Generation of Ag Nanoparticles by PAMAM Dendrimers and their Size Dependence on the Aggregation Behavior of Dendrimers

Stable silver nanoparticles were generated in aqueous medium by amine, hydroxy and carboxylate terminated poly(amidoamine) (PAMAM) dendrimers in the absence of conventional reducing agents and light irradiation. Mechanistic studies suggest that, in spite of their lower pK_a values, tertiary amines present in the dendritic structures act as the reducing agent. Dynamic light scattering and electron microscopic studies reveal that PAMAM dendrimers aggregate in presence of silver ions and the aggregation propensity plays a pivotal role in altering the size and shape of the nanoparticles generated in the dendritic milieu. The formation of metal nanoparticles with uniform size and shape by amine terminated PAMAM dendrimer is attributed to the unique aggregation propensity of amine terminated PAMAM.

     

Aquaporin-1 in breast cancer

The canonical function of aquaporin (AQP) water channels is to facilitate passive transport of water across cellular membranes making them essential in the regulation of body water homeostasis. Moreover, AQPs, including AQP1, have been found to be overexpressed in multiple cancer types, including breast cancer, where AQP1 overexpression is associated with poor prognosis. AQPs have been shown to affect cellular processes associated with cancer progression and spread including cell migration, angiogenesis, and proliferation. Moreover, AQPs can regulate levels of adhesion proteins at cell–cell junctions, a regulatory role, which is still largely unexplored in cancer. Understanding the molecular mechanisms of how AQP1 contributes to breast cancer progression and metastatic processes is essential to establish AQP1 as a biomarker and to develop targeted anticancer treatments for breast cancer patients. This mini-review focuses on the role of AQP1 in breast cancer.     

5FU encapsulated polyglycerol sebacate nanoparticles as anti-cancer drug carriers

The majority of anti-cancer drugs fail to reach clinical trials due to their low water solubility. A biocompatible drug delivery system that encapsulates and efficiently delivers hydrophobic drugs to the target site is the need of the hour. This study addresses the issue by focusing on a polymeric polyglycerol sebacate (PGS) nanoparticles loaded with 5-fluorouracil (5FU), a primary line chemotherapy drug for many types of cancers. The generated nanoparticle (PGS-NP) was biocompatible and had minimal cytotoxicity against the MDA-MB-231 and A549 cell lines, even at a high concentration of 100 μg mL⁻¹. The cell viability post treatment with PGS nanoparticles encapsulated with 5FU (PGS-5FU) decreased to as low as around 40% whereas, in the case of treatment with 5FU, the viability percentage increased. The nanoparticles also showed controlled drug release when encapsulated with 5FU. This striking observation suggested that these nanoparticles can improve the efficacy of drug delivery to tumor sites. Apoptosis assay and caspase-3 activity quantification supported these data wherein PGS-5FU treatment showed almost three times caspase-3 activity as compared to control cells. Additionally, throughout all the experiments, MDA-MB-231 cells were more sensitive to PGS-5FU than A549 cells, indicating that these nanoparticles are ideal for breast cancer treatment. In summary, 5FU encapsulated PGS nanoparticles are a potential drug carrier to deliver 5FU efficiently to cancer cells.

Diagrammatic flowchart for the synthesis of polymeric PGS and preparation of 5FU-loaded PGS nanoparticles.