Device, device array and method for biochemical reactions

Abstract

The present disclosure relates to devices, arrays of devices, and methods for biochemical reactions. The device comprises a reaction unit. The reaction unit comprises a reaction cavity; the grooves are used for accommodating reagents and are positioned in the reaction cavity; and at least one groove cover disposed in the reaction chamber, and for at least one groove of the plurality of grooves, the at least one groove cover is configured to switch between closing and opening the at least one groove under a driven condition. In this way, complex multi-step reactions (such as nucleic acid extraction, amplification and the like) can be automatically completed under the condition that external pump valve intervention is not needed.

Description

Technical Field

[0001] This disclosure relates to the field of biotechnology. In particular, this disclosure relates to apparatus, arrays of apparatus, and methods for biochemical reactions. Background Technology

[0002] With the rapid development of molecular biology, clinical diagnostics, and drug development, higher demands are being placed on the efficiency, cost, and portability of biochemical reaction analysis. Against this backdrop, automated integration technology for small-volume biochemical reactions has emerged and become a cutting-edge direction in modern analytical science. This technology aims to integrate the cumbersome, manually operated, multi-step biochemical processes of traditional laboratories onto a miniaturized, automated platform (typically based on microfluidic chips or microplate structures), thereby achieving high-throughput, rapid, and accurate analysis of trace samples (microliters to nanoliters). However, under conditions of small volumes and multi-step sequential operations, existing platforms generally face challenges such as: evaporation and volume / concentration drift during thermal cycling or heating; non-specific adsorption of samples / reagents onto the container walls leading to a decrease in effective concentration; and system complexity and reliability issues arising from reliance on complex pumps, valves, or thermal triggering elements for sequential sample addition.

[0003] This technology is primarily applied to key scenarios such as nucleic acid amplification (e.g., PCR, isothermal amplification), enzymatic reactions (e.g., enzyme kinetic analysis), and library construction (e.g., methylation transformation, library construction, library hybridization, library capture). These applications typically involve multi-step, sequential liquid handling operations, including sample introduction, sequential reagent addition, droplet mixing, incubation, and final detection. In such processes, achieving reliable sequential release / addition without relying on complex external pumps and valves, effective mixing without compromising liquid phase stability, and stable and reproducible point-to-point temperature control in the target reaction region are core technological requirements for improving the consistency, reproducibility, and array-based scalability of small-volume biochemical reactions. Summary of the Invention

[0004] In a first aspect of the embodiments of this disclosure, an apparatus for a biochemical reaction is provided, comprising: a reaction unit including a reaction chamber; a plurality of recesses for receiving reagents and located within the reaction chamber; and at least one recess cover disposed within the reaction chamber, and configured to switch between closing and opening at least one recess when driven; and a driving device for driving at least one recess cover.

[0005] In a second aspect of the embodiments of this disclosure, an array of apparatuses for a biochemical reaction is provided, comprising: a plurality of reaction units, each of the plurality of reaction units being configured according to the reaction units in the apparatus for a biochemical reaction of the first aspect of this disclosure; and a driving unit being configured according to the driving device in the apparatus for a biochemical reaction and for driving the plurality of reaction units.

[0006] In a third aspect of the embodiments of this disclosure, a biochemical reaction method is provided, comprising: adding immiscible and non-reactive first-type liquid, second-type liquid, and third-type liquid to a reaction chamber, wherein the first-type liquid has a first density greater than the second-type liquid and less than the third-type liquid; adding a sample to the reaction chamber, wherein the sample belongs to the first-type liquid and mixes with the first-type liquid in the reaction chamber; and sequentially adding multiple reagents to the reaction chamber, wherein the multiple reagents belong to the first-type liquid and mix with the first-type liquid in the reaction chamber, to perform a biochemical reaction.

[0007] It should be understood that the description in the Summary of the Invention section is not intended to limit the key or essential features of the embodiments of this disclosure, nor is it intended to restrict the scope of this disclosure. Other features of this disclosure will become readily apparent from the following description. Attached Figure Description

[0008] To better understand the above and other objects, features, advantages, and functions of this disclosure, reference can be made to the preferred embodiments shown in the accompanying drawings. Like reference numerals in the drawings refer to like parts. Those skilled in the art should understand that the drawings are intended to schematically illustrate preferred embodiments of this disclosure and are not intended to limit the scope of this disclosure; the parts in the drawings are not drawn to scale.

[0009] Figure 1 A schematic diagram of an example apparatus array for a biochemical reaction according to an embodiment of the present disclosure is shown;

[0010] Figure 2 A schematic diagram of a reaction unit of an example apparatus for a biochemical reaction according to an embodiment of the present disclosure is shown;

[0011] Figures 3A to 3C A schematic cross-sectional view of several components of an example apparatus for a biochemical reaction according to an embodiment of the present disclosure is shown;

[0012] Figure 4 A schematic flowchart of an example method for a biochemical reaction according to embodiments of the present disclosure is shown; and

[0013] Figures 5A to 5D A schematic diagram of an example process used for a biochemical reaction is shown. Detailed Implementation

[0014] Various embodiments will now be described with reference to the accompanying drawings, wherein similar reference numerals are used throughout to denote similar elements. In the following description, numerous specific details are set forth for purposes of explanation in order to facilitate a thorough understanding of one or more embodiments. However, it may be apparent in some or all cases that any of the embodiments described below can be practiced without employing the specific design details described below. In other instances, well-known structures and devices are illustrated in block diagram form to facilitate the description of one or more embodiments. A simplified overview of one or more embodiments is given below to provide a basic understanding of the embodiments. This overview is not an exhaustive summary of all contemplated embodiments, is not intended to identify key or essential elements of all embodiments, nor is it intended to define the scope of any or all embodiments.

[0015] References to “embodiment” or “one embodiment” within the framework of this description are intended to indicate that a particular configuration, structure, or feature described with respect to an embodiment is included in at least one embodiment. Therefore, phrases such as “in an embodiment” or “in one embodiment” that may appear at one or more points in this description do not necessarily refer to the same embodiment. Furthermore, in one or more embodiments, particular constructions, structures, or features may be combined in any suitable manner.

[0016] As discussed above, the automated integration technology for small-volume biochemical reactions has attracted much attention. However, automating a series of operations within a microscale space presents numerous severe technical challenges. These include suppressing evaporation and volume drift, reducing the impact of non-specific adsorption on trace components by container walls, completing sequential sample addition, mixing, and temperature control without introducing complex valves and pumps, and supporting parallel high-throughput.

