scholarly journals Reconfiguring confined magnetic colloids with tunable fluid transport behavior

2020 ◽  
Author(s):  
Zhizhi Sheng ◽  
Mengchuang Zhang ◽  
Jing Liu ◽  
Paolo Malgaretti ◽  
Jianyu Li ◽  
...  

Abstract Collective dynamics of confined colloids is crucial in diverse scenarios such as self-assembly and phase behavior in materials science, microrobot swarms for drug delivery, and microfluidic control. Yet, fine-tuning the dynamics of colloids in microscale confined spaces is still a formidable task due to the complexity of the dynamics of colloidal suspension and to the lack of methodology to probe colloids in confinement. Here, we show that the collective dynamics of confined magnetic colloids can be finely tuned by external magnetic fields. In particular, the mechanical properties of the confined colloidal suspension can be probed in real-time and this strategy can be also used to tune microscale fluid transport. Our experimental and theoretical investigations reveal that the collective configuration characterized by the colloidal entropy is controlled by the colloidal concentration, confining ratio, and external field strength and direction. Indeed, our results show that mechanical properties of the colloidal suspension as well as the transport of the solvent in microfluidic devices can be controlled upon tuning the entropy of the colloidal suspension. Our approach opens new avenues for the design and applications of drug delivery, microfluidic logic, dynamic fluid control, chemical reaction, and beyond.

2019 ◽  
Author(s):  
Mark Workentin ◽  
François Lagugné-Labarthet ◽  
Sidney Legge

In this work we present a clean one-step process for modifying headgroups of self-assembled monolayers (SAMs) on gold using photo-enabled click chemistry. A thiolated, cyclopropenone-caged strained alkyne precursor was first functionalized onto a flat gold substrate through self-assembly. Exposure of the cyclopropenone SAM to UV-A light initiated the efficient photochemical decarbonylation of the cyclopropenone moiety, revealing the strained alkyne capable of undergoing the interfacial strain-promoted alkyne-azide cycloaddition (SPAAC). Irradiated SAMs were derivatized with a series of model azides with varied hydrophobicity to demonstrate the generality of this chemical system for the modification and fine-tuning of the surface chemistry on gold substrates. SAMs were characterized at each step with polarization-modulation infrared reflection-absorption spectroscopy (PM-IRRAS) to confirm successful functionalization and reactivity. Furthermore, to showcase the compatibility of this approach with biochemical applications, cyclopropenone SAMs were irradiated and modified with azide-bearing cell adhesion peptides to promote human fibroblast cell adhesion, then imaged by live cell fluorescence microscopy. Thus, the “photoclick” methodology reported here represents an improved, versatile, catalyst-free protocol that allows for a high degree of control over the modification of material surfaces, with applicability in materials science as well as biochemistry.<br>


2019 ◽  
Author(s):  
Mark Workentin ◽  
François Lagugné-Labarthet ◽  
Sidney Legge

In this work we present a clean one-step process for modifying headgroups of self-assembled monolayers (SAMs) on gold using photo-enabled click chemistry. A thiolated, cyclopropenone-caged strained alkyne precursor was first functionalized onto a flat gold substrate through self-assembly. Exposure of the cyclopropenone SAM to UV-A light initiated the efficient photochemical decarbonylation of the cyclopropenone moiety, revealing the strained alkyne capable of undergoing the interfacial strain-promoted alkyne-azide cycloaddition (SPAAC). Irradiated SAMs were derivatized with a series of model azides with varied hydrophobicity to demonstrate the generality of this chemical system for the modification and fine-tuning of the surface chemistry on gold substrates. SAMs were characterized at each step with polarization-modulation infrared reflection-absorption spectroscopy (PM-IRRAS) to confirm successful functionalization and reactivity. Furthermore, to showcase the compatibility of this approach with biochemical applications, cyclopropenone SAMs were irradiated and modified with azide-bearing cell adhesion peptides to promote human fibroblast cell adhesion, then imaged by live cell fluorescence microscopy. Thus, the “photoclick” methodology reported here represents an improved, versatile, catalyst-free protocol that allows for a high degree of control over the modification of material surfaces, with applicability in materials science as well as biochemistry.<br>


Polymers ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 2872
Author(s):  
Alberto Concellón ◽  
María San Anselmo ◽  
Silvia Hernández-Ainsa ◽  
Pilar Romero ◽  
Mercedes Marcos ◽  
...  

The design of efficient drug-delivery vehicles remains a big challenge in materials science. Herein, we describe a novel class of amphiphilic hybrid dendrimers that consist of a poly(amidoamine) (PAMAM) dendritic core functionalized with bisMPA dendrons bearing cholesterol and coumarin moieties. Their self-assembly behavior both in bulk and in water was investigated. All dendrimers exhibited smectic A or hexagonal columnar liquid crystal organizations, depending on the generation of the dendrimer. In water, these dendrimers self-assembled to form stable spherical micelles that could encapsulate Nile Red, a hydrophobic model compound. The cell viability in vitro of the micelles was studied in HeLa cell line, and proved to be non-toxic up to 72 h of incubation. Therefore, these spherical micelles allow the encapsulation of hydrophobic molecules, and at the same time provided fluorescent traceability due to the presence of coumarin units in their chemical structure, demonstrating the potential of these dendrimers as nanocarriers for drug-delivery applications.


