scholarly journals Cation-induced shape programming and morphing in protein-based hydrogels

2020 ◽  
Vol 6 (18) ◽  
pp. eaba6112
Author(s):  
Luai R. Khoury ◽  
Marina Slawinski ◽  
Daniel R. Collison ◽  
Ionel Popa
Keyword(s):  
Serum Albumin ◽  
Smart Materials ◽  
Room Temperature ◽  
Marked Change ◽  
Innovative Strategy ◽  
Innovative Method ◽  
Ring Shape ◽  
Shape Programming ◽  
And Robotics ◽  
Shape Changes

Smart materials that are capable of memorizing a temporary shape, and morph in response to a stimulus, have the potential to revolutionize medicine and robotics. Here, we introduce an innovative method to program protein hydrogels and to induce shape changes in aqueous solutions at room temperature. We demonstrate our approach using hydrogels made from serum albumin, the most abundant protein in the blood plasma, which are synthesized in a cylindrical or flower shape. These gels are then programmed into a spring or a ring shape, respectively. The programming is performed through a marked change in stiffness (of up to 17-fold), induced by adsorption of Zn2+ or Cu2+ cations. We show that these programmed biomaterials can then morph back into their original shape, as the cations diffuse outside the hydrogel material. The approach demonstrated here represents an innovative strategy to program protein-based hydrogels to behave as actuators.

Vibrational Spectroscopic Analysis of Ferroelectric Liquid Crystal MBOPDOB

1998 ◽  
Vol 52 (6) ◽  
pp. 847-850 ◽  
Author(s):  
Lei He ◽  
Zhen Yin ◽  
Ming-Sheng Zhang ◽  
Ze-Xiang Shen ◽  
Hui-Fen Chen
Keyword(s):  
Liquid Crystal ◽  
Room Temperature ◽  
Spectroscopic Analysis ◽  
Ester Group ◽  
Phase Transition Point ◽  
Vibrational Modes ◽  
Ferroelectric Liquid Crystal ◽  
Temperature Dependent ◽  
Vibrational Characteristics ◽  
Shape Changes

Raman spectra of ferroelectric liquid crystal (FLC) D-4-(2-methylbutoxy) phenyl 4-decyloxybenzoate (MBOPDOB) are recorded. All the vibrational modes are assigned, and their vibrational characteristics are studied. It is found that the s-cis and the s-trans conformers of the ester group coexist in the crystal phase at room temperature. By temperature-dependent measurements, the line shape changes due to the transition of the ester group conformation near the crystal-Sm C phase transition point are examined.

Room Temperature Magnetic-Semicondcutors in Modified Iron Titanates: Their Properties and Potential Microelectronic Devices

2008 ◽  
Vol 54 ◽  
pp. 216-222 ◽  
Author(s):  
R.K. Pandey ◽  
H. Stern ◽  
W.J. Geerts ◽  
P. Padmini ◽  
P. Kale ◽  
...  
Keyword(s):  
Smart Materials ◽  
Room Temperature ◽  
Magnetic Semiconductors ◽  
Novel Technologies ◽  
Microelectronic Devices ◽  
Magnetic Switching ◽  
Current Voltage ◽  
Bandgap Semiconductors ◽  
Multifunctional Oxides ◽  
Mn Doped

The phenomenal growths of information technology and related fields have warranted the development of new class of materials. Multifunctional oxides, magnetic-semiconductors, multiferroics and smart materials are just a few examples of such materials. They are needed for the development of novel technologies such as spintronics, magneto-electronics, radhard electronics, and advanced microelectronics. For these technologies, of particular interest are some solid solutions of ilmenite-hematite (IH) represented by (1-x) FeTiO3.xFe2O3 where x varies from 0 to 1; Mn-doped ilmenite (Mn+3-FeTiO3) and Mn-doped pseudobrookite, Mn+3-Fe2TiO5 (PsB). These multifunctional oxides are ferromagnetic with the magnetic Curie points well above the room temperature as well as wide bandgap semiconductors with band gap Eg > 2.5 eV. This paper outlines: (a) processing of device quality samples for structural, electrical and magnetic characterization, (b) fabrication and evaluation of an integrated structure for controlled magnetic switching, and (c) the response of the two terminal non-linear current-voltage (I-V) characteristics when biased by a dc voltage. Subsequently, we will identify a few microelectronic applications based on this class of oxides.

