scholarly journals Hydrogels: A Novel Drug Delivery System

2020 ◽  
Vol 1 (8) ◽  
pp. 439-451
Author(s):  
Tayyaba Rana ◽  
Madeeha Fatima ◽  
Abdul Qayyum Khan ◽  
Zainab Naeem ◽  
Sumiyya Javaid ◽  
...  
Keyword(s):  
Skin Diseases ◽  
Three Dimensional ◽  
Biological Molecules ◽  
Extensive Literature ◽  
Swelling Capacity ◽  
Hydrogel Synthesis ◽  
Sanitary Products ◽  
Ionic Bonds ◽  
Cross Links ◽  
Novel Drug

Hydrogels are water-swollen networks, which are cross-linked structures consisting of hydrophilic polymers. They are made three-dimensional by the creation of the cross-links by joining them through covalent or ionic bonds. Hydrogels have been used in various areas including industry and medicine due to their excellent characteristics such as high swelling capacity, high content of water, compatibility with other biological molecules, controlled chemical and physical properties, high mechanical integrity and biodegradability. They have been the center of attention of researchers from the past 50 years because of their promising applications in industries and other areas. They are used in different fields, in medicine, in the diagnosis of the diseases, in culturing of cells, in injuries as wound healers, in cosmetics, in skin diseases like pruritis, in environmental pollution reduction and other miscellaneous applications such as in diapers for babies and sanitary products. Extensive literature can be found on the subject of hydrogels. The present review discusses the history, description of hydrogels, basic properties, classification, different techniques or methods of hydrogel synthesis and the areas in which hydrogels find applications.

scholarly journals Bioprinting Scaffolds for Vascular Tissues and Tissue Vascularization

2021 ◽  
Vol 8 (11) ◽  
pp. 178
Author(s):  
Peter Viktor Hauser ◽  
Hsiao-Min Chang ◽  
Masaki Nishikawa ◽  
Hiroshi Kimura ◽  
Norimoto Yanagawa ◽  
...  
Keyword(s):  
3D Printing ◽  
Large Scale ◽  
Three Dimensional ◽  
Biological Properties ◽  
Biological Molecules ◽  
Future Directions ◽  
Artificial Tissue ◽  
Hydrogel Synthesis ◽  
Cell Sources ◽  
Hybrid Scaffolds

In recent years, tissue engineering has achieved significant advancements towards the repair of damaged tissues. Until this day, the vascularization of engineered tissues remains a challenge to the development of large-scale artificial tissue. Recent breakthroughs in biomaterials and three-dimensional (3D) printing have made it possible to manipulate two or more biomaterials with complementary mechanical and/or biological properties to create hybrid scaffolds that imitate natural tissues. Hydrogels have become essential biomaterials due to their tissue-like physical properties and their ability to include living cells and/or biological molecules. Furthermore, 3D printing, such as dispensing-based bioprinting, has progressed to the point where it can now be utilized to construct hybrid scaffolds with intricate structures. Current bioprinting approaches are still challenged by the need for the necessary biomimetic nano-resolution in combination with bioactive spatiotemporal signals. Moreover, the intricacies of multi-material bioprinting and hydrogel synthesis also pose a challenge to the construction of hybrid scaffolds. This manuscript presents a brief review of scaffold bioprinting to create vascularized tissues, covering the key features of vascular systems, scaffold-based bioprinting methods, and the materials and cell sources used. We will also present examples and discuss current limitations and potential future directions of the technology.

