Name: Labeling Amine-Functionalized Polystyrene Beads with TCPP
Uploaded: 2023-03-24T12:55:00
Description: Watch this Scientific Journal Video about Labeling Amine-Functionalized Polystyrene Beads with TCPP at JoVE.com

labeling amine-functionalized polystyrene beads with tcpp

Perle modificate con porfirina in citometria a flusso

Porphyrins have been of interest for many years in the biomedical field owing to their fluorescence and tumor-targeting properties1,2,3. Therapeutic applications such as photodynamic therapy (PDT) and sonodynamic therapy (SDT) entail the systemic administration of a porphyrin to a cancer patient, the accumulation of the drug in the tumor, and the localized exposure of the tumor to a laser light of a specific wavelength or ultrasound. The exposure to laser light or ultrasound leads to the generation of reactive oxygen species by the porphyrin and subsequent cell death4,5. In photodynamic diagnosis (PDD), porphyrin fluorescence is used to distinguish cancer cells from normal cells6. In this context, protoporphyrin IX, a natural fluorescent porphyrin that accumulates in tumors upon the systemic or local injection of its precursor, 5-aminolevulinic acid (5-ALA), is used to identify gastrointestinal stromal tumors, bladder cancer, and brain cancer7,8. More recently, 5-ALA treatment was explored as an approach to detect minimal residual disease in multiple myeloma9. Our laboratory has been using the tetraaryl porphyrin TCPP (5,10,15,20-tetrakis-(4-carboxyphenyl)-21,23H-porphine) for its ability to selectively stain lung cancer cells and cancer-associated cells in human sputum samples, which is a property that has been exploited in slide-based and flow cytometric diagnostic assays10.
Some porphyrins are bifunctional in that they can be used as therapeutic and diagnostic agents2,11. In biomedical research, such bifunctional porphyrins are used to evaluate how their ability to selectively target and kill cancer cells is a function of their structure as well as how it is affected by the presence of other compounds12,13,14,15,16. Both the cellular uptake of porphyrins and their cytotoxicity can be measured on a flow cytometric platform in a high-throughput manner. The absorption and emission spectra of fluorescent porphyrins are complex, but most flow cytometric platforms are equipped to correctly identify them. The absorption spectrum of fluorescent porphyrins is characterized by a strong absorption band in the 380-500 nm range, known as the Soret band. Two to four weaker absorption bands are generally observed in the 500-750 nm range (Q bands)17. A blue&#160;488 nm laser, present in most flow cytometers, or a violet laser (405 nm) can generate light of the appropriate wavelength to excite porphyrins. The emission spectra of porphyrins typically display peaks in the 600-800 nm range18, which results in very little spectral overlap with fluorescein isothiocyanate or phycoerythrin (PE) fluorophores but considerable overlap with other often-used fluorophores, such as allophycocyanin (APC), as well as tandem fluorophores, such as PE-Cy5 and others. Therefore, when using porphyrins in multi-color flow cytometry assays, single-fluorophore controls are essential to adequately correct the spillover of fluorescence in channels other than the one designated to measure the porphyrin&#39;s fluorescence.
Ideally, the single-fluorophore controls used to calculate the spillover matrix for a panel of fluorophores (also called &#34;compensation controls&#34;) should consist of the same cell type(s) as the sample. However, using the sample for this purpose is not optimal if there is very little sample to begin with or if the target population within the sample is very small&#160;(for example, if one wants to look at minimal residual disease or cancer cells at the early stages of the disease). A useful alternative to cells is beads coupled with the same fluorophore that is used to analyze the sample. Many such beads are commercially available; these beads are either prelabeled with the desired fluorophore (prelabeled fluorophore-specific beads)19,20, or a fluorescently labeled antibody can be attached to them (antibody capture beads)20,21. While commercial compensation beads are available for many fluorophores, such beads are unavailable for porphyrins, despite their increasing use in basic and clinical research.
In addition to sample preservation and appropriately sized positive versus negative populations, the other advantages of using beads as compensation controls are the ease of preparation, low background fluorescence, and excellent stability over time22. The potential disadvantage of using beads as a compensation control is that the emission spectrum of the fluorescent antibody captured on beads may differ from that of the same antibody used to label the cells. This may be of specific importance when using a spectral flow cytometer20. Therefore, the development of beads as a compensation control needs to be performed on the flow cytometer that will be used for the assay for which the beads are developed. Moreover, the development of the beads needs to include a comparison with cells labeled with the same fluorescent staining reagent.
Here, we describe the preparation of TCPP amine-functionalized polystyrene compensation beads, whose median fluorescence intensity in the detection channel was comparable to that of TCPP-labeled cells in sputum, and their use as compensation controls for flow cytometry. The autofluorescence of equivalent, non-functionalized beads was sufficiently low for their use as negative fluorescence compensation controls. In addition, these beads demonstrated stability in storage for nearly 1 year.

