This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2014-111886, filed May 30, 2014 the entire contents of which are incorporated herein by reference.
Embodiments described herein relate generally to a cuvette and an automatic analyzer.
An automatic analyzer for medical diagnosis automatically and quantitatively measures serum components concerning many items which are contained in a biological sample such as blood. This apparatus is widely used for clinical examination. The automatic analyzer discharges a serum sample and a reagent into a cuvette, stirs the serum sample and the reagent in the cuvette, and optically performs colorimetric measurement of the liquid mixture of the serum sample and the reagent. At this time, it is necessary to uniformly stir the serum sample and the reagent in the shortest time as possible. The establishment of an effective stirring means for this purpose influences the performance of the apparatus.
Each cuvette used in the automatic analyzer is a small rectangular cuvette having a volume of several hundred μL. A material for a cuvette for optical measurement, a glass material such as synthetic quartz is generally used. Various studies have been made on methods of efficiently stirring a sample and a reagent in this minute cuvette. A glass cuvette having a hydrophilic surface suffers from the solution creeping phenomenon that a liquid in a corner portion of the cuvette rises toward the opening of the cuvette by a capillary action. This causes faulty stirring of the sample and the reagent contained in the cuvette.
In general, according to an embodiment, cuvette has a bottom wall and a side wall. The bottom wall has a bottom surface. The side wall is connected to the bottom wall so as to surround the bottom surface. The inner surface of the side wall is alternately provided, in the long axis direction of the side wall, with first contact angle regions, each having a first contact angle with respect to a liquid, and second contact angle regions, each having a second contact angle larger than the first contact angle.
A cuvette and an automatic analyzer according to this embodiment will be described below with reference to the accompanying drawing.
The analysis mechanism 2 operates under the control of the analysis mechanism controller 3. The analysis mechanism 2 is provided in the housing of the automatic analyzer. For example, as shown in
The reaction disk (holding mechanism) 11 holds a plurality of cuvettes 31 arrayed on a circumference. The reaction disk 11 alternately and repeatedly pivots and stops at predetermined time intervals. The sample disk 13 is arranged near the reaction disk 11. The sample disk 13 holds sample tubes 33 accommodating samples. The sample disk 13 pivots to locate the sample tube 33 accommodating a dispensing target sample at a sample suction position. The first reagent reservoir 15 holds a plurality of first reagent containers 35 accommodating first reagents which selectively react concerning the measurement items of a sample. The first reagent reservoir 15 pivots to locate the first reagent container 35 accommodating the first reagent as a dispensing target at the first reagent suction position. The second reagent reservoir 17 is arranged near the reaction disk 11. The second reagent reservoir 17 holds a plurality of second reagent containers 37 accommodating second reagents corresponding to the first reagents. The second reagent reservoir 17 pivots to locate the second reagent container 37 accommodating the second reagent as a dispensing target at the second reagent suction position.
The sample arm 19-1 is arranged between the reaction disk 11 and the sample disk 13. The sample probe 21-1 is attached to the distal end of the sample arm 19-1. The sample arm 19-1 supports the sample probe 21-1 so as to allow it to vertically move. The sample arm 19-1 also supports the sample probe 21-1 so as to allow it to pivot along an arcuate pivoting path. The pivoting path of the sample probe 21-1 passes through the sample suction position on the sample disk 13 and the sample discharge position on the reaction disk 11. The sample probe 21-1 sucks a sample from the sample tube 33 arranged at the sample suction position on the sample disk 13, and discharges the sample to the cuvette 31 arranged at the sample discharge position on the reaction disk 11.
The first reagent arm 19-2 is arranged near the outer circumference of the reaction disk 11. The first reagent probe 21-2 is attached to the distal end of the first reagent arm 19-2. The first reagent arm 19-2 supports the first reagent probe 21-2 so as to allow it to vertically move. The first reagent arm 19-2 also supports the first reagent probe 21-2 so as to allow it to pivot along an arcuate pivoting path. The pivoting path of the first reagent probe 21-2 passes through the first reagent suction position on the first reagent reservoir 15 and the first reagent discharge position on the reaction disk 11. The first reagent probe. 21-2 sucks the first reagent from the first reagent container 35 arranged at the first reagent suction position on the first reagent reservoir 15, and discharges the first reagent to the cuvette 31 arranged at the first reagent discharge position on the reaction disk 11.
