Cancer cells secrete copious amounts of secretory granules, exosomes, proteases. Recently, studies reviewed that mast cells (MCs) play crucial roles in the growth, spread and metastasis of tumor. MCs are one of the earliest cell types to infiltrate developing tumors. MCs undergo degranulation in response to various stimuli and rapidly release diverse bioactive mediators, such as histamine, tryptase, serotonin, tumor necrosis factor α (TNFα), which will tremendously affect the tumor microenvironment (TME). However, the mechanisms between the secretion of MCs degranulation and tumor remain unclear. Therefore, we developed a nanobiosensor based on fluorescence resonance energy transfer (FRET) for the determination of P815 mast cells and HeLa cells by secretagogues. With the pep-FITC as an energy donor and reduced grapheme oxide (rGO) as an energy acceptor, the two parts assemble an efficient FRET biosensor through electrostatic and stacking interaction (- interaction). Sensitized secretory cells can produce tryptase which would hydrolyze the specific cleavage site of the peptide, leading to ruin FRET system and then yield intensive fluorescence (FL) recovery of quenched FITC. Results showed that P815 cells are more sensitive and intense secretory than HeLa cells owing to more amount secretory mediators of P815 can change the microenvironment and further exacerbate the degree of degranulation in return. Our findings suggest that FRET biosensor have the ability to detect the extracellular dynamics of the cancer cells microenvironment. In addition, targeting mast cells may serve as a novel therapeutic scheme for cancer treatment and that inhibiting mast cell function may lead to tumor regression.
Degranulation in mast cell is usually characterized by the release of tryptase. We developed a fluorescence resonance energy transfer (FRET) probe based on graphene oxide (GO) to detect tryptase released from mast cells. The GO based FRET probe is composed of GO and a self-assembled complex of tryptase-specific recognition peptide chains labeled with isothiocyanate fluorescein. The fluorescence intensity around the mast cells increased when the mast cells were stimulated with C48/80, a kind of reagent promoting degranulation. The fluorescence distribution is inhomogenous. The fluorescence intensity was dependent on the concentration of C48/80 and the stimulation time. These results demonstrate that GO-base FRET probe could be used to study degranulation in mast cells.
Adenosine plays important roles in the pain signal transduction by activating adenosine receptors of two subtypes of A<sub>1</sub> and A<sub>2</sub><sub>A</sub>. In this study, FRET system based independent emission -spectral spectral spectral unmixing method (Iem-spFRET) was set up and used to measure the energy transfer from A<sub>1</sub>R to A<sub>2A</sub>R. The energy transfer efficiency calculated by Iem-spFRET is about 17.44%. All the above date and results demonstrate that FRET with special designed fluorescence proteins could be used to investigate the interaction between adenosine receptors.
Human hair is a keratinous tissue composed mostly of flexible keratin, which can form a complex architecture consisting of distinct compartments or units (e.g. hair bulb, inner root sheath, shaft). Variations in hair shaft morphology can reflect ethnical diversity, but may also indicate internal diseases, nutritional deficiency, or hair and scalp disorders. Hair shaft abnormalities in cross section and diameter, as well as ultramorphological characterization and follicle shapes, might be visualized non-invasively by high-speed 2D and 3D optical coherence tomography (OCT). In this study, swept source OCT (ThorLabs) was used to examine human hair. Preliminary results showed that the high-speed OCT was a suitable and promising tool for non-invasive analysis of hair conditions.