Si-DMA

Guidelines (The recommended experimental protocol below is for guidance only and should be adjusted according to your specific requirements)

1. Stock Solution Preparation
1.1 Solvent: DMSO.
1.2 Recommended concentrations: 50 nM, 100 nM; stock solutions without specified concentrations can also be prepared and stored at −20°C in the dark.

2. Working Solution Preparation
2.1 Diluent: Cell culture medium (Dulbecco's Modified Eagle Medium supplemented with 10% fetal bovine serum).
2.2 Working concentrations: 20-100 nM.
2.3 Notes: Adjust the working solution concentration as needed; prepare fresh immediately before use.

3. Staining Procedures
3.1 Sample Type Description
3.1.1 Adherent cells^[1][2][3][4]:
3.1.1.1 Sample types include HeLa cells, MDA-MB-231 cells, NIH3T3 mouse fibroblasts, HepG2 human hepatocellular carcinoma cells, and RAW 264.7 macrophages.
3.1.1.2 Trypsin digestion: Trypsin digestion is not required for most staining scenarios; it may be needed when collecting cells in related experiments.
3.1.1.3 Pre-staining collection steps: Some cell types require washing with phosphate-buffered saline prior to analysis.
3.1.1.4 Culture vessels: For some experiments, cells need to be cultured directly in glass-bottom μ-dish or μ-slide.
3.2 Incubation Conditions
3.2.1 Adherent cells: Incubate cells with Si-DMA solution at 37°C in a humidified environment containing 5% CO₂ for 30 min-1 h; some cell types require incubation with 50 nM Si-DMA for 45 min.
3.2.2 Adherent cells pre-treated with IRDI: First pre-incubate cells with IRDI for 3 h, then add Si-DMA and irradiate with a 405 nm laser to induce red fluorescence signals.
3.3 Washing Steps
3.3.1 Adherent cells: Wash cells twice with PBS before fluorescence imaging; alternatively, wash cells once with serum-free DMEM before staining and once with phosphate-buffered saline after staining; some cell types do not require washing steps.

4. Control Setup
4.1 Set up negative controls, positive controls, blank controls, and quencher controls according to experimental needs.
4.2 Negative controls:
4.2.1 Cells treated with DMSO.
4.2.2 Cells without IRDI treatment.
4.2.3 Cells incubated with Si-DMA only, without photosensitizer addition or light irradiation.
4.3 Positive control: Cells treated with 2 μM fungus-derived photosensitizing metabolite.
4.4 Blank control: Used to eliminate reagent fluorescence interference.
4.5 Quencher control: Cells co-incubated with Si-DMA, photosensitizer, and 1 mM/2 mM sodium azide (a singlet oxygen quencher).
4.6 Control validation: Positive controls are used to verify the validity of the experimental system.

5. Detection and Analysis
5.1 Instrument types: Fluorescence microscopes (including inverted fluorescence microscopes, objective-scanning confocal microscopes), flow cytometers.
5.2 Excitation/emission wavelengths: Excitation wavelength of 640 nm; emission wavelength of 655-725 nm (collected via a dichroic mirror and a 690/70 bandpass filter); red fluorescence is detected through the TRITC channel.
5.3 Result Analysis
5.3.1 Fluorescence characteristics: Red or far-red fluorescence is the characteristic signal for singlet oxygen detection; in pseudo-color imaging, a fluorescence intensity gradient from blue (low intensity) to red (high intensity) may be observed.
5.3.2 Changes in fluorescence intensity:
5.3.2.1 A continuous increase in fluorescence intensity can be observed within 10 min after cells are exposed to singlet oxygen-generating reagents^[1].
5.3.2.2 After reacting with singlet oxygen, the fluorescence intensity can increase by up to 17-fold; when singlet oxygen is generated by colocalized type II photosensitizers, the fluorescence intensity rises rapidly.
5.3.2.3 Fluorescence intensity increases in a dose-dependent manner after treatment with endoperoxides; it decreases in a dose-dependent manner after treatment with singlet oxygen quenchers.
5.3.2.4 Red fluorescence signals can only be detected in cells treated with IRDI and exposed to laser irradiation; no increase in fluorescence intensity is observed when using non-mitochondrially localized type II photosensitizers, type I photosensitizers, or other reactive oxygen species.
5.3.3 Fluorescence localization: It localizes selectively to mitochondria, presenting as elongated, branched fibrous structures, consistent with the subcellular sites of singlet oxygen generation.

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