disposed 
within the handle. 
Cap 34 is normally disposed in a closed position, and can be displaced in 
the direction A (FIG. 2) from a closed position (solid lines in FIG. 2) to 
an open position (phantom lines in FIG. 2). As is illustrated in FIG. 7, 
cap 34 includes side walls 34a and gripping walls 34b which are disposed 
in elongated slots 27' formed in opposed walls 27. Cap 34 includes ribs 35 
on the side for permitting the cap to be easily gripped and can be 
displaced between an open and closed position. An arrow 37 or other 
indicia can be imprinted on cap 34 to indicate the proper directions for 
sliding. 
Opposed lateral walls 27b are covered by cap 34 when cap 34 is in a closed 
position. Opposed lateral walls 27b are configured to define opposed 
recessed walls 38a and an open chamber, generally indicated at 38, for 
receiving a needle assembly and for permitting each needle assembly to be 
dispensed through the opening from the interior of the housing when cap 34 
is displaced to an open position. Opposed lateral walls 27b are further 
configured to define a channel 39 which orients the needle assembly when 
it is positioned in chamber 38. 
Referring particularly to FIGS. 10 through 15, needle assembly 19 is formed 
from a stainless steel hollow tube 20 having an exit opening 21 and an 
entrance opening 23. Exit opening 21 is formed in the shape of an inclined 
edge 22 which forms a sharp point for permitting the tube to easily 
penetrate an animal's skin. The side of tube 20 having entrance opening 23 
is molded in a plug 24. Plug 24 includes a sleeve 25 integrally formed 
therewith and projecting about tube 20 to extend along a portion of the 
tube's length. Plug 24 includes arcuate end walls 24a for facilitating the 
positioning of the plugs in chamber 38 in a manner that will be discussed 
in detail below. As is particularly illustrated in FIG. 15, marker 30 is 
positioned in tube 20 near the exit opening 21 thereof. A drive pin 16 is 
used to position the marker within the tube. Drive pin 16 includes a 
sealing disc 17 that is integrally molded therewith. Sealing disc 17 has 
an outside diameter that is sufficient to interference fit with the inside 
diameter of the tube 20 and prevent displacement of the drive pin during 
normal stoage and handling of the needle assembly. Drive pin 16 aids in 
positioning the marker in the tube. However, it has been found necessary 
to facilitate positioning of the marker in tube 20 particularly when the 
marker is a glass capsule in order to prevent the marker from slipping out 
of the exit opening of the tube. 
Reference is now made to FIGS. 11 and 12 wherein a projection 29 integral 
with sleeve 25 extends through opening 28 in order to prevent the marker 
from slipping or moving in the tube prior to the discharge of same into 
the animal. This projection can be easily formed during assembly of the 
hollow tube within plug 24 by molding the plug about the tube and 
permitting the resin used to form the tube to enter aperture 28. 
Projection 29 is intended to frictionally engage marker 30 when the marker 
is positioned within tube 20 to prevent the marker from sliding in the 
tube. Projection 29 will hold the marker in place until a force sufficient 
to push marker 30 through tube 20 is applied to a plunger and, in turn, to 
the marker. 
In an exemplary embodiment, tube 20 is stainless steel. However, tube 20 
may be made from other rigid FDA approved materials, such as Ultem.RTM., 
manufactured by General Electric. Also, as aforenoted, sleeve 25 and plug 
24 can be integrally formed by injection molding a plastic resin about the 
entrance opening of tube 20. Also, the sleeve and plug may be formed of 
rigid materials other than plastic. 
Needle assembly 19 is easily positioned in chamber 38 when cap 34 is 
displaced into an open position. Moreover, needle assembly 19 is tightly 
secured within chamber 38 by returning cap 34 to a closed position. This 
prevents any wobbling of the needle 19 assembly during use. 
Plunger 18 includes a rod 41 and a knurled surface 43 integrally formed at 
one end of rod 41. Plunger 18 is slideably mounted within elongated 
channel 39 formed by lateral walls 27b formed in the top of the housing. 
Knurled surface 43 projects through elongated opening 44 in cap 34 and 
permits the plunger to be displaced between a start position and an 
implanting position. Channel 39 is coaxially aligned with the entrance 
opening 23 of tube 20 of the needle assembly 19 and alignment channel 49 
to form a continuous pathway for rod 41 when needle assembly 19 is 
retained in chamber 38. Knurled surface 43 extends through elongated 
opening 44 (FIG. 9) in cap 34, allowing displacement of the plunger 18 by 
pushing knurled surface 43 from a start position to an implanting 
position. Plunger 18 also includes seats 18a projecting therefrom which 
rests against stops 27e formed by opposed half walls 27. Stops 27e and 
seats 18a cooperate to normally maintain the plunger at the start position 
depicted in FIG. 6. 
