Guix, M. | Search bioRxiv

bioRxiv2020

Monitoring the collective behavior of enzymatic nanomotors in vitro and in vivo by PET-CT

Enzyme powered nanomotors hold great potential for biomedical applications, as they show improved diffusion and navigation within biological environments using endogenous fuels. Yet, understanding their collective behavior and tracking them in vivo is paramount for their clinical translation. Here, we report on the in vitro and in vivo study of swarms of self-propelled enzyme-nanomotors and the effect of collective behavior on the nanomotors distribution within the bladder. For that purpose, mesoporous silica nanomotors were functionalized with urease enzymes and gold nanoparticles. Two radiolabeling strategies, i.e. absorption of 124I on gold nanoparticles and covalent attachment of an 18F-labeled prosthetic group to urease, were assayed. In vitro experiments using optical microscopy and positron emission tomography (PET) showed enhanced fluid mixing and collective migration of nanomotors in phantoms containing complex paths. Biodistribution studies after intravenous administration in mice confirmed the biocompatibility of the nanomotors at the administered dose, the suitability of PET to quantitatively track nanomotors in vivo, and the convenience of the 18F-labeling strategy. Furthermore, intravesical instillation of nanomotors within the bladder in the presence of urea resulted in a homogenous distribution after the entrance of fresh urine. Control experiments using BSA-coated nanoparticles or nanomotors in water resulted in sustained phase separation inside the bladder, demonstrating that the catalytic decomposition of urea can provide urease-nanomotors with active motion, convection and mixing capabilities in living reservoirs. This active collective dynamics, together with the medical imaging tracking, constitutes a key milestone and a step forward in the field of biomedical nanorobotics, paving the way towards their use in theranostic applications.Competing Interest StatementThe authors have declared no competing interest.View Full Text

bioengineering↗

bioRxiv2020

3D-printed drug testing platform based on a 3D model of aged human skeletal muscle

Three-dimensional engineering of skeletal muscle is becoming increasingly relevant for tissue engineering, disease modeling and bio-hybrid robotics, where flexible, versatile and multidisciplinary approaches for the evaluation of tissue differentiation, functionality and force measurement are required. This works presents a 3D-printed platform of bioengineered human skeletal muscle which can efficiently model the three-dimensional structure of native tissue, while providing information about force generation and contraction profiles. Proper differentiation and maturation of myocytes is demonstrated by the expression of key myo-proteins using immunocytochemistry and analyzed by confocal microscopy, and the functionality assessed via electrical stimulation and analysis of contraction kinetics. To validate the flexibility of this platform for complex tissue modelling, the bioengineered muscle is treated with tumor necrosis factor to mimic the conditions of aging, which is supported by morphological and functional changes. Moreover, as a proof of concept, the effects of Argireline(R) Amplified peptide, a cosmetic ingredient that causes muscle relaxation, are evaluated in both healthy and aged tissue models. Therefore, the results demonstrate that this 3D-bioengineered human muscle platform could be used to assess morphological and functional changes in the aging process of muscular tissue with potential applications in biomedicine, cosmetics and bio-hybrid robotics.

bioengineering↗