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Citations since 2017
18 Research Items
In the biological system, the intracellular pH (pHi) plays an important role in regulating diverse physiological activities, including enzymatic action, ion transport, cell proliferation, metabolism, and programmed cell death. The monitoring of pH inside living cells is also crucial for studying cellular events such as phagocytosis, endocytosis, an...
Upconversion nanoparticles (UCNPs) are excited in the near infrared (NIR) biological transparency window, but emits anti-Stokes shifted photons in the visible that are extremely photostable and ideally suited for biomedical imaging. First, we synthesize a UCNP-mOrange fluorescent protein conjugate that forms a Forster resonance energy transfer (FRE...
Composites or hybrid materials offer diverse properties not achievable in pure materials. Here we critically review the interesting and controllable fluorescence and photothermal properties of diverse hybrid materials containing up-conversion nanoparticles (UCNPs). These hybrids couple plasmons, photonic crystals, bio-surfaces, and two dimensional...
Fipronil and its metabolite fipronil sulfone, when found in some food products, such as eggs, have caused major public health concerns. In this study, we used gold nanorods (AuNRs) and graphene oxide (GO) nanocomposites to fabricate a layer-by-layer assembled three dimensional (3D) substrate for toxin detection by surface enhanced Raman scattering...
Graphene oxide (GO) and gold nanorods (AuNRs) have been extensively evaluated for broadband (325-980 nm) photothermal (PT) heat generation and efficiency, on substrates having contrasting thermal conductivities. Infrared thermal imaging of the PT agents under broadband irradiation showed a maximum rise of local temperature of chicken kidney tissue...
We report two nanocomposites (NC) of upconversion nanoparticles (UCNPs): i) with a fluorescent mOrange (mO) fluorescent protein for fluorescence-based intracellular pH sensing, and ii) with molybdenum disulphide (MoS 2) for ultrasensitive broadband (325-1064 nm) photodetection. The UCNP-mOrange fluorescent protein (FP) pH probe uses a Förster Reson...
Fluorescence based intracellular pH nanoprobes have been developed that overcomes the limitations imposed by shallow penetration depth of ultraviolet excitation, photostability, phototoxicity, and interference from background autofluorescence. In this study, we have constructed a Förster Resonance Energy Transfer (FRET) based pH nanoprobe using upc...
Hybrid or composite nanomaterials have emerged that demonstrates superior optoelectronic performance over pure nanomaterials that lacks broadband usage, or responsivity, or both, mainly because of the limitation of the collection of photogenerated carriers. We have addressed this problem by using a composite of MoS2 and a multi-photon absorbing lan...
An "all optical" methodology, including Raman and optical transmission spectroscopy, is presented to study the thermal degradation in edible oils. Oils rich in monounsaturated (MU), polyunsaturated (PU), and saturated (S) fatty acids (FA) were heated above and below their smoke point (∼230 ℃). While the intensity (I) of the identified saturated (C-...
980 nm multiphoton absorbing lanthanide doped up-conversion nanoparticles (UCNPs) are emerging as fluorophores, and photothermal agents, but limited by the low quantum yield of its visible fluorescence. In a way similar to metal enhanced fluorescence, we demonstrate that a monolayer of graphene could quench the 540 nm (green) fluorescence from the...
We demonstrate that the upconversion nanoparticles (UCNPs) fluoresce 50 times more on a gold (Au) coated Cicada wing. UCNPs are attractive bioimaging, and therapeutic materials as it is excited in the infrared, limited only by the low fluorescence quantum yield. Here, a plasmonic effect, coupled with an anti-reflecting (AR) Cicada wing substrate co...
This particular guide is based upon the information available on the web and from my personal experience. Through this guide, one should be able to choose the correct media and reagents for HeLa cells. The protocol for HeLa cells passaging and preparation of other reagents (Appendix) is made available to the readers through this article.
