Delivery of novel coumarin-dihydropyrimidinone conjugates through mixed polymeric nanoparticles to potentiate therapeutic efficacy against triple-negative breast cancer.

To date, most of the accessible therapeutic options are virtually non-responsive towards triple-negative breast cancer (TNBC) due to its highly aggressive and metastatic nature. Interestingly, chemotherapy reacts soundly in many TNBC cases compared to other types of breast cancer. However, the side effects of many chemotherapeutic agents are still under cross-examination, and thus prohibit their extensive uses. In this present study, we have developed a series of coumarin-dihydropyrimidinone conjugates (CDHPs) and subsequently their poly(lactic-co-glycolic acid) (PLGA)-PEG4000 mixed copolymer nanoparticles as excellent chemotherapeutic nanomedicine to control TNBC. Among all the synthesized CDHPs, CDHP-4 (prepared by the combination of EDCO with 3,4-difluorobenzaldehyde) showed excellent therapeutic effect on a wide variety of cancer cell lines, including TNBC. Besides, it can control the metastasis and stemness property of TNBC. Furthermore, the nano-encapsulation of CDHP-4 in a mixed polymer nanoparticle system (CDHP-4@PP-NPs) and simultaneous delivery showed much improved therapeutic efficacy at a much lower dose, and almost negligible side effects in normal healthy cells or organs. The effectiveness of the present therapeutic agent was observed both in intravenous and oral mode of administration in in vivo experiments. Moreover, on elucidating the molecular mechanism, we found that CDHP-4@PP-NPs could exhibit apoptotic, anti-migratory, as well as anti-stemness activity against TNBC cell lines through the downregulation of miR-138. We validated our findings in MDA-MB-231 xenograft chick embryos, as well as in 4T1-induced mammary tumor-bearing BALB/c mice models, and studied the bio-distribution of CDHP-4@PP-NPs on the basis of the photoluminescence property of nanoparticles. Our recent study, hence for the first time, unravels the synthesis of CDHP-4@PP-NPs and the molecular mechanism behind the anti-migration, anti-stemness and anti-tumor efficacy of the nanoparticles against the TNBC cells through the miR-138/p65/TUSC2 axis.

Small-Molecule Probe for Sensing Serum Albumin with Consequential Self-Assembly as a Fluorescent Organic Nanoparticle for Bioimaging and Drug-Delivery Applications.

The recognition of a specific protein in blood serum amidst similar proteins is a challenging and vital endeavor in clinical diagnostics. Herein, we have described a small-molecule probe (DFPAC-OH) that can induce self-assembly of human serum albumin (HSA) and bovine serum albumin (BSA) to generate a highly sustainable fluorescent organic nanoparticle (NP), useful for imaging and in vitro drug-delivery applications. In the midst of similar proteins, DFPAC-OH selectively binds in a noncovalent manner to serum albumin. The specific binding tailors the fluorescence properties of DFPAC-OH. The lowest detection limit for BSA is 47 nM with a binding constant of 1.03 × 105 M-1. The probe can efficiently detect HSA in an artificial urine sample. Furthermore, the subsequent bovine albumin self-assembled nanoparticle (DFPAC-OH@BSA-NPs) displays a strong emission at 580 nm both in solution and in solid state. The nanoparticle is highly stable over a long pH range, covering the physiologic pH, and shows an excellent bioavailability to be used for sustainable cell imaging and drug-delivery applications. In addition, the cellular internalization and the pH-responsive drug-release behavior of a hydrophobic drug thymoquinone (TQ) encapsulated in DFPAC-OH@BSA-NPs (TQ-DFPAC-OH@BSA-NPs) have also been evaluated in A549 cell lines. The cytotoxic effect and quantification of intracellular reactive oxygen species (ROS) generation were further examined carefully to observe the anticancer property of TQ-DFPAC-OH@BSA-NPs. Therefore, the present system can simultaneously deliver drug molecules and image the event of delivery. The entire nanoparticles are characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), dynamic light scattering (DLS), and infrared (IR) spectroscopy. The specific binding of DFPAC-OH is well supported by the molecular docking study, fluorescence lifetime measurement, and circular dichroism analysis.

Colorimetric and fluorescence probe for the detection of nano-molar lysine in aqueous medium.

A single crystal X-ray structurally characterized BODIPY based probe, THBPY, derived from 4-hydroxy-5-isopropyl-2 methyl-isophthalaldehyde, detects nano-molar lysine in aqueous medium. In the presence of lysine, THBPY visibly changes its color and fluorescence profile due to the formation of a stable imine bond. A distinctive color change allows for facile discrimination over other amino acids in a wide range of concentrations of lysine. The detection limit for lysine is 0.001 µM by a fluorescence method and 0.01 µM by a colorimetric method. The probe shows good reversibility for multiple uses and cleanly discriminates between lysine and other amino acids. Density functional theoretical studies closely resemble experimental results.

Tailoring Ligand Environment toward Development of Colorimetric and Fluorescence Indicator for Biological Mn(II) Imaging.

Mn(2+) ion plays an essential role in all forms of life. Paramagnetic nature of Mn(2+) and its close resemblance with Ca(2+) and Mg(2+) are two key limiting factors responsible for the least development of fluorescence probes suitable for bioimaging. In literature we have found only a few Mn(2+) selective fluorescent sensor and their applications. These probes are mainly based on linear polydentate and macrocyclic ligands. Systematic tuning of ligand environment allows colorimetric and fluorescence recognition of traces Mn(2+) in real sample and fluorescence indicator in living RAW264.7 cells. Two probes, one based on fluorescein (FHDB) and the other based on rhodamine (RDDB) showed turn-on response toward Mn(2+) in DMSO and acetonitrile, respectively. Colorimetric detection of Mn(2+) ion is also possible in the presence of other metal ions. The new sensing probe RDDB shows higher sensitivity as well as faster response compared to the reported systems. The detection limit of RDDB is 5 × 10(-8) M and FHDB is 1 × 10(-7) M. DFT studies strongly support the experimental facts.

Sn(II) induced concentration dependent dynamic to static excimer conversion of a conjugated naphthalene derivative.

The X-ray structurally characterized naphthalene appended diformyl-p-cresol derivative () selectively detects Sn(2+) by both colorimetric and fluorescence methods. In the presence of Sn(2+), exhibits a monomer emission at 420 nm along with a strong red excimer emission at 582 nm in acetonitrile. The excimer formation highly depends on Sn(2+) concentration. The dynamic excimer, observed with up to 2.5 equivalents of Sn(2+), gradually converts to a static form above 2.5 equivalents of Sn(2+). Moreover, in a different solvent media, viz. in aqueous methanol, can also detect Al(3+) through the generation of intense green fluorescence. The photophysical interactions are rationalized by (1)H NMR, mass spectra, steady state and lifetime fluorescence measurements. DFT studies support the experimental findings.