Fluorescence and Luminescence

Inhibitory luminopsins: genetically-encoded bioluminescent opsins for versatile, scalable, and hardware-independent optogenetic inhibition. Nature.
Jack K. Tung, Claire-Anne Gutekunst, Robert E. Gross.

Eureka! Researchers at Georgia Tech may have solved the conundrum of how best to probe brains. Instead of surgically implanting optical fibers coupled to an external light source, as is the standard, neuroscientists may choose to have the brain glow in the dark. Utilizing bioluminescent proteins derived from sea pansies (a variety of polyp similar to the jellyfish), genetically-encoded opsin-expressing cells may become their own light source! This development is ground-breaking, as the current surgical method of manipulating neural activity via optogenetic techniques is beleaguered with risks and restrictions such as infection, limited range of motion, poor efficiency, and limitation of applicability of animal models. Inhibitory luminopsins have no such restrictions.

Figure 1: Glow in the dark cells. Oooo. The colors!

Metal-Enhanced Near-Infrared Fluorescence by Micropatterned Gold Nanocages. ACS Nano.
Camposeo A, Persano L, Manco R, Wang Y, Del Carro P, Zhang C, Li ZY, Pisignano D, Xia Y.

All that glitters IS gold, at least in the case of the Xia and Wang lab in the Coulter Department of Biomedical Engineering. In a recent publication, researchers have discovered a novel method of enhancing near-infrared fluorescence at a rate of 2-7 times with respect to the emission from pristine dyes. Increasing fluorescence is of interest, as near-infrared emission bands do not harm biomolecules, living cells, or tissues, making this development an important stepping stone in the field of proteomics and genomics.

Figure 1. (a) A schematic showing all major steps involved in the fabrication of MEF substrates based on Au nanocages: (i) microcontact printing of APTES, (ii) immobilization of Au nanocages on the regions covered by APTES, (iii) deposition of a SiO2 layer over the entire surface through e-beam evaporation, and (iv) deposition of an emissive layer to achieve a spatially resolved MEF. (b) Transmission electron micrograph of the Au nanocages. Scale bar: 100 nm. (c) Absorption (blue curve) and emission (red curve) spectra of the LD 700 dye, and extinction spectrum (black curve) of the nanocages. Inset: schematic illustration of the MEF and molecular structure of LD 700. l: the distance between an emitter and the surface of the Au nanocage