Pallab Sanpui | Indian Institute of Technology Guwahati (original) (raw)

Papers by Pallab Sanpui

Nanotechnology in Modern Animal Biotechnology, 2019

Gold nanostructures – due to their ease of synthesis and functionalization, unique tunable optica... more Gold nanostructures – due to their ease of synthesis and functionalization, unique tunable optical properties and stability – are widely being explored for their applicability in sensing, diagnostics, drug delivery and cancer therapy. Engineering different gold nanostructures with varying shape and size enable us to tune the localized surface plasmon resonance (LSPR) peak from visible to near infra-red (NIR) region of the electromagnetic spectrum, which can be exploited for biomedical applications. For example, gold nanorods show two peaks in their extinction spectra, corresponding to the transverse and longitudinal mode of surface electron oscillation on the influence of light. Similarly, other gold nanostructures with different morphologies like nanoshells, nanorattles, nanostars, nanopopcorns, nanoaggregates, etc. too have extinction band in the NIR region, which has a better tissue penetration depth. This strong optical absorbance of the gold nanostructures, especially in the NIR region and subsequent dissipation of energy in a nonradiative process can suitably be exploited for plasmonic photothermal therapy (PPTT). In this regard, NIR light stimulated heat can be generated from the targeted gold nanostructures and this can potentially be used to kill cancer cells. The present chapter discusses about the design and applicability of gold based nanostructures of different morphologies for efficient photothermal therapy.

ACS Applied Bio Materials, 2019

Herein, a stimulus-responsive theranostic nanosystem comprising gold nanorattles (AuNRTs), having... more Herein, a stimulus-responsive theranostic nanosystem comprising gold nanorattles (AuNRTs), having a solid octahedron core and thin porous cubic shell, encapsulated within chitosan nanocarriers (CS-AuNRT) has been reported. Due to the plasmonic AuNRTs, CS-AuNRT demonstrated unique features of near infrared (NIR) absorbance and accessible intrinsic electromagnetic "hot spots" arising due to coupling of inner solid core and outer porous shell. These properties enabled CS-AuNRTs to be used for NIR-responsive drug delivery, photothermal therapy, and surface enhanced Raman scattering (SERS) based bioimaging. Following loading of chemotherapeutic drug doxorubicin (DOX) within AuNRTs along with a phase changing material (PCM), application of NIR irradiation resulted in photothermal melting of the PCM and simultaneous payload release in the surrounding medium. Although being nontoxic themselves, CS-AuNRTs with or without loaded DOX could mount significant cell death in breast cancer cell line (MCF-7) in the presence of NIR light as external stimulus. The oxidative stress generated by DOX-loaded and empty CS-AuNRTs upon NIR irradiation were confirmed by flowcytometric determination of intracellular reactive oxygen species (ROS). Further, the ROS-led induction of apoptosis in treated MCF-7 cells was established from characteristic nuclear fragmentation, morphological changes and membrane blebbing as observed through confocal fluorescence and scanning electron microscopy. Thus, with NIR responsive chemo-photothermal therapy and SERS based bioimaging, the present nanocarrier system holds potential for cancer theranostics.

ACS Applied Bio Materials, 2019

Herein, a membrane-coated nanocarrier for codelivery of chemotherapeutic agents, curcumin (Cur) a... more Herein, a membrane-coated nanocarrier for codelivery of chemotherapeutic agents, curcumin (Cur) and the hypoxia-activated molecule, tirapazamine (TPZ), has been developed. Cur and TPZ were loaded into biodegradable poly(lactic-co-glycolic acid) nanoparticles (PLGA NPs) and finally coated with red blood cell (RBC) membrane by an extrusion process. Characterization of drug-loaded membrane-coated NPs (Cur+TPZ@RB) by dynamic light scattering, TEM and FESEM analyses showed that the NPs were of 105 nm size with a surface charge of −31 mV. Experimental results demonstrated long-term stability, biocompatibility and efficient cellular internalization (primarily through caveolin mediated pathway) of the Cur+TPZ@RB. Antiproliferative studies on 2D monolayer as well as hypoxic 3D multicellular spheroids (MCS) confirmed that the drug-loaded NPs were more potent than free drugs, inducing apoptosis via generation of reactive oxygen species and consequent DNA damage. Furthermore, the reduced cell migration in the scratch...

ACS Biomaterials Science & Engineering, 2019

Combination chemotherapy, where drugs with a non-overlapping mode of actions achieve better effic... more Combination chemotherapy, where drugs with a non-overlapping mode of actions achieve better efficacy at lower doses with reduced dose-dependent side effects, holds promise for complete remission of the tumor. Herein, we report a combination therapeutic module comprised of the folic acid receptor (FAR)-targeted SeNPs (FA-SeNPs) and MAPK pathway inhibitor PD98059 (PD98). While aberrant signaling leading to an uncontrolled proliferation in BRAF-mutation bearing cancer cells including MDAMB231 (breast cancer) and A375 (melanoma) cells was inhibited by PD98, high expression of FAR by these cells also led to selective internalization of FA-SeNPs. Consequently, the combination treatment of PD98 and FA-SeNPs demonstrated synergistic antiproliferative efficacy in MDAMB231 and A375 cells involving apoptotic mode of cell death. The selective nature of the present combination module was supported by the low off-target response in L132 non-cancerous lung cells. Moreover, the size of the three-dimensional MDAMB231 spheroids was successfully reduced because of the combination therapy projecting its potential in eradicating tumor in vivo.