The second reagent arm 19-3 is arranged between the reaction disk 11 and the second reagent reservoir 17. The second reagent probe 21-3 is attached to the distal end of the second reagent arm 19-3. The second reagent arm 19-3 supports the second reagent probe 21-3 so as to allow it to vertically move. The second reagent arm 19-3 also supports the second reagent probe 21-3 so as to allow it to pivot along an arcuate pivoting path. The pivoting path of the second reagent probe 21-3 passes through the second reagent suction position on the second reagent reservoir 17 and the second reagent discharge position on the reaction disk 11. The second reagent probe 21-3 sucks the second reagent from the second reagent container 37 arranged at the second reagent suction position on the second reagent reservoir 17, and discharges the second reagent to the cuvette 31 arranged at the second reagent discharge position on the reaction disk 11.
A stirring unit 23 is arranged near the outer circumference of the reaction disk 11. A stirring bar holding mechanism (support unit) 23-1 and a stirring bar 23-2 are attached to the stirring unit 23. The stirring bar holding mechanism 23-1 supports the stirring bar 23-2 so as to allow it to vertically move. The stirring bar holding mechanism 23-1 lowers the stirring bar 23-2 into the cuvette 31 arranged at a stirring position on the reaction disk 11. After the stirring bar 23-2 is lowered, the stirring unit 23 vibrates the stirring bar 23-2 to stir the liquid mixture of the sample and the first reagent or the liquid mixture of the sample and the first and second reagents in the cuvette 31. These liquid mixtures will be referred to as reaction liquids.
The optical measurement unit 25 is provided near the reaction disk 11. The optical measurement unit 25 operates under the control of the analysis mechanism controller 3. More specifically, the optical measurement unit 25 includes a light source 210 and a detector 220. The light source 210 generates light. The detector 220 detects the light emitted by the light source and transmitted through the cuvette 31 and the reaction liquid, the light reflected by the cuvette 31 and the reaction liquid, or the light scattered by the cuvette 31 and the reaction liquid. The detector 220 generates data (to be referred to as photometric data hereinafter) representing a measurement value corresponding to the intensity of detected light. The generated photometric data is supplied to the analysis unit 4.
The cleaning unit 27 is provided on the outer circumference of the reaction disk 11. The cleaning unit 27 operates under the control of the analysis mechanism controller 3. More specifically, the cleaning unit 27 includes a cleaning nozzle and a drying nozzle. The cleaning unit 27 cleans the cuvette 31 at a cleaning position of the reaction disk 11 with the cleaning nozzle, and dries the cuvette 31 with the drying nozzle.
The analysis mechanism controller 3 operates the respective apparatuses and mechanisms of the analysis mechanism 2 under the control of the system controller 8. The analysis unit 4 calculates a measurement item value concerning colorimetric measurement of a reaction liquid based on photometric data. More specifically, the analysis unit 4 calculates the absorbance of the reaction liquid based on the photometric data, and calculates a measurement item value based on the calculated absorbance. The monitor 5 includes, for example, a display device such as a CRT display, liquid crystal display, organic EL display, or plasma display. The monitor 5 displays the analysis result such as the measurement item value or the like calculated by the analysis unit 4. The operation unit 6 accepts various types of commands and information inputs from the operator via an input device. As the input device, it is possible to use pointing devices such as a mouse and a trackball, selection devices such as switches and buttons, and input devices such as a keyboard, as needed. The memory 7 stores operation programs and the like for the automatic analyzer 1. The system controller 8 functions as the main unit of the automatic analyzer 1. The system controller 8 reads out operation programs from the memory 7, and controls the units 3, 4, 5, and 7 in accordance with the operation programs.
The stirring unit 23 of the automatic analyzer 1 according to this embodiment will be described next.
