Liposome Preparation Services

BOC Sciences is a leading provider of liposome preparation services, offering a wide range of options for researchers and companies seeking to encapsulate drugs or other molecules in liposomes. Liposomes are tiny vesicles composed of a phospholipid bilayer that can be used to deliver drugs or other molecules to specific targets in the body. By encapsulating molecules in liposomes, researchers can improve the stability, solubility and bioavailability of their compounds and target them to specific tissues or cells.

What are Liposomes?

Liposomes are ultramicrospherical particles with a bilayer structure formed by self-aggregation in water using phospholipids as wall material. The hydrophilic heads of the phospholipids form the inner and outer surfaces of the bilayer, and the lipophilic tail fatty acid chains form the hydrophobic core region of the bilayer. The size of liposomes ranges from 20 nm to several microns, and they may be composed of one or several concentric or non-concentric membranes, each with a thickness of about 4 nm. According to the size of liposomes and the number of lipid bilayers, liposomes can be divided into single-chamber liposomes and multi-chamber liposomes. Among them, single-chamber liposomes can be divided into small single-chamber liposomes (SUV, 20-100 nm), large single-chamber liposomes (LUV, >100 nm) and giant single-chamber liposomes (GUV, >100 nm); multicompartment liposomes can be divided into multicompartment liposomes (MLV, >500 nm) and multivesicular liposomes (MVV, >1000 nm).

What Can We Offer?

BOC Sciences is committed to providing customers with high-quality liposome preparation services, focusing on quality, reliability and customer satisfaction. Our team of experienced scientists works closely with each customer to understand their specific needs and develop custom solutions to meet those needs. Whether you are a researcher looking to encapsulate drugs in liposomes for in vitro studies, or a company looking to develop liposomal drug delivery systems for clinical use, BOC Sciences can help you achieve your goals.

Liposome Preparation Services

BOC Sciences offers comprehensive liposome preparation services, including liposome formulation, encapsulation and characterization. Our team of experienced scientists can help you design and optimize liposome formulations to meet your specific needs, whether you want to improve the stability of your drug, enhance its solubility, or target it to a specific tissue or cell type. We can also help you encapsulate a variety of molecules into liposomes, including small molecules, peptides, proteins, nucleic acids, and more.

Liposome Characterization Services

One of the key advantages of working with BOC Sciences is our expertise in liposome characterization. We use a variety of techniques to characterize liposomes, including dynamic light scattering, zeta potential analysis, and transmission electron microscopy to ensure your liposome formulations meet your specifications. Our team can also help you optimize the stability, drug release kinetics and targeting efficiency of your liposome formulation to ensure your liposomes are effective in the body.

Our Liposome Preparation Technology

Multilamellar liposomes (MLVs) can be formed when phospholipids are dispersed in an aqueous solution under gentle stirring. However, the preparation of large unilamellar liposomes (LUVs) and small unilamellar liposomes (SUVs) requires a large amount of energy input to destroy multiple lamellar liposomes. The structure of chamber liposome MLV and vesicular liposome MVV, such as sonication, homogenization, heating, etc.

Non-mechanical Methods

• Thin-layer dispersion

The thin film dispersion method is the Bangham method. This method first dissolves the lipid in an organic solvent, and then removes the organic solvent through a rotary evaporator. After the lipids form a film, the aqueous phase is added to form a relatively uniform suspension, which is the liposome. The thin film dispersion method is the easiest method to prepare liposomes so far, but the encapsulation efficiency is low and the particle size is large.

• Freeze-thawing Method

The preliminary preparation process of the repeated freezing and thawing method is similar to that of the film dispersion method. After obtaining the liposome suspension, the liposomes are obtained through repeated freezing and thawing operations. The repeated freezing and thawing method has the advantages of high encapsulation rate and good uniformity, but it requires a long time for preparation.

