Curved Origami-Based Mechanical Metamaterials with Selectable Creases for In-Situ Tunable Stiffness

2020 ◽  
Author(s):  
Hanqing Jiang
Keyword(s):  
Mechanical Metamaterials ◽  
Tunable Stiffness

A Facile Strategy for In Situ Controlled Delivery of Doxorubicin with a pH-Sensitive Injectable Hydrogel

Nano LIFE ◽  
2014 ◽  
Vol 04 (03) ◽  
pp. 1441001 ◽  
Author(s):  
Jun Chen ◽  
Xiaojian Li ◽  
Liqian Gao ◽  
Yi Hu ◽  
Wen Zhong ◽  
...  
Keyword(s):  
Ph Sensitive ◽  
Controlled Delivery ◽  
Cell Uptake ◽  
Injectable Hydrogel ◽  
Poorly Soluble ◽  
Poly Ethylene ◽  
Novel Strategy ◽  
Ph Sensitive Polymer ◽  
Tunable Stiffness

In light of the challenges along with the traditional intravenous administration of chemotherapeutics, injectable hydrogel-drug system emerges as a powerful tool for noninvasive and in situ controlled-release of drugs. Herein, we report a novel strategy of drug delivery system with pH responsive injectable hydrogels by taking advantages of two biomaterials. The first one is a pH sensitive polymer-drug (prodrug) conjugate, poly (ethylene glycol)–doxorubicin (MPEG–DOX) with hydrazone linkage. This prodrug interacted with a second biomaterial, α-cyclodextrin (α-CD) under mild conditions and subsequently formed the hydrogels in minutes with tunable stiffness. The gels showed a sustained release behavior dependent on the surrounding pH and released drugs effectively killed tumor cells (MCF-7). The quick cell uptake and efficient intracellular delivery of DOX were observed under a confocal microscope. This study thus provides a novel and simple drug encapsulation strategy to deliver poorly soluble drugs in situ for a potential targeted chemotherapy.

scholarly journals Origami-inspired, on-demand deployable and collapsible mechanical metamaterials with tunable stiffness

2018 ◽  
Vol 115 (9) ◽  
pp. 2032-2037 ◽  
Author(s):  
Zirui Zhai ◽  
Yong Wang ◽  
Hanqing Jiang
Keyword(s):  
Energy Analysis ◽  
Small Perturbations ◽  
Load Bearing ◽  
On Demand ◽  
High Stiffness ◽  
Mechanical Metamaterials ◽  
Low Stiffness ◽  
Tunable Stiffness

Origami has been employed to build deployable mechanical metamaterials through folding and unfolding along the crease lines. Deployable metamaterials are usually flexible, particularly along their deploying and collapsing directions, which unfortunately in many cases leads to an unstable deployed state, i.e., small perturbations may collapse the structure along the same deployment path. Here we create an origami-inspired mechanical metamaterial with on-demand deployability and selective collapsibility through energy analysis. This metamaterial has autonomous deployability from the collapsed state and can be selectively collapsed along two different paths, embodying low stiffness for one path and substantially high stiffness for another path. The created mechanical metamaterial yields load-bearing capability in the deployed direction while possessing great deployability and collapsibility. The principle in this work can be utilized to design and create versatile origami-inspired mechanical metamaterials that can find many applications.

In-situ tunable auxeticity in pressurized soft mechanical metamaterials

2020 ◽  
Author(s):  
Narayanan Kidambi ◽  
Vipin Agarwal ◽  
Tyler N. Tallman ◽  
Kon-Well Wang
Keyword(s):  
Mechanical Metamaterials

Rendez vous with Saturn's rings

1984 ◽  
Vol 75 ◽  
pp. 743-759 ◽  
Author(s):  
Kerry T. Nock
Keyword(s):  
Solar Energy ◽  
Electric Propulsion ◽  
Power Source ◽  
Propulsion System ◽  
Low Thrust ◽  
Ring Plane ◽  
The Earth ◽  
Total Impulse ◽  
Saturn's Rings

ABSTRACTA mission to rendezvous with the rings of Saturn is studied with regard to science rationale and instrumentation and engineering feasibility and design. Future detailedin situexploration of the rings of Saturn will require spacecraft systems with enormous propulsive capability. NASA is currently studying the critical technologies for just such a system, called Nuclear Electric Propulsion (NEP). Electric propulsion is the only technology which can effectively provide the required total impulse for this demanding mission. Furthermore, the power source must be nuclear because the solar energy reaching Saturn is only 1% of that at the Earth. An important aspect of this mission is the ability of the low thrust propulsion system to continuously boost the spacecraft above the ring plane as it spirals in toward Saturn, thus enabling scientific measurements of ring particles from only a few kilometers.

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