Novel 2D MXene Cobalt Ferrite (CoF@Ti3C2) Composite: A Promising Photothermal Anticancer In Vitro Study.

In search of materials with superior capability of light-to-heat (photothermal) conversion, biocompatibility, and confinement of active photothermal materials within the cells, novel magnetic MXene-based nanocomposites are found to possess all of these criteria. The CoF@Ti3C2 composite is fabricated by a simple two-step method, including an exfoliation strategy followed by sonochemical method. MXene composite has been modified with polyvinylpyrrolidone (PVP) to improve the stability in physiological conditions. The synthesized composite was characterized with multiple analytical tools. In vitro photothermal conversion efficiency of composite was determined by the time constant method and achieved η = 34.2% with an NIR 808 nm laser. In vitro, cytotoxicity studies conducted on human malignant melanoma (Ht144) and cells validated the photothermal property of the CoF@Ti3C2-PVP composite in the presence of an NIR laser (808 nm, 1.0 W cm-2), with significantly increased cytotoxicity. Calculated IC50 values were 86 µg/mL with laser, compared to 226 µg/mL without the presence of NIR laser. Microscopic results demonstrated increased apoptosis in the presence of NIR laser. Additionally, hemolysis assay confirmed biocompatibility of CoF@Ti3C2-PVP composite for intravenous applications at the IC50 concentration. The research described in this work expands the potential applications of MXene-based nanoplatforms in the biomedical field, particularly in photothermal therapy (PTT). Furthermore, the addition of cobalt ferrite serves as a magnetic nanocomposite, which eventually helps to confine therapeutic photothermal materials inside the cells, provides enhanced photothermal conversion efficiency, and creates externally controlled theranostic nanoplatforms for cancer therapy.

Magnetoelectric core-shell CoFe2O4@BaTiO3 nanorods: their role in drug delivery and effect on multidrug resistance pump activity in vitro.

Nanoparticle mediated targeted drug delivery has become a widespread area of cancer research to address premature drug delivery problems. We report the synthesis of magneto-electric (ME) core-shell cobalt ferrite-barium titanate nanorods (CFO@BTO NRs) to achieve "on demand" drug release in vitro. Physical characterizations confirmed the formation of pure CFO@BTO NRs with appropriate magnetic and ferroelectric response, favorable for an externally controlled drug delivery system. Functionalization of NRs with doxorubicin (DOX) and methotrexate (MTX) achieved up to 98% drug release in 20 minutes, under a 4 mT magnetic field (MF). We observed strong MF and dose dependent cytotoxic response in HepG2 and HT144 cells and 3D spheroid models (p < 0.05). Cytotoxicity was characterized by enhanced oxidative stress, causing p53 mediated cell cycle arrest, DNA damage and cellular apoptosis via downregulation of Bcl-2 expression. In addition, MF and dose dependent inhibition of Multidrug Resistance (MDR) pump activity was also observed (p < 0.05) indicating effectivity in chemo-resistant cancers. Hence, CFO@BTO NRs represent an efficient carrier system for controlled drug delivery in cancer nanotherapeutics, where higher drug uptake is a prerequisite for effective treatment.

Nanogold morphologies with the same surface chemistry provoke a different innate immune response: An in-vitro and in-vivo study.

