-
Two Recent Research Progress on Polymers
Sugar-Based Polymers from d-Xylose: Living Cascade Polymerization, Tunable Degradation, and Small Molecule Release Biodegradable bio-based polymers provide options for chemical recycling, and they can be used for storing and releasing useful molecules. Scientist Tae-Lim Choi and colleagues from Seoul National University, South Korea, have developed a class of sugar-based polymers that can be degraded by acid hydrolysis. The researchers also integrated “cargo” molecules in the polymer, which are designed to break apart after the polymer degrades. The study, published in the journal Angewandte Chemie, stated that degradable cargo polymers are very important for medical and sensor applications. In this study, enyne monomers derived from D-xylose underwent living cascade polymerizations to prepare…
-
Oral Nano Drug Delivery System Absorption Mechanism
Oral absorption of nanomedicine means that nanomedicine enters the blood circulation through the gastrointestinal tract. Nanomedicine has a very complicated process after entering the body, interacting with the components in the biological system (such as proteins and cells), and has unique distribution, clearance, metabolism and immune response behaviors in the body. There are three main ways for nanoparticles to be absorbed in the gastrointestinal tract: 1. Cell bypass channel transport; 2. Transcellular uptake by intestinal epithelial cells; 3. Phagocytosis by microfold cells (M cells) in Peyer’s patches in the ileum. Absorption through M cells is the main absorption route of oral nanoparticles. When the nanoparticles enter the gastrointestinal tract, part…
-
Oral Drug Absorption Barrier
Oral drugs enter the gastrointestinal tract by mouth, and then undergo digestion and absorption in the gastrointestinal tract. Studies have shown that the gastrointestinal mucosa is attached to the gastrointestinal tract, which is a key barrier affecting the absorption of oral drugs. Studies have found that the gastrointestinal mucosa is covered with a 100-150gm thick aqueous mucosa layer secreted by goblet cells, which is the rate-limiting step for the drug to reach the surface of intestinal epithelial cells. Below the mucosal layer are columnar epithelial cells with tight junctions. In the cell layer there are intestinal epithelial cells, goblet cells, endocrine cells and Peyer’s cells. The epithelial cell layer faces…
-
New Research Reveals the Molecular Mechanism of Cardiolipin
Cardiolipin is a unique phospholipid with a very interesting chemical and specific ultrastructural characteristics. In a research report published in the journal Science Advances in 28 Aug 2020, scientists from Johns Hopkins University and other institutions studied yeast and revealed the molecular mechanism of the fatty compound cardiolipin that helps produce cellular energy. This related research results are expected to help clarify the pathogenesis of diseases that affect human metabolism, such as heart disease, diabetes, and Bath syndrome. Cardiolipin is present in almost every cell of the body. It is located in the maze of cell membranes that make up mitochondria. It is believed to help mitochondria produce mitochondria create adenosine triphosphate (ATP), which is a…
-
What Is Chitosan?
Chitosan is the second most abundant biopolymer in the world, only less than cellulose. It is a versatile biopolymer with unique properties, and is nontoxic, biodegradable and biocompatible. Chitosan is discovered by Rouget in 1859, when the chitin was treated with hot potassium hydroxide solution. At present, chitosan is mainly extracted from shrimp shells or crab shells. Application of Chitosans Chitosan has various applications in a very wide range of fields due to its good biocompatibility, especially in pharmaceuticals (drug delivery, equipment and wound dressings), cosmetics, textile and food industries, and agriculture and the environment industry. Medical Use Chitosan is can used in medical fields. It can be used as a burn dressing and wound healing agent. After dressing…
-
Why are Sphingomyelin Liposomes More Popular?
Sphingomyelin is a membrane phospholipid composed of sphingosine, fatty acid, phosphoric acid and nitrogenous bases. Among them, the fatty acyl group and the amino group are connected by an amide bond, and the formed sphingosine is also called ceramide; afterwards, phosphocholine (or phosphoethanolamine) is connected to the C-1 hydroxyl group of ceramide, and then sphingomyelin be composed. Existing studies have shown that the synthesis of sphingomyelin involves the enzymatic transfer of phosphocholine, from phosphatidylcholine to ceramide. The first step in the synthesis of sphingomyelin is the condensation of L-serine and palmitoyl-CoA. Serine palmitoyl transferase catalyzes this reaction. The product of this reaction is reduced to produce dihydrosphingosine. dihydrosphingosine undergoes N-acylation and…
-
Oral Nano-drug Delivery System 2
The previous article introduced the relevant information about choosing liposomes and nanoparticles as drug carriers in oral nano-drug delivery systems. This article will continue to introduce the feature of microemulsions, polymers, dendrimers and nano-drug crystals as oral drug carriers. Microemulsion Microemulsion is formed by mixing water phase, oil phase, surfactant and co-surfactant in appropriate proportions, with a particle size of 10~100mpm, transparent or translucent, low viscosity, isotropic thermodynamics and kinetics For a stable oil-water mixing system, there is also literature that the particle size of the microemulsion is 20~200nm. Microemulsions have received extensive attention in recent years because of their significant targeting, sustained-release effects and strong solubilization effects on poorly soluble…
-
New Research Develops a New X-ray Responsive Degradation Nano-drug Carrier System
Chemotherapy is a commonly used clinical treatment for tumors, but single-molecule chemotherapeutics have low bioavailability and large side effects, which could be a significant burden to patients and their families. Nanotechnology prepares single-molecule chemotherapeutic drugs into nanometer drugs, which can achieve tumor targeting and controllable release of chemotherapeutic drugs, thereby improving the therapeutic effect and reducing toxic and side effects, which is conducive to achieving high-efficiency and low-toxicity chemotherapy. Mesoporous silica nanomaterials have the advantages of simple synthesis, controllable structure, good chemical tailoring and biocompatibility, and are a nano-medicine carrier platform with good clinical application prospects. According to the characteristics of micro-acid, hypoxia and high redox in the tumor microenvironment, researchers have developed a…
-
The Most Cited Literature on Block Copolymer Micelles
Block copolymer micelles are generally formed by the self-assembly of either amphiphilic or oppositely charged copolymers in aqueous medium. In this article, the editor summarizes the most cited research results that scientists have made on block copolymer micelles, and hope you can find what you need. What are Block Copolymer Micelles? Block copolymer micelles are generally formed by the self-assembly of either amphiphilic or oppositely charged copolymers in aqueous medium. The hydrophilic and hydrophobic blocks form the corona and the core of the micelles, respectively. The presence of a nonionic water-soluble shell as well as the scale (10-100 nm) of polymeric micelles are expected to restrict their uptake by the mononuclear phagocyte system and…
-
Research Progress of Self-Assembled Drug Delivery Systems 2
Regarding the research progress of self-assembled drug delivery systems, we have introduced the clinical research on acyclovir and didanosine self-assembled systems in previously article. This article will continue to introduce the research results of other drug self-assembly systems, such as zidovudine, isoniazid and gemcitabine self-assembly drug delivery systems. Zidovudine Zidovudine (AZT) is the first anti-HIV drug to be marketed and is still the first-line drug. Nano-preparations of zidovudine include liposomes and nanoparticles. As they may obtain the property of sustained release, lymphatic targeting, and macrophage system targeting,these nano preparations can reduce or eliminate the bone marrow toxicity caused by the distribution of zidovudine in the bone marrow tissue. Since zidovudine, as nucleoside analogs, must be…
