This application claims the priority of Chinese Patent Application No. 202311422545.7, filed on October 30, 2023, the disclosure of which is incorporated herein in its entirety by reference.

The at least one embodiment of the disclosed invention is related to a centrifugal liquid separation device and operating method, especially meaning a centrifugal liquid separation device with multi-stage separation design and the operating method per se.

There are various biological tests. For example, plasma is an important biological specimen which provides a lot of physiological or clinical information, enabling the medics or test institution to quickly understand physical condition(s) of individual.

However, taking the aforementioned purpose as an example, for accomplishing the separation of biological samples, most of the blood tests require the separation of whole blood to obtain the desired item (such as the item required by blood coagulation tests). Therefore, research and development of separation technologies has been ongoing. For instance, a method that performs high efficiency and speed in separating platelets or plasma from whole blood is the main development purpose.

Traditionally, the separation of biological samples is accomplished by the centrifugal force generated by the high-speed rotation of a centrifuge to separate test targets with different specific gravities within a test tube. However, the pretreatment procedures for the samples and the cleaning of the equipment after separation are quite time-consuming, and even though most of the tests only require a few amount of sample. Hence, traditional separation methods still consume a large amount of blood for obtaining the samples.

In light of the development of the recent biomedical testing technology, the related separation techniques have also advanced significantly. For example, the well-known centrifugal microfluidics (i.e. laboratory discs) utilizes micro-channel structures combined with electrophoresis or dielectrophoresis to separate liquids such as blood. However, the corresponding testing conditions are not entirely conductive to obtaining intact samples. Taking blood samples for instance, the blood must be diluted at first before being placed in a high-voltage environment for separation. These basic steps may lead to deterioration or contamination of the final sample.

Therefore, the object of the present invention is to provide a sample method for efficiently separating liquids (such as blood) in an environment that does not require high voltage.

To solve the problem mentioned in the previous background of art, some of the embodiments of the disclosed invention provide a centrifugal liquid separation device and operating method, especially meaning a centrifugal liquid separation device with multi-stage separation design and the operating method with the advantages of simple operation process and high efficiency for cleaning. The centrifugal multi-stage liquid separation device separates each component with different densities in the liquid and performs the combination of oscillation and release via controlling the rotation speed parameter. Hence, the step of surface hydrophilic treatment of the traditional flow channel wall may be omitted. On the other hand, the operation method may even complete the liquid separation by simply operating two types of rotation speed stages such as high speed and low speed under some conditions or situations.

The at least one embodiment of the disclosed invention is a centrifugal multi-stage liquid separation device which includes a body and a micro-channel structure. The micro-channel structure is embedded in the body. The micro-channel structure includes a sample adding section, a first density section, a temporary storage section and a second density section. The first density section connects to the sample adding section. The temporary storage section connects to the first density section. The sample adding section, the first density section, the temporary storage section and the second density section are mainly and respectively arranged from inside to outside according to a center of rotation in the micro-channel structure.

At least one embodiment of the disclosed invention is an operating method of centrifugal multi-stage liquid separation device which comprises the steps as follows. Providing the centrifugal multi-stage liquid separation device, and adding the liquid into the sample adding section. The body is driven to rotate at a high rotation speed, causing the liquid to enter the first density section and the second density section. The liquid with higher density is retained in the second density section based on the effect of centrifugal force. Thereafter, the rotation direction of the body is switched to create oscillation, allowing the liquid with lower density to overcome the restriction of the surface tension to flow into a first storage section through the first flow channel. Finally, the body keeps being oscillated until the liquid retained in the first density section is exhausted and enters the first storage section, thereby obtaining a first separated liquid and a second separated liquid respectively.

At least one embodiment of the disclosed invention is an operating method of centrifugal multi-stage liquid separation device which comprises the steps as follows. Providing the centrifugal multi-stage liquid separation device and a second flow channel, and the second flow channel connects to the first density section. Adding a liquid into the sample adding section of micro-channel structure. The body is driven to rotate at a high rotation speed, causing the liquid to enter the first density section and the second density section. The liquid with higher density is retained in the second density section based on the effect of centrifugal force. Thereinafter, the rotation direction of the body is reversely changed, allowing the liquid with lower density to overcome the restriction of the surface tension and to flow into a second storage section through the second flow channel. Finally, the rotating direction of the body is switched again, thus the remaining liquid with lower density breaks the restriction of the surface tension and flows into a first storage section through the first flow channel. The rotation speed is maintained until all the remaining liquid in the first density section is exhausted, to obtain a first separated liquid, a second separated liquid and a third separated liquid respectively.

