User-driven walking assistance: first experimental results using the MyoSuit.

Wearable robots for the legs have been developed for gait rehabilitation training and as assistive devices. Most devices have been rigid exoskeletons designed to substitute the function of users who are completely paralyzed. While effective for this target group, exoskeletons limit their users' contributions to movements. Soft wearable robots have been suggested as an alternative that allows, and requires, active contributions from users with residual mobility.In this work, we first tested if the MyoSuit, a lightweight, lower-limb soft wearable robot, affected the walking kinematics of unimpaired users. Secondly, we evaluated the assistance delivered to a patient with a gait impairment.In our first study, 10 unimpaired participants walked on a treadmill at speeds between 0.5 and 1.3 m/s. We found that wearing the MyoSuit in its transparency mode did not affect the participants' walking kinematics (RMS difference of joint angles < 1.6°). Step length and the ratio of stance-to-stride duration were not affected when wearing the MyoSuit.In our case study with one spinal cord injured participant, the MyoSuit supported the participant to increase his 10 MWT walking speed from 0.36 to 0.52 m/s, a substantial clinically meaningful improvement.Our results show that the MyoSuit allows user-driven, kinematically unaltered walking and provides effective assistance. Systems like the MyoSuit are a promising technology to bridge the gap between rigid exoskeletons and unassisted ambulation.

Expanded skeletal stem and progenitor cells promote and participate in induced bone regeneration at subcritical BMP-2 dose.

The regeneration of large bone defects remains an unsolved clinical problem, which could benefit from recent findings on the biology of skeletal stem and progenitor cells. The elucidation of conditions to specifically control their dynamic and function will likely enable the development of novel treatment strategies. In this study, we aimed at dissecting the role of osteogenic cues and skeletal stem (SSC) and progenitor cell (BCSP) recruitment during biomimetic hydrogel-assisted bone regeneration. To do so, we employed a biomimetic synthetic hydrogel based on poly (ethylene glycol) (PEG), highly controllable and enzymatically crosslinkable. We show that hydrogel-released bone morphogenetic protein-2 (BMP-2) dose-dependently promoted the enrichment of both SSCs and BCSPs within bone defects. Furthermore, we demonstrate that prospectively isolated neonatal bone-derived, as well as expanded SSCs and BCSPs, differentiate into osteogenic cells and enhance the healing of bone defects by low BMP-2 releasing biomaterials. These results indicate that growth factor releasing materials should be designed to first augment the number of SSCs and BCSPs, followed by their osteogenic differentiation to potentiate the healing of bone defects. Additionally, we demonstrate that expanded SSCs and BCSPs are easily accessible cell sources that allow the study of novel bone healing regimen under controlled in vitro and in vivo conditions.

The Myosuit: Bi-articular Anti-gravity Exosuit That Reduces Hip Extensor Activity in Sitting Transfers.

Muscle weakness-which can result from neurological injuries, genetic disorders, or typical aging-can affect a person's mobility and quality of life. For many people with muscle weakness, assistive devices provide the means to regain mobility and independence. These devices range from well-established technology, such as wheelchairs, to newer technologies, such as exoskeletons and exosuits. For assistive devices to be used in everyday life, they must provide assistance across activities of daily living (ADLs) in an unobtrusive manner. This article introduces the Myosuit, a soft, wearable device designed to provide continuous assistance at the hip and knee joint when working with and against gravity in ADLs. This robotic device combines active and passive elements with a closed-loop force controller designed to behave like an external muscle (exomuscle) and deliver gravity compensation to the user. At 4.1 kg (4.6 kg with batteries), the Myosuit is one of the lightest untethered devices capable of delivering gravity support to the user's knee and hip joints. This article presents the design and control principles of the Myosuit. It describes the textile interface, tendon actuators, and a bi-articular, synergy-based approach for continuous assistance. The assistive controller, based on bi-articular force assistance, was tested with a single subject who performed sitting transfers, one of the most gravity-intensive ADLs. The results show that the control concept can successfully identify changes in the posture and assist hip and knee extension with up to 26% of the natural knee moment and up to 35% of the knee power. We conclude that the Myosuit's novel approach to assistance using a bi-articular architecture, in combination with the posture-based force controller, can effectively assist its users in gravity-intensive ADLs, such as sitting transfers.