As shown in
The stirring unit 23 is connected to a power supply (not shown) via a cable. The power supply converts an external voltage into an AC voltage and applies the AC voltage to the obverse side vibrator 51-1 and the reverse side vibrator 51-2. Upon receiving the applied AC voltage, the obverse side vibrator 51-1 and the reverse side vibrator 51-2 alternately extend and contract to vibrate the blade 55.
The cuvette 31 according to this embodiment will be described in detail next.
Although described in detail later, hydrophilic regions and hydrophobic regions are provided on the inner surface of the cuvette 31 according to this embodiment in accordance with a predetermined array pattern. The hydrophilic regions are inner surface regions, of the inner surfaces of the cuvette 31, which exhibit hydrophilicity. The hydrophobic regions are inner surface regions, of the inner surfaces of the cuvette 31, which exhibit hydrophobicity. Assume that in this embodiment, hydrophilicity and hydrophobicity are defined with reference to contact angles. A contact angle is defined by the angle formed by the liquid level of a liquid adhering to an object and the solid surface of the object.
Measurement of the contact angle of a liquid will be described below. A contact angle can be measured by, for example, a static contact angle measuring apparatus. The static contact angle measuring apparatus optically shoots a liquid at rest on a solid with an optical camera, and measures a contact angle by processing an output image from the optical camera. As a contact angle measurement principle, any existing method may be used. For example, the θ/2 method is preferably used. Measurement of a contact angle by the θ/2 method will be described below.
γS=γL cos θ+γSL (1)
θ=2·θ1 (2)
Therefore, equation (3) given below holds. In this equation, r is defined by the radius of a contact surface S1 of the liquid region R1, and h is defined by the height of the liquid region R1. More specifically, the radius r is defined by ½ the length of the contact surface S1 of the liquid region R1 with respect to the solid region R2. The height h is defined by the distance between the vertex P2 and the contact surface S1 of the liquid region R1. The static contact angle measuring apparatus calculates the contact angle θ based on the radius r and the height h according to equation (3). More specifically, the static contact angle measuring apparatus specifies the liquid region R1 and the solid region R2 included in an output image by image processing, measures the radius r and the height h based on the liquid region R1 and the solid region R2, and calculates the contact angle θ by substituting the radius r and the height h into equation (3).
As a liquid to be used for the measurement of a contact angle, a standard liquid is used, which represents the properties of various types of liquids to be analyzed by the automatic analyzer 1. For example, as this liquid, it is preferable to use water, ion-exchanged water, or glycerin solution. In this embodiment, when a standard liquid is dropped, a solid from which the contact angle θ smaller than a predetermined reference angle is measured is defined as being hydrophilic. When the same type of liquid is dropped, a solid from which the contact angle θ larger than the predetermined reference angle is measured is defined as being hydrophobic. A reference angle can be arbitrarily set in accordance with the properties of a standard liquid. However, in the following description, assume that the reference angle is 90°. That is, in the following embodiment, as shown in
A method of forming hydrophilic regions and hydrophobic regions will be described below. First of all, the prospective formation regions of hydrophilic regions and the prospective formation regions of hydrophobic regions are positioned. The prospective formation regions of hydrophilic regions and the prospective formation regions of hydrophobic regions are set such that hydrophilic regions and hydrophobic regions are alternatively provided in the height direction. The width and intervals of the prospective formation regions of hydrophilic regions and those of the prospective formation regions of hydrophobic regions can be arbitrarily set.
If, for example, the cuvette 31 is formed from a material exhibiting hydrophilicity (to be referred to as a hydrophilic material hereinafter), only the prospective formation regions of hydrophobic regions of the inner surfaces of the cuvette 31 are coated with a material exhibiting hydrophobicity (to be referred to as a hydrophobic material hereinafter). The prospective formation regions of hydrophilic regions are not coated with a hydrophobic material.