At least one embodiment of the disclosed invention is an operating method of centrifugal multi-stage liquid separation device which comprises the steps as follows. Providing the centrifugal multi-stage liquid separation device and a second flow channel, and the second flow channel connects to the first density section. Adding a liquid into the sample adding section of micro-channel structure. The body is driven to rotate at a high rotation speed, causing the liquid to enter the first density section and the second density section. The liquid with higher density is retained in the second density section based on the effect of centrifugal force. Thereafter, reducing the rotation speed until the body stops rotating, and the first separated liquid soaks the second flow channel via capillary action. Restarting and speeding the rotation speed up to a speed threshold then causes the first separated liquid with lower density to climbing up and entering a second storage section through the second flow channel to form a second separated liquid. Furthermore, switching the rotation direction of the body to create oscillation, and the liquid with lower density may gradually oscillate, soak and pass through the first flow channel. Finally, speeding the rotation speed of the body again, and the remaining liquid with lower density breaks the limitation of the surface tension and flows into a first storage section through the first flow channel. Simultaneously, the rotation is maintained until all the remaining liquid in the first density section is exhausted, thereby obtaining a first separated liquid, a second separated liquid and a third separated liquid respectively.

At least one embodiment of the present invention is characterized in the control of the solution. In some situations, the first flow channel and second flow channel are liquid flow channel which have not be processed by hydrophilic modification treatment yet.

At least one embodiment of the disclosed invention is an operating method of centrifugal multi-stage liquid separation device which comprises the steps as follows. Providing the centrifugal multi-stage liquid separation device, a second flow channel and a separation structure. The second flow channel connects to the first density section, and the second flow channel connects to the separation structure. The separation structure includes a separation section, at least one quantitative chamber and at least one reaction chamber. The separation section connects to the quantitative chamber. The quantitative chamber connects to the reaction chamber. Adding a liquid into the sample adding section of micro-channel structure. The body is driven to rotate at a high rotation speed, causing the liquid to enter the first density section and the second density section. Furthermore, the rotation direction of the body is switched and the rotation speed is reduced to a low speed threshold, and the first separated liquid with lower density may climb up and enter the separation section and the at least one quantitative chamber through the second flow channel. After the quantitative chamber is filled, the rotation speed is sped up to a high speed threshold, allowing the second separated liquid of the at least one quantitative chamber entering the at least one reaction chamber to perform a reaction. Finally, the rotation direction of the body is switched again, and the remaining liquid breaks the limitation of the surface tension and flows into a first storage section through the first flow channel. The rotation is maintained until all the remaining liquid in the first density section is exhausted, thereby obtaining a first separated liquid, a second separated liquid and a third separated liquid respectively.

To clearly describe the embodiment of the present application or the technique of the prior art, the following description may illustrate the essential drawings briefly. Obviously, the drawings mentioned as follows are just the embodiments of the present application.

• Fig. 1 illustrates a schematic diagram of the centrifugal multi-stage liquid separation device according to some embodiments of the disclosed invention.
• Fig. 2 illustrates another schematic diagram of the centrifugal multi-stage liquid separation device according to some embodiments of the disclosed invention.
• Fig. 3 illustrates the other schematic diagram of the centrifugal multi-stage liquid separation device according to some embodiments of the disclosed invention, used to explain the connection relationship of the components in Fig. 1 and Fig. 2.
• Fig. 4 illustrates a flow chart of the centrifugal multi-stage liquid separation device operating method according to some embodiments of the disclosed invention.
• Fig. 5 illustrates another flow chart of the centrifugal multi-stage liquid separation device operating method according to some embodiments of the disclosed invention.
• Fig. 6 illustrates the other flow chart of the centrifugal multi-stage liquid separation device operating method according to some embodiments of the disclosed invention.
• Fig. 7 to Fig. 14 illustrate schematic diagrams of the centrifugal multi-stage liquid separation device operating method corresponding to the centrifugal multi-stage liquid separation device according to some embodiments of the disclosed invention.
• Fig. 13 illustrates schematic diagram of the centrifugal multi-stage liquid separation device according to some embodiments of the disclosed invention.
• Fig. 16 illustrates a flow chart of the centrifugal multi-stage liquid separation device operating method according to some embodiments of the disclosed invention.
• Fig. 17 to Fig. 24 illustrate schematic diagrams of the centrifugal multi-stage liquid separation device operating method corresponding to the centrifugal multi-stage liquid separation device according to some embodiments of the disclosed invention.

In the drawings: body 10, micro-channel structure 20, sample adding section 21, first density section 22, second density section 23, temporary storage section 24, sample inlet port 211, vent 212, first flow channel 221, second flow channel 223, reflux structure 225, first bending part 221a, first storage section 221b, second bending part 223a, second storage section 223b, liquid 60 or 70, portion with high density 61 or 71, portion with medium density 62 or 72, portion with low density 63 or 73, first port f1, second port f2, third port f3, fourth port f4, separation structure 30, separation section 31, quantitative chamber 311, reaction chamber 313 and waste solution chamber 315.

