32 research outputs found
Visible light enhanced selective benzene response of hexagonal atomic structured CuS microcloves
No full textWe have reported CuS microcloves (MCs) for highly selective detection of benzene using scanning kelvin probe (SKP) technique. The electron microscopy investigations revealed the formation of clove shaped CuS with a size of about 1–2 µm at 180 °C and 6 h. The time of reaction significantly affected the crystallinity as well as the morphology of resulting CuS materials. The investigations on adsorption behavior of different types of common volatile organic compounds (VOCs) with varying charge and nature revealed an outstanding selectivity towards benzene when compared to other VOCs. The difference in work function between gold tip and sensor surface modified with CuS MCs was decreased under the exposure of light, most likely caused by transfer of electrons to conduction band of CuS under illumination of light. As a result, the CuS MCs showed enhanced photo response in visible light exposure in the presence of benzene. A chemiresistive type sensor device was fabricated using CuS MCs and exposed to benzene vapor in a concentration ranging from 2.8 to 11.2 ppm. The sensitivity was found to be 1.63 × 10-3 ppm−1. Notably, a rapid response time of ∼6 s and recovery time of ∼ 16 s was achieved for the sensor at a benzene concentration of 5.6 ppm at room temperature. Also, considerable and repeatable sensor response was observed for 560 ppb of benzene vapor at 70 °C. Hence, these results suggested that the CuS MCs have huge potential as novel material for selective benzene detection in gas phase towards breath analysis and other environmental monitoring.Dr. Anandhakumar Sundaramurthy acknowledges the financial support from Science and Engineering Research Board (SERB), Government of India (File Nos. CRG/2020/004175 and SIR/2022/001264). Dr. Yuvaraj Sivalingam acknowledges the financial support from Science and Engineering Research Board (SERB), Department of Science and Technology (DST), Government of India, under ECRA (file no. ECR/2017/001218) and CRG (file no. CRG/2021/006647). The authors specially thank to Rahul S. Ghuge and Balaji Nandhakumar for gas sensor device fabrication and testing. The authors would like to thank SRM Institute of Science and Technology (SRM IST) for providing research facilities. We also acknowledge the Nanotechnology Research Centre (NRC), SRMIST for providing the research facilities
Lysozyme microspheres incorporated with anisotropic gold nanorods for ultrasound activated drug delivery
No full textWe report on the fabrication of lysozyme microspheres (LyMs) incorporated with gold nanorods (NRs) as a distinctive approach for the encapsulation and release of an anticancer drug, 5-Fluorouracil (5-FU). LyMs with an average size of 4.0 ± 1.0 µm were prepared by a sonochemical method and characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Fourier-transform infrared spectroscopy (FTIR). The LyMs were examined using hydrophobic (nile red) as well as hydrophilic (trypan blue) dyes under confocal laser scanning microscopy (CLSM) to obtain information about the preferential distribution of fluorescent molecules. Notably, the fluorescent molecules were accumulated in the inner lining of LyMs as the core was occupied with air. The encapsulation efficiency of 5-FU for LyMs-NR was found to be ∼64%. The drug release from control LyMs as well as LyMs incorporated with NRs was investigated under the influence of ultrasound (US) at 200 kHz. The total release for control LyMs and LyMs incorporated with gold NRs was found to be ∼70 and 95% after 1 h, respectively. The density difference caused by NR incorporation on the shell played a key role in rupturing the LyMs-NR under US irradiation. Furthermore, 5-FU loaded LyMs-NR exhibited excellent anti-cancer activity against the THP-1 cell line (∼90% cell death) when irradiated with US of 200 kHz. The enhanced anti-cancer activity of LyMs-NR was caused by the transfer of released 5-FU molecules from bulk to the interior of the cell via temporary pores formed on the surface of cancer cells, i.e., sonoporation. Thus, LyMs-NR demonstrated here has a high potential for use as carriers in the field of drug delivery, bio-imaging and therapy
Polyelectrolyte capsules preloaded with interconnected alginate matrix: An effective capsule system for encapsulation and release of macromolecules