3-D reconstruction of molecular shape from microcrystal thin sections

1983 ◽  
Vol 41 ◽  
pp. 748-749
Author(s):  
S. Cusack ◽  
J.-C. Jésior
Keyword(s):  
Three Dimensional ◽  
Molecular Shape ◽  
Biological Molecules ◽  
Fourier Space ◽  
Single Particles ◽  
Thin Sections ◽  
Standard Methods ◽  
X Ray ◽  
X Ray Crystallography ◽  
Dimensional Reconstruction

Three-dimensional reconstruction techniques using electron microscopy have been principally developed for application to 2-D arrays (i.e. monolayers) of biological molecules and symmetrical single particles (e.g. helical viruses). However many biological molecules that crystallise form multilayered microcrystals which are unsuitable for study by either the standard methods of 3-D reconstruction or, because of their size, by X-ray crystallography. The grid sectioning technique enables a number of different projections of such microcrystals to be obtained in well defined directions (e.g. parallel to crystal axes) and poses the problem of how best these projections can be used to reconstruct the packing and shape of the molecules forming the microcrystal.Given sufficient projections there may be enough information to do a crystallographic reconstruction in Fourier space. We however have considered the situation where only a limited number of projections are available, as for example in the case of catalase platelets where three orthogonal and two diagonal projections have been obtained (Fig. 1).

An Update on Recent Advances in Cubosome: A Novel Drug Delivery System

2021 ◽  
Vol 21 ◽  
Author(s):  
Madhukar Garg ◽  
Anju Goyal ◽  
Sapna Kumari
Keyword(s):  
Drug Delivery ◽  
Drug Delivery System ◽  
Lipid Bilayers ◽  
Delivery System ◽  
Liquid Crystalline ◽  
Three Dimensional ◽  
Biologically Active ◽  
Potential Applications ◽  
Health Related ◽  
Novel Drug

: Cubosomes are highly stable nanostructured liquid crystalline dosage delivery form derived from amphiphilic lipids and polymer-based stabilizers converting it in a form of effective biocompatible carrier for the drug delivery. The delivery form comprised of bicontinuous lipid bilayers arranged in three dimensional honeycombs like structure provided with two internal aqueous channels for incorporation of number of biologically active ingredients. In contrast liposomes they provide large surface area for incorporation of different types of ingredients. Due to the distinct advantages of biocompatibility and thermodynamic stability, cubosomes have remained the first preference as method of choice in the sustained release, controlled release and targeted release dosage forms as new drug delivery system for the better release of the drugs. As lot of advancement in the new form of dosage form has bring the novel avenues in drug delivery mechanisms so it was matter of worth to compile the latest updates on the various aspects of mentioned therapeutic delivery system including its structure, routes of applications along with the potential applications to encapsulate variety drugs to serve health related benefits.

scholarly journals Protease-dependent versus -independent cancer cell invasion programs: three-dimensional amoeboid movement revisited

2009 ◽  
Vol 185 (1) ◽  
pp. 11-19 ◽  
Author(s):  
Farideh Sabeh ◽  
Ryoko Shimizu-Hirota ◽  
Stephen J. Weiss
Keyword(s):  
Cancer Cells ◽  
Type I Collagen ◽  
Three Dimensional ◽  
Amoeboid Movement ◽  
Type I ◽  
Collagen Network ◽  
Normal Tissues ◽  
Tissue Invasion ◽  
Absolute Requirement ◽  
Cross Links

Tissue invasion during metastasis requires cancer cells to negotiate a stromal environment dominated by cross-linked networks of type I collagen. Although cancer cells are known to use proteinases to sever collagen networks and thus ease their passage through these barriers, migration across extracellular matrices has also been reported to occur by protease-independent mechanisms, whereby cells squeeze through collagen-lined pores by adopting an ameboid phenotype. We investigate these alternate models of motility here and demonstrate that cancer cells have an absolute requirement for the membrane-anchored metalloproteinase MT1-MMP for invasion, and that protease-independent mechanisms of cell migration are only plausible when the collagen network is devoid of the covalent cross-links that characterize normal tissues.

