FireGene Cochlea Dissociation Kit - Inner Ear Cell Prep

Overview

FireGene Cochlea Dissociation Kit is a specialized enzymatic solution optimized to isolate single cells from delicate cochlear tissue. Designed for use in single-cell sequencing and auditory research, this kit ensures high-viability cell suspensions for advanced studies in hearing loss, balance disorders, and neurobiology.

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Background Information

• Driven by Clinical and Scientific Research Needs:

  • Understanding inner ear biology and hearing mechanisms requires accurate dissociation of cochlear tissue into single cells.
  • Traditional methods often fail to isolate hair cells and auditory neurons without damage.
  • The kit supports:
    • Research on age-related hearing loss, Ménière’s disease, and genetic hearing impairments.
    • Identification of gene expression profiles linked to hair cell degeneration and regeneration.
    • Development of targeted therapies for restoring hearing and treating balance dysfunction.

• Background of Technological Development:

  • Mechanical or chemical dissociation methods often compromise cell integrity and yield.
  • This kit employs:
    • A precise enzymatic digestion strategy that matches the biochemical makeup of cochlear ECM.
    • Carefully tuned enzyme types, concentrations, and reaction times.
    • A robust protocol to achieve efficient, reproducible cell release with excellent viability.

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Detection Principle

• Based on a synergistic enzymatic digestion process tailored to the cochlea:
  • Cochlear tissue is finely sectioned for maximal enzyme exposure.
  • Reagents are added in sequence under controlled temperature and timing.
  • The enzymes act to degrade ECM components and loosen intercellular adhesions.
• Final Output:
  • A clean, viable single-cell suspension ideal for scRNA-seq, auditory cell profiling, and regenerative studies.
    

Specifications

Applications	Single-cell sequencing, cell culture or other cell-related detections
Compatible Sample Types	Cochlea tissue
Supported Instruments	Water bath, horizontal centrifuge, cell counter
Storage	-20 °C
Shelf-life	24 months

Kit Components

10 Reactions

Component	10 Reactions/Kit
Cochlea DS (Cochlea Dissociation Solution)	2 × 1.25 mL

50 Reactions

Component	50 Reactions/Kit
Cochlea DS (Cochlea Dissociation Solution)	10 × 1.25 mL

 

Product FAQ

1.    Q: Is this kit only suitable for fresh cochlear tissue? Is it effective for cryopreserved and resuscitated cochlear tissue?

A: The kit is mainly suitable for fresh mammalian cochlear tissue (e.g., cochlear tissue from mice, rats, and humans). It should be used with caution for cryopreserved and resuscitated cochlear tissue: Sensitive cells in the cochlea (such as hair cells and supporting cells) are prone to rupture due to ice crystal damage during cryopreservation. After resuscitation, the viability of dissociated cells will be 25%-35% lower than that of fresh tissue. Pre-quality inspection via trypan blue staining is required (viability ≥55% to be usable).

2.    Q: The instruction manual requires cutting 200mg of fresh cochlear tissue. Will insufficient tissue quantity (e.g., 80mg) or excessive tissue quantity (e.g., 250mg) affect the dissociation effect? How to adjust the operation?

A: Yes, it will affect the effect. ① Insufficient tissue quantity (<150mg): The content of target cells (e.g., hair cells) in cochlear tissue is inherently low. Insufficient quantity will result in an extremely low final single-cell yield (less than 40% of the normal amount), and the cell pellet will be unobvious during subsequent centrifugation and stratification, easily leading to collection omission. It is recommended to combine multiple 80mg cochlear tissue samples (to a total weight of 180-200mg) and add the dissociation solution according to the conventional dosage to ensure the total number of target cells meets experimental requirements. ② Excessive tissue quantity (>220mg): The space in a 5mL centrifuge tube is limited, so the tissue cannot be fully minced and dispersed. The enzymolysis solution cannot act evenly on all cells, leading to incomplete dissociation of local tissue and over-digestion of local cells. The tissue should be split into two tubes for processing, with each tube containing 180-200mg of tissue and corresponding to 240μL of dissociation solution + 2760μL of RPMI 1640 medium, to avoid the impact of tissue crowding on enzymolysis efficiency.

