5 advances in tissue engineering you need to know about

Analysis: tissue engineering has potential to provide personalised healthcare, grow tissues and organs in the lab, as well as reduce organ donor waiting lists

We often hear about ’tissue engineering’ as a rapidly expanding field of science which holds significant promise in revolutionising healthcare. Tissue engineering has amazing potential to provide personalised healthcare, grow tissues and organs in the lab, as well as reduce organ donor waiting lists. This is a particularly important endeavour as it is estimated that there are currently over 700 patients in Ireland alone on donor waiting lists.

With such great promises, what exactly is tissue engineering? Tissue engineering is an interdisciplinary science which encompasses fields such as engineering, biology and chemistry, with the overall aim to replicate and/or restore damaged tissues and organs.

Amongst the ever expanding scope of research in this field, these are some of the most promising tissue engineering breakthroughs you need to know about:

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From RTÉ Radio 1’s The Late Debate, how will the Human Tissue Bill work?

Scaffolds

Scaffolds are constructed to act as supporting structures to provide a regenerative environment to the surrounding cells and tissues. In the development of such scaffolds, 3D printing of biomaterials has been heavily explored as it provides greater control over the scaffold microstructure. Recent advancements in this area reported 3D printing resolutions as low as 20-100 microns.

To put this into perspective, the thickness of a human hair is around 70 microns! Such fine printing resolutions allow for the creation of complex scaffold architecture in a layer-by-layer fashion. Bioprinting even further pushes the capabilities of 3D printing by combining biomaterials with cells to create a bio-ink. For example, recently a direct replica of a human ear has been 3D printed and implemented clinically.

Immune response

Traditionally, apart from long waiting lists, organ transplantation has the disadvantage of possibly being rejected by the patient’s body as it can recognise the donated organ as foreign. To avoid this, immunosuppressant medication is given to the patient, but often the patients will be required to take this medication for the rest of their lives. Impacting the immune system has several disadvantages, for example leading to greater risk of infections and the difficulty in fighting infections effectively.

Tissue engineering could be utilised to overcome this immune rejection of transplanted tissues or gene therapies and the need for immunosuppressants by combining the biomaterial scaffolds with cells taken from the patient themselves. When implanted, the body will recognise the same genetic material of the cells and not reject the scaffold. Further, biomaterials and cell based therapies can also be engineered to modulate the immune response in desired and controlled ways.

Stem cells

Until recently, cells used in tissue engineering strategies have relied on established primary cell lines, though over the years the use of embryonic stem cells has grown in interest. Embryonic stem cells originate from an embryo during the early stages of development, usually at four to seven days post fertilisation. These cells are considered pluripotent, meaning that they can differentiate and generate into cells of any type. Though with such great potential, their successful use in research has often been questioned ethically, as most of the supply of embryonic stem cells is derived from discarded in-vitro fertilisations (IVF).

To overcome such challenges, researchers have started to shift their attention to multipotent adult stem cells. Traditionally, these cells can develop into more than one cell type but are much more restricted in their differentiation capabilities than the embryonic stem cells. Recently, research on cellular reprogramming to induce adult stem cells to behave like pluripotent stem cells has been ongoing. The use of such cells would overcome the difficulty in procuring the stem cells as they can be taken from the patient’s bone marrow, blood, or adipose tissue, hence limiting the ethical and moral concerns.

Microfluidics

Applications of microfluidics in tissue engineering is another promising emerging technology. Microfluidic systems use small channels and devices to manipulate fluids, cells, and other biological materials at a microscopic scale, allowing for the creation of precise and controllable microenvironments which can mimic the complex biochemical and physical properties of native tissues, for example by mimicking functional blood vessels or liver tissue. This technology can also be used to create organ-on-a-chip models, which can evaluate the effects of drugs, toxins, and disease progression of different organs and their interactions with each other in a more realistic and reproducible way compared to traditional in-vitro models.

Non-viral vectors

Traditionally in gene therapy strategies, the delivery of new genetic material/genetic editing tools into specific cells is carried out by means of vectors. Viral vectors include viruses, and although successful to date, these can carry risks of dangerous immune responses in the body. However, new studies have reported on utilising non-viral vectors such as cationic liposomes, polymers and peptides with higher success rates. This approach can also be combined with tissue engineered scaffolds or nanoparticles which are designed to act as ‘carriers’ of the therapeutic drugs into the cells. This provides a localised and targeted approach that minimises adverse reactions such as immune response rejection, based on patient clinical needs.

In the coming decades, we will begin to see increasing implementation of tissue engineering strategies in our medical fields, transforming tissue engineering from a science fiction idea into reality.

The views expressed here are those of the author and do not represent or reflect the views of RTÉ