Wound biological membrane culture system and dynamic in-vitro wound model for antibacterial activity evaluation
By constructing a dynamic ex vivo wound model using isolated porcine skin tissue and a culture medium drip system, the limitations of existing wound models in simulating the wound environment and evaluating the antibacterial effects of dressings were overcome. This enabled accurate evaluation of the performance of antibacterial dressings, reduced costs, and improved experimental reliability.
Patent Information
- Application Number
- CN202520377228.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-05
- Publication Date
- 2026-02-10
- Estimated Expiration
- 2035-03-05
AI Technical Summary
Existing wound models have limitations in simulating the wound environment and evaluating the antibacterial effects of dressings, especially in failing to simultaneously consider airborne bacterial infection and biofilm infection. Furthermore, animal models are costly and have poor reproducibility, while in vitro models fail to simulate the dynamics of real wound tissue structure and nutrient supply.
Using isolated porcine skin tissue as a culture medium, and combining it with a culture medium drip system to simulate the dynamic supply of exudate, a dynamic isolated wound model was constructed. Wound simulation was performed using isolated porcine skin tissue, and the exudate drip system was used to provide continuous nutrition to simulate the clinical wound environment, thereby evaluating the antibacterial wound dressing's anti-plankton and anti-biofilm activity.
It provides a biological matrix that more closely resembles a real wound, can accurately predict the clinical efficacy of antimicrobial dressings, reduces costs, is easy to operate, avoids ethical issues, and can simultaneously simulate acute and chronic wound infections, improving the reproducibility and accuracy of experiments.
Smart Images
Figure CN223892756U_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of medical device biological evaluation technology, specifically relating to a wound biofilm culture system and a dynamic ex vivo wound model for evaluating antibacterial activity. Background Technology
[0002] Wound infection refers to a pathological state in which microorganisms invade, damage, proliferate, and multiply on incomplete skin, delaying or worsening wound healing once they reach a certain level. Based on the duration and severity of the infection, wound infections can be classified as acute or chronic. Acute infections are usually caused by active planktonic bacteria, manifesting as a marked inflammatory response, such as redness, swelling, pain, and fever. Chronic infections are typically associated with biofilm formation, a complex structure composed of an extracellular polymeric matrix secreted by bacteria. Biofilms greatly enhance resistance to host immunity and antibiotics, leading to prolonged wound non-healing. Wound infections not only prolong wound healing time, increase hospital stays and readmission rates, but can even lead to patient death, placing a significant burden on patients' quality of life and the healthcare system.
[0003] Currently, clinical treatment for wound infections primarily involves antibiotic use and local wound care. For acute infections, systemic antibiotic therapy is usually effective, helping the host's immune system control bacterial invasion. However, the overuse of antibiotics has led to an increase in drug-resistant strains. In chronic infections, traditional antibiotic treatments often fail to completely eliminate biofilms, resulting in recurrent wound infections and delayed healing. To address these challenges, antimicrobial wound dressings are increasingly becoming an important tool in wound infection management. Antimicrobial dressings, by releasing antimicrobial agents locally at the wound site, can effectively reduce bacterial load, inhibit biofilm formation, and promote wound healing.
