Protein coupled thionine acetate probed silica nanoparticles: An integrated laser-assisted therapeutic approach for treating cancer.

Herein, we report a multifaceted nanoformulation, developed by binding thionine acetate (TA) in silica matrix to form TA loaded silica nanoparticles (STA Nps), which were characterized using various physicochemical techniques. STA NPs were spherical shaped having size 40-50 nm and exhibited good heating efficiency, improved photostability and singlet oxygen production rate than TA alone. In PDT experiment, the rate of degradation for ABDMA was enhanced from 0.1367 min-1 for TA alone to 0.1774 min-1 for STA Nps, depicting an increase in the reactive oxygen species (ROS) generation ability of STA Nps. Further, the cytotoxicity of STA Nps was investigated by carrying out the biophysical studies with Calf thymus DNA (Ct-DNA) and Human Serum Albumin (HSA). The results indicated that the binding of STA Nps to Ct-DNA causes alterations in the double helix structure of DNA and as a result, STA Nps can impart chemotherapeutic effects via targeting DNA. STA Nps showed good binding affinity with HSA without compromising the structure of HSA, which is important for STA Nps sustainable biodistribution and pharmacokinetics. Based on this study, it is suggested that because of the synergistic effect of chemo and phototherapy, STA Nps can be extensively utilized as potential candidates for treating cancer.

Prospecting the cancer therapeutic edge of chitosan-based gold nanoparticles through conformation selective binding to the parallel G-quadruplex formed by short telomeric DNA sequence: A multi-spectroscopic approach.

The biological relevance of G4 structures formed in telomere & oncogenes promoters make them extremely crucial therapeutic target for cancer treatment. Herein, we have synthesized chitosan-based gold nanoparticles (CH-Au NPs) through green method and have investigated their interaction with G4 structures formed by short telomeric sequences to evaluate their potential for targeting G4 structures. Firstly, we have characterized morphological/physical attributes of synthesized CH-Au NPs and salt dependent structural aspects of model G-rich DNA sequence, 12-mer d(T2G4)2 [TETRA] using spectroscopic and biophysical techniques. The molecular interactions between CH-Au NPs and parallel/antiparallel TETRA G4 structures were evaluated using UV-Visible, CD, Fluorescence, CD melting, DLS and Zeta potential studies. The experimental data indicated that CH-Au NPs showed strong binding interactions with Parallel TETRA G4 and provided thermal stabilization to the structure, whereas their interactions with Antiparallel TETRA G4 DNA and Ct-DNA (DNA duplex) were found to be negligible. Further, CH-Au NPs were also investigated for their selectivity aptitude for different G4 structures formed by human telomeric sequences; d(T2AG3)3 [HUM-12] and d(T2AG3)4T [HUM-25]. Our findings suggested that CH-Au NPs exhibited topology specific binding aptitude towards G4 structure, which can be utilized to inhibit/modulate crucial biological functions for potential anticancer activity.

Protein kinases: Role of their dysregulation in carcinogenesis, identification and inhibition.

Protein kinases belong to the phosphor-transferases superfamily of enzymes, which "activate" enzymes via phosphorylation. The kinome of an organism is the total set of genes in the genome, which encode for all the protein kinases. Certain mutations in the kinome have been linked to dysregulation of protein kinases, which in turn can lead to several diseases and disorders including cancer. In this review, we have briefly discussed the role of protein kinases in various biochemical processes by categorizing cancer associated phenotypes and giving their protein kinase examples. Various techniques have also been discussed, which are being used to analyze the structure of protein kinases, and associate their roles in the oncogenesis. We have also discussed protein kinase inhibitors and United States Federal Drug Administration (USFDA) approved drugs, which target protein kinases and can serve as a counter to protein kinase dysregulation and mitigate the effects of oncogenesis. Overall, this review briefs about the importance of protein kinases, their roles in oncogenesis on dysregulation and how their inhibition via various drugs can be used to mitigate their effects.

Nanomaterials and DNA multistranded structures: a treasure hunt for targeting specific biomedical applications.