The distance of the placement of the marker in the tube from the exit 
opening and the length of elongated opening 44 have relative lengths with 
respect to each other. When cap 34 is displaced in the direction A into an 
open position, it will capture knurled surface 43 if it is not already in 
a start position and displace the plunger to a start position so that rod 
41 is entirely displaced outside of the entrance opening 23 of the needle 
assembly 19. Furthermore, the distance of the placement of the marker from 
the exit opening determines the distance through which the rod will be 
displaced and, hence, the preferred distance of elongaged opening 44. 
Moreover, this distance further assumes that rod 41 is entirely displaced 
without the entrance opening of the tube when plunger 18 is in a start 
position. This permits placement of needle assembly 19 in chamber 38. 
When cap 34 is returned to a closed position, stop 27e helps maintain 
plunger 18 at its start position so that the plunger is not 
unintentionally pushed forward. If slideable cap 34 is not pushed entirely 
into a closed position, knurled surface 43 is prevented from being pushed 
forward sufficiently to cause plunger 18 to eject the marker 28 from the 
needle assembly 19. This configuration prevents use of the instrument 
unless the needle assembly 19 is fully secured within chamber 38 and is 
securely captured by cap 34 being displaced into a closed position. Also, 
since knurled surface 43 of the plunger 18 comes in contact with the cap 
at the limits of elongated opening 44, the plunger 18 is automatically 
positioned by manipulating the cap. 
Reference is now also made to FIG. 8, wherein operation of the instant 
invention is depicted. In an exemplary embodiment, marker 30 is stored 
within tube 20 and is retained therein by a projection 25. Cap 34 is then 
slid into an open position. Needle assembly 19 is then pivotably displaced 
into chamber 38. Cap 34 is then displaced forward into a closed position 
supporting and anchoring needle assembly 19 securely in place within 
chamber 38 and channel 49. 
Next, a test animal, such as a mouse 46, must be stabilized. As illustrated 
in FIG. 8, a mouse can be picked up in the user's one hand and the 
implanting instrument held in the user's other hand. However, as is 
illustrated in FIG. 16, in an exemplary embodiment, a cylinder 80 that is 
open at both ends can be utilized to render the head of the mouse 
immobile. By inserting the mouse's head in a cylinder the mouse cannot 
turn its head and bite the user's hand or otherwise interfere with the 
procedure. Furthermore, once the mouse's head is immobilized in the 
cylinder it permits the hand of the user to be used to stretch the 
animal's skin and thereby facilitate manipulation of the mouse during 
subcutaneous implantation. Accordingly, the implanter systems of the 
instant invention contemplates the use of different sized tubes to 
accommodate the distinct differences in the size of the laboratory 
animals. Once the animal is immobilized, the user is prepared to insert 
tube 20 into the laboratory animal. 
Exit end 21 of tube 20 is inserted subcutaneously into mouse 46 until the 
animal's skin 48 reaches the edge of sleeve 25. This automatically places 
marker 30 at the desired position beneath the skin. Knurled surface 43 of 
the plunger 18 is then pushed forward, preferably with the user's thumb 
50, with enough force such that plunger 18 engages drive pin 16. Knurled 
surface 43 is displaced until knurled surface 43 is disposed into an 
implanting position so that rod 43 comes in contact with the end of 
opening 44 in cap 34. At this point, plunger rod 41 of plunger 18 has 
engaged drive pin 16 and extends far enough within tube 20 to have forced 
drive pin 16 to eject marker 30 from tube 20 underneath the animal's skin. 
Next, the implanting apparatus is removed from animal skin 48, cap 34 is 
pulled back and needle assembly 19 is removed and discarded. The process 
may then be repeated for another animal. 
In an exemplary embodiment, marker 30 is a glass capsule having therein an 
electronic transponder containing identification information about the 
animal. This is used by way of example only. This process is adaptable to 
the implantation of any type of marker. Marker 30 is formed by embedding 
an electronic transponder (not shown) in a glass capsule. By using an 
electronic transponder, the amount of storable information is greatly 
increased, especially when transponder information can be directly linked 
to computer systems containing further information and processing 
software. Because the capsule is glass, it tends to slide easily in 
stainless tube 20. It is for this reason that projection 29 is used to 
interference fit the capsule in the tube and prevent same from moving 
within the tube during storage and handling of the needle assembly. 
