Characterization Of Novel Fluorescent Phospholipid Aggregates And Their Biomedical Applications

A cell membrane is mainly composed of phospholipids and self-assembled by phospholipids.Hence,phospholipid derivatives usually have excellent biocompatibility.Recently,phospholipid polymers have been widely used in biomedical fields such as drug delivery system,biomimetic coating,cell imaging,etc.This paper presented novel fluorescent phospholipid aggregates with strong green fluorescence.We also studied the properties of phospholipid aggregates and their application in the biomedical field.It was found that the emission wavelength of the phospholipid aggregates was 444 nm and the excitation wavelength was 336.5 nm.We hydrolyzed phospholipid aggregates to gain the hydrolysates with strong fluorescence,which were then purified by high performance liquid chromatography(HPLC).The particle size distribution of phospholipid aggregates at pH=5 was 30～40 nm,studied by dynamic light scattering.In the preliminary fluorescent bioimaging study on phospholipid aggregates,we found that 1mg/ml phospholipid aggregates(pH=5)could enter into NIH 3T3 cell nucleus after co-cultured with cells for 4 hours.When the phospholipid aggregates interacted with the cells for 12 hours,the cells underwent apoptosis.The half maximal inhibitory concentration of the phospholipid aggregates was 0.36 mg/ml.Because the pH value significantly affected the morphology of phospholipid aggregates,we employed serum free sodium citrate buffer solution system.In this system,0.6 mg/ml phospholipid aggregates(pH=5),co-cultured with the cells for 2 hours,could enter the nucleus.After 8 hours,the cells produced apoptosis.The half maximal inhibitory concentration of the phospholipid aggregates in the system was 0.24 mg/ml.The phospholipid aggregates were expected to be a novel biomaterial used in fluorescent labels.