Mukesh Lavkush Bhaisare

Ceria nanocubic-ultrasonication assisted dispersive liquid–liquid microextraction coupled with matrix assisted laser desorption/ionization mass spectrometry for pathogenic bacteria analysis

A new ceria (CeO2) nanocubic modified surfactant is used as the basis of a novel nano-based microextraction technique for highly sensitive detection of pathogenic bacteria (Pseudomonas aeruginosa and Staphylococcus aureus). The technique uses ultrasound enhanced surfactant-assisted dispersive liquid-liquid microextraction (UESA-DLLME) with and without ceria (CeO2) followed by matrix assisted laser desorption/ionization mass spectrometry (MALDI-MS). In order to achieve high separation efficiency, we investigated the influential parameters, including extraction time of ultrasonication, type and volume of the extraction solvent and surfactant. Among various surfactants, the cationic surfactants can selectively offer better extraction efficiency on bacteria analysis than that of the anionic surfactants due to the negative charges of bacteria cell membranes. Extractions of the bacteria lysate from aqueous samples via UESA-DLLME-MALDI-MS were successfully achieved by using cetyltrimethyl ammonium bromide (CTAB, 10.0 µL, 1.0×10(-3) M) as surfactants in chlorobenzene (10.0 µL) and chloroform (10.0 µL) as the optimal extracting solvent for P. aeruginosa and S. aureus, respectively. Ceria nanocubic was synthesized, and functionalized with CTAB (CeO2@CTAB) and then characterized using transmission electron microscopy (TEM) and optical spectroscopy (UV and FTIR). CeO2@CTAB demonstrates high extraction efficiency, improve peaks ionization, and enhance resolution. The prime reasons for these improvements are due to the large surface area of nanoparticles, and its absorption that coincides with the wavelength of MALDI laser (337 nm, N2 laser). CeO2@CTAB-based microextraction offers lowest detectable concentrations tenfold lower than that of without nanoceria. The present approach has been successfully applied to detect pathogenic bacteria at low concentrations of 10(4)-10(5) cfu/mL (without ceria) and at 10(3)-10(4) cfu/mL (with ceria) from bacteria suspensions. Finally, the current approach was applied for analyzing the pathogenic bacteria in biological samples (blood and serum). Ceria assist surfactant (CeO2@CTAB) liquid-liquid microextraction (LLME) offers better extraction efficiency than that of using the surfactant in LLME alone.

Rapid and direct MALDI-MS identification of pathogenic bacteria from blood using ionic liquid-modified magnetic nanoparticles (Fe3O4@SiO2)

A novel method for pathogenic bacteria identification directly from blood samples using cationic ionic liquid-modified magnetic nanoparticles (CILMS) is reported. The magnetic nanoparticles were prepared by co-precipitation and the core-shell Fe3O4@SiO2 nanoparticles were prepared by the sol-gel process, followed by the grafting of 3-chloropropyltrimethoxysilane that was reacted further with N-methylimidazole to form cationic ionic liquid-modified Fe3O4@SiO2 magnetic nanoparticles (CILMS). The pathogenic bacteria were separated mainly based on the electrostatic interactions among the negative charges of the cell membranes and the positive charges of the CILMS particles. CILMS are used directly without the need for any further apparatus and auxiliary chemicals. The separated cells were detected using matrix assisted laser desorption/ionization mass spectrometry (MALDI-MS). The lowest detectable number of bacteria was 3.4 × 103, 3.2 × 103, and 4.2 × 103 cfu mL-1 for Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus, respectively. The bacterial affinity toward CILMS was investigated using transmission electron microscopy which revealed immobilization of the CILMS on the outer cell membranes. The present approach offers a highly sensitive, fast, and simple method for the cell capture of the pathogenic bacteria. The current approach could be adapted to separate and identify the pathogenic bacteria from septicemic patients or contaminated blood before blood transfusion.

Controlled delivery of dopamine hydrochloride using surface modified carbon dots for neuro diseases.