Each needle assembly 19 is sealed within a sanitary sleeve 33 which can be 
easily removed when the needle assembly is displaced into chamber 38 for 
use in the manner described above. Moreover, after sanitary sleeve 33 is 
used to cover the exit opening of the tube, a sterilant gas can be 
injected into a chamber defined by tube 20, drive pin 16 and sealing disc 
17 and the sleeve 33. By introducing a sterliant gas, the marker can be 
sterilized and remain sterilized until the needle assembly is ready for 
use. Furthermore, as is illustrated particularly in FIGS. 2 through 5 and 
13, the opposed side walls 27 of the housing and the plug 24 of each 
needle assembly are configured in a manner discussed below to permit each 
needle assembly to be stored in the handle and removed therefrom for easy 
use. 
Specifically, a pair of opposed ramps 45 are formed in each wall 27. Ramps 
45 are formed in mirror image on each wall so that they are disposed in 
registry with each other when walls 27 are brought together to form the 
housing defining handle 31. Furthermore, each ramp is disposed in parallel 
with lateral wall 37c and at an angle with respect to the lengthwise 
extent of the handle. Ramps 45 are spread a sufficient distance apart to 
permit two rows of needle assemblies to be stored in the handle. 
The plug of each needle assembly includes positioning grooves 26 found in 
opposed surfaces, the grooves being disposed on an angle with respect to 
the lengthwise extent of the plug and diagonally opposed with each other 
to facilitate placement of each needle assembly in the housing during 
assembly of the product. As is illustrated with some particularity in 
FIGS. 3 through 5, each needle assembly can be positioned within handle by 
racking the plug onto a first ramp 45 so that the ramp is positioned 
within the positioning groove 26. The groove 26 and ramp 45 prevent any 
substantial lengthwise displacement of each needle assembly during storage 
and use of the instrument. The opposing ramp assists in positioning the 
plug by pressing against the plug. Each ramp 45 includes a positioning 
ramp 45a that is parallel with the lengthwise side walls 27a of handle 31. 
Positioning ramp 45a does not protrude as far as ramp 45 and is provided 
to assist in preventing the plug from sliding laterally and to further 
assist in guiding the needle assembly through the opening in chamber 38 
when a needle assembly is to be removed from the handle. 
In an exemplary embodiment, ten needle assemblies are stored on each ramp 
45. As noted above, wall 27a and ramp 45a facilitate delivery of each 
needle assembly to the operator. 
As is illustrated in FIG. 2, the opening in chamber 38 is sufficiently 
large to permit the needle assembly to be removed therethrough. 
Accordingly, when a needle assembly is needed, cap 34 is displaced from a 
closed position to an open position. By manipulating the orientation of 
the housing, a needle assembly positioned closest to chamber 38 will then 
slide out of the housing through opening 38. As aforenoted, such 
manipulation can be facilitated by forming one of the opposed walls 27 
forming handle 31 out of a transparent or translucent material. It is then 
a simple matter to position plug 24 of the needle assembly in chamber 38, 
slide cap 34 to a closed position and remove the sanitary sleeve 33, so 
that the user is ready to begin implantation of the marker in the manner 
discussed above. 
Reference is now made to FIG. 14, wherein a marker 30 is formed of a smooth 
material 81, such as glass. As aforenoted, the use of a glass marker can 
be problematical. First, when the needle assembly does not include a 
projection 29, marker 30 is not secured in the tube and, hence, the marker 
may slide out of the tube of the needle assembly. Also, it has been 
observed that when a glass encapsulated transponder is implanted in a 
laboratory animal, migration of the transponder out of the wound of the 
animal can occur. Accordingly, in a preferred embodiment, one-half of 
marker 30 is coated with a layer 83 having a high coefficient of friction. 
For example, Silastic.RTM., manufactured by Dow Corning, has been 
successfully used. Also, polypropylene has been used as a coating. By 
utilizing a layer coating marker 30, projection 29 can be eliminated, 
thereby allowing for a thinner tube 20 having a greater inner diameter 
than the embodiments containing projection 29. 
The instant invention further contemplates a method of forming layer 38 
about a glass marker. Specifically, markers are partially inserted into a 
mold cavity. Thereafter, a polypropylene resin is injected into the mold 
cavities and cured about the marker to define a suitable non-slippery 
surface. 
In a further embodiment, the outer surface of glass of marker 30 can be 
etched. Although etching of the outer glass coating prevents migration in 
the animal, projection 29 is still needed to hold marker 30 in place in 
the tube 20. However, etching has been found to weaken the marker and 
although experimentally viable, does not appear to offer the same 
efficiency as the use of a coating on the glass capsule. 
Reference is now made to FIGS. 17, 18 and 19 wherein an alternate 
embodiment of the implanting apparatus of the instant invention is 
depicted. Again, the implanting apparatus includes a needle assembly 52, a 
housing, generally indicated at 57, and a plunger mechanism, generally 
indicated as 63. 
