Publications

The properties of thiol-yne click polyethylene glycol (PEG)-based hydrogels, which can be tuned by controlling the cis and trans stereochemistry through the gelation conditions, have been investigated at the micro- and nanoscale using optomechanics, atomistic molecular dynamics (MD) simulations, and nanoindentation. Optomechanical measurements on thin films and computer MD simulations have shown that the trans hydrogel is less porous than the cis hydrogel, which is in agreement with both the swelling behavior and the pore size determined for macroscopic 3D hydrogel samples. On the other hand, results from optomechanical measurements using both static and dynamic modes, as well as nanoindentation profiles obtained for thin films adhered to glass substrates, reflect that the trans hydrogel is stiffer than the cis one. Overall, despite the few drawbacks of the techniques employed in this work, from a qualitative point of view, the properties of click PEG-based hydrogels at the micro- and nanoscale follow a behavior similar to that found for 3D macroscopic samples. Considering the wide range of mechanical properties of human tissues (e.g., Young's modulus ranges from 0.1 kPa to many tens of MPa) and the extensive use of hydrogels in applications such as tissue regeneration and tissue-specific drug delivery, the availability of a hydrogel with tunable properties opens the door to targeted biomedicine.

JTD Keywords: Algorithm, Elastic modulu, Ewal, Injectable hydrogels, Molecular dynamics, Molecular-dynamics, Nanoindentation, Optomechanical sensors, Polyethylene glycol hydrogels, Surface stress, Thiol-yneclick hydrogels

Recently, organoids have emerged as revolutionizing tools with the unprecedented potential to recreate organ-specific microanatomy in vitro. Upon their derivation from human pluripotent stem cells (hPSCs), organoids reveal the blueprints of human organogenesis, further allowing the faithful recapitulation of their physiology. Nevertheless, along with the evolution of this field, advanced research exposed the organoids' shortcomings, particularly regarding poor reproducibility rates and overall immatureness. To resolve these challenges, many studies have started to underscore the relevance of mechanical cues as a relevant source to induce and externally control hPSCs differentiation. Indeed, established organoid generation protocols from hPSCs have mainly relyed on the biochemical induction of fundamental signalling pathways present during kidney formation in mammals, whereas mechanical cues have largely been unexplored. This review aims to discuss the pertinence of (bio) physical cues within hPSCs-derived organoid cultures, while deciphering their effect on morphogenesis. Moreover, we will explore state-of-the-art mechanobiology techniques as revolutionizing means for understanding the underlying role of mechanical forces in biological processes in organoid model systems.

JTD Keywords: development, hpscs, mechanobiology, nephrogenesis, Activated ion-channel, Development, Extracellular-matrix viscoelasticity, Forces, Hpscs, Ips cells, Mechanical regulation, Mechanobiology, Nephrogenesis, Nephron progenitors, Organoids, Pluripotent stem-cells, Self-renewal, Substrate mechanics, Tissue

Chronic obstructive pulmonary disease (COPD) requires a multifactorial assessment, evaluating the airflow limitation and symptoms of the patients. The 6-min walk test (6MWT) is commonly used to evaluate the functional exercise capacity in these patients. This study aims to propose a novel predictive model of the major 6MWT outcomes for COPD assessment, without physical performance measurements.Cardiopulmonary and clinical parameters were obtained from fifty COPD patients. These parameters were used as inputs of a Bayesian network (BN), which integrated three multivariate models including the 6-min walking distance (6MWD), the maximum HR (HRmax) after the walking, and the HR decay 3 min after (HRR3). The use of BN allows the assessment of the patients' status by predicting the 6MWT outcomes, but also inferring disease severity parameters based on actual patient's 6MWT outcomes.Firstly, the correlation obtained between the estimated and actual 6MWT measures was strong (R = 0.84, MAPE = 8.10% for HRmax) and moderate (R = 0.58, MAPE = 15.43% for 6MWD and R = 0.58, MAPE = 32.49% for HRR3), improving the classical methods to estimate 6MWD. Secondly, the classification of disease severity showed an accuracy of 78.3% using three severity groups, which increased up to 84.4% for two defined severity groups.We propose a powerful two-way assessment tool for COPD patients, capable of predicting 6MWT outcomes without the need for an actual walking exercise. This model-based tool opens the way to implement a continuous monitoring system for COPD patients at home and to provide more personalized care.Copyright © 2022 The Authors. Published by Elsevier B.V. All rights reserved.

JTD Keywords: 6mwt, bayesian networks, copd, distance, exercise capacity, physical capacity, reference equations, severity, survival, wearables, 6mwt, Bayes theorem, Bayesian networks, Copd, Exercise test, Exercise tolerance, Heart-rate recovery, Humans, Physical capacity, Physical functional performance, Pulmonary disease, chronic obstructive, Walking, Wearables

The proper differentiation and threat of cancer rising from the application of induced pluripotent stem (iPS) cells are major bottlenecks in the field and are thought to be inherently linked to the pluripotent nature of iPS cells. To address this question, we have compared iPS cells to embryonic stem cells (ESCs), the gold standard of ground state pluripotency, in search for proteins that may improve pluripotency of iPS cells. We have found that when reprogramming somatic cells toward pluripotency, 1%-5% of proteins of 5 important cell functions are not set to the correct expression levels compared to ESCs, including mainly cell cycle proteins. We have shown that resetting cyclin A1 protein expression of early- passage iPS cells closer to the ground state pluripotent state of mouse ESCs improves the pluripotency and reduces the threat of cancer of iPS cells. This work is a proof of principle that reveals that setting expression of certain proteins correctly during reprogramming is essential for achieving ESC- state pluripotency. This finding would be of immediate help to those researchers in different fields of iPS cell work that specializes in cell cycle, apoptosis, cell adhesion, cell signaling, and cytoskeleton.

JTD Keywords: Self-renewal, IPS cells, Ground-state, C-MYC, Generation, Pathway, Disease, Mice, Link, P53