Photocrosslinking Bioinks Customization Services

CD BioSciences is a biotechnology company that provides a high resolution 3D printing technology platform called 3Dmicroflu™ for biological 3D printing. In addition, we also provide high quality bioinks products and bio-ink customization services suitable for all types of 3D printers. If you don't find a bioink that meets your project needs in our product range, please contact us now for expert customization services. Below you will find an overview of CD BioSciences' customization services based on photocrosslinking bioinks customization services in the chemical crosslinking method.

The process of linking the chains of polymer molecules to each other through photochemical reactions to form a web-like structure is called photocrosslinking. Photocrosslinking ink materials have been commonly used in 3D printing because of the ease of operation and the possibility of remote control. In the presence of photoinitiators and light, photocrosslinked bioinks are crosslinked by chain-growth, step-growth and redox reactions mechanisms.

Fig. 1. 3D printing of vascular channels using agarose fibers in methacrylate-gelatin photocrosslinked hydrogels. (Luiz, E, et al., 2014)

(1) Chain-Growth Crosslinking: In this cross-linking process, light radiation generates free radicals by breaking down the photoinitiator added to the bioink. The generated radicals react with the functional groups of the polymer and bind them together to form a three-dimensional network structure. This cross-linking strategy mainly involves the formation of irreversible bonds between two polymer chains. Free radical polymerization of (meth)acrylate-based monomers is the most common method for 3D bioprinting of photo-crosslinkable structures.

(2) Step-Growth Crosslinking: In this crosslinking process, bio-orthogonal bonding reactions are used as an alternative crosslinking mechanism to chain growth polymerization. These reactions are mainly carried out by stepwise polymerization reactions under light irradiation. Thiol-ene click chemistry is based on the dimerization reaction of thiols with reactive alkene groups to form homogeneous hydrogel networks. The alkenyl groups commonly used in this cross-linking method are acrylates, methacrylates and vinyl ethers.

(3) Redox-Based Crosslinking: Oxidation-reactive materials such as phenol-containing polymers can be photooxidatively cross-linked by the realization of reactive groups. In this process, photolysis of oxygen in the presence of a photosensitizer generates singly linear oxygen and free radicals. The radicals formed in this step lead to the conversion of phenolic compounds into different forms of radicals that can rapidly bind pairs of reactive groups together to form three-dimensional network structures.

CD BioSciences' custom service process for photocrosslinking bioinks

As the most widely used and adapted type of bioink for the most common 3D printers, customization of photo-crosslinked bioinks is also what CD BioSciences does best. For customization of photo-crosslinked inks, our professional team focuses on the following aspects.

• Selection of light source, exposure time and light intensity

The photocrosslinking process can be carried out in the form of UV, laser or visible light. However, when photo-crosslinking is applied to biological 3D printing, cell viability needs to be taken into account. UV light can damage the cell structure to some extent, so using visible light is relatively most appropriate and safe. After determining the wavelength of the light source, what needs to be determined by further research are parameters such as exposure time and light intensity, which are also coordinated mainly based on cellular activity.

• Selection of photoinitiator type and concentration

The photoinitiator is the most indispensable part of the photocrosslinking process, which mainly affects the mechanical properties and cellular behavior of the bio-3D printed structures. First select a suitable photoinitiator with good biocompatibility, and subsequently find the right concentration formulation to coordinate the stiffness and cellular activity through testing. CD BioSciences currently offers two types of photoinitiators for you to choose from, including LAP and ruthenium. They have little effect on cellular behavior, and the concentration of the formulation used can be adjusted based on the mechanical properties.

• Consider adding other polymers to improve the printing performance of photocrosslinking inks alone

The addition of other polymers to photocrosslinked bioinks often improves their processability and crosslinking properties. It is the task of CD BioSciences to find the right additions and the corresponding ratios. In addition, photocrosslinking bioinks with functionalized polymers can also improve printing properties to some extent.

In CD BioSciences' customization service for photo-crosslinked inks, we will use cellular activity and printability as the main reference basis to provide you with reasonable bioinks customization.

*Customization and Delivery Process

CD BioSciences has been committed to providing one-stop bioinks customization services and guarantees

(1) immediate response to your online inquiry.

(2) customization solutions on demand within 5-7 days.

(3) daily feedback on the customization process.

If you are interested in our bioinks customization services, please contact us now for exclusive services. All services are available on a 24/7/365 basis.

Reference

1. Luiz, E.; et al. Hydrogel bioprinted microchannel networks for vascularization of tissue engineering constructs. Lab Chip. 2014, 14(13): 2202.