[0017] To address these challenges, various solutions for suppressing evaporation and automating processes have been developed in related technologies. For example, one evaporation suppression solution is microscale operation using an oil-phase coating. This involves using an immiscible oil phase to cover aqueous droplets in an open or semi-open microfluidic structure to reduce evaporation and lower the risk of cross-contamination. However, a single oil phase layer cannot completely isolate the reaction phase from the equipment; some reaction phase will still adhere to the equipment, resulting in reaction phase loss. Furthermore, an automated process solution is pump-free or valve-free mechanical alignment-based sequential sample dispensing. For example, the relative sliding of upper and lower substrates connects the cavities in a preset order, enabling sequential release, addition, and multi-step reaction integration of reagents. In such related technologies, two stacked substrates can be pre-fabricated with cavities and microfluidic paths for accommodating reagents or samples. By precisely sliding the two substrates relative to each other, the alignment of the cavities is changed, allowing the fluid to switch between "isolation" and "connection / mixing" modes. However, such related technologies suffer from structural complexity and low reliability, especially when expanded, the complexity of actuators and controls increases dramatically, leading to more potential failure points. Furthermore, two-dimensional sliding structures typically struggle to achieve precise temperature control and safe mixing at restricted angles within the same cavity of the "target reaction layer."

[0018] In summary, current technologies lack a solution that can effectively address the aforementioned challenges. Most existing platforms either have shortcomings in preventing evaporation and adsorption, rely on relatively complex external control systems making true integration difficult, or encounter bottlenecks in throughput improvement. Therefore, developing a small-volume automated biochemical reaction technology platform that can achieve low evaporation, low adsorption, simple fluid control, and high throughput capacity under the premise of high-density integration has become an urgent technological need in this field.

[0019] In view of this, embodiments of the present disclosure provide a highly integrated biochemical reaction system. The biochemical reaction system includes a reaction chamber within a main container for carrying and completing the biochemical reaction. Reagent mixing and the reaction can both take place within this chamber. Multiple recesses for pre-storing different reagents are provided within the reaction chamber. Above the multiple recesses, recess covers are provided that can selectively open or close the recesses below them. The recess covers switch between different positions under the drive of a driving device, thereby achieving the sequential and controllable release of multiple reagents within the reaction chamber, thus completing a multi-step biochemical reaction.

[0020] According to embodiments of this disclosure, a three-phase reaction system can be provided in the reaction chamber, namely, a stable, layered reaction system formed from top to bottom by three types of liquids with different densities and immiscibility, under static or controlled conditions. The first type of liquid is a hydrophilic or water-soluble reaction phase; the second type of liquid is an upper layer liquid with lower density that is immiscible and non-reactive with the first type of liquid; and the third type of liquid is a lower layer liquid with higher density that is immiscible and non-reactive with the first two types. In this reaction system, the reaction phase is located between the other two phases, and the reagents located in the grooves are also part of the reaction phase. When the groove cover closes at least one groove, the reagent in the corresponding groove is isolated from the main space of the chamber. When the groove cover moves under a drive and opens at least one groove, the opening aligns with the corresponding groove to release the reagent. The released reagent automatically enters the intermediate layer under the influence of the density difference and merges with the reaction phase.

[0021] In this way, complex multi-step reactions (such as nucleic acid extraction and amplification) can be automatically completed without external intervention. The device and method disclosed herein utilize a three-phase layered double-sided sandwich structure to suppress evaporation and reduce non-specific adsorption, combined with a notched grooved cap to achieve valveless sequential sample addition, thereby improving reaction consistency and reproducibility.

[0022] Furthermore, multiple reaction units can be multiplexed into an array using a single drive and / or a single temperature control, thereby enabling parallel operation of multiple units. This reduces system complexity and potential failure points, while improving reaction stability and repeatability.

[0023] The following will combine Figures 1 to 5D This will be used to explain the operation process and principle of the device and method disclosed herein. Figure 1 A schematic diagram of an example apparatus array 10 for a biochemical reaction according to an embodiment of the present disclosure is shown. Figure 1 As shown, the device array 10 for biochemical reactions includes multiple reaction components 102, namely reaction component 102-1, reaction component 102-2, and reaction component 102-3 (which may be referred to individually or collectively as reaction components 102). Each reaction component 102 includes a temperature control unit 104, a reaction unit 106, and a base 108. Furthermore, the device array 10 also includes a drive unit 110 for driving the multiple reaction units. In some embodiments, the device is configured to perform multi-step, sequential biochemical processes and reactions within the same chamber.

[0024] In the illustrated embodiment, the reaction unit 106 can accommodate a three-phase system composed of three immiscible and non-reactive liquids of different densities, which, after standing, stably separates into layers from top to bottom, and complete the reaction process. The main body of the reaction unit 106 has a structure with a larger lower cross-sectional area and a smaller upper cross-sectional area. The bottom of the reaction unit 106 may have multiple recessed reagent compartments. Reagents are sealed inside the reagent compartments. The top of the reaction unit 106 may have a protrusion for engaging with the recess of the temperature control unit 104 to maintain the stability of the reaction unit 106. The reagent compartment cover is located inside the reaction unit 106 and is used to selectively close part or all of the reagent compartments, i.e., selectively open the corresponding recess. For example, the recess cover may have a notch; when the notch rotates to the top of the target reagent compartment, the contents of that compartment are released, while when the notch does not coincide with the reagent compartment, the reagent compartment remains sealed and does not release. The reaction unit 106 may also have a first gear 118 connected to the internal recess cover. The first gear 118 is connected to the reagent chamber cover via a receiving shaft that passes through a through hole at the bottom of the reaction unit 106. In some embodiments, a dynamic sealing member may be provided between the receiving shaft and the through hole to prevent leakage of liquid from the chamber.

[0025] The driving device 110 includes a drive motor 112, a second gear 114 connected to the output shaft of the drive motor 112, and a rack 116. The drive motor 112 drives the rack 116 to move linearly. The rack 116 meshes with the second gear of the reaction unit of the plurality of reaction components 102, driving the second gear to rotate at a preset angle, and driving the groove cover to release at a fixed angle via the receiving shaft. In some embodiments, the driving device 112 can also drive the groove cover / stirring plate to make a small reciprocating angular displacement within the avoidance angle range to perform interfacial mixing.

