Biology subjects

Bhatia, D. D.

Publications and source records attributed to Bhatia, D. D..

14 recordsLinked to original sources

bioRxiv2023

DNA Tetrahedral Nanocages as a Promising Nanocarrier for Dopamine Delivery in Neurological Disorders

Dopamine is a neurotransmitter in the central nervous system that is essential for many bodily and mental processes, and a lack of it can cause Parkinsons disease. DNA tetrahedral (TD) nanocages are promising in bio-nanotechnology, especially as a nanocarrier. TD is highly programmable, biocompatible, and capable of cell differentiation and proliferation. It also has tissue and blood-brain barrier permeability, making it a powerful tool that could overcome potential barriers in treating neurological disorders. In this study, we used DNA-TD as a carrier for Dopamine to cells and zebrafish embryos. We investigated the mechanism of complexation between TD and dopamine hydrochloride using gel electrophoresis, fluorescence and circular dichroism (CD) spectroscopy, atomic force microscopy (AFM), and molecular dynamic (MD) simulation tools. Further, we demonstrate these Dopamine-loaded DNA tetrahedral nanostructures cellular uptake and differentiation ability in SH-SY5Y neuroblastoma cells. Furthermore, we extended the study to zebrafish embryos as a model organism to examine survival and uptake. The research provides valuable insights into the complexation mechanism and cellular uptake of dopamine-loaded DNA tetrahedral nanostructures, paving the way for further advancements in nanomedicine for Parkinsons disease and other neurological disorders.

bioengineering↗

bioRxiv2023

Growth factor-induced desialylation for the fast control of endocytosis

It is commonly assumed that the glycan makeup of glycoproteins that reach the cell surface is final and static. Here, we challenge this notion by the discovery of a molecular switch that induces acute and reversible changes of glycans on the plasma membrane. We demonstrate that within minutes, the epidermal growth factor triggers the galectin-driven endocytosis of cell surface glycoproteins, such as integrins, that are key regulators of cell adhesion and migration. The onset of this process, mediated by the Na+/H+ antiporter NHE-1 and the neuraminidases Neu1/3, requires the pH-triggered enzymatic removal of sialic acids whose presence otherwise prevents galectin binding. Desialylated glycoproteins are then retrogradely transported to the Golgi apparatus where their glycan makeup is reset, and their function is repurposed to regulate EGF-dependent invasive cell migration. Glycosylation at the cell surface thereby emerges as a dynamic and reversible regulatory post-translational modification that controls a highly adaptable trafficking pathway.

cell biology↗

bioRxiv2023

DNA tetrahedron as a carrier of doxorubicin for metastatic breast cancer treatment

Metastatic breast cancer is a significant clinical challenge calling for novel and efficient therapeutic approaches. DNA tetrahedron, a highly programmable nanocage, offers some promising attributes including biocompatibility, stability, and functionalization making it an attractive candidate for drug delivery. In this study, we have explored the potential of DNA tetrahedron as a carrier of doxorubicin, a DNA and RNA synthesis-inhibiting chemotherapy drug. We have encapsulated doxorubicin in DNA tetrahedron (TD: Dox) and subsequently focused on metastatic breast cancer cells for the effect of the same. We showed that TD: Dox has the potential to inhibit the migration of cancerous cells in the 2D model and inhibit the invasion of tumor cells in the 3D model as well. This system also can be uptaken in in vivo zebrafish model as well. Overall, this study promises the TD: Dox system as an ideal drug delivery model and a viable approach for metastatic breast cancer treatment.

bioengineering↗

bioRxiv2023

Red Fluorescent Carbon Nanoparticles Derived from Spinacia oleracea L.: A Versatile Tool for Bioimaging & Biomedical Applications

Carbon-based fluorescent quantum dots are an emerging class of nanoparticles for targeted bioimaging and biomedical applications. We present a facile microwave-assisted approach for synthesizing carbon nanoparticles with bright red fluorescence using ethanolic extracts of Spinacia oleracea leaves, with a quantum yield of 94.67%. These nanoparticles, called CNPs, ranging from 15-50 nm, demonstrated fluorescence emission in the near-infrared (NIR) region between 650 and 700 nm, independent of excitation wavelength. Upon excitation at a wavelength of 410 nm, they exhibit an emission maxima peak at 672 nm. The significant uptake of CNPs in mammalian cells and zebrafish larvae highlights their potential as bioimaging agents in diverse biomedical applications in vivo. Further, these quantum dots enhance cellular proliferation and migration as observed by wound healing assay in mammalian cells, indicating their possible application in tissue engineering and regenerative medicine. These findings suggest that biosynthesized carbon nanoparticles possess significant potential for biomedical activities, which can serve as a robust benchmark for researchers towards promoting sustainability.

