Satyakam Patnaik

General Reagent Free Route to pH Responsive Polyacryloyl Hydrazide Capped Metal Nanogels for Synergistic Anticancer Therapeutics

Herewith, we report a facile synthesis of pH responsive polyacryloyl hydrazide (PAH) capped silver (Ag) or gold (Au) nanogels for anticancer therapeutic applications. A cost-effective instant synthesis of PAH-Ag or PAH-Au nanoparticles (NPs) possessing controllable particle diameter and narrow size distribution was accomplished by adding AgNO3 or AuCl to the aqueous solution of PAH under ambient conditions without using any additional reagent. PAH possessing carbonyl hydrazide pendant functionality served as both reducing and capping agent to produce and stabilize the NPs. The stability analysis by UV-vis, dynamic light scattering, and transmission electron microscopy techniques suggested that these NPs may be stored in a refrigerator for at least up to 2 weeks with negligible change in conformation. The average hydrodynamic size of PAH-Ag NPs synthesized using 0.2 mmol/L AgNO3 changed from 122 to 226 nm on changing the pH of the medium from 5.4 to 7.4, which is a characteristic property of pH responsive nanogel. Camptothecin (CPT) with adequate loading efficiency (6.3%) was encapsulated in the PAH-Ag nanogels. Under pH 5.4 conditions, these nanogels released 78% of the originally loaded CPT over a period of 70 h. The antiproliferative potential of PAH-Ag-CPT nanogels (at [CPT]=0.6 μg/mL) against MCF-7 breast adeno-carcinoma cells were ∼350% higher compared to that of the free CPT as evidenced by high cellular internalization of these nanogels. Induction of apoptosis in MCF-7 breast adeno-carcinoma cells by PAH-Ag-CPT nanogels was evidenced by accumulation of late apoptotic cell population. Drug along with the PAH-Ag NPs were also encapsulated in a pH responsive hydrogel through in situ gelation at room temperature using acrylic acid as the cross-linker. The resulting hydrogel released quantitative amounts of both drug and PAH-Ag NPs over a period of 16 h. The simplicity of synthesis and ease of drug loading with efficient release render these NPs a viable candidate for various biomedical applications, and moreover this synthetic procedure may be extended to other metal NPs.

Statistical optimization and artificial neural network modeling for acridine orange dye degradation using in-situ synthesized polymer capped ZnO nanoparticles

ZnO NPs were synthesized by a prudent green chemistry approach in presence of polyacrylamide grafted guar gum polymer (pAAm-g-GG) to ensure uniform morphology, and functionality and appraised for their ability to degrade photocatalytically Acridine Orange (AO) dye. These ZnO@pAAm-g-GG NPs were thoroughly characterized by various spectroscopic, XRD and electron microscopic techniques. The relative quantity of ZnO NPs in polymeric matrix has been estimated by spectro-analytical procedure; AAS and TGA analysis. The impact of process parameters viz. NPs dose, contact time and AO dye concentration on percentage photocatalytic degradation of AO dyes were evaluated using multivariate optimizing tools, Response Surface Methodology (RSM) involving Box-Behnken Design (BBD) and Artificial Neural Network (ANN). Congruity of the BBD statistical model was implied by R2 value 0.9786 and F-value 35.48. At RSM predicted optimal condition viz. ZnO@pAAm-g-GG NPs dose of 0.2g/L, contact time of 210min and AO dye concentration 10mg/L, a maximum of 98% dye degradation was obtained. ANOVA indicated appropriateness of the model for dye degradation owing to Prob.>F less than 0.05 for variable parameters. We further, employed three layers feed forward ANN model for validating the BBD process parameters and suitability of our chosen model. The evaluation of Levenberg-Marquardt algorithm (ANN1) and Gradient Descent with adaptive learning rate (ANN2) model employed to scrutinize the best method and found experimental values of AO dye degradation were in close to those with predicated value of ANN 2 modeling with minimum error.

Engineered polymer-supported synthesis of 3'-carboxyalkyl-modified oligonucleotides and their applications in the construction of biochips for diagnosis of the diseases.