[0026] The temperature control unit 104 is provided with a through hole. The smaller cross-section of the upper part of the reaction unit 106 can fit into this through hole, facilitating positioning and heat conduction / insulation arrangement. The temperature control unit 104 may also have a recess that engages with the protrusion on the top of the reaction unit to prevent the reaction chamber from rotating when the gear rotates. The working area of ​​the temperature control unit 104 is aligned with the interface of the three-phase system, providing point-to-point temperature control for the reaction phase located in the middle layer, ensuring that the reaction phase in the middle layer reacts at a preset temperature.

[0027] according to Figure 1 In the illustrated embodiment, the temperature control unit 104, reaction unit 106, and drive device, when assembled, form a coaxial collaborative relationship of "drive-alignment-temperature control," ensuring the synchronous realization of sequential reagent release, interfacial mixing within the avoidance angle range, and stable temperature control. A single drive unit links several reaction units via a rack and pinion system, and the temperature control unit simultaneously serves multiple reaction units, thereby achieving high-throughput, scalable parallel reactions without the need for external pumps or valves or the linear increase of valves / pumps / control channels.

[0028] In the device array according to embodiments of this disclosure, multiple reaction units are arranged linearly or in a matrix and fixed on a common support and positioning base. A temperature control unit's working area is positioned above each reaction unit to cover its corresponding location. A drive unit (drive motor and rack) is arranged in the lateral region of the reaction unit array, such that the rack meshes with the gears of each reaction unit individually or through segmented meshing to achieve linkage, thereby forming a parallel structure of a single drive and multiple reaction chambers. This arrangement helps maintain angular zero-position consistency and operational synchronization of each unit under array conditions.

[0029] The single-drive, multi-cavity transmission chain consists of a drive motor-rack system that distributes outputs along the array direction to multiple reaction units. Each reaction unit's gear-receiving shaft-reagent compartment cover / stirring plate executes a sequence of actions—"alignment release / avoidance angle mixing"—in a time-programmed, polling or grouped manner. During assembly, each reaction unit uses positioning features (such as the smaller cross-section of the upper body aligning with the temperature control unit's through-hole, and the fit of protrusions and grooves) as a reference to ensure the gear and rack meshing clearance is consistent with the angular zero position, thus guaranteeing the repeatability of the notch-reagent compartment angle position for each unit. Mixing of each reaction unit in the array is performed only within its avoidance angle range; when the drive sequence reaches a unit for release, the remaining units are in the safety angle zone, avoiding notch overlap and accidental release across units (similar to the accidental release suppression logic in Example 3, now extended to multi-cavity timing). The temperature control unit is equipped with one or more through-holes that align with the small cross-section of the upper body of each reaction unit to achieve precise array positioning. The working area of ​​the temperature control unit is aligned with the interface of the three-phase system, allowing simultaneous control of the reaction phases of several reaction units within a preset temperature range. The protrusions on the top of each reaction unit engage with the grooves of the temperature control unit, preventing relative rotation of individual units in the array due to transmission disturbances, which would affect alignment accuracy and reversal repeatability. When the array is driven by polling, the temperature control unit maintains uniform, fixed-point temperature control. When the array is driven by grouped parallel processes, the coverage area of ​​the corresponding group of the temperature control unit maintains temperature consistency to reduce differences in reaction endpoints. Under these conditions, the released first-type liquid reagent automatically enters the intermediate layer and merges with the reaction phase under the influence of density difference, further improving the consistency of steps and the repeatability of results during array operation.

[0030] In some embodiments, a polling strategy can be used for reagent release control. In this strategy, the drive unit sequentially aligns with the target reagent chambers of each reaction unit according to chamber position and performs release / mixing. This strategy is simple to control and easily ensures minimal mechanical and thermal interference between adjacent units. Alternatively, a grouped parallel strategy can be used. In this strategy, the array can be divided into two or more non-interfering groups, with synchronous actions within the same group and phase-staggered operations between groups; this is suitable for scenarios with higher throughput and cycle time requirements. Under both strategies, reaction units not currently aligned are kept in a safe corner area to avoid accidental release.

[0031] In some embodiments, multi-gear rack segmented linkage can be implemented. In such embodiments, under the same drive motor output, parallel or series-connected rack segments are configured to mesh with reaction units in different columns or rows, thereby shortening the polling cycle in a large array. The segmented linkage does not change the alignment release and mixing mechanism of a single cavity.

[0032] In some embodiments, the temperature control area may include multiple windows. The temperature control unit is provided with multiple through-hole windows to match the array layout. Each window mates with the upper small cross-section of the corresponding reaction unit to maintain alignment and anti-rotation consistency (the same protrusion-groove fit as the single cavity). In some embodiments, the through-hole and groove of the temperature control unit can be used as the primary assembly reference, and the position of the drive gear rack as the secondary assembly reference, to ensure the uniformity of the angular zero position and the repeatability of the alignment accuracy of the entire array. Preferably, the temperature control working area is aligned with the interface boundary of the three-phase system to implement fixed-point temperature control, and can simultaneously cover multiple reaction units.

[0033] Figure 1 The shown reaction component 102 can be combined with the drive device 110 to form an apparatus 100 for a biochemical reaction according to an embodiment of this disclosure. The following will be combined with... Figures 2 to 3C To describe the structure of device 100. Figure 2 A schematic diagram of a reaction unit 106 of an example apparatus for a biochemical reaction according to an embodiment of the present disclosure is shown. Figure 2As shown, the reaction unit 106 includes a reaction unit body 202. A reaction chamber 204 is formed inside the reaction unit body 202. The reaction unit body 202 includes a circular bottom 206. The bottom 206 includes a bottom surface adjacent to the reaction chamber 204. The bottom surface constitutes the bottom of the reaction chamber 204. The reaction unit 106 also includes a first sidewall segment 208 extending from the bottom 206 in a direction perpendicular to the bottom surface, and a second sidewall segment 210 extending from the first sidewall segment 208 in the vertical direction to the opening of the reaction unit body 202. The first inner diameter of the first sidewall segment 208 is larger than the second inner diameter of the second sidewall segment 210. In some embodiments, the inner diameter of the sidewall segment may be the average inner diameter of the entire segment. In some embodiments, the opening of the reaction chamber is sealed with a puncturable soft rubber stopper for sealing and sample loading.