2018 ◽  
Vol 6 (1) ◽  
pp. 216-224 ◽  
Author(s):  
Yi-An Lin ◽  
Myungshim Kang ◽  
Wei-Chiang Chen ◽  
Yu-Chuan Ou ◽  
Andrew G. Cheetham ◽  
...  

Supramolecular filament hydrogels are an emerging class of biomaterials that hold great promise for regenerative medicine, tissue engineering, and drug delivery. The use of isomeric hydrocarbons in the peptide design enables fine-tuning of the mechanical properties of their supramolecular filament hydrogels without altering their network structures.


2018 ◽  
Vol 4 (4) ◽  
pp. 514-518 ◽  
Author(s):  
Dishari Dutta ◽  
Chowdhury Mobaswar Hossain ◽  
Avijit Biswas

Primarily Silk is classified as Mulberry silk (collected from Bombyx mori) and Non-Mulberry silk (collected from sources other than Bombyx mori). Whilst Mulberry silk has gained its importance in biomedical application due to superior biocompatibility and biodegradable properties when compared to synthetic protologues; such edge cutting popularity is quite new among Non-Mulberry variant. Silk proteins namely Sericin and Fibroin, are reported to have been employed in tissue engineering and drug delivery owing to its biocompatibility, slow biodegradability, self-assembly, excellent mechanical properties and controllable structure and morphology. Silk is less inflammatory than other common biodegradable polymers. Fibroin is the fibre used in textile and biomedical devices whereas Sericin is glue like material which binds the fibres together. The fibroin is further divided into two, based on the molecular weights of chains of amino acid. Sericin, being the glue-like material and constitute the part of silk which was generally washed away during extraction of fibroin used as textile material. Researchers have reported that Sericin do not produce immunogenic responses unless associated with fibroin. The review focuses on silk proteins and its utility in drug delivery.


Gels ◽  
2021 ◽  
Vol 7 (3) ◽  
pp. 134
Author(s):  
Jonathan Bietsch ◽  
Mary Olson ◽  
Guijun Wang

Carbohydrate-based low molecular weight gelators (LMWGs) exhibit many desirable properties making them useful in various fields including applications as drug delivery carriers. In order to further understand the structural connection to gelation properties, especially the influence of halide substitutions, we have designed and synthesized a series of para-chlorobenzylidene acetal protected D-glucosamine amide derivatives. Fifteen different amides were synthesized, and their self-assembling properties were assessed in multiple organic solvents, as well as mixtures of organic solvents with water. All derivatives were found to be gelators for at least one solvent and majority formed gels in multiple solvents at concentrations lower than 2 wt%. A few derivatives rendered remarkably stable gels in aqueous solutions at concentrations below 0.1 wt%. The benzamide 13 formed gels in water and in EtOH/H2O (v/v 1:2) at 0.36 mg/mL. The gels were characterized using optical microscopy and atomic force microscopy, and the self-assembly mechanism was probed using variable temperature 1H-NMR spectroscopy. Gel extrusion studies using H2O/DMSO gels successfully printed lines of gels on glass slides, which retained viscoelasticity based on rheology. Gels formed by the benzamide 13 were used for encapsulation and the controlled release of chloramphenicol and naproxen, as well as for dye removal for toluidine blue aqueous solutions.


Author(s):  
Prashant Malik ◽  
Neha Gulati ◽  
Raj Kaur Malik ◽  
Upendra Nagaich

Nanotechnology deal with the particle size in nanometers. Nanotechnology is ranging from extensions of conventional device physics to completely new approaches based upon molecular self assembly, from developing new materials with dimensions on the nanoscale to direct control of matter on the atomic scale. In nanotechnology mainly three types of nanodevices are described: carbon nanotubes, quantum dots and dendrimers. It is a recent technique used as small size particles to treat many diseases like cancer, gene therapy and used as diagnostics. Nanotechnology used to formulate targeted, controlled and sustained drug delivery systems. Pharmaceutical nanotechnology embraces applications of nanoscience to pharmacy as nanomaterials and as devices like drug delivery, diagnostic, imaging and biosensor materials. Pharmaceutical nanotechnology has provided more fine tuned diagnosis and focused treatment of disease at a molecular level.    


2013 ◽  
Vol 21 (2) ◽  
pp. 194-199
Author(s):  
Zhaoxu Tu ◽  
Xianghui Xu ◽  
Yeting Jian ◽  
Dan Zhong ◽  
Bin He ◽  
...  
Keyword(s):  

2018 ◽  
Vol 24 (8) ◽  
pp. 843-854 ◽  
Author(s):  
Weiguo Xu ◽  
Shujun Dong ◽  
Yuping Han ◽  
Shuqiang Li ◽  
Yang Liu

Hydrogels, as a class of materials for tissue engineering and drug delivery, have high water content and solid-like mechanical properties. Currently, hydrogels with an antibacterial function are a research hotspot in biomedical field. Many advanced antibacterial hydrogels have been developed, each possessing unique qualities, namely high water swellability, high oxygen permeability, improved biocompatibility, ease of loading and releasing drugs and structural diversity. In this article, an overview is provided on the preparation and applications of various antibacterial hydrogels. Furthermore, the prospects in biomedical researches and clinical applications are predicted.


2017 ◽  
Vol 17 (16) ◽  
pp. 1829-1842 ◽  
Author(s):  
Zhiyong Zhao ◽  
Feng Liang ◽  
Simin Liu

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