Nanomedicine (London, England), 2017

To develop selenium nanoparticles (SeNPs)-based delivery systems for paclitaxel (PTX) and assess ... more To develop selenium nanoparticles (SeNPs)-based delivery systems for paclitaxel (PTX) and assess their antiproliferative efficacy against cancer cells in vitro with potential mechanistic insight. Pluronic F-127 stabilized SeNPs were prepared and characterized. Effects of PTX-loaded SeNPs on lung (A549), breast (MCF7), cervical (HeLa) and colon (HT29) cancer cells were studied by viability assay complemented with flow-cytometric analyses of cell cycle, apoptosis, mitochondrial membrane potential, intracellular reactive oxygen species and caspase activity. PTX-loaded SeNPs demonstrated significant antiproliferative activity against cancer cells. Cell cycle analyses of PTX-SeNPs treated cells established G2/M phase arrest in a dose-dependent manner leading to apoptosis. Further investigation revealed disruption of mitochondrial membrane potential orchestrated with induction of reactive oxygen species leading to the activation of caspases, key players of apoptotic cell death. Efficient ...

International journal of biological macromolecules, Jan 2, 2017

Granulocyte macrophage colony stimulating factor (GMCSF), a therapeutically important cytokine th... more Granulocyte macrophage colony stimulating factor (GMCSF), a therapeutically important cytokine that helps in the proliferation of macrophages, was recombinantly expressed in E. coli BL21 and purified as a GST-tagged protein. Cell viability assay demonstrated significant enhancement in proliferation of RAW 264.7 (murine macrophage) in presence of GMCSF. In vitro activation of macrophages was carried out by lipopolysaccharide (LPS) or pyrogallol and probed by the generation of reactive oxygen species (ROS). Following the induction of apoptosis in A549 lung cancer cells with anticancer drug cisplatin (at 25μM), apoptotic cancer cells were effectively phagocytosed by the recombinant GMCSF-treated and exogenously activated RAW 264.7 cells as observed in fluorescence microscopic images. The current findings attribute possible role of GMCSF as adjuvant in scavenging treated cancer cells.

Bioengineered, Jan 28, 2017

Phytaspase, a plant serine protease, has been demonstrated to play an important role in the progr... more Phytaspase, a plant serine protease, has been demonstrated to play an important role in the programmed cell death of various plants. Phytaspase is synthesized as an inactive proenzyme containing an N-terminal signal peptide followed by a pro-domain and a mature protease catalytic domain. Pre-prophytaspase autocatalytically processes itself into a pro-domain and an active mature phytaspase enzyme. We have recently demonstrated the successful expression of mature phytaspase from tobacco in a bacterial system. Herein, we focus on the expression of pre-prophytaspase as a GST-tag fusion and on its purification by affinity chromatography.

International Journal of Biological Macromolecules, 2016

In silico studies with uracil phosphoribosyltransferase from Arabidopsis thaliana (AtUPRT) reveal... more In silico studies with uracil phosphoribosyltransferase from Arabidopsis thaliana (AtUPRT) revealed its lower binding energies for uracil and 5-fluorouracil (5-FU) as compared to those of bacterial UPRT indicating the prospective of AtUPRT in gene therapy implications. Hence, AtUPRT was cloned and stably expressed in cervical cancer cells (HeLa) to investigate the effect of prodrug 5-FU on these transfected cancer cells. The treatment of AtUPRT-expressing HeLa (HeLa-UPP) cells with 5-FU for 72h resulted in significant decrease in cell viability. Moreover, 5-FU was observed to induce apoptosis and perturb mitochondrial membrane potential in HeLa-UPP cells. While cell cycle analysis revealed significant S-phase arrest as result of 5-FU treatment in HeLa-UPP cells, quantitative gene expression analysis demonstrated simultaneous upregulation of important cell cycle related genes, cyclin D1 and p21. The survival fractions of non-transfected, vector-transfected and AtUPRT-transfected HeLa cells, following 5-FU treatment, were calculated to be 0.425, 0.366 and 0.227, respectively.

ACS Applied Nano Materials, 2018

Fabrication of novel magnetofluorescent nanoparticles by complexation of zinc ions present on the... more Fabrication of novel magnetofluorescent nanoparticles by complexation of zinc ions present on the surface of zinc ferrite nanoparticle (ZnFe2O4 NP) with 8-hydroxy-2quinolinecarboxaldehyde (HQCald) is reported. The as prepared HQCald-complexed ZnFe2O4 NPs showed good quantum yield (3.62%), high photostability, considerable excited state lifetime (5.31 ns) and high saturation magnetization (12.7 emu g-1). These magnetofluorescent nanoparticles demonstrated bioimaging capability both at the ensemble and single particle levels, and in vitro magnetic targeting. Moreover, the pronounced anti-proliferative efficacy of these

ACS Applied Bio Materials, 2018

Herein, we report the fabrication of a novel class of magnetofluorescent theranostic nanoparticle... more Herein, we report the fabrication of a novel class of magnetofluorescent theranostic nanoparticles (MFTNPs) based on 'surface-complexation' of zinc ferrite (ZnFe2O4) NPs with 8hydroxyquinoline. The potential of these MFTNPs in fluorescence-based bioimaging of different cancer cells was successfully demonstrated. The superparamagnetic behavior of the MFTNPs was exploited effectively in magnetic targeting in vitro. Finally, a well-known hydrophobic antimalarial and prospective anti-cancer drug artemisinin was efficiently loaded into MFTNPs. Artemisinin loaded MFTNPs were observed to induce superior anti-proliferative response, as compared to free drug, in cancer cells in a synergistic mechanism with combination index of 0.1 or less.