Delivery of therapeutic agents using water-soluble, highly biocompatible Carbon dots (C-dots) is an efficient strategy to control drug release under physiological milieu. Dopamine hydrochloride (DA), the most important inotropic vasopressor agent used in neurological diseases. In our study DA is anchored to water-soluble carbon dots for controlled release under mimicked in vitro physiological conditions. The tenure of the DA release at pH 7.4 was greatly extended to 60 h for C-dots-DA, in comparison with the control DA alone. The statistical calculation was used to comprehend the release pattern of the DA, which exhibited the pattern of Hixson-Crowell model of release. In order to understand the impact of the C-dots-DA conjugate under physiological conditions, Neuro 2A cells were taken under consideration. The conjugate C-dots-DA was found to be biocompatible against Neuro 2A cells. The survival rate was found to be 74% at maximum concentration of 9 μg mL(-1). In vivo toxicity was studied using thin section of tissues after staining with Hematoxyline and Eosin Yellow (H&E). As per microscopic observations, conjugates did not inflict any anatomical distortions or hostile effects on tissues. Body weight of mice was also taken into consideration after injecting 20 μg mL(-1) of nano-conjugates via tail vein. The impact of nano-conjugate on body weight was found to be negligible after 45 days of observation.

Carbon dots as nanoantennas for anti-inflammatory drug analysis using surface-assisted laser desorption/ionization time-of-flight mass spectrometry in serum

Carbon dots (C-dots)-assisted laser desorption/ionization time-of-flight mass spectrometry (CALDI-TOF MS) is a relatively new approach for the detection of analytes. We have attempted to harness the UV absorption capacity of C-dots (especially at 337 nm) as a matrix for the detection of a widespread use anti-inflammatory drug Mefenamic acid (MFA). Due to the surface modification, excellent water solubility and ultra-small size, C-dots can play an important role in the detection of low molecular weight compounds. In comparison with 2,5-dihydroxy benzoic acid (DHB), C-dots were found to be an outstanding matrix to avoid background signals and fragmentation of the MFA signals. The C-dots are a perfect matrix for the detection of MFA in both positive and negative ion modes from serum with a low detection limit of 0.51 ng and 0.46 ng, respectively.

Tellurium platinate nanowires for photothermal therapy of cancer cells

Among the most celebrated modes of cancer treatment, photothermal therapy has been the most promising tool over the past few years. In spite of the introduction of many novel nanomaterials for photothermal therapy, there is still plenty of room for exploration of naïve materials. We have explored the photothermal properties of metal chalcogenides, namely tellurium platinate nanowires (TePt NWrs), in this work. Upon irradiation with a laser (Ti:sapphire laser, 808 nm) the temperature of the aqueous suspension of TePt NWrs was found to increase to ∼62 °C from room temperature at optimum concentrations. This was due to the stability and high photothermal transduction efficiency of nanorods (NRs) i.e.∼47%. The power to ablate tumor cells was studied using A549 cells and tumor grafted experimental mice models. After an initial exposure for 10 min (808 nm laser at 1 W cm-2), the cells were killed mainly by the process of apoptosis as confirmed by a flow cytometry assisted cell sorting system (FACS; PI-FITC-Annexin V staining). Tumor growth was significantly reduced after photothermal therapy via a combination of TePt NRs and laser, thus proving the importance of this new nanomaterial for cancer photothermal therapy. The current approach has introduced a highly potential photothermal therapy method for applications in the medical world in the near future.

Graphene oxide@gold nanorods for chemo-photothermal treatment and controlled release of doxorubicin in mice Tumor

Graphene oxide (GO) is a close derivative of graphene has unlocked many pivotal steps in drug delivery due to their inherent biocompatibility, excellent drug loading capacity, and shows antibacterial, antifungal properties etc. We used a novel plant material called Gum arabic (GA) to increase the solubility of GO as well as to chemically reduce it in the solution. GA functionalized GO (fGO) exhibited increased absorption in near infra-red region (NIR) which was exploited in photothermal therapy for cancer. In order to understand the shape and size effect of GO which may affect their rheological properties, we have conjugated them with gold nanorods (GNRs) using in situ synthesis of GO@GNRs via seed mediated method. To the above conjugate, Doxorubicin (DOX) was attached at ambient temperature (28±2°C). The release kinetics of DOX with the effect of NIR exposure was also carefully studied via in vitro photothermal killing of A549 cell lines. The enhancement in NIR induced drug release and photothermal property was observed which indicates that the fGO@GNRs-DOX method is an ideal choice for chemotherapy and photothermal therapy simultaneously.

