An Anti-inflammatory Fe O -Porphyrin Nanohybrid Capable of Apoptosis through Upregulation of p21 Kinase Inhibitor Having Immunoprotective Properties under Anticancer PDT Conditions.

We report the influence of Fe O nanoparticles (NPs) on porphyrins in the development of photosensitizers (PSs) for efficient photodynamic therapy (PDT) and possible post-PDT responses for inflicting cancer cell death. Except for Au, most metal-based nanomaterials are unsuitable for clinical applications. The US Food and Drug Administration and other agencies have approved Feraheme and a few other iron oxide NPs for clinical use, paving the way for novel biocompatible immunoprotective superparamagnetic iron oxide nanohybrids to be developed as nanotherapeutics.

Photodynamic activity attained through the ruptured π-conjugation of pyridyl groups with a porphyrin macrocycle: synthesis and the photophysical and photobiological evaluation of 5-mono-(4-nitrophenyl)-10,15,20-tris-[4-(phenoxymethyl)pyridine]-porphyrin and its Zn(ii) complex.

This article compares a reported hydrophobic and photobiologically inert porphyrin synthon, (NPh)TPyP, bearing a single meso-4-nitrophenyl group and three meso-pyridyl groups (AB type) with a new photobiologically active metal-free porphyrin, PN, and its zinc-complex, PNZn, which bear a meso-4-nitrophenyl group along with three distal pyridyl groups. Both PN and PNZn experience ruptured π-conjugation with the porphyrin macrocycle and attain hydrophilicity, as indicated via density functional theory (DFT) calculations, becoming photobiologically active under in vitro conditions. The non-invasive photodynamic activity (PDA) predominantly shown by the zinc-complex PNZn (with higher hydrophilicity) towards KRAS-mutated human lung-cancer cells (A549) was studied.

Metal nanoparticle alters adenine induced charge transfer kinetics of vitamin K3 in magnetic field.

In this article, we highlight the alterations in the photoinduced electron transfer (ET) and hydrogen atom transfer (HAT) pathways between an anti-tumor drug vitamin-K3 (MQ) and a nucleobase adenine (ADN) in the presence of gold (Au) and iron (Fe) nanoparticles (NPs). Inside the confined micellar media, with laser flash photolysis corroborated with an external magnetic field (MF), we have detected the transient geminate radicals of MQ and ADN, photo-generated through ET and HAT. We observe that the presence of AuNP on the MQ-ADN complex (MQ-ADN) assists HAT by limiting the ET channel, on the other hand, FeNP on the MQ-ADN complex (MQ-ADN) mostly favors a facile PET.

-Thiophenium Porphyrins and Their Zn(II) Complexes: A New Category of Cationic Photosensitizers.

A new category of cationic -thiophenium porphyrins are introduced as possible alternatives to the popular -pyridinium porphyrins. Combinations of cationic porphyrins bearing -2-methylthiophenium and -4-hydroxyphenyl moieties (AB type) and (AB type) along with their zinc(II) complexes and , are reported. The increase in the number of thienyl groups attached to the -positions of the porphyrin derivatives (AB frame) has been shown to impart longer fluorescence lifetimes and stronger photocytotoxicity toward A549 lung cancer cells, as evident with and its corresponding diamagnetic metal complex The photoactivated imparts an early stage reactive oxygen species (ROS) upregulation and antioxidant depletion in A549 cells and contributes to the strongest oxidative stress-induced cell death mechanism in the series.

Probing the Hydrogen Bond Involving Acridone Trapped in a Hydrophobic Biological Nanocavity: Integrated Spectroscopic and Docking Analyses.

Spectroscopic analyses reveal that acridone (AD) penetrates through the structure and enters the hydrophobic cavity of the protein β-lactoglobulin (βLG). Although the protein contains two tryptophan (Trp) residues, AD interacts with only one (Trp-19), which is authenticated by the appearance of a single isoemissive point in TRANES. Alteration in the secondary structure of the protein while AD pierces through βLG is evident from the circular dichroism spectroscopic study.

Preferential photochemical interaction of Ru (III) doped carbon nano dots with bovine serum albumin over human serum albumin.