The advent in nanoscience and nanotechnology has enabled the successful synthesis and characterization of different nanomaterials with unique electrical, optical, magnetic and catalytic activities. However, with respect to sensing applications, nanomaterials intrinsically lack target recognition ability to selectively bind with the analyte. DNA, an important genetic material carrying biopolymer is polymorphic in nature and shows structural polymorphism, forming secondary/multistranded structures like hairpin, cruciform, pseudoknot, duplex, triplex, G-quadruplex and i-motif. Studies reported so far have suggested that these polymorphic structures have been targeted specifically for the treatment or diagnosis of various diseases. DNA is widely used in conjugation with nanomaterials for the development of nanoarchitectures due to its rigidity, sequence programmability and specific molecular recognition, which makes this biomolecule a treasure for designing of DNA based frameworks. These two entities (DNA and nanomaterials) can be used in association with each other, as their alliance can result into creation of novel assay platforms for different purposes, ranging from imaging, sensing and diagnostics to targeted delivery. In this review, we have discussed about the recent reports on association of various mutistranded/ polymorphic forms of DNA with nanomaterials. Furthermore, different applications using this versatile DNA-nanomaterial assembly has also been elaborated at length. This review aims to target the interests of scientists from various interdisciplinary fields, including biologists, chemists and nanotechnologists, who wish to gain an understanding of nano-fabrications using a plethora of DNA polymorphic forms.Communicated by Ramaswamy H. Sarma.

Interface of G-quadruplex with both stabilizing and destabilizing ligands for targeting various diseases.

Guanine-rich DNA sequences may fold back into non-canonical four-stranded secondary structures termed as G-quadruplexes. The role of G-quadruplexes has already been well established in different diseases like cancer, neurological and viral disorders etc. Also, several small molecules have been reported, which can influence the involvement of G-quadruplexes either through stabilization or destabilization in the cellular environment. Growing statistics have associated G-quadruplex assemblies to a discrete biological process in vivo, including DNA replication, transcription, genomic stability, and epigenetic regulation. DNA G-quadruplex existence in human telomere is well recognized attractive target for anticancer drugs. G-quadruplex-interactive ligands have been known to prevent telomerase access as well as telomere capping. To the best of our understanding, the role of G-quadruplexes in virology, neuropharmacology, cancer progression and its treatment has not been discussed on a single platform till date. This review aims to enhance our knowledge regarding these magical sticky quadruplex structures, which have been quite significantly proved to be the part of many cellular processes along with their established in vivo existence. Understanding regarding stabilizing or destabilizing ligands of these multistranded guanine quadruplex structures might be proved as the facilitator of drug discovery process for many incurable diseases in future.

Exploring the interaction of guanidine ligands Amiloride, Rimeporide and Cariporide with DNA for understanding their role as inhibitors of Na+/H+ exchangers (NHEs): A spectroscopic and molecular docking investigation.

The inhibition of Na+/H+ Exchangers (NHEs) has shown efficacy in the pathology of several diseases like tumors, cardiovascular, and neurological disorders. The role of guanidine ligands such as amiloride, cariporide, and rimeporide as NHE inhibitors is very well documented but their interaction studies with genomic DNA are still unexplored. In this study, a combination of various biophysical and molecular docking studies was employed to investigate their binding aspects.UV-Visible, fluorescence, and circular dichroism (CD) studies indicated that guanidine ligands bind to the grooves of Calf Thymus DNA (ctDNA). Fluorescence titration studies depict that amiloride binds to ctDNA with a binding constant in the order of 102 M-1 and free energy change (ΔG0) of -14.05 KJ mol-1. Competitive fluorescence studies indicated the minor groove binding property of amiloride, whereas major groove binding mode was deduced for rimeporide and cariporide. Molecular docking studies were also found to be in accordance with the experimental results, revealing the information about the binding energy of the guanidine ligand-ctDNA complex. The docked structures depicted binding energy of -6.4 kcal mol-1 for amiloride and - 6.6 kcal mol-1 for rimeporide and cariporide. Such physicochemical studies of DNA-ligand interactions may facilitate the understanding of the mechanisms of NHE inhibition.

Nanopaper Biosensors at Point of Care.

