Microscope slide heater

[0002] 1. Field of the Invention

[0003] This invention relates generally to microscope slide stainers.

[0004] 2. Prior Art

[0005] Many types of biological specimens for microscopic examination are stained with color to increase contrast for better viewing. The process includes placing the specimen on a transparent microscope slide, applying a staining solution or reagent to the specimen, heating the specimen to a suitable temperature, and rinsing off the reagent. The staining process is very time consuming when done with separate equipment. Cross contamination between the slides occurs when they are transferred by hand from one piece of equipment to another, and also when the slides are stained by being submerged in the same reagent container.

[0006] Many mechanized slide stainers have been disclosed for automating the process. A stainer disclosed in U.S. Pat. No. 5,770,346 to Edwards includes a conveyer for automatically taking slides stored around a carousel and transporting them across several staining stations, including a heating station, and finally dropping them into a slide collection bin. A stainer disclosed in U.S. Pat. No. 4,738,824 to Takeuchi includes a robotic arm for dipping racks of slides in a plurality of baths. However, cross contamination occurs because the slides are submerged in the same baths. A stainer disclosed in U.S. Pat. No. 4,651,671 to Pedersen includes a plurality of pivoted robotic arms attached to a conveyer for dipping individual slides in a plurality of baths. Cross contamination also occurs because the slides are submerged in the same baths. A stainer disclosed in U.S. Pat. No. 4,413,584 to DiMaggio, Jr. et al. includes pivotable slide trays for tilting up the slides to assist runoff during rinsing. However, no heater is included. A stainer disclosed in U.S. Pat. No. 4,043,292 to Rogers et al. includes a carousel with radial arms for carrying slides to staining and heating stations. The arms are pivotable for tilting the slides. The slides are heated by being positioned on a heated platen. However, the wet slides will stick to the smooth top surface of the heated platen, so that they will be difficult to remove.

[0007] All fully automated slide stainers are complicated, and thus very expensive. They use large quantities of very expensive reagents. Many have transparent covers that allow radiated heat loss, which lengthens the warm up time. Many hold slides vertically, so that the slides cannot be observed during the staining process. Although some hold slides horizontally, they have darker or cluttered backgrounds that reduce contrast and hinder slide observation.

[0008] Accordingly, objects of the present microscope slide stainer are:

[0009] to stain-microscope slides;

[0010] to reduce human handling of the slides;

[0011] to heat the slides to selectable temperatures;

[0012] to start and stop heating very quickly;

[0013] to enable the slides to be seen clearly;

[0014] to prevent the slides from drying out;

[0015] to prevent the wet slides from sticking;

[0016] to tilt the slides to assist runoff during rinsing;

[0017] to prevent the runoff from each slide from crossing over onto adjacent slides; and

[0018] to prevent radiated heat loss for significantly faster warm up.

[0019] Further objects of the present invention will become apparent from a consideration of the drawings and ensuing description.

[0020] A microscope slide stainer includes a waste bin with an open top, and supporting notches arranged on the top edges of opposite sides. A slide supporting rack is supported in a horizontal position across the top of the bin in the supporting notches. The rack includes a pair of rails extending along a horizontal base. Brackets arranged on top of the rails define a plurality of spaced-apart slide holding positions. A hot plate is positioned between the rails and spaced above the horizontal base. A control box is attached to the hot plate for temperature control. Pins extending from opposite sides of the hot plate ride in direction-changing slots in the rails to enable the hot plate to be moved between a raised position engaged against the bottom of the slides, and a lowered position disengaged from the slides. Grooves are arranged on top surface of the hot plate to prevent the wet slides from sticking to it. A cover is removably positioned over the rack to define a heating and humidity chamber. The rack can be placed in a tilted position for rinsing the slides by inserting its ends in slanted slots extending downwardly from the supporting notches on the bin.

[0021] FIG. 1 is a side perspective view of the present microscope slide stainer with one slide supporting rack in position.

[0022] FIG. 2 is a top view of a hot plate of the slide stainer.

[0023] FIG. 3 is a side perspective view of the microscope slide stainer with both slide supporting racks in position and hot bars in a raised position.

[0024] FIG. 4 is a side perspective view of the microscope slide stainer with the slide supporting racks covered.

[0025] FIG. 5 is a side perspective view of the microscope slide stainer with the hot bar on one of the slide supporting racks in a lowered position.

[0026] FIG. 6 is a side perspective view of the microscope slide stainer with one of the slide supporting racks in a tilted position.

[0027] FIG. 1:

[0028] A preferred embodiment of the microscope slide stainer is shown in FIG. 1. It includes a waste collection bin 10 with an open top, and two pairs of supporting notches 11 and 12 arranged on opposite rims. A slide supporting rack 13 is supported in a horizontal position across the top of bin 10 by tabs 14 (one shown) at the ends of rack 13 positioned in notches 11. Rack 13 includes a pair of rails 15 extending along a horizontal base 16. Drainage slots 17 are arranged at the base of one of rails 15. A shoulder 18 is arranged around the perimeter on top of base 16. Brackets 19 arranged on top of rails 15 define a plurality of spaced-apart slide holding positions 20. Finger notches 21 are arranged at opposite ends of slide holding positions 20 between brackets 19. Much of rack 13 is preferably made of “CORIAN” by Dow Coming for resistance to acids, bases, stains, and heat.