The at least one embodiment of the disclosed invention is a centrifugal liquid separation device and the operating method per se, especially meaning a centrifugal liquid separation device with multi-stage separation design and the operating method per se.

Please refer to Fig.1, Fig. 1 illustrates a schematic diagram of the centrifugal multi-stage liquid separation device according to some embodiments of the disclosed invention. The centrifugal multi-stage liquid separation device includes a body 10 and a micro-channel structure 20. The body 10 is used as a medium to drive and control the movement of micro-channel structure 20. In this embodiment, the micro-channel structure 20 is embedded in the body 10. The micro-channel structure 20 includes a sample adding section 21, a first density section 22, a second density section 23 and a temporary storage section 24 which are used to perform various tests. Otherwise, as shown in Fig. 1, the sample adding section 21, the first density section 22, the temporary storage section 24 and the second density section 23 are arranged from inside to outside according to a center of rotation in the micro-channel structure 20 respectively. The shape of body 10 shown in Fig. 1 may be a symmetrical disc such as a circle, a square or polygon. The material of the body 10 may be Polymethylmethacrylate (PMMA), Polyethylene Terephthalate (PET), Polycarbonate (PC), Polydimethylsilicon (PDMS), silicone, rubber, plastic, glass or the combinations thereof. The body 10 is detachable and may be placed in a centrifuge or rotary motor for centrifugation. When the body 10 is subjected to force, the body 10 will drive the micro-channel structure 20 to operate together. The sample adding section 21 illustrated in the Fig.1 includes a sample inlet port 211 and a vent 212. The shape of the sample inlet port 211 and the vent 212 may be circular or polygonal. One side of the first density section 22 is connected to the sample adding section 21, and the other side of the first density section 22 is connected to the second density section 23. The first density section 22 includes a first flow channel 221. The first flow channel 221 is bent away from the sample adding section 21 to form a first bending part 221a. The first bending part 221a is to buff the flow velocity of the liquid sample in the first flow channel 221.

The sample adding section 21 illustrated in the Fig. 1 may contain a liquid such sample, buffer Solution, wash Buffer, reagent or solvent. In some embodiments of the disclosed invention, the liquid of the embodiment is a blood solution which is taken as an example for illustration, but the disclosed invention is not limited.

Fig. 2 illustrates another schematic diagram of the centrifugal multi-stage liquid separation device according to some embodiments of the disclosed invention. The difference between Fig.1 and Fig. 2 is that the centrifugal multi-stage liquid separation device may further include a second flow channel 223. The second flow channel 223 connects to first density section 22 and temporary storage section 24. The second flow channel 223 is bent away from the sample adding section 21 to form a second bending part 223a. The second bending part 223a is used to buff the flow velocity of the liquid which flows in the second flow channel 223. In this embodiment, the second flow channel 223 may be configured at a height higher than the first flow channel 221 to create a height difference (i.e. the second flow channel 223 is closer to the sample adding section 21 than the first flow channel 221).

The first bending part 221a and second bending part 223a respectively illustrated in Fig. 1 and Fig. 2 may be used to prevent liquid from passing through the first flow channel 221 and the second flow channel 223 prematurely due to centrifugal force before the intended condition. For example, when the body 10 of the centrifugal multi-stage liquid separation device is operating, the liquid is designed to be retained in the first flow channel 221 and the second flow channel 223 based on capillary properties. When the rotation speed of the body 10 speeds up and causes the centrifugal force being greater than the surface tension of the liquid, the liquid will begin to climb up and pass through the first bending part 221a and the second bending part 223a due to the force generated by the angular velocity of the rotation speed.

In light of the micro-channel structure 20 illustrated in the aforementioned embodiment (as shown in Fig.1 and Fig. 2), the width of each of the first flow channel 221 and the second flow channel 223 is between 0.1 mm and 1.0 mm. The directions of the first flow channel 221 and the second flow channel 223 with respect to the normal direction of rotation center and the direction to boundary between the first flow channel 221 and the second flow channel 223 and the first density section 22 respectively to form angles between 30 degrees and 80 degrees.