Die kognitive Legitimität aus Kundensicht im Kontext neuer Unternehmen

2021 ◽  
Author(s):  
Miriam Lohrmann
Keyword(s):  
Literature Review ◽  
Three Dimensional ◽  
Dimensional Structure ◽  
Extensive Literature ◽  
Extensive Literature Review ◽  
New Business ◽  
Potential Customers ◽  
Cognitive Legitimacy

Customer cognitive legitimacy is an important factor in a new business venture’s survival. Based on an extensive literature review of customer cognitive legitimacy, this book examines the consistent conceptualisation of the concept and its dimensional structure. This consistent conceptualisation facilitates the development of the reliable and valid three-dimensional customer cognitive legitimacy scale in 10 studies. The scale is based on potential customers’ interest in acquiring knowledge about a product and the company responsible for it, their perception of the company’s and the product’s future, and their perception of how competent the company’s managers are.

scholarly journals A damage model for collagen fibres with an application to collagenous soft tissues

2020 ◽  
Vol 476 (2236) ◽  
pp. 20190821
Author(s):  
Gerhard A. Holzapfel ◽  
Ray W. Ogden
Keyword(s):  
Soft Tissues ◽  
Damage Model ◽  
Three Dimensional ◽  
Collagen Fibres ◽  
Physiological Loading ◽  
Cross Links ◽  
Complex Boundary ◽  
Tail Tendon ◽  
Similar Basis ◽  
Rat Tail

We propose a mechanical model to account for progressive damage in collagen fibres within fibrous soft tissues. The model has a similar basis to the pseudoelastic model that describes the Mullins effect in rubber but it also accounts for the effect of cross-links between collagen fibres. We show that the model is able to capture experimental data obtained from rat tail tendon fibres, and the combined effect of damage and collagen cross-links is illustrated for a simple shear test. The proposed three-dimensional framework allows a straightforward implementation in finite-element codes, which are needed to analyse more complex boundary-value problems for soft tissues under supra-physiological loading or tissues weakened by disease.

scholarly journals Mechanical stimulation of single cells by reversible host-guest interactions in 3D microscaffolds

2020 ◽  
Vol 6 (39) ◽  
pp. eabc2648
Author(s):  
Marc Hippler ◽  
Kai Weißenbruch ◽  
Kai Richler ◽  
Enrico D. Lemma ◽  
Masaki Nakahata ◽  
...  
Keyword(s):  
Single Cells ◽  
Three Dimensional ◽  
Stimuli Responsive ◽  
Traction Forces ◽  
Set Point ◽  
Cellular Processes ◽  
Laser Lithography ◽  
Cross Links ◽  
Tensional Homeostasis ◽  
Myosin Motors

Many essential cellular processes are regulated by mechanical properties of their microenvironment. Here, we introduce stimuli-responsive composite scaffolds fabricated by three-dimensional (3D) laser lithography to simultaneously stretch large numbers of single cells in tailored 3D microenvironments. The key material is a stimuli-responsive photoresist containing cross-links formed by noncovalent, directional interactions between β-cyclodextrin (host) and adamantane (guest). This allows reversible actuation under physiological conditions by application of soluble competitive guests. Cells adhering in these scaffolds build up initial traction forces of ~80 nN. After application of an equibiaxial stretch of up to 25%, cells remodel their actin cytoskeleton, double their traction forces, and equilibrate at a new dynamic set point within 30 min. When the stretch is released, traction forces gradually decrease until the initial set point is retrieved. Pharmacological inhibition or knockout of nonmuscle myosin 2A prevents these adjustments, suggesting that cellular tensional homeostasis strongly depends on functional myosin motors.

Ultrafast shape recognition for similarity search in molecular databases

2007 ◽  
Vol 463 (2081) ◽  
pp. 1307-1321 ◽  
Author(s):  
Pedro J Ballester ◽  
W. Graham Richards
Keyword(s):  
Biological Activity ◽  
Three Dimensional ◽  
Molecular Shape ◽  
Scientific Disciplines ◽  
Distance Distributions ◽  
Molecular Databases ◽  
Hard Problems ◽  
Data Explosion ◽  
Novel Drug ◽  
Drug Leads