A NIR (980 nm) absorbing phosphor, known as upconversion nanoparticles (UCNPs), is used as a probe to estimate the penetration depth of 980 nm light in Porcine tissue. We have used a Fluorolog spectrophotometer system to record the fluorescence emission intensity of the UCNPs (@540 nm) while exciting with 980 nm laser, that passes through different...
Theranostics involves the concept of diagnostics and therapy within a single platform. A simple definition of theranostics made by Warner1. Generally, in the area of biomedical science, inorganic/organic nanomaterials are being used for decades to target and eradicate the disease, Cancer in particular. The theranostics role of these nanomaterials i...
I am here for specific answers or a list of investigation tools to determine the newly developed drugs/inhibitors/medicines.
Why does the response time of the photodetector change with the chopper frequency of incident illumination?
This question is more based on technical insight of Plagiarism checker software. How could they detect a sentence that has the from another reported article? What are the criteria for sentences/statements are considered plagiarised? and how can plagiarism software know about it?
I am keen to explore, if there's any effect of Donor's Lifetime on its energy transfer ability to acceptor molecule, in FRET.
For example, if we have a donor of lifetime longer (I would say much longer) than the acceptor molecule, will this affect the energy transfer efficiency, making it low/high?
On the hand, if donor-acceptor conventionally have a similar magnitude of lifetime (say YFP/CFP, how high or low will be the energy transfer efficiency.
I am just a beginner in cell culture. I opt HeLa cells as the first.
As of now, I know, to culture any cells, we need media, antibiotics and many other reagents. However, depending on each cell type above mentioned reagent condition changes. For HeLa cells, what is the best reagent conditions is acceptable? I have found tons of document to learn from. Eventually, some are conflicting with each other. For example, some says DMEM (High Glucose, L-Glutamine)+10%FBS is suitable, Some says DMEM (High Glucose+Pyruvate) is suitable, and some says EMEM is suitable.
I would highly highly appreciate all your inputs, comes from your research experience and expertise.
N.B.: I will need HeLa cells for not to perform any core biological study but for Biomedical Imaging purpose.
I intend to start working on HeLa cells and I read online that, the doubling time of HeLa cells is ~20.67 hrs. But, meanwhile, I was told by a colleague of mine that when HeLa cells grows old (not sure if I am using the correct terminology- 'grow old' or old generation), need about 48 hrs to become double of its number. Why is it so?
I would appreciate all your answers.
We fabricated two Photoconductor type MoS2 based Photodetector device. In one we noticed Positive photoresponse and Negative photoresponse on the other. How to define and explain these two phenomena in terms of carrier movement or any other mechanism. Basically I would appreciate if anyone could explain the correct definition of positive and negative photoresponse in photodetector devices.
Recently, I have investigated vibration modes in NaGdF4 nanocrystal, and I came across of some bands in the resulting spectrum , somewhere at ~250, 300, and 360 cm-1. Somehow, I could not able to find any references to quantify and back the analysis. I would be grateful, if anyone insight me with your great knowledge related to this situation.
Thanks in advance and hope to hear from someone soon.
Why the MoS2 single layer has the direct and larger band gap compare to its bulk counterparts, which has smaller but indirect band gap.
Oleic acid ligand on as prepared nanoparticles (dispersed in cyclohexane) has been exchanged by the citric acid ligand with -COOH terminated at its end and could be dispersed in water. I am just curious how these new ligands on the nanoparticles' surface will affect on lifetime (fluorescence), will it let the lifetime decrese or increase?
I want to prepare following two different buffer with different pH stock (20 ml each).
1. Citrate buffer (pH: 3, 4, 5, and 6)
2. Phosphate buffer (pH: 7, 8)
I would be grateful if someone provides me the direct protocol and chemical name to be used in order to prepare these mentioned buffers.
N.B: I am not expert in chemistry, the theory/equations behind the buffer chemistry would be much appreciated.
Thank you in advance.