The
development of drug delivery systems using nanoparticles as
carriers for small and large therapeutic molecules remains a rapidly
growing area of research. The advantages of using proteins to prepare
nanoparticles for drug delivery applications include their abundance
in natural sources, biocompatibility, biodegradability, easy synthesis
process, and cost-effectiveness. In contrast to several particulate
systems like nanoparticles from metallic and inorganic/synthetic sources,
the protein nanoparticles do not have limitations such as potential
toxicity, large size, accumulation, or rapid clearance from the body.
In addition, protein-based nanoparticles offer the opportunity for
surface modification by conjugation of other protein and carbohydrate
ligands. This enables targeted delivery to the desired tissue and
organ, which further reduces systemic toxicity. The use of protein
nanoparticles for such applications could therefore prove to be a
better alternative to maneuver and improve the pharmacokinetic and
pharmacodynamic properties of the various types of drug molecules.
In this review, while focusing on the properties of a few proteins
such as the silk protein fibroin, we attempt to provide an overview
of the existing protein-based nanoparticles. We discuss various methods
for the synthesis of this class of nanoparticles. The review brings
forth some of the factors that are important for the design of this
class of nanoparticles and highlights the applications of the nanoparticles
obtained from these proteins.
This study involves the photocatalytic degradation of Reactive Black 5 (RB5) and Reactive Orange 4 (RO4) dyes, employing heterogeneous photocatalytic process. Photocatalytic activity of different semiconductors such as titanium dioxide (TiO2) and zinc oxide (ZnO) has been investigated. An attempt has been made to study the effect of process parameters through amount of catalyst, concentration of dye, and pH on photocatalytic degradation of RB5 and RO4. The experiments were carried out by varying pH (3–11), amount of catalyst (0.25–1.5 g/L), and initial concentration of dye (10–100 mg/L). The optimum catalyst dose was found to be 1.25 and 1 g/L for RB5 and RO4, respectively. In the case of RB5, maximum rate of decolorization was observed in acidic medium at pH 4, whereas the decolorization of RO4 reached maximum in basic region at pH 11. The performance of photocatalytic system employing ZnO/UV light was observed to be better than TiO2/UV system. The complete decolorization of RB5 was observed after 7 min with ZnO, whereas with TiO2, only 75% dye degraded in 7 min. In the case of RO4, 92 and 62% decolorization was noticed in the same duration.
Glycosyl triazoles
are conveniently accessible and contain multiple
metal-binding units that may assist in metal-mediated catalysis. Azide
derivatives of d-glucose have been converted to their respective
aryltriazoles and screened as ligands for the synthesis of 2-substituted
benz-fused azoles and benzimidazoquinazolinones by Cu-catalyzed intramolecular
Ullmann type C-heteroatom coupling. Good to excellent yields for a
variety of benz-fused heterocyles were obtained for this readily accessible
catalytic system.
Red blood cells (RBCs) from 24 patients with sickle cell disease were more adherent to cultured endothelium pretreated with the inflammatory cytokine, tumour necrosis factor (TNF) than RBCs from 22 healthy subjects. The enhanced sticking was apparent in RBC preparations from patients who were in crisis (mean 190% increase from controls) and out of crisis (mean 220% increase) and was not related to the number of circulating RBCs, reticulocytes, platelets, leucocytes or haemoglobin levels. When irreversibly sickled RBCs, enriched by centrifugation on density gradients, were added to TNF-treated endothelium they were found to be significantly more adherent (mean 411% increase; P < 0.001) than the unfractionated RBCs from the same patients. There was no difference between the adherent properties of sickle RBCs and normal RBCs for untreated endothelium. Contributing factors to the enhanced adhesion to TNF-treated endothelium may be the low surface change of sickle RBCs, and increased levels of fibrinogen and von Willebrand's factor (vWF) in the patients' plasma. By acting on vascular endothelium to increase its adhesiveness for sickled RBCs, it is concluded that inflammatory cytokines such as TNF may have a prominent role in mediating the events that lead to microvascular occlusions in sickle cell disease.
Glycosyl triazoles have been introduced
as efficient ligands for
the Cu-catalyzed Sonogashira reaction to overcome the challenges of
sideways homocoupling reactions in Cu catalysis in this reaction.
The atmospheric oxygen in a sealed tube did not affect the coupling,
and no need of complete exclusion of oxygen was experienced in the
presence of glycohybrid triazole ligand L3. High product
yields were obtained at 130 °C for a variety of substrates including
aliphatic and aromatic terminal alkynes and differently substituted
aromatic halides including 9-bromo noscapine. In contrast, at room
temperature, a very low loading of the L3-Cu catalytic
system could produce excellent yields in Glaser coupling including
homocoupling and heterocoupling of a variety of aliphatic and aromatic
alkynes.
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