[0004] Currently, an increasing number of novel antibacterial wound dressings are under development or already on the market. The antibacterial activity of these products can include anti-plankton activity and anti-biofilm activity, used for wound infection control at different types or stages. A scientific and rational evaluation of the antibacterial activity of wound dressings will contribute to product development, market launch, and regulation. To more accurately verify the antibacterial efficacy of dressings, it is necessary to construct experimental models that simulate the clinical wound environment. An ideal wound model should be able to simulate real wound conditions, have good reproducibility, be standardized, and be able to predict clinical outcomes well. However, existing wound models have limitations in simulating the wound environment and evaluating the antibacterial effects of dressings. While animal wound infection models can simulate the complex physiological environment of the human body, animal experiments are costly, time-consuming, have poor reproducibility, and involve ethical issues. Research on in vitro wound models can be divided into static and dynamic models based on whether there is a continuous supply of nutrients. Static models have been studied in various types, such as the Lubbock chronic wound biofilm model (LCWB), collagen matrix model, and static cell model (HSE). Although these models incorporate human proteins and cells, they lack complete tissue structure and cannot reflect the distribution of microorganisms and dynamic nutrient supply in skin tissue. Dynamic models, such as the CDC flowreactor and drip flow reactor, are simple to operate, can be standardized for testing, and have a continuous supply of culture medium. However, they are only used to cultivate biofilms, and these biofilms grow on non-biological solid surfaces, which are fundamentally different from biofilms within wound tissue. In addition, some studies have used ex vivo human skin or pig skin to construct ex vivo wound models, but these ex vivo models are basically cultured in well plates, without a continuous supply of culture medium. The defects of the above in vitro / ex vivo models are: (1) using non-biological materials as culture substrates and not considering the influence of wound tissue structure on microorganisms; (2) not considering the continuous exudation dynamics of the wound environment and the gradient distribution of oxygen and nutrients; and (3) not simultaneously considering the two infection states of planktonic bacteria and biofilm infection. Utility Model Content
[0005] The purpose of this invention is to overcome the shortcomings of the above-mentioned models and provide a wound biofilm culture system and a dynamic ex vivo wound model for evaluating antibacterial activity. It is mainly used for the preparation of wound biofilms and the evaluation of the antibacterial activity of antibacterial wound dressings. It uses ex vivo porcine skin tissue to simulate wounds as a culture medium for microorganisms, and combines it with the dynamic supply of simulated exudate. Under the condition of simulating the in vivo environment as much as possible, it realizes the determination of two properties of antibacterial wound dressings: anti-plankton activity and anti-biofilm activity.
[0006] The technical problem to be solved by this utility model is achieved by the following technical solution: a wound biofilm culture system, including a reactor, a glass slide, isolated porcine skin tissue, a waste liquid collection bottle, a bacterial filter and a culture medium drip system;
[0007] The reactor includes an upward-opening test chamber and a detachable sealing cover located at the opening of the test chamber. The test chamber and the sealing cover are sealed together. The test chamber is tilted and has an outlet at the lower end. The sealing cover has a titration head communicating with the test chamber on the higher side and a bacterial filter communicating with the test chamber on the lower side.
[0008] The glass slides and isolated porcine skin tissue are arranged sequentially from bottom to top in the test chamber;
[0009] The outlet is connected to a waste liquid collection bottle, which is equipped with a bacterial filter that communicates with the outside. The dropper is connected to a culture medium drip system and is located above the higher side of the slide.
[0010] The culture medium drip system is used to supply simulated exudate to the reactor.
[0011] In a preferred embodiment of this invention, the culture medium drip system includes an exudate storage bottle and a peristaltic pump. The exudate storage bottle is connected to the peristaltic pump via an exudate delivery pipeline, and the peristaltic pump is connected to the tip head via a pump pipe.
[0012] The exudate storage bottle is equipped with a bacterial filter that connects to the outside environment. A peristaltic pump is used to deliver the simulated exudate from the storage bottle into the reactor, controlling the drip rate while preventing the simulated exudate from coming into contact with the outside environment and becoming contaminated.
[0013] Preferably, this invention also includes a glass dripping bottle, which is installed on the exudate delivery pipeline. The glass dripping bottle is used to observe the flow of the simulated exudate, and it can withstand the pressure steam sterilization process, allowing for high-temperature steam sterilization of the entire model and avoiding the influence of other microorganisms.
[0014] Preferably, the isolated porcine skin tissue of this invention is prepared through wound construction and aseptic treatment. A wound is created on the isolated porcine skin tissue to simulate a human wound, ensuring that the isolated porcine skin tissue used does not carry other bacterial species to avoid affecting the experimental results.
[0015] In a preferred embodiment of this invention, the bottom of the test chamber is provided with an anti-slip protrusion on the side of the liquid outlet. Since the glass slide is a glass product, the friction between it and the bottom of the test chamber is small. The anti-slip protrusion can limit the position of the glass slide, ensuring that the glass slide is located below the titration head and preventing the glass slide from sliding and affecting the test results.
[0016] Preferably, this invention further includes a sealing ring disposed between the sealing cover and the test chamber, wherein the sealing cover and the test chamber are fixedly connected by bolts. The sealing ring seals the gap between the sealing cover and the test chamber, ensuring the airtightness of the test chamber, while the bolts secure the sealing cover and the test chamber, facilitating the insertion and removal of test items.