• Solvent Injection Method

The organic solvent injection method first dissolves the lipid in an organic solvent, and then injects the lipid organic solution into a high-speed stirred aqueous phase to form a liposome suspension. Finally, the organic solvent is removed by decompression or nitrogen blowing to obtain a liposome solution.

• Reverse-phase Evaporation Technique

The reverse phase evaporation method is to first dissolve the lipid material in an organic solvent, then add the aqueous solution, and finally remove the organic solution to obtain the liposome solution.

Mechanical Methods

• Extrusion Method

The extrusion method is that the liposome passes through the filter membrane with a pore size smaller than its own particle size through the action of external force. Due to the action of shear force, it is deformed, resulting in rupture, and then the ruptured double layer is immediately recombined to form a smaller liposome, and finally reaches the other side of the filter membrane. The extrusion method does not contact with organic solvents and detergents, and the preparation process is simple and reproducible.

• Ultrasonic Disperse

There are two types of ultrasonic dispersion methods: direct probe sonicator and indirect bath sonicator. Probe ultrasound is a common method for preparing small single-chamber liposomes. It can destroy multi-chamber liposomes to form more uniform small single-chamber liposomes. Water bath ultrasound is less destructive than probe ultrasound. Moreover, the reproducibility is high and the liposomes are more uniform.

• High-pressure Homogenization

This method mainly relies on the role of high-pressure homogenizer. After dissolving the lipid material, it is added to the aqueous phase containing the surfactant to form the colostrum, which is then processed by the high-pressure homogenizer to form a liposome solution with a small particle size and uniform distribution. The liposomes prepared by this method have small particle size, uniform particle size, good stability and narrow distribution range. This method has good repeatability and can be produced on a large scale.

• Dynamic High-pressure Microfluidization (DHPM)

DHPM is a new high-pressure homogenization technology. Its working principle is to use a hydraulic pump to pass the fluid and generate high pressure, so that the fluid is dispersed into two or more thin streams in the micropores in the impact chamber, and is subjected to strong high-speed impact. During the impact process, a large amount of energy is converted instantly, resulting in a huge pressure drop, thereby achieving the comprehensive effects of high-speed impact, high-frequency shear, cavitation, high-frequency vibration, and instantaneous pressure drop. Under 200MPa pressure, the purpose of material refinement, emulsification, homogenization and modification can be achieved in less than 5s. Liposomes prepared by DHPM have the advantages of small particle size, narrow distribution, high encapsulation rate, and can achieve large-scale and continuous production.

Case Study

Recently, Jeon et al. developed a theranostic multilayered nanomaterial by inserting additional liposomal layer (LAL) into gold (Au)-coated liposomes prepared by TFH method. Additional liposome layers can be further functionalized with PEG groups (to enhance in vivo stability) and radiolabeling (for in vivo imaging). In vivo photothermal therapy (PTT) studies demonstrated that the appropriate combination of intravenous LAL and laser irradiation was able to inhibit tumor progression in a 4T1 orthotopic tumor mouse model. This liposomal nanocarrier may become a promising theranostic PTT nanoplatform for the treatment of metastatic lesions as it exhibits high stability, tumor targeting efficiency, and imaging capabilities.[1]

FAQ

1. What are the lipid mixtures for the preparation of liposomes?

Several lipid mixtures are available for the preparation of liposomes, depending on the desired properties and application of the liposomes. Some common lipid mixtures include: phosphatidylcholine (PC), phosphatidylethanolamine (PE), phosphatidylserine (PS), cholesterol, sphingomyelin.

2. What is the heating method for liposome preparation?

Liposomes can be prepared through various heating methods such as water bath heating, sonication, microwave heating, dry heat heating, freeze-thaw cycles, etc.

Reference

1. Jeon, M. er al. Development of theranostic PEGylated liposomal Au-liposome for effective tumor passive targeting and photothermal therapy. J. Nucl. Med. 2020, 61(Suppl. 1): 1076.