In this review, we provide an overview of the nanopaper biosensors used for point of care (POC) diagnostics in various fields such as biomedical, environmental, food safety, and agriculture. The lateral flow assays (LFAs) comprising nanoparticles have drawn the interest of researchers due to their high sensitivity, low cost, lower time consumption, lack of equipment, and easy handling characteristics. These assays have become an integral part of the health sector all over the world over a short time period and are extensively being engaged in diagnosis of viral infections in regions low on resources. A large number of innovative approaches have been introduced in making these test-strips or nanopaper biosensors as quickly as possible, because of their ease of operation, cheaper cost, and quick results, even with the simplest setups or in pathological laboratories, etc. Keeping all this in mind, we have reviewed the nanoparticles based lateral flow test strips (LFTS), their composition, working methods, reaction mechanisms, detection methods, and applications in different fields. We also provide an overview of paper-based microfluidic analytical devices (µPADs) and our perspective about the future trends which may facilitate understanding their applications.

Probing multifunctional azure B conjugated gold nanoparticles with serum protein binding properties for trimodal photothermal, photodynamic, and chemo therapy: Biophysical and photophysical investigations.

Multimodal or combination therapy has been considered as a powerful approach for treatment of complex diseases like cancer. The fascinating physicochemical and optoelectronic properties of gold nanoparticles make them potential candidate for cancer therapeutic and diagnostic applications. Herein, we design a multifunctional nanosystem by conjugating a photosensitizer, Azure B (AB) with citrate reduced gold nanoparticles (CI-Au NPs) through non-covalent interactions. The conjugation of AB with CI-Au NPs was confirmed through UV-Visible absorption spectroscopy and Fourier Transform Infra-red (FT-IR) spectroscopy. The morphology, size, and charge of the prepared nano-conjugates (AB@CI-Au NPs) were determined by transmission electron microscopy (TEM), Dynamic light scattering (DLS), and zeta potential measurements. The proficiency of AB@CI-Au NPs for cancer photo-therapies was demonstrated by evaluating their potential for photothermal heating and singlet oxygen generation in solution upon Visible laser (635 nm, 500 mW/cm2) irradiation. The AB@CI-Au NPs display superior heating efficiency than CI-Au NPs alone or free AB, and offer better photostability as well as singlet oxygen generation rate compared to free photosensitizer. The interaction of AB@CI-Au NPs with Calf thymus DNA (Ct-DNA) and transport protein Bovine Serum Albumin (BSA) were studied using various biophysical techniques including Circular dichroism, UV-Visible and fluorescence spectroscopic studies. AB@CI-Au NPs show intercalative binding with Ct-DNA by inducing local perturbations in double helical structure and hence can exert chemotherapeutic action by targeting DNA. AB@CI-Au NPs also display moderate binding with BSA without any adverse effect on BSA structure, which is desirable for significant biodistribution and pharmacokinetics of AB@CI-Au NPs. Also, in vitro cytotoxicity of the AB@CI-Au NPs with and without laser irradiation (635 nm, 500 mW/cm2) was demonstrated using the hepatocellular carcinoma (HepG2) cell lines. Our findings through photophysical and biophysical studies strongly recommend the exploitation of AB@CI-Au NPs nanoconjugates as a multifunctional probe for trimodal anticancer therapy.

Structural switching/polymorphism by sequential base substitution at quasi-palindromic SNP site (G → A) in LCR of human ß-globin gene cluster.

The human ß-globin gene Locus Control Region (LCR), a dominant regulator of globin gene expression contains five tissue-specific DNase I-hypersensitive sites (HSs). A single nucleotide polymorphism (SNP) (A â†’ G) present in HS4 region of locus control region (LCR), have shown a notable association between the G allele and the occurrence of ß-thalassemia. This SNP site exhibiting a hairpin - duplex equilibrium manifested in A â†’ B like DNA transition has previously been reported from this laboratory. Since, DNA is a dynamic and adaptable molecule, so any change of a single base within a primary DNA sequence can produce major biological consequences commonly manifested in genetic disorders such as sickle cell anemia and ß-thalassemia. Herein, the differential behavior of sequential single base substitutions G â†’ A on the quasi-palindromic sequence (d-TGGGGGCCCCA; HPG11) has been explored. A combination of native gel electrophoresis, circular dichroism (CD), and UV-thermal denaturation (Tm) techniques have been used to investigate the structural polymorphism associated with various variants of HPG11 i.e. HPG11A2 to HPG11A5. The CD spectra confirmed that all the HPG11 variants exhibit a hairpin - duplex equilibrium. Oligomer concentration dependence on CD spectra has been correlated with A â†’ B DNA conformational transition. However, as revealed in gel electrophoresis, HPG11A2 â†’ A5 exhibit the formation of a tetramolecular structure (four-way junction) at higher oligomer concentration. UV-melting studies also supported the melting of hairpin, duplex and four-way junction structure. This polymorphism pattern may possibly be significant for DNA-protein recognition, in the process of regulation of LCR in the ß-globin gene.