[0034] A plurality of grooves 212 are provided on the bottom surface of the bottom 206, including grooves 212-1, 212-2, 212-3, 212-4, 212-5, and 212-6. Sealing rings can be provided at the edges of the grooves to seal the pre-filled reagents when not opened. At least one groove cap is also provided above the multiple grooves, for example, one groove cap for each groove or one groove cap for multiple grooves. Figure 2 In the illustrated embodiment, at least one recessed cover 214 is a single recessed cover 214. The recessed cover 214 is located inside the reaction unit body 202 and is used to selectively close part or all of the recesses 212. For example, for at least one of the plurality of recesses 212, at least one recessed cover 214 is configured to switch between closing and opening at least one recess when driven, i.e., at least one recessed cover 214 can close or open any one recess. For example, a recessed cover moves between a position closing all recesses and a position opening at least one of the plurality of recesses. The recessed cover 214 includes an opening (also referred to as a notch) that releases reagent from a target recess when the opening rotates over it, i.e., when the opening aligns with the target recess. When the opening is misaligned with the recess, the recess remains sealed and does not release reagent. Furthermore, the recessed cover 214 includes a plurality of stirring plates 216. The plurality of stirring plates 216 extend vertically from the recessed cover 214 toward the reaction chamber 204. In some embodiments, the recessed cover is connected to a first gear via a receiving shaft to achieve aligned release at a predetermined angle and mixing at an avoidance angle.

[0035] During the reaction, a three-phase system is first formed in the reaction chamber 204 of reaction unit 106. The three-phase reaction system consists of three types of immiscible liquids with different densities, which form stable stratification from top to bottom under static or controlled conditions. For example, the first type of liquid 220 (reaction phase) is a liquid with moderate density in the three-phase system, with a density of 0.9–1.1 g / cm³. 3It is a hydrophilic or water-soluble medium used to hold samples and reagents and as a medium for the reaction (“reaction phase / reaction system”). The second type of liquid 218 is the liquid with the lowest density in the three-phase system, less than that of the first type of liquid. In some embodiments, the density of the second type of liquid 218 may be less than 0.9 g / cm³. 3 The density may be lower than the lower limit of the density range of the first type of liquid 220. The second type of liquid 218 is insoluble in water, immiscible with the first type of liquid, and does not react with the first type of liquid 218. The third type of liquid 222 is the densest liquid in the three-phase system, with a density greater than that of the first type of liquid 220 and the second type of liquid 218. In some embodiments, the density of the third type of liquid 222 may be greater than 1.1 g / cm³. 3 The density may be higher than the upper limit of the density range of the first type of liquid 220; the third type of liquid 222 is immiscible with the first and second type of liquids and does not react with them. Under a gravitational field, the three types of liquids stably separate into an upper layer of the second type of liquid 218, an intermediate layer of the first type of liquid 220, and a lower layer of the third type of liquid 222. The first type of liquid 220 can exist as a continuous phase in the intermediate layer, or it can exist as discrete droplets under specific conditions, located between the second and third type of liquids.

[0036] After the three-phase system is formed in reaction chamber 204, the sample can be added to reaction chamber 204 of reaction unit 106 by piercing the soft rubber stopper with a puncture needle. The sample belongs to the first type of liquid and automatically enters and remains in the intermediate layer due to the density difference. Then, the drive unit controls the movement of the groove cover according to the program to release the reagent. The released reagent belongs to the first type of liquid and merges with the sample in the first type of liquid after entering the intermediate layer, forming a reaction system together. The drive unit drives the stirring plate to perform reciprocating angular displacement to disturb the intermediate layer and achieve homogenization of the reaction system. The angular displacement used for homogenization is an avoidance angle, that is, avoiding the position where the notch of the cover coincides with the reagent chamber that has not yet released the reagent, to prevent accidental release during the homogenization process. In addition, the temperature control unit performs fixed-point temperature control at the interface boundary to keep the reaction phase at the preset temperature to control the biochemical reaction process. After the sequential release, merging and homogenization of the sample and reagent are completed, the reaction is carried out in the intermediate layer at the preset temperature until the predetermined endpoint conditions are reached (such as the completion of the time / step set by the program).

[0037] exist Figure 2In the illustrated embodiment, the reaction phase composed of the first type of liquid 220 is located in the narrower second sidewall section 210 of the reaction unit body 202, making temperature control by the temperature control unit easier. In this configuration, the working area of ​​the temperature control unit can be aligned with the interface between the three phases, allowing for targeted temperature control of the reaction phase located in the intermediate layer. Furthermore, a large amount of the third type of liquid exists between the reagent storage recess and the reaction phase, preventing the reagent stored in the recess from being affected by the temperature control unit. This device structure ensures stable three-phase stratification, and the temperature control unit's alignment with the interface ensures the reaction occurs in a controlled region, improving the selectivity and reproducibility of the reaction. The sealing ring and lid notch of the reagent compartment enable targeted and sequential release. Simultaneously, the stirring plate performs interface-adjacent disturbance within the avoidance angle range to prevent accidental release from unordered recesses during mixing.

[0038] Figure 3A A schematic cross-sectional view of an example reaction unit 106 for a biochemical reaction according to an embodiment of the present disclosure is shown. Figure 3A As shown, the reaction unit 106 includes a reaction unit body 202. A reaction chamber 204 is formed inside the reaction unit body 202. The reaction unit body 202 includes a circular bottom 206. The bottom 206 includes a bottom surface adjacent to the reaction chamber 204. The bottom surface constitutes the bottom of the reaction chamber 204. The reaction unit 106 also includes a first sidewall segment 208 extending from the bottom 206 in a direction perpendicular to the bottom surface, and a second sidewall segment 210 extending from the first sidewall segment 208 in the vertical direction to the opening of the reaction unit body 202. The first inner diameter of the first sidewall segment 208 is larger than the second inner diameter of the second sidewall segment 210. Furthermore, a soft rubber stopper 302 (perforable for sample addition) is provided at the opening for sealing the reaction chamber 204.