[0017] Preferably, this invention further includes a first angle adjustment bracket, which comprises a support frame and an angle adjustment plate hinged to the support frame, with the reactor mounted on the angle adjustment plate. This invention utilizes the angle adjustment bracket to adjust the reactor's tilt angle to the desired test angle, and can be used to simulate the effects of different shear forces on bacterial infection. By adjusting the tilt angle of the angle adjustment plate hinged to the support frame, the tilt angle of the reactor can be flexibly adjusted.
[0018] Preferably, this invention also includes a second angle adjustment bracket, which comprises height-adjustable legs positioned below the four corners of the reactor. By adjusting the height of the legs, the tilt angle of the reactor can be adjusted.
[0019] This utility model also discloses a dynamic ex vivo wound model for evaluating antibacterial activity, based on the above-mentioned wound biofilm culture system, including a test dressing and a counterweight.
[0020] The test dressing and counterweight are arranged sequentially from bottom to top above the detached pigskin tissue. The purpose of the counterweight in this invention is to make the dressing fit the pigskin better, simulating the fixing force of bandages or tape on the dressing during use.
[0021] The dynamic ex vivo wound model comprises a culture medium drip system, a reactor, and a waste collection bottle connected in sequence. The bottom of the test chamber of the reactor is tilted. In this invention, a glass slide, ex vivo porcine skin tissue, a test dressing, and a counterweight are arranged sequentially from bottom to top within the test chamber of the reactor. This invention utilizes ex vivo porcine skin tissue for wound construction and microbial inoculation, providing a continuous nutrient supply to simulate airborne bacterial infection or biofilm infection of the wound. This approach more closely approximates actual clinical conditions and more accurately predicts the antibacterial activity of antibacterial wound dressings.
[0022] In a preferred embodiment of this invention, the reactor comprises multiple test chambers arranged side by side, each test chamber being connected to a waste liquid collection bottle and a culture medium drip system. By setting up multiple test chambers, multiple test dressings can be tested simultaneously, allowing for the establishment of multiple parallel sets of antibacterial dressings and control dressings, or for comparison of different types of antibacterial dressing samples.
[0023] Compared with the prior art, the beneficial effects of this utility model are:
[0024] 1. This invention utilizes isolated porcine skin tissue as a culture medium for microorganisms. Porcine skin is very similar to human skin in terms of anatomy and physiology, providing a biological matrix that more closely resembles a real wound surface. A culture medium drip system simulates the dynamic nutrient supply and metabolic waste removal of wound exudate, while simultaneously constructing an oxygen gradient (surface aerobic / deep anaerobic) to better reproduce the heterogeneity and spatiality of microbial growth in the wound. Compared to animal models, this model has the advantages of low cost, ease of operation, and no ethical issues. Compared to existing in vitro / ex vivo models, it avoids static conditions and artificial surface problems, allowing for more accurate prediction of the clinical efficacy of antibacterial wound dressings and contributing to the development of novel dressing products.
[0025] 2. This invention can set different experimental conditions according to the research purpose to simulate the airborne bacterial infection of acute wounds or the biofilm infection of chronic wounds, so as to study the anti-airborne bacterial activity or anti-biofilm activity of antibacterial dressings. Attached Figure Description
[0026] Figure 1 This is a schematic diagram of the wound biofilm culture system of this utility model;
[0027] Figure 2 This is a schematic diagram of the structure of the reactor described in this utility model;
[0028] Figure 3 This is a schematic diagram of the reactor structure in the dynamic ex vivo wound model used for antibacterial activity evaluation in this utility model;
[0029] Figure 4 This is a schematic diagram illustrating the implementation process of preparing the ex vivo porcine skin tissue wound according to this utility model;
[0030] Figure 5 This is a schematic diagram of the structure of the second angle adjustment bracket of this utility model;
[0031] In the diagram, 1 is the reactor, 2 is the glass slide, 3 is the excised pig skin tissue, 4 is the test dressing, 5 is the counterweight, 6 is the waste liquid collection bottle, and 7 is the bacterial filter.