The excitation wavelength dependent emission of carbon nano dots (CNDs) restricts their use in photophysical studies. However, instead of bare CNDs, the amine coated Ru (III) doped CNDs (Ru:CNDEDAs) are quite eligible to generate excitation wavelength independent fluorescence with high quantum yield. Herein, we report a detailed study on the photochemical interaction between two different serum albumins, bovine serum albumin (BSA) and human serum albumin (HSA), with Ru:CNDEDAs synthesized in our laboratory, using steady-state and time-resolved spectroscopic techniques.

Calmodulin regulates MGRN1-GP78 interaction mediated ubiquitin proteasomal degradation system.

The mechanism by which the endoplasmic reticulum (ER) ubiquitin ligases sense stress to potentiate their activity is poorly understood. GP78, an ER E3 ligase, is best known for its role in ER-associated protein degradation, although its activity is also linked to mitophagy, ER-mitochondria junctions, and MAPK signaling, thus highlighting the importance of understanding its regulation. In healthy cells, Mahogunin really interesting new gene (RING) finger 1 (MGRN1) interacts with GP78 and proteasomally degrades it to alleviate mitophagy.

DNA Damage and Apoptosis Induction in Cancer Cells by Chemically Engineered Thiolated Riboflavin Gold Nanoassembly.

Herein we have engineered a smart nuclear targeting thiol-modified riboflavin-gold nano assembly, RfS@AuNPs, which accumulates selectively in the nucleus without any nuclear-targeting peptides (NLS/RGD) and shows photophysically in vitro DNA intercalation. A theoretical model using Molecular Dynamics has been developed to probe the mechanism of formation and stability as well as dynamics of the RfS@AuNPs in aqueous solution and within the DNA microenvironment. The RfS@AuNPs facilitate the binucleated cell formation that is reflected in the significant increase of DNA damage marker, γ-H2AX as well as the arrest of most of the HeLa cells at the pre-G1 phase indicating cell death.

Benzamide porphyrins with directly conjugated and distal pyridyl or pyridinium groups substituted to the porphyrin macrocycles: Study of the photosensitising abilities as inducers of apoptosis in cancer cells under photodynamic conditions.

Amphiphilic porphyrin photosensitisers (PSs) having combinations of directly substituted pyridyl group(s) at the meso-position of a porphyrin macrocycle, and/or indirectly linked pyridyl groups as benzamide derivatives are reported. The compounds 5,10,15,20-tetrakis-(4-pyridylbenzamide)porphyrin (A.2), 5,10,15,20-tetra[N-(pyridine-4-yl)benzamidium] porphyrin (A.

Constrained Photophysics of 5,7-dimethoxy-2,3,4,9-tetrahydro-1H-carbazol-1-one in the Bioenvironment of Serum Albumins: A Spectroscopic Endeavour Supported by Molecular Docking Analysis.

This paper vividly indicates that steady state as well as time-resolved fluorescence techniques can serve as highly sensitive monitors to explore the interactions of 5,7-dimethoxy-2,3,4,9-tetrahydro-1H-carbazol-1-one with model transport proteins, bovine serum albumin (BSA) and human serum albumin (HSA). Besides these, we have used fluorescence anisotropy study to assess the degree of restrictions imparted by the micro-environments of serum albumins. Again, to speculate the triplet excited state interaction between such fluorophore and albumin proteins (BSA& HSA), laser flash-photolysis experiments have been carried out.

Micellar control over tautomerization and photo-induced electron transfer of Lumichrome in the presence of aliphatic and aromatic amines: a transient absorption study.

Lumichrome (Lc), a molecule consisting of a trinuclear alloxazine moiety is our present subject of interest. This molecule is subjected to tautomerization in the presence of pyridine, acetic acid, etc, through the formation of an eight-membered ring. In our present contribution, we have attempted to analyze the influence of the presence of an aliphatic amine, triethylamine (TEA) and an aromatic amine, N,N-dimethylaniline (DMA) in the double proton transfer step of the tautomerization as well as the photo-induced electron transfer (PET) from those amines to Lc.

Structure dependent selective efficacy of pyridine and pyrrole based Cu(II) Schiff base complexes towards in vitro cytotoxicity, apoptosis and DNA-bases binding in ground and excited state.

