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OkaGel FAQ
OkaGel is a sterile Gelatin Methacryloyl (GelMA) hydrogel product. We offer OkaGel in both ready-to-use liquid form and powder form. Both forms are suitable for long-term storage. OkaGel has a high degree of cell viability and a relatively low rate of degradation compared to other commercial GelMA products. It arrives at your door ready to use for all your research and 3D bioprinting needs.
OkaGel is compatible with a variety of photoinitiators. We recommend using the complimentary Irgacure photoinitiator that comes with every purchase of OkaGel. Make sure to fully dissolve the photoinitiator with the liquid GelMA before attempting to crosslink. Once the Irgacure is fully dissolved take care not to allow unwanted light exposure to the OkaGel. To retain cell viability, exposure times of <3 minutes with UV light wavelengths above 400 nm should be used.
OkaGel is temperature sensitive and forms a solid gel at room temperature (approximately 22℃). At temperatures above 37℃ the viscosity of OkaGel is much lower and the material acts as a liquid. The gelation and viscosity of uncrosslinked OkaGel may be freely manipulated within the temperature range of 1℃ to 60℃.
We recommend OkaGel be stored in an opaque waterproof container. OkaGel solid should be stored in a cool, dry, and dark place. Please note that it is recommended that after the product is prepared with the accompanying photo crosslinker it should be used within 24 hours to ensure completely reproducible physical characteristics.
Our new and innovative method for manufacturing GelMA allows us to produce sterile batches. Each step is conducted in a controlled environment and all reagents are either chemically sterilized or autoclaved. Every single batch of our OkaGel products is tested to ensure sterility.
Our new and innovative method for manufacturing GelMA allows us to produce sterile batches. Each step is conducted in a controlled environment and all reagents are either chemically sterilized or autoclaved. Every single batch of our OkaGel products is tested to ensure sterility.
OkaGel exhibits the capacity to promote the growth of a wide variety of cells at differing concentrations. Our tests show indications of cell viability from as little as 2.5% to concentrations close to 20%. When photocrosslinking Okagel we recommend concentrations of around 5% to generate stable cell scaffolding.
OkaGel exhibits the capacity to promote the growth of a wide variety of cells at differing concentrations. Our tests show indications of cell viability from as little as 2.5% to concentrations close to 20%. When photocrosslinking OkaGel we recommend concentrations of around 5% to generate stable cell scaffolding.
OkaGel has a bloom of 300, and a degree of methacrylation of 80%.
OkaGel Solid
- The stability of our solid form of OkaGel is ideal for long-term storage when kept under recommended conditions.
- OkaGel solids are perfect for bulk storage. They take up far less valuable shelf space in cold chemical storage than OkaGel liquid.
- OkaGel solids allow you to use the aqueous solvent of your choice when preparing your hydrogel.
OkaGel Liquid
- Liquid OkaGel products come ready to use at the requested concentration.
- Solid GelMA can take upwards of 2 days to fully dissolve! Use the prepared liquid Okagel to save valuable time and money.
- By having pre-prepared liquid Okagel you can be certain that your batch of GelMA is sterile and consistent with previous batches.
- All OkaGel Liquids are prepared in a sterile phosphate buffer solution, you can be confident your hydrogel will retain a stable pH.
- Liquid OkaGel will be sent via cold shipping to ensure quality is maintained as you receive it.
- OkaGel liquid is ideal for time-sensitive research, and it retains a high degree of quality within 5 days of receipt.
When you are preparing OkaGel with a photoinitiator, it is important to ensure that all the components are thoroughly mixed. For example, our OkaGel solid comes with EosinY, Triethanolamine, and Vinyl-2-pyrrolidinone. Carefully mix OkaGel with the components by gently pushing them back and forth until the red colour from EosinY (red acid dye) is fully blended in.
If you’d like to discuss your concerns in detail, please schedule a meeting with a GelMA specialist here.
