🧬 A Dynamic Bioprinting Hydrogel Made From…Crabs?

Chitosan-Based Biomaterials for 3D Bioprinting, Tissue Regeneration, and Drug Delivery

This month, we sat down with Dr. Hafez Jafari. Dr. Jafari is a postdoctoral researcher in biomaterials at the University of Brussels.

He began his journey into the world of 3D culture during his master’s thesis in 2016. Dr. Jafari studied chemical modification of cellulose nanocrystals to enhance stem cell-driven bone regeneration. Later, during his PhD, he developed adhesive hydrogels from natural sources like chitosan for wound healing and bleeding control.

In 2023, as a postdoctoral researcher at Ghent University, he worked on nanozyme nanomaterials that mimic natural enzymes to improve diabetic wound healing by addressing inflammation and other complications.

Currently, he leads a proof-of-concept project at the University of Brussels, developing chitosan-based biomaterials for 3D bioprinting, tissue regeneration, and drug delivery. These materials are designed for 3D printing organ models used in drug testing and studying cell-material interactions within a 3D matrix.

Transforming Chitosan into a 3D Innovation Platform

Describe your current proof of concept project. Do you see your research evolving into products for specific applications?

Dr. Jafari: The proof of concept is about developing raw material for 3D bioprinting. It’s not tied to a specific application yet, but it can be used in wound care. It could also be used for creating 3D models for drug testing, and possibly for tissue transplantation, although we’re still far from that.

Right now, the focus is on expanding the portfolio of biocompatible biomaterials that can work with cells for different types of applications.

Is your chitosan-based biomaterial meant to be an alternative to existing bioprinting gels?

Dr. Jafari: Let me give a brief introduction to chitosan. Chitosan is a natural biopolymer derived from chitin, which is found in the shells of crustaceans like shrimp, crabs, and fungi. We have both animal-based and non-animal-based sources available.

It’s an interesting biomaterial because of its inherent biological properties. It’s:

• antibacterial
• antioxidant
• anti-inflammatory
• biocompatible
• biodegradable

That means it has potential for a range of applications, like tissue regeneration and bone healing.

But it has some limitations. The main one is poor solubility. It’s not very soluble in physiological conditions, and it needs an acidic medium. That makes it difficult to use in applications like 3D bioprinting, which need physiological conditions where cells can thrive.

It can also be used in different types of product formats like films, hydrogels, fibers, or sponges, depending on the application. That’s why we already have quite a lot of chitosan-based commercial products, especially for wound care. In our current project, we’re chemically modifying chitosan to address these limitations.

Chitosan in the form of a hydrogel has a brittle structure due to its intermolecular hydrogen bonds. We’re trying to increase the flexibility, improve the viscosity and viscoelastic properties, and, more importantly, address the low water solubility and printability.

In the lab, I experienced these limitations because I used to work with chitosan during my PhD. I thought it would be great to address the limitations of chitosan and use it for 3D bioprinting.

What specific problems with alternative hydrogels led to the search for a better solution?

Dr. Jafari: I wouldn’t say it was a specific limitation with other hydrogels. But the fact is, bioprinting technology is advancing quickly, while the materials used for 3D printing are lagging behind. We have different types of printing: volumetric, extrusion-based, and digital light processing, but not many materials can be used for these.

I want to expand the portfolio of materials that can be used for different types of printing platforms.

Building 3D Skin Models for Chronic Wound Testing

What would be the first product you’d like to see come out of this research?

Dr. Jafari: At this point, it’s more investigation and exploring the possible opportunities. One possible product could be chemically modified chitosan that can be used for 3D bioprinting, like a bioink with unique properties that aren’t currently on the market.

Could you run me through one of the types of assays that you perform when it comes to the 3D model side?

Dr. Jafari: One of the most advanced assays I am developing now is to see the effect of nanozymes in a 3D model of inflammatory skin tissue. The idea is to build a model that can mimic what’s happening in chronic wounds in diabetic patients, where:

• inflammation
• oxidative stress
• hypoxia

are quite challenging for healing. And that’s the major problem.

So, we start by using this chitosan-based polymer material incorporating primary human dermal fibroblasts and keratinocytes, because these two cells are the key players in skin repair. Once the printed construct is stable and the cells are well distributed, we induce oxidative stress or inflammation using external stimuli such as hydrogen peroxide or inflammatory cytokine.

These stimuli can mimic the chronic wound environment, where cells are exposed to high levels of reactive oxygen species and inflammatory segments. Then we introduce our nanozyme with enzyme activity to see if this nanozyme can alleviate the hypoxia, produce oxygen, and affect the cells in 3D environment.

There are some challenges, specifically in terms of imaging. When working with 3D systems, like bio- fluorescence imaging systems, it’s challenging for some specific staining. For example, checking intracellular oxygen or ROS levels, such as superoxide anion, cell morphology, etc. in 3D environments.

Our goal is to see if this model can be used to validate the therapeutic efficiency of this nanozyme in the wound model and whether it can restore balance, reduce oxidative damage, and if it’s compatible with a 2D system or not.

Industry Challenges: Why 3D Models Aren’t Mainstream Yet

What is the industry getting wrong when it comes to developing and scaling 3D in vitro platforms for broader adoption by pharma or clinics?

Dr. Jafari: One common issue is that when we talk about 3D in-vitro models, we often treat them as one thing, but there are many types, such as spheroids, organoids, hydrogel-based systems, bioprinted tissue models and organ-on-a-chip microfluidic devices. Each of them has strengths and limitations.

