Scientists at Indian Institute of Technology Indore, Indore have developed L-lyso—a novel water soluble, fluorescent dye which can permeate the membranes of lysosomes, marking them for future tracking and imaging.
Lysosomes are organelles found in almost every animal cell, and helps with the digestion of various biomolecules, macromolecules, old cell parts and microorganisms. The interiors of a lysosome is an acidic environment, with a variety of hydrolytic enzymes, which break down biomolecules, like nucleic acids, proteins and polysaccharides. Lysosomes are also considered as powerful indicators of various pathological disorders. The disorder could either affect the acid hydrolases within the lysosomes or cause genetic mutations, affecting the functioning of a lysosome. Such disorders, however, can be tracked by monitoring the lysosomes.
Conventionally, tools and dyes like LysoTracker are used as a marker. However these are often either expensive or are not efficient at tracking a lysosome for longer periods without losing their fluorescent properties. To overcome the limitations of conventional dyes, the team at IIT Indore developed L-lyso.
L-lyso is, according to the authors, “a new water soluble fluorescent Schiff-base ligand (L-lyso) containing two hydroxyl groups”. Here Schiff base refers to a class of compounds with a pre-defines structure and a sub-class of imines. Ligands are ions or molecules which are bound to a biomolecule to serve a biological purpose.
L-lyso is also said to display excellent two-photon properties. Two-photon excitation microscopy is a technique where, a subject is first marked with a fluorescent dye, and then illuminated with a source of light, generally in the near infra-red wavelength. The dye absorbs two photons of the incident IR light and begins to fluoresce, acting as a marker for the subject. The light also penetrates deep in to the subject, providing clear a image with deeper penetration. According to the authors “ L-lyso exhibits excellent two-photon properties with tracking of lysosomes in live cells as well as in 3D tumor spheroids”. L-lyso also remains active for 3 days, enabling tracking for longer periods.
The authors claim “L-lyso has an edge over the commercially available expensive LysoTracker probes and also over other reported probes in terms of its long-term imaging, water solubility and facile synthesis” talking about the superiority of L-lyso compared to conventional Lysosome trackers.