Ref No: REP-VL350000
Date: 08-FEB-2023
Author: MSL, VK, EP. Version: 6

RECONSTITUTION PROTOCOL

PhotoGel® 50% DS
This is a suggested procedure, please adjust it according to your experimental
needs. To maintain the sterility of the product, work under sterile conditions.

Protocol aim

Materials needed

The aim of this protocol is to provide instructions on
how to reconstitute PhotoGel® 50% DS (lyophilizedGelMA) to your desired concentration using
Reconstitution Agent P. Addition of a photoinitiator(PI) and use of 365 or 405 nm LED modules ensurestable and controlled photocrosslinking of GelMA
constructs for 3D cell culturing. The obtained GelMAhydrogel can be used as a bioink on its own or as acomponent in other bioink formulations.

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Stability: PhotoGel® 50% DS reconstituted in
Reconstitution Agent P is stable for at least 6 months
without a photoinitiator, and 4 months with aphotoinitiator, if stored at 4-8°C protected from light.

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PhotoGel® 50% DS (500 mg)*
Reconstitution Agent P* or an alternative bufferof choice
Photoinitiator*
Syringes
0.22 µm sterile syringe filter
15 mL Falcon tube or equivalent
Female/female Luer lock adaptors*
Amber cartridge, 3cc*

*The product can be purchased in the CELLINKshop at www.cellink.com/shop/.

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Protocol
This protocol describes the reconstitution of 500 mg of PhotoGel® 50% DS to obtain GelMA bioinks of different
concentrations. All PhotoGel® 50% DS concentrations are calculated as the weight of PhotoGel® 50% DS pervolume of Reconstitution Agent P (w/v).

1.

Preparing PhotoGel® 50% DSMATERIALPhotoGel® 50% DS

DESCRIPTION•

2.

Take PhotoGel® 50% DS from storage and let it reach room temperature.

Preparing Reconstitution Agent P with PI

MATERIAL
Reconstitution Agent P
PI, for example LAPSyringe
0.22 µm sterile syringe filter
15 mL Falcon tube

DESCRIPTION•

Prepare 12 mL of a Reconstitution Agent P.

Note: Reconstitution Agent P is a specially designed buffer that maintains a physiologic pH in the final
GelMA bioink.
•Mix the desired amount of PI in the Reconstitution Agent P. Remember to protect all PI containing
mixtures from light. Ensure PI is properly dissolved before proceeding.
Note: LAP is used as the recommended PI for photocrosslinking at 405 nm and is used in the calculations
below (see Table 1 for suggested LAP concentrations). For other PI options, amounts may vary.
•Warm the PI solution to ~50°C. Sterile filter the PI solution into a sterile 15 mL Falcon tube using asyringe and 0.22 µm sterile syringe filter. Keep the solution at ~50°C.
Table 1. Suggestions of LAP concentrations for GelMA bioink.
LAP concentration in GelMA bioink

LAP mass for 12 mL of Reconstitution Agent P

0.10% (1 mg/mL)
0.25% (2.5 mg/mL)

12 mg
30 mg

3.

Reconstituting PhotoGel® 50% DS

MATERIAL
PhotoGel® 50% DS
PI solution (Reconstitution agent + PI)

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DESCRIPTION•••

Add your desired PI solution to the PhotoGel® 50% DS vial, see Table 2 for suggested GelMA bioink
concentrations.
Mix on a shaker table or rotator plate until fully solubilized. Keep warm (37-50°C) if possible (eg. place
your rotator in an incubator) to help with full solubilization.
Double check that the pH is in the 7.0-7.4 range since pH is important for the proper viscosity of thebioink. If needed, balance with small volumes of NaOH or HCl solutions.

Note: Be careful with adding NaOH since high pH degrades GelMA.
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Use the GelMA solution as it is or mix it with other components of choice.
Warm the GelMA solution at 37°C until it is liquid. Transfer the GelMA solution to syringes and aliquot
the volume if applicable.
Store at 4-8°C.

Table 2. Suggestions of final GelMA bioink concentrations for reconstitution of 500 mg PhotoGel® 50% DS.
Concentration of GelMA bioink (w/v)
5%
10%
20%

4.

Volume of PI solution needed
10 mL
5 mL
2 mL

Preparing the GelMA bioink

MATERIALSyringe
Female/female Luer lock connectors
Amber cartridge, 3cc

DESCRIPTION••Warm the needed amount of GelMA solution at 37°C until it is liquid. Transfer the GelMA solution fromthe syringe to an amber cartridge using a Luer lock connector.
See the Bioprinting Protocol GelMA Bioink for instructions on how to bioprint GelMA 10% with or without
cells.

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