3.    Q: Cochlear tissue contains sensitive cells such as hair cells, and the digestion time in Step 3 is 0.5-2 hours. How to determine the optimal digestion time? What impact will improper digestion time have on sensitive cells?

A: The optimal digestion time needs to be dynamically determined through "microscopic quality inspection", and observation is recommended every 15 minutes: ① When more than 80% of the cells in the field of view are in a single dispersed state, there are no obvious clusters of more than 5 cells, and trypan blue staining shows viability ≥70%, terminate digestion immediately. ② If hair cells (columnar in shape with obvious cilia) are observed to start swelling or rupturing, digestion must be terminated even if the minimum digestion time (0.5 hours) has not been reached. Insufficient digestion time: There are many tissue debris, and target cells such as hair cells are still wrapped in the tissue, resulting in a low single-cell yield. Excessive digestion time: Sensitive cells (such as hair cells and spiral ganglion cells) will have their cell membranes ruptured due to over-enzymolysis, leading to a sharp drop in viability. The proportion of target cells in subsequent experiments (e.g., single-cell sequencing) will be less than 30%, which cannot meet research needs.

4.    Q: Steps 5 and 6 require filtration with a 70μm cell sieve and rinsing the centrifuge tube 3 times. What impact will omitting one rinsing step or replacing with a 50μm/100μm sieve have on the cochlear cell suspension?

A: Omitting one rinsing step will cause approximately 1/3 of the target cochlear cells (e.g., hair cells, supporting cells) to remain on the inner wall of the centrifuge tube, reducing the final yield by more than 30%. Cochlear cells are inherently small in quantity and easily adsorbed on the tube wall, so 3 rinsing steps are crucial to ensure full cell recovery. A 50μm or 100μm sieve cannot be used as a replacement: ① The 50μm sieve has too small a pore size. Although it can filter tissue debris, it will retain some smaller cochlear cells (e.g., spiral ganglion cells, with a diameter of approximately 8-12μm), leading to the loss of target cells. ② The 100μm sieve has too large a pore size and cannot effectively filter undigested cochlear tissue debris (e.g., basement membrane debris). These debris will enter subsequent steps along with the cells, interfering with the accuracy of cell counting and potentially clogging the microchannels of the single-cell sequencing chip, affecting the experimental process.

5.    Q: The instruction manual mentions that "DMEM medium can replace RPMI 1640 medium". After replacement, is it necessary to adjust centrifugation parameters or digestion time? Is there any difference in the impact of the two media on the viability of sensitive cochlear cells (e.g., hair cells)?

A: There is no need to adjust centrifugation parameters (still 4℃, 300×g for 5 minutes) or digestion time after replacement. Both DMEM and RPMI 1640 are common basal media for mammalian cells. Although they differ in glucose and amino acid content, both can provide a suitable osmotic pressure (280-320mOsm/kg) and pH (7.2-7.4) for cochlear tissue dissociation, with no impact on enzymolysis efficiency. The impact on the viability of sensitive cochlear cells is minimal: Experimental data shows that after dissociating mouse cochlear tissue with the two media, the difference in hair cell viability is ≤6%, and the difference in the viability of supporting cells and nerve cells is ≤5%. The medium can be selected based on the existing inventory in the laboratory. If cochlear cell culture is required in subsequent steps, it is recommended to prioritize the medium consistent with the culture system to reduce the stress response of cells due to environmental changes.

6.    Q: The cochlear tissue dissociation solution needs to be stored at -20℃. If the ice pack melts during transportation and the reagent is left at 4℃ for 2 hours, can it still be used? What impact does repeated freezing and thawing have on the enzyme activity in the dissociation solution?

A: The reagent can still be used after being left at 4℃ for 2 hours, but it must be immediately returned to -20℃ and fully mixed before use. The enzymes (e.g., collagenase, hyaluronidase) in the dissociation solution lose ≤10% of their activity when stored at 4℃ for a short period (≤2 hours), and can still effectively destroy the extracellular matrix of cochlear tissue without affecting the dissociation effect. Repeated freezing and thawing will lead to a significant decrease in enzyme activity: Each freeze-thaw cycle reduces enzyme activity by 12%-15%; after more than 3 freeze-thaw cycles, the activity is less than 50%, which cannot fully decompose the fiber components in cochlear tissue. After dissociation, there will still be a large amount of tissue debris, and the release of target cells (e.g., hair cells) will decrease by more than 60%, which cannot meet experimental needs. It is recommended that after receiving the kit, aliquot the 2×1.25mL dissociation solution into 250μL/tube (each tube corresponds to one experimental dose), seal it, store at -20℃, and take one tube for each experiment to avoid repeated freezing and thawing.

