Rhodamine-labelled phosphatidylcholine (PC) liposomes are liposomes made by attaching a fluorescent agent, rhodamine (Rh-DHPE or Rh-DOPE), to phosphatidylcholine. They are common liposomes in biomedical research to monitor intracellular distribution, delivery of drugs, and cellular apposition. CliposTM rhodamine-labelled phosphatidylcholine (PC) liposomes are high-purity liposomes with a particle size of about 100 nm that are made by extrusion. These liposomes carry the fluorescent marker Rh-DHPE, and can be fluorescein microscopy and flow cytometry analyzed. These liposomes can also be used to analyse their subcellular localisation in different cell lines (BT-474, SK-BR-3). Preparation typically involves thin film hydration, in which lipids are dissolve in chloroform, dried to a thin film, rehydrated in a buffer and extruded on pore size 100 nm porous carbon membrane. This preparation procedure keeps the liposomes stable and uniform. They're mainly made of phosphatidylcholine, a phospholipid commonly found in cell membranes, to which the fluorescent molecule rhodamine is added. This combo not only makes the liposomes better but also offers a new way to monitor and visualize the drug delivery pathway. With the inclusion of rhodamine, researchers can now track how liposomes circulate and accumulate in biological systems live, giving a better picture of how they are biodistributed, absorbed by cells and transported within cells. This property is very helpful in preclinical studies where the exact behavior of the drug carriers are critical for the best possible therapeutic efficacy and safety.
Figure 1. Schematic representation of a liposome. (Luiz H, et al. 2023)
There are several advantages of delivering drugs in the form of rhodamine-tagged PC liposomes. Biocompatible and forming a stable bilayer, phosphatidylcholine holds many therapeutic molecules including hydrophilic, hydrophobic and amphiphilic molecules. Such liposomes are covered in a lipid bilayer like natural cell membranes and can fusion and be taken up by target cells. Further, rhodamine labelling doesn't make a radical change to the physicochemical composition of the liposomes so that the drug-delivery capability is retained. Rhodamine's fluorescence also makes imaging (fluorescence microscopy and flow cytometry) possible to follow liposomes in vitro and in vivo. This potential can be invaluable for shining a light on drug delivery networks and customising liposomes for optimal targeting efficiency and effectiveness. There are some novel drug-delivery possibilities too, with rhodamine-labelled PC liposomes. Phosphatidylcholine is biocompatible and has able to build stable bilayers where the different types of therapeutic molecules such as hydrophilic, hydrophobic, amphiphilic can be packed. The lipid bilayer of these liposomes (much like a cell membrane) stimulates fusion and capture by the ensuing cells. Moreover, rhodamine labelling has no effect on the liposomes' physicochemical composition at all, so they still carry drugs. With Rhodamine's fluorescence, it is possible to monitor liposome activity in vitro and live by many imaging techniques such as fluorescence microscopy and flow cytometry. This will help understand drug delivery mechanisms and optimise liposome design to provide more efficient and effective targeting.
Targeted drug delivery was one of the distinctive properties of rhodamine-labeled PC liposomes. By altering the surface of these liposomes with targeting ligands (eg, antibodies, peptides or small molecules), they can be attached to targeted cells or tissues to increase drug concentration at the target site without any off-target effects. This particular mode of targeting would be especially useful for cancer treatment where getting high levels of drug in tumour tissue without harming surrounding tissue is difficult. The direct validation of liposome targeting effectiveness and biodistribution via rhodamine fluorescence labelling allows scientists to optimise targeting before they go into the clinic. Moreover, using rhodamine-labelled PC liposomes in combination with other imaging techniques (MRI or CT, for example) can increase precision of drug delivery by adding additional information about the structure and function of the target tissue. Providing a means to deliver drugs using rhodamine-labelled PC liposomes also gives us an indicator of pharmacokinetics and pharmacodynamics of capsulated medicines. By following the fluorescent p-value of rhodamine, scientists can track how fast drugs leak from liposomes, how long they stay in the blood, and how quickly they're cleared out of the body. Such data is essential to create liposomal formulations that allow controlled, long-term delivery of therapeutic agents, decrease doses and enhance patient compliance. Visualisation of liposome interactions with physiologic obstacles (like the blood-brain barrier or intestinal epithelium) can be used to pinpoint possible inhibitors to delivery and develop strategies for conquering them as well. Also, PC liposomes with rhodamine labeling are available for theranostic applications, as diagnostic and therapeutic liposomes. Rhodamine's fluorescent nature allows for the non-invasive imaging of disease sites and real-time analysis of where and how pathology has developed. It is the capacity to coordinate therapies so that they go exactly where they're supposed to go. In cancer treatment, for instance, rhodamine-labelled liposomes allow surgeons to see tumor edges during surgery and remove the entire tumour. Those same liposomes could then be applied to remanufactured tumour cells to apply chemotherapy drugs, decreasing recurrence and increasing the effectiveness of the treatment. Apart from their cancer-related uses, rhodamine-tagged PC liposomes can also be used for other applications. In infectious diseases, for instance, such liposomes could take antibiotics or antivirals directly to the infection site, increasing the effectiveness of treatment and preventing drug resistance. In cardiovascular disease, they could be used to deliver drugs to the heart or blood vessels, increasing therapy efficacy and reducing systemic side effects. This portability makes rhodamine-labeled PC liposomes promising as an instrument of personalized medicine, where treatment is personalised to the needs and traits of each patient. The creation and optimization of rhodamine-labelled PC liposomes also needs to include a solid knowledge of their physicochemical composition, biological function and imaging properties. Scientists have to weigh carefully on liposome size and charge, stability of the rhodamine tag, and effectiveness of the medicine's encapsulation. This is then followed by dynamic light scattering, electron microscopy, fluorescence spectroscopy or any other advanced methods for identifying and checking these liposomes for purity and uniformity. Moreover, in vivo experiments would be needed to determine whether rhodamine-labelled PC liposomes are safe and effective, and whether they can be used in the clinic.
Alternate Names:
Rhodamine-Labeled PC Liposomes
Rhodamine-Phosphatidylcholine Liposomes
Rhodamine-Encapsulated PC Liposomes
Rhodamine-Tagged Phosphatidylcholine Liposomes
Rhodamine B Fluorescent Liposomes
Rhodamine-DHPE PC Liposomes
Rhodamine-Phospholipid Liposomes
Rhodamine Fluorescent Liposomes
References:
1. Luiz H, et al. Advancing Medicine with Lipid-Based Nanosystems-The Successful Case of Liposomes. Biomedicines. 2023, 11(2):435.
Datasheet