Influence of Blocking Agents on Non-Specific Background of Polystyrene Microbeads in Serum Immunoassay

2013 ◽  
Vol 641-642 ◽  
pp. 858-861 ◽  
Author(s):  
Zhi Min Ren ◽  
Xi Nie ◽  
Sheng Shu Ai
Keyword(s):  
Bovine Serum Albumin ◽  
Polyvinyl Alcohol ◽  
Serum Albumin ◽  
Human Serum ◽  
Phosphate Buffer ◽  
Bovine Serum ◽  
Room Temperature ◽  
Tween 20 ◽  
Blocking Agents

In this paper, we used bovine serum albumin and polymer as the blocking agents and investigated the effect of blocking agents on non-specific background of polystyrene microbead that used the human serum immunoassay.The results showed that the nonspecific background is lower by using polymer blocking agents. The best blocking condition was that microbeads were blocked by PVXT (0.5% polyvinyl alcohol PVA, 0.8% polyvinylpyrrolidone, 0.05% Tween-20, PBS phosphate buffer, pH7.0) for two hours at room temperature.

Rapid radioimmunoassay of total urinary estriol.

1976 ◽  
Vol 22 (5) ◽  
pp. 611-615 ◽  
Author(s):  
D W Anderson ◽  
U Goebelsmann
Keyword(s):  
Urinary Tract ◽  
Bovine Serum Albumin ◽  
Serum Albumin ◽  
Ammonium Sulfate ◽  
Bovine Serum ◽  
Room Temperature ◽  
Urine Specimen ◽  
Ammonium Sulfate Precipitation ◽  
In Pregnancy

Abstract We describe a radioimmunoassay for total urinary estriol in pregnancy. A 25-mul aliquot of the urine specimen is acid hydrolyzed, neutralized, and diluted before assay. We use rabbit antisera against estriol-6-(O-carboxymethyl)oxime/bovine serum albumin and ammonium sulfate precipitation at room temperature. Results are unaffected by glucose or methenamine mandelate, a urinary tract antiseptic. Using semi-automatic pipetting equipment, one laboratory technologist can complete 50 assays within 8 h. This technique is both reliable and convenient and should decrease the expense of routine estriol assays.

Design of Linear Actuators Based on Compliant Multi-Stable Structures

2017 ◽  
Author(s):  
Aaron J. Anderson ◽  
Andres F. Arrieta
Keyword(s):  
Smart Materials ◽  
Polymer Materials ◽  
Linear Actuator ◽  
Light Weight ◽  
Stable States ◽  
Stroke Length ◽  
Smart Systems ◽  
Load Carrying ◽  
And Robotics ◽  
Stable Structures

Light-weight, compact actuators capable of delivering large linear stroke based compliant structures offer interesting potential for adaptive structures and robotics given their capability to carry a load and to be geometrically scalable. Furthermore, the utilization of compliant structures replacing mechanisms and moving parts offers the possibility for reducing losses due to friction. Solid state actuators have been proposed as a means to attain such capabilities with particular success for smart systems based on piezoelectric, shape memory, and electroactive polymer materials. Despite this success, smart material systems do not concurrently offer large strokes, high blocking force and wide response bandwidth. Recently, a new class of multi-stable structures that generate large linear strokes from twisting have been introduced. Furthermore, the snap-through action characterizing the changes between stable states of multi-stable systems has been shown to be a viable mechanism for inducing controlled actuation at high rates. In this paper, the novel design of a linear actuator adapted from twisting multi-stable structures is tailored to have geometric instability that is exploited to achieve large axial strokes under the action of small deformations from a single structural component. Finite element modeling is used for analysis of the structure, where parameter studies of composite layup and structure geometry are conducted to adjust equilibrium positions and stroke length of the actuator design. Different smart actuator topologies demonstrating the ability for compliant multi-stable systems are coupled with smart materials to produce large linear deformations and wide actuation bandwidth. The herein presented unconventional design serves as a useful linear actuator, as well as a load carrying component. The introduced multi-functional light-weight load-carrying actuators relevant for aerospace and robotics applications.

Effect of Heat-Treatment on the Phases of Ni-Mn-Ga Magnetic Shape Memory Alloys

2009 ◽  
Vol 152-153 ◽  
pp. 497-500
Author(s):  
Pnina Ari-Gur ◽  
Giora Kimmel ◽  
James W. Richardson ◽  
Ashfia Huq ◽  
Kapil Sharma
Keyword(s):  
Shape Memory ◽  
Smart Materials ◽  
Room Temperature ◽  
Large Strain ◽  
Heusler Alloys ◽  
Stoichiometric Composition ◽  
Processing Parameters ◽  
Crystallographic Investigation ◽  
Magnetic Shape Memory ◽  
Magnetic Shape Memory Alloys

The Heusler alloys Ni50Mn25+xGa25-x display magnetic shape memory effect (MSM) with very fast and large reversible strain under magnetic fields. This large strain and the speed of reaction make MSM alloys attractive as smart materials. Our crystallographic investigation of these alloys, focused on non-stoichiometric composition with excess of manganese. Using neutron diffraction, we revealed the necessary processing parameters to achieve and preserve the homogeneous metastable one-phase martensitic structure that is needed for an MSM effect at room temperature.

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