A hydrophilic material used as a material for the cuvette 31 is, for example, silicone dioxide (SiO2). A hydrophobic material for coating is, for example, a fluorine compound, octadecyltrichlorosilane (OTS), silicone resin, paraffin, or a compound having a hydrophobic group. As a fluorine compound, for example, a compound having a fluoroalkyl chain is used to bond a fluoromethyl group (CF3) to the terminal of a solid structure. Typically, as a fluorine compound, it is preferable to use Teflon® as a kind of fluorine resin. Octadecyltrichlorosilane is used to form a highly adhesive hydrophobic film on a silicone oxide film. As compound having a hydrophobic group, a compound having a hydrocarbon group (for example, a methyl group, vinyl group, or alkyl group) or a benzene ring is used.
Note that the material for the cuvette 31 need not always have hydrophilicity. In this case, the inner surface of the cuvette 31 may be coated with a hydrophilic material to form hydrophilic regions on the inner surface of the cuvette 31. In this case, as a hydrophilic material for coating, for example, titanium oxide (TiO2), a glass material containing a hydroxyl group or a compound having a hydrophilic group is used. Note that titanium oxide has a property called superhydrophilicity upon receiving ultraviolet light. Superhydrophilicity is the property that a liquid contacts a solid at a contract angle as close to 0° as possible. When each hydrophilic region preferably has superhydrophilicity, the titanium oxide with which the inner surface of the cuvette is coated is preferably irradiated with ultraviolet light.
Note that it is possible to change the degree of hydrophilicity, i.e., the contact angle formed by a liquid, in accordance with the roughness of the surface of each hydrophilic region. For example, as the smoothness of the surface of each hydrophilic region is increased, the hydrophilicity of the hydrophilic region can be increased, that is, the contact angle can be decreased. Likewise, it is possible to change the degree of hydrophobicity, i.e., the contact angle formed by a liquid, in accordance with the roughness of the surface of each hydrophobic region. For example, as the roughness of the surface of each hydrophobic region is increased, the hydrophobicity of the hydrophobic region can be increased, that is, the contact angle can increased. The surface of each hydrophobic region is preferably roughened by sand blasting or the like.
In addition, the method of forming hydrophilic regions and hydrophobic regions is not limited to coating. For example, hydrophilic regions and hydrophobic regions may be formed by surface micropatterning. The micropatterns of hydrophilic regions and hydrophobic regions formed by the surface micropatterning include a line-and-space pattern and a pillar pattern. The micropatterns of hydrophilic regions and hydrophobic regions are formed by, for example, chemical or mechanical surface treatment technique.
According to the above description, the hydrophilic regions 71 and the hydrophobic regions 73 are provided along the horizontal direction. However, this embodiment is not limited to this. For example, the hydrophilic regions 71 and the hydrophobic regions 73 may be provided along a direction tilting from the horizontal direction at a predetermined angle. In addition, the shape of each pillar structure 75 is not limited to a circular columnar shape and may be a rectangular columnar shape.
The effect obtained by alternately arraying the hydrophilic regions 71 and the hydrophobic regions 73 according to this embodiment will be described next. As shown in
In addition, if a hydrophobic region is provided on the bottom surface, since a liquid is sucked to the side wall inner surfaces, the bottom surface may be exposed when the amount of liquid is small. The bottom surface 61S of the bottom wall 61 according to this embodiment is provided with the hydrophilic region 71. If the bottom surface 61S is provided with the hydrophilic region 71, since a liquid is uniformly distributed on the bottom surface 61S, the bottom surface 61S is not easily exposed even if the amount of liquid is small. According to the embodiment, therefore, it is possible to uniformly mix a liquid in the cuvette 31 as compared with a case in which the bottom surface 61S has hydrophobicity, even if the amount of liquid is small.
