Hematoxylin Nuclear Stain Reports Oxidative Stress via Near-Infrared Emission.

Hematoxylin & eosin (H&E) is the gold standard histological stain used for medical diagnosis and has been used for over a century. Herein, we examined the near-infrared II (NIR-II) fluorescence of this stain. We observed significant NIR-II emission from the hematoxylin component of the H&E stain.

Single-Chirality Near-Infrared Carbon Nanotube Sub-Cellular Imaging and FRET Probes.

Applications of single-walled carbon nanotubes (SWCNTs) in bioimaging and biosensing have been limited by difficulties with isolating single-chirality nanotube preparations with desired functionalities. Unique optical properties, such as multiple narrow near-infrared bands and several modes of signal transduction, including solvatochromism and FRET, are ideal for live cell/organism imaging and sensing applications. However, internanotube FRET has not been investigated in biological contexts.

Harnessing nanotechnology to expand the toolbox of chemical biology.

Although nanotechnology often addresses biomedical needs, nanoscale tools can also facilitate broad biological discovery. Nanoscale delivery, imaging, biosensing, and bioreactor technologies may address unmet questions at the interface between chemistry and biology. Currently, many chemical biologists do not include nanomaterials in their toolbox, and few investigators develop nanomaterials in the context of chemical tools to answer biological questions.

Polymer cloaking modulates the carbon nanotube protein corona and delivery into cancer cells.

Carbon nanotube-based molecular probes, imaging agents, and biosensors in cells and in vivo continue to garner interest as investigational tools and clinical devices due to their unique photophysical properties. Surface chemistry modulation of nanotubes plays a critical role in determining stability and interaction with biological systems both in vitro and in vivo. Among the many parameters that influence the biological fate of nanomaterials, surface charge is particularly influential due to direct electrostatic interactions with components of the cell membrane as well as proteins in the serum, which coat the nanoparticle surface in a protein corona and alter nanoparticle-cell interactions.

A Carbon Nanotube Optical Sensor Reports Nuclear Entry via a Noncanonical Pathway.

Single-walled carbon nanotubes are of interest in biomedicine for imaging and molecular sensing applications and as shuttles for various cargos such as chemotherapeutic drugs, peptides, proteins, and oligonucleotides. Carbon nanotube surface chemistry can be modulated for subcellular targeting while preserving photoluminescence for label-free visualization in complex biological environments, making them attractive materials for such studies. The cell nucleus is a potential target for many pathologies including cancer and infectious diseases.

Noncanonical amino acids to improve the pH response of pHLIP insertion at tumor acidity.

The pH low insertion peptide (pHLIP) offers the potential to deliver drugs selectively to the cytoplasm of cancer cells based on tumor acidosis. The WT pHLIP inserts into membranes with a pH50 of 6.1, while most solid tumors have extracellular pH (pH(e)) of 6.

pHLIP-FIRE, a cell insertion-triggered fluorescent probe for imaging tumors demonstrates targeted cargo delivery in vivo.

We have developed an improved tool for imaging acidic tumors by reporting the insertion of a transmembrane helix: the pHLIP-Fluorescence Insertion REporter (pHLIP-FIRE). In acidic tissues, such as tumors, peptides in the pHLIP family insert as α-helices across cell membranes. The cell-inserting end of the pHLIP-FIRE peptide has a fluorophore-fluorophore or fluorophore-quencher pair.

Measurement of heterogeneous reaction rates: three strategies for controlling mass transport and their application to indium-mediated allylations.

We describe three new strategies for determining heterogeneous reaction rates using photomicroscopy to measure the rate of retreat of metal surfaces: (i) spheres in a stirred solution, (ii) microscopic powder in an unstirred solution, and (iii) spheres on a rotating shaft. The strategies are applied to indium-mediated allylation (IMA), which is a powerful tool for synthetic chemists because of its stereoselectivity, broad applicability, and high yields. The rate-limiting step of IMA, reaction of allyl halides at indium metal surfaces, is shown to be fast, with a minimum value of the heterogeneous rate constant of 1 × 10(-2) cm/s, an order of magnitude faster than the previously determined minimum value.