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

Abstract

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.

Nanocellulose Hybrids with Metal Oxides Nanoparticles for Biomedical Applications

“…The stiffness range of the BC/Fe 3 O 4 hybrids (0.0025–0.04 GPa) was close to the values measured for both large arteries and veins of human cerebral vessels. A residual elastic straining effect similar to the one characteristic to biological tissues (e.g., tendons, blood vessels, ligaments) was also observed [ 97 ].…”

“…Cerebral aneurysms are the most critical events in cerebral trauma and surgical conventional treatments have low success rate [ 95 ]. Pavon et al developed an alternative technique for neuro-endovascular reconstruction [ 95 , 96 , 97 ]. They used a co-precipitation-based method to functionalize bacterial cellulose hydrogel with Fe 3 O 4 NPs.…”

“…Cellulose functionalization was performed by impregnating BC membranes with FeCl 3 ·6H 2 O and FeCl 2 ·4H 2 O solutions at 80 °C, under nitrogen flow and vigorous stirring accompanied by ammonium hydroxide (NH 4 OH) addition to form Fe 3 O 4 NPs inside the BC [ 96 ]. The surface of magnetic NPs used to develop magnetic materials for tissue regeneration should be modified for increased biocompatibility because plain magnetic NPs could cause genotoxicity and cells necrosis [ 97 ]. Different solutions were tested for improving biocompatibility.…”

“…Different solutions were tested for improving biocompatibility. In one attempt, oleic acid was added into the ferrofluid used for BC impregnation during the heating stage [ 97 ]. SEM images indicated that the magnetic NPs had an aggregation tendency, most likely due to the polar nature of fatty acid functional groups on their surface.…”

Nanocellulose in Biotechnology and Medicine: Focus on Skin Tissue Engineering and Wound Healing

“…In experiments in vitro, magnetic BNC coated with polyethylene glycol proved to form suitable scaffolds for porcine VSMCs, showing minimum cytotoxicity and supportive effects on cell viability and migration. This material also possessed suitable mechanical properties, and was considered to be promising for the treatment of brain vascular aneurysms [177,178]. Harmonic Generation (SHG) imaging, the MSCs on BNC scaffolds produced a mature type of collagen I and showed activity of alkaline phosphatase [179].…”