Dextran nanoparticles

Other promising work describing DNA delivery with dextrans has been published recently from the Frechet laboratory [43]. Acetal-derivatized dextran was solvent evaporated to form dextran nanoparticles which are cleavable under acidic pH [44]. Exploiting the reducing chain ends present on the carbohydrate particles,... 

Chalasani, K.B. Russell-Jones, G.J. Jain, A.K. Diwan, P.V. Jain, S.K. Effective oral delivery of insulin in animal models using vitamin B12-coated dextran nanoparticles. 7. Contr. Release 2007,122 (2), 141-150. 

C. Ornelas-Megiatto, P. Shah, P. Wich, J. Cohen, J. Tagaev, J. Smolen, B. Wright, M. Panzner, W. Youngs, J. Frechet, C. Cannon, Aerosolized antimicrobial agents based on degradable dextran nanoparticles loaded with silver carbene complexes. Mol. Pharm. 9 (2012) 3012-3022. 

Due to its hydrophilic nature, dextrans have also been used to conjugate bioactive substances (e.g., dmgs, enzymes, hormones, and antibodies) to prolong circulation lifetimes, increase stability in vivo, or depress antigenicity. For example, dextran nanoparticles have been conjugated with insulin for oral delivery. These nanocarriers can protect insulin from degradation in the gut and modulate release profiles. ... 

Cui, L., Cohen, J.A., Broaders, K.E., Beaudette, T.T., Frechet, J.M. Mannosylated dextran nanoparticles a pH-sensitive system engineered for immunomodulation through mannose targeting. Bioconjug. Chem. 22, 949-957 (2011)... 

Dextran Nanoparticles Targeted delivery of cisplatin for breast cancer growth and metastasis [21]... 

Poly(DL-lactide- co-glycolide)-grafted dextran Nanoparticles To enhance antitumor effect of adriamycin [23]... 

Li M, Tang Z, Zhang Y, Lv S, Li Q, Chen X. Targeted delivery of cisplatin by LHRH-peptide conjugated dextran nanoparticles suppresses breast cancer growth and metastasis. Acta Biomater. 2015 18 132-43. 

In a different way, metallic-core nanoparticles [346-349] (prepared cf. Section 3.10) equipped with biocompatible coats such as L-cysteine or dextrane may be exploited for highly efficient and cell-specific cancer cell targeting, i.e., for improving diagnosis and therapy of human cancer. In a recent proof-of-principle experiment an unexpectedly low toxicity of the L-cysteine-covered cobalt nanoparticles was demonstrated [433] For diagnostic purposes, it is expected to use the advantageous magnetic properties of the metallic-core nanoparticles to obtain a contrast medium for MRI with considerably increased sensitivity, capable to detect micro-metastases in the environment of healthy tissues [434 37]. 

The branched polysaccharide dextran is assembled with alkanethiol-modified gold nanoparticles and the resulting nanocomposite is then functionalized to facilitate the specific binding of target biomolecules. This biorecognition process can be easily detected by particle plasmon resonance (PPR), based on the optical properties of gold nanoparticles [163]. 

In a reverse microemulsion, the hydrolysis and polymerization of the silicate precursor occur in the water droplet, therefore, to dope dyes in the silica nanoparticles they must be water soluble. However, a number of organic dye molecules are hydrophobic, requiring modifications prior to doping. Several methods are available to link a hydrophobic dye molecule to a water soluble group. A simple and effective example is to link a hydrophilic dextran to the dye molecules [8]. This modification can greatly enhance the water solubility of hydrophobic dye molecules, but will increase the cost of resultant DDSNs. 

For MRI or histological tracking of MSG in vivo, cultured mesenchymal stem cells were prelabeled for 24 hours with carboxy-dextran-coated iron oxide nanoparticles (Resovist, Schering, Berlin, Germany) (Ittrich et al, 2005 Lange et al., 2005b). 

For magnetite nanoparticles, Aco 3 x 10 s , so that the boundary corresponds to a radius of about 7 nm. When the magnetite cores are diluted in a dextran coating, the equatorial field of the agglomerated cluster is lower and our theoretical approach could remain valid for up to radii of approximately 50 nm. 

Microspheres and nanoparticles often consist of biocompatible polymers and belong either to the soluble or the particle type carriers. Besides the aforementioned HPMA polymeric backbone, carriers have also been prepared using dextrans, ficoll, sepharose or poly-L-lysine as the main carrier body. More recently alginate nanoparticles have been described for the targeting of antisense oligonucleotides [28]. As with other polymeric carrier systems, the backbone can be modified with e.g. sugar molecules or antibody fragments to introduce cellular specificity. 

Jain et al. (33) used the microemulsion system Triton X-100/cyclo-hexane/hexanol/water/ammonia to prepare silica nanoparticles with entrapped bioactive macromolecules fluorescein isothiocyanate-dextran (FITC-Dx) (mol. mass 19.6 kD), [125I]tyraminylinulin (mol. mass 5 kD), and horseradish peroxidase (HRP) (mol. mass 40 kD). The biomolecules were first solubilized in the microemulsion, and the alkoxide (TMOS) was then added. To ensure small particle sizes, the reaction was conducted under ice-cold temperatures (in a refrigerator for 72 h). 

FIGURE 20.8 A particle of dextran as a product of an atmospheric spray-freeze drying process. (From Leuenberger, HJ. Nanoparticle Res., 4, 111-119 (2002c).)... 

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