Gold nanomaterials (GNMs) have unique optical properties with less antigenicity, and their physicochemical properties have strong relation with an immunological response at bio-interface including antigenicity. An interpretation of this correlation would significantly impact on the clinical and theranostic applications of GNMs. Herein, we studied the effect of GNMs morphology on the cytotoxicity (in-vitro), innate immune responses, hepatotoxicity, and nephrotoxicity (in-vivo studies) using gold nano-cups (GNCs), porous gold nanospheres (PGNSs) and solid gold nano particles (SGNPs) coated with the same ligand to ensure similar surface chemistry. The cytotoxicity was assessed via sulfo-rhodamine B (SRB) assay, and the cytotoxicity data showed that morphological features at nanoscale dimensions like surface roughness and hollowness etc. have a significant impact on cellular viability. The biochemical and histopathological study of liver and kidney tissues also showed that all GNMs did not show any toxicity even at high concentration (100 µL). The relative quantification of cytokine gene expression of TNF-α, IFN-γ, IL-4, 1L-6, and 1L-17 (against each morphology) was checked after in-vivo activation in mice. Among the different nanogold morphologies, PVP stabilized GNCs (PVP-GNCs) showed the highest release of pro-inflammatory cytokines, which might be due to their high surface energy and large surface area for exposure as compared to other nanogold morphologies studied. The pro-inflammatory cytokine release could be suppressed by coating with some anti-inflammatory polymer, i.e., inulin. The in-vitro results of pro-inflammatory (TNF-α, IL-1) cytokines also suggested that all GNMs may induce activation of macrophages and Th1 immune response. The in-vivo activation results showed a decrease in mRNA expression of the cytokines (TNF-α, IFN-γ, IL-4, 1L-6 and 1L-17). Based on these findings, we proposed that the shape and morphology of GNMs control their immune response at nano-bio interface, and it must be considered while designing their role for different biomedical applications like immuno-stimulation and bio-imaging.

In Silico and In Vitro Analysis of Helicobacter pullorum Type Six Secretory Protein Hcp and Its Role in Bacterial Invasion and Pathogenesis.

Helicobacter pullorum is a human zoonotic pathogen transmitted through poultry where it is associated with vibrionic hepatitis and colitis. Hemolysin co-regulated protein (Hcp) is an important structural as well as effector protein of type six secretory system; however, its role in H. pullorum invasion and pathogenesis has not been elucidated. In this study, we predicted the Helicobacter pullorum Hcp (HpuHcp) structure and identified Campylobacter jejuni Hcp (CjHcp) as its nearest homologue. Analysis of the predicted structure shows several common bacterial Hcp motifs like Protein kinase C phosphorylation site, Casein kinase II phosphorylation site, N-myristoylation site, cAMP-and cCGMP-dependent protein kinase phosphorylation site, N-glycosylation site. The presence of unique microbodies C-terminal targeting signal domain was present in HpuHcp which was seen for the first time in CjHcp. This could indicate that Hcp is a structural protein as well as a secretory protein. Moreover, the presence of a deamidase domain, similar to the tecA of Burkholderia cenocepacia an opportunistic pathogen, may help in bacterial internalization as it depolymerises the membranous actin by deamidation of the host cell Rho GTPases cdc42 and Rac1, which was supported by increased invasion of hepatocytes by Hcp-positive isolates.

Biocompatibility and cytotoxicity in vitro of surface-functionalized drug-loaded spinel ferrite nanoparticles.

In this study, poly(isobutylene-alt-maleic anhydride) (PMA)-coated spinel ferrite (MFe2O4, where M = Fe, Co, Ni, or Zn) nanoparticles (NPs) were developed as carriers of the anticancer drugs doxorubicin (DOX) and methotrexate (MTX). Physical characterizations confirmed the formation of pure cubic structures (14-22 nm) with magnetic properties. Drug-loaded NPs exhibited tumor specificity with significantly higher (p < 0.005) drug release in an acidic environment (pH 5.5). The nanoparticles were highly colloidal (zeta potential = -35 to -26 mV) in deionized water, phosphate buffer saline (PBS), and sodium borate buffer (SBB). They showed elevated and dose-dependent cytotoxicity in vitro compared to free drug controls. The IC50 values ranged from 0.81 to 3.97 µg/mL for HepG2 and HT144 cells, whereas IC50 values for normal lymphocytes were 10 to 35 times higher (18.35-43.04 µg/mL). Cobalt ferrite (CFO) and zinc ferrite (ZFO) NPs were highly genotoxic (p < 0.05) in cancer cell lines. The nanoparticles caused cytotoxicity via oxidative stress, causing DNA damage and activation of p53-mediated cell cycle arrest (significantly elevated expression, p < 0.005, majorly G1 and G2/M arrest) and apoptosis. Cytotoxicity testing in 3D spheroids showed significant (p < 0.05) reduction in spheroid diameter and up to 74 ± 8.9% of cell death after two weeks. In addition, they also inhibited multidrug resistance (MDR) pump activity in both cell lines suggesting effectivity in MDR cancers. Among the tested MFe2O4 NPs, CFO nanocarriers were the most favorable for targeted cancer therapy due to excellent magnetic, colloidal, cytotoxic, and biocompatible aspects. However, detailed mechanistic, in vivo cytotoxicity, and magnetic-field-assisted studies are required to fully exploit these nanocarriers in therapeutic applications.