Fig. 3 illustrates a the other schematic diagram of the centrifugal multi-stage liquid separation device according to some embodiments of the disclosed invention, used to explain the configuration of the components recited in Fig. 1 and Fig. 2. The first density section 22 of Fig. 3 includes at least one reflux structure 225. The reflux structure 225 may be heart-shaped or other structures with two symmetrical arc-shaped edges, but it is not limited. In the embodiment of the Fig. 3, the main function of the reflux structure 225 is to regulate the liquid flow direction. For example, when the liquid flows to the periphery of the first density section 22 due to centrifugal force simulating gravity, the shape design of the reflux structure 225 will guide the liquid to turn downward to form a single direction guide, thus to regulate the liquid flow direction. As shown in Fig. 3, the first density section 22 is also connected with temporary storage section 24 which communicates with the external atmospheric environment, therefore to reduce the resistance caused by air pressure while the liquid flowing in the first density section 22. In Fig. 1, Fig. 2 and Fig. 3, the temporary storage section 24 is configured to be connected with the first density section 22 and the first flow channel 221, for guiding the liquid in the first density section 22 to flow to the first flow channel 221.

Please refer to Fig. 1 and Fig. 2, the liquid will flow into the storage section (as shown in Fig. 3) through the first flow channel 221 and/or the second flow channel 223 after centrifugation. For a brief explanation, the storage section connects with the first flow channel 221 is defined as a first storage section 221b, and the storage section connects with the second flow channel 223 is defined as a second storage section 223b. Furthermore, the storage section may be further divided into multiple storage units (not shown in the figure) as needs, thus each storage unit isolated from the others may further accomplish the separation of the liquid.

As shown in Fig. 3, the connection point between the first flow channel 221 and the first density section 22 via the temporary storage section 24 is called the first port f1, and the connection point between the first flow channel 221 and the first storage section 221b is called the second port f2. The first bending part 221a is configured between the first port f1 and the second port f2. In relative, the connection between the second flow channel 223 and the first density section 22 is called the third port f3, and the connection between the second flow channel 223 and the second storage section 223b is called the fourth port f4. The second bending part 223a is configured between the third port f3 and the fourth port f4.

The height differences between the first port f1 and the second port f2, the first port f1 and third port f3 and the third port f3 and fourth port f4 will affect the velocity of rotation speed. When centrifugal force is regarded as the driving source, the rotation speed is generated by a centrifuge or rotary motor and drives the body 10 to rotate. The speed threshold of the rotation speed depends on the surface tension of the liquid temporarily stored in the first flow channel 221 and the second flow channel 223 (that is, when the centrifugal force on the liquid is greater than surface tension of the liquid, the liquid begins to flow into the first storage section 221b and the second storage section 223b).

To facilitate understanding the principle of the aforementioned speed threshold being implemented in the embodiments, the following description will refer to the schematic diagrams in Fig. 1 to Fig. 3 mentioned above and will be presented in the following Fig. 4, Fig 5, Fig 6 and Fig 7 to Fig 14 respectively.

First of all, Fig. 4 illustrates a flow chart of the centrifugal multi-stage liquid separation device operating method according to some embodiments of the present invention. The centrifugal multi-stage liquid separation device operating method includes following steps. The step (a1) is providing the centrifugal multi-stage liquid separation device abovementioned in Fig. 1. The step (a2) is adding a liquid into the sample adding section 21. The step (a3) is that the body 10 is driven to rotate at a rotation speed, and the liquid with lower density which is separated by centrifugal force will be retained in the first density section 22 and temporary storage section 24 to form a first separated liquid, and the surface tension may retained it in the first flow channel 221, too. On the other hand, the liquid with higher density then enters the second density section 23. As shown in Fig. 3, the step (a4) proceeds after the aforementioned steps has been completed, the liquid with lower density of the first separated liquid is oscillated to climb up the first bending part 221a and to enter the second port f2 by alternatively switching the rotation direction of the body 10 once or multiple times. Finally, the step (a5) is adjusting the rotation speed of the body 10 to rotate at high rotation speed until the liquid with lower density of the first separated liquid breaks the surface tension per se and enters the first storage section 221b shown in Fig. 3 to form a second separated liquid.

The relative density of the liquid primarily depends on the composition of the liquid. For example, when the liquid is blood, the portion with lower density (i.e., the first separated liquid) may be plasma. The portion with higher density may comprise the combination of aggregates of red blood cells, white blood cells and platelets.

The speed threshold is determined by the surface tension of the liquid with lower density of the first separated liquid. In some embodiments, the rotation speed may actually include various and different rotation speeds which may be arbitrarily varied according to the embodiments and detection content in conjunction with the speed threshold, but the present invention is not limited.