bioengineering↗

bioRxiv2023

Psidium guajava derived carbon nanoparticles: A promising red emissive cellular bioimaging agent

We report a simple, cost-effective, microwave-assisted green synthesis route of red-emitting fluorescence carbon nanoparticles (CNPs) using Psidium guajava (Guava leaves). The synthesis of CNPs is a simple, affordable, and rapid method of producing carbon nanoparticles. The CNPs were characterized by various spectroscopic and microscopic techniques. Atomic force microscopy studies showed that the average size of CNPs is approximately 50 nm. The CNPs exhibited excellent photoluminescence properties with a maximum emission at 677 nm, making them suitable for bioimaging applications. The Ionic, photostability, and thermal stability of CNPs were also checked to understand their robustness. Retinal pigment epithelium (RPE) cells were exposed to these nanoparticles and showed very efficient uptake, some fraction of it also getting targeted to the nucleus, indicating that CNPs are non-toxic and biocompatible for future biological experiments. The results indicate that guava leaves can be a promising source for the synthesis of red emissive CNPs through the very simple method of synthesis and with bioimaging applications.

bioengineering↗

bioRxiv2022

pH - responsive, reversible A-motif based DNA hydrogels: synthesis and biosensing applications

Functional DNA hydrogels using various motifs and functional groups require perfect sequence designing to avoid cross-bonding interference with self or other structural sequences. The present work reports an A-motif functional DNA hydrogel that does not require any sequence design. A-motif DNA is a non-canonical parallel DNA duplex structure comprises homopolymeric deoxyadenosines (poly-dA) strands that undergo conformational changes from single strands at neutral pH to a parallel duplex DNA helix at acidic pH. Despite many advantages over other DNA motifs like no sequence, design is required and no cross-bonding interference with other structural sequences, A-motif has not been explored much. We successfully synthesized DNA hydrogel utilizing A-motif as a reversible handle to polymerize DNA three-way junction (3WJ). The composed A-motif hydrogel was first characterized by EMSA, & DLS, which shows the formation of higher-order structures. Further, we utilized imaging techniques like atomic force microscopy (AFM) and scanning electron microscope (SEM) validating its hydrogel like highly branched morphology. pH-induced conformational transformation from monomers to gel is quick and reversible, and was analysed for multiple acid-base cycles. The sol-to-gel transitions and gelation properties is further examined using rheological studies. The use of A-motif hydrogel in the visual detection of pathogenic target nucleic acid sequence is demonstrated for the first time using the capillary assay. Moreover, the pH-induced hydrogel formation is observed in-situ as a layer over the mammalian cells. The proposed A-motif DNA scaffold has enormous potential in designing stimuli-responsive nanostructures that can be utilized for many biological applications.

bioengineering↗

bioRxiv2022

Dynein functions in galectin-3 mediated processes of clathrin-independent endocytosis

Multiple endocytic processes operate in cells in tandem for the uptake of multiple cargoes, metabolites, and signaling molecules that are involved in diverse cellular functions including cell adhesion and migration. The best studied endocytic process involves the formation of a well-defined cytoplasmic coat at sites of uptake made of clathrin and its interacting partners. Galectin-3 (Gal3), an endogenous lectin, binds to glycosylated membrane receptors and glycosphingolipids (GSLs) to drive membrane bending, leading to the formation of tubular membrane invaginations which undergo scission to form a morphologically distinct class of uptake structures, termed clathrin-independent carriers (CLICs). This mechanism has been termed the GlycoLipid-Lectin (GL-Lect) hypothesis. Which components from cytoskeletal machinery are involved in the scission of CLICs remains yet to be explored. In this study, we propose that dynein, a retrograde motor protein, is recruited onto Gal3-induced tubular endocytic pits and provides the pulling force to for friction driven scission. Uptake of Gal3 and its cargoes (CD98/CD147) is significantly dependent on dynein activity, whereas the uptake of transferrin (a marker for clathrin-mediated endocytosis) is only slightly affected upon dynein inhibition. Dynein inhibition also affects cellular organelle distribution, 3D cell invasion and wound healing. Our study thereby reveals functions of dynein in individual and collective cell migration in 2D and 3D that are tightly coupled to endocytic processes in cells.

