Immunoliposomes

Nanotechnology has given a whole new dimension to drug delivery systems, especially targeting therapies. Among these recent developments, immunoliposomes are considered a very potent tool since they utilize the specificity of antibodies to deliver drugs more effectively to their target cells. BOC Sciences has continuously developed various types of immunoliposome formulation to provide advanced solutions for researchers and healthcare professionals in tumor therapy, inflammation therapy, and vaccine delivery. In addition, we offer a range of custom liposome services for you to choose from. At BOC Sciences, you're sure to make a difference in liposomes.

Immunoliposomes Definition

Immunoliposomes are modified liposomes that have antibodies attached to their surface for the recognition of target cells and hence enhance the targeting of the liposome. This unique modification enables the selective targeting of cells expressing specific antigens and, by this way, increases the efficacy of delivered therapeutic agents. While conventional liposomes might disperse the contents indiscriminately, immunoliposomes are designed in such a way that their delivery of drugs is directed exactly to the place of action. Such a targeted approach is fully effective in maximizing the therapeutic effect of encapsulated drugs, besides minimizing their side effects, and therefore immunoliposomes become an attractive alternative for the treatment of diseases such as cancer, where precision is of essence. For instance, monoclonal antibody 3G against gastric cancer cell surface antigen was coupled to mitomycin (MMC) liposome to prepare an immunoliposome. This immunoliposome exhibited a 4-fold higher M85 killing effect on gastric cancer target cells in vivo than free MMC.

Immunoliposome formation. (Parveen, N.;et al, 2022)

Characteristics of Immunoliposomes

• Immunoliposomes have their surface modified by attaching specific antigenic antibodies or their fragments in such a way that they are able to recognize selectively and deliver the target specifically against some cells or tissues.
• Liposomes have excellent drug-carrying properties and are capable of encapsulating many types of water-soluble and fat-soluble drugs.
• Immunoliposomes are capable of targeting drugs to tumor cells, sites of inflammation, or other antigens expressed on the surface of specific cells with specific recognition by antigens or antibodies.
• Immunoliposomes can carry drugs in chemical, carrier gene, nucleic acid, and other biologically active substances.

Immunoliposomes Mechanism of Action

The mechanism of the action of immunoliposomes is based on the selective interaction with target cells. After administration, the nanocarriers circulate in the blood flow until they come across a target cell expressing the corresponding antigen. An antibody on the surface of the immunoliposome interacts with the antigen; such an interaction is specific, and it mediates the internalization of the liposome into the target cell through endocytosis. Inside the cell, the therapeutic payload of the immunoliposome can be released and act locally on its target. This greatly increases the drug's therapeutic index by concentrating the active agent at the site of disease, while reducing exposure to healthy tissues-a clear advantage in the treatment of cancer.

Development of Immunoliposomes

• First generation immunoliposomes: The first generation immunoliposomes are liposomes with monoclonal antibodies attached. Through the specific binding of monoclonal antibodies to target cells, the liposome-encapsulated drug is directed to the target tissue, giving the liposome active targeting properties.
• Second generation immunoliposomes: Second-generation IML includes PEG-containing, long-circulating liposomes that enable binding of antibodies or ligands to the liposome surface.
• Third generation immunoliposomes: In order to increase the targeting properties of long-lived liposomes, a new type of liposome is obtained by attaching antibodies or other ligands to the ends of polymer (e.g., PEG) chains on the surface of the long-lived liposome, thus avoiding the interference of the PEG chains with the recognition of the target site.