This work highlights a systematic and comparative study of the structure-dependent influence of a series of biologically active Cu(II) Schiff base complexes (CSCs) on their in vitro cytotoxicity, apoptosis and binding with polymeric DNA-bases in ground and photo-excited states. The structure-activity relationship of the closely resembled CSCs towards in vitro cytotoxicity and apoptosis against cervical cancerous HeLa and normal human diploid WI-38 cell lines has been investigated by MTT assay and FACS techniques respectively. The steady-state and time-resolved spectroscopic studies have also been carried out to explore the selective binding affinities of the potential complexes towards different polymeric nucleic acid bases (poly d(A), poly d(T), poly d(G), poly d(C), Poly d(G)-Poly d(C)), which enlighten the knowledge regarding their ability in controlling the structure and medium dependent interactions in 'ground' and 'excited' states.

Development of a Triplet-Triplet Absorption Ruler: DNA- and Chromatin-Mediated Drug Molecule Release from a Nanosurface.

Triplet-triplet (T-T) absorption spectroscopy has been used successfully as a molecular ruler to understand the actual release process of sanguinarine as a drug molecule from a gold nanoparticle surface in the presence of cell components, that is, DNA and chromatin. The obtained results have been verified by fluorescence and surface-enhanced Raman spectroscopy (SERS), and a plausible explanation has been put forward to describe the underestimation and overestimation of the percentage (%) of the release of drug molecules measured by fluorescence- and SERS-based techniques, respectively, over the highlighted T-T absorption spectroscopy. Because of the intrinsic nature of absorption, the reported T-T absorption spectroscopic assay overpowers fluorescence- and SERS-based assays, which are limited by the long-range interaction and nonlinear dependence of the concentration of analytes, respectively.

Monitoring the Competence of a New Keto-tetrahydrocarbazole Based Fluorosensor Under Homogeneous, Micro-Heterogeneous and Serum Albumin Environments.

We present here a detailed photophysical study of a recently synthesised fluorophore 8-methyl-8,9-dihydro-5H-[1,3]dioxolo[4,5-b]carbazol-6(7H)-one. This is a synthetic precursor of bio-active carbazole skeleton Clausenalene. Spectroscopic investigation of the fluorophore has been carried out in different protic and aprotic solvents, as well as in binary solvent mixtures, using absorption, steady-state and time-resolved fluorescence techniques.

Antibacterial efficacy of acridine derivatives conjugated with gold nanoparticles.

Adsorption of acridine derivatives viz. 9-aminoacridine hydrochloride hydrate (9AA-HCl), acridine yellow (AY), acridine orange (AO), and proflavine (Pro) on citrate stabilized gold nanoparticle surface were studied using different analytical techniques like UV-vis absorption spectroscopy, Fourier transform infrared spectroscopy (FT-IR), and transmission electron microscopy (TEM). The amine moiety of acridine derivative binds strongly to the gold nanoparticles as confirmed by spectroscopic studies.

Ni(II)-Schiff base complex as an enzyme inhibitor of hen egg white lysozyme: a crystallographic and spectroscopic study.

The engineering of protein-small molecule interactions becomes imperative today to recognize the essential biochemical processes in living systems. Here we have investigated the interaction between hen egg white lysozyme (HEWL) and a newly synthesized small, simple nickel Schiff base complex (NSC) {(N(1)E,N(2)E)-N(1),N(2)-bis(pyridine-2-ylmethylene)propane-1,2-diaminenickel(II)} using different spectroscopic techniques. We attempted to determine the exact site of the interaction by crystallography.

Potency of photoinduced electron transfer and antioxidant efficacy of pyrrole and pyridine based Cu(II)-Schiff complexes while binding with CT-DNA.

Here we report a systematic and comparative study to define a correlation between the structure and function of a series of simple, biologically active small inorganic Schiff base copper complexes for the occurrence of charge transfer phenomenon in calf thymus DNA (CT-DNA) using transient absorption spectroscopy corroborated with magnetic field effect. Four copper(II) Schiff base complexes with differently substituted heterocyclic ligands with antioxidant activity have been used. The binding constants of the order of ∼ 10(4) support the moderate binding affinity of the complexes towards CT-DNA.

Tuning the solution phase photophysics of two de novo designed hydrogen bond sensitive 9-methyl-2,3,4,9-tetrahydro-1H-carbazol-1-one derivatives.