Chem. Commun., 2017

Biomimetically crystallized zinc phosphate nanoparticles act as host to protein fragment-stabiliz... more Biomimetically crystallized zinc phosphate nanoparticles act as host to protein fragment-stabilized Au nanoclusters for efficient bioimaging.

ACS Applied Materials & Interfaces, 2016

We report a simple approach for fabricating plasmonic and magneto-luminescent multifunctional nan... more We report a simple approach for fabricating plasmonic and magneto-luminescent multifunctional nanocarriers (MFNCs) by assembling gold nanorods, iron oxide nanoparticles and gold nanoclusters within BSA nanoparticles. The MFNCs showed self-tracking capability through single and two photon imaging, and the potential for magnetic targeting in vitro. Appreciable T2-relaxivity exhibited by the MFNCs indicated favorable conditions for magnetic resonance imaging. In addition to successful plasmonic-photothermal therapy of cancer cells (HeLa) in vitro, the MFNCs demonstrated efficient loading and delivery of doxorubicin to HeLa cells leading to significant cell death. The present MFNCs with their multimodal imaging and therapeutic capabilities could be eminent candidates for cancer theranostics.

ACS Applied Bio Materials, 2019

Two-dimensional molybdenum disulfide (MoS2) based nanosheets functionalized or loaded with an ant... more Two-dimensional molybdenum disulfide (MoS2) based nanosheets functionalized or loaded with an antimicrobial agent have recently attracted attention as highly efficient antibacterial agent. MoS2 sheets act as the photothermal transducers in inducing bacterial cell death on impingement of NIR radiation or enabled cell inactivation by wrapping around the cells. However, the intrinsic ability of MoS2 to act as an effective antibacterial agent without the use of any external stimuli or antimicrobial agent is still not well explored. This study provides a detailed mechanism of antibacterial action of chitosan exfoliated MoS2 nanosheets (CS-MoS2) by deciphering the key events happening both at the membrane surface and inside the bacteria as a result of interaction of bacterial cells with the nanosheets. A simple, green, one-step process was employed for synthesizing stable and positively charged MoS2 nanosheets. The prepared nanosheets showed excellent bactericidal activity against both Gram-positive (MIC = 90 μg/mL, MBC = 120 μg/mL) and Gram-negative bacteria (MIC = 30 μg/mL, MBC = 60 μg/mL). Investigations into deciphering the mechanism of action revealed that the CS-MoS2 nanosheets interacted strongly with the bacterial cells through electrostatic interactions and caused rapid depolarization of the membranes through dent formations. On account of strong van der Waals and electrostatic forces occurring between the CS-MoS2 nanosheets and membrane phospholipid molecules, deepening of dents occurred, which resulted in complete membrane disruption and leakage of cytoplasmic contents. This led to inactivation of the bacterial respiratory pathway through inhibition of dehydrogenase enzymes and induced metabolic arrest in the cells. Simultaneously, disruption of the antioxidant defense system of the cells by increased levels of intracellular ROS subjected the cells to oxidative damage and added to the overall bactericidal action. The nanosheets also displayed antibiofilm properties and were found to be compatible with mammalian cells even at high concentrations.

ACS Applied Bio Materials

We report the fabrication of a plasmonic magneto-luminescent multifunctional nanocarrier (PML-MF ... more We report the fabrication of a plasmonic magneto-luminescent multifunctional nanocarrier (PML-MF nanocarrier) by lysozyme-mediated agglomeration of gold-coated iron oxide nanoparticles (IO@AuNPs) and subsequent coating of these agglomerates with BSA-stabilized gold nanoclusters (BSA-AuNCs). The agglomeration-mediated enhancement of plasmonic absorbance at the NIR biological window helped in plasmonic photothermal therapy (PPTT) by PML-MF nanocarriers. PML-MF nanocarriers demonstrated excellent in vitro bioimaging and magnetic targeting capabilities due to the strong photoluminance and superparamagnetism of the constituent AuNCs and IO@AuNPs, respectively. Moreover, these nanocarriers showed the successful loading and delivery of doxorubicin to cancer cells with a significant killing efficiency that could be synergistically improved by combining with PPTT.