Litchi chinensis inspired nanoformulations: a synergy guided approach for unraveling promising cytotoxic attributes of metal and nonmetal conjugates.

In present study, diverse Litchi chinensis-mediated nanostructures in combination with 5-fluorouracil drug were fabricated viz. Au, Se, Ag, Ag-Se, Ag-Au, 5-FU Ag-Se and 5-FU Ag-Au with subsequent characterization and scrutinization of their anticarcinogenic capabilities. UV-Visible spectroscopic analysis confirmed the state transition for each precursor salt. XRD and transmission electron microscopy analysis revealed spherical/quasispherical nanostructures with monoclinic crystalline organization ranged between 18 nm and 38 nm. FTIR analysis revealed fabricated nanoparticles to be capped with various phytoconstituents. DLS and Zeta potential analysis of unloaded and drug-loaded bielemental nanoparticles (BNPs) showed comparatively large hydrodynamic particle size distribution and sufficient stability of nanoparticles. BNPs showed promising lethality concentrations for brine shrimp (LC50 < 2 µg/ml) and antitumor (LC50 < 10 µg/ml) assessments. These findings were in positive correlation with the antioxidant inhibitory concentrations IC50 (74.2-180.1 µg/ml) of the tested entities. Ag-Se and Ag-Au were loaded with 5-FU (loading efficiency of 47% ± 1.14 and 25% ± 0.32, respectively) in light of their promising cytotoxic actions. All nanostructures showed profound hemocompatibility with maximum hemolytic activity as low as 2.4%. Highly significant difference (P < 0.01) was observed in antineoplastic potentials of unloaded and 5-FU loaded BNPs against HepG2 and HT144, with most substantial IC50 for 5-FU Ag-Au (8.95 ± 2.86 µg/ml). 5-FU Ag-Au was identified as a significant inducer of DNA fragmentation with maximum relative tail moment (HepG2: 3.45 ± 0.21) among all treatments.

Genome sequence analysis and bioactivity profiling of marine-derived actinobacteria, Brevibacterium luteolum, and Cellulosimicrobium funkei.

Genome analysis gives important insights into the biosynthetic potential of marine actinobacteria. The genomes of two marine actinomycetes Brevibacterium luteolum MOSEL-ME10a and Cellulosimicrobium funkei MOSEL-ME6 were sequenced to identify the biosynthetic gene clusters (BGCs). Additionally, anti-proliferative, antioxidant, and enzyme inhibitory activities were studied in vitro. We report a total genome size of 2.77 Mb with GC content of 67.8% and 6.81 Mb with GC content of 69% for Brevibacterium sp. MOSEL-ME10a and Cellulosimicrobium sp. MOSEL-ME6, respectively. Biosynthetic gene clusters (BGCs) encoding different classes of natural products were predicted including terpenes, peptides, siderophores, ectoines, and bacteriocins. The bioactivity potential of crude extracts derived from these strains was evaluated. Notable anti-proliferative activity was observed against HepG2 cell line (hepatocellular carcinoma) with an IC50 value of 182 µg/mL for Brevibacterium sp. MOSEL-ME10a. Furthermore, antioxidant activity was assessed with IC50 values of 48.91 µg/mL and 102.5 µg/mL for Brevibacterium sp. MOSEL-ME10a and Cellulosimicrobium sp. MOSEL-ME6, respectively. Protein kinase inhibition potential was observed only for Brevibacterium sp. MOSEL-ME10a. Our study also reports lower amylase enzyme inhibition potential for both strains. Moreover, both crude extracts showed only slight-to-no toxic effect on erythrocytes at 400 µg/mL and below, indicating erythrocyte membrane stability. Our data present the genomic features revealing biosynthetic potential of marine actinobacteria as well as biological activities found in vitro.