Two new fluorophores, 6,7-dimethoxy-9-methyl-2,3,4,9-tetrahydro-1H-carbazol-1-one (DMTCO) and 5-methyl-8,9-dihydro-5H-[1,3]dioxolo[4,5-b]carbazol-6(7H)-one (MDDCO), first of their kind, have been synthesized from the corresponding methoxy and methylenedioxy derivatives of 2,3,4,9-tetrahydro-1H-carbazol-1-one respectively. Comprehensive photophysical characterization of these compounds has been carried out in sixteen different homogeneous solvents and binary solvent mixtures. Both of these compounds are sensitive to solvent polarity, but the sensitivity is much higher in electronic excited state observed by steady-state and time-resolved fluorescence experiments than in ground state studied by UV-vis absorption spectroscopy.

Protein interactions of Merocyanine 540: spectroscopic and crystallographic studies with lysozyme as a model protein.

Spectroscopic and crystallographic studies reveal that Merocyanine 540 (MC 540), a well-known therapeutically important anionic cyanine dye, interacts with hen egg white lysozyme in ground state. The formation of the complex is validated by two isosbestic points in absorption spectra of lysozyme with varied concentration of MC 540 and appearance of an isodichroic point in induced CD spectra of MC 540 with lysozyme. The blue shift of fluorescence maximum of lysozyme in presence of MC 540 shows hydrophobic effect on Trp due to complex formation probably through cooperative binding.

Excimer of 9-aminoacridine hydrochloride hydrate in confined medium: an integrated experimental and theoretical study.

We aim to find out the extent of stability of the excimer of 9-aminoacridine hydrochloride hydrate (9AA), a prospective PDT drug, in different confined media with varying cavity size. When confined in cetyltrimethyl ammonium bromide micelles, although at low concentration of 9AA, only a single distinct peak (λ(max) at 460 nm) with a shoulder at 485 nm is observed in steady-state fluorescence spectrum, yet with increase in concentration the peak and the shoulder merge with simultaneous emergence of another peak at 535 nm, which is assigned to excimer. Similar behavior is also observed in Triton-X, crown ether, α-cyclodextrin, β-cyclodextrin, and homogeneous aqueous medium.

Prototropic interactions of pyrimidine nucleic acid bases with acridine: a spectroscopic investigation.

In this article, we have investigated the interactions of three pyrimidine nucleic acid bases, cytosine (C), thymine (T), and uracil (U) with acridine (Acr), an N-heterocyclic DNA intercalator, through the changes in photophysics of Acr inside SDS micelles. Fluorescence of AcrH(+)* at 478 nm and its lifetime are quenched on addition of C, T, and U, while a concomitant increment of Acr* is observed only with C. However, the relative amplitude of Acr* increases with a simultaneous decrease in AcrH(+)* only with C.

Oxidative interaction between OxyHb and ATP: a spectroscopic study.

The binding mode between oxyhemoglobin (oxyHb) and adenosine triphosphate (ATP) has been studied using absorption and fluorescence spectroscopy. OxyHb forms a ground state complex with ATP supported by five isosbestic points which appear in absorption spectra of oxyHb in buffer solution on addition of ATP. Moreover, the changes in absorption spectra suggest an oxidative interaction between the particular interacting systems.

Nickel(II)-Schiff base complex recognizing domain II of bovine and human serum albumin: spectroscopic and docking studies.

It has been spectroscopically monitored that a mononuclear nickel(II)-Schiff base complex {[NiL]·CH(3)OH=NSC} exhibits greater binding affinity for bovine serum albumin (BSA) than that of its human counterpart (HSA). Moreover the modes of binding of NSC with the two serum albumins also differ significantly. Docking studies predict a relatively rare type of 'superficial binding' of NSC at domain IIB of HSA with certain mobility whereas for BSA such phenomena has not been detected.

Interaction of Merocyanine 540 with serum albumins: photophysical and binding studies.

Photophysical studies on binding interactions of a negatively charged anti-tumor photosensitizer, Merocyanine 540 (MC 540), with serum proteins, bovine serum albumin (BSA) and human serum albumin (HSA), have been performed using absorption and steady-state as well as time-resolved fluorescence techniques. Formation of ground state complex has been confirmed from the detailed studies of absorption spectra of MC 540 in presence of SAs producing isosbestic points. Binding between the proteins and MC 540, which perturbs the existing equilibrium between the fluorescent monomer and its non-fluorescent dimer, induces a remarkable enhancement in fluorescence anisotropy and intensity of MC 540 along with a red shift of its maximum.