[0032] 101 Test chamber, 102 Sealing cap, 1011 Liquid outlet, 103 Dropper head, 104 Anti-slip protrusion, 105 Sealing ring, 106 Bolt;
[0033] 8. Exudate storage bottle; 9. Peristaltic pump; 100. Exudate delivery pipeline; 200. Pump pipe;
[0034] 10 Glass dripping bottle; 11 First angle adjustment bracket; 111 Support frame; 112 Angle adjustment plate;
[0035] 12. Second angle adjustment bracket. Detailed Implementation
[0036] The technical solutions in the embodiments of this utility model will now be clearly and completely described in conjunction with the accompanying drawings.
[0037] Example 1
[0038] like Figure 1 and Figure 2 As shown, a wound biofilm culture system includes a reactor 1, a glass slide 2, an excised pig skin tissue 3, a waste liquid collection bottle 6, a bacterial filter 7, and a culture medium drip system.
[0039] The reactor 1 includes a test chamber 101 with an upward opening and a detachable sealing cover 102 disposed at the opening of the test chamber 101. The test chamber 101 and the sealing cover 102 are sealed together to ensure the sterility of the test chamber 101. The test chamber 101 is inclined and has an outlet 1011 at the lower end. The sealing cover 102 has a titration head 103 communicating with the test chamber 101 on the higher side and a bacterial filter 7 communicating with the test chamber 101 on the lower side.
[0040] The glass slide 2 and the isolated porcine skin tissue 3 are arranged sequentially from bottom to top in the test chamber 101.
[0041] like Figure 2 As shown, reactor 1 also includes a sealing ring 105 disposed between the sealing cover 102 and the test chamber 101, wherein the sealing cover 102 and the test chamber 101 are fixedly connected by bolts 106. The sealing cover 102 is connected to the reactor 1 body by bolts, and a sealing ring 105 is disposed between the sealing cover 102 and the reactor 1 body for sealing. The sealing ring 105 is an O-ring.
[0042] like Figure 1 As shown, the bottom of the test chamber 101 is provided with an anti-slip protrusion 104 on one side of the liquid outlet 1011. The anti-slip protrusion 104 is provided inside the test chamber 101. The anti-slip protrusion 104 is a protrusion on the bottom surface of the test chamber 101, which is used to block the glass slide 2 and keep the glass slide 2 in a specific position in the test chamber 101. Since the test chamber 101 is tilted when performing biofilm culture or antibacterial activity evaluation experiments, the support can prevent the glass slide 2 from slipping to the bottom of the test chamber 101.
[0043] The outlet 1011 is connected to the waste liquid collection bottle 6, which is equipped with a bacterial filter 7 that communicates with the outside. The titration head 103 is connected to the culture medium drip system and is located above the higher side of the slide 2. The titration head 103 includes a Mininerert valve and a sterile needle inserted into the Mininerert valve. The titration head 103 can also adopt other structures as needed.
[0044] The culture medium drip system is used to supply simulated exudate to reactor 1.
[0045] like Figure 1 As shown, the wound biofilm culture system includes an exudate storage bottle 8 and a peristaltic pump 9. The exudate storage bottle 8 is connected to the peristaltic pump 9 through an exudate delivery pipeline 100, and the peristaltic pump 9 is connected to a tip head 103 through a pump pipe 200.
[0046] The exudate storage bottle 8 is equipped with a bacterial filter 7 that communicates with the outside environment.
[0047] like Figure 1 As shown, the wound biofilm culture system also includes a glass drip bottle 10, which is located between the exudate storage bottle 8 and the peristaltic pump 9. The glass drip bottle 10 is installed on the exudate delivery pipeline 100.
[0048] The ex vivo porcine skin tissue 3 was prepared through wound construction and aseptic processing. The porcine skin was fresh, and wounds were created on the porcine skin to simulate human skin wound infection.
[0049] The exudate storage bottle 8 is equipped with an air inlet, at which a bacterial filter 7 is installed. The waste liquid collection bottle 6 is equipped with an air outlet, at which a bacterial filter 7 is installed. Because the exudate storage bottle 8 will discharge simulated exudate, it must have an air inlet to maintain pressure balance within the bottle. The bacterial filter 7 at the air inlet ensures sterility of the air entering the exudate storage bottle 8. Similarly, because the waste liquid collection bottle 6 will receive waste liquid, it needs an air outlet to maintain pressure balance within the bottle. The bacterial filter 7 at the air outlet ensures sterility of the air exiting the waste liquid bottle. Both the reagent bottle and the bacterial filter 7 can withstand pressure steam sterilization.
