scholarly journals Thermo-Responsive Hydrogel-Based Soft Valves with Annular Actuation Calibration and Circumferential Gripping

2021 ◽  
Vol 8 (9) ◽  
pp. 127
Author(s):  
Manivannan Sivaperuman Kalairaj ◽  
Hritwick Banerjee ◽  
Kirthika Senthil Kumar ◽  
Keith Gerard Lopez ◽  
Hongliang Ren

Valves are largely useful for treatment assistance devices, e.g., supporting fluid circulation movement in the human body. However, the valves presently used in biomedical applications still use materials that are rigid, non-compliant, and hard to integrate with human tissues. Here, we propose biologically-inspired, stimuli-responsive valves and evaluate N-Isopropylacrylamide hydrogels-based valve (NPHV) and PAAm-alginate hydrogels-based valve (PAHV) performances with different chemical syntheses for optimizing better valve action. Once heated at 40 ∘C, the NPHV outperforms the PAHV in annular actuation (NPHV: 1.93 mm displacement in 4 min; PAHV: 0.8 mm displacement in 30 min). In contrast, the PAHV exhibits a flow rate change of up to 20%, and a payload of 100% when the object is at 100 ∘C. The PAHV demonstrated a completely soft, stretchable circular gripper with a high load-to-weight ratio for diversified applications. These valves are fabricated with a simple one-pot method that, once further optimized, can offer transdisciplinary applications.

2021 ◽  
Author(s):  
Aroa Duro-Castano ◽  
Laura Rodriguez-Arco ◽  
Lorena Ruiz-Perez ◽  
Cesare De Pace ◽  
Gabriele Marchello ◽  
...  

Polypeptide-based nanoparticles offer unique advantages from a nanomedicine perspective such as biocompatibility, biodegradability and stimuli-responsive properties to (patho)physiological conditions. Conventionally, self-assembled polypeptide nanostructures are prepared by first synthesizing their constituent amphiphilic polypeptides followed by post-polymerization self-assembly. Herein, we describe the one-pot synthesis of oxidation-sensitive supramolecular micelles and vesicles. This was achieved by polymerization-induced self-assembly (PISA) of the N-carboxyanhydride (NCA) precursor of methionine using polyethylene oxide as stabilizing and hydrophilic block in dimethyl sulfoxide (DMSO). By adjusting the hydrophobic block length and concentration we obtained a range of morphologies from spherical to worm-like micelles, to vesicles. Remarkably, the secondary structure of polypeptides greatly influenced the final morphology of the assemblies. Surprisingly, worm-like micellar morphologies were obtained for a wide range of methionine block lengths and solid contents, with spherical micelles restricted to very short hydrophobic lengths. Worm-like micelles further assembled into oxidation-sensitive, self-standing gels in the reaction pot. Both vesicles and worm-like micelles obtained using this method demonstrated to degrade under controlled oxidant conditions which would expand their biomedical applications such as in sustained drug release or as cellular scaffolds in tissue engineering.


Author(s):  
Jinzhu Huang ◽  
Xiaoyuan Zhang ◽  
Kun Fu ◽  
Gang Wei ◽  
Zhiqiang Su

Cancer is a growing threat to human beings. Traditional treatments for malignant tumors usually involve invasive means to healthy human tissues, such as surgical treatment and chemotherapy. In recent years...


2021 ◽  
Vol 62 (8) ◽  
Author(s):  
Lionel Hirschberg ◽  
Friedrich Bake ◽  
Karsten Knobloch ◽  
Angelo Rudolphi ◽  
Sebastian Kruck ◽  
...  

