• The main advantages of these systems are:
• High circulation times
• Enhancement of permeability and retention effects
• Reduction of toxic side effects
• Release at the therapeutic target
• Controlled biodistribution
• Reduced dose
• Increased treatment efficacy

Delivery of drug carriers to target cells by recognition of surface biomarkers is a promising approach with clear advantages. First, cellular specificity may reduce toxicity and keep adverse reactions to the minimum. Second, introduction of the cellular specificity may overcome the limitations of some previous therapies.

Nanoparticle interaction with cells and the cellular internalization machinery is quite complex and it has been challenging to identify unifying principles for particle internalization via specific pathways across cell types. Encapsulation of therapeutic agents into nanoparticles with a particular affinity for an internalization pathway is potentially highly efficient mode of membrane targeting. However, most cells are not highly specialized to recognize particles alone as targets for selective uptake, with the exception of professional scavenging cells such as reticuloendothelial cells and macrophages.

Addition of targeting ligands with specificity for receptors, either protein, carbohydrate or lipid based, to nanoparticles is an ideal strategy for targeting of nanoparticles to particular cells and/or for reaching specific membrane encapsulated compartments in cells.

However, in some cases biological materials introduced into cells via endocytosis lose their biological activity due to acidic media. In these cases, the use of fusogenic liposomes are an alternative for the release of drugs. Specifically, is expected to become a highly useful tool for use in gene therapy. The high efficiency of this system is attributable to the fact that materials introduced by membrane fusion can escape lysosomal degradation and reach the cytoplasm in an intact form.

• The main advantages of these systems are:
• High circulation times
• Enhancement of permeability and retention effects
• Reduction of side effects
• Release at the therapeutic target

Delivery of drug carriers to target cells by recognition of surface biomarkers is a promising approach with clear advantages. First, cellular specificity may reduce toxicity and keep adverse reactions to the minimum. Second, introduction of the cellular specificity may overcome the limitations of some previous therapies.

Nanoparticle interaction with cells and the cellular internalization machinery is quite complex and it has been challenging to identify unifying principles for particle internalization via specific pathways across cell types. Encapsulation of therapeutic agents into nanoparticles with a particular affinity for an internalization pathway is potentially highly efficient mode of membrane targeting. However, most cells are not highly specialized to recognize particles alone as targets for selective uptake, with the exception of professional scavenging cells such as reticuloendothelial cells and macrophages.

Addition of targeting ligands with specificity for receptors, either protein, carbohydrate or lipid based, to nanoparticles is an ideal strategy for targeting of nanoparticles to particular cells and/or for reaching specific membrane encapsulated compartments in cells.

However, in some cases biological materials introduced into cells via endocytosis lose their biological activity due to acidic media. In these cases, the use of fusogenic liposomes are an alternative for the release of drugs. Specifically, is expected to become a highly useful tool for use in gene therapy. The high efficiency of this system is attributable to the fact that materials introduced by membrane fusion can escape lysosomal degradation and reach the cytoplasm in an intact form.

• Wide range of sizes, shapes and surface properties
• Tunable optical properties
• Easily surface modification
• Good biocompatibility
• Drugs can be encapsulated within the nanoparticles or attached to the surface.

Delivery of drug carriers to target cells by recognition of surface biomarkers is a promising approach with clear advantages. First, cellular specificity may reduce toxicity and keep adverse reactions to the minimum. Second, introduction of the cellular specificity may overcome the limitations of some previous therapies.

Nanoparticle interaction with cells and the cellular internalization machinery is quite complex and it has been challenging to identify unifying principles for particle internalization via specific pathways across cell types. Encapsulation of therapeutic agents into nanoparticles with a particular affinity for an internalization pathway is potentially highly efficient mode of membrane targeting. However, most cells are not highly specialized to recognize particles alone as targets for selective uptake, with the exception of professional scavenging cells such as reticuloendothelial cells and macrophages.

Addition of targeting ligands with specificity for receptors, either protein, carbohydrate or lipid based, to nanoparticles is an ideal strategy for targeting of nanoparticles to particular cells and/or for reaching specific membrane encapsulated compartments in cells.

However, in some cases biological materials introduced into cells via endocytosis lose their biological activity due to acidic media. In these cases, the use of fusogenic liposomes are an alternative for the release of drugs. Specifically, is expected to become a highly useful tool for use in gene therapy. The high efficiency of this system is attributable to the fact that materials introduced by membrane fusion can escape lysosomal degradation and reach the cytoplasm in an intact form.