Putative second hit rare genetic variants in families with seemingly GBA-associated Parkinson's disease.

Rare variants in the beta-glucocerebrosidase gene (GBA1) are common genetic risk factors for alpha synucleinopathy, which often manifests clinically as GBA-associated Parkinson's disease (GBA-PD). Clinically, GBA-PD closely mimics idiopathic PD, but it may present at a younger age and often aggregates in families. Most carriers of GBA variants are, however, asymptomatic. Moreover, symptomatic PD patients without GBA variant have been reported in families with seemingly GBA-PD. These observations obscure the link between GBA variants and PD pathogenesis and point towards a role for unidentified additional genetic and/or environmental risk factors or second hits in GBA-PD. In this study, we explored whether rare genetic variants may be additional risk factors for PD in two families segregating the PD-associated GBA1 variants c.115+1G>A (ClinVar ID: 93445) and p.L444P (ClinVar ID: 4288). Our analysis identified rare genetic variants of the HSP70 co-chaperone DnaJ homolog subfamily B member 6 (DNAJB6) and lysosomal protein prosaposin (PSAP) as additional factors possibly influencing PD risk in the two families. In comparison to the wild-type proteins, variant DNAJB6 and PSAP proteins show altered functions in the context of cellular alpha-synuclein homeostasis when expressed in reporter cells. Furthermore, the segregation pattern of the rare variants in the genes encoding DNAJB6 and PSAP indicated a possible association with PD in the respective families. The occurrence of second hits or additional PD cosegregating rare variants has important implications for genetic counseling in PD families with GBA1 variant carriers and for the selection of PD patients for GBA targeted treatments.

Field-controlled magnetoelectric core-shell CoFe2O4@BaTiO3 nanoparticles as effective drug carriers and drug release in vitro.

The targeted drug release at tumor cells while sparing normal cells is a huge challenge. Core-shell magnetoelectric (ME) nanoparticles have addressed this problem using shape-dependent magneto-electric attributes. The colloidally stable, core-shell cobalt ferrite@barium titanate (CFO@BTO) ME nanoparticles (NPs) used for in vitro study were synthesized using sonochemical method. The structural characteristics and core-shell morphology were analyzed by X-ray Diffraction (XRD) and Transmission Electron Microscopy (TEM) respectively. Further magnetic and exchange coupling between two phases of ME nanostructures were studied at room temperature. Colloidal stability was studied in different suspension solutions (Water, SBB, PBS, and DMEM) using dynamic light scattering. Subsequently, the synthesized nanoparticles were functionalized with anticancer drugs including doxorubicin and methotrexate up to 80% via (EDC) chemistry. In vitro cytotoxicity studies carried out on human hepatocellular carcinoma (HepG2) and human malignant melanoma (HT144), cells validated the magneto-electric property of CFO@BTO nano-carriers in the presence of external magnetic field (5 mT), with significantly enhanced cytotoxicity when compared to free drugs and without field replicates. The resulted IC50 values ranging from 5.3-7.3 µg/ml compared to 30.1-43.1 µg/ml in the absence of a magnetic field also confirmed the involved physical attributes of magnetoelectric nanostructures. The fluorescent microscopy results also indicated the increased apoptosis in magnetic field-assisted samples. Finally, hemolysis assay indicated the suitability of CFO@BTO nano-carriers for intravenous applications at IC50 concentration.

Alginate-caseinate based pH-responsive nano-coacervates to combat resistant bacterial biofilms in oral cavity.