Molecular databases are routinely screened for compounds that most closely resemble a molecule of known biological activity to provide novel drug leads. It is widely believed that three-dimensional molecular shape is the most discriminating pattern for biological activity as it is directly related to the steep repulsive part of the interaction potential between the drug-like molecule and its macromolecular target. However, efficient comparison of molecular shape is currently a challenge. Here, we show that a new approach based on moments of distance distributions is able to recognize molecular shape at least three orders of magnitude faster than current methodologies. Such an ultrafast method permits the identification of similarly shaped compounds within the largest molecular databases. In addition, the problematic requirement of aligning molecules for comparison is circumvented, as the proposed distributions are independent of molecular orientation. Our methodology could be also adapted to tackle similar hard problems in other fields, such as designing content-based Internet search engines for three-dimensional geometrical objects or performing fast similarity comparisons between proteins. From a broader perspective, we anticipate that ultrafast pattern recognition will soon become not only useful, but also essential to address the data explosion currently experienced in most scientific disciplines.

THERMOREVERSIBLE CROSS-LINKING MALEIC ANHYDRIDE GRAFTED CHLOROBUTYL RUBBER WITH HYDROGEN BONDS (COMBINED WITH IONIC INTERACTIONS)

2014 ◽  
Vol 87 (3) ◽  
pp. 459-470 ◽  
Author(s):  
Lin Li ◽  
Jin Kuk Kim
Keyword(s):  
Hydrogen Bonds ◽  
Maleic Anhydride ◽  
Ionic Interactions ◽  
Cross Linking ◽  
External Energy ◽  
Scanning Calorimetry ◽  
Ionic Bonds ◽  
Cross Links ◽  
Ionic Hydrogen Bonds ◽  
Chlorobutyl Rubber

ABSTRACT Thermoreversible cross-linking polymers are designed based on reversible cross-linking bonds. These bonds are able to reversibly dissociate and associate upon the input of external energy, such as heat or light. Reprocessibility is possible for this kind of material. The objective was to thermoreversibly cross-link maleic anhydride grafted chlorobutyl rubber (MAH-g-CIIR) via a reaction with octadecylamine, with an excess to obtain amide-salts, which form both hydrogen bonds and ionic interactions. X-ray diffraction experiments showed the presence of microphase-separated aggregates that acted as physical cross-links for both the MAH-g-CIIR precursor and amide-salts. The tensile properties were improved by converting MAH-g-CIIR to amide-salts, because of the combination of hydrogen bonding and ionic interactions. The cross-linked materials could be repeatedly compression molded at 155 °C into homogeneous films. The differential scanning calorimetry curves and Fourier transform infrared spectra indicate that hydrogen bonds are of a thermoreversible nature, but the recovery of ionic bonds is impossible. After treatment with heating-cooling for up to three cycles, the tensile strength of the thermoreversible cross-linking CIIR was greatly reduced. The gradual reduction in the effectiveness of the ionic-hydrogen bonds is the major contribution to the reprocessibility of these materials.

scholarly journals Video-rate multimodal multiphoton imaging and three-dimensional characterization of cellular dynamics in wounded skin

2020 ◽  
Vol 13 (02) ◽  
pp. 2050007
Author(s):  
Joanne Li ◽  
Madison N. Wilson ◽  
Andrew J. Bower ◽  
Marina Marjanovic ◽  
Eric J. Chaney ◽  
...  
Keyword(s):  
Cell Tracking ◽  
Skin Diseases ◽  
Ex Vivo ◽  
Three Dimensional ◽  
Biological Information ◽  
Cellular Dynamics ◽  
Multiphoton Imaging ◽  
Cellular Events ◽  
Analysis Platform

To date, numerous studies have been performed to elucidate the complex cellular dynamics in skin diseases, but few have attempted to characterize these cellular events under conditions similar to the native environment. To address this challenge, a three-dimensional (3D) multimodal analysis platform was developed for characterizing in vivo cellular dynamics in skin, which was then utilized to process in vivo wound healing data to demonstrate its applicability. Special attention is focused on in vivo biological parameters that are difficult to study with ex vivo analysis, including 3D cell tracking and techniques to connect biological information obtained from different imaging modalities. These results here open new possibilities for evaluating 3D cellular dynamics in vivo, and can potentially provide new tools for characterizing the skin microenvironment and pathologies in the future.

Sign in / Sign up

Export Citation Format

Share Document