Influence of Green Synthesized Zinc Oxide Nanoparticles on Molecular Interaction and Comparative Binding of Azure Dye with Chymotrypsin: Novel Nano-Conjugate for Cancer Phototherapy.

Till date, different types of conventional drugs have been used to fight tumors. However, they have significant flaws, including their usage being constrained because of their low bioavailability, poor supply, and serious side effects. The modern combination therapy has been viewed as a potent strategy for treating serious illnesses, including cancer-type feared diseases. The nanoparticles are a promising choice for cancer therapeutic and diagnostic applications because of their fascinating optoelectronic and physicochemical features. Among the metallic nanoparticles, Zinc oxide nanoparticles possess interesting physicochemical and anti-cancer characteristics, such as ROS generation, high retention, enhanced permeability etc., making them attractive candidates for the treatment and diagnosis of cancer. Zinc oxide nanoparticles showed anti-cancer property via excessive reactive oxygen species (ROS) production, and by the destruction of mitochondrial membrane. Here, we have synthesized organic/inorganic hybrid nanosystem composed of chymotrypsin protein (Chymo) with AzureC (AzC) conjugated with Zinc oxide nanoparticles (ZnONPs). The conjugation of AzureC with ZnONPs was confirmed by transmission electron microscopy (TEM), zeta potential, and dynamic light scattering (DLS) experiment. The interaction of Chymo with AzC alone and AzC-ZnONPs was investigated, and it was observed that the interaction was enhanced in the presence of ZnONPs, which was concluded by the results obtained from different spectroscopic techniques such as UV-Visible spectroscopy, fluorescence spectroscopy and circular dichroism in combination with molecular docking. UV-Visible spectroscopic studies and the corresponding binding parameters showed that the binding of AzC-ZnONPs complex with Chymo is much higher than that of AzC alone. Moreover, the fluorescence measurement showed enhancement in static quenching during titration of Chymo with AzC-ZnONPs as compared to dye alone. In addition to this, circular dichroism results show that the dye and dye-NPs conjugate do not cause much structural change in α-Chymo. The molecular docking and thermodynamic studies showed the predominance of hydrogen bonding, Van der Waal force, and hydrophobic forces during the interactions. After correlation of all the data, interaction of Chymo with AzC-ZnONPs complex showed strong interaction as compared to dye alone. The moderate binding with chymo without any alteration in the structure makes it desirable for the distribution and pharmacokinetics. In addition, the in vitro cytotoxicity of the AzC-ZnONPs was demonstrated on A-549 adenocarcinoma cell line. Our findings from physiochemical investigations suggested that the chymotrypsin coated AzC conjugated ZnONPs could be used as the novel nanoconjugates for various cancer phototherapies.

Nanomaterials to address the genesis of antibiotic resistance in Escherichia coli.

Escherichia is a genus of prokaryotic gram-negative bacteria which forms a vital component of the gut microbiota of homeotherms including humans. Many members of this genus are commensals and pathogenic strains, which are responsible for some of the most common bacterial infections and can be fatal, particularly in the case of newborns and children. The fecal matter in wastewater treatment plants serves as major environmental sinks for the accumulation of Escherichia. The rise in antibiotic pollution and the lateral gene exchange of antibiotic-resistant genes have created antibiotic-resistant Escherichia strains that are often called superbugs. Antibiotic resistance has reached a crisis level that nowadays existing antibiotics are no longer effective. One way of tackling this emerging concern is by using nanomaterials. Punitively, nanomaterials can be used by conjugating with antibodies, biomolecules, and peptides to reduce antibiotic usage, whereas, preventatively, they can be used as either nano-antimicrobial additives or nano-photocatalytic sheets to reduce the microbial population and target the superbugs of environmental Escherichia. In this review, we have explored the threat posed by pathogenic Escherichia strains in the environment, especially in the context of antibiotic-resistant strains. Along with this, we have discussed some nanomaterial-mediated strategies in which the problem can be addressed by using nanomaterials as nanophotocatalytics, antimicrobial additives, drugs, and drug conjugates. This review also presents a brief overview of the ecological threats posed by the overuse of nanomaterials which warrants a balanced and judicious approach to the problem.

