Akura PLUS Hanging Drop System, previously GravityPLUS
a photo of the Akura PLUS Hanging Drop System
an infographic of a spheroid transfer using the Akura PLUS Hanging Drop System
Akura PLUS Hanging Drop System with SureDrop
a comparison of Insphero culture well plates

Akura™ PLUS Hanging Drop System (10/pack)

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Overview of Akura™ PLUS Hanging Drop System

Automation compatible  – Secure handling – No surface attachment 

Previously GravityPLUS Hanging Drop System.

The world-famous and unique Akura™ PLUS Hanging Drop System in a 96-well format with automation-compatible top-loading.

  • Loading of cell suspension from the top through unique SureDrop™ inlet engineered for highly uniform and stable hanging drops
  • Gravity-assisted formation of uniform spheroid/organoid morphology and functionality in long-term culture results in one spheroid per well
  • Suitable for many cell types, including cells that don't normally form spheroids or organoids on ultra-low attachment surfaces


Cat.-No.: CS-PF24

    Features of Akura™ PLUS Hanging Drop System

    The Hanging Drop System contains 10 Akura™ PLUS Hanging Drop Plates and 10 Akura™ 96 Spheroid Plates, individually wrapped, made of polystyrene and cyclo olefin polymer, sterile, and includes a lid.  


    • ANSI/SLAS 96-well standard format for full compatibility with automated liquid handling systems
    • SureDrop™ inlet technology enables the gravity-assisted formation of uniform spheroids in scaffold-free conditions, resulting in one spheroid/organoid per well
    • The Akura™ PLUS Spheroid Hanging Drop System consists of a two-plate system: one Akura™ PLUS Hanging Drop Plate and one Akura™ 96 Spheroid Microplate



    • Top-loading replaces manual drop dispensing and upside-down flipping of plates with automated multichannel pipetting
    • Free-floating spheroids are fully accessible and can be transferred to Akura™ 96 Spheroid Plates for long-term culturing or analysis


        At InSphero we are using our Akura™ PLUS Microplates daily to produce 3D microtissues for our partners in pharma and biotech. Our manuals and protocols contain valuable information and hands-on advice to make sure that these great plates work in your hands perfectly.

        A detailed protocol for the production and transfer of spheroids in the Akura™ PLUS Hanging Drop System is provided in the product manual.


        FAQs of Akura™ PLUS Hanging Drop System

        Q: Is the GravityPLUS Hanging Drop System identical to the Akura™ PLUS Spheroid Hanging Drop System?

        A: Yes, both systems are identical. We only changed the name as we recently expanded the InSphero microplate portfolio with additional products (e.g. Akura™ 384 Spheroid Microplate) and therefore, decided to put all plates under the new family brand name AkuraTM.

        Q: Could you recommend a cell concentration for my cell suspension for the generating of spheroids? 

        A: For long-term growth profiling, we recommend starting with low cell numbers (250 – 500 cells per drop of 40 µl). If the use of non-proliferating cells or rapid production of larger spheroids is required, start with higher numbers (from 2500+ cells per 40 µl). 

        Generally, we recommend trying different concentrations for defining your optimal range when using new cell types. 

        Q: What is the SureDrop™ inlet? 

        A: InSphero’s Akura™ PLUS Hanging Drop Plate features the patent-pending SureDrop™ microtechnology, which allows for precise dispensing into and aspirating from hanging drops. As the drop volume corresponds to the seeding cell number, spheroids produced in Akura™ PLUS Hanging Drop Plates display outstanding size consistency, with variation in diameter of 5% and less across an entire 96-well plate.

        To assure the SureDrop™ seal, it is important that the pipette tips make sufficient contact with the well surface to assure complete liquid transfer and uniform drop formation. The spring-loaded wells' elasticity adjusts to ensure contact is maintained when downward pressure is applied during pipetting.  

        Q: What is the optimal volume per drop in the Akura™ PLUS Hanging Drop Plate? 

        A: To achieve an optimal and stable hanging drop, gently deliver 40 µl (pipetting speed < 50 µl/sec) of cell suspension into each well of the Akura™ PLUS Hanging Drop Plate. Important: To generate spheroids that are uniform in size and cell composition it is essential to assure a homogeneous distribution of the cells by gently pipetting up and down prior to seeding into the Akura™ PLUS Hanging Drop Plate. 

        Q: Why do you recommend pre-wetting Akura™ 96 Plate wells prior to spheroids transfer? 

        A: Pre-wetting the wells of the Akura™ 96 Plate is required prior to transfer to prevent the inclusion of air bubbles. For that, apply 40 µl of aggregation medium to each well by placing the tips far into the wells. Remove the pre-wetting solution by placing the tip at the ledge of the upper cavity of the well. Aspirate medium until is completely removed from each well. A negligible amount (< 5-7 µl) may remain in the bottom of the chamber. 

        Q: How do you transfer spheroids into the receiver (Akura™ 96) Plate? 

        A: Place the frame with stripes of the Akura™ PLUS Plate onto the Akura™ 96 Plate by positioning the three pins into the corresponding holes on the top surface of the Akura™ 96 Plate. The drops under the Akura™ PLUS Plate will then be perfectly aligned with the wells of the Akura™ 96 Plate underneath.

        Using a slow pipetting speed (≤ 10 µl /sec), add 70 µl of medium or buffer through the inlet of the Akura™ PLUS Hanging Drop Plate wells. Make sure that the pipette tip forms tight contact with the well inlets. 

        Q: What is the best way to prevent evaporation in the outer wells of my plates? 

        A: Evaporation in the outer (perimeter) rows of wells is a phenomenon common to most low-volume culture platforms, and thus requires careful attention to maintain proper humidity control. Evaporation in the outer rows of hanging drops (Akura™ PLUS Plate) or wells of the Akura™ 96 Plate although infrequent when following the recommendations below, is a possibility.

        If not controlled, pronounced evaporation can result in the concentration or precipitation of media components (e.g. serum, salt) that can impact spheroid formation or health, and can alter the effective concentration of a compound/additive in the medium over the course of a long-term experiment.

        To provide maximum humidity control when using the Akura™ PLUS Hanging Drop System, we recommend the following: 

        • Use an incubator with good humidity control (>95% of rel. humidity), and exercise best practices in maintaining and minimizing loss of humidity (e.g. minimize incubator door opening and closing).
        • During microtissue formation in the Akura™ PLUS Hanging Drop Plate, always use the supplied humidifier pad in the base plate, thoroughly soaking it with sterile 0.5x diluted PBS. This is key to maintaining proper humidity in the Akura™ PLUS Plate during microtissue maturation in the hanging drop.
        • For incubators with poor humidity control, hypotonic buffer solutions (e.g. 0.2× PBS) may be applied to the humidifier pad.
        • For culture in the Akura™ 96 Plate, at least 50-70 µl of the medium in each well is recommended and can be increased to a maximum of 80 µl if incubator humidity control is a persistent issue. Medium exchange frequency can also be increased to every other day or daily if conditions dictate. 
        • We recommend the use of the InSphero Incubox to reduce edge effects when performing long-term studies with low-frequency medium exchanges.

        Selected Publications

        Disclaimer - InSphero Akura™ PLUS Spheroid Hanging Drop System was previously known as the InSphero GravityPLUS™ plate.

        Disclaimer -  InSphero’s plate technology is now under the name Akura™.