Fig. 5 illustrates another flow chart of the centrifugal multi-stage liquid separation device operating method according to some embodiments of the disclosed invention. The centrifugal multi-stage liquid separation device operating method includes following steps. The step (b1) is providing the centrifugal multi-stage liquid separation device. The abovementioned centrifugal multi-stage liquid separation device is as illustrated in Fig. 2. The step (b2) is adding a liquid into the sample adding section 21. The step (b3) is that the body 10 is rotated in one direction via a first rotation speed. The liquid with lower density will be retained in the first density section 22 and temporary storage section 24 to form a first separated liquid via the effect of centrifugal force. Furthermore, the surface tension will be formed at the first flow channel 221 and the second flow channel 223, thus to impede the flow of the first separated liquid. Thereinafter, the portion with higher density will finally enters the second density section 23 as shown in Fig. 3. The step (b4) is that rotation direction of the body 10 is reversely switched and the liquid with lower density of the first separated liquid breaks the restriction of the surface tension per se and enters the second storage section 223b through the second flow channel 223 to form a second separated liquid as shown in Fig. 3. The step (b5) is that the body 10 keeps rotating at the high rotation speed until the liquid remaining in the first density section 22 has been initially separated and settled according to different densities. Finally, the step (b6) is that the rotation direction of the body 10 is switched again, and the liquid with lower density of the remaining first separated liquid breaks the restriction of the surface tension per se and flows into a first storage section 221b (as shown in Fig. 3) through the first flow channel 221 to form a third separated liquid. Please note that in the practical implementation of the disclosed invention, the method may selectively perform the step (b5) after the separation step (b4) depending on the remaining state or conditions of the separation.

The relative amount of the liquid density primarily depends on composition of the liquid. For example, when the liquid is blood, the liquid with lower density (i.e. the first separated liquid) may be plasma. The portion with lower density of the first separated liquid may be the serum mixture. The portion with lower density of the remaining first separation may be serum.

Otherwise, in some embodiments, the rotation speed may be sped up to a speed threshold in the step (b4), allowing the portion with lower density of the first separation liquid breaking the restriction of the surface tension per se through the force generated by the rotation speed. In this case, the rotation speed may also be increased again to over the speed threshold, allowing the portion with lower density of the first separated liquid may more easily to escape form the surface tension limitation per se. At this point, the so-called speed threshold is determined by the surface tension of the portion with lower density of the first separated liquid and the portion with lower density of the remaining first separated liquid. In some embodiments, the rotation speed may actually include various and different driving rotation speed which may be arbitrarily varied according to the embodiments and the detection content in conjunction with the speed threshold, but the present invention is not limited.

Fig. 6 is a flow chart of the centrifugal multi-stage liquid separation device operating method according to some embodiments of the disclosed invention, the method mentioned in the former paragraph comprises the steps as follows. The step (c1) is providing the centrifugal multi-stage liquid separation device. The centrifugal multi-stage liquid separation device used in the current embodiment is illustrated as Fig. 2. The step (c2) is adding the liquid into the sample adding section 21. The step (c3) is that the body 10 is driven to rotate at a rotation speed, causing the liquid with lower density to be retained in the first density section 22, the temporary storage section 24 for forming a first separated liquid via the effect of centrifugal force. On the other hand, the surface tension will be created at the first flow channel 221 and the second flow channel 223 for impeding the flow of the first separation liquid, and the portion with higher density will finally enter the second density section 23. The step (c4) is reducing the rotation speed until the body 10 stopping rotating, and the first separated liquid soaks the second flow channel 223 through capillary action. The step (c5) is restarting and increasing the rotation speed to a speed threshold causing the portion with lower density of the first separated liquid entering a second storage section 223b (as shown in Fig. 3) through the second flow channel 223 to form a second separated liquid. The step (c6) is to keep rotating the body 10 until the remaining first separated liquid stored in the first density section 22 further settles and separates according to different densities per se. The step (c7) is to reversely switch the rotation direction of the body 10 in once, multiple times or continuously switching and make the portion with lower density of the remaining first separated liquid oscillate, climb up and pass through the first bending part 221a. After the soaking is complete, operating the step (c8). The step (c8) is to speed the rotation speed up until the rotation speed is over the rotation speed threshold, allowing the portion with lower density of the remaining first separated liquid to break the restriction of the surface tension per se and to enter the first storage section 221b (as shown in Fig. 3) through the first flow channel 221 to form a third separated liquid.

The rotation speed threshold is determined by the portion with lower density of the first separated liquid and the surface tension of the portion with lower density of the remaining first separated liquid. In some embodiments, the rotation speed may actually include various and different driving rotation speeds which may be arbitrarily varied according to the embodiments and the detection content in conjunction with the speed threshold, but the present invention is not limited.

The inner surface of the second flow channel 223 needs to be made of a hydrophilic material or have been processed by a hydrophilic treatment.

Furthermore, in some embodiments, the method may selectively execute step (c6) that to settle the portion with lower density 63 therein due to the state or conditions of the remaining portion with medium density 62 after the separation step (c5).

