Microfluidic synthesis of curcumin loaded polymer nanoparticles with tunable drug loading and pH-triggered release.

Polymer nanoparticles (NPs) have attracted significant interest in the past years for drug delivery and triggered release. However, it remains a significant challenge to produce polymer NPs with controlled properties and tunable drug loading. Traditional nanoprecipitation often leads to low drug loading. This study reports the development of a new microfluidic nanoprecipitation approach for making polymer NPs with tunable drug loading up to 50%. The synthesized curcumin-loaded shellac NPs remain very stable for the period of our experiments (10 days) under acidic conditions (pH 4.5), but release the payload at neutral pH in a sustained manner. This work provides a new strategy for making drug-loaded polymer NPs with tunable drug loading and triggered release.

RGD functionalized chitosan nanoparticle mediated targeted delivery of raloxifene selectively suppresses angiogenesis and tumor growth in breast cancer.

Acidic pH is a crucial intrinsic property of the microenvironment of most solid tumors. Hence, the use of pH sensitive tumor targeting nanoparticles is an attractive approach to enhance the therapeutic efficacy of anti-cancer agents in solid tumors. Chitosan nanoparticles (CHNPs) have been widely explored in the area of cancer drug delivery; nevertheless their true potential as a pH responsive targeted drug delivery vehicle in cancer therapy has not been deciphered yet as most of the research is limited to pH dependent stability and drug release. In the present study, we investigate the direct effect of pH in synergy with RGD peptide based targeting on the therapeutic efficacy of chitosan nanoparticles (RGD-CHNPs) in breast cancer. Furthermore, for the first time we performed a comprehensive study showing the anti-tumor, anti-migratory and anti-angiogenic effect of raloxifene (Rlx) loaded CHNPs in breast cancer. We prepared stable formulations of raloxifene encapsulated CHNPs and RGD-CHNPs by the nontoxic ionic gelation method. pH dependent studies revealed that NPs possess higher stability and zeta potential along with enhanced cellular uptake at acidic pH (as present in solid tumors) compared to physiological pH. Furthermore, RGD conjugation enhanced the in vitro cellular uptake of CHNPs in αvß3 integrin expressing breast cancer cells and induced higher cellular apoptosis in breast cancer cells which was further augmented by lower pH. Moreover, Rlx-RGD-CHNPs significantly inhibited breast cancer cell migration and angiogenesis. In vivo studies showed that Cy5.5 conjugated RGD-CHNPs can distinctly visualize tumors and Rlx-RGD-CHNPs significantly inhibit breast tumor growth without causing any toxic effect to normal tissue as confirmed by hematology and blood biochemical studies. Therefore, RGD-CHNPs could potentially enhance the therapeutic efficacy of chemotherapeutic drugs due to the synergistic effect of pH responsiveness and tumor specific targeting in breast cancer.

Multi Drug Loaded Thermo-Responsive Fibrinogen-graft-Poly(N-vinyl Caprolactam) Nanogels for Breast Cancer Drug Delivery.

This study aims at the targeted delivery of 5-fluorouracil (5-FU) and Megestrol acetate (Meg) loaded fibrinogen-graft-poly(N-Vinyl caprolactam) nanogels (5-FU/Meg-fib-graft-PNVCL NGs) toward α5ß1-integrins receptors expressed on breast cancer cells to have enhanced anti-cancer effect in vitro. To achieve this aim, we developed biocompatible thermoresponsive fib-graft-PNVCL NGs using fibrinogen and carboxyl terminated PNVCL via EDC/NHS amidation reaction. The Lower Critical Solution Temperature (LCST) of fib-graft-PNVCL could be tuned according to PNVCL/fibrinogen compositions. The 100-120 nm sized nanogels of fib-graft-PNVCL (LCST = 35 ?1 'C) was prepared using CaCl2 cross-linker. The 5-FU/Meg-fib-graft-PNVCL NGs showed a particle size of 150-170 nm size. The drug loading efficiency with 5-FU was 62% while Meg showed 74%. The 5-FU and Meg release was prominent above LCST than below LCST. The multi drug loaded fib-graft-PNVCL NGs showed enhanced toxicity, apoptosis and uptake by breast cancer (MCF-7) cells compared to their individual doses above their LCST. The in vivo assessment in Swiss albino mice showed sustained release of Meg and 5-FU as early as 3 days, confirming the therapeutic efficiency of the formulation. These results demonstrate an enhanced platform for the future animal studies on breast tumor xenograft model.

Dual drug encapsulated thermo-sensitive fibrinogen-graft-poly (N-isopropyl acrylamide) nanogels for breast cancer therapy.

5-FU/Megestrol acetate loaded fibrinogen-graft-PNIPAAm Nanogels (5-FU/Meg-fib-graft-PNIPAAm NGs) were prepared for thermo responsive drug delivery toward α5ß1-integrins expressing breast cancer cells in vitro (MCF-7 cells). The 60-100 nm sized fib-graft-PNIPAAm nanogels (LCST=35 °C) were prepared by CaCl2 cross-linker. 5-FU/Meg-fib-graft-PNIPAAm NGs showed particle size of 165-195 nm size. The drug loading efficiency with 5-FU was 60% and 70% for Meg. "Drug release was greater above the lower critical solution temperature (LCST). Above LCST, drug release system triggers apopotosis and enhance toxicity to MCF-7 cells when compared to the equivalent dose of the free drug. This effect was due to the greater uptake of the drug by MCF-7 cells". 5-FU/Meg-fib-graft-PNIPAAm NGs is portrayed here as a new combinatorial thermo-responsive drug delivery agent for breast cancer therapy.

Paclitaxel loaded fibrinogen coated CdTe/ZnTe core shell nanoparticles for targeted imaging and drug delivery to breast cancer cells.

The study aims at the targeted imaging using CdTe/ZnTe core shell QDs and delivery of paclitaxel (PTX) loaded fibrinogen coated yellow-QDs (PTX-fib-yellow-QDs) towards breast cancer cells via the alpha5Beta1-integrins. We developed fibrinogen coated different sized CdTe/ZnTe core shell quantum dots of 2-10 nm size, which have been prepared by one-pot aqueous-phase approach. The fib-coated-QDs (fib-coated-QDs) and PTX-fib-yellow-QDs were prepared by two-step coacervation technique using CaCl2 as cross-linker. Particle size of fib-coated-QDs was in between 60-220 nm while PTX-fib-yellow-QDs showed 180 +/- 40 nm. The MTT assay confirmed cytocompatibility of fib-coated-QDs on L929 and MCF-7 than bare QDs, whereas significant toxicity toward MCF-7 by PTX-fib-yellow-QDs was observed. The hemocompatible fib-coated-QDs showed enhanced localization and retention toward alpha5beta1-integrins +ve MCF-7 compared to alpha5beta1-integrins -ve L929 cells. The specific binding of fib-coated-yellow-QDs was further confirmed with alpha5beta1-integrins +ve HeLa and alpha5/beta1-integrins -ve HT29 cells. Cellular uptake studies revealed localization of PTX-fib-coated-yellow-QDs inside MCF-7 cells compared to the normal L929 cells. These results indicated that fib-coated-QDs could be used for targeted imaging and as a suitable "nanocarrier" aiming breast cancer cells.