Colloids and Surfaces B: Biointerfaces, 2017

The objective of this work was to develop a simple surface modification technique using keratin d... more The objective of this work was to develop a simple surface modification technique using keratin derived from human hair for efficient cardiomyogenic lineage commitment of human mesenchymal stem cells (hMSCs). Keratin was extracted from discarded human hair containing both the acidic and basic components along with the heterodimers. The extracted keratin was adsorbed to conventional tissue culture polystyrene surfaces at different concentration. Keratin solution of 500μg/ml yielded a well coated layer of 12±1nm thickness with minimal agglomeration. The keratin coated surfaces promoted cell attachment and proliferation. Large increases in the mRNA expression of known cardiomyocyte genes such as cardiac actinin, cardiac troponin and β-myosin heavy chain were observed. Immunostaining revealed increased expression of sarcomeric α-actinin and tropomyosin whereas Western blots confirmed higher expression of tropomyosin and myocyte enhancer factor 2C in cells on the keratin coated surface than on the non-coated surface. Keratin promoted DNA demethylation of the Atp2a2 and Nkx2.5 genes thereby elucidating the importance of epigenetic changes as a possible molecular mechanism underlying the increased differentiation. A global gene expression analysis revealed a significant alteration in the expression of genes involved in pathways associated in cardiomyogenic commitment including cytokine and chemokine signaling, cell-cell and cell-matrix interactions, Wnt signaling, MAPK signaling, TGF-β signaling and FGF signaling pathways among others. Thus, adsorption of keratin offers a facile and affordable yet potent route for inducing cardiomyogenic lineage commitment of stem cells with important implications in developing xeno-free strategies in cardiovascular regenerative medicine.

ACS Applied Nano Materials

Herein, a green method for the development of a novel biodegradable silver nanoparticles (NPs) im... more Herein, a green method for the development of a novel biodegradable silver nanoparticles (NPs) impregnated alginate–chitosan-blended nanocarrier (Ag NPs–Alg–Chi NC) is reported. The synthesis of Ag NPs–Alg–Chi NC is based on the polyelectrolyte complex formation between alginate and chitosan. The composite NC is characterized by ultraviolet–visible spectroscopy, transmission electron microscopy, scanning electron microscopy (SEM), Fourier transform infrared spectroscopy, and X-ray diffraction. The Ag NPs in the NC are found to elicit anticell proliferative effect on refractory U87MG (human glioblastoma) cells at IC 50 of 2.4 μ g mL − 1 for Ag NPs. The cell cycle analysis shows extensive DNA damage. Elevation in reactive oxygen species level indicates induction of oxidative stress in treated cells. Mitochondrial dysfunction in cell death is evident from the depolarization of mitochondrial membrane potential (Δ Ψ m). Fluorescence and SEM images of the treated cells reveal nuclear and morphological changes characteristic of apoptosis, which is further confi rmed by TUNEL assay. The induction of apoptosis at low concentration of Ag NPs present in Ag NPs–Alg–Chi NC in comparison with free Ag

A new and simple ecofriendly method for the synthesis of silver nanoparticles (Ag NPs) using a na... more A new and simple ecofriendly method for the synthesis of silver nanoparticles (Ag NPs) using a natural biopolymer, sodium alginate as both reducing and stabilizing agent is reported. The synthesized NPs were characterized using UV-Vis spectroscopy, transmission electron microscopy (TEM) and selected area electron diffraction pattern (SAED). The alginate capped NPs (Alg–Ag NPs) were found to be antibacterial. The Alg–Ag NPs were blended with varying amounts of chitosan to form polyelectrolyte complex that was cast into stable films. The films were characterized by field emission scanning electron microscopy (FESEM), optical microscopy, Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). The water uptake and mechanical properties of the films were also studied. The blended film demonstrated excellent antibacterial activity against both Gram negative and Gram positive bacteria with more activity against Gram positive bacteria. Thus, the developed films have a potential to be used for various antibacterial applications in biotechnology and biomedical fields.

Water dispersible zinc sulfide quantum dots (ZnS QDs) with an average diameter of 2.9 nm were syn... more Water dispersible zinc sulfide quantum dots (ZnS QDs) with an average diameter of 2.9 nm were synthesized in an environment friendly method using chitosan as stabilizing agent. These nanocrystals displayed characteristic absorption and emission spectra having an absorbance edge at 300 nm and emission maxima (λ emission) at 427 nm. Citrate-capped silver nanoparticles (Ag NPs) of ca. 37-nm diameter were prepared by modified Turkevich process.

Owing to the ever-increasing applications, glittered with astonishing success of gold nanoparticl... more Owing to the ever-increasing applications, glittered with astonishing success of gold nanoparticles (Au NPs) in biomedical research as diagnostic and therapeutic agents, the study of Au NP–protein interaction seems critical for maximizing their theranostic efficiency, and thus demands comprehensive understanding. The mutual interaction of Au NPs and proteins at physiological conditions may result in the aggregation of protein, which can ultimately lead to the formation of Au NP–protein agglomerates. In the present article, we try to appreciate the plausible steps involved in the Au NP-induced aggregation of proteins and also the importance of the proteins' three-dimensional structures in the process. The Au NP–protein agglomerates can potentially be exploited for efficient loading and subsequent release of various therapeutically important molecules, including anticancer drugs, with the unique opportunity of incorporating hydrophilic as well as hydrophobic drugs in the same nanocarrier system. Moreover, the Au NP–protein agglomerates can act as 'self-diagnostic' systems, allowing investigation of the confor-mational state of the associated protein(s) as well as the protein–protein or protein–Au NP interaction within the agglomerates. Furthermore, the potential of these Au NP–protein agglomerates as a novel platform for multifunctional theranostic application along with exciting future-possibilities is highlighted here.