[0029] An electrically activated, elongated hot plate 22 is movably positioned between rails 15 and spaced above horizontal base 16. Hot plate 22 is covered by a conventional heat resistant powder-coat white paint which is resistant to heat, stains, and chemicals. A control box 23 housing conventional electronics is connected to hot plate 22 for precise temperature control. Two pair of pins 24 and 25 (one of each pair shown) extending from opposite longitudinal edges of hot plate 22 respectively ride in direction-changing slots 26 and 27 in rails 15 to enable hot plate 22 to be moved between raised and lowered positions. Slots 26 and 27 each preferably include upper and lower horizontal sections connected by a slanted section. Slots 26 extend completely through rails 15, so that removable thumb-screw pins 24 extend through them. Slots 27 are preferably arranged only on the interior sides of rails 15, so that pins 25 do not extend through rails 15. The outer ends of slots 27 extend to the ends of rails 15, so that when thumb-screw pins 24 are unscrewed, hot plate 22 can be completely detached from rails 15 by sliding pins 25 out of slots 27. Grooves 28 are arranged on the top surface of hot plate 22 to provide air channels that prevent wet slides from sticking to it, and also to provide drainage for preventing liquid on the slides from flowing onto adjacent slides. Grooves 28 are preferably arranged in a diamond-shaped pattern.

[0030] FIG. 2:

[0031] A heating element 34 is embedded within hot plate 22 in FIG. 2. Heating element 34 is arranged in a zigzag pattern which is denser at the ends of hot plate 22 for providing even heating across the entire length of hot plate 22.

[0032] FIG. 3:

[0033] An additional slide supporting rack 13′ is positioned in a horizontal position in supporting notches 12 on bin 10 in FIG. 3. Several microscope slides 29 are placed in slide holding positions 20′. Finger notches 21 enable the ends of slides 29 to be easily gripped for removal. A pair of hydrophobic or liquid barriers 30 are drawn, preferably with a hydrophobic pen, across each slide 29 around specimens 31. A reagent is applied to slides 29 between the hydrophobic barriers. Barriers 30 limit the area that the reagent can cover on each slide so as to significantly reduce reagent usage. Because the reagent is applied to slides 29 individually, it is prevented from crossing between spaced apart slides 29, so that cross contamination during reagent application is eliminated. Hot plate 22′ is in the raised position engaged against the bottom of slides 29, and can be operated to heat slides 29 to a selected temperature. Since most of rack 13′ is made of a heat insulating material, it can be handled comfortably even while hot plate 22′ is in operation. Hot plate 22′ is preferably white in color for providing a light homogeneous background that facilitates viewing stained tissues on the slides. Hot plate 22′ is particularly useful for applications such as digestion, drying liquid mounting media, denaturing procedures for in situ hybridization, and isothermic temperature control.

[0034] FIG. 4:

[0035] As shown in FIG. 4, a pair of covers 32 and 32′ are removably positioned on shoulders 18 and 18′ of bases 16 and 16′ of slide supporting rack 13 and 13′ to define heating and humidity chambers that prevent the slides from drying out. Covers 32 and 32′ may be opaque for preventing radiant heat loss, and thus significantly speeding up the warm up time. Alternatively, covers 32 and 32′ may be transparent for viewing the slides. The hot plates (not shown) can be completely removed before applying covers 32 and 32′ so that the stainer is used only as humidity chambers.

[0036] FIG. 5:

[0037] After slides 29 are heated long enough, heating can be stopped immediately by moving hot plate 22′ in the direction indicated by the arrow in FIG. 5 to the lowered position to disengage it from slides 29. Grooves 28 enable hot plate 22′ to be easily separated from wet slides 29 by providing air channels under the slides and preventing suction. Hot plate 22′ can be moved back to the raised position to quickly begin heating again if desired.

[0038] FIG. 6:

[0039] In FIG. 6, slide supporting rack 13′ is placed in a tilted position for rinsing off the reagent by inserting tabs 14′ (one shown) in slanted supporting slots 33 (one shown) extending downwardly from notches 12 on bin 10. Because slides 29 are spaced laterally from each other, and also spaced above lowered hot plate 22′, the rinsing fluid will drain into the gaps between slides 29 without crossing over onto adjacent slides. Slides 29 are not touched by hand during heating or rinsing. Therefore, cross contamination between slides is eliminated. The rinsing fluid and reagent are collected in bin 10.

[0040] Accordingly, a microscope slide stainer is provided. It stains microscope slides. It reduces human handling of the slides by holding the slides during heating and rinsing. It heats the slides to selectable temperatures with a controllable hot plate. It starts and stops the heating very quickly by mechanically engaging and disengaging the hot plate from the slides. It enables the slides to be seen clearly against a white colored hot plate. It prevents radiated heat loss for faster warm up. It prevents the slides from drying out. It prevents the wet slides from sticking to the hot plate during disengagement. It tilts the slides to assist runoff during rinsing. It prevents the runoff from each slide from crossing over onto adjacent slides so as to eliminate cross contamination. It is particularly suitable for applications such as special stains, immunohistochemistry (including frozen sections, paraffin-embedded tissues, cell culture, and culture cells on coverslips), and in situ hybridization techniques (including DNA, mRNA, and Peptide Nucleic Acid).

[0041] Although the above description is specific, it should not be considered as a limitation on the scope of the invention, but only as an example of the preferred embodiment. Many variations are is possible within the teachings of the invention. For example, grooves 28 can be arranged in other patterns. Brackets 19 can be of other shapes. Direction-changing slots 26 and 27 can be of other shapes, such as two horizontal sections connected by a vertical section. Cover 32 can be transparent for enabling slide viewing during heating, but at the cost of reduced insulation. Grooves 27 can also extend through rails 15, and pins 25 can also be thumb-screw pins. Pins 24 and 25 can also be non-removable. More or fewer pairs of notches can be provided on bin 10 for supporting more or fewer racks 13. Therefore, the scope of the invention should be determined by the appended claims and their legal equivalents, not by the examples given.