In some embodiments, the oscillation method may be selectively performed depending on the actual liquid separation conditions, regardless of the type of the first flow channel 221 or the second flow channel 223 (hydrophilic treatment/non-hydrophilic treatment). The oscillation method provides liquid action and reaction forces such that the liquid may just break through the surface tension limit of the flow channel (first flow channel 221 or second flow channel 223) due to the action force, but does not break through the surface tension limit of the other flow channel (second flow channel 223 or first flow channel 221) due to the reaction force.

Fig. 17 to Fig. 24 are schematic diagrams of the centrifugal multi-stage liquid separation device operating method corresponding to the centrifugal multi-stage liquid separation device according to some embodiments of the present invention. Fig. 7 to Fig. 14 show the movement and distribution of the liquid inside the micro-channel structure 20 in Fig. 2 during operation (i.e., step (c2) to step (c8) in Fig. 6). To facilitate the explanation of the liquid separation process, the portion of the liquid with higher density is referred to as the portion with high density 61, the portion of the liquid with lower density (i.e., the liquid separation in the first stage) is referred to as the portion with medium density 62 and the portion of the liquid separation in the first stage, after sedimentation, with lower density is referred to as the portion with low density 63.

The step (c2) includes a step performed by adding a liquid 60 into the micro-channel structure 20 as illustrated in Fig. 2, resulting in the situation shown in Fig.7. The embodiment of Fig. 7 is referred to the structure shown in Fig. 3, and the structure of Fig. 7 is the same as the structure of Fig. 3. For experiments which have therebefore done the liquid quantification, the micro-channel structure 20 disclosed herein, in conjunction with the application of the sample adding section 21 may selectively add quantification devices/structures according to actual experimental needs.

The step (c3) is that the liquid 60 is sent into the first density section 22 and the second density section 23 under the section of strong centrifugal force, as shown in Fig. 8. In the embodiment shown in Fig.8, the liquid 60 includes the portion with high density 61 and the portion with medium density 62 (for example, the portion with high density 61 may be a blood cell and the portion with medium density 62 may be plasma).

The step (c3) includes that the liquid in the first density section 22 and the second density section 23 is separated under the continuous action of centrifugal force. Based on the principle of buoyancy, the portion with high density 61 will sink to the second density section 23, while the portion with medium density 62 will be floating to the first density section 22, resulting in the distribution as shown in Fig. 9. In Fig. 9, the portion with medium density 62 stored in the first density section 22, the first flow channel 221 and the second flow channel 223 have the same liquid level due to the connecting pipe effect generated by centrifugal force which simulates gravity. The first bending part 221a and the second bending part 223a are mainly configured to form the aforementioned connecting pipe effect.

The step (c4) is that when the rotation speed is reduced until the body 10 stops rotating. As shown in Fig. 10, the portion with medium density 62 of the liquid 60 will gradually soak and fill the second flow channel 223 base on capillary action. Finally, the portion with medium density 62 will stop at the junction of the second flow channel 223 and the second storage section 223b due to the surface tension per se. The aforementioned junction means the fourth port f4 illustrated in the aforementioned implementation state as shown in Fig. 3.

In the step (c4), as shown in Fig. 11, thereby restarting the rotation of body 10 speeding the rotation speed up to a speed threshold to regenerate strong centrifugal force. The regenerated strong centrifugal force may make the portion with medium density 62 break the surface tension per se at the fourth port f4 and flow into the second storage section 223b, forming the first separated liquid. The speed threshold is determined by the surface tension value of the liquid with lower density of the portion with medium density 62 at the fourth port f4.

In Fig. 12, the step (c6) includes keeping the body 10 rotating at a constant speed, causing the remaining portion with medium density 62 (i.e. the liquid with higher density of the portion with medium density 62) in the first density section 22 to settle and separate again due to centrifugal force which simulates gravity. The liquid therein with the lower density is defined as the portion with low density 63.

In Fig. 13, the step (c7) includes that the oscillations are created by repeatedly switching the rotation direction of the body 10, causing the portion with low density 63 to gradually soak and pass through the first flow channel 221. The Fig. 13 is similar to FIG. 10, the portion with low density part 63 will finally remain at the junction of the first flow channel 221 and the first storage section 221b due to the surface tension per se. That is, the portion with low density part 63 will be stopped at the second port f2 of aforementioned implementation shown in Fig. 3. In Fig. 14, when the rotation speed of the body 10 is increased again and the surface tension at the second port f2 is broken by strong centrifugal force, the portion with low density 63 in the first density section 22 will enter the first storage section 221b by evacuation. The aforementioned evacuation is done by siphon effect therefore to form an evacuation flow, and the evacuation flow will be maintained until the potion with low density 63 which is stored in the first density section 22 has been completely evacuated. During the process described above, the portion with high density 61 and the portion with medium density 62 remain in the second density section 23 due to gravity after sedimentation and separation.

