3D bioprinting

What is 3D bioprinting?

Three-dimensional bioprinting or 3D bioprinting is an emerging technology that uses 3D printing techniques to deposit biological material to create artificial tissues and organs.

Living cells and extracellular matrices can be ‘printed’ to create replacement organs, skin grafts, and intricate skin structures. 3D bioprinting, a form of bioengineered skin, has the potential to be used for disease modelling, personalised treatment, drug testing, and skin regeneration. The epidermal, dermal, and subcutaneous tissue layers of skin can be printed separately.

How does 3D bioprinting work?

3D bioprinting uses imaging data to create a precise digital model of the desired tissue or organ. The 3D printer then deposits living cells or composite materials layer by layer in a pattern that mimics the original organ.

Once the bioprinting process is complete, the tissue or organ is incubated in an environment that promotes cell maturation. The cells fuse and mature, eventually creating functional tissue or an organ that can be used for transplantation, grafting, or other purposes.

The raw materials that emerge from a 3D bioprinter can be broken down into three main components — cells, biomaterials, and growth factors:

• Cells such as skin, cartilage, bone, heart, liver, pancreatic, neural, and blood vessel cells can be 3D bioprinted
• Biomaterials such as hydrogels, decellularised extracellular matrix (dECM), or synthetic polymers are the structural foundation, supporting the cells
• The growth factors are proteins such as vascular endothelial growth factor (VEGF) and transforming growth factor-beta (TGF-beta) that stimulate cell proliferation and differentiation into the desired tissue.

What could 3D bioprinting be used for in dermatology?

Skin grafts

Synthetic, 3D bioprinted skin substitutes can be created for patients with burns, wounds, severely damaged skin, or other injuries that require skin grafts.

Skin substitutes containing human adipose-derived stem cells and human keratinocytes have been successfully used to treat diabetic wounds. They improved wound healing compared to traditional wound dressings.

Drug testing

Human skin models have been used to test the safety and effectiveness of new drugs and cosmetics, reducing the need for animal testing and accelerating the process of drug development.

Disease modelling

Skin models have been created to study specific diseases, such as atopic dermatitis (eczema), psoriasis, and skin cancer. The reproducibility of the 3D printed models may also help develop new treatments. Reported models have included:

• Psoriasis — creating a thick epidermis and an inflammatory cell infiltration
• Atopic dermatitis — reproducing the inflammatory response and barrier failure.

Personalised medicine

Skin models can be created with a disease state specific to an individual patient to develop treatment plans unique to the patient’s skin type and physiology. Patient-derived 3D skin models have been used to develop:

• Novel treatment for epidermolysis bullosa
• Immunotherapy for melanoma.

Wound healing

3D bioprinting can create a scaffold to implant into a chronic wound, promoting tissue regeneration.

• Investigations have shown improved wound healing in a mouse model.
• The creation of new blood vessels and human skin cells by a 3D-printed scaffold suggests that this approach can be used to treat a variety of skin injuries and diseases.

Non-dermatological applications of 3D bioprinting

Creating replacement organs

Once technical and ethical challenges have been overcome, 3D bioprinting using the patient’s own cells could eventually be used to create replacement organs for patients in need of a transplant, eliminating:

• The need for organ donors
• The potential for organ rejection
• The undesirable effects of immunosuppression.

Producing new healthy tissue

Sections of 3D bioprinted bone have already been successfully surgically implanted into humans. 3D bioprinted skin, cartilage, and blood vessels can be used to repair injuries or congenital defects. Living tissue with blood vessels has been 3D bioprinted and implanted into animals, creating experimental structures such as a jawbone, ear, and muscle.

Drug development

3D bioprinted models could be used to determine drug pharmacokinetics and pharmacodynamics. Researchers have created tiny models of the liver, heart, and kidney that proved accurate in predicting the toxicity of different drugs.

What are the potential benefits of 3D bioprinting?

• Reduced need for skin graft harvesting
• Improved wound healing
• Skin models for personalised medicine
• Research advances
• Reduced animal testing

What are the potential disadvantages of 3D bioprinting?

As 3D bioprinting is currently experimental, its disadvantages are not fully determined. They include:

• High cost
• Limited scalability due to the lack of suitable raw materials
• A limited range of printable materials
• Complex technical requirements, restricting the technology to a few specialised research centres and institutions
• Regulatory challenges: the lack of guidelines for standardised testing and ensuring safety are delaying development and commercialisation
• Ethical considerations to printing functional human organs.

What are the potential side effects and risks of 3D bioprinting?

Side effects and risks of 3D bioprinting may include:

• Safety concerns, such as the risk of contamination or immune rejection
• Lack of or improper function of the implanted tissue.

What are the contraindications with 3D bioprinting?

Contraindications to 3D bioprinting have not yet been determined.