AbstractMeasurements of sound due to swirl–nozzle interaction are presented. In the experiment a swirl structure was generated by means of unsteady tangential injection into a steady swirl-free flow upstream from a choked convergent–divergent nozzle. Ingestion of swirl by the choked nozzle caused a mass-flow rate change, which resulted in a downstream-measured acoustic response. The downstream acoustic pressure was found to remain negative as long as the swirl is maintained and reflections from the open downstream pipe termination do not interfere. The amplitude of this initial acoustic response was found to be proportional to the square of the tangential mass-flow rate used to generate swirl. When the tangential injection valve was closed, the mass-flow rate through the nozzle increased, resulting in an increase of the downstream acoustic pressure. This increase in signal was compared to the prediction of an empirical quasi-steady model, constructed from steady-state flow measurements. As the opening time of the valve was varied, the signal due to swirl evacuation showed an initial overshoot with respect to quasi-steady behavior, after which it gradually decayed to quasi-steady behavior for tangential injection times long compared to the convection time in the pipe upstream of the nozzle. This demonstrates that the acoustic signal can be used to obtain quantitative information concerning the time dependence of the swirl in the system. This could be useful for understanding the dynamics of flow in engines with swirl-stabilized combustion. Graphic abstract


2019 ◽  
Vol 6 (1) ◽  
pp. 160-168 ◽  
Author(s):  
Yajuan Sun ◽  
Linfeng Chen ◽  
Yan Jiang ◽  
Xuan Zhang ◽  
Xiukai Yao ◽  
...  

A general class of stimuli-responsive grippers and actuators (e.g., temperature- and pH-responsive) with surprisingly high gripping strengths is introduced.


Author(s):  
Ranhua Xiong ◽  
Ronald X. Xu ◽  
Chaobo Huang ◽  
Stefaan De Smedt ◽  
Kevin Braeckmans

This review presents an overview of the recent advances in the development of stimuli-responsive nanobubbles and their novel biomedical applications including bio-imaging, drug delivery and ablation of tumor tissues.


Langmuir ◽  
2013 ◽  
Vol 29 (34) ◽  
pp. 10850-10858 ◽  
Author(s):  
Vinith Yathindranath ◽  
Zhizhi Sun ◽  
Matthew Worden ◽  
Lynda J. Donald ◽  
James A. Thliveris ◽  
...  

2022 ◽  
Vol 23 (2) ◽  
pp. 610
Author(s):  
Teresa Aditya ◽  
Jean Paul Allain ◽  
Camilo Jaramillo ◽  
Andrea Mesa Restrepo

Bacterial cellulose is a naturally occurring polysaccharide with numerous biomedical applications that range from drug delivery platforms to tissue engineering strategies. BC possesses remarkable biocompatibility, microstructure, and mechanical properties that resemble native human tissues, making it suitable for the replacement of damaged or injured tissues. In this review, we will discuss the structure and mechanical properties of the BC and summarize the techniques used to characterize these properties. We will also discuss the functionalization of BC to yield nanocomposites and the surface modification of BC by plasma and irradiation-based methods to fabricate materials with improved functionalities such as bactericidal capabilities.


2021 ◽  
Vol 9 ◽  
Author(s):  
Udisha Singh ◽  
Vinod Morya ◽  
Bhaskar Datta ◽  
Chinmay Ghoroi ◽  
Dhiraj Bhatia

Of the multiple areas of applications of DNA nanotechnology, stimuli-responsive nanodevices have emerged as an elite branch of research owing to the advantages of molecular programmability of DNA structures and stimuli-responsiveness of motifs and DNA itself. These classes of devices present multiples areas to explore for basic and applied science using dynamic DNA nanotechnology. Herein, we take the stake in the recent progress of this fast-growing sub-area of DNA nanotechnology. We discuss different stimuli, motifs, scaffolds, and mechanisms of stimuli-responsive behaviours of DNA nanodevices with appropriate examples. Similarly, we present a multitude of biological applications that have been explored using DNA nanodevices, such as biosensing, in vivo pH-mapping, drug delivery, and therapy. We conclude by discussing the challenges and opportunities as well as future prospects of this emerging research area within DNA nanotechnology.


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