Autore in primo piano: Perle modificate con porfirina da utilizzare come controlli di compensazione nella citometria a flusso  

Perle modificate con porfirina da utilizzare come controllo di compensazione nella citometria a flusso

We developed polystyrene beads modified with the porphyrin TCPP as compensation controls and multicolor flow cytometry. The beads used in this protocol have fluorescence intensity comparable to TCPP stain cells and still passed through the flow cytometer. We accomplished that and are currently working on better methods to remove the particulate byproduct.Porphyrin-modified compensation beads were preferable to TCPP stained cells as compensation controls. These speeds were stable over months without significant loss of fluorescence. Porphyrins are known to stain cancer cells selectively.The research combines the selectivity of porphyrins with quantitative flow cytometry as a powerful platform for high-throughput analysis of human samples.

Watch this Scientific Journal Video about Labeling Amine-Functionalized Polystyrene Beads with TCPP at JoVE.com

Labeling Amine-Functionalized Polystyrene Beads with TCPP  

Etichettatura di perline di polistirene funzionalizzato con ammine con TCPP

Per iniziare, aggiungere 4,5 millilitri di soluzione di lavoro EDC appena preparata a un tubo di polipropilene da 15 millilitri contenente le perle di polistirene funzionalizzate con ammine e TCPP nel tampone MES. Posizionare il tubo in un rotatore invertente a 35 RPM per 16 ore a temperatura ambiente al riparo dalla luce. Quindi, centrifugare per 10 minuti.Aspirare il surnatante e risospendere le perle in 0,8 millilitri di soluzione salina bilanciata di Hank. Quindi, utilizzando una pipetta da un millilitro, trasferire la soluzione di perline in una fiala di polipropilene ambrato e conservarla a quattro gradi Celsius. La relazione tra la formazione di particolato, la mediana, l'intensità di fluorescenza o MFI e il rapporto tcp/EDC del tallone ha mostrato che con l'aumentare dei rapporti, l'IFM è aumentato fino a formare un plateau.Il particolato è apparso solo quando l'EDC è stato utilizzato come reagente di accoppiamento durante la procedura di etichettatura. L'etichettatura delle perle con TCPP da sola ha portato a un'intensità di fluorescenza molto più bassa. Quando le sfere marcate con TCPP sono state testate dopo 300 giorni, non è stato osservato alcun cambiamento significativo nell'MFI o nel contenuto di particolato.L'accoppiamento di TCPP alle perle ha avuto un effetto minimo sul suo spettro di emissione di fluorescenza. Tuttavia, il suo spettro differiva maggiormente dalle cellule tumorali polmonari A549 marcate con TCPP. In un campione di espettorato multi-flora a quattro marcature, le perle marcate con TCPP hanno funzionato altrettanto bene delle celle A549 colorate con TCPP.

Research

JoVE Journal

Chemistry

Labeling Amine-Functionalized Polystyrene Beads with TCPP

Porphyrin-Modified Beads for Use as Compensation Controls in Flow Cytometry

Flow cytometry can rapidly characterize and quantify diverse cell populations based on fluorescence measurements. The cells are first stained with one or ...

Ricerca

Chimica

Preparation of Meso-Tetra(4-Carboxyphenyl) Porphine (TCPP) Stock Solution

Preparazione della soluzione madre di porfina meso-tetra(4-carbossifenil) (TCPP)

Combining Amine-Functionalized Polystyrene Beads with TCPP Solution

Combinazione di perline di polistirene funzionalizzato con ammina con soluzione TCPP