Biofilm associated microbial resistance is a major concern in oral health and hygiene. Nano-antimicrobials (NAMs) having natural antibiotic replacers e.g. nisin are the possible solution to treat oral infections. In this study, we have developed pH responsive, mucoadhesive protein-polysaccharide [sodium caseinate (NaC)-sodium alginate (AL)] coacervate based nano-carrier systems (PPC-NCS) to prevent and eradicate oral biofilms associated pathogens e.g. Enterococcus faecium, Staphylococcus epidermidis and Enterococcus faecalis. PPC-NCS were formed at pH 5 with highest encapsulation efficiency of 75.1 ± 1.2%, then at pH 6 (31 ± 1.1%) and 7 (15 ± 2%). SEM of PPC-NCS displayed smooth and round morphology. Particle size of PPC-NCS was observed to be 244 nm by DLS, with negative zeta potential (-47 ± 4.31 mV). In FTIR analysis, merging of OH stretching peak of NaC (2889.53 cm-1) and CH stretching of AL (2920 cm-1) with appearance of a new peak at 2062 cm-1 was observed that confirmed covalent and hydrogen bonding between two compounds. Antimicrobial and antibiofilm assays demonstrated better control of nisin loaded PPC-NCS against selected pathogens, while preventing and eradicating bacterial biofilms successfully without any cytotoxic effect. These results recommend that coacervates based NAMs are suitable carriers for pH-triggered release of antimicrobials in the buccal cavity to control biofilm associated oral infections.

Segregation and potential functional impact of a rare stop-gain PABPC4L variant in familial atypical Parkinsonism.

Atypical parkinsonian disorders (APDs) comprise a group of neurodegenerative diseases with heterogeneous clinical and pathological features. Most APDs are sporadic, but rare familial forms have also been reported. Epidemiological and post-mortem studies associated APDs with oxidative stress and cellular protein aggregates. Identifying molecular mechanisms that translate stress into toxic protein aggregation and neurodegeneration in APDs is an active area of research. Recently, ribonucleic acid (RNA) stress granule (SG) pathways were discussed to be pathogenically relevant in several neurodegenerative disorders including APDs. Using whole genome sequencing, mRNA expression analysis, transfection assays and cell imaging, we investigated the genetic and molecular basis of a familial neurodegenerative atypical parkinsonian disorder. We investigated a family with six living members in two generations exhibiting clinical symptoms consistent with atypical parkinsonism. Two affected family members suffered from parkinsonism that was associated with ataxia. Magnetic resonance imaging (MRI) of these patients showed brainstem and cerebellar atrophy. Whole genome sequencing identified a heterozygous stop-gain variant (c.C811T; p.R271X) in the Poly(A) binding protein, cytoplasmic 4-like (PABPC4L) gene, which co-segregated with the disease in the family. In situ hybridization showed that the murine pabpc4l is expressed in several brain regions and in particular in the cerebellum and brainstem. To determine the functional impact of the stop-gain variant in the PABPC4L gene, we investigated the subcellular localization of PABPC4L in heterologous cells. Wild-type PABPC4L protein localized predominantly to the cell nucleus, in contrast to the truncated protein encoded by the stop-gain variant p.R271X, which was found homogeneously throughout the cell. Interestingly, the wild-type, but not the truncated protein localized to RasGAP SH3 domain Binding Protein (G3BP)-labeled cytoplasmic granules in response to oxidative stress induction. This suggests that the PABPC4L variant alters intracellular distribution and possibly the stress granule associated function of the protein, which may underlie APD in this family. In conclusion, we present genetic and molecular evidence supporting the role of a stop-gain PABPC4L variant in a rare familial APD. Our data shows that the variant results in cellular mislocalization and inability of the protein to associate with stress granules.

Targeting of JAK-STAT Signaling in Breast Cancer: Therapeutic Strategies to Overcome Drug Resistance.

