In situ Study Unravels Bio‐Nanomechanical Behavior in a Magnetic Bacterial Nano‐cellulose (MBNC) Hydrogel for Neuro‐Endovascular Reconstruction

• Published in: Macromolecular bioscience 2019-02, Vol.19 (2), p.e1800225-n/a
• Main Authors: Pavón, Juan Jose, Allain, Jean Paul, Verma, Devendra, Echeverry‐Rendón, Mónica, Cooper, Christy L., Reece, Lisa M., Shetty, Akshath R., Tomar, Vikas
• Format: Article
• Language: English
• Subjects: Aneurysm; Aneurysms; Aqueous environments; Biocompatibility; Biopolymers; Blood vessels; Brain; Cardiovascular system; Cellulose; Deionization; Endovascular coiling; Head injuries; Hydrogels; Implants; Indentation; Iron; Mechanical properties; Mechanical tests; Membranes; Modulus of elasticity; nanocellulose; nanomechanics; nanometrology; Nanoparticles; Orifices; Reconstruction; Substrates; Surgery; Surgical implants; Thrombosis; tissue engineering; Traumatic brain injury; vascular reconstruction
• ISSN: 1616-5187; 1616-5195
• DOI: 10.1002/mabi.201800225

Surgical clipping and endovascular coiling are well recognized as conventional treatments of Penetrating Brain Injury aneurysms. These clinical approaches show partial success, but often result in thrombus formation and the rupture of aneurysm near arterial walls. The authors address these challenging brain traumas with a unique combination of a highly biocompatible biopolymer hydrogel rendered magnetic in a flexible and resilient membrane coating integrated to a scaffold stent platform at the aneurysm neck orifice, which enhances the revascularization modality. This work focuses on the in situ diagnosis of nano‐mechanical behavior of bacterial nanocellulose (BNC) membranes in an aqueous environment used as tissue reconstruction substrates for cerebral aneurysmal neck defects. Nano‐mechanical evaluation, performed using instrumented nano‐indentation, shows with very low normal loads between 0.01 to 0.5 mN, in the presence of deionized water. Mechanical testing and characterization reveals that the nano‐scale response of BNC behaves similar to blood vessel walls with a very low Young´s modulus, E (0.0025 to 0.04 GPa), and an evident creep effect (26.01 ± 3.85 nm s−1). These results confirm a novel multi‐functional membrane using BNC and rendered magnetic with local adhesion of iron‐oxide magnetic nanoparticles. A bacterial nanocellulose hydrogel is designed magnetic to recruit magnetized endothelial cells asymmetrically near brain aneurysm defects to locally reconstruct the failed vessel wall. This magnetic hydrogel adjusted to the local hemodynamic environment and its nano‐mechanical function was tested in situ under prototypical fluid conditions. Its structure combines the resilience of the hydrogel and the physical magnetic forces provided by magnetic nanoparticle density gradient.