Immunoliposomes from BOC Sciences

BOC Sciences offers a diverse array of immunoliposome products, each designed to serve specific therapeutic needs and enhance the precision of drug delivery:

• Amine Reactive Liposomes: Amine-reactive liposomes are functionalized liposomes whose molecules or portions can react with amine groups to facilitate binding reactions with amine-containing biomolecules such as proteins, peptides, and antibodies, and are important precursors for the preparation of immunoliposomes.
• Azide Reactive Liposomes: Azide reactive liposomes can react with other molecules or compounds having complementary reactive groups, such as alkyne groups (-C = CH), to form covalent bonds via copper-free click chemistry.
• Biotinylated Liposomes: Biotinylated liposomes have a biotinylated portion and are primarily used for coupling to proteins or biotinylates (e.g., antibodies) with affinity (streptavidin).
• Carboxylic Acid Reactive Liposomes: Carboxylic acid reactive liposomes are a special type of liposomal nanocarrier designed to selectively interact with molecules or surfaces containing carboxylic acid groups.
• DBCO Reactive Liposomes: DBCO reactive liposomes can be used to deliver a wide range of payloads including chemotherapeutic agents, probes, siRNAs, aptamers, antibodies, etc.
• Folate Liposomes: Folate liposomes can be synthesized by utilizing the carboxyl group of folic acid to react with complementary reactive groups of lipids, cholesterol and proteins.
• Metal Chelating Liposomes: Metal chelating liposomes are a special class of liposomes that contain a metal chelating agent as well as appropriate lipid components.
• Sulfhydryl Reactive Liposomes: Sulfhydryl reactive liposomes contain groups that react with sulfhydryl (thiol) groups to link molecules containing sulfhydryl or thiol groups.
• Pegylated Immunoliposomes: Pegylated immunoliposomes incorporate PEG chains into them, thus enhancing the circulation time by reducing immune clearance, hence improving delivery to target tissues. Due to its enhanced circulation, more time is spent within general circulation that will enable better interaction with target cells.
• Temperature-Sensitive Immunoliposomes: Such immunoliposomes release their drug payload in response to heat and, therefore, are ideal in localized therapies such as hyperthermia of tumors. Temperature may trigger the release of the drug payload at the tumor site, thereby decreasing systemic exposure while enhancing the local therapeutic effect.
• Sterically Stabilized Immunoliposomes: These immunoliposomes also demonstrate prolonged circulation and bioavailability with the addition of protective polymers, maintaining effective drug levels over time at areas of disease.
• Anti-HER2 Immunoliposomes: Anti-HER2 immunoliposomes have shown to target HER2-overexpressing tumor cells specifically, offering therapeutic effects and minimizing harmful effects on healthy tissues.
• Trastuzumab Immunoliposomes: Trastuzumab-conjugated immunoliposomes were developed for the treatment of HER2-positive tumors. The drug delivery with these types of immunoliposomes occurs directly in the cancerous cells having the problem of HER2 overexpression, enhancing the efficacy while sparing the healthy cellular component.

Immunoliposomes Preparation

Preparation of the immunoliposomes is a very step-by-step process, followed by a lot of care taken in order for the particles to be optimally characterized for targeted delivery.

(1) First, the formation of liposomes usually consists of the hydration of a film of lipids. In the process, it naturally forms phospholipid bilayers containing an aqueous core with the therapeutic agent inside.

(2) Other than the formation of liposomes, the next important step is the conjugation of the antibodies on the surface of the liposome. This can be done with several different chemical linkers, including carbodiimide coupling or even click chemistry. These approaches ensure that the antibodies maintain their biological activity while attaching firmly on the surface of the liposome.

(3) After their synthesis, immunoliposomes are subjected to intense characterization in their size, surface charge, and efficiency of encapsulation. The Dynamic Light Scattering (DLS) and HPLC are typical ways to characterize them.

These processes are crucial for optimizing the immunoliposome formulations provided by BOC Sciences, ensuring that each product is tailored for specific therapeutic applications and meets stringent quality standards.

Immunoliposome Function

The main function of immunoliposomes is highly specific delivery of therapeutic agents, thus allowing increasing the overall efficacy of treatment. These advanced carriers can be loaded with a wide range of payloads-from small molecule drugs to nucleic acids and proteins-making them a versatile tool in modern therapeutics. Immunoliposomes exhibit several key functionalities:

• Improved Stability: The lipid bilayer of the liposomes provides a sanctuary for labile drugs, protecting them from degradation in biological fluids before they reach the target site.
• Various Payloads: The therapeutic agents accommodated by immunoliposomes include chemotherapeutics, RNA-based therapies, and proteins. This heterogeneity in payload explains their huge applicability across medical fields and expands their potential impact on patient care.