[0039] A plurality of grooves 212 are provided on the bottom surface of the bottom 206. A groove cover 214 is also provided above the plurality of grooves. The groove cover 214 is located inside the reaction unit body 202 and is used to selectively close some or all of the grooves 212. The groove cover 214 is configured to open or close at least one of the plurality of grooves 212 when driven. The groove cover 214 includes an opening 306. When the groove cover 214 closes the plurality of grooves 212, the opening 306 is offset from all the grooves in the plurality of grooves 212, and when the groove cover opens at least one of the grooves 212, the opening 306 is aligned with the corresponding groove in the plurality of grooves 212. That is, when the opening 306 rotates above the target groove, the opening 306 is aligned with the target groove, and the target groove is opened. When the opening 306 is offset from the groove, the misaligned groove remains sealed. Furthermore, the groove cover 214 also includes a plurality of stirring plates 216. The plurality of stirring plates 216 extend vertically from the groove cover 214 toward the reaction chamber 204. Figure 3AAs shown, the groove cover 214 also includes a receiving shaft 304. An extension of the receiving shaft 304 passes through a through-hole in the bottom 206 and connects to the first gear 118. The first gear 118 is coupled to and driven to rotate by the drive device 110. During the mixing stage, the stirring plate 216 reciprocates within an avoidance angle range to balance mixing efficiency and prevent accidental release.

[0040] Figure 3B A schematic cross-sectional view of an example reaction unit body 202 for a biochemical reaction according to an embodiment of the present disclosure is shown. Figure 3B As shown, the bottom 206 includes a through hole 310 in its center to allow the receiving shaft 304 of the recessed cover 214 to pass through. A sealing ring 312 is provided at the edge of the recessed cover adjacent to the through hole 310. The sealing ring 312 is positioned between the recessed cover and the through hole 310, thereby sealing the through hole 310 and preventing the reaction liquid from entering the through hole 310. Similarly, a sealing ring 308 is also provided at the edge of each of the plurality of recesses 212, the sealing ring 308 engaging with the lower surface of the recessed cover 214 to seal the corresponding recess in case of misalignment.

[0041] Figure 3C A schematic cross-sectional view of an example recessed cap assembly for a biochemical reaction according to an embodiment of the present disclosure is shown. Figure 3C As shown, the recessed cover 214 includes a generally disc-shaped body 314. An opening 306 is provided on the body 314. The opening 306 is a fan-shaped notch in the disc-shaped body 314, thereby allowing the position of the opening 306 to be controlled by the rotation angle of the drive device. The fan-shaped shape facilitates the determination of the rotation control angle. The body 314 is disposed inside the reaction chamber 204. When the opening 306 rotates above the target recess, the corresponding reagent is released, and the misaligned reagent compartment remains sealed. A stirring plate 216 is also included above the body 314. The stirring plate 216 is configured to reciprocate under the drive of the body 314 for interfacial mixing of the intermediate layer of the first type of liquid. Preferably, the angle range of the reciprocating movement is defined as an avoidance angle range to prevent the opening 306 from coinciding with the position of the unreleased recess. The bottom surface of the stirring plate 216 is connected to a receiving shaft 304. The other end of the receiving shaft 304 is connected to a first gear 118. The first gear 118 is used to mesh with the gear rack to realize a compound action of fixed angle positioning and avoidance angle mixing according to the program.

[0042] Figure 4 A schematic flowchart of an example method 400 for a biochemical reaction according to an embodiment of this disclosure is shown. Figure 4As shown, at position 402, immiscible and non-reactive liquids of type I, type II, and type III are added to the reaction chamber. The first density of type I liquid is greater than the second density of type II liquid and less than the third density of type III liquid. After standing, the liquids are layered from top to bottom as follows: type II liquid (top) — type I liquid (middle, reaction phase) — type III liquid (bottom).

[0043] exist Figure 1 and Figure 2 In the illustrated embodiment, prior to step 402, method 400 may further include fixing the reaction unit within the temperature control unit, such that the second sidewall section of the reaction unit body fits into the through hole of the temperature control unit, and the top protrusion of the positioning body engages with the groove of the temperature control unit to form an anti-rotation mechanism. Afterwards, a three-phase stratification of second-type liquid (upper), first-type liquid (middle), and third-type liquid (lower) can be established within the reaction chamber, and the system is allowed to stand until the interfaces are clear and stable. In this embodiment, the three-phase reaction system consists of three immiscible liquids of different densities, forming a stable top-to-bottom stratification under standing or controlled conditions. For example, the first-type liquid 220 (reaction phase) is a liquid with a medium density in the three-phase system, with a density of 0.9–1.1 g / cm³. 3 It is a hydrophilic or water-soluble medium used to hold samples and reagents and as a medium for the reaction (“reaction phase / reaction system”). The second type of liquid 218 is the liquid with the lowest density in the three-phase system, less than that of the first type of liquid. In some embodiments, the density of the second type of liquid 218 may be less than 0.9 g / cm³. 3 The density may be lower than the lower limit of the density range of the first type of liquid 220. The second type of liquid 218 is insoluble in water, immiscible with the first type of liquid, and does not react with the first type of liquid 218. The third type of liquid 222 is the densest liquid in the three-phase system, with a density greater than that of the first type of liquid 220 and the second type of liquid 218. In some embodiments, the density of the third type of liquid 222 may be greater than 1.1 g / cm³. 3 The density may be higher than the upper limit of the density range of the first type of liquid 220; the third type of liquid 222 is immiscible with the first and second type of liquids and does not react with them. Under a gravitational field, the three types of liquids stably separate into an upper layer of the second type of liquid 218, an intermediate layer of the first type of liquid 220, and a lower layer of the third type of liquid 222. The first type of liquid 220 can exist as a continuous phase in the intermediate layer, or it can exist as discrete droplets under specific conditions, located between the second and third type of liquids.

[0044] Method 400 can also include reagent pre-storage and sealing checks. For example, the first type of liquid reagent to be added sequentially can be pre-stored in multiple grooves at the bottom of the reaction chamber, sealed by groove covers, and then checked. The check may include verifying that the reagent compartment edge sealing ring fits properly with the compartment cover and that there is no leakage when misaligned. The check may also include verifying the reliability of the dynamic seal at the receiving shaft and the through hole. The check may also include ensuring that the gear and gear rack meshing clearance is within a preset range.

[0045] At position 404, the sample is added to the reaction chamber. The sample belongs to type I liquid and mixes with type I liquid in the reaction chamber. The sample is added...