An engineered polymer support 5 has been prepared for the solid-phase assembly of 3-carboxyalkyl-modified oligonucleotides using commonly available reagents. A two-step deprotection procedure resulted in the quantitative cleavage of oligonucleotides from the support and removal of the protecting groups from phosphodiesters and exocyclic amino groups of the nucleic bases. The fully deprotected oligomers, obtained in high yield, were desalted and analyzed on RP-HPLC. After characterization by MALDI-TOF, these carboxyalkylated oligonucleotides were immobilized onto the epoxy-functionalized glass microslides to prepare biochips. The performance of these biochips was evaluated under different sets of conditions and then successfully validated by the detection of base mismatches and human infectious disease, bacterial meningitis, caused by N. meningitidis.

Hijacking microglial glutathione by inorganic arsenic impels bystander death of immature neurons through extracellular cystine/glutamate imbalance

Arsenic-induced altered microglial activity leads to neuronal death, but the causative mechanism remains unclear. The present study showed, arsenic-exposed (10u2009μM) microglial (N9) culture supernatant induced bystander death of neuro-2a (N2a), which was further validated with primary microglia and immature neuronal cultures. Results indicated that arsenic-induced GSH synthesis by N9 unfavorably modified the extracellular milieu for N2a by lowering cystine and increasing glutamate concentration. Similar result was observed in N9-N2a co-culture. Co-exposure of arsenic and 250u2009μM glutamate, less than the level (265u2009μM) detected in arsenic-exposed N9 culture supernatant, compromised N2a viability which was rescued by cystine supplementation. Therefore, microglia executes bystander N2a death by competitive inhibition of system Xc- (xCT) through extracellular cystine/glutamate imbalance. We confirmed the role of xCT in mediating bystander N2a death by siRNA inhibition studies. Ex-vivo primary microglia culture supernatant from gestationally exposed mice measured to contain lower cystine and higher glutamate compared to control and N-acetyl cysteine co-treated group. Immunofluorescence staining of brain cryosections from treated group showed more dead immature neurons with no such effect on microglia. Collectively, we showed, in presence of arsenic microglia alters cystine/glutamate balance through xCT in extracellular milieu leading to bystander death of immature neurons.

Curcumin loading potentiates the chemotherapeutic efficacy of selenium nanoparticles in HCT116 cells and Ehrlich’s ascites carcinoma bearing mice

Graphical abstract Figure. No caption available. ABSTRACT The anticancer properties of selenium (Se) and curcumin nanoparticles in solo formulations as well as in combination with other therapeutic agents have been proved time and again. Exploiting this facet of the two, we clubbed their tumoricidal characteristics and designed curcumin loaded Se nanoparticles (Se‐CurNPs) to achieve an enhanced therapeutic effect. We evaluated their therapeutic effects on different cancer cell lines and Ehrlichs ascites carcinoma mouse model. In vitro results showed that Se‐CurNPs were most effective on colorectal carcinoma cells (HCT116) compared to the other cancer cell lines used and possessed pleiotropic anticancer effects. The therapeutic effect on HCT116 was primarily attributed to an elevated level of autophagy and apoptosis as evident from significant up‐regulation of autophagy associated (LC3B‐II) and pro‐apoptotic (Bax) proteins, down‐regulation of anti‐apoptotic (Bcl‐2) protein and Cytochrome c (cyt c) release from mitochondria along with reduced NF&kgr;B signaling and EMT based machineries marked by downregulation of inflammation (NF&kgr;B, phospho‐NF&kgr;B) and epithelial‐mesenchymal transition (CD44, N‐cadherin) associated proteins. In vivo studies on Ehrlichs ascites carcinoma (EAC) mice model indicated that Se‐CurNPs significantly reduced the tumor load and enhanced the mean survival time (days) of tumor‐bearing EAC mice.

