Biplob Koch

DNA Binding and Anti-Cancer Activity of Redox-Active Heteroleptic Piano-Stool Ru(II), Rh(III), and Ir(III) Complexes Containing 4-(2-Methoxypyridyl)phenyldipyrromethene

The synthesis of four novel heteroleptic dipyrrinato complexes [(η(6)-arene)RuCl(2-pcdpm)] (η(6)-arene = C6H6, 1; C10H14, 2) and [(η(5)-C5Me5)MCl(2-pcdpm)] (M = Rh, 3; Ir, 4) containing a new chelating ligand 4-(2-methoxypyridyl)-phenyldipyrromethene (2-pcdpm) have been described. The complexes 1-4 have been fully characterized by various physicochemical techniques, namely, elemental analyses, spectral (ESI-MS, IR, (1)H, (13)C NMR, UV/vis) and electrochemical studies (cyclic voltammetry (CV) and differential pulse voltammetry (DPV)). Structures of 3 and 4 have been determined crystallographically. In vitro antiproliferative and cytotoxic activity of these complexes has been evaluated by trypan blue exclusion assay, cell morphology, apoptosis, acridine orange/ethidium bromide (AO/EtBr) fluorescence staining, and DNA fragmentation assay in Dalton lymphoma (DL) cell lines. Interaction of 1-4 with calf thymus DNA (CT DNA) has also been supported by absorption titration and electrochemical studies. Our results suggest that in vitro antitumor activity of 1-4 lies in the order 2 > 1 > 4 > 3.

DNA/Protein Binding, Molecular Docking, and in Vitro Anticancer Activity of Some Thioether-Dipyrrinato Complexes

Syntheses and characterizations of the arene ruthenium [(η(6)-C6H6)RuCl(4-mtdpm)] (1), [(η(6)-p-MeC6H4Pr(i))RuCl(4-mtdpm)] (2), and structurally analogous rhodium/iridium complexes [(η(5)-C5Me5)RhCl(4-mtdpm)] (3) and [(η(5)-C5Me5)IrCl(4-mtdpm)] (4) [4-mtdpm = 5-(4-methylthiophenyl)dipyrromethene] have been reported. Their identities have been established by satisfactory elemental analyses, electrospray ionization-mass spectrometry (ESI-MS), FT-IR, NMR ((1)H, (13)C), UV/vis, emission spectral, and electrochemical studies. Structure of the representative complex 3 has been authenticated by X-ray single crystal analyses. The complexes 1-4 effectively bind with calf thymus DNA (CT DNA) through intercalative/electrostatic interactions. In addition, these exhibit significant cytotoxicity toward Dalton lymphoma (DL) cell line and cause static quenching of the bovine serum albumin (BSA) fluorophore. The antiproliferative activity, morphological changes, and apoptosis have been evaluated by MTT assay, acridine orange/ethidium bromide (AO/EtBr) fluorescence staining, and DNA ladder assay. Mode of interaction of the complexes with DNA/protein has also been supported by molecular docking. Various studies revealed remarkable decrease in the in vitro DL cell proliferation and induction of the apoptosis by 1-4, which lies in the order 2 > 1 > 4 > 3.

Interaction of ferrocene appended Ru(II), Rh(III) and Ir(III) dipyrrinato complexes with DNA/protein, molecular docking and antitumor activity

Efficacy of the ferrocene appended piano-stool dipyrrinato complexes [(η(6)-C6H6)RuCl(fcdpm)] (1), [(η(6)-C10H14)RuCl(fcdpm)] (2), [(η(6)-C12H18)RuCl(fcdpm)] (3) [(η(5)-C5Me5)RhCl(fcdpm)] (4) and [(η(5)-C5Me5)IrCl(fcdpm)] (5) [fcdpm = 5-ferrocenyldipyrromethene] toward anticancer activity have been described. Binding of the complexes with calf thymus DNA (CT-DNA) and BSA (bovine serum albumin) have been thoroughly investigated by UV-Vis and fluorescence spectroscopy. Binding constants for 1-5 (range, 10(4)-10(5) M(-1)) validated their efficient binding with CT-DNA. Molecular docking studies revealed interaction through minor groove of the DNA, on the other hand these also interact through hydrophobic residues of the protein, particularly cavity in the subdomain IIA. In vitro anticancer activity have been scrutinized by MTT assay, acridine orange/ethidium bromide (AO/EtBr) fluorescence staining, and DNA ladder (fragmentation) assay against Daltons Lymphoma (DL) cells. Present study revealed that rhodium complex (4) is more effective relative to ruthenium (1-3) and iridium (5) complexes.

