MIT Researchers Develop Precise Lab-Grown Microvascular Networks

A research group has introduced a new technique enabling the precise engineering of blood vessels in laboratory settings, potentially paving the way for manufacturing transplantable human tissues and organs in the future.

Blood vessels, especially the capillaries with diameters as small as 0.005 millimeters—about 34 times thinner than a human hair—pose significant challenges in tissue engineering. These microvessels permit the passage of individual blood cells.

Vascular networks are essential for the viability of any lab-grown organ because they deliver oxygen and nutrients to tissues.

The innovation by a team at the Massachusetts Institute of Technology utilizes magnetic forces to gently stretch and pull vascular cells into desired positions. They designed a small chip containing lab-grown endothelial cells suspended in collagen gel, the primary protein forming bodily tissues. A tiny magnet embedded within the chip is controlled by several external magnets in three dimensions, allowing researchers to direct the growth of new blood vessels with high precision.

Mechanical engineer Ritu Raman from MIT explained, "Healthy tissues depend on organized vascular networks, but current protocols do not allow for creating such networks within engineered tissues." She added, "Being able to program vascular growth using physical signals could enable us to reproducibly fabricate engineered tissues that can be implanted to restore function after debilitating diseases or injuries."

The researchers managed to regulate the length and number of new vessels by adjusting the strength of the external magnetic pulling force. Raman noted, "The key finding is that cyclic stretching of blood vessels promotes the growth of new capillaries. Mechanical forces play a vital role in our bodies, and now we understand how to grow more or fewer vessels, shorter or longer ones, or vessels oriented in specific directions."

Although current methods allow 3D printing or Petri dish cultivation of blood vessels, these approaches lack the required precision.

To investigate underlying mechanisms, the team repeated experiments with genetically modified cells lacking the PIEZO1 gene, which regulates ion channels responsive to mechanical pressure. Disabling this gene reduced the number of formed vessels, confirming that activating these ion channels is crucial for blood vessel formation.

This technique is an advanced iteration of the approach the team previously applied to create artificial muscles and nerves. While still at the prototype stage, early results are promising. The next steps involve testing blood flow efficiency through the vessels formed on the chip, followed by cultivating real tissues around the vascular structures, starting with muscle tissue.