Nanotechnology in Modern Animal Biotechnology, 2019

Gold nanostructures – due to their ease of synthesis and functionalization, unique tunable optica... more Gold nanostructures – due to their ease of synthesis and functionalization, unique tunable optical properties and stability – are widely being explored for their applicability in sensing, diagnostics, drug delivery and cancer therapy. Engineering different gold nanostructures with varying shape and size enable us to tune the localized surface plasmon resonance (LSPR) peak from visible to near infra-red (NIR) region of the electromagnetic spectrum, which can be exploited for biomedical applications. For example, gold nanorods show two peaks in their extinction spectra, corresponding to the transverse and longitudinal mode of surface electron oscillation on the influence of light. Similarly, other gold nanostructures with different morphologies like nanoshells, nanorattles, nanostars, nanopopcorns, nanoaggregates, etc. too have extinction band in the NIR region, which has a better tissue penetration depth. This strong optical absorbance of the gold nanostructures, especially in the NIR region and subsequent dissipation of energy in a nonradiative process can suitably be exploited for plasmonic photothermal therapy (PPTT). In this regard, NIR light stimulated heat can be generated from the targeted gold nanostructures and this can potentially be used to kill cancer cells. The present chapter discusses about the design and applicability of gold based nanostructures of different morphologies for efficient photothermal therapy.

ACS Applied Bio Materials, 2019

Herein, a stimulus-responsive theranostic nanosystem comprising gold nanorattles (AuNRTs), having... more Herein, a stimulus-responsive theranostic nanosystem comprising gold nanorattles (AuNRTs), having a solid octahedron core and thin porous cubic shell, encapsulated within chitosan nanocarriers (CS-AuNRT) has been reported. Due to the plasmonic AuNRTs, CS-AuNRT demonstrated unique features of near infrared (NIR) absorbance and accessible intrinsic electromagnetic "hot spots" arising due to coupling of inner solid core and outer porous shell. These properties enabled CS-AuNRTs to be used for NIR-responsive drug delivery, photothermal therapy, and surface enhanced Raman scattering (SERS) based bioimaging. Following loading of chemotherapeutic drug doxorubicin (DOX) within AuNRTs along with a phase changing material (PCM), application of NIR irradiation resulted in photothermal melting of the PCM and simultaneous payload release in the surrounding medium. Although being nontoxic themselves, CS-AuNRTs with or without loaded DOX could mount significant cell death in breast cancer cell line (MCF-7) in the presence of NIR light as external stimulus. The oxidative stress generated by DOX-loaded and empty CS-AuNRTs upon NIR irradiation were confirmed by flowcytometric determination of intracellular reactive oxygen species (ROS). Further, the ROS-led induction of apoptosis in treated MCF-7 cells was established from characteristic nuclear fragmentation, morphological changes and membrane blebbing as observed through confocal fluorescence and scanning electron microscopy. Thus, with NIR responsive chemo-photothermal therapy and SERS based bioimaging, the present nanocarrier system holds potential for cancer theranostics.

ACS Applied Bio Materials, 2019

Herein, a membrane-coated nanocarrier for codelivery of chemotherapeutic agents, curcumin (Cur) a... more Herein, a membrane-coated nanocarrier for codelivery of chemotherapeutic agents, curcumin (Cur) and the hypoxia-activated molecule, tirapazamine (TPZ), has been developed. Cur and TPZ were loaded into biodegradable poly(lactic-co-glycolic acid) nanoparticles (PLGA NPs) and finally coated with red blood cell (RBC) membrane by an extrusion process. Characterization of drug-loaded membrane-coated NPs (Cur+TPZ@RB) by dynamic light scattering, TEM and FESEM analyses showed that the NPs were of 105 nm size with a surface charge of −31 mV. Experimental results demonstrated long-term stability, biocompatibility and efficient cellular internalization (primarily through caveolin mediated pathway) of the Cur+TPZ@RB. Antiproliferative studies on 2D monolayer as well as hypoxic 3D multicellular spheroids (MCS) confirmed that the drug-loaded NPs were more potent than free drugs, inducing apoptosis via generation of reactive oxygen species and consequent DNA damage. Furthermore, the reduced cell migration in the scratch...

ACS Biomaterials Science & Engineering, 2019

Combination chemotherapy, where drugs with a non-overlapping mode of actions achieve better effic... more Combination chemotherapy, where drugs with a non-overlapping mode of actions achieve better efficacy at lower doses with reduced dose-dependent side effects, holds promise for complete remission of the tumor. Herein, we report a combination therapeutic module comprised of the folic acid receptor (FAR)-targeted SeNPs (FA-SeNPs) and MAPK pathway inhibitor PD98059 (PD98). While aberrant signaling leading to an uncontrolled proliferation in BRAF-mutation bearing cancer cells including MDAMB231 (breast cancer) and A375 (melanoma) cells was inhibited by PD98, high expression of FAR by these cells also led to selective internalization of FA-SeNPs. Consequently, the combination treatment of PD98 and FA-SeNPs demonstrated synergistic antiproliferative efficacy in MDAMB231 and A375 cells involving apoptotic mode of cell death. The selective nature of the present combination module was supported by the low off-target response in L132 non-cancerous lung cells. Moreover, the size of the three-dimensional MDAMB231 spheroids was successfully reduced because of the combination therapy projecting its potential in eradicating tumor in vivo.

