FITC-Alginate

Operating Instructions (The following is a recommended experimental protocol for guidance only, and adjustments are required based on your specific needs)
1. Stock Solution Preparation
1.1 Solvents: Optional solvents include sodium bicarbonate solution at pH 8.5, deionized water/pure water, or phosphate-buffered saline (PBS) at pH 7.4.
1.2 Recommended Concentrations: Options include FITC-Alginate derivatives with 1.7 wt% FITC content, 3 wt% unlabeled alginate aqueous solution, 0.64% (w/v) FITC-Alginate, 2 wt% Alginate solution containing FITC-Alginate derivatives, or 1 mM FITC-Alginate.
2. Working Solution Preparation
2.1 Diluents: Optional diluents include 3 wt% unlabeled Alginate aqueous solution, cell culture medium containing 100 μM FeSO₄·7H₂O and 10 μM sodium ascorbate, deionized water, or 2% (w/v) Alginate solution.
2.2 Working Concentrations: Options include 0.04% (w/v) FITC-Alginate, FITC-Alginate derivatives mixed with 2 wt% unlabeled Alginate solution, or 0.6 μM FITC-Alginate.
2.3 Notes: Adjust the working solution concentration as needed; prepare fresh before use.
3. Staining Procedures
3.1 Sample Type Description
3.1.1 Applicable to Alginate hydrogel microspheres^[1]:
3.1.1.1 Incubation Conditions: Mix FITC-Alginate derivatives with unlabeled Alginate solution before microsphere preparation; cross-link the labeled alginate with 10 wt% calcium chloride solution for 20 min.
3.1.1.2 Washing Steps: Rinse the microspheres 3 times with deionized water via continuous centrifugation cycles.
3.1.2 Applicable to adherent cells (human RKO colon cancer cells)^[2]:
3.1.2.1 Incubation Conditions: Incubate cells (directly grown on sterile coverslips without trypsin digestion) with 0.04% (w/v) FITC-Alginate working solution for 24 hours.
3.1.3 Applicable to alginate microspheres (for embedding-based sensing detection)^[4]:
3.1.3.1 Incubation Conditions: Mix the sensing reagent with 2% (w/v) Alginate solution at a volume ratio of 1:10, and stir gently in the dark for 30 min.
3.1.3.2 Washing Steps: After core dissolution, centrifuge the microsphere suspension and wash twice with water to remove excess sodium citrate-Tris-HCl solution.
4. Control Setup
4.1 Negative Control: Incubate cells with iron-containing medium only (without FITC-Alginate).
4.2 Permeabilization Control: First permeabilize cells with 50 μg/mL Saponin (HY-100597), then incubate with FITC-Alginate working solution.
5. Detection and Analysis
5.1 Instrument Types: Confocal laser scanning microscope, confocal microscope, laser scanning confocal microscope, fluorescence spectrophotometer, fluorescence microscope.
5.2 Excitation/Emission Wavelengths: Excitation wavelength 488 nm, emission wavelength approximately 550 nm; excitation wavelength 490 nm, emission wavelength 515 nm; FITC-specific wavelengths.
5.3 Result Analysis
5.3.1 Fluorescence Visualization: Samples labeled with FITC-Alginate emit green fluorescence; the fluorescence distributes uniformly in Alginate hydrogel microspheres and micro-reservoirs; partially dissolved Alginate microspheres (for embedding-based sensing detection) show uneven fluorescence distribution; two-dimensional slice images of micro-reservoirs (from the surface to a depth of 100 μm) and three-dimensional reconstructed images, including deformation changes under tensile strain; TRITC emits red fluorescence in samples for embedding-based sensing detection.
5.3.2 Fluorescence Localization: Non-permeabilized adherent cells show only a very small amount of punctate green fluorescence at the cell edge, with no intracellular fluorescence; permeabilized adherent cells exhibit abundant green fluorescence inside the cells (mainly distributed in the cytoplasm).
5.3.3 Analytical Verification: A UV-visible spectrophotometer can be used to verify the successful synthesis of FITC-Alginate via the characteristic absorbance at 488 nm; in microspheres for embedding-based sensing detection, the FITC/TRITC fluorescence intensity ratio increases with the rise of glucose concentration.

MedChemExpress (MCE) has not independently confirmed the accuracy of these methods. They are for reference only.