Microtool mount

Details Microtool mount Microtool mount

2000-06-19

2002-03-19

Ramirez, Ramon O. (Department: 3632)

Supports

Article carried

Mounted by clamping means

C248S309400

Reexamination Certificate

active

06357719

ABSTRACT:

FIELD OF THE INVENTION
This document corcerns as invention relating generally to mounting/gripping apparata for use in the handling and manipulation of microtools (i.e., precision instruments and manipulators for microtechnology and nanotechnology applications, such as fluid-transporting microcapillaries), and more specifically to mounting apparata for quickly and safely receiving and releasing fragile microcapillaries.
BACKGROUND OF THE INVENTION
Capillaries are commonly used in biological applications to sample and transport fluids and/or cells for testing or other purposes. When particularly fine biological microoperations are required—for example, injecting or removing cellular genetic material during in vitro fertilization or cloning operations—microcapillaries are generally used. Microcapillaries are ordinarily prepared by taking a standard glass capillary tube (usually having 1 millimeter diameter), and heating it until it becomes ductile. The capillary is then stretched, causing its diameter to contract. When the capillary is stretched to the desired diameter, generally around 10 microns (inner diameter), it is cooled and allowed to set. The microcapillary's leading edge may then be ground to a point by use of a microgrinder so that it has a sharp leading edge suitable for puncturing a cell membrane.
The microcapillary may then be inserted into the cell, and by decreasing the pressure at the end of the microcapillary, the desired cellular material may be aspirated into the microcapillary. Naturally, such an operation requires very precise control over the positioning of the microcapillary, and therefore mounting/positioning arrangements such as the one shown in
FIG. 1
are commonly used. Cellular material is placed on a sampling plate
10
(e.g., a Petri dish or the like). A microscope
12
(or other imaging apparatus) adjacent the sampling plate
10
allows viewing of cells as they are being manipulated. The microcapillary
50
is gripped with a mount
14
, with its tip
52
at or slightly above the sampling plate
10
. The mount
14
is mounted to an actuator
16
, which allows the mount
14
to reposition the microcapillary
50
in at least one dimension in relation to the sampling plate
10
by manipulating a joystick
18
or other input device. A flexible tube
54
fit over the end of the microcapillary
50
leads to a syringe
20
or similar injection device so that suction can be applied to the microcapillary
50
. Thus, a user may use the joystick
18
to position the microcapillary
50
as desired, and may use the syringe
20
to withdraw or inject cellular material from or to the cell(s) on the sampling plate
10
when the microcapillary
50
is appropriately positioned.
Problems can occur owing to the attachment between the microcapillary
50
and mount
14
, an arrangement which is shown in greater detail in FIG.
2
. In general, the mount
14
bears a V-groove
22
wherein the microcapillary
50
may be situated, and a screw-driven clamp
24
is adjusted to bear against the microcapillary
50
and hold it within the groove
22
. While this arrangement is simple to manufacture, operate, and maintain, it causes several significant difficulties with use of the microcapillary
50
.
First, it is exceedingly easy to either tighten the clamp
24
to such an extent that the microcapillary
50
is crushed, or to conversely leave the clamp
24
so loose that the microcapillary
50
slips within the groove. Breakage is highly inconvenient because the microcapillaries
50
take a long time to prepare, and are usually prepared right before an operation is to be performed to ensure that the microcapillaries
50
are uncontaminated with foreign matter. Since microcapillaries
50
are difficult to properly form and grind and it may take several tries before a suitable microcapillary
50
is obtained, lab personnel generally do not produce a large number of them; therefore, if the available microcapillaries
50
break, lab personnel may be set back by an hour or more as new ones are prepared. This delay may be costly since the cellular material to be operated on may have a limited time window of viability.
Second, the clamp
24
is somewhat time-consuming to deal with. As previously noted, the user must take care when placing a microcapillary
50
in the clamp
24
to be sure that the clamp
24
is neither too loose nor too tight. Further, it is desirable to have a microcapillary
50
which is at least generally well-positioned over the sampling plate
10
prior to the start of the operation: for example, it may be desirable to have it extend from the clamp
24
at or near a certain length, with its sharpened tip
52
being oriented at or near a desired angle. However, to reposition the microcapillary
50
within the clamp
24
, the clamp
24
must be unscrewed, the microcapillary
50
must be repositioned, and then the clamp
24
must be carefully screwed down again. These repositioning activities provide further opportunities for lost time and broken microcapillaries
50
.
Third, the mount
14
is difficult to use because the user must hold the microcapillary
50
in one hand and simultaneously tighten the clamp
24
. Because this is difficult to do with only two hands, the user often initially situates the clamp
24
in an improper position, and must then undergo the aforementioned iterative process of loosening the clamp
24
, adjusting the microcapillary
50
, and retightening the clamp
24
until the microcapillary
50
is properly positioned.
Since there is an increasing need for speedy and accurate operations on biological materials, particularly where the biological materials have time-limited viability, it would be advantageous to have available a microcapillary mount which overcomes the disadvantages of the prior mounts, and which allows for fast mounting, alignment, and release of microcapillaries, while minimizing the possibility of microcapillary breakage.
SUMMARY OF THE INVENTION
The invention, which is defined by the claims set forth at the end of this document, is directed to mounts for microtools (e.g., microcapillaries) which at least partially alleviate the aforementioned problems. A basic understanding of some of the preferred features of the invention can be attained from a review of the following brief summary of the invention, with more details being provided elsewhere in this document.
To summarize, the microtool mount (as best seen in the different embodiments of
FIGS. 3-5
) includes an elongated finger terminating in a tip. The finger has a pair of valley edges from which valley walls descend to terminate in a valley floor, thereby defining a valley between the valley walls and floor. The valley extends from the tip along a path parallel to at least a portion of the length of the finger. A microcapillary may be accommodated within the valley (see particularly FIGS.
3
and
4
), and a fastening member, preferably a magnet, may be removably affixed to the finger above the valley to maintain the microcapillary within the valley. The valley edges are preferably planar along at least a portion of the length of the finger so as to provide an even surface whereupon the magnet may be more firmly affixed to the finger. The valley is preferably situated within the finger so that a microcapillary resting therein will be aligned with the longitudinal axis of the finger, so that rotation of the finger about this longitudinal axis will also cause the microcapillary to rotate about its longitudinal axis. This allows for greater ease in positioning the microcapillary at desired locations during a biological operation.
In certain preferred embodiments (such as those of FIGS.
4
and
5
), at a location spaced rearward of the tip of the finger, one or more of the valley edges has a ledge from which the valley edge begins descending towards the valley floor. A gap is thereby defined in this valley edge and its valley wall. Such a gap may be defined in both valley edges/walls, as illustrated in
FIG. 4
, or the gap may be defined in one valley edge/wall, as

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