Enhanced Red Upconversion Emission, Magnetoluminescent Behavior, and Bioimaging Application of NaSc0.75Er0.02Yb0.18Gd0.05F4@AuNPs Nanoparticles

The present study reports significant enhancement in the red upconversion emission of Er(3+) in NaSc0.8Er0.02Yb0.18F4 upconversion nanoparticles (UCNPs), via a two step process, (i) codoping of Gd(3+) ion at Sc(3+) site and (ii) attaching gold nanoparticles (AuNPs) at the surface of these codoped nanostructures, and further probes the use of these Gd:UCNPs@AuNPs for bioimaging application. The Gd(3+) codoping tailors the particle size (reduces) of UCNPs and bring out Er(3+)-Yb(3+) ion pair in close proximity, which promotes the cross relaxation mechanism and boosts the population in red emitting level (4)F9/2. Further, attachment of AuNPs on the surface of UCNPs gives 2-fold advantages, that is, reduction in green band (through resonance energy transfer with efficiency 31.54%) and enhancement in red band (through plasmonic effect). It gives red to green (R/G) ratio nearly 20:1 (almost single band red UC), which is quite promising for imaging application. In addition to this, codoping of Gd(3+) enhances the magnetic moment appreciably and the obtained magnetic moment for NaSc0.75Er0.02Yb0.18Gd0.05F4 UCNPs (∼1.7 emu/g) is close to the reported values for bioseparation in case of NPs. This shows the potential of the material for multimodal (optical and magnetic both) imaging application. These magnetoluminescence particles were found safe up to 1 mg/mL dose as assessed by cytotoxicity measurement in human cervical cancer (HeLa) and lung cancer (A549) cells. Ultrafine nanoparticles, transparent, and stable colloidal solution and the unique red UC emission endow these NPs as optical probe for imaging applications.

Effects of transferrin conjugated multi-walled carbon nanotubes in lung cancer delivery

The aim of this study was to develop multi-walled carbon nanotubes (MWCNT) which were covalently conjugated with transferrin by carbodiimide chemistry and loaded with docetaxel as a model drug for effective treatment of lung cancer in comparison with the commercial docetaxel injection (Docel™). d-Alpha-tocopheryl polyethylene glycol 1000 succinate (TPGS) was used as amphiphilic surfactant to improve the aqueous dispersity and biocompatibility of MWCNT. Human lung cancer cells (A549 cells) were employed as an in-vitro model to access cellular uptake, cytotoxicity, cellular apoptosis, cell cycle analysis, and reactive oxygen species (ROS) of the docetaxel/coumarin-6 loaded MWCNT. The cellular uptake results of transferrin conjugated MWCNT showed higher efficiency in comparison with free C6. The IC50 values demonstrated that the transferrin conjugated MWCNT could be 136-fold more efficient than Docel™ after 24h treatment with the A549 cells. Flow cytometry analysis confirmed that cancerous cells appeared significantly (P<0.05) in the sub-G1 phase for transferrin conjugated MWCNT in comparison with Docel™. Results of transferrin conjugated MWCNT have showed better efficacy with safety than Docel™.

Potential apoptosis inducing agents based on a new benzimidazole schiff base ligand and its dicopper(II) complex

Synthesis, characterization and antiproliferative activity of a new benzimidazole based Schiff base 2-(1-methyl-1-H-benzimidazol-2-yl)phenyl)imino)methyl)phenol (HL) and dicopper(II) complex [{Cu(L)NO3}2] (CuL) containing L− has been described. Both HL and CuL have been meticulously characterized by satisfactory elemental analyses, FT-IR, NMR, ESI-MS, electronic absorption and emission spectroscopy, and their structures unambiguously determined by X-ray single crystal analyses. Titration studies (absorption and emission) revealed interaction of the ligand and its dicopper(II) complex with DNA/BSA and stronger affinity of the CuL relative to HL. Binding of the HL and CuL with DNA/BSA have been validated by in silico studies and their cytotoxic effect on human breast cancer cell lines (MCF-7) by MTT assay. IC50 values (458 μM and 22 μM for HL, CuL) clearly suggested substantial cytotoxicity of the complex CuL toward MCF-7 compared to the ligand HL. Greater antiproliferative efficacy of the CuL in contrast to HL has been evidenced by fluorescence activated cell sorting (FACS) and AO/EB fluorescence staining. The possible mode of the apoptotic pathway for CuL has further been affirmed by reactive oxygen species (ROS) generation studies.

