3 research outputs found
Ratiometric Imaging of Tissue by Two-Photon Microscopy: Observation of a High Level of Formaldehyde around Mouse Intestinal Crypts
Ratiometric
imaging by two-photon microscopy can offer a viable
tool for the relative quantification of biological analytes inside
tissue with minimal influence from environmental factors that affect
fluorescence signal. We demonstrate the ratiometric imaging of formaldehyde
at the suborgan level using a two-photon fluorescent probe, which
involves pixel-to-pixel ratiometric data transformation. This study
reveals for the first time a high level of formaldehyde around the
crypts of mouse small intestine, implicating its possible protective
role along with the released antimicrobials from the Paneth cells
Rapid Point-of-Care Quantification of Human Serum Albumin in Urine Based on Ratiometric Fluorescence Signaling Driven by Intramolecular H‑Bonding
Human
serum albumin exerts multifunctions, such as maintaining
the oncotic pressure of plasma, carrying hydrophobic molecules, and
acting as the most important antioxidant in the blood. Lower serum
albumin levels are linked to several cardiovascular diseases, and
dysfunction of albumin reabsorption in the kidney is linked to liver
disease, renal disorder, and diabetes. Albumin is thus a powerful
diagnostic and prognostic marker; however, its quantification in urine
by readily affordable tools is challenging owing to its very low concentration.
To address this issue, we developed a ratiometric fluorescent probe
with multiple advantages through a systematic structure variation
of a benzocoumarin fluorophore and, further, a prototype of a smartphone-based
point-of-care device. We determined albumin levels in urine and observed
that a smoking person has notably higher urine albumin than a nonsmoking
person. The cheap device provides a promising tool for albumin-associated
disease diagnosis in communities with limited resources
Two-Photon Absorbing Dyes with Minimal Autofluorescence in Tissue Imaging: Application to <i>in Vivo</i> Imaging of Amyloid‑β Plaques with a Negligible Background Signal
Fluorescence imaging of tissues offer
an essential means for studying
biological systems. Autofluorescence becomes a serious issue in tissue
imaging under excitation at UV–vis wavelengths where biological
molecules compete with the fluorophore. To address this critical issue,
a novel class of fluorophores that can be excited at ∼900 nm
under two-photon excitation conditions and emits in the red wavelength
region (≥600 nm) has been disclosed. The new π-extended
dipolar dye system shows several advantageous features including minimal
autofluorescence in tissue imaging and pronounced solvent-sensitive
emission behavior, compared with a widely used two-photon absorbing
dye, acedan. As an important application of the new dye system, one
of the dyes was developed into a fluorescent probe for amyloid-β
plaques, a key biomarker of Alzheimer’s disease. The probe
enabled <i>in vivo</i> imaging of amyloid-β plaques
in a disease-model mouse, with negligible background signal. The new
dye system has great potential for the development of other types
of two-photon fluorescent probes and tags for imaging of tissues with
minimal autofluorescence