Nanomedicine (London, England), 2017

To develop selenium nanoparticles (SeNPs)-based delivery systems for paclitaxel (PTX) and assess ... more To develop selenium nanoparticles (SeNPs)-based delivery systems for paclitaxel (PTX) and assess their antiproliferative efficacy against cancer cells in vitro with potential mechanistic insight. Pluronic F-127 stabilized SeNPs were prepared and characterized. Effects of PTX-loaded SeNPs on lung (A549), breast (MCF7), cervical (HeLa) and colon (HT29) cancer cells were studied by viability assay complemented with flow-cytometric analyses of cell cycle, apoptosis, mitochondrial membrane potential, intracellular reactive oxygen species and caspase activity. PTX-loaded SeNPs demonstrated significant antiproliferative activity against cancer cells. Cell cycle analyses of PTX-SeNPs treated cells established G2/M phase arrest in a dose-dependent manner leading to apoptosis. Further investigation revealed disruption of mitochondrial membrane potential orchestrated with induction of reactive oxygen species leading to the activation of caspases, key players of apoptotic cell death. Efficient ...

International journal of biological macromolecules, Jan 2, 2017

Granulocyte macrophage colony stimulating factor (GMCSF), a therapeutically important cytokine th... more Granulocyte macrophage colony stimulating factor (GMCSF), a therapeutically important cytokine that helps in the proliferation of macrophages, was recombinantly expressed in E. coli BL21 and purified as a GST-tagged protein. Cell viability assay demonstrated significant enhancement in proliferation of RAW 264.7 (murine macrophage) in presence of GMCSF. In vitro activation of macrophages was carried out by lipopolysaccharide (LPS) or pyrogallol and probed by the generation of reactive oxygen species (ROS). Following the induction of apoptosis in A549 lung cancer cells with anticancer drug cisplatin (at 25μM), apoptotic cancer cells were effectively phagocytosed by the recombinant GMCSF-treated and exogenously activated RAW 264.7 cells as observed in fluorescence microscopic images. The current findings attribute possible role of GMCSF as adjuvant in scavenging treated cancer cells.

Bioengineered, Jan 28, 2017

Phytaspase, a plant serine protease, has been demonstrated to play an important role in the progr... more Phytaspase, a plant serine protease, has been demonstrated to play an important role in the programmed cell death of various plants. Phytaspase is synthesized as an inactive proenzyme containing an N-terminal signal peptide followed by a pro-domain and a mature protease catalytic domain. Pre-prophytaspase autocatalytically processes itself into a pro-domain and an active mature phytaspase enzyme. We have recently demonstrated the successful expression of mature phytaspase from tobacco in a bacterial system. Herein, we focus on the expression of pre-prophytaspase as a GST-tag fusion and on its purification by affinity chromatography.

International Journal of Biological Macromolecules, 2016

In silico studies with uracil phosphoribosyltransferase from Arabidopsis thaliana (AtUPRT) reveal... more In silico studies with uracil phosphoribosyltransferase from Arabidopsis thaliana (AtUPRT) revealed its lower binding energies for uracil and 5-fluorouracil (5-FU) as compared to those of bacterial UPRT indicating the prospective of AtUPRT in gene therapy implications. Hence, AtUPRT was cloned and stably expressed in cervical cancer cells (HeLa) to investigate the effect of prodrug 5-FU on these transfected cancer cells. The treatment of AtUPRT-expressing HeLa (HeLa-UPP) cells with 5-FU for 72h resulted in significant decrease in cell viability. Moreover, 5-FU was observed to induce apoptosis and perturb mitochondrial membrane potential in HeLa-UPP cells. While cell cycle analysis revealed significant S-phase arrest as result of 5-FU treatment in HeLa-UPP cells, quantitative gene expression analysis demonstrated simultaneous upregulation of important cell cycle related genes, cyclin D1 and p21. The survival fractions of non-transfected, vector-transfected and AtUPRT-transfected HeLa cells, following 5-FU treatment, were calculated to be 0.425, 0.366 and 0.227, respectively.

ACS Applied Nano Materials, 2018

Fabrication of novel magnetofluorescent nanoparticles by complexation of zinc ions present on the... more Fabrication of novel magnetofluorescent nanoparticles by complexation of zinc ions present on the surface of zinc ferrite nanoparticle (ZnFe2O4 NP) with 8-hydroxy-2quinolinecarboxaldehyde (HQCald) is reported. The as prepared HQCald-complexed ZnFe2O4 NPs showed good quantum yield (3.62%), high photostability, considerable excited state lifetime (5.31 ns) and high saturation magnetization (12.7 emu g-1). These magnetofluorescent nanoparticles demonstrated bioimaging capability both at the ensemble and single particle levels, and in vitro magnetic targeting. Moreover, the pronounced anti-proliferative efficacy of these

ACS Applied Bio Materials, 2018

Herein, we report the fabrication of a novel class of magnetofluorescent theranostic nanoparticle... more Herein, we report the fabrication of a novel class of magnetofluorescent theranostic nanoparticles (MFTNPs) based on 'surface-complexation' of zinc ferrite (ZnFe2O4) NPs with 8hydroxyquinoline. The potential of these MFTNPs in fluorescence-based bioimaging of different cancer cells was successfully demonstrated. The superparamagnetic behavior of the MFTNPs was exploited effectively in magnetic targeting in vitro. Finally, a well-known hydrophobic antimalarial and prospective anti-cancer drug artemisinin was efficiently loaded into MFTNPs. Artemisinin loaded MFTNPs were observed to induce superior anti-proliferative response, as compared to free drug, in cancer cells in a synergistic mechanism with combination index of 0.1 or less.

