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Nanotechnology-based medical approaches have made tremendous potential for enhancing the treatment efficacy with minimal doses of chemotherapeutic drugs against cancer. In this study, using tamoxifen (Tam), biodegradable antibody conjugated polymeric nanoparticles (NPs) was developed to achieve targeted delivery as well as sustained release of the drug against breast cancer cells. Poly(D,L-lactic-co-glycolic acid) (PLGA) NPs were stabilized by coating with poly(vinyl alcohol) (PVA), and copolymer polyvinyl-pyrrolidone (PVP) was used to conjugate herceptin (antibody) with PLGA NPs for promoting the site-specific intracellular delivery of Tam against HER2 receptor overexpressed breast cancer (MCF-7) cells. The Tam-loaded PVP-PLGA NPs and herceptin-conjugated Tam-loaded PVP-PLGA NPs were characterized in terms of morphology, size, surface charge, and structural chemistry by dynamic light scattering (DLS), Transmission electron microscopy (TEM), ζ potential analysis, 1H nuclear magnetic resonance (NMR), and Fourier transform infrared (FT-IR) spectroscopy. pH-based drug release property and the anticancer activity (in vitro and in vivo models) of the herceptin conjugated polymeric NPs were evaluated by flow cytometry and confocal image analysis. Besides, the extent of cellular uptake of drug via HER2 receptor-mediated endocytosis by herceptin-conjugated Tam-loaded PVP-PLGA NPs was examined. Furthermore, the possible signaling pathway of apoptotic induction in MCF-7 cells was explored by Western blotting, and it was demonstrated that drug-loaded PLGA NPs were capable of inducing apoptosis in a caspase-dependent manner. Hence, this nanocarrier drug delivery system (DDS) not only actively targets a multidrug-resistance (MDR) associated phenotype (HER2 receptor overexpression) but also improves therapeutic efficiency by enhancing the cancer cell targeted delivery and sustained release of therapeutic agents.

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Combination therapy of multiple drugs through a single system is exhibiting high therapeutic effects. We investigate nanocarrier mediated inhibitory effects of topotecan (TPT) and quercetin (QT) on triple negative breast cancer (TNBC) (MDA-MB-231) and multi drug resistant (MDR) type breast cancer cells (MCF-7) with respect to cellular uptake efficiency and therapeutic mechanisms as in vitro and in vivo. The synthesized mesoporous silica nanoparticle (MSN) pores used for loading TPT; the outer of the nanoparticles was decorated with poly (acrylic acid) (PAA)-Chitosan (CS) as anionic inner-cationic outer layer respectively and conjugated with QT. Subsequently, grafting of arginine-glycine-aspartic acid (cRGD) peptide on the surface of nanocarrier (CPMSN) thwarted the uptake by normal cells, but facilitated their uptake in cancer cells through integrin receptor mediated endocytosis and the dissociation of nanocarriers due to the ability to degrade of CS and PAA in acidic pH, which enhance the intracellular release of drugs. Subsequently, the released drugs induce remarkable molecular activation as well as structural changes in tumor cell endoplasmic reticulum, nucleus and mitochondria that can trigger cell death. The valuable CPMSNs may open up new avenues in developing targeted therapeutic strategies to treat cancer through serving as an effective drug delivery podium.

Well-dispersed polyaniline (PANi) nanoparticles were successfully synthesized by simple oxidative polymerization of aniline in a two-phase system in the presence of poly­(vinylpyrrolidone) (PVP) as a polymer shell agent, and citric acid was used as a doping acid instead of inorganic acids due to its better biocompatibility. TEM showed that the nanocomposites of PANi and PVP (PANi@PVP) assembled into core–shell like nanostructures uniformly. MTT results indicated that the PANi@PVP nanoparticles supported the survival of cells; IC50 could reach about 2.5 mg/mL, much higher than the IC50 value reported for PANi nanoparticles without PVP. Furthermore, in the presence of PVP, only exceeding PANi (>1.5 mg/mL) resulted in a comparable production of intracellular reactive oxygen species (ROS), the induction of apoptosis in PC-12 cells, and a weaker DNA fragmentation. TEM of PC-12 cell sections displayed that the cell morphological changes associated with the apoptosis were induced when exposed to a very high dose of PANi@PVP (3 mg/mL). The well-dispersed PANi@PVP combined with NIR irradiation achieved excellent photothermal conversion performance, which could kill cancer cell BEL-7402 in vitro effectively. Reflecting this well-dispersed property, the tumors in cancer bearing KM mice disappeared thoroughly after a single subcutaneous injection of PANi@PVP nanoparticles and subsequent NIR laser irradiation.

Multifunctional magnetic polymer nanocombinations are gaining importance in cancer nanotheranostics due to their safety and their potential in delivering targeted functions. Herein, we report a novel multifunctional core-shell magnetic polymer therapeutic nanocomposites (NCs) exhibiting pH dependent "Off-On" release of drug against breast cancer cells. The NCs are intact in blood circulation ("Off" state), i.e., at physiological pH, whereas activated ("On" state) at intracellular acidic pH environment of the targeted breast cancer cells. The NCs are prepared by coating the cannonball (iron nanocore) with hydrophobic nanopockets of pH-responsive poly(d,l-lactic-co-glycolic acid) (PLGA) polymer nanoshell that allows efficient loading of therapeutics. Further, the nanocore-polymer shell is stabilized by poly(vinylpyrrolidone) (PVP) and functionalized with a targeting HER2 ligand. The prepared Her-Fe3O4@PLGA-PVP nanocomposites facilitate packing of anticancer drug (Tamoxifen) without premature release in the bloodstream, recognizing the target cells through binding of Herceptin antibody to HER2, a cell surface receptor expressed by breast cancer cells to promote HER2 receptor mediated endocytosis and finally releasing the drug at the intracellular site of tumor cells ("On" state) to induce apoptosis. The therapeutic efficiency of hemo/cytocompatible NCs drug delivery system (DDS) in terms of targeted delivery and sustained release of therapeutic agent against breast cancer cells was substantiated by in vitro and in vivo studies. The multifunctional properties of Her-Tam-Fe3O4@PLGA-PVP NCs may open up new avenues in cancer therapy through overcoming the limitations of conventional cancer therapy.

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Nanotechnology is a branch of science dealing with the developing processes of a new type of nanomaterials by several methods. In the biomedical field, nanotechnology is widely used in the...