[0050] like Figure 1 As shown, the wound biofilm culture system further includes a first angle adjustment bracket 11, which includes a support frame 111 and an angle adjustment plate 112 hinged to the support frame 111. The reactor 1 is mounted on the angle adjustment plate 112.
[0051] In actual experiments, the tilt angle of the bottom of test chamber 101 is generally 10° to ensure that the pigskin and sample do not slip down while the simulated exudate flows down.
[0052] A dynamic ex vivo wound model for evaluating antibacterial activity, based on the aforementioned wound biofilm culture system, includes a test dressing 4 and a counterweight 5.
[0053] like Figure 3 As shown, the test dressing 4 and the counterweight 5 are arranged sequentially from bottom to top above the isolated pig skin tissue 3.
[0054] like Figure 2 As shown, the reactor 1 includes multiple test chambers 101 arranged side by side, each test chamber 101 being connected to a culture medium drip system and a waste liquid collection bottle 6. In this embodiment, the reactor 1, by setting multiple test chambers, can test multiple groups of antibacterial products and control products simultaneously, greatly improving testing efficiency. When multiple test chambers 101 are set, the peristaltic pump 9 enables the channel formed by the multiple test chambers 101 on the reactor 1 to operate simultaneously at a predetermined flow rate.
[0055] The specific implementation method of this model is as follows:
[0056] 1. Wound preparation of excised porcine skin tissue (e.g.) Figure 4 (As shown)
[0057] 1) Fresh pig skin from the same source and the same anatomical location is dehaired and cleaned. Subcutaneous fat and connective tissue are removed with a scalpel, while the epidermis and dermis are preserved to ensure a uniform skin thickness.
[0058] 2) The pigskins were disinfected and sterilized separately, and their integrity and sterility were ensured through histological observation and aseptic examination.
[0059] 3) Cut the pigskin into small pieces of the same size with a scalpel, and use a disposable biopsy puncture machine to create partial skin damage wounds of the same depth in the center of the skin pieces.
[0060] 4) Perform H&E staining on normal and wounded skin tissue to confirm the degree of damage to the skin structure.
[0061] 2. Test for anti-plankton activity
[0062] 1) First, place a sterile glass slide in each test chamber 101 in the reactor, and then place the prepared wounded pig skin, i.e., the ex vivo pig skin tissue 3, on the glass slide 2 with the wound side facing up.
[0063] 2) The prepared bacterial suspension was quantitatively inoculated onto the wound bed in the center of the wounded pig skin, and then the antibacterial dressing or control dressing was placed on the inoculated pig skin.
[0064] 3) Place a sterile counterweight 5 on each dressing sample to ensure good contact between the dressing and the pigskin during the test. After installing the sealing cap 102, adjust the reactor 1 to a certain angle with the horizontal plane.
[0065] 4) Turn on the peristaltic pump 9 and set the desired flow rate so that the simulated exudate slowly drips onto the glass slides 2 in each test chamber 101, is absorbed by the bottom of the pig skin, continuously supplies nutrients to the microorganisms on the wound surface, and then flows out from the outlet 1011 of the reactor 1.
[0066] 5) After a certain period of application, the dressing and pigskin are removed together. The survival rate and morphology of microorganisms in the pigskin tissue are observed using fluorescence staining and laser scanning confocal microscopy (CLSM). Simultaneously, microorganisms in the tissue are recovered by ultrasound and vortexing, and after gradient dilution, microbial counting is performed. Qualitative and quantitative data on the anti-planktonic activity of the test dressing can then be obtained.
[0067] 3. Tests for anti-biofilm activity
[0068] 1) First, place a sterile glass slide in reactor 1, then place the prepared wounded pigskin on top of the glass slide with the wound side facing up.
[0069] 2) The prepared bacterial suspension was quantitatively inoculated onto the wound bed in the center of the wounded pig skin. The peristaltic pump 9 was turned on and the flow rate was set. After different incubation times (such as 24h, 48, 72h, etc.), the pig skin tissue was collected. The tissue was repeatedly washed with sterile PBS to remove surface airborne bacteria. The bacterial quantity, coverage, thickness, and three-dimensional distribution of the biofilm were examined by fluorescent staining, CLSM observation, and viable cell counting to determine the incubation time of the mature biofilm.