Arsenic exposure impels CD4 commitment in thymus and suppress T cell cytokine secretion by increasing regulatory T cells

Arsenic is globally infamous for inducing immunosuppression associated with prevalence of opportunistic infection in exposed population, although the mechanism remains elusive. In this study, we investigate the effect of arsenic exposure on thymocyte lineage commitment and the involvement of regulatory T cells (Treg) in arsenic-induced immunosuppression. Male Balb/c mice were exposed to 0.038, 0.38 and 3.8u2009ppm sodium arsenite for 7, 15 and 30 days through oral gavage. Arsenic exposure promoted CD4 lineage commitment in a dose dependent manner supported by the expression of ThPOK in thymus. Arsenic also increased splenic CD4+ T cells and promoted their differentiation into Treg cells. In parallel,ufeff arsenic exposure induced immunosuppression characterized by low cytokine secretion from splenocytes and increased susceptibility to Mycobacterium fortuitum (M. fortuitum) infection. Therefore, we linked arsenic-induced rise in Treg cells with suppressed Th1 and Th2 related cytokines, which has been reversed by inhibition of Treg cells in-vivo using wortmannin. Other parameters like body weight, kidney and liver function, histoanatomy of thymus and spleen as well as thymocyte and splenocytes viability were unaltered by arsenic exposure. Taken together our findings indicated that environmentally relevant dose of arsenic enhanced differentiation of Treg cells which in turn induce immunosuppression in experimental animals.

Inhibition of Thioredoxin Reductase by Targeted Selenopolymeric Nanocarriers Synergizes the Therapeutic Efficacy of Doxorubicin in MCF7 Human Breast Cancer Cells

Increasing evidence suggests selenium nanoparticles (Se NPs) as potential cancer therapeutic agents and emerging drug delivery carriers, yet, the molecular mechanism of their anticancer activity still remains unclear. Recent studies indicate thioredoxin reductase (TrxR), a selenoenzyme, as a promising target for anticancer therapy. The present study explored the TrxR inhibition efficacy of Se NPs as a plausible factor impeding tumor growth. Hyaluronic acid (HA)-functionalized selenopolymeric nanocarriers (Se@CMHA NPs) were designed wielding chemotherapeutic potential for target specific Doxorubicin (DOX) delivery. Se@CMHA nanocarriers are thoroughly characterized asserting their chemical and physical integrity and possess prolonged stability. DOX-loaded selenopolymeric nanocarriers (Se@CMHA-DOX NPs) exhibited enhanced cytotoxic potential toward human cancer cells compared to free DOX in an equivalent concentration eliciting its selectivity. In first-of-its-kind findings, selenium as Se NPs in these polymeric carriers progressively inhibit TrxR activity, further augmenting the anticancer efficacy of DOX through a synergistic interplay between DOX and Se NPs. Detailed molecular studies on MCF7 cells also established that upon exposure to Se@CMHA-DOX NPs, MCF7 cells endure G2/M cell cycle arrest and p53-mediated caspase-independent apoptosis. To gauge the relevance of the developed nanosystem in in vivo settings, three-dimensional tumor sphere model mimicking the overall tumor environment was also performed, and the results clearly depict the effectiveness of our nanocarriers in reducing tumor activity. These findings are reminiscent of the fact that our Se@CMHA-DOX NPs could be a viable modality for effective cancer chemotherapy.

Sneaky Entry of IFNγ Through Arsenic-Induced Leaky Blood–Brain Barrier Reduces CD200 Expression by Microglial pro-Inflammatory Cytokine

Recent studies showed that neuronal surface protein CD200 plays a key role in the regulation of neuroinflammation. Previously, we showed that arsenic (0.38xa0mg/kg body weight) exposure induces microglial activation and consequently IL-6/TNF-α secretion. This result indicated the possibility of alteration in the expression of CD200. Therefore, the present study was focused on checking arsenic-induced alteration in CD200 expression and revealing the underlying mechanism. Male BALB/c mice were exposed to arsenic (vehicle, 0.038 and 0.38xa0mg/kg body weight) for 60xa0days, and the expression level of CD200 was found to be decreased which was rescued by minocycline (33xa0mg/kg body weight) co-administration. Higher CD68 staining, increased level of IL-6/TNF-α, as well as higher level of IFNγ, were observed in in vivo arsenic-exposed groups. Interestingly, in vitro arsenic exposure could not increase IL-6/TNF-α level in the culture supernatant, whereas, supplementation of IFNγ could mimic the in vivo results. However, arsenic could not induce IFNγ production from brain endothelial cells, microglia, and astrocytes, thereby suggesting the entry of IFNγ through the impaired blood–brain barrier. Evans blue fluorescence in the brain confirms altered blood–brain barrier permeability although no changes were observed in the expression level of tight junction proteins (claudin-5 and occludin). Finally, intracerebral injection of anti-IFNγ neutralizing antibody in arsenic-exposed brain reduced microglia activation (IL-6 and TNF-α and CD68 expression) and subsequently rescued CD200 level. Taken together, the study showed that arsenic-mediated compromised blood–brain barrier is a major driving force to induce microglial IL-6 and TNF-α production through serum IFNγ leading to CD200 downregulation.