[0046] The sample (belonging to the first type of liquid) is added to the reaction chamber through a puncture needle piercing the top soft rubber stopper. Due to the density difference, the sample spontaneously enters the intermediate layer and reacts with the existing first type of liquid in the phase-coupling layer. The puncture needle is then removed, and the soft rubber stopper is resealed.

[0047] The method further includes mixing using multiple stirring plates (216) in the reaction chamber (204).

[0048] First stage: mixing (premixing)

[0049] The drive unit drives the gear to make a small reciprocating angular displacement, and the stirring plate performs interface proximity disturbance within the avoidance angle range, so that the sample and reaction phase in the intermediate layer achieve preliminary homogenization; at this time, the notch of the cover does not coincide with any "unordered reagent compartment".

[0050] At position 406, multiple reagents are added sequentially to the reaction chamber. Here, these reagents are of the first type of liquid and mix with the first type of liquid in the reaction chamber to carry out a biochemical reaction. Figure 1 and Figure 2 In the illustrated embodiment, at least one recessed cover can be driven by the drive unit 110 of the apparatus 100 for the biochemical reaction, causing a plurality of recesses 212 to be opened sequentially, thereby releasing reagents from the corresponding recesses of the plurality of recesses 212. Furthermore, during the execution of the biochemical reaction process, the temperature control unit of the apparatus for the biochemical reaction can also be used to perform point-controlled temperature control on the first type of liquid in the reaction chamber.

[0051] In some embodiments, the process of performing a biochemical reaction may include sequential reagent release and layer-by-layer fusion. For example, one or more cycles of "alignment-release-layer-mixing" can be performed according to a preset program. In the alignment stage, a drive device can drive a gear at a preset angle to align the opening of the groove cap with the target groove. In the release stage: the corresponding groove opens, and the reagent (first type of liquid) is released. In the layer-by-layer stage, the released reagent can automatically enter the intermediate layer under the action of density difference and orientedly fuse with the reaction phase. In the mixing stage, a reciprocating angular displacement disturbance within the avoidance angle range can be performed to complete the interface proximity mixing of this step. In the reset stage, the gear retracts to the safety angle area to avoid forming a gap with the unordered reagent compartment. The above steps can be repeated sequentially for multiple reagent compartments according to the program until all the set sample addition sequences are completed.

[0052] Throughout the entire cycle of "alignment-release-co-layering-mixing," point-to-point temperature control can be performed. For example, the working area of ​​the temperature control unit can be kept aligned with the three-phase interface boundary to implement point-to-point temperature control on the intermediate reaction phase. The temperature control setting can be maintained or adjusted in stages according to a preset program to ensure that the target biochemical reaction proceeds to the predetermined endpoint (such as when time is reached or the signal reaches a threshold) under a stable temperature field.

[0053] In some embodiments, a portion of the mixing step may be incorporated into a short-range perturbation performed immediately after release.

[0054] In some embodiments, secondary / multiple mixing can be performed after the "alignment-release-layering-mixing" cycle. For example, short-range perturbations can be added within the avoidance angle to improve reaction uniformity. Furthermore, staged temperature control can be performed. For example, switching the setpoint temperature at different reaction stages. A temperature-maintaining state can also be used after the reaction is complete to facilitate subsequent readout or transfer. In some embodiments, after the reaction is complete, the reaction product can be obtained from the intermediate layer using a puncture method compatible with the soft rubber stopper, or it can be directly fed into the subsequent detection / readout module according to the system design.

[0055] In some embodiments, the apparatus for biochemical reactions according to embodiments of this disclosure can be controlled to perform mixing actions only within avoidance angles that prevent the opening of non-target grooves, and to achieve mutual exclusion between mixing and alignment actions, ensuring that disturbances of the stirring plate do not cause accidental communication between the opening and the unreleased groove. Furthermore, the apparatus can determine the waiting time after reagent release and the mixing trigger sequence based on the process of reagent entering and layering in the intermediate layer. The apparatus can also prioritize temperature control at the alignment interface boundary over isothermal control of other areas of the chamber to ensure a stable temperature field in the core region of the reaction phase.

[0056] according to Figure 4The illustrated embodiment demonstrates how this integrated system effectively addresses the core challenges of small-volume biochemical reactions through a series of innovative designs. First, the system employs an evaporation suppression strategy, consistently sandwiching the reaction phase liquid between the upper and lower protective layers throughout the reaction process. This physically blocks the mass transfer channels for water vapor, significantly reducing volume and concentration drift caused by evaporation. Second, thanks to this sandwich structure, the reaction phase is primarily confined to the intermediate layer and the area adjacent to the interface, greatly reducing direct contact with the container wall and effectively minimizing the non-specific adsorption of trace components. These effects are achieved without the need for additional heated caps or complex sealing mechanisms, making it suitable for micro-scale reaction scenarios.

[0057] In terms of fluid control, the system achieves valveless sequential sample addition. By combining a mechanical structure with "hatching notch positioning" with a fluid design based on "density difference layering," it enables precise release and addition of reagents in multiple steps in a programmable manner. During mixing, the system employs interfacial proximity mixing technology, allowing the stirring plate to reciprocate within a specific avoidance angle. This design ensures efficient mixing while suppressing unintended disturbances to adjacent liquid layers. Furthermore, the system uses a fixed-point temperature control unit to directly implement stable and uniform temperature control at the reaction interface, thereby improving the consistency and repeatability of the entire reaction system.

[0058] Finally, this technical solution possesses excellent parallelism and scalability. Since its core steps do not rely on complex valve and pump fluid networks, it can be easily replicated and expanded under arrayed conditions as described in Example 4, ensuring a high degree of consistency in the operation steps of all parallel units, thus laying the foundation for high-throughput applications. The reuse of multiple units by a single drive and / or a single temperature control further reduces the number of actuators and the complexity of control channels.

