Search results for "Nanocarriers"
showing 10 items of 145 documents
Brush Conformation of Polyethylene Glycol Determines the Stealth Effect of Nanocarriers in the Low Protein Adsorption Regime
2021
For nanocarriers with low protein affinity, we show that the interaction of nanocarriers with cells is mainly affected by the density, the molecular weight, and the conformation of polyethylene glycol (PEG) chains bound to the nanocarrier surface. We achieve a reduction of nonspecific uptake of ovalbumin nanocarriers by dendritic cells using densely packed PEG chains with a "brush" conformation instead of the collapsed "mushroom" conformation. We also control to a minor extent the dysopsonin adsorption by tailoring the conformation of attached PEG on the nanocarriers. The brush conformation of PEG leads to a stealth behavior of the nanocarriers with inhibited uptake by phagocytic cells, whi…
Heparin modulates the cellular uptake of nanomedicines
2021
Liposomal formulations are used to improve the safety and cellular absorption of conventional drugs by limiting their interaction with phagocytes. The uptake behaviour of these nanocarriers is affected by the blood composition, and accordingly the presence of an anticoagulant in the blood could have a critical impact on the efficiency of nanomedicines. For the negatively charged liposomes, such as AmBisome®, no significant change in the uptake could be observed when co-incubated with heparin and primary phagocytes. Yet, we observed that a peak of the uptake extent of cationic liposomes was reached at a clinically relevant concentration of heparin for phagocytes and cancer cells. Hence, we r…
Noncovalent Targeting of Nanocarriers to Immune Cells with Polyphosphoester‐Based Surfactants in Human Blood Plasma
2019
Abstract Dendritic cells (DCs) are part of the immune system and can internalize pathogens by carbohydrate receptors. The uptake induces maturation and migration of the DCs resulting in an adaptive immune response by presenting antigens to T‐cells. Thus, targeted delivery to DCs is a powerful tool for immunotherapy. However, in blood, specific targeting is challenging as blood proteins adsorb to the nanocarriers and mask the targeting molecules. Additionally, covalent coupling of targeting groups to nanocarriers requires new chemistry for each nanocarrier, while a general strategy is missing. A general protocol by noncovalent adsorption of mannosylated polyphosphoesters (PPEs) on the nanoca…
Bio-orthogonal triazolinedione (TAD) crosslinked protein nanocapsules affect protein adsorption and cell interaction
2020
Albumin-based protein nanocarriers have been widely exploited as drug delivery systems, since they show excellent degradability, low toxicity, but at the same time provide high loading capacity and relevant uptake into cells. For the formation of protein nanocapsules, bio-orthogonal reactions are important so that the material to be encapsulated is not affected by the shell formation. We show that protein nanocapsules with narrow size distributions and low protein adsorption upon contact with blood serum can be synthesized by inverse miniemulsion and interfacial crosslinking of the protein using triazolinediones (TADs) as powerful dienophiles and enophiles, which smoothly perform electrophi…
How Low Can You Go? Low Densities of Poly(ethylene glycol) Surfactants Attract Stealth Proteins.
2018
It is now well-established that the surface chemistry and “stealth” surface functionalities such as poly(ethylene glycol) (PEG) chains of nanocarriers play an important role to decrease unspecific protein adsorption of opsonizing proteins, to increase the enrichment of specific stealth proteins, and to prolong the circulation times of the nanocarriers. At the same time, PEG chains are used to provide colloidal stability for the nanoparticles. However, it is not clear how the chain length and density influence the unspecific and specific protein adsorption keeping at the same time the stability of the nanoparticles in a biological environment. Therefore, this study aims at characterizing the…
Nose-to-brain delivery of insulin enhanced by a nanogel carrier.
2018
Recent evidences suggest that insulin delivery to the brain can be an important pharmacological therapy for some neurodegenerative pathologies, including Alzheimer disease (AD). Due to the presence of the Blood Brain Barrier, a suitable carrier and an appropriate route of administration are required to increase the efficacy and safety of the treatment. Here, poly(N-vinyl pyrrolidone)-based nanogels (NG), synthetized by e-beam irradiation, alone and with covalently attached insulin (NG-In) were characterized for biocompatibility and brain delivery features in a mouse model. Preliminarily, the biodistribution of the "empty" nanocarrier after intraperitoneal (i.p.) injection was investigated b…
Smart copolymer coated SPIONs for colon cancer chemotherapy
2019
Human colon cancer is one of the higher aggressive solid tumors, whose high mortality, much like many other solid tumors, results from metastasis formation. To reduce this high mortality, more effective chemotherapy, allowing a specific tumor accumulation and an efficient early-stage medical imaging as well, are still needed. At this regard, stimuli-responsive nanocarriers for anticancer drug delivery are promising strategy in cancer therapy. For this purpose, a dual targeted redox-responsive drug delivery system, prepared by coating superparamagnetic nanoparticles (SPIONs) with the amphiphilic copolymer INU-LA-PEG-FA and loading doxorubicin (DOXO-SPIONs) was investigated as tool for solid …
Polymeric Nanocarriers for Magnetic Targeted Drug Delivery: Preparation, Characterization, and in Vitro and in Vivo Evaluation
2013
In this paper the preparation of magnetic nano- carriers (MNCs), containing superparamagnetic domains, is reported, useful as potential magnetically targeted drug delivery systems. The preparation of MNCs was performed by using the PHEA-IB-p(BMA) graft copolymer as coating material through the homogenization−solvent evaporation method. Magnetic and nonmagnetic nanocarriers containing flutamide (FLU-MNCs) were prepared. The prepared nanocarriers have been exhaustively characterized by dynamic light scattering (DLS), transmission electron microscopy (TEM), and magnetic measurements. Biological evaluation was performed by in vitro cytotoxicity and cell uptake tests and in vivo biodistribution …
Nanoemulsions for synthesis of biomedical nanocarriers
2021
Nanoemulsions are kinetically stabilized emulsions with droplet sizes in the nanometer scale. These nanodroplets are able to confine spaces in which reactions of polymerization or precipitation can take place, leading to the formation of particles and capsules that can act as nanocarriers for biomedical applications. This review discusses the different possibilities of using nanoemulsions for preparing biomedical nanocarriers. According to the chemical nature, nanocarriers prepared in nanoemulsions are classified in polymeric, inorganic, or hybrid. The main synthetic strategies for each type are revised, including miniemulsion polymerization, nanoemulsion-solvent evaporation, spontaneous em…
Chitosan-coated mesoporous MIL-100(Fe) nanoparticles as improved bio-compatible oral nanocarriers
2017
Nanometric biocompatible Metal-Organic Frameworks (nanoMOFs) are promising candidates for drug delivery. Up to now, most studies have targeted the intravenous route, related to pain and severe complications; whereas nanoMOFs for oral administration, a commonly used non-invasive and simpler route, remains however unexplored. We propose here the biofriendly preparation of a suitable oral nanocarrier based on the benchmarked biocompatible mesoporous iron(III) trimesate nanoparticles coated with the bioadhesive polysaccharide chitosan (CS). This method does not hamper the textural/structural properties and the sorption/release abilities of the nanoMOFs upon surface engineering. The interaction …