Rapidly emerging ground-breaking discoveries have provided near to complete resolution of breast cancer signaling landscape and scientists have mapped the knowledge gaps associated with proteins encoded by the human genome. Based on the insights gleaned from decades of research, it seems clear that ligands transmit distinct information through specific receptors that is processed into characteristically unique biological outputs. Advances in imaging, structural biology, proteomics and genome editing have helped us to gain new insights into JAK-STAT signaling and how alterations in this pathway contributed to development of breast cancer and metastatic spread. Data obtained through high-throughput technologies has started to shed light on signal-transducer complexes formed during JAK-STAT signaling. Pharmacologists and molecular biologists are focusing on the strategies to therapeutically target this pathway to overcome drug resistance associated with breast cancer.

A Comparative Evaluation of the Antiproliferative Activity against HepG2 Liver Carcinoma Cells of Plant-Derived Silver Nanoparticles from Basil Extracts with Contrasting Anthocyanin Contents.

Nanotechnology is a well-established and revolutionized field with diverse therapeutic properties. Several methods have been employed using different reducing agents to synthesize silver nanoparticles (AgNPs). Chemical mediated synthetic methods are toxic and resulted in non-desired effects on biological systems. Herein, we, synthesized silver nanoparticles using callus extract of purple basil (BC-AgNPs) and anthocyanin extract deriving from the same plant (i.e. purple basil) (AE-AgNPs), and systematically investigated their antiproliferative potential against HepG2 Liver Carcinoma Cells. The phyto-fabricated AgNPs were characterized by different techniques like UV-visible spectroscopy (UV-Vis), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Scanning electron microscopy (SEM) and Energy dispersive X-rays (EDX). Morphologically, both types of NPs were found spherical. The average size of BC-AgNPs and AE-AgNPs as revealed through XRD and SEM analyses were calculated as 50.97 ± 0.10 nm and 42.73 ± 1.24 nm, respectively. FT-IR spectral analysis demonstrates the existence of possible phytochemicals required for the capping and reduction of Ag ions. Herein, following solid phase extraction (SPE) coupled to HPLC analysis, we report for the first-time the anthocyanin mediated synthesis of AgNPs and conforming the successful capping of anthocyanin. Small sized AE-AgNPs showed significant cytotoxic effect against human hepatocellular carcinoma (HepG2) cell line as compared to BC-AgNPs. Therefore, the results revealed that the prevalent group of flavonoids present in purple basil is the anthocyanins and AE-AgNPs could be employed as potential anticancer agents in future treatments strategies.

Chitosan-albumin based core shell-corona nano-antimicrobials to eradicate resistant gastric pathogen.

In this study, protein/polysaccharide core-shell-corona (PP-CSC) nano delivery systems (NDS) were prepared by using bovine serum albumin (BSA) and chitosan (CS). The potential of PP-CSC-NDS for increasing the stability and bio-accessibility of ε-poly-l-lysine (ε-PL) as effective therapy for gastric Helicobacter pylori was investigated. The presence of CS-shell increased the size (223 ±â€¯1.7 nm) of BSA-core as compared to BSA-shell on CS-core (191 ±â€¯2.6 nm). Conversely, encapsulation efficiency of ε-PL was reduced for C(B)NDS [CS-shell on BSA-core] to 73 ±â€¯1% than 82 ±â€¯2% for B(C)NDS [BSA-shell on CS-core] due to cationic nature of ε-PL. Scanning electron microscopy of PP-CSC-NDS displayed smooth and non-flocculated morphology. FTIR analyses verified that the electrostatic interactions, H-bonding, and hydrophobic effects were involved in PP-CSC formation. Zeta analyses revealed that the net charge depends on the corona layer and the encapsulated antimicrobials. Moreover, CS corona improved the antimicrobial potential, controlled release, mucoadhesion and stability of ε-PL loaded C(B)NDS in simulated gastric fluid due to inherent antimicrobial and mucoadhesive properties of CS polymer. In contrast, protein corona improved the penetration into bacterial biofilms for better eradiation of H. pylori. Thus, conjugated nano-systems with selected corona can improve the overall efficacy of antimicrobials to develop effective nano-therapeutics against gastric infections.

Prevalence and role of Type six secretion system in pathogenesis of emerging zoonotic pathogen Helicobacter pullorum from retail poultry.

