Fluidic McKibben artificial muscles are one of the most popular biomimetic actuators, showing similar static and dynamic performance to skeletal muscles. In particular, their pneumatic version offers high-generated force, high speed and high strain in comparison to other actuators. This paper investigates the development of a small-size, fully enclosed, hydraulic McKibben muscle powered by a low voltage pump. Hydraulic McKibben muscles with an outside diameter of 6 mm and a length ranging from 35 mm to 80 mm were investigated. These muscles are able to generate forces up to 26 N, strains up to 23%, power to mass of 30 W/kg and tension intensity of 1.78 N/mm 2 at supply water pressure of 2.5 bar. The effects of injected pressure and inner tube stiffness on the actuation strain and force generation were studied and a simple model introduced to quantitatively estimate force and stroke generated for a given input pressure. This unique actuation system is lightweight and can be easily modified to be employed in small robotic systems where large movements in short time are required.  Effect of the bladder stiffness on Muscle performance is studied. A new and more accurate equation to predict the muscle performances is proposed. A sealed actuation system suitable for robotic machines with low voltage water pump is introduced. AbstractFluidic McKibben artificial muscles are one of the most popular biomimetic actuators, showing similar static and dynamic performance to skeletal muscles. In particular, their pneumatic version offers high-generated force, high speed and high strain in comparison to other actuators. This paper investigates the development of a small-size, fully enclosed, hydraulic McKibben muscle powered by a low voltage pump. Hydraulic McKibben muscles with an outside diameter of 6 mm and a length ranging from 35 mm to 80 mm were investigated. These muscles are able to generate forces up to 26 N, strains up to 23%, power to mass of 30 W/kg and tension intensity of 1.78 N/mm 2 at supply water pressure of 2.5 Bar. The effects of injected pressure and inner tube stiffness on the actuation strain and force generation were studied and a simple model introduced to quantitatively estimate force and stroke generated for a given input pressure. This unique actuation system is lightweight and can be easily modified to be employed in small robotic systems where large movements in short time are required.

Gelatin based hydrogels are often incorporated with supporting materials such as chitosan, poly­(vinyl alcohol), alginate, carbon nanotubes, and hyaluronic acid. These hybrid materials are specifically of interest in diversified nanomedicine fields as they exhibit unique physicochemical properties, antimicrobial activity, biodegradability, and biocompatibility. The applications include drug delivery, wound healing, cell culture, and tissue engineering. This paper reviews the various up-to-date methods to fabricate gelatin-based hydrogels, including UV photo-cross-linking, electrospinning, and 3D bioprinting. This paper also includes physical, chemical, mechanical, and biocompatibility characterization studies of several hybrid gelatin hydrogels and discusses their relevance in nanomedicine based applications. Challenges associated with the fabrication of hybrid materials for nanotechnology implementation, specifically in nanomedicine development, are critically discussed, and some future recommendations are provided.

Layered inorganic solids as an attractive classification of 2D materials offer material diversity and a wide range of interesting properties. Layered inorganic solids provide an expandable 2D nanospace between each individual layer, the so called interlayer space, to accommodate/arrange guest species such as molecules, nanoparticles, and polymer chains and design unique nanoarchitectures, resulting in the production of intercalation compounds showing different properties in comparison to those of virgin layered materials and guest species. Layered inorganic solids can also be exfoliated to result in nanosheet production. Further ordering of exfoliated nanosheets is also possible via different methods and normally leads to creating soft materials presenting properties and applications different from that of relatively rigid intercalation compounds. Here, the latest studies and up-to-date developments on the possible techniques of designing novel types of materials using layered inorganic solids are specifically highlighted.

McKibben artificial muscles are one of the most pragmatic contractile actuators, offering performances similar to skeletal muscles. The McKibben muscles operate by pumping pressurized fluid into a bladder constrained by a stiff braid so that tensile force generated is amplified in comparison to a conventional hydraulic ram. The need for heavy and bulky compressors/ pumps makes pneumatic or hydraulic McKibben muscles unsuitable for microactuators, where a highly compact design is required. In an alternative approach, this article describes a new type of McKibben muscle using an expandable guest fill material, such as temperature-sensitive paraffin, to achieve a more compact and lightweight actuation system. Two different types of paraffin-filled McKibben muscles are introduced and compared. In the first system, the paraffinfilled McKibben muscle is simply immersed in a hot water bath and generates isometric forces up to 850 mN and a free contraction strain of 8.3% at 95C. In the second system, paraffin is heated directly by embedded heating elements and exhibits the maximum isometric force of 2 N and 9% contraction strain. A quantitative model is also developed to predict the actuation performance of these temperature sensitive McKibben muscles as a function of temperature.