Gold nanoclusters: An ultrasmall platform for multifaceted applications.

Gold nanoclusters (Au NCs) with a core size below 2 nm form an exciting class of functional nano-materials with characteristic physical and chemical properties. The properties of Au NCs are more prominent and extremely different from their bulk counterparts. The synthesis of Au NCs is generally assisted by template or ligand, which impart excellent cluster stability and high quantum yield. The tunable and sensitive physicochemical properties of Au NCs open horizons for their advanced applications in various interdisciplinary fields. In this review, we briefly summarize the solution phase synthesis and origin of the characteristic properties of Au NCs. A vast review of recent research work introducing biosensors based on Au NCs has been presented along with their specifications and detection limits. This review also highlights recent progress in the use of Au NCs as bio-imaging probe, enzyme mimic, temperature sensing probe and catalysts. A speculation on present challenges and certain future prospects have also been provided to enlighten the path for advancement of multifaceted applications of Au NCs.

Strategic targeting of non-small-cell lung cancer utilizing genetic material-based delivery platforms of nanotechnology.

Several limitations of conventional cancer treatment such as non-specific targeting, solubility problems, and ineffective entry of chemotherapeutics into cancer cells can be overcome by using nanotechnology targeted drug delivery systems. Some combinations of biomolecules and nanoparticles have proven to be excellent therapeutics for Non-small cell lung cancer (NSCLC) in the last decades. Targeted gene delivery has shown in vivo as well as in vitro promising results with therapeutic efficacy. Gene therapy has shown enhanced transfection efficiency and better targeting potential on several NSCLC cell lines. Still, there are several challenges in nanoparticle-mediated gene therapy, which include stability of biomolecules and nanoparticles during delivery, managing their biodistribution, and reducing the possible cytotoxic effects of the nanoparticles, which need to be solved before clinical trials. Evaluation of therapeutic efficacy of biomolecules and nanoparticle combination in gene therapy must be established to expand the application of nano-gene therapy in cancer treatment.

Innovative application of facile single pot green synthesized CuO and CuO@APTES nanoparticles in nanopriming of Vigna radiata seeds.

Nanopriming is an emerging field of science which uses nanoparticles in solution to improve parameters of seed vigor. This leads to an initial advantage to the crop plant at the germination phase of its life cycle, which is also the most vulnerable phase and may lead to an improved yield. In this study, we have synthesized copper oxide (CuO) and (3-Aminopropyl) triethoxysilane (APTES)-coated CuO (CuO@APTES) nanoparticles via environmentally friendly green synthesis using the extract of Coriandrum sativum (coriander) herb. The synthesized nanoparticles were used as nanoprimers on Vigna radiata (moong bean), a model legume, to promote seed vigor via increase in germination. This was followed by characterization and comparison of both types of nanoparticles using various physicochemical techniques; UV-Visible (UV-Vis), Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), dynamic light scattering (DLS), zeta potential, and transmission electron microscopy (TEM). All characterization techniques pointed out to the successful synthesis and coating of CuO nanoparticles. Seed imbibition and germination assays were performed, which indicated increased imbibition potential and germination promotion at low nanoparticle concentration. Such studies can be used in the development of simple prepackaged nanoprimer products, which can be used by farmers before sowing to provide a boost to their crops and productivity.

Designing a two-stage colorimetric sensing strategy based on citrate reduced gold nanoparticles: Sequential detection of Sanguinarine (anticancer drug) and visual sensing of DNA.