Folic Acid navigated Silver Selenide nanoparticles for photo-thermal ablation of cancer cells

Photothermal ablation of the cancer cells is a non-invasive technique for cancer treatment, involving cellular assassination in presence of photothermal agent. We are reporting silver selenide (Ag2Se) nanoparticles for photothermal therapy using folic acid for selective targeting. The material, when exposed to 808nm laser, the temperature got boosted to 54°C in 6.5min, thus proving its potential for photothermal ablation. The material was highly biocompatible (95%) at highest concentration (10μg/mL) against A 549 cells. However, in presence of laser, the cellular killing was 55%. The mode of death was analyzed using MALDI-TOF MS.

Laser-assisted synthesis of multi-colored protein dots and their biological distribution in experimental mice using a dye tracking method

We report a novel method for the synthesis of ultra-bright green and red colored protein dots (Pr-dots) using continuous and pulse lasers (λ = 534 and 1064 nm) with lysozyme as a precursor in ethanol. The quantum yield of the Pr-dotsRed was calculated to be ∼13% and that of the Pr-dotsGreen was ∼15%. A shift in the fluorescent intensity and the fluorescence color of the Pr-dots under UV light (λem = 365 nm) with respect to changes in the repetition frequency of the laser was observed. After successful synthesis of the Pr-dots, their in vivo bio-kinetics were studied using 5 week old ICR mouse models. The highest accumulation of multi-Pr-dots was observed in the brains of the mice. This method has opened a new door to pursue the application of Pr-dots to ferry drugs across blood–brain barrier (BBB) which is considered very difficult to achieve. Another vital application of the Pr-dots in biological imaging was explored. These multi-colored Pr-dots were used as effective fluorescence probes for the imaging of Vero cells as well as MCF 7 cancer stem cells.

Shape-oriented photodynamic therapy of cuprous oxide (Cu2O) nanocrystals for cancer treatment

We report a novel method used for the synthesis of cuprous oxide nanocrystals at room temperature by varying the concentration of the reducing agent and probed their photodynamic activity on HeLa cells. Three different shapes of cuprous oxide nanocrystals (NCs) were synthesized, including cubic, hexagonal and octahedral forms, and investigated for their photodynamic properties. Cuprous oxide generated reactive oxygen species (ROS) after irradiation with a green laser (λ = 532 nm). TEM, XRD, EDX, and FTIR were applied to characterize their shape factors and optical properties. Cubic, hexagonal and octahedral shapes of cuprous oxide nanocrystals were used for photodynamic therapy via incubation with HeLa cells and irradiation with a green laser. The octahedral NCs exhibit the highest photodynamic activity for killing HeLa cells, as evaluated using a trypan blue assay, and a high production of reactive oxygen species was observed.

Synthesis and characterization of two-dimensional carbon dots decorated with molybdenum oxide nanoflakes with various phases

The optical and morphological properties of the carbon dots (C-dots) decorated with reduced two-dimensional molybdenum oxide (MoO3−x) nanoflakes were investigated. Two dimensional flakes of MoO3−x were decorated with C-dots (C-dots@MoO3−x) using a probe sonication process at room temperature. In the initial stage of the synthetic process, MoO3 nanoflakes were studied before and after exfoliation. Furthermore, the optical and physical properties were studied and significant changes were found in the fabrication of the nanoflakes with varied sonication time intervals. The C-dots@MoO3−x nanoflakes exhibit fluorescent property with maximum absorbance at longer wavelength (850 nm) in comparison to MoO3−x nanoflakes.