[0059] Figure 5A A schematic diagram of the sample addition stage of an example biochemical reaction according to an embodiment of the present disclosure is shown. Figure 5A As shown, during the reaction, a three-phase system is first formed in the reaction chamber 204 of reaction unit 106. The three-phase reaction system consists of three types of immiscible liquids with different densities, which form stable stratification from top to bottom under static or controlled conditions. For example, the first type of liquid 220 (reaction phase) is a liquid with moderate density in the three-phase system, with a density of 0.9–1.1 g / cm³. 3 It is a hydrophilic or water-soluble medium used to hold samples and reagents and as a medium for the reaction (“reaction phase / reaction system”). The second type of liquid 218 is the liquid with the lowest density in the three-phase system, less than that of the first type of liquid. In some embodiments, the density of the second type of liquid 218 may be less than 0.9 g / cm³. 3The density may be lower than the lower limit of the density range of the first type of liquid 220. The second type of liquid 218 is insoluble in water, immiscible with the first type of liquid, and does not react with the first type of liquid 218. The third type of liquid 222 is the densest liquid in the three-phase system, with a density greater than that of the first type of liquid 220 and the second type of liquid 218. In some embodiments, the density of the third type of liquid 222 may be greater than 1.1 g / cm³. 3 The density may be higher than the upper limit of the density range of the first type of liquid 220; the third type of liquid 222 is immiscible with and does not react with the first and second types of liquids. Under a gravitational field, the three types of liquids stably separate into an upper layer of the second type of liquid 218, an intermediate layer of the first type of liquid 220, and a lower layer of the third type of liquid 222. The first type of liquid 220 can exist as a continuous layer in the intermediate layer, or under specific conditions as discrete droplets, located between the second and third types of liquids.

[0060] like Figure 5A As shown, a third-class liquid 222 and a reagent 502 belonging to the first-class liquid are stored in a groove at the bottom 206 of the reaction unit 106. The reagent 502 is sealed in the groove 212 by a groove cover 214 using a sealing ring 308. Because the density of the reagent 502 is less than that of the third-class liquid 222 and it does not mix or react with the third-class liquid, the reagent 502 is isolated from the device by the third-class liquid 222. Misaligned grooves remain sealed to prevent leakage and mismixing.

[0061] Figure 5B A schematic diagram of the sample addition stage of an example biochemical reaction according to an embodiment of the present disclosure is shown. Figure 5B As shown, after the three-phase system is formed in reaction chamber 204, the sample can be added into reaction chamber 204 of reaction unit 106 by piercing the soft rubber stopper with a puncture needle. The sample belongs to the first type of liquid and automatically enters the intermediate layer due to the density difference, fusing with the first type of liquid 220 in reaction chamber 204. After puncture, the soft rubber stopper is reset to restore the seal.

[0062] Figure 5C A schematic diagram of the para- and reagent-releasing stages of an example biochemical reaction according to an embodiment of this disclosure is shown. Figure 5C As shown, after the sample is added, the drive unit rotates the groove cover 214 to align the opening 306 with the target groove 212, thereby releasing the reagent 502. The misaligned groove continues to be sealed by the sealing ring 308 engaging with the lower surface of the groove cover 214.

[0063] Figure 5D A schematic diagram of the release and mixing phase of an example biochemical reaction according to an embodiment of the present disclosure is shown. Figure 5DAs shown, the released reagent 502 belongs to the first type of liquid. After entering the intermediate layer, it merges with the sample in the first type of liquid 220 to form a reaction system. Then, the drive unit drives the stirring plate to reciprocate angularly to agitate the intermediate layer, achieving homogenization of the reaction system. The angular displacement used for homogenization is an avoidance angle, that is, avoiding the position where the notch in the cover coincides with the reagent compartment that has not yet released reagent, to prevent accidental release during homogenization. After homogenization, the groove cover returns to the safe corner area. In addition, the temperature control unit performs point-to-point temperature control at the interface boundary, keeping the reaction phase at a preset temperature to control the biochemical reaction process. After the sequential release, merging, and homogenization of the sample and reagent are completed, the reaction proceeds in the intermediate layer at the preset temperature until the predetermined endpoint conditions are reached (such as the completion of the time / step set in the program).

[0064] According to the embodiments of this disclosure, a three-phase layered reaction platform can be constructed. Without relying on complex microvalve / pumps, it simultaneously achieves evaporation suppression and non-specific adsorption reduction of the reaction phase, sequential automatic release / addition and interface-based homogenization with precise temperature control, as well as high-throughput parallel operation driven by the same mechanism. This reduces system complexity and potential failure points, improves reaction stability, repeatability, and scalability, and lowers manufacturing and maintenance costs.

[0065] Furthermore, the scheme according to the embodiments of this disclosure can achieve evaporation suppression of the reaction phase. By double-sided coating and physical isolation of the intermediate first-type liquid by the upper second-type liquid and the lower third-type liquid, the water vapor mass transfer channel is effectively blocked, significantly suppressing volume and concentration drift under conditions such as cyclic temperature control, thereby improving the stability and endpoint consistency of small-volume reactions. This evaporation suppression strategy can be implemented without a heat-sealing cap.

[0066] Furthermore, the solution according to embodiments of this disclosure can reduce non-specific adsorption caused by direct contact between the reaction phase and the container. The reaction phase is suspended between two immiscible protective liquids, significantly reducing direct contact with the container wall, thereby reducing the risk of non-specific adsorption or inactivation of nucleic acids / proteins, etc., and improving the accurate recovery and reaction effectiveness of trace samples. This also reduces batch-to-batch fluctuations caused by material differences.

[0067] Furthermore, the solution according to the embodiments of this disclosure enables sequential automatic reagent release and "interface-oriented layering" fusion: self-positioning based on density difference and angular positioning of the hatch notch achieves pump-free and valve-free point-to-point, sequential reagent release; the released reagent (first-class liquid) automatically enters the intermediate layer and fuses with the reaction phase, thereby simplifying the actuator, improving sample addition reliability and programmable controllability. Mixing is performed only within the avoidance angle to ensure safe isolation of unordered grooves.

[0068] Furthermore, the solution according to the embodiments of this disclosure can achieve the integration of multi-step processes and simplification of equipment. Within the same reaction unit, key steps such as sample addition, sequential release, interface-near-interface mixing, fixed-point temperature control, and biochemical reaction are integrated using a three-phase stratification + gear / chamber cover mechanism. This reduces the number of pipes / valve / pumps and connection interfaces, thereby reducing system complexity and maintenance costs, and facilitating standardization and mass production.

[0069] Furthermore, the solution according to the embodiments of this disclosure enables high-throughput parallelism and drive multiplexing. Through a single drive of a rack and pinion mechanism and a drive motor—multiple unit linkage—and the coverage of multiple reaction units by a temperature control unit, linear expansion of throughput is achieved without proportionally increasing actuators and control channels; thereby improving throughput while maintaining consistency and reducing expansion costs. The units in the array ensure consistent alignment, release, and mixing actions through positioning protrusions / grooves and angular zero-position unification.