Okamatrix FAQ
OkaMatrix is a basement membrane compound derived from Engelbreth-Holm-Swarm (EHS) mouse sarcoma cells. This cell line is particularly rich in extracellular matrix proteins, making it an excellent tool for biological research. The main components of OkaMatrix are laminin, collagen IV and entactin. Together, these proteins work to form organized structures which provide the physical stimulation that is essential for proper cell growth. OkaMatrix also contains the following naturally occurring growth factors found in EHS aggregates: insulin-like growth factor, TGF-b, epidermal growth factor, platelet-derived growth factor, fibroblast growth factor, and vascular endothelial growth factor.
On average, the protein concentration of OkaMatrix is 8-26 mg/mL depending on the particular product number. The protein specific concentration can be found on the unit’s label.
OkaMatrix is produced in EHS tumors in mice. The ECM is extracted, purified using dialysis and then washed. The resulting OkaMatrix is a basement membrane material that is especially rich in ECM protein components to promote cell growth.
OkaMatrix can be used in a variety of biological applications. It can be used to: coat the bottom of cell culture plates to improve cell attachment, promote cell growth and proliferation in 2D cell culture, provide essential mechanical cues for 3D cell culture, stimulate organoid formation and can be implanted in vivo for localized delivery of various compounds.
Yes, OkaMatrix is temperature sensitive. As it is a biological material, it must be kept frozen in order to stay fresh when not in use. It acts as a liquid at low temperatures and gels at higher temperatures.
NOTE: OkaMatrix is non-thermoreversible. Once OkaMatrix reaches 37°C, it becomes irreversibly gelled and can no longer be liquified.
OkaMatrix is a naturally occurring basement membrane complex produced by the EHS cell line. The natural origin of OkaMatrix means the proteins present are biologically active at body temperature, 37°C. Between 22°C and 37°C, laminin, collagen IV and entactin have enough energy to bind to each other and organize their native structure, forming a gel. At 4°C, the activation energy of these proteins is too low and they cannot form their organizational bonds to gel, thus leaving them in a liquid state.
OkaMatrix is a biological compound and needs to be stored accordingly. For short term storage in cases where OkaMatrix is used to precoat plates, OkaMatrix can be refrigerated at 4°C for up to a week, however it is not recommended to store OkaMatrix at 4°C for longer periods. For regular storage, OkaMatrix should be kept at -20°C to avoid freeze-thaw cycles.
Yes, OkaMatrix can be stored at -80°C, however it must be aliquoted into tubes compatible with ultracold temperatures, such as polypropylene. The glass container OkaMatrix arrives in is not compatible with ultracold temperatures.
OkaMatrix should be placed on ice and left in a 4°C refrigerator overnight.
It is not recommended for OkaMatrix to undergo freeze-thaw cycles. Exposing OkaMatrix to multiple cycles can lead to OkaMatrix becoming clumpy, therefore it is recommended that freeze-thaw cycles of OkaMatrix are limited. Aliquot OkaMatrix once it is received and store it at -20°C. Aliquots can be used as needed while the remaining compound is kept frozen.
Yes, it is essential to chill all of your equipment before and during OkaMatrix handling. OkaMatrix will begin to gel above 10°C, therefore using cool pipette tips and tubes will help to maintain OkaMatrix fluidity and ease of handling.
Yes, OkaMatrix can be diluted using cell culture media to reduce the protein concentration for various applications. Diluting OkaMatrix to achieve a lower protein concentration will reduce its viscosity when liquid, but it will not gel as effectively at higher temperatures. Be sure to check the protein concentration of your specific lot number before diluting; it can be found on the vial label. Only dilute OkaMatrix to specific concentrations (mg/mL). For in vivo applications, do not dilute OkaMatrix below 4mg/mL as it will not gel completely.
Mix additives into OkaMatrix by gently pipetting the mixture up and down many times. Do not shake or vortex OkaMatrix as this will introduce bubbles which are difficult to remove.