No full textHydrogen bonded niosomes for encapsulation and release of hydrophilic and hydrophobic anti-diabetic drugs: An efficient system for oral anti-diabetic formulation
No full textPolyelectrolyte Multilayer Film Coated Silver Nanorods: An Effective Carrier System for Externally Activated Drug Delivery
No full textNanozyme controlled photothermal heat generation on nanoceria decorated MoS2 nanoflowers for enhanced cytotoxicity in cancer chemo-photothermal therapy
No full textIn recent years, the fabrication of nanomaterials with built-in ability to mimick biological enzymes (nanozymes) is gaining popularity for biomedical applications, especially for cancer photothermal therapy, based on non-toxic and photo-thermal heat generating 2D materials. The use of 2D inter-layered MoS2 nanoflowers (NFs) is especially interesting as it results in nanozymes that are photostable and biocompatible for normal cells under physiological conditions. In this work, we have synthesized MoS2 nanoflowers (NFs) decorated with CeO2 nanoparticles (NPs) using two linker molecules of cysteine and polyethylenimine connected through carbodiimide chemistry. The electron microscopy investigations revealed the formation of flower shaped MoS2 of 400 ± 100 nm in size decorated with spherical shaped CeO2 NPs of 15±5 nm in size. The fabricated nanozymes were investigated by UV–visible (UV–vis), FTIR spectroscopy, Raman spectroscopy and dynamic light scattering. The NFs decorated with long-chain PEI molecules demonstrated higher photo-thermal heat generation when compared to nanozymes decorated with low molecular weight PEI. Notably, the photo-thermal heat generation, biocompatibility, anti-cancer activity of nanozymes are significantly influenced by molecular weight of PEI, concentration of nanozymes, time duration of near-infrared (NIR) light exposure, power density of NIR light and folic acid (FA) conjugation. The nanozymes conjugated with FA on their surface exhibited excellent anti-cancer activity against human colon cancer cells under NIR light exposure at 808 nm and 0.5 W/cm2. Hence, the nanozymes demonstrated here have huge potential as nanophoto-thermal agents in cancer photothermal therapy.</p
Poly(2-n-propyl-2-oxazoline)/tannic acid nanocapsules with in-situ synthesized gold nanorods for cancer theranostics
No full textThe concept of hollow polymeric capsules fabricated with thermoresponsive polymers has revealed immense possibilities in the field of nanomedicine due to their tunable temperature and pH responsiveness caused by lower critical solution temperature (LCST) behavior. Herein, we report a new methodology to in-situ synthesize gold nanorods (AuNRs) within the pores of mesoporous silica nanoparticles (NPs) by trapping gold seed crystals and growing them into NRs in the presence of a weak reducing agent. The mesoporous silica NPs with incorporated NRs, i.e., modified silica NPs (SiO2-NRs) were used as sacrificial template for the fabrication of hollow polymeric multilayer capsules via layer-by-layer (LbL) assembly using poly(2-n-propyl-2-oxazoline) (PnPrOx) and tannic acid (TA) as layer components. The NRs of 25 +/- 5 nm in size were uniformly distributed in the interior structure of PnPrOx/TA nanocapsules. The photo-thermal conversion efficiency of the PnPrOx/TA nanocapsules was found to be 47.5%. The release of encapsulated doxorubicin was found to be 55%, which increased to 68% when the incubation time was increased from 1 to 2 h. An on-demand burst release of 56% of the drug occurred within 2 min of NIR light exposure, and it reached 72% within 30 min, which inflicted major damage to cancer cells. Notably, the capsule suspension temperature increase from room temperature to 47 degrees C under laser light exposure, which is not only playing a key role in rupturing the capsules to enhance the drug release but also induces a hyperthermia effect in the tumor environment. Further, the in-vitro cytotoxicity experiments with human epithelial HEp-2 cells and fibrosarcoma HT1080 cells revealed an enhanced anti-cancer activity due to a synergistic chemo-photothermal effect. Hence, the proposed nanocapsule system can provide a unique, cheap, and efficient way of fabricating cancer theranostics for in-vivo applications
Graphene oxide/oxidized carbon nanofiber/mineralized hydroxyapatite based hybrid composite for biomedical applications
No full textGraphene nanoplatelets-silver nanorods-polymer based in-situ hybrid electrode for electroanalysis of dopamine and ascorbic acid in biological samples
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