Two photon excitable graphene quantum dots for structured illumination microscopy and imaging application: lysosome specificity and tissue-dependent imaging

Two-photon active Graphene Quantum Dots (GQDs) are obtained from extracts of the neem root. These biocompatible GQDs are found to be suitable for structured illumination microscopy. Two-photon microscopy ensured lysosome specificity of GQDs in live cells and confocal luminescence microscopic studies showed tissue-dependent localization of GQDs in Zebrafis

Imaging cellular trafficking processes in real time using lysosome targeted up-conversion nanoparticles

β-NaYF4:Yb,Gd up-conversion nanoparticles, UCNPs, surface functionalized with suitable targetting peptides function as nontoxic lysosome-specific imaging probes

Nanocarriers used as probes for super-resolution microscopy

Super-resolution microscopy (SRM) has revolutionized the study of cell biology, enabling researchers to visualize cellular structures with nanometric resolution, single-molecule sensitivity, and with multiple colors using conventional fluorophores. SRM is well-suited for volumetric live-cell imaging and helps in extracting quantitative information on spatial distributions. It can be used to estimate the absolute numbers of proteins or other macromolecules or nanostructured material within subcellular compartments, characterize their structures, and their nano/bio interactions. Although a number of recent general reviews on SRM have elaborated its role in chemical and clinical biology, as well as nanomedicine, herein, we provide an overview of the use of luminescent nanocarriers (LNC) in SRM imaging and single-molecule tracking. The role of LNCs in controlling the brightness and stability of emissive states is discussed with a special focus on organelle-specific delivery and how this approach can be utilized to produce novel optical-switched systems. We also discuss the challenges related to the molecular targeting of such material in biological systems. In doing so, we will provide practical guidance for super-resolution imaging in nanomedicine research, its technical challenges, and the opportunities for future advancement

Mitochondria Targeting Non-isocyanate-based Polyurethane Nanocapsules for Enzyme-Triggered Drug Release

Surface engineering of nanocarriers allows fine tuning of their interactions with biological organisms, potentially forming the basis of devices for the monitoring of intracellular events or for intracellular drug delivery. In this context, biodegradable nanocarriers or nanocapsules capable of carrying bioactive molecules or drugs into the mitochondrial matrix could offer new capabilities in treating mitochondrial diseases. Nanocapsules with a polymeric backbone that undergoes programmed rupture in response to a specific chemical or enzymatic stimulus with subsequent release of the bioactive molecule or drug at mitochondria would be particularly attractive for this function. With this goal in mind, we have developed biologically benign nanocapsules using polyurethane-based, polymeric backbone that incorporate repetitive ester functionalities. The resulting nanocapsules are found to be highly stable and monodispersed in size. Importantly, a new non-isocyanate route is adapted for the synthesis of these non-isocyanate polyurethane nanocapsules (NIPU). The embedded ester linkages of these capsules' shells have facilitated complete degradation of the polymeric backbone in response to a stimulus provided by an esterase enzyme. Hydrophilic payloads like rhodamine or doxorubicin can be loaded inside these nanocarriers during their synthesis by an interfacial polymerization reaction. The post-grafting of the nanocapsules with phosphonium ion, a mitochondria-targeting receptor functionality, has helped us achieve the site-specific release of the drug. Co-localization experiments with commercial mitotracker green as well as mitotracker deep red confirmed localization of the cargo in mitochondria. Our in-vitro studies confirm that specific release of doxorubicin within mitochondria causes higher cytotoxicity and cell death compared to free doxorubicin. Endogenous enzyme triggered nanocapsule rupture and release of the encapsulated dye is also demonstrated in a zebrafish model. The results of this proof-of-concept study illustrate that NIPU nanocarriers can provide a site-specific delivery vehicle and improve the therapeutic efficacy of a drug or be used to produce organelle-specific imaging studies