Chem. Commun., 2017

Biomimetically crystallized zinc phosphate nanoparticles act as host to protein fragment-stabiliz... more Biomimetically crystallized zinc phosphate nanoparticles act as host to protein fragment-stabilized Au nanoclusters for efficient bioimaging.

ACS Applied Materials & Interfaces, 2016

We report a simple approach for fabricating plasmonic and magneto-luminescent multifunctional nan... more We report a simple approach for fabricating plasmonic and magneto-luminescent multifunctional nanocarriers (MFNCs) by assembling gold nanorods, iron oxide nanoparticles and gold nanoclusters within BSA nanoparticles. The MFNCs showed self-tracking capability through single and two photon imaging, and the potential for magnetic targeting in vitro. Appreciable T2-relaxivity exhibited by the MFNCs indicated favorable conditions for magnetic resonance imaging. In addition to successful plasmonic-photothermal therapy of cancer cells (HeLa) in vitro, the MFNCs demonstrated efficient loading and delivery of doxorubicin to HeLa cells leading to significant cell death. The present MFNCs with their multimodal imaging and therapeutic capabilities could be eminent candidates for cancer theranostics.

ACS Applied Bio Materials, 2019

Two-dimensional molybdenum disulfide (MoS2) based nanosheets functionalized or loaded with an ant... more Two-dimensional molybdenum disulfide (MoS2) based nanosheets functionalized or loaded with an antimicrobial agent have recently attracted attention as highly efficient antibacterial agent. MoS2 sheets act as the photothermal transducers in inducing bacterial cell death on impingement of NIR radiation or enabled cell inactivation by wrapping around the cells. However, the intrinsic ability of MoS2 to act as an effective antibacterial agent without the use of any external stimuli or antimicrobial agent is still not well explored. This study provides a detailed mechanism of antibacterial action of chitosan exfoliated MoS2 nanosheets (CS-MoS2) by deciphering the key events happening both at the membrane surface and inside the bacteria as a result of interaction of bacterial cells with the nanosheets. A simple, green, one-step process was employed for synthesizing stable and positively charged MoS2 nanosheets. The prepared nanosheets showed excellent bactericidal activity against both Gram-positive (MIC = 90 μg/mL, MBC = 120 μg/mL) and Gram-negative bacteria (MIC = 30 μg/mL, MBC = 60 μg/mL). Investigations into deciphering the mechanism of action revealed that the CS-MoS2 nanosheets interacted strongly with the bacterial cells through electrostatic interactions and caused rapid depolarization of the membranes through dent formations. On account of strong van der Waals and electrostatic forces occurring between the CS-MoS2 nanosheets and membrane phospholipid molecules, deepening of dents occurred, which resulted in complete membrane disruption and leakage of cytoplasmic contents. This led to inactivation of the bacterial respiratory pathway through inhibition of dehydrogenase enzymes and induced metabolic arrest in the cells. Simultaneously, disruption of the antioxidant defense system of the cells by increased levels of intracellular ROS subjected the cells to oxidative damage and added to the overall bactericidal action. The nanosheets also displayed antibiofilm properties and were found to be compatible with mammalian cells even at high concentrations.

ACS Applied Bio Materials

We report the fabrication of a plasmonic magneto-luminescent multifunctional nanocarrier (PML-MF ... more We report the fabrication of a plasmonic magneto-luminescent multifunctional nanocarrier (PML-MF nanocarrier) by lysozyme-mediated agglomeration of gold-coated iron oxide nanoparticles (IO@AuNPs) and subsequent coating of these agglomerates with BSA-stabilized gold nanoclusters (BSA-AuNCs). The agglomeration-mediated enhancement of plasmonic absorbance at the NIR biological window helped in plasmonic photothermal therapy (PPTT) by PML-MF nanocarriers. PML-MF nanocarriers demonstrated excellent in vitro bioimaging and magnetic targeting capabilities due to the strong photoluminance and superparamagnetism of the constituent AuNCs and IO@AuNPs, respectively. Moreover, these nanocarriers showed the successful loading and delivery of doxorubicin to cancer cells with a significant killing efficiency that could be synergistically improved by combining with PPTT.