Curcumin loaded selenium nanoparticles synergize the anticancer potential of doxorubicin contained in self-assembled, cell receptor targeted nanoparticles

ABSTRACT Doxorubicin (DOX) has been extensively used to treat a wide range of cancers in free and nanotized form. Nanotization of DOX has alleviated its toxicity and efflux‐mediated resistance. However, frequent upregulation of anti‐apoptotic pathways, chemotherapy‐enhanced inflammation, and epithelial‐mesenchymal transition (EMT), present additional aspects of cellular DOX résistance. Nanoparticle‐mediated combination therapy of DOX with additional anticancer agents is expected to offer greater therapeutic benefit by alleviating the overall drug résistance. We synthesized CD44‐targeted DOX loaded nanoparticles (PSHA‐DOXNPs) and evaluated their anticancer efficacy in combination with curcumin loaded selenium nanoparticles (Se‐Cur NPs), previously developed by our group (Kumari et al., 2017). Combination of these nanoparticles (NPs) increased ROS level, decreased mitochondrial membrane potential, induced cell cycle arrest and apoptosis in HCT116 cells. This combination decreased the expressions of NF&kgr;B, Phospho‐NF&kgr;B, EMT‐metastasis‐associated proteins (Snail, Vimentin, N‐cadherin, CD44, MMP‐2 and MMP‐9), autophagy‐associated proteins (Beclin‐1 and LC‐3BII), as well as anti‐apoptotic protein Bcl‐2, increased the expression of pro‐apoptotic protein Bax, and increased cyt c release, which indicated decrease in inflammation, metastasis, and autophagy with increase in apoptosis. Moreover, the combination of NPs decreased tumor burden and increased survival of Ehrlich’s ascites carcinoma (EAC)‐bearing mice.

Predictive modeling and validation of arsenite removal by a one pot synthesized bioceramic buttressed manganese doped iron oxide nanoplatform

In the present study, a series of bioceramic capped manganese doped superparamagnetic iron oxide (SPIONs) nanoparticles (mHAP NPs) were synthesized by one pot in situ reduction. The aging of the bioceramic on the SPIONs was optimized to achieve variation in functionality, morphology, magnetic susceptibility, shape and size of the NPs and ultimately remediation effectiveness of arsenite; As(III). Results indicate that among various synthesized NPs, the 6 h aged mHAP NPs with 27 emu magnetic susceptibility, 57.30 m2 g−1 surface area and 75.64 A average pore diameter offer the best option as an adsorbent for posthaste removal of As(III) from synthetically spiked water. Further, predictive modeling using response surface based Central Composite Design (CCD) was applied to achieve and optimize process parameters for the removal of As(III) by mHAP NPs keeping variable operational parameters to a minimum in batch experiments. The individual and collective effect of four process parameters, i.e. pH, mHAP NP dose, contact time and initial As(III) concentration on As(III) adsorption were studied. The results from statistical design signify that, with 0.2 g L−1 of above mHAP NPs adsorbent dose, 98% As(III) (initial concentration 0.1–0.4 mg L−1) removal was possible in 210 min at pH 6.5 which is well within the prescribed value as per WHO guidelines. The adsorption process of As(III) onto mHAP NPs showed excellent correlation with a Langmuir isotherm with a maximum adsorption capacity of 12.0 mg g−1. Kinetic and thermodynamic studies reveal pseudo-second-order kinetics with an exothermic and spontaneous adsorption of As(III) on the synthesized adsorbent. Cyclic regeneration of mHAP NPs indicated positive impact in remediation technology at low production cost.