A thin layer (~50um) of OkaMatrix should be used when a protein coat is desired for cell attachment or proliferation assays. A thin layer of OkaMatrix can be deposited on the bottom of a plate or dish prior to seeding with cells.
A single thick layer (150-200um) of OkaMatrix should be used to generously coat the bottom of a plate or dish for cell invasion assays or for basic 3D culture applications. Here, a single thick layer deposited before seeding with cells can provide a basement membrane for cells to interact with, invade and proliferate in 3 dimensions.
When complex cell interactions are required, such as mechanical cues required for directed differentiation, 3D culture methods can be used. OkaMatrix can be used in various 3D cell culture methods, which can be found here.
General cell culture
Standard OkaMatrix:
Without Phenol Red: useful for assays that involve colour detection
Reduced Growth Factor: useful for cell lines which are more sensitive
Reduced Growth Factor Without Phenol Red: for sensitive cell lines and use of colour detection
Stem cell culture:
Human embryonic stem cell-verified OkaMatrix:
Without Phenol Red: can also be used for human induced pluripotent stem cell (hiPSC) culture.
In vivo
Concentrated OkaMatrix:
With Phenol Red: can be used for in vivo implantation and plug assays
Without Phenol Red: useful if UV light exposure or photoinitiators are used
Growth factor Reduced Without Phenol Red: for sensitive cell lines and use of colour detection
OkaMatrix implanted in vivo can last up to one week before being degraded.
Yes, cells embedded in OkaMatrix can be fixed using 2% paraformaldehyde (PFA) for 48-72 hours.
Special Program FAQ
Unfortunately, we do not allow accounts to be created using personal email addresses. Only institutional email addresses, such as those from your university or company are allowed.
When you create a new gelmaco user account, we start preparing your free sample right away. Samples will be sent to the address used when registering your gelmaco account. Depending on your location, samples can take up to 4-6 weeks to reach your destination. If you would like to have your sample sent to a different address, or have not received your sample after 6 weeks, please email rewards@okasciences.com.
If you earned a free sample when your referral link was used, please email rewards@okasciences.com to let us know you’d like it sent to you. Alternatively, after ten referrals a GelMA team member will notify you via email that you qualify for a $500 gift card from one of our selection of retailers (Starbucks, Amazon etc.).
Every 4 points can be redeemed for $1 off your purchases. This means that 1,200 points are worth $300 in GelMA. Alternatively, if you collect 12,000 points, you can redeem these 12,000 points for a $500 gift card from one of our selection of retailers (Amazon, Starbucks etc.).
We are always adding new awards to give you more options when redeeming your points, so stay tuned!
We know we have amazing products, and our Ambassadors partner with us to introduce OkaGel and OkaMatrix to more researchers around the world.
There are many benefits to becoming an Ambassador. Our Ambassadors get access to exclusive discounts and earn extra points when friends they refer make purchases. Our Ambassadors also receive free company merchandise and other awesome perks!
You earn points on all of your purchases. You’ll earn one Okascience point for every dollar you spend.
Become an Ambassador and earn more points when the friends you refer make purchases.
We’re always here to help. Just send us a message at support@okasciences.com and we’ll get back to you as soon as we can.
GelMA FAQ
Heltmann-Meyer et al. (2021) demonstrated GelMA is a slowly degrading material which allows for long-term use in vivo – GelMA maintains volume and physical characteristics for 4 weeks[1]. This group used the arteriovenous loop (AVL) model with 10 wt% GelMA with1 wt% LAP photoinitiator. A PTFE chamber was filled halfway with the GelMA solution and crosslinked for 30s with 395-400nm light (layer thickness ~2.5mm after crosslinking). The in vivo arteriovenous loop placed on top and another layer of GelMA deposited on top and crosslinked as before. Approximately 1 mL of GelMA used in total. The construct was explanted 2 and 4 weeks later and there were no significant differences in weight or morphology.