Colloids and Surfaces B: Biointerfaces, 2017

The objective of this work was to develop a simple surface modification technique using keratin d... more The objective of this work was to develop a simple surface modification technique using keratin derived from human hair for efficient cardiomyogenic lineage commitment of human mesenchymal stem cells (hMSCs). Keratin was extracted from discarded human hair containing both the acidic and basic components along with the heterodimers. The extracted keratin was adsorbed to conventional tissue culture polystyrene surfaces at different concentration. Keratin solution of 500μg/ml yielded a well coated layer of 12±1nm thickness with minimal agglomeration. The keratin coated surfaces promoted cell attachment and proliferation. Large increases in the mRNA expression of known cardiomyocyte genes such as cardiac actinin, cardiac troponin and β-myosin heavy chain were observed. Immunostaining revealed increased expression of sarcomeric α-actinin and tropomyosin whereas Western blots confirmed higher expression of tropomyosin and myocyte enhancer factor 2C in cells on the keratin coated surface than on the non-coated surface. Keratin promoted DNA demethylation of the Atp2a2 and Nkx2.5 genes thereby elucidating the importance of epigenetic changes as a possible molecular mechanism underlying the increased differentiation. A global gene expression analysis revealed a significant alteration in the expression of genes involved in pathways associated in cardiomyogenic commitment including cytokine and chemokine signaling, cell-cell and cell-matrix interactions, Wnt signaling, MAPK signaling, TGF-β signaling and FGF signaling pathways among others. Thus, adsorption of keratin offers a facile and affordable yet potent route for inducing cardiomyogenic lineage commitment of stem cells with important implications in developing xeno-free strategies in cardiovascular regenerative medicine.

ACS Applied Nano Materials

Herein, a green method for the development of a novel biodegradable silver nanoparticles (NPs) im... more Herein, a green method for the development of a novel biodegradable silver nanoparticles (NPs) impregnated alginate–chitosan-blended nanocarrier (Ag NPs–Alg–Chi NC) is reported. The synthesis of Ag NPs–Alg–Chi NC is based on the polyelectrolyte complex formation between alginate and chitosan. The composite NC is characterized by ultraviolet–visible spectroscopy, transmission electron microscopy, scanning electron microscopy (SEM), Fourier transform infrared spectroscopy, and X-ray diffraction. The Ag NPs in the NC are found to elicit anticell proliferative effect on refractory U87MG (human glioblastoma) cells at IC 50 of 2.4 μ g mL − 1 for Ag NPs. The cell cycle analysis shows extensive DNA damage. Elevation in reactive oxygen species level indicates induction of oxidative stress in treated cells. Mitochondrial dysfunction in cell death is evident from the depolarization of mitochondrial membrane potential (Δ Ψ m). Fluorescence and SEM images of the treated cells reveal nuclear and morphological changes characteristic of apoptosis, which is further confi rmed by TUNEL assay. The induction of apoptosis at low concentration of Ag NPs present in Ag NPs–Alg–Chi NC in comparison with free Ag

A new and simple ecofriendly method for the synthesis of silver nanoparticles (Ag NPs) using a na... more A new and simple ecofriendly method for the synthesis of silver nanoparticles (Ag NPs) using a natural biopolymer, sodium alginate as both reducing and stabilizing agent is reported. The synthesized NPs were characterized using UV-Vis spectroscopy, transmission electron microscopy (TEM) and selected area electron diffraction pattern (SAED). The alginate capped NPs (Alg–Ag NPs) were found to be antibacterial. The Alg–Ag NPs were blended with varying amounts of chitosan to form polyelectrolyte complex that was cast into stable films. The films were characterized by field emission scanning electron microscopy (FESEM), optical microscopy, Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). The water uptake and mechanical properties of the films were also studied. The blended film demonstrated excellent antibacterial activity against both Gram negative and Gram positive bacteria with more activity against Gram positive bacteria. Thus, the developed films have a potential to be used for various antibacterial applications in biotechnology and biomedical fields.

Water dispersible zinc sulfide quantum dots (ZnS QDs) with an average diameter of 2.9 nm were syn... more Water dispersible zinc sulfide quantum dots (ZnS QDs) with an average diameter of 2.9 nm were synthesized in an environment friendly method using chitosan as stabilizing agent. These nanocrystals displayed characteristic absorption and emission spectra having an absorbance edge at 300 nm and emission maxima (λ emission) at 427 nm. Citrate-capped silver nanoparticles (Ag NPs) of ca. 37-nm diameter were prepared by modified Turkevich process.

Owing to the ever-increasing applications, glittered with astonishing success of gold nanoparticl... more Owing to the ever-increasing applications, glittered with astonishing success of gold nanoparticles (Au NPs) in biomedical research as diagnostic and therapeutic agents, the study of Au NP–protein interaction seems critical for maximizing their theranostic efficiency, and thus demands comprehensive understanding. The mutual interaction of Au NPs and proteins at physiological conditions may result in the aggregation of protein, which can ultimately lead to the formation of Au NP–protein agglomerates. In the present article, we try to appreciate the plausible steps involved in the Au NP-induced aggregation of proteins and also the importance of the proteins' three-dimensional structures in the process. The Au NP–protein agglomerates can potentially be exploited for efficient loading and subsequent release of various therapeutically important molecules, including anticancer drugs, with the unique opportunity of incorporating hydrophilic as well as hydrophobic drugs in the same nanocarrier system. Moreover, the Au NP–protein agglomerates can act as 'self-diagnostic' systems, allowing investigation of the confor-mational state of the associated protein(s) as well as the protein–protein or protein–Au NP interaction within the agglomerates. Furthermore, the potential of these Au NP–protein agglomerates as a novel platform for multifunctional theranostic application along with exciting future-possibilities is highlighted here.