Distance dependent optical properties of colloidal gold nanoparticles offer designing of colorimetric sensing modalities for detection of a variety of analytes. Herein, we report a simple and facile colorimetric detection assay for an anti-cancer drug, Sanguinarine (SNG) and Calf Thymus DNA (Ct-DNA) based on citrate reduced gold nanoparticles (CI-Au NPs). The electrostatic interaction between SNG and CI-Au NPs induce aggregation of Au NPs accompanied with visible colour change of colloidal solution. The assay conditions like salt concentration, pH and reaction time had been adjusted to achieve highly sensitive and fast colorimetric response. Furthermore, the optimized CI-Au NPs/SNG sensing system is used for the detection of Ct-DNA based on the mechanism of anti-aggregation of CI-Au NPs. The simultaneous presence of SNG and Ct-DNA prevent aggregation of Au NPs owing to preferential formation of Ct-DNA-SNG intercalation complex and colour of the Au NPs solution tends to remain red, depending on the concentration of Ct-DNA in solution. The degree of aggregation and anti-aggregation of CI-Au NPs was monitored using Transmission electron microscopic (TEM) measurements and UV-Visible spectrophotometry by analysing the ratio of absorptions for aggregated and dispersed Au NPs. The intercalation mode of binding between SNG and Ct-DNA in CI-Au NPs/SNG sensing system was determined by Fluorescence spectral studies and UV-thermal melting studies. The absorption ratio (A627/A525) of Au NPs exhibited a linear correlation with SNG concentrations in the range from 0 to 0.9 µM with detection limit as 0.046 µM. This optical method can determine Ct-DNA as low as 0.36 µM and the calibration is linear for concentration range 0 to 5 µM. The proposed sensing strategy enables detection as well as quantification of SNG & Ct-DNA in real samples with satisfactory results and finds application in drug or DNA monitoring.

Interaction of a photosensitizer methylene blue with various structural forms (cruciform, bulge duplex and hairpin) of designed DNA sequences.

Functionally important, local structural transitions in DNA generate various alternative conformations. Cruciform is one of such alternative DNA structures, usually targeted in genomes by various proteins. Symmetry elements in sequence as inverted repeats are the key factor for cruciform formation, facilitated by the presence of the AT-rich regions. Here, we used biophysical and biochemical techniques such as Gel electrophoresis, Circular dichroism (CD), and UV-thermal melting analysis to explore the structural status of the designed DNA sequences, which had potential to form cruciform structures under physiological conditions. The gel electrophoresis analysis revealed that the designed 53-mer DNA oligonucleotide sequence CR forms an intermolecular bulge duplex with flanking ends, while another sequence CRC adopts an intramolecular hairpin structure with flanking ends. Their equimolar complex (CRCRC) bestowed much-retarded migration due to the formation of a quite intriguing cruciform structure. CD studies confirmed that all the alternative structures (cruciform, bulge duplex, and hairpin with flanking ends) exhibit characteristics of B-DNA type conformation. A triphasic UV-thermal melting curve displayed by the complex formed by the equimolar ratio (CRCRC) is also suggestive of the formation of the cruciform structure. The interaction studies of CR, CRC, and their equimolar complex (1:1) with a photosensitizer methylene blue (MB) indicated that MB could not stabilize the discrete structures formed by CR and CRC sequences, however, the cruciform structure showed a quite significant increment in the melting temperature. Such studies facilitate our understanding of various secondary structures possibly present inside the cell and their interactions with drug/dye molecules.

Hydrothermal synthesis and characterization of magnetic Fe3O4 and APTS coated Fe3O4 nanoparticles: physicochemical investigations of interaction with DNA.

Magnetic nanoparticles (MNPs) especially iron oxide (Fe3O4) NPs have quite extensively been used for in vivo delivery of biomolecules and drugs because of their high bioconjugation efficiency. In this study, Fe3O4 NPs and (3-Aminopropyl) triethoxysilane (APTS) coated Fe3O4 NPs were synthesized and their interaction with Calf thymus (Ct) DNA has been studied in order to understand their usage in biomedical applications. Hydrothermal method was used for the NPs synthesis. Characterization of NPs was done using techniques like UV-Visible spectroscopy, FTIR spectroscopy, FE-SEM, EDAX, Zeta Sizer and powder XRD. Further, interaction studies of NPs with Ct-DNA were investigated using various physicochemical techniques. In UV-Visible studies, hypochromicity with binding constant 3.2 × 105 M-1 was observed. Binding constants calculated using fluorescence studies were found to be k = 3.2 × 104 M-1, 2.9 × 104 M-1 at 293 and 323 K respectively. Results of UV-Visible and fluorescence studies were in correlation with other techniques like UV-TM and CD. All studies suggested alteration in DNA conformation on interaction with surface engineered Fe3O4 NPs, stabilizing DNA-NPs conjugate via partial intercalation and electrostatic interactions. This study may facilitate our understanding regarding the physicochemical properties and DNA-binding ability of APTS-Fe3O4 NPs for their further application in magnetosensitive biosensing and drug delivery. Iron oxide based magnetic nanoparticles are well known for their excellent bio-conjugation efficiency and therefore APTS-Fe3O4 NPs were synthesized via very simple and benign hydrothermal method. Further, the interaction of APTS-Fe3O4 NPs with calf thymus DNA was studied using various physicochemical techniques to explore their potential in biomedical applications.