As described above, the cuvette 31 according to this embodiment has the bottom wall 61 having the bottom surface 61S and side walls 63 connected to the bottom wall 61 so as to surround the bottom surface 61S. The side wall inner surfaces 63S of the side wall 63 are alternately provided, in the height direction, with hydrophilic regions 71, each having the first contact angle with respect to a liquid contained in the cuvette 31, and the hydrophobic regions 73, each having the second contact angle larger than the first contact angle. Since the amounts of liquid contained in the cuvettes 31 differ from each other, the liquid levels of liquids sometimes vary. However, alternately arraying the hydrophilic regions 71 and the hydrophobic regions 73 on the side wall inner surfaces 63S makes it possible to prevent the generation of air bubbles or minute liquid droplets by stirring and the adhesion of the air bubbles or minute liquid droplets to the side wall inner surfaces 63s while suppressing the creeping of the liquid along the side wall inner surfaces 63S regardless of the amount of liquid. Consequently, according to this embodiment, it is possible to more uniformly mix a liquid in the cuvette 31 than in the related art, in which only hydrophilic regions or hydrophobic regions are provided on the entire side wall inner surfaces.
Various application examples according to this embodiment will be described next.
The large inner surfaces 65S are perpendicular to the vibrating direction, and hence a wavy liquid tends to collide with the large inner surfaces 65S because of the vibration of the blade 55, as compared with the small inner surfaces 67S. For this reason, a liquid tends to creep up on the large inner surfaces 65S as compared with the small inner surfaces 67S. It is possible to suppress the creeping of a liquid along the large inner surfaces 65S along with stirring by alternately providing the hydrophilic regions 71 and the hydrophobic regions 73 in the height direction on the large inner surfaces 65S. In addition, since each hydrophilic region 71 is vertically sandwiched between the hydrophobic regions 73 on the large inner surfaces 65S, liquid droplets adhering to the hydrophilic regions 71 flow in the horizontal direction to the small inner surfaces 67S. As described above, the hydrophilic regions 71 are provided on the entire surfaces of the small inner surfaces 67S. For this reason, the small inner surfaces 67S having the hydrophilic regions 71 can make liquid droplets flowing from the large inner surfaces 65S flow downward. In addition, since the hydrophilic regions 71 are provided on the entire surfaces of the small inner surfaces 67S, a liquid which has directly collided with the small inner surfaces 67S because of the vibration or the like of the blade 55 flows downward. As the liquid flows downward, a recess in the central portion of the liquid, which is formed along with stirring, is eliminated. This makes it possible to improve faulty stirring caused by the recess in the central portion.
As described above, the cuvette 31 according to application example 1 can improve faulty stirring caused by the recess in the central portion of a liquid, which is formed by stirring; while suppressing the creeping of the liquid along the side wall inner surfaces 65s. As compared with the related art, therefore, a liquid can be quickly and uniformly mixed. Note that the creeping of a liquid more easily occurs on the side wall inner surfaces perpendicular to the vibrating direction than on the side wall inner surfaces parallel to the vibration direction. Therefore, in order to maximize the effects of suppressing the creeping of a liquid and eliminating the recess in the central portion of the liquid, it is preferable to arrange the cuvette 31 according to application example 1 in the reaction disk 11 so as to make the large-area side walls 65, on which the hydrophilic regions and the hydrophobic regions are alternately provided, become perpendicular to the vibrating direction.
Note that in the above description, the side walls alternately provided with the hydrophilic regions 71 and the hydrophobic regions 73 are two side walls facing each other. However, this embodiment is not limited to this. For example, the hydrophilic regions 71 and the hydrophobic regions 73 may be alternately provided on two adjacent side walls. In addition, the side walls alternately provided with the hydrophilic regions 71 and the hydrophobic regions 73 are not limited to two side walls of the fourth side walls. That is, such regions may be provided on three side walls or one side wall. The side wall inner surfaces which are not alternately provided with the hydrophilic regions 71 and the hydrophobic regions 73 may be provided with the hydrophilic regions 71 to make liquid droplets adhering to the side wall inner surfaces flow downward.
As described above, since the amount of liquid to be stirred is not constant, the liquid levels of liquids in a plurality of cuvettes 31 vary. The smaller the amount of liquid, the lower the height the liquid creeps up. If the width of the hydrophilic region 71 and the hydrophobic region 73 is too large as compared with the height by which a liquid creeps up, the effect of suppressing the creeping of a liquid cannot be obtained. In contrast to this, if the width of the hydrophilic region 71 and the hydrophobic region 73 is too small as compared with the height by which a liquid creeps up, the creeping of a liquid is excessively suppressed. This makes it easy to generate air bubbles or minute liquid droplets. As a method of simultaneously solving the two problems, there is conceivable a method of switching between the vibration modes of the blade in accordance with the amount of liquid. However, a mechanism having a plurality of vibration modes is complicated and expensive.
