What are nanospheres? What is its purpose?

Microspheres are a modern industrial basic material with a diameter smaller than hair. Without them, mobile phone screens would not be able to be produced, and the efficacy of drugs would be difficult to achieve. Nanomicrospheres typically refer to microspheres with particle sizes ranging from 1 to 100 nm, at which their properties undergo significant changes.

What are the materials used to make nanospheres?

The materials used to produce nanospheres can be divided into two categories: natural biomaterials and synthetic polymer materials. Natural biomaterials mainly include chitosan, collagen, starch, liposomes, lipoproteins, etc. Chitosan, collagen, and starch are the matrix components of tissues, which have good biocompatibility and biodegradability, low cytotoxicity, and the degradation products can be absorbed by the body; But the disadvantage is poor mechanical strength and difficult to control the degradation rate.

Synthetic polymer materials mainly include PEG, (lactic acid hydroxyacetic acid) polymer (PLGA), and polyvinyl alcohol (PVA), which have been well applied in drug transportation.

How to make nanospheres?

Ion crosslinking method is one of the basic methods to produce nanospheres, which is suitable for nanospheres made of chitosan, sodium alginate, etc. Its main principle is that the materials used as drug carriers are separated from lotion by ionic crosslinking, and drugs are embedded in the carrier by hydrogen bond interaction and hydrophobic interaction, so as to prepare drug loaded microspheres. This method has mild preparation conditions and does not use harmful reagents to the human body, making it one of the ideal preparation methods for drug loaded microspheres.

Typical preparation methods for nanospheres include "emulsification solvent evaporation method" and "microfluidic method". "Emulsion solvent volatilization method" is to dissolve the model drug in organic solvent first, then drop it into the aqueous phase containing surfactant, form an oil/water phase lotion under the high-speed shear of the homogenizer, remove the volatile organic solvent in the dispersed phase of the lotion through normal pressure or reduced pressure, harden the nanoparticle, and finally collect nanoparticle from the aqueous suspension through freeze drying. "Microfluidic method" is a technology to control two or more immiscible micro volume liquids in a micro scale channel, and continuously and controllably produce single lotion droplets and multiple lotion droplets with highly monodisperse size.

What are the characteristics of the application of nanospheres in the medical field?

The specific surface area of one gram of nanospheres is equivalent to that of a football field, and nanospheres have extremely strong adsorption performance due to their huge specific surface area. If special functional groups are linked to the surface of the microspheres, they can selectively adsorb certain substances, which makes them a key material for drug separation and purification.

In addition, the nanospheres themselves have no pharmacological effects and do not undergo chemical reactions with drugs. However, nanospheres as drug carriers have the advantages of improving drug utilization and selectivity, reducing drug damage to normal tissues, reducing toxic side effects, and being able to target drug delivery to lesion sites, achieving targeted drug delivery.