Housing 57 includes an elongated member 61 having finger retainers 58 
integrally projecting therefrom on its opposed sides to prevent rotation 
of the implanting apparatus during use. Ribs 59 are formed on elongated 
member 61 opposite retainers 58 to prevent slipping of the fingers, and to 
give added grip while using the apparatus. A stop 62 is formed at the rear 
of housing 57 for limiting the displacement of the plunger mechanism. 
Needle 52 is fixedly supported within housing 57 and is formed from a 
hollow tube 53 having an exit opening 54 and an entrance opening 55. Exit 
opening 54 is characterized by an inclined edge opening 56 which defines a 
pointed surface. Edge 56 permits easy subcutaneous insertion of the 
implanting apparatus. 
Plunger mechanism 63 includes a rod 68 and a knurled surface 69 integrally 
formed at one end of rod 68. Plunger mechanism 63 is slideably mounted in 
an elongated bored opening 60 within housing 57. Elongated bored opening 
60 is axially aligned with and forms a continuous pathway with hollow tube 
53. Plunger mechanism 63 is slidably disposed in housing 57 and is 
displaced by pushing on knurled surface 69 in a direction toward exit 
opening 56 in tube 53. A channel 67 is formed within the top of elongated 
member 61 and extends from stop 62 to retainers 58. This allows the 
passage of knurled end 69 past stop 62. When knurled end 69 is displaced 
forward and comes in contact with the retaining end of the channel, rod 68 
extends into needle 52. This causes a marker 70, displaced in the pathway 
of plunger 63 to be ejected through the exit opening of tube 53. 
A marker cartridge assembly, generally indicated as 64, includes a circular 
hub member 72, and a plurality of marker holders 73 projecting from 
circular hub member 72. Holders 73 are equally spaced about circular hub 
member 72. Each holder 73 has a depth that is longer than the length of 
marker 70. Marker 70 is held within a bore 74 which opens at each end. 
Bore 74 is sized to interference fit snugly about marker 70 so that a 
force is needed to push marker 70 loose from bore 74. Each holder 73 of 
marker cartridge 64 is sized to fit within a chamber 77 formed in 
elongated member 61. Chamber 77 is axially positioned between tube 53 and 
elongated opening 60. Chamber 77 is sized to received and retain holder 73 
in place within housing 57, and also permits holder 73 to be released when 
sufficient force is applied to marker cartridge assembly 64. A rib 78 is 
located on each side of chamber 77 and is positioned in parallel with 
plunger 63 to assist in securing holder 73 within chamber 77. When in 
place, bore 74 of holder 73 is axially aligned with plunger 63. 
In operation, plunger 63 is displaced to a loading position such that 
knurled surface 69 is disposed beyond stop 62 and rod 68 is clear of 
channel 77. The marker cartridge assembly is removed from a sanitary 
transport package (not shown), and is releasably inserted into chamber 77. 
Each holder is individually sealed within a sanitary package (not shown) 
which is torn away when the holder 73 is displaced into chamber 77. As 
discussed above, in this position plunger mechanism 63, marker 70 
contained within holder 73, and needle 52 are all axially aligned. Knurled 
surface 69 of plunger mechanism 63 is then pushed forward until knurled 
surface 69 is aligned with stop 62. The length of rod 68 is selected so 
that it will engage marker 70 in the bore 74 of holder 73 and push marker 
70 into the entrance opening 55 of needle 52. Rod 68 is now disposed 
through bore 74. 
Marker cartridge assembly 64 is removed from chamber 77 to keep cartridge 
assembly 64 from interfering with proper use of the implanting apparatus 
when injection into the animal occurs. Rod 68 passes through slot 75 
allowing easy removal of marker cartridge assembly 64 from cavity 77. 
As described above, an animal 79 is then held in either hand, while the 
implanting apparatus is held in the other hand. Needle 52 is inserted into 
animal 79 and knurled surface 69 is pushed forward from the stop position 
to the implanting position so that knurled surface 69 comes into contact 
with the end of the channel 67 causing rod 68 to be disposed within tube 
53 and to eject marker 70 from needle 52 under the animal's skin. The 
needle 52 is then removed from beneath skin 80, cleaned and another holder 
73 having a new marker 70 is inserted into the chamber so that the process 
can be repeated for a different animal. 
It will thus be seen that the objects set forth above, and those made 
apparent from the preceding description, are efficiently attained and, 
since certain changes may be made in the above construction without 
departing from the spirit and scope of the invention, it is intended that 
all matter contained in the above description or shown in the accompanying 
drawings shall be interpreted as illustrative and not in a limiting sense. 
It is also to be understood that the following claims are intended to cap 
all of the generic and specific features of the invention herein 
described, and all statements of the scope of the invention which, as a 
matter of language, might be said to fall therebetween.