Helicobacter pullorum is an emerging zoonotic pathogen that causes gastroenteritis in chickens and inflammatory bowel disease in humans ingesting contaminated meat. However, the mechanism by which the bacterium causes disease is unclear. Type six secretion system (T6SS) plays a major role in bacterial pathogenesis and adaptation. Haemolysin coregulated protein (Hcp) plays a central role in the structure of the T6SS pilus and acts as effector protein in certain bacteria. In this study, H. pullorum isolated from 156 caecal samples of broiler chickens was screened for the presence of T6SS Hcp gene via PCR amplification. 30.7% of caecal and 18.3% of liver samples tested positive for presence of H. pullorum. From these positive samples, 29.7% possessed the T6SS gene. In bacterial co-culture experiments, significant loss of viability (81.6-39.1%) was observed for H. pullorum-infected hepatocytes and presence of Hcp did not contribute to the loss of cell viability. Nevertheless, infection of erythrocytes with Hcp-positive isolates was associated with greater haemolytic activity compared to infection with Hcp-negative isolates. Therefore, presence of T6SS could be indicative of virulent strains meriting further studies to characterize this virulence factor in H. pullorum infection.

PEGylated doped- and undoped-TiO2 nanoparticles for photodynamic Therapy of cancers.

Titanium dioxide has been widely known for its phototoxicity in the environmental context, but little is known for its use in the photodynamic therapy of cancers. Previous studides have shown the hazardous effects of undoped-titanium dioxide nanoparticles (undoped-TiO2 NPs) in the ecosystem; however, it remains to explore the effect of polyethylene glycol (PEG) conjugation and doping of metal and non-metal on the photodynamic activity of TiO2. Here we report the synthesis, characterizations, and applications of doped- and undoped-TiO2 NPs stabilized by PEG in the photodynamic therapy of cancers. Our results demonstrate that in vitro PEG-NPs significantly reduced the survival of human cervical cancer cells (HeLa) upon solar and ultraviolet (UV) radiations. We found that doping of the metal (cobalt) and non-metal (nitrogen) onto TiO2 nanocrystals enhanced the photoactivation of doped-TiO2 NPs in the visible/near infrared (Vis/NIR) region, but these nanocrystals were revealed by cytotoxicity assays to be less potent in killing cancer cells compared to PEGylated undoped-TiO2. The significant photodynamic effect was shown by PEGylated undoped-TiO2 synthesized through the sol-gel method with 75% killing of HeLa cells at 5.5 µg/mL concentrations in exposure to UV or sunlight radiations. In vitro cytotoxicity was measured by Sulforhodamine B (SRB) and 3-(4, 5-Dimethylthiazol-2-Yl)-2,5-Diphenyltetrazolium Bromide (MTT) assays after irradiations with IR, UV, and sunlight for 15-30 minutes (min). All the synthesized NPs were characterized by XRD, AFM, SEM, EDX and DRS chemical analysis. Taken together, our data demonstrate that water-soluble PEGylated TiO2 NPs maybe a good candidate for the photodynamic therapy of cervical cancer cells. Our data propose that the use of PEG surfactant can enhance the potency of already available photochemical therpeutic agents.

Visible light sensitive Ag/TiO2/graphene composite as a potential coating material for control of Campylobacter jejuni.

Infectious diarrhea caused by the food borne pathogen, Campylobacter jejuni, is a major threat to public health worldwide leads high incidence of child mortality each year. In the present study, hydrothermal synthesis of Silver-Graphene-TiO2 nanocomposites along with TiO2, TiO2-Graphene and TiO2-silver nanocomposites was done and the samples were characterized using X-ray diffraction (XRD), tunneling electron microscopy (TEM) and UV-Vis Spectroscopy. Effect of silver and graphene addition on the broad spectrum antibacterial ability of TiO2 was studied under visible light. Moreover, the effects on bacterial survival, membrane integrity, cellular motiltiy and biofilm formation of C. jejuni were also evaluated. A synergetic effect of silver and graphene on Silver-Graphene-TiO2 nanocomposites was observed as indicated by its increased visible light sensitivity and enhanced antibacterial activity under visible light compared to its parent derivatives. Silver-Graphene-TiO2 composites effectively reduced growth and caused leakage of protein and DNA from C. jejuni cell. Atomic Force Microscopy was used to confirm bacterial cell damage. Besides, it also reduced motillity, hydrophobicity and autoaggregation of C. jejuni and showed excellent inhibition of biofilm formation. Furthermore, no significant cytotoxicity of synthesized nanoparticles was observed in human cell lines. We propose that Silver-Graphene-TiO2 composites can be used as effective antimicrobial agents to control the spread of C. jejuni by preventing both bacterial growth and biofilm formation.

