An 88-milligram insect-scale autonomous crawling robot driven by a catalytic artificial muscle.

The creation of autonomous subgram microrobots capable of complex behaviors remains a grand challenge in robotics largely due to the lack of microactuators with high work densities and capable of using power sources with specific energies comparable to that of animal fat (38 megajoules per kilogram). Presently, the vast majority of microrobots are driven by electrically powered actuators; consequently, because of the low specific energies of batteries at small scales (below 1.8 megajoules per kilogram), almost all the subgram mobile robots capable of sustained operation remain tethered to external power sources through cables or electromagnetic fields.

An earthworm-inspired soft robot with perceptive artificial skin.

The bodies of earthworms are composed of repeating deformable structural units, called metameres, that generate the peristaltic body motions required for limbless underground burrowing and above-ground crawling. Metameres are actuated by circular and longitudinal muscles that are activated synchronously by the animals' nervous systems. A significant number of the neural-motor feedback loops function with sensory input gathered by the animals' highly sensitive skins, which are embedded with light, pressure and chemical receptors.

An earthworm-inspired friction-controlled soft robot capable of bidirectional locomotion.

We present the design, fabrication, modeling and feedback control of an earthworm-inspired soft robot capable of bidirectional locomotion on both horizontal and inclined flat platforms. In this approach, the locomotion patterns are controlled by actively varying the coefficients of friction between the contacting surfaces of the robot and the supporting platform, thus emulating the limbless locomotion of earthworms at a conceptual level. Earthworms are characterized by segmented body structures, known as metameres, composed of longitudinal and circular muscles which during locomotion are contracted and relaxed periodically in order to generate a peristaltic wave that propagates backwards with respect to the worm's traveling direction; simultaneously, microscopic bristle-like structures (setae) on each metamere coordinately protrude or retract to provide varying traction with the ground, thus enabling the worm to burrow or crawl.

Thermosensitive in situ hydrogel based on the hybrid of hyaluronic acid and modified PCL/PEG triblock copolymer.

In this work, a new hydrogel was constructed using poly(ɛ-caprolactone-co-1,4,8-trioxa[4.6]spiro-9-undecanone)-poly(ethylene glycol)-poly(ɛ-caprolactone-co-1,4,8-trioxa[4.6]spiro-9-undecanone) tri-block copolymers (PECT) with hyaluronic acid (HA) in order to expand application scopes of PECT hydrogel.

Photo-crosslinked poly(ethylene glycol)-b-poly(ϵ-caprolactone) nanoparticles for controllable paclitaxel release.

Novel biodegradable core-crosslinked nanoparticles (CNPs) consisting of methoxy poly(ethylene glycol)-block-poly(ϵ-caprolactone-co-γ-cinnamoyloxy-ϵ-caprolactone) (mPEG-b-P(CL-co-CCL)) were prepared and evaluated for paclitaxel (PTX) delivery. mPEG113-b-P(CL65.2-co-CCL10.

Poly(ethyleneglycol)-b-poly(ε-caprolactone-co-γ-hydroxyl-ε- caprolactone) bearing pendant hydroxyl groups as nanocarriers for doxorubicin delivery.

A novel biodegradable amphiphilic diblock copolymer methoxy poly(ethylene glycol)-b-poly(ε-caprolactone-co-γ-hydroxyl-ε-caprolactone) (mPEG-b-P(CL-co-HCL)) bearing pendant hydroxyl groups on the PCL block was prepared. The hydroxyl groups were formed through the reduction of ketones by sodium borohydride without protection and deprotection. The obtained polymers were well characterized by (1)H NMR, Fourier transform infrared (FT-IR), gel permeation chromatography (GPC), differential scanning calorimetry (DSC), X-ray diffraction (XRD), and contact angle measurement.