Biological targeting with nanoparticles: state of the art

Abstract

Nanoparticles are used in medicine to deliver drugs, for imaging, for vaccination and for local heating of tissue (tumor thermotherapy). If malignant tissue shall be addressed, it is of prime importance to direct the nanoparticles to their target. This can be accomplished by making use of physical effects (e.g., the EPR effect: enhanced permeation and retention) or by chemical modification of the nanoparticles to specifically recognize cells or tissues. The efficiency of the targeting can be assessed by in vitro cell culture experiments and also in vivo in animal experiments. As they are closest to the practical clinical application, in vivo imaging methods are particularly suitable to monitor the targeting. In general, a limited colloid-chemical stability of the nanoparticles in a biological environment and the formation of a protein corona around the nanoparticle may constrain their targeting ability. The current state of such targeting strategies is reviewed and discussed.

Biological and Medical Applications of Calcium Phosphate Nanoparticles

“…[87] It was also found that nanoparticleso f3 0-150 nm are found in bone marrow,h eart, kidneya nd stomach whereas nanoparticles with as ize of 150-300 nm mainly end up in the liver and in the spleen. [88] Furthermore, the cellular uptake of nanoparticles can be strongly influenced by ap rotein corona, which coversthe particles after their contactw ith biological fluids. [38i, 89] There is av ast literature on nanomedicine and nanomedical approaches (see, for example, [48a, 90] ), but here we will discuss only the applications of calcium phosphate nanoparticles.…”

The potential of nanoparticles for the immunization against viral infections

“…6). 9 We identified a clear correlation between the percentage of CD8 + effector T cells and the viral loads: more CD8 + effector T cells in the spleen were correlated with lower viral loads. This demonstrates that an immunization with antigen/adjuvantfunctionalized calcium phosphate nanoparticles is a very efficient method for the induction or reactivation of retrovirusspecific T cell responses, and that they represent a promising approach to improve antiretroviral vaccination.…”

“…[2][3][4][5][6][7][8] They can be prepared in various sizes and loaded with different (bio-)molecules, including targeting moieties like antibodies to specifically address different cell types. 9,10 This offers new possibilities because several cargo molecules (e.g. stimulatory molecules and antigen) can be delivered at the same time to the same cell, thereby provoking a fine-tuned immune response.…”

Delivery of the autofluorescent protein R-phycoerythrin by calcium phosphate nanoparticles into four different eukaryotic cell lines (HeLa, HEK293T, MG-63, MC3T3): Highly efficient, but leading to endolysosomal proteolysis in HeLa and MC3T3 cells

“…The delivery of therapeutic molecules with the help of nanoparticles is a major goal of nanomedicine [ 3 , 69 , 70 ]. In gene therapy, this is exploited for transfection and gene silencing [ 5 , 6 , 8 ], in immunology, it is used for vaccination and cell stimulation [ 71 – 73 ], and in tumour therapy, it is used to deliver therapeutic molecules like cytostatics [ 4 , 74 , 75 ]. Typically, a transport of these drugs across the cell membrane is desired, and the functional integrity of the drugs must be assured to preserve the therapeutic effect.…”