What is the click chemistry process in filter membrane modification?

As the name suggests, "click chemistry" refers to fast, reliable, and high-yield chemical reactions. It is a concept first proposed by Professor K. Barry Sharpless in 2001. It refers to the use of specific chemical reactions to connect two molecules, like They "click" together. These reactions have the characteristics of high yield, high selectivity, and high reliability, and do not produce by-products, or even if they are produced, they can be easily removed. Therefore, this technology is more suitable for filter membrane modification. In nature, the microporous filter membrane is surface treated to achieve certain specific filtration performance or functions.

There are many click chemistry methods for filter membrane modification, the most commonly used is the copper (I) catalyzed azide-alkyne cycloaddition (CuAAC) reaction using azide and alkyne, azide + alkyne + copper (I) Catalyst → Triazole, the copper (I) catalyst here, such as copper (I) iodide or copper (I) sulfate, mainly functions to promote the reaction. Due to the reaction of azide and alkyne functional groups, a stable The triazole bond is not easily degraded and has the characteristics of high stability and biological inertness; other click reactions, such as strain-promoted azide-alkyne cycloaddition (SPAAC) or thiol-ene reaction, thiol + alkene → thioether , mainly the reaction between thiol (sulfhydryl) group and olefin (alkene) group. The reaction is highly selective and does not require a catalyst. The generated thioether bond is also stable and difficult to degrade. .

The click chemical process is also slightly different due to different reaction types and required modified membrane characteristics, but in general it can be divided into the following steps:

1. Membrane surface functionalization. Before click chemical reaction, the filter membrane surface needs to be functionalized and used to present reactive groups for click chemistry. This can be achieved through a variety of methods, such as plasma treatment, chemical modification properties or coating with linker molecules containing reactive groups, such as introducing amine or thiol groups to the membrane surface as reaction sites for subsequent click reactions.

2. Click chemical reaction. After the membrane surface is properly functionalized, click chemical reaction can be carried out. Taking the CuAAC reaction as an example, azide functionalized molecules or reagents and alkyne functionalized molecules must be combined in the presence of copper (I) catalyst. The reaction proceeds quickly by mixing chemical molecules or reagents, forming stable triazole bonds between the azide and alkyne moieties. Such reactions can occur in solution or directly on the membrane surface, depending on the specific conditions. applications and requirements.

3. Post-click functionalization. After the click chemical reaction, further functionalization steps can be performed to introduce the desired functional groups or molecules onto the modified membrane surface, which can be through some additional click chemical reactions or other bioconjugation techniques. Bioactive molecules, such as antibodies, enzymes or affinity ligands, can be attached to the modified membrane surface to confer special recognition or binding capabilities.

4. Characterization and evaluation. The modified filter membrane should be characterized to evaluate whether the click chemical modification is successful, which can be combined with optical electron microscopy measurement techniques, such as Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) ), atomic force microscopy (AFM) or contact angle measurement, etc., to confirm the presence of the required functional groups and evaluate the surface modification effect of the material, etc.

In summary, by utilizing click chemistry reactions, filtration membranes can be effectively modified with desired functional groups or molecules, thereby enhancing performance and specific applications. Click chemistry methods offer versatility, high yields, and mild reaction conditions, making them ideal for filtration, A valuable tool for membrane surface modification in various fields such as separations, bioconjugation and biosensing. Controlling and understanding this process with click chemistry technology can greatly improve the performance of filter membranes in practical applications. This is also a complex process that requires deep chemical knowledge to accurately control and understand.