cell biology↗

bioRxiv2022

Novel class of yellow emitting carbon dots stimulate collective cell migration and 3D uptake in vivo

We present a new class of nitrogen-doped yellow fluorescent carbon dots, synthesized using a one-step hydrothermal method. These bright fluorescent nanoparticles have excitation and emission spectra near the red region of the visible light spectrum that are quite useful for bioimaging applications. Using organic molecules like ortho- phenylenediamine (OPDA), L-ascorbic acid and urea, yellow fluorescent carbon dots (CDs) were synthesized. We obtained a scalable number of CDs having an average size of 3 nm. The CDs show significant emission spectra in the yellow fluorescence region ({lambda}em= 557 nm). The CDs show remarkable stability in their fluorescence in different pH conditions, ionic stability, photostability as well as thermal stability. These CDs are efficiently uptaken by mammalian cells through clathrin-mediated pathway. Apart from in vitro studies we have also used zebrafish larvae as a 3D in vivo model, and showed that CDs were uptaken efficiently by larvae showing maximum accumulation and fluorescence in the yolk sac region and the notochord region. The CDs also offer enhancement in cell proliferation, hence showing the application in wound healing. The fluorescence of CDs is quite robust and is not affected by most external stimuli, hence can be explored as a promising bioimaging tool for targeted bioimaging and biomedical applications.

bioengineering↗

bioRxiv2022

Green emitting carbon quantum dots (GCQDs) to probe endocytic pathways in cells; for tissue and in vivo bioimaging

Small sized, carbon-based organic nanoparticles have recently gained attention due their advantage of biocompatibility, photostability and biological non-toxicity as compared to their inorganic counterparts. Herein, a new class of small (5-8 nm), green emitting fluorescent carbon quantum dots (GCQDs) were synthesized using organic substrates like citric acid and ascorbic acid in aqueous solvent containing water and ethanol. The very small size and bright green photoluminescence prompted their use for both in vitro and in vivo bioimaging. GCQDs were uptaken via clathrin mediated pathways in mouse kidney and liver primary cells. Similarly, they showed active uptake and distribution in the zebrafish embryo model system. The optical tunability and surface modification properties of these GCQDs provide a platform to be explored for them to emerge as a new class of targeted bioimaging entities, as well as tools for biomedical applications.

bioengineering↗

bioRxiv2022

Hypoxia modulates cellular endocytic pathways and organelles with enhanced cell migration and 3D cell invasion

Hypoxia, a decrease in cellular or tissue level oxygen content, is characteristic of most tumours and shown to drive cancer progression by altering multiple subcellular processes. We hypothesized that the cancer cells in a hypoxic environment might have slower proliferation rates and increased invasion and migration rate with altered endocytosis when compared to the cancer cells in the periphery of the tumour mass that experiences normoxic condition. Using chemically induced hypoxia, a short hypoxic exposure increased the uptake of clathrin independent endocytic marker Galectin-3, but a prolonged hypoxic exposure decreased clathrin-independent endocytic uptake, while clathrin mediated endocytosis remained unaffected. Subcellular organelles such as mitochondria showed enhanced intensity to withstand the hypoxic stress, while other organelles such as ER were significantly decreased. The proliferation rates decreased, and the migration and invasion rate increased in cancer cells in hypoxic condition compared to normoxic cancer cells.These data suggest that hypoxia modulates cellular endocytic pathways with decreased proliferation and enhanced cell migration and invasion. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=126 SRC="FIGDIR/small/480665v1_ufig1.gif" ALT="Figure 1"> View larger version (53K): org.highwire.dtl.DTLVardef@56841corg.highwire.dtl.DTLVardef@1fb82dborg.highwire.dtl.DTLVardef@14c3253org.highwire.dtl.DTLVardef@17c0381_HPS_FORMAT_FIGEXP M_FIG C_FIG

cancer biology↗

bioRxiv2022

Self-assembled DNA nanostructures promote cell migration & differentiation of human umbilical vein endothelial cells