[0070] 3) Select the time point when a mature biofilm is formed, place the antibacterial dressing or control dressing on the pig skin, place a counterweight on the dressing, and continue drip culture.
[0071] 4) After a certain period of time, the dressing and pigskin are removed together. The biofilm on the pigskin tissue is subjected to fluorescent staining and CLSM observation. At the same time, microorganisms in the tissue are recovered by ultrasound and vortex oscillation, and microbial counting is performed after gradient dilution. Qualitative and quantitative data on the anti-biofilm activity of the test dressing can then be obtained.
[0072] Example 2
[0073] like Figure 5 As shown, unlike Example 1, the wound biofilm culture system further includes a second angle adjustment bracket 12. The second angle adjustment bracket 12 includes height-adjustable legs, which are positioned below the four corners of the reactor 1. Specifically, the legs are lifting screws.
Claims
1. A wound biofilm culture system, characterized in that: Includes a reactor (1), a glass slide (2), an excised pig skin tissue (3), a waste liquid collection bottle (6), a bacterial filter (7), and a culture medium drip system; The reactor (1) includes a test chamber (101) with an upward opening and a detachable sealing cover (102) provided at the opening of the test chamber (101). The test chamber (101) and the sealing cover (102) are sealed together. The test chamber (101) is inclined. A liquid outlet (1011) is provided at the lower end of the test chamber (101). A titration head (103) communicating with the test chamber (101) is provided on the higher side of the test chamber (101) of the sealing cover (102). A bacterial filter (7) communicating with the test chamber (101) is provided on the lower side of the test chamber (102). The glass slide (2) and the isolated porcine skin tissue (3) are arranged sequentially from bottom to top in the test chamber (101); The outlet (1011) is connected to the waste liquid collection bottle (6), the waste liquid collection bottle (6) is equipped with a bacterial filter (7) that communicates with the outside, and the dropper (103) is connected to the culture medium drip system and is located above the higher side of the slide (2). The culture medium drip system is used to supply simulated exudate to the reactor (1).
2. The wound biofilm culture system according to claim 1, characterized in that: The culture medium drip system includes an exudate storage bottle (8) and a peristaltic pump (9). The exudate storage bottle (8) is connected to the inlet of the peristaltic pump (9) through an exudate delivery pipeline (100), and the outlet of the peristaltic pump (9) is connected to the titling head (103) through a pump pipe (200). The exudate storage bottle (8) is equipped with a bacterial filter (7) that is connected to the outside.
3. The wound biofilm culture system according to claim 2, characterized in that: It also includes a glass dropper bottle (10), which is disposed on the exudate delivery pipeline (100).
4. The wound biofilm culture system according to claim 1, characterized in that: The isolated porcine skin tissue (3) was prepared by wound construction and aseptic treatment.
5. The wound biofilm culture system according to claim 1, characterized in that: The bottom of the test chamber (101) is provided with anti-slip protrusions (104) on one side of the liquid outlet (1011).
6. The wound biofilm culture system according to claim 1, characterized in that: The reactor (1) also includes a sealing ring (105) disposed between the sealing cover (102) and the test chamber (101), the sealing cover (102) and the test chamber (101) being fixedly connected by bolts (106).
7. The wound biofilm culture system according to claim 1, characterized in that: It also includes a first angle adjustment bracket (11), which includes a support frame (111) and an angle adjustment plate (112) hinged to the support frame (111), and the reactor (1) is disposed on the angle adjustment plate (112).
8. The wound biofilm culture system according to claim 1, characterized in that: It also includes a second angle adjustment bracket (12), which includes height-adjustable legs positioned below the four corners of the reactor (1).
9. A dynamic ex vivo wound model for evaluating antibacterial activity, based on the wound biofilm culture system according to any one of claims 1-8, characterized in that: Includes test dressing (4) and counterweight (5); The test dressing (4) and the counterweight (5) are arranged from bottom to top above the isolated pig skin tissue (3).
10. The dynamic ex vivo wound model for evaluating antibacterial activity according to claim 9, characterized in that: The reactor (1) includes multiple test chambers (101) arranged side by side, each test chamber (101) being connected to a culture medium drip system and a waste liquid collection bottle (6).