Structural basis for the pathogenesis of Campylobacter jejuni Hcp1, a structural and effector protein of the Type VI Secretion System.

The Type VI Secretion System (T6SS) provides enhanced virulence to Campylobacter jejuni and has been associated with a high incidence of bloody diarrhea. The hemolysin-coregulated protein (Hcp)-the hallmark of the T6SS-can act as a structural and effector protein. Unlike other T6SS-harboring bacteria, which possess multiple Hcp proteins each performing different functions, C. jejuni possesses only one Hcp protein, and its structural and functional role has not been elucidated previously. Here, we report the structure and functional studies of Hcp from C. jejuni. We found similarities between the hexameric ring structure of Hcp-Cj and that of Hcp3 from Pseudomonas aeruginosa. Through functional studies, we showed two roles for Hcp-Cj that is, in cytotoxicity toward HepG2 cells and in biofilm formation in C. jejuni. In structure-based mutational analyses, we showed that an Arg-to-Ala mutation at position 30 within the extended loop results in a significant decrease in cytotoxicity, suggesting a role for this loop in binding to the host cell. However, this mutation does not affect its biofilm formation function. Collectively, this study supports the dual role of Hcp-Cj as a structural and effector protein in C. jejuni.

Exploiting in vitro potential and characterization of surface modified Zinc oxide nanoparticles of Isodon rugosus extract: Their clinical potential towards HepG2 cell line and human pathogenic bacteria.

Little is known about biogenically synthesized Zinc oxide nanoparticles (ZnONPs) from Isodon rugosus. Synthesis of metal oxide NPs from essential oil producing medicinal plants results in less harmful side effects to the human population as compared to chemically synthesized NPs. In this article, we report biogenic synthesis of ZnONPs from in vitro derived plantlets and thidiazuron (TDZ) induced callus culture of Isodon rugosus. Synthesized NPs were characterized using UV-spectra, XRD, FTIR, SEM and EDX. Furthermore, the NPs were evaluated for their potential cytotoxic (against HepG2 cell line) and antimicrobial (against drug resistant Staphylococcus epidermidis, Bacillus subtilis, Klebsiella pneumoniae and Pseudomonas aeruginosa) activities. Pure crystalline ZnONPs with hexagonal and triangular shapes were obtained as a result of callus extract (CE) and whole plant extract (WPE), respectively. ZnONPs showed potent cytotoxic and antimicrobial potential. The antimicrobial and cytotoxic activities of ZnONPs were found to be shape and surface bound phytochemicals dependent. CE mediated hexagonal ZnONPs showed superior anti-cancer and antimicrobial activities as compared to WPE mediated triangular shaped ZnONPs. It is concluded that biogenic ZnONPs have incredible potential as theranostic agents and can be adopted as useful drug delivery system in next generation treatment strategies.

Natural products as reservoirs of novel therapeutic agents.

Since ancient times, natural products from plants, animals, microbial and marine sources have been exploited for treatment of several diseases. The knowledge of our ancestors is the base of modern drug discovery process. However, due to the presence of extensive biodiversity in natural sources, the percentage of secondary metabolites screened for bioactivity is low. This review aims to provide a brief overview of historically significant natural therapeutic agents along with some current potential drug candidates. It will also provide an insight into pros and cons of natural product discovery and how development of recent approaches has answered the challenges associated with it.