7.    Q: The centrifugation parameters for Steps 8 and 9 are "4℃, 300×g for 5 minutes". If only a vertical centrifuge is available in the laboratory or the centrifugation speed is incorrect (e.g., 200×g, 400×g), what impact will this have on cochlear cells? Can room-temperature centrifugation replace 4℃ centrifugation?

A: A vertical centrifuge cannot replace a horizontal centrifuge. The direction of centrifugal force of a vertical centrifuge is perpendicular to the centrifuge tube, which will cause uneven precipitation of cochlear cells, easily resulting in loose precipitation or adhesion to the tube wall. Sensitive cells (e.g., hair cells) are prone to being sucked away when discarding the supernatant; a horizontal centrifuge allows cells to precipitate evenly at the bottom of the tube, facilitating accurate collection. Impacts of incorrect parameters: ① Speed of 200×g: Insufficient centrifugal force causes cochlear cells (especially hair cells) to fail to precipitate fully and be lost with the supernatant, reducing the yield by more than 45%. ② Speed of 400×g: Excessive centrifugal force squeezes fragile hair cells and nerve cells, leading to cell membrane rupture and a 30%-35% decrease in viability. Room-temperature centrifugation cannot replace 4℃ centrifugation. Room temperature accelerates the metabolism of cochlear cells, and the residual enzymolysis solution has enhanced activity at room temperature, further damaging sensitive cells. Centrifugation at 4℃ can maintain a low metabolic state of cells, reduce viability loss, and ensure the quality of target cells.

8.    Q: After quality control, it is required to "carry out subsequent experiments immediately". If subsequent experiments cannot be conducted immediately, can the prepared cochlear single-cell suspension be stored for a short period? What are the strict restrictions on storage conditions and time?

A: Short-term storage is possible, but the conditions are extremely strict: It must be stored in a sealed container at 4℃ in the dark for no more than 30 minutes, and repeated shaking or vibration must be avoided throughout the process. During storage, adjust the cell concentration to 1×10⁶-1×10⁷ cells/mL using PBS containing 5% FBS, and place it in a low-adhesion centrifuge tube to prevent cell adhesion or damage from mechanical force. After 30 minutes, the viability of sensitive cochlear cells (e.g., hair cells) will decrease rapidly (15%-20% every 30 minutes), and cell aggregation is prone to occur; if stored for more than 1 hour, the viability of hair cells may be lower than 50%, making it unsuitable for high-precision experiments such as single-cell sequencing and cell function detection. Before use, re-conduct trypan blue staining quality inspection; only cells with viability ≥65% and single-cell ratio ≥80% can be used. At the same time, gently pipette 3-5 times (avoid violent pipetting to damage hair cell cilia) to disperse slightly aggregated cells.

9.    Q: Compared with the multi tissue dissociation kit of this brand (FG-BA3303), what are the core advantages of this cochlear-specific kit? Can FG-BA3303 be used as a replacement for this product to dissociate cochlear tissue?

A: The core advantages lie in the "optimization of the enzymolysis system for the characteristics of cochlear tissue": ① Lower enzyme concentration (the enzyme concentration of FG-BA3321 dissociation solution is only 60% of that of FG-BA3303), avoiding over-digestion and damage to sensitive cells. ② Addition of hair cell protective components (e.g., low-concentration antioxidants) can reduce oxidative stress damage to hair cells during dissociation, and the hair cell recovery rate is more than 40% higher than that of FG-BA3303. ③ Better adaptability to enzymolysis time, which can balance tissue dissociation efficiency and cell viability without significant adjustments. FG-BA3303 cannot be used as a replacement. FG-BA3303 is a general-purpose kit, and its enzyme concentration and components are designed for ordinary tissues. When used for cochlear tissue, it is prone to massive death of hair cells and spiral ganglion cells, with viability less than 30%, and incomplete tissue dissociation, making it impossible to obtain a single-cell suspension that meets experimental needs. The cochlear-specific FG-BA3321 kit must be used.