At times, the industry treats them like interchangeable tools, but they really require different handling, materials, and validation. In my opinion, the major challenge is the lack of standard methods. There isn’t an agreed protocol on how to make 3D models–how long to culture the cells, or how to measure outcomes like viability, inflammation, or function. This makes it very hard to compare results between labs and even harder to integrate these models into drug testing pipelines for big pharma companies.

For bioprinting, the industry often underestimates how sensitive the system is. Even small changes in viscosity, pH, temperature, or printing parameters can change how cells behave. If we can’t reproduce the system reliably, it’s not easy to adopt. To move forward to larger scale adoption, we need models that are simple, reproducible, and compatible with automation. We need standard methods that can be used across labs and companies.

How can we work towards standardization in 3D models, given that there isn’t a one-size-fits-all solution?

Dr. Jafari: In my opinion, regulatory bodies that approve methods can provide a roadmap. For example, the FDA recently announced phasing out animal tests for monoclonal antibodies and other drugs, and they provided a roadmap for using AI models, organ-on-a-chip, microfluidics, and 3D printed models for drug testing.

I believe other regulatory bodies will also move towards non-animal testing in the future. A close collaboration between industry and academia is essential because each lab has its own methods. There’s no magic solution yet. All parties — academia, startups, and industry — need to work closely together.

If you had a magic wand and could solve the most frustrating challenge in your current work, what would that challenge be exactly?

Dr. Jafari: One magic solution for me would be ready-to-use reproducible tissue models that are tissue-specific and disease-specific. For example, if I want to test drugs for cardiovascular disease, having a miniature cardiac tissue that mimics human biology and allows easy testing would be magic. This could solve many challenges both in small laboratories and big pharma companies.

Since there isn’t a ready-to-use product you can pull out of the freezer, thaw, and use. What will you do instead?

Dr. Jafari: Our option is to do 3D printing of the organs with specific cell lines that can mimic the biology of the tissue. Once the tissue is stable, we have our organ model ready.

But there’s a lot of challenge with this type of modelling. Starting from raw materials, printing, encapsulating the cells, including growth factors, especially if you want to work with primary cells, it’s even harder.

What’s the one thing you absolutely love doing in your work?

Dr. Jafari: I come from an engineering background. I did my bachelor’s and master’s in chemical engineering. I really enjoy using engineering and chemistry to solve biological problems. The most exciting moment was when we designed a new material/new chemistry in the lab that accurately helps cells better mimic what we see in the body. That connection between the chemistry and biology really keeps me motivated. For example, how we can treat materials to help with inflammation, or how the viscoelastic properties of a material affect cell growth. How we can engineer materials to mimic the extracellular matrix for better cell growth and proliferation excites me.

Are there specific partnerships or collaborations that you are looking for right now? 

Dr. Jafari: We’re looking for laboratories that are equipped with 3D bioprinting or who enjoy working on 3D models for drug testing. They can try our materials to see if they fit their needs and give us feedback about their unmet needs as potential customers. Also, we are open to working with clinical groups focused on wound healing or tissue regeneration, who are interested in testing these materials as a more realistic model for chronic wounds or inflammatory tissue. 

How do you keep up with the most recent developments in your field, especially in 3D cultures? What have you found to be the best resources, newsletters, conferences, and events that you try to attend or follow regularly? 

Dr. Jafari: The main way I follow recent work is through conferences. The last one I attended was the World Bioprinting Congress (WBC) in South Korea, where many people from bioprinting came together.  I also keep up by reading papers and articles. I like the idea of your newsletter that brings people working in one direction together. It’s cool to see what others are doing, their challenges and needs. It can lead to new ideas or collaborations, and I really like it. 

If you were to look optimistically into the future, where would you like to see the tissue regeneration and organ transplantation industry be in 30 years? 
 

Dr. Jafari: I cannot exactly predict what we will have in 30 years, but I guess for simpler tissue models like skin, cartilage, or cornea, it would be easier in the next 10-20 years. But for more complex tissues or organs, maybe it takes 30-40 years. The final goal of 3D bioprinting is organ transplantation, but an organ is not just a matrix and cells. It’s more complex, due to cellular interactions, growth factors, and the vascular system, which is quite complex. But to me, science is step-by-step. These small steps need to be taken to reach the final goal. 

I cannot guarantee what will happen in 30 years, but I think we will see really cool things because technology is accelerating. I mean, five years ago, we didn’t believe we could have AI chatbots you can ask anything. So even cooler things are coming. To me, the speed of technological acceleration is getting faster, and I believe in 30-40 years we could have patient-specific organ transplantation – the patient’s own cells to personalize the organs that need to be transplanted. That could be possible.

What’s your most recent publication, and will there be any new ones coming out soon from this research? 

Dr. Jafari: Yes, during my post-doctoral at Ghent, I used to work on enzyme-mimicking activity called nanozyme. We submitted it recently. We did research on this unique design of nanozyme with a corset structure which can produce oxygen and reduce inflammation. It can also consume glucose, and from the glucose produce oxygen, which can relieve hypoxic conditions. We also did simulations showing how they behave in biological fluids in the body and what the effects are.  

That one will be published soon. I really like this project because it was one and a half years of full-time work.  

You can find him here:

LinkedIn: Hafez Jafari