In the cuvette 31 according to application example 2, the widths of the hydrophilic regions 71 and the hydrophobic regions 73 gradually decrease toward the bottom surface 61S of the cuvette 31, and gradually increase toward the opening. Therefore, it is possible to properly suppress the creeping of a liquid by a capillary action in accordance with the amount of liquid while preventing the generation of air bubbles or minute liquid droplets without switching between the vibration modes of the blade 55.
The cuvette 31 according to application example 3 will be described below. Note that the same reference numerals as in this embodiment denote constituent elements having almost the same functions in the following description, and a repetitive description will be made only when required.
Note that an array pattern of the hydrophilic regions 71 and the hydrophobic regions 73, which is indicated by the side wall inner surface 63S-3 described above, may be provided on the inner surface of any side wall 61 of the four side walls 61 included in the cuvette 31.
The cuvette 31 according to application example 4 will be described below. Note that the same reference numerals as in this embodiment denote constituent elements having almost the same functions in the following description, and a repetitive description will be made only when required.
An array pattern of the hydrophilic regions 71 and the hydrophobic regions 73 according to application example 4 can enhance hydrophilicity in the horizontal direction as compared with a case in which the hydrophobic region 73 is entirely provided on the side wall inner surface. That is, the first inner surface regions 85 alternately provided with the hydrophilic regions 71 and the hydrophobic regions 73 in the horizontal direction and the second inner surface regions 87 provided with the hydrophobic regions 73 are alternately provided in the height direction, thereby suppressing the adhesion of a liquid to the side wall inner surface 63S-4 while suppressing the creeping of a liquid by a capillary action.
The cuvette 31 according to application example 5 will be described below. Note that the same reference numerals as in this embodiment denote constituent elements having almost the same functions in the following description, and a repetitive description will be made only when required.
According to application example 5, it is possible to prevent a deterioration in the accuracy of optical measurement.
According to the above embodiment, the side wall 63 of the cuvette 31 has a rectangular cylindrical shape. However, this embodiment is not limited to this. The cuvette 31 according to the embodiment can be applied to any existing shape. The cuvette 31 according to a modification of the embodiment will be described below. Note that the same reference numerals as in this embodiment denote constituent elements having almost the same functions in the following description, and a repetitive description will be made only when required.
According to modification 1, therefore, even the cuvette 91 having a circular cylindrical shape can prevent the generation of air bubbles or minute liquid droplets by stirring and the adhesion of the air bubbles or minute liquid droplets to the side wall inner surface 73S while suppressing the creeping of the liquid along the side wall inner surface 95S, regardless of the amount of liquid, by alternately providing the hydrophilic regions 71 and the hydrophobic regions 73 in the height direction on the side wall inner surface 95S. This makes it possible to more uniformly mix a liquid in the cuvette 91.
According to the above embodiment, the stirring unit 23 is configured to stir a liquid in the cuvette 31 or 91 by reciprocating the blade 55. However, this embodiment is not limited to this. The stirring mode of the stirring unit 23 according to the embodiment can be applied to any existing modes. For example, the stirring unit 23 may stir a liquid by rotating the blade 55 having a paddle mounted on its distal end portion about the main shaft of the blade 55. The cuvettes 31 and 91 according to these modifications can have the same effects as those of the embodiment described above, regardless of the stirring mode, by alternately providing the hydrophilic regions 71 and the hydrophobic regions 73 in the height direction on the inner surfaces 31S and 91S.
While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. Indeed, the novel methods and systems described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions and changes in the form of the methods and systems described herein may be made without departing from the spirit of the inventions. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the inventions.
Number | Date | Country | Kind |
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2014-111886 | May 2014 | JP | national |