[0070] The various embodiments of this disclosure have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or improvement of the technology in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

[0071] The various embodiments of this disclosure have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical applications, or improvements to the technology in the market, or to enable others skilled in the art to understand the various implementations disclosed herein.

Claims

1. An apparatus (100) for biochemical reactions, comprising: a reaction unit (106), comprising: a reaction cavity (204); a plurality of grooves (212) for accommodating reagents and located in the reaction cavity (204); and at least one groove cover (214) disposed in the reaction cavity (204) and configured to switch between closing and opening at least one groove of the plurality of grooves (212) when driven; and a driving device (110) for driving the at least one groove cover (214).

2. The apparatus according to claim 1, wherein the reaction unit (106) further comprises: a bottom portion (206) comprising a bottom surface abutting the reaction cavity (204), the plurality of grooves (212) being disposed on the bottom surface; a first side wall portion (208) extending from the bottom portion (206) in a vertical direction relative to the bottom surface; and a second side wall portion (210) extending from the first side wall portion (208) in the vertical direction, a first inner diameter of the first side wall portion (208) being greater than a second inner diameter of the second side wall portion (210).

3. The apparatus according to claim 2, wherein the at least one groove cover comprises a single groove cover (214), the groove cover (214) comprising: a main body (314) covering the plurality of grooves (212); and an opening (306) located on the main body (314), wherein the groove cover (214) is configured to misalign the opening (306) with the at least one groove cover (214) when closing the at least one groove cover (214) and align the opening (306) with the at least one groove cover (214) when opening the at least one groove.

4. The apparatus according to claim 3, wherein the bottom portion (206) further comprises a through hole (310), and the groove cover (214) further comprises: a receiving shaft (304) having a first end connected with the main body (314) and a second end extending through the through hole (310); and a first gear (118) connected with the second end of the receiving shaft (304), wherein the driving device (110) is connected with the first gear (118) and configured to drive the first gear (118) to rotate.

5. The apparatus according to claim 4, wherein the driving device (110) comprises: a driving motor (112) comprising an output shaft; a second gear (114) connected with the output shaft; and a gear strip (116) meshing with the first gear (118) and the second gear (114) respectively, wherein the driving device (110) is configured to drive the groove cover (214) to align with a corresponding groove of the plurality of grooves (212) in a preset angle sequence. ​ ​ ​ 6. The apparatus of claim 3, wherein the body (314) further comprises a plurality of stir plates (216) extending from the body (314) in the vertical direction towards the reaction cavities (204), and wherein the drive apparatus (110) is configured to control the body (314) to move back and forth within a predetermined range such that the body (314) encloses unopened grooves (212) among the plurality of grooves (212).

7. The apparatus of claim 6, wherein the body (314) is controlled to perform a circular motion, and the predetermined range is an avoidance angle range within which the body (314) is moved without the opening (306) of the body (314) being aligned with an unopened groove (212).

8. The apparatus of claim 2, further comprising a temperature control unit (104) including a through hole, and the first side wall section (208) is deep into the through hole.

9. The apparatus of claim 8, wherein the second side wall section (210) includes a positioning protrusion cooperating with a recess of the through hole to limit relative movement of the reaction unit and the temperature control unit (104).

10. An apparatus array (10) for biochemical reactions, comprising: a plurality of reaction units, each reaction unit of the plurality of reaction units being configured according to the reaction unit (106) in the apparatus (100) for biochemical reactions according to claims 1 to 9; and a drive unit (110) configured according to the drive apparatus (110) in the apparatus (100) for biochemical reactions and for driving the plurality of reaction units.

11. The apparatus array (10) of claim 10, wherein gear strips (116) of the drive apparatus (110) are respectively engaged with a plurality of first gears of the plurality of reaction units and a second gear (114) of the drive apparatus (110).

12. The apparatus array (10) of claim 11, wherein the drive unit (110) sequentially / synchronously drives respective reaction units of the plurality of reaction units in a round robin or grouped parallel manner to complete site release and mixing.

13. The apparatus array of claim 10, further comprising a plurality of temperature control units, each temperature control unit of the plurality of temperature control units including a through hole, and the plurality of temperature control units are sleeved on the plurality of reaction units via respective through holes.

14. The apparatus array of claim 10, further comprising a temperature control unit including a plurality of through holes, the temperature control unit being sleeved on the plurality of reaction units via the corresponding plurality of through holes.

15. A biochemical reaction method, comprising: adding a first liquid, a second liquid and a third liquid into a reaction chamber (204), respectively, the first liquid being immiscible and non-reactive with the second liquid and the third liquid, the first density of the first liquid being greater than the second density of the second liquid and less than the third density of the third liquid, wherein the first liquid, the second liquid and the third liquid are left to form a stratification of the second liquid, the first liquid and the third liquid from top to bottom; adding a sample into the reaction chamber (204), the sample belonging to the first liquid and mixing with the first liquid in the reaction chamber (204); and adding a plurality of reagents into the reaction chamber (204) in sequence, wherein the plurality of reagents belong to the first liquid and mix with the first liquid in the reaction chamber (204) to perform biochemical reactions.

16. The method of claim 15, wherein the reaction chamber is a reaction chamber (204) of a reaction unit (106) in the device (100) for biochemical reactions according to claims 1 to 9, and the method further comprises: mixing by a plurality of stirring plates (216) in the reaction chamber (204).

17. The method of claim 16, wherein adding the plurality of reagents into the reaction chamber (204) in sequence comprises: driving the at least one recess cover by a driving unit (110) of the device (100) for biochemical reactions such that a plurality of recesses (212) are opened in sequence, thereby releasing reagents in a corresponding recess of the plurality of recesses (212), wherein the released reagents automatically enter the first liquid in the stratification.

18. The method of claim 17, wherein the mixing is performed after each release of the reagents.

19. The method of claim 15, further comprising: performing temperature control operation on the first liquid in the reaction chamber (204) by a temperature control unit of the device (100) for biochemical reactions.

20. The method of claim 15, wherein the first type of liquid is a hydrophilic or water soluble liquid having a density of 0.9 to 1.1 g / cm 3 3.

Images