4 results about "Dihydroxyphenylalanine" patented technology

The application provides a kind of load exosome composite hydrogel and preparation method thereof, belong to biomaterial and drug delivery technical field;Its preparation method includes: modified chitosan;Modified hyaluronic acid;Preparation of biphasic calcium phosphate nanoparticles;Preparation of composite hydrogel.The application is through nucleophilic ring-opening reaction of 1,2-epoxy butane and the hydroxyl group of chitosan, form hydroxybutyl ether bond, give hydroxybutyl chitosan temperature sensitive characteristics, then, again, after activation 3,4-dihydroxyphenylalanine is condensed with hydroxybutyl chitosan, form amide bond, to graft 3,4-dihydroxyphenylalanine on hydroxybutyl chitosan, after modification of chitosan, 3,4-dihydroxyphenylalanine can form strong adhesion interface with cartilage, synovial membrane and other tissues through hydrogen bond, pi-pi stacking and metal coordination, thereby effectively prolonging the residence time of hydrogel in joint.

This invention discloses a water-soluble melanin CEST contrast agent, its preparation method, and its application, relating to the field of magnetic resonance imaging contrast agent technology. This contrast agent, its preparation method, and its application aim to solve the technical problem that existing contrast agents containing paramagnetic metals can damage liver and kidney function. This water-soluble melanin CEST contrast agent comprises the following components by weight: 2-3 parts ammonia, 40 parts ethanol, 100 parts deionized water, and 0.5 parts reaction substrate. The chemical shift corresponding to this contrast agent preparation method is 4.0 ppm, exhibiting good adaptability to acidic environments and suitability for use in the tumor microenvironment. It is polymerized using dopamine hydrochloride or 3,4-dihydroxyphenylalanine, with inexpensive, simple, and readily available raw materials, simple synthesis, and easy large-scale preparation. It achieves tumor imaging without the need for paramagnetic metal ions, avoiding the damage to liver and kidney function caused by heavy metal ions.

The invention discloses a preparation method of a nano-copper-based conductive composite material. The invention relates to the technical field of conductive composite materials, which comprises the following preparation steps: step 1, preparation of a poly (catechol-polyamine)-copper precursor suspension: S11, preparing a mixed monomer solution which comprises a catechol-polyamine system, 3, 4-dihydroxyphenylalanine, gallic acid and Tween-80; and S12, adjusting the pH value of the mixed monomer solution to 8.5-9.0 by adopting a Tris-HCl buffer solution, and then sequentially adding copper sulfate, a composite oxidation system, dithiothreitol and phytic acid into the mixed monomer solution. According to the preparation method, a catechol-polyamine system and 3, 4-dihydroxyphenylalanine gallic acid are subjected to synergistic polymerization, a poly (catechol-polyamine) coating layer with a steric hindrance effect is formed on the surfaces of copper ions, meanwhile, tween-80 optimizes the hydrophilicity and hydrophobicity of the surfaces of the particles, dithiothreitol regulates and controls charge distribution on the surfaces of the particles, and the copper ions can be effectively dispersed in the particles. And particle agglomeration is inhibited from the source through multiple effects.

This invention discloses a method for preparing a nano-copper-based conductive composite material, comprising the following preparation steps: Step 1, preparation of a poly(catechol-polyamine)-copper precursor suspension: S11, preparing a mixed monomer solution, wherein the mixed monomer solution contains a catechol-polyamine system, 3,4-dihydroxyphenylalanine, gallic acid, and Tween-80; S12, adjusting the pH of the mixed monomer solution to 8.5-9.0 using Tris-HCl buffer, and then sequentially adding copper sulfate, a composite oxidation system, dithiothreitol, and phytic acid. In this invention, through the synergistic polymerization of the catechol-polyamine system and 3,4-dihydroxyphenylalanine gallic acid, a poly(catechol-polyamine) coating layer with steric hindrance effect is formed on the surface of copper ions. Simultaneously, Tween-80 optimizes the hydrophilicity / hydrophobicity of the particle surface, and dithiothreitol regulates the charge distribution on the particle surface. These multiple effects fundamentally inhibit particle aggregation.