As described in the above embodiment, the step (c8) is requiring the rotation speed of the rotating body 10 to be at least greater than the aforementioned speed threshold so that the generated force may overcome the surface tension of the portion with low density 63 per se and making the portion with low density 63 enter the first storage section 221b in Fig. 14. In this embodiment, the first flow channel 221 may be a liquid flow channel that has not been hydrophilized, and the second flow channel 223 may be a liquid flow channel that has been processed by local surface hydrophilization treatment with oxygen plasma. The material of the first flow channel 221 and the second flow channel 223 may be Polymethylmethacrylate (PMMA), Polyethylene Terephthalate (PET), Polycarbonate (PC), Polydimethylsilicon (PDMS), silicone, rubber, plastic or Polymethylmethacrylate (PMMA).

Fig. 15 is a schematic diagram of the centrifugal multi-stage liquid separation device of some embodiments of the present invention. The difference between Fig. 15, Fig. 2 and Fig. 3 is that the centrifugal liquid multi-stage separation device also includes a separation structure 30 connected to the aforementioned second flow channel 223. The separation structure 30 is configured to make the micro-channel structure 20 may directly react the separation liquid with a predetermined reagent. The separation structure 30 illustrated in Fig. 15 includes a separation section 31. The at least one quantitative chamber 311 is used to meter the liquid which is intended to be reacted with the reagent. At least one reaction chamber 313 is used to contain a predetermined reagent and at least one waste solution chamber 315. The separation structure 31 is connected to the quantitative chamber 311. The separation section 31 is connected to the waste solution chamber 315. The quantitative chamber 311 is connected to the reaction chamber 313. The separation section 31, the quantitative chamber 311 and the reaction chamber 313 are mainly arranged from inside to outside according to a center of rotation in the separation structure 30 respectively. The reagent is available in lyophilized form, lyophilized powder, lyophilized pellet or reagent kit. The reagent is reconstituted upon contact with liquid (such as separated liquid).

Please refer to Fig. 2 and Fig. 16. Fig. 16 is a flow chart of the centrifugal multi-stage liquid separation device operating method according to some embodiments of the disclosed invention which comprises the steps as follows. The step (d1) is providing the centrifugal multi-stage liquid separation device. The abovementioned centrifugal multi-stage liquid separation device is as illustrated as the device recited in Fig. 15. The step (d2) is adding the liquid into the sample adding section 21. The step (d3) is the body 10 being driven to rotate at a rotation speed, causing the liquid to be retained in the first density section 22, the temporary storage section 24, the first flow channel 221 and the second flow channel 223 by centrifugal force to form a first separated liquid, and the surface tension which impede the flow of the first separated liquid also be generated at the first flow channel 221 and the second channel 223. The rest portion of the liquid enters the second density section 23. The step (d4) is switching the rotation direction of the body 10 and the rotation speed is reduced to a low speed threshold, allowing the lower density part of the first separated liquid to climb up and enter the separation section 31 and the at least one quantitative chamber 311 through the second flow channel 223 to form a second separated liquid. The rest portion of liquid enters the at least one waste solution tank 315. The step (d5) is speeding the rotation speed up to a high speed threshold to allow the second separated liquid in the at least one quantitative chamber 311 to enter the at least one reaction chamber 313 to perform a reaction. The step (d6) is the body 10 keeping rotating until the remaining liquid in the first density section 22 further settles and separates according to the different densities per se. The step (d7) is direction of the body 10 being switched again, allowing the portion with lower density of the remaining first separated liquid in the step (d4) to enter the first storage section 221b through the first flow channel 221 to form a third separated liquid.

The low speed threshold is determined by the surface tension of the portion with lower density of the remaining first separation (i.e., in this embodiment, the low speed threshold may be 1000 rpm). Of course, in some embodiment, this low speed threshold may also include a plurality of different drive speeds, as described above, as long as the speed value is lower than that speed, but the present invention is not limited. The high speed threshold depends on the surface tension of the liquid in the second separation (for example, in this embodiment, the high speed threshold may be 5,000 rpm) and similarly to the low speed threshold, the high speed threshold may be any combination of drive rotation speeds, as long as the speed value is higher than the low speed threshold.

In addition, in some embodiments, the increase of the rotation speed due to another speed threshold may be done after the rotation direction change, making the first separated liquid easier for the portion with lower density of the liquid in the first separation to overcome the surface tension limit of the first flow channel 221 by the force generated by the rotation speed in the step (d7).

Furthermore, in some possible embodiments, the method may selectively settle the portion with high density of the liquid in the first density section 22 via execution the step (d6) after the reaction step (d5) based on the retaining state or conditions of the first separated liquid in the first density section 22.

