Subcellular and in-vivo Nano-Endoscopy

Abstract

Analysis of individual cells at the subcellular level is important for understanding diseases and accelerating drug discovery. Nanoscale endoscopes allow minimally invasive probing of individual cell interiors. Several such instruments have been presented previously, but they are either too complex to fabricate or require sophisticated external detectors because of low signal collection efficiency. Here we present a nanoendoscope that can locally excite fluorescence in labelled cell organelles and collect the emitted signal for spectral analysis. Finite Difference Time Domain (FDTD) simulations have shown that with an optimized nanoendoscope taper profile, the light emission and collection was localized within ~100 nm. This allows signal detection to be used for nano-photonic sensing of the proximity of fluorophores. Upon insertion into the individual organelles of living cells, the nanoendoscope was fabricated and resultant fluorescent signals collected. This included the signal collection from the nucleus of Acridine orange labelled human fibroblast cells, the nucleus of Hoechst stained live liver cells and the mitochondria of MitoTracker Red labelled MDA-MB-231 cells. The endoscope was also inserted into a live organism, the yellow fluorescent protein producing nematode Caenorhabditis elegans, and a fluorescent signal was collected. To our knowledge this is the first demonstration of in vivo, local fluorescence signal collection on the sub-organelle level.

Nanobiotechnology medical applications: Overcoming challenges through innovation

“…These technologies will revolutionize in vitro assays and allow simple, non-invasive, inexpensive devices for patient-performed in-home diagnostics. A limiting factor off the chip technologies is that they only allow extracellular and surface-cellular detection, but another biosensing technology called nanoscale endoscopes allows subcellular detection of organelles and cytoplasmic biomarkers (82). The endoscope non-invasively probes a cell and photonically stimulates fluorescently tagged organelles to detect diseased cells based on individual intracellular signals (82).…”

“…A limiting factor off the chip technologies is that they only allow extracellular and surface-cellular detection, but another biosensing technology called nanoscale endoscopes allows subcellular detection of organelles and cytoplasmic biomarkers (82). The endoscope non-invasively probes a cell and photonically stimulates fluorescently tagged organelles to detect diseased cells based on individual intracellular signals (82). This technique provides insight into intracellular disease profiles, which will significantly aid in the development of future therapies.…”

Gut dysbiosis in stroke and its implications on Alzheimer’s disease‐like cognitive dysfunction

“…Transplantation of cells, microvesicles, microRNAs, and other molecules has encouraged the incorporation of peripheral therapeutic targets in organs other than the brain 7–10 . Characterizing gut and brain microbiomes, in addition to microbiomes located in other organs, using single‐cell omics and transcriptomics 11,12 will be the first step in elucidating the stroke pathology and progressing cell‐based therapeutic strategies along with other neurological diseases 7 . Furthermore, Parkinson's disease (PD) models have recently revealed the use of potent microbiomes both as a biomarker and therapeutic target, 13,14 shifting from brain‐focused neurological diagnosis and treatments to analysis of peripheral in the progression of PD 15 .…”

Templating Gold Nanoparticles on Nanofibers Coated with a Block Copolymer Brush for Nanosensor Applications

“…In cell endoscopy, small sub-micrometer probes such as glass pipettes, glass fibers, carbon nanopipettes, carbon nanotubes, nanowires, and atomic force microscopic tips are inserted into a cell noninvasively to perform various tasks such as intracellular sensing, delivery, plasmon phototherapy, electrochemistry, and electrophysiology at different locations of the cell with high spatial resolution. − A particular cell endoscopy probe utilizes surface enhanced Raman spectroscopy (SERS), owing to its superb sensitivity for detection of biochemicals in and around cells. − As proof of concept, Vitol et al demonstrated that the positioning of the 150 nm tip of a SERS-active glass pipette in the nucleus or in the cytoplasm of a HeLa cell yields clearly distinguishable spectra associated with both DNA and protein in the nucleus and the absence of DNA in the cytoplasm . Using a similar SERS nanopipette extracellularly, Lussier et al showed that the metabolic process of a living Madin–Darby canine kidney epithelial cell can be monitored in situ through the SERS detection of several metabolites .…”