Mitochondriotropic lanthanide nanorods : implications for multimodal imaging

Organelles such as mitochondria, lysosome, and nucleus, are essential for controlling basic cellular operations and metabolism. Because mitochondria play a critical role in energy production and programmed cell death, they act as prime therapeutic targets for various diseases and dysfunctional states. In this study, a multifunctional nanoplatform based on lanthanide upconverting nanorods is developed for concurrent mitochondria-targeted fluorescence imaging and preclinical MRI. This study provides critical insights into the spectral profiles of mitochondria and paves the way to developing novel, multimodal nanoprobes for mitochondria-targeted theranostics

Studies on structural variants within the cysteine proteinase superfamily

SIGLEAvailable from British Library Document Supply Centre-DSC:DX202530 / BLDSC - British Library Document Supply CentreGBUnited Kingdo

A fluorescent chemodosimeter for organelle-specific imaging of nucleoside polyphosphate dynamics in living cells

Nucleoside polyphosphates (NPPs) are mainly produced in mitochondria and used as a universal energy source for various cellular events. Although numerous fluorescent probes for adenosine triphosphate (ATP) have been reported, they are not ideally suited for live monitoring of the subtle variation of the mitochondrial ATP level. A new coumarin-based fluorescent probe is synthesized, and this reagent is utilized for specific recognition of NPPs in mitochondria by super-resolution microscopy in physiological condition. Detailed 31P NMR studies reveal that the probe, L·Zn(II), binds to NPPs through their pendent phosphate functionalities. Such binding leads to a substantial enhancement in the luminescence intensity of L·Zn(II) + ADP or L·Zn(II) + ATP as compared to L·Zn(II). This—as well as 1H NMR spectroscopy—has enabled us to evaluate the probe’s binding affinities to these NPPs. Structured illumination and wide field fluorescence microscopy confirmed that this physiologically benign reagent is localized within mitochondria of live RAW 264.7 macrophage cells. This reagent has been utilized to probe real-time changes in ATP concentrations within mitochondria during drug-induced apoptosis

Mitochondria Targeting Non-Isocyanate-Based Polyurethane Nanocapsules for Enzyme-Triggered Drug Release

Surface engineering of nanocarriers allows fine-tuning of their interactions with biological organisms, potentially forming the basis of devices for the monitoring of intracellular events or for intracellular drug delivery. In this context, biodegradable nanocarriers or nanocapsules capable of carrying bioactive molecules or drugs into the mitochondrial matrix could offer new capabilities in treating mitochondrial diseases. Nanocapsules with a polymeric backbone that undergoes programmed rupture in response to a specific chemical or enzymatic stimulus with subsequent release of the bioactive molecule or drug at mitochondria would be particularly attractive for this function. With this goal in mind, we have developed biologically benign nanocapsules using polyurethane-based, polymeric backbone that incorporates repetitive ester functionalities. The resulting nanocapsules are found to be highly stable and monodispersed in size. Importantly, a new non-isocyanate route is adapted for the synthesis of these non-isocyanate polyurethane nanocapsules (NIPU). The embedded ester linkages of these capsules’ shells have facilitated complete degradation of the polymeric backbone in response to a stimulus provided by an esterase enzyme. Hydrophilic payloads like rhodamine or doxorubicin can be loaded inside these nanocarriers during their synthesis by an interfacial polymerization reaction. The postgrafting of the nanocapsules with phosphonium ion, a mitochondria-targeting receptor functionality, has helped us achieve the site-specific release of the drug. Co-localization experiments with commercial mitotracker green as well as mitotracker deep red confirmed localization of the cargo in mitochondria. Our in vitro studies confirm that specific release of doxorubicin within mitochondria causes higher cytotoxicity and cell death compared to free doxorubicin. Endogenous enzyme triggered nanocapsule rupture and release of the encapsulated dye is also demonstrated in a zebrafish model. The results of this proof-of-concept study illustrate that NIPU nanocarriers can provide a site-specific delivery vehicle and improve the therapeutic efficacy of a drug or be used to produce organelle-specific imaging studies