The meso scale: bridging the macro & the micro

The macrovascular part of the B2B device is a network aimed at replicating the key features of vascular network found in our body – therefore it includes a smooth transition from relatively large vessel down to micro-vessels.

“To cover the mesoscale that lies in between the macro and the micro scales, that’s where the real challenge is. In B2B, we will try to cover this gap and bridge vessels of few mm with those in the sub-mm scale”, explains Prof. Moroni, head of the Complex Tissue Regeneration department at MERLN and responsible for the development of the macro-network in the B2B device.

Indeed, the current technology allows us to build wonderful scaffolds above the mm scale, and, thanks to the biological angiogenesis, we can well reproduce micro-vessels or capillaries that are below the tens of microns scale. In B2B instead, the network will start from vessels in the order of a few mm of diameter and it will go down to reach a scale of tens of microns. According to Prof. Moroni, “This is a challenge not only from the technological point of view but also from the physiological point of view, as we need to ensure that the bio-fabricated network maintains a correct flow in all the sub-branches of the network.”

He continues: “It’s already quite difficult to have a single vessel which is physiologically functional in the order of few mm.” For example, an unmet clinical need is the creation of an artificial coronary artery (5 mm), for which the solutions developed so far still present some shortcomings as they tend to form blood clots. “We start from this challenge, but in B2B we expand it to embrace multiscale complexity by aiming to manufacture an array of branching vessels of different size.”

Another challenging aspect the B2B technology is the connection between the macro-network and the micro-vessel, the latter created by the group of A. Banfi at University of Basel (read the news here). “It might sound logical but it’s harder than one can imagine, because the two parts have a different nature: one is biological (the capillaries) and the other one comes from a bioengineering approach – therefore, their compatibility and communication is not granted.” The two systems need to merge and create a continuous lumen that runs from the macro to the micro.

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