Immunoliposomes Applications

Immunoliposomes for Drug Delivery

Outside of oncology, immunoliposomes have applications in a wide range of therapeutic areas, such as infectious diseases, autoimmune disorders, and genetic conditions. They are able to ensure the delivery of biologically active substances directly to selected cells, with an extraordinary opportunity for the formulation of targeted therapies, thus highly improving clinical outcomes in patients. This personalized approach is of particular importance in those diseases for which classic systemic treatments are inefficacious or produce unacceptable adverse effects.

Immunoliposomes Targeted Delivery

Immunoliposomes ensure that therapeutic agents reach the intended sites of action with very minimal distribution to non-target tissues. This specificity is essential in limiting side effects and enhancing the effectiveness of treatments, especially among sensitive patient populations in whom off-target effects may translate into significant complications.

Immunoliposomes Gene Therapy

Immunoliposomes have gained great importance in gene therapy for the delivery of nucleic acids like siRNA, mRNA, and plasmid DNA. The targeting of antibodies improves cell-type specificity of the uptake of genetic materials and as such allows for an efficient modulation of gene expression. This opens new perspectives in the therapy of genetic disorders and increases the precision of therapeutic interference.

Immunoliposomes for Cancer Treatment

Immunoliposomes have become one of the powerful tools in cancer therapy and represent a novel, sophisticated approach to target cancer cells selectively, thereby reducing side effects associated with conventional chemotherapy. These engineered liposomes are conjugated with antibodies or antibody fragments that recognize antigens on cancer cells with specificity, thus assuring high precision in the delivery of the drug payload to malignant sites.

Advantages of Immunoliposomes from BOC Sciences

Immunoliposomes are advanced drug-targeting systems in which the unique specificity of antibodies is combined with the drug-carrying capacity of liposomes. The following are some of the major advantages of immunoliposomes provided by BOC Sciences:

• High Targeting Specificity: Immunoliposomes fabricated by BOC Sciences guarantee the delivery of drugs at a diseased cell through its binding with disease-specific antibodies, thus ensuring maximum therapeutic effects with minimum adverse effects on healthy tissues, ideal for specific targeted therapy.
• Improved Drug Stability and Controlled Release: The structure of the immunoliposomes stabilizes the drug payload, preventing degradation during circulation and allowing controlled gradual release that prolongs therapeutic duration, reduces dosing frequency, and enhances ease of use.
• Prolonged Circulation Time with PEGylation: Modification of immunoliposomes with polyethylene glycol (PEG) prolongs their circulation time, increasing the opportunity of reaching target cells and supporting prolonged drug exposure.
• Versatile Drug Loading: Capable of carrying small molecules, proteins, nucleic acids, and other compounds, immunoliposomes are adaptable to various therapeutic needs, from chemotherapy to gene therapy, supporting broad applications in precision medicine. guidance in selecting the appropriate formulation and optimizing experimental designs.
• One-stop Customized Immunoliposome Service: Capable of customization design, BOC Sciences' immunoliposomes will support adjustments in delivery plans based on individuals' needs to assist in personalized studies.
• High Quality and Scalability: BOC Sciences is able to ensure the quality of every batch of immunoliposomes, whether in small batches or scaled up for large-scale production for research or production needs.

BOC Sciences has been taking on even more challenging endeavors in targeted drug delivery through the use of immunoliposome technology, moving options forward for studying precision therapy in a variety of disease conditions. Due to their high targeting precision, good stability, versatility, and adaptability, the immunoliposomes from BOC Sciences can be considered as a powerful platform for personalized medicine and therapy development.

Reference

1. Parveen, N.; et al. Immunoliposomes as an emerging nanocarrier for breast cancer therapy. European Polymer Journal. 2022: 111781.