DNA nanostructures have been explored for capabilities to influence cellular behavior and its functions. Recent times have seen the development of new emergent functionalities of DNA nanodevices as class of biomaterials with immense capacity to interface with biological systems and having vast potential in disease diagnosis and therapeutics. Being chemically robust and biocompatible in nature, DNA nanostructures have been surface modified and structurally fine-tuned to find emerging applications in the field of stem cell therapy and tissue regeneration. DNA nanostructures can be utilized for therapeutic angiogenesis that involves induction of blood vessel formation and can be used to treat ischemic diseases like stroke or heart failure. This work addresses the effect of DNA nanostructures structural topology in their capacity to stimulate endothelial cells angiogenesis. We tested a panel of four geometries of DNA nanostructure and checked their potential on the differentiation of human umbilical vein endothelial cells (HUVECs). While different DNA nanostructure geometries showed successful angiogenesis induction and cell migration in HUVECs, tetrahedral DNA cages showed the maximum uptake and angiogenesis potential indicating that not only the composition of materials, but also the 3D arrangement of ligands might also play role in stimulating the angiogenesis process.

bioengineering↗

bioRxiv2021

Ligand geometry dictates cellular and in vivo uptake of 3D DNA nanostructures

Fabrication of nanoscale DNA devices to generate 3D nano-objects with precise control of shape, size, and presentation of ligands has shown tremendous potential for therapeutic applications. The interactions between different topologies of 3D DNA nanostructures and the cell membranes are crucial for designing efficient tools for interfacing DNA devices with biological systems. The practical applications of these DNA nanocages are still limited in cellular and biological systems owing to the limited understanding of interactions of different surface topologies of DNA nanodevices with cell membranes. The correlation between the geometry of DNA nanostructures and their internalization efficiency remains elusive. We investigated the influence of the shape and size of 3D DNA nanostructure on their cellular internalization efficiency. We found that of different geometries designed, one particular geometry, i.e., the tetrahedral shape, is more favoured over other geometries for their cellular uptake in 2D and 3D cell models. This is also replicable for cellular processes like 3D cell invasion assays in 3D spheroid models and passing the epithelial barriers in in-vivo zebrafish model systems. Our work establishes ground rules for the rational designing of DNA nanodevices for their upcoming biological and biomedical applications.

bioengineering↗

bioRxiv2021

DESIGNER DNA HYDROGELS TO STIMULATE 3D CELL INVASION BY ENHANCED RECEPTOR EXPRESSION AND MEMBRANE ENDOCYTOSIS

DNA has emerged as one of the smartest biopolymers to bridge the gap between chemical science and biology to design scaffolds like hydrogels by physical entanglement or chemical bonding with remarkable properties. We present here a completely new application of DNA based hydrogels in terms of their capacity to stimulate membrane endocytosis, leading to enhanced cell spreading and invasion for cells in ex-vivo 3D spheroids models. Multiscale simulation studies along with DLS data showed that the hydrogel formation was enhanced at lower temperature and it converts to liquid with increase in temperature. DNA hydrogels induced cell spreading as observed by increase in cellular area by almost two-folds followed by increase in receptor expression, endocytosis and 3D invasion potential of migrating cells. Our first results lay the foundation for upcoming diverse applications of hydrogels to probe and program various cellular and physiological processes that can have lasting applications in stem cells programming and regenerative therapeutics.

bioengineering↗

bioRxiv2021

Water soluble, red emitting, carbon nanoparticles stimulate 3D cell invasion via clathrin-mediated endocytic uptake

Bright, fluorescent nanoparticles with excitation and emission towards the red end of the spectrum are highly desirable in the field of bioimaging. We present here a new class of organic carbon-based nanoparticles (CNPs) with robust quantum yield and fluorescence towards the red region of the spectrum. Using organic substrates like para-phenylenediamine (PPDA) dispersed in diphenyl ether and reflux conditions, we achieved scalable amounts of CNPs of the average size of 25 nm. These CNPs were readily uptaken by different mammalian cells, and we show that they prefer clathrin-mediated endocytosis for their cellular entry route. Not only can these CNPs be specifically uptaken in cells, but they also stimulate cellular processes like cell invasion from 3D spheroid models. These new class of CNPs, which have sizes similar to proteinaceous ligands, hold immense potential for their surface functionalization, whereby they could be explored as promising bioimaging agents for biomedical imaging and intracellular drug delivery.

bioengineering↗