Fig. 17 to Fig. 24 are schematic diagrams of the centrifugal multi-stage liquid separation device operating method corresponding to the centrifugal multi-stage liquid separation device according to some embodiments of the disclosed invention. Fig. 7 to Fig. 14 show the movement and distribution of the liquid inside the micro-channel structure 20 in Fig. 15 during operation (i.e., step (d2) to step (d7) in Fig. 6). To facilitate the explanation of the liquid separation process, the portion of the liquid with higher density is referred to as the portion with high density 71, the portion of the liquid with lower density (i.e., the liquid separation in the first stage) is referred to as the portion with medium density 72 and the portion of the liquid separation in the first stage, after sedimentation, with lower density is referred to as the portion with low density 73.

The step (d2) includes adding a liquid 70 into the micro-channel structure 20 in Fig. 15, resulting in the configuration as shown in Fig. 17. For experiments where liquid quantification has already been performed before the experiment, the micro-channel structure 20 disclosed herein, in conjunction with the application of the sample adding section 21 may selectively add quantification devices/structures according to actual experimental needs.

As shown in Fig. 18, the step (d3) is that after the liquid 70 is sent into the first density section 22 and the second density section 23 under the section of strong centrifugal force. In the embodiment shown in Fig. 18, the liquid 70 includes the portion with high density 71 and the portion with medium density 72 (for example, the portion with high density 71 may be a blood cell and the portion with medium density 72 may be plasma).

The step (d3) includes that the liquid in the first density section 22 and the second density section 23 will be separated under the continuous action of centrifugal force. Based on the principle of buoyancy, the portion with high density 71 will sink down to the second density section 23, while the portion with medium density 72 will float upon to the first density section 22, resulting in the distribution, as shown in Fig. 19. In Fig. 19, the first density section 22 and the portion with medium density 72 in the first flow channel 221 and the second flow channel 223 have the same liquid level due to the connecting pipe effect generated by centrifugal force which simulates gravity. The first bending part 221a and the second bending part 223a are mainly configured to form the aforementioned connecting pipe effect.

As shown in Fig. 20, the step (d4) is that when the direction of the body 10 is switched and the rotation speed is reduced to a low speed threshold. The portion with medium density 72 of the liquid 70 will start to climb up, and enter the distribution section 31 and the quantitative chamber 311 through the second flow channel 223, respectively. Finally, the liquid 70 fills each quantitative chamber 311 and stays at the junction of the quantitative chamber 311 and the reaction chamber 313 based on the surface tension of the liquid 70 per se. At this time, the rest of the portion with medium density 72 which is not used for filling will enter the waste solution chamber 315. In the step (c4), the abovementioned low speed threshold is determined by surface tension value of the portion with medium density 72 stopped in the interface of the second flow channel 223.

As shown in Fig. 21, the step (d5) includes adjusting the aforementioned rotation speed to a high speed threshold to regenerate a strong centrifugal force. The portion with medium density 72 in the quantitative chamber 311 utilizes the force generated by this strong centrifugal force to overcome the surface tension of the liquid at the interface and enter the reaction chamber 313 to perform a reaction. The reaction is carried out in a suitable reagent based on the properties of the liquid 70. The reagent may be provided in the form of lyophilized, lyophilized powder or reagent package. The liquid 70 is pre-contained in reaction chamber 313. It should be noted that the high speed threshold of step (d5) depends on the surface tension value of the portion with medium density 72 at the interface.

In Fig 22, the step (d6) includes keeping the body 10 rotating at a constant speed, causing the rest of the portion with medium density 72 in the first density section 22 to settle and separate again due to centrifugal force which simulates gravity where the part with the lower density is defined as the portion with low density 73.

As shown in Fig. 23. In Fig. 24, the step (d7) is similar to Fig. 20, the rotation direction of body 10 is switched again. Finally, the portion with low density 73 will remain at the junction of the first flow channel 221 and the first storage section 221b due to surface tension. When the rotation speed of the body 10 is increased again, the portion with low density 73 will break through the surface tension at the junction of the first flow channel 221 and the first storage section 221b based on the force generated by the strong centrifugal force flow into the first storage section 221b. The portion with low density 73 forms a evacuation flow through the siphon effect until the portion with low density 73 in the first density section 22 is evacuated. During the process described above, the portion with high density 71 in the second density section 23 and the portion with medium density 72 in the separation structure 30 are retained therein due to the gravity.

As is understood by a person skilled in the art, the foregoing preferred than limiting of the present invention. It is intended to cover various modifications and similar arrangements included within the spirit and scope of the appended claims, the scope of which should be accorded the broadest interpretation so as to encompass all such modifications and similar structure. While the preferred embodiment of the invention has been illustrated and described, it will be appreciated that various changes can be made therein without departing from the spirit and scope of the invention.