Green synthesis and physiochemical characterization of nickel oxide nanoparticles: Interaction studies with Calf thymus DNA.

One of the most promising applications of nanomaterials is that of nanobiosensors, using biomolecules such as nucleic acids as receptors. This study aimed to synthesize nickel oxide nanoparticles (NiO NPs) by an environmentally friendly green synthesis, using the extract of the herb Coriandrum sativum (coriander). The synthesized NPs were characterized using UV-Visible spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction, X-ray photon spectroscopy, field emission scanning electron microscopy coupled with energy dispersive spectroscopy, dynamic light scattering, zeta potential and transmission electron microscopy. All results confirmed the synthesis of pure, spherical, positively charged NiO NPs of around 95 nm in diameter with prominent hydroxyl groups attached to the surface. Furthermore, interaction studies of synthesized NiO NPs with calf thymus DNA (CT DNA) were performed using UV-Visible spectroscopy, UV-thermal melting, circular dichroism, and fluorescence spectroscopy. CT DNA served as a substitute for nucleic acid biosensors. All experimental studies indicated that the NiO NPs bound electrostatically with CT DNA. These studies may facilitate exploring the potential of NiO NP-nucleic acid conjugated materials to be used as nanobiosensors for various applications, especially in pharmacological, epidemiological, and environmental diagnostic applications, and in detection.

Exploring the potential of environment friendly silver nanoparticles for DNA interaction: Physicochemical approach.

Nanosilver, being the most prominent nanoproduct has diverse bio-medical applications and hence the effects associated with their exposure need to be investigated in detail. The interaction of metal nanoparticles with DNA has become a matter of interest, as their effect on structural integrity, synthesis and replication could be explored through it. Present work aims at the facile synthesis and characterization of spherical silver nanoparticles (AgNPs) using Epipremnum aureum leaves extract. Nanoparticles were characterized using UV-Visible spectroscopy, Transmission Electron Microscopy (TEM), High Resolution X-ray Diffraction (HR-XRD) and Dynamic Light Scattering (DLS) studies. The interaction of AgNPs with Calf thymus DNA (CT-DNA) was investigated using different spectroscopic techniques like UV-Visible spectroscopy, UV-thermal melting, Circular Dichroism and fluorescence spectroscopic studies. Fluorescence results suggest van der Waals and H-bonding interactions, which are predominantly responsible for the interaction of AgNPs with CT-DNA. Circular dichroism and thermal melting studies are pointing towards the groove binding of AgNPs to CT-DNA. DNA duplex destabilization was confirmed by the decreased thermal melting temperature of CT-DNA on addition of AgNPs. Present study might open up new vistas for the study of unusual kind of DNA binders, which can destabilize DNA and may further be used for various biomedical applications.

Emerging Trends in Advanced Nanomaterials Based Electrochemical Genosensors.

Advanced nanomaterials indubitably represent one of the most propitious class of new materials due to their intriguing optical, electronic and redox properties. The incredible progress achieved in this research area has been propelled by the development of novel synthetic procedures owing to the emergence of nanotechnology and by the wide range of applications. These nanostructured materials possess high surface area, biocompatibility, nontoxicity and charge-sensitive conductance which have led to the development of simple, rapid, highly sensitive, inexpensive and portable electrochemical genosensors. This review accentuates on the development and validation of various advanced nanomaterials based electrochemical genosensors that utilize unique properties of nanomaterials for signal transduction purpose or as an electroactive species for direct detection of analyte. The intent is to highlight the recent progress on highly sensitive and flexible nanostructured material based electrochemical genosensors that have the potential to be developed as the next generation field-deployable analytical tools.