[Shie et al., 2020] conducted accelerated GelMA degradation studies using collagenase. When using collagenase to increase the rate of degradation, higher concentrations of GelMA degrade more slowly than lower concentrations. All (5%, 10% GelMA) but one concentration of GelMA (15% GelMA) had constant degradation rates. Increased methacrylate (MA) crosslinks in higher concentration of GelMA hypothesized to be responsible for slower degradation rate ascrosslinks are resistant to collagenase. Mechanical and degradation properties could be easily fine-tuned by adjusting the ratio of gelatin and MA. “Our results demonstrated that the tensile strengths and completely enzymatical degradation periods of the GelMA hydrogels can be tuned in ranges between ~18 kPa to ~90 kPa and 7 to 14 days, respectively, by adjusting the concentration of the GelMA prepolymer.”
Image: Degradation plot. The hydrogels were soaked in 2 units∙mL-1 of collagenase solution for 2, 4, 12, 24, 72 h, and 1 and 2 weeks
GelMA degradation can be controlled using MMP inhibitors to reduce the rate of degradation, and collagenases to increase the rate of degradation. in vitro enzymatic degradation of GelMA hydrogels by type I and type II collagenases (also known as MMP-1 and MMP-8, respectively) proceeds at accelerated rates (Yue et al., 2015).
Pros:
- Limited antigenicity
- High degree of mechanical control
- Can be used in cell culture, manual organoid generation, bioprinting
- Liquid at room temperature and must be crosslinked for rigidity
- Consistent between batches
- Workable at room temperature
- Not derived from cancer: it can be used in translational and regenerative medicine.
Cons:
- Different bloom strength of gelatin used can affect strength of gel, must ensure you know what strength of gelatin was used
- Not previously widely used for organoid formation, however some successful examples are promising:
- Bovine colon organoids
- Analysis of the potential role of photocurable hydrogel in patient-derived glioblastoma organoid culture through RNA sequencing
- Clinically Amendable, Defined, and Rapid Induction of Human Brain Organoids from Induced Pluripotent Stem Cells
- Self-Assembled Hydrogel Microparticle-Based Tooth-Germ Organoids
– More papers are on the way. The below abstract results of successful kidney organoid formation with GelMA were communicated recently; Gelatin Methacryloyl (GelMA) as a Suitable Three‐Dimensional Extracellular Environment for the Derivation of hiPSC‐Derived Kidney Organoids
– Over-crosslinking can reduce cell viability
The pore size of GelMA can be controlled by changing the concentration of the GelMA solution. The higher the concentration of GelMA,porosity will be decreased and pore size will be smaller [Celikkin N et al., 2017].
The degree of substitution of amino groups was inversely proportional to pore size [Chen Y-C et al.,2012].
A study found that with an increase in cell density, the mechanical properties decreased, while the degradation and the pore size increased [Krishnamoorthy et al., 2019].
Image below: SEM images showing pore sizes after different hours of incubation for (a) 10% GelMA with no encapsulated cells and (b) 10% GelMA with a cell density of 5 × 106 cells/mL [Krishnamoorthy et al., 2019].
Image below: SEM images of GelMA hydrogels, showing the effect of the degree of methacryloyl substitution on the pore sizes of GelMA hydrogels [Yue et al., 2015]
Image below: SEM images of (A) 5 w/v%, (B) 15 w/v%, and (C) 25 w/v% photocrosslinkable GelMA hydrogels. Scale bars are 20 [Lee et al., 2015]
High porosity supports diffusion of oxygen and nutrients toward the cells and drainage of waste products from the matrix.
The usual thickness used for organoid formations is very workable for GelMA with no problems.
To achieve different levels of stiffness, higher concentrations of OkaGel can be used to increase stiffness of the material once crosslinked (as shown in the references above). The higher the concentration of OkaGel, the more crosslinks will be formed. You can also try increasing the time of light exposure to increase the stiffness of the crosslinked material.