RGD-TPGS decorated theranostic liposomes for brain targeted delivery

The aim of this work was to formulate RGD-TPGS decorated theranostic liposomes, which contain both docetaxel (DTX) and quantum dots (QDs) for brain cancer imaging and therapy. RGD conjugated TPGS (RGD-TPGS) was synthesized and conjugation was confirmed by Fourier transform infrared (FTIR) spectroscopy and electrospray ionisation (ESI) mass spectroscopy (ESI-MS). The theranostic liposomes were prepared by the solvent injection method and characterized for their particle size, polydispersity, zeta-potential, surface morphology, drug encapsulation efficiency, and in-vitro release study. Biocompatibility and safety of theranostic liposomes were studied by reactive oxygen species (ROS) generation study and histopathology of brain. In-vivo study was performed for determination of brain theranostic effects in comparison with marketed formulation (Docel™) and free QDs. The particle sizes of the non-targeted and targeted theranostic liposomes were found in between 100 and 200nm. About 70% of drug encapsulation efficiency was achieved with liposomes. The drug release from RGD-TPGS decorated liposomes was sustained for more than 72h with 80% of drug release. The in-vivo results demonstrated that RGD-TPGS decorated theranostic liposomes were 6.47- and 6.98-fold more effective than Docel™ after 2h and 4h treatments, respectively. Further, RGD-TPGS decorated theranostic liposomes has reduced ROS generation effectively, and did not show any signs of brain damage or edema in brain histopathology. The results of this study have indicated that RGD-TPGS decorated theranostic liposomes are promising carrier for brain theranostics.

Transferrin receptor targeted PLA-TPGS micelles improved efficacy and safety in docetaxel delivery

The aim of this work was to develop targeted polymeric micelles of poly-lactic acid-D-α-tocopheryl polyethylene glycol 1000 succinate (PLA-TPGS), which are assembled along with D-alpha-tocopheryl polyethylene glycol 1000 succinate-transferrin conjugate (TPGS-Tf), and loaded docetaxel (DTX) as a model drug for enhanced treatment of lung cancer in comparison to non-targeted polymeric micelles and DTX injection (Docel™). A549 human lung cancer cells were employed as an in vitro model to access cytotoxicity study of the DTX loaded polymeric micelles. The safety of DTX formulations were studied by the measurement of alkaline phosphatase (ALP), lactate dehydrogenase (LDH) and total protein levels in bronchoalveolar lavage (BAL) fluid of rats after the treatments. The IC50 values demonstrated that the non-targeted and transferrin receptor targeted polymeric micelles could be 7 and 70 folds more effective than Docel™ after 24 h treatment with the A549 cells. Results suggested that transferrin receptor targeted polymeric micelles have showed better efficacy and safety than the non-targeted polymeric micelles and Docel™.

Transferrin liposomes of docetaxel for brain-targeted cancer applications: formulation and brain theranostics.

Abstract Diagnosis and therapy of brain cancer was often limited due to low permeability of delivery materials across the blood–brain barrier (BBB) and their poor penetration into the brain tissue. This study explored the possibility of utilizing theranostic d-alpha-tocopheryl polyethylene glycol 1000 succinate mono-ester (TPGS) liposomes as nanocarriers for minimally invasive brain-targeted imaging and therapy (brain theranostics). The aim of this work was to formulate transferrin conjugated TPGS coated theranostic liposomes, which contain both docetaxel and quantum dots (QDs) for imaging and therapy of brain cancer. The theranostic liposomes with and without transferrin decoration were prepared and characterized for their particle size, polydispersity, morphology, drug encapsulation efficiency, in-vitro release study and brain theranostics. The particle sizes of the non-targeted and targeted theranostic liposomes were found below 200 nm. Nearly, 71% of drug encapsulation efficiency was achieved with liposomes. The drug release from transferrin conjugated theranostic liposomes was sustained for more than 72 h with 70% of drug release. The in-vivo results indicated that transferrin receptor-targeted theranostic liposomes could be a promising carrier for brain theranostics due to nano-sized delivery and its permeability which provided an improved and prolonged brain targeting of docetaxel and QDs in comparison to the non-targeted preparations.

Vitamin E TPGS conjugated carbon nanotubes improved efficacy of docetaxel with safety for lung cancer treatment

The aim of this work was to develop multi-walled carbon nanotubes (MWCNT), which were coated or covalently conjugated with d-alpha-tocopheryl polyethylene glycol 1000 succinate (TPGS), and loaded docetaxel as a model drug for effective treatment to lung cancer in comparison with the commercial docetaxel injection (Docel™). The human lung cancer cells (A549 cells) were employed as an in-vitro model to access cellular uptake, cytotoxicity, cellular apoptosis, cell cycle analysis, and reactive oxygen species (ROS) study of the docetaxel/coumarin-6 loaded MWCNT. The safety of MWCNT formulations were studied by the measurements of alkaline phosphatase (ALP), lactate dehydrogenase (LDH) and total protein levels in bronchoalveolar lavage (BAL) fluid of rats after the treatments. The IC50 values demonstrated that the TPGS conjugated MWCNT could be 80 folds more effective than Docel™ after 24h treatment with the A549 cells. Flow cytometry analysis confirmed that cancerous cells were appeared significantly (P<0.05) in the sub G1 phase for TPGS conjugated MWCNT. Results of TPGS conjugated MWCNT have showed better efficacy with safety than non-coated or TPGS coated MWCNT and Docel™.