Facile L-Glutamine delivery to erythrocytes via DOPC-DPPG mixed liposomes

Sickle cell disease (SCD) is a mortal erythrocyte-based disease which is hard to treat effectively. Development of a treatment method that can prevent deoxygenation of erythrocytes or reduce the oxidative stress of sickle erythrocytes is one of the important issues towards SCD. Among a wide variety of potential drug carriers, liposomes are advantageous and preferable with their easy preparation and biocompatibility. In this study, L-Glutamine (Gln) loaded liposomes were prepared with 1,2-Dioleoyl-sn-glycero-3-phosphocholine (DOPC) and 1,2-Dioleoyl-sn-glycero-3-phospho-rac-(1-glycerol) sodium salt (DPPG). Liposomes were characterized via zeta potential, size measurements, differential scanning calorimetry, Fourier Transform Infra-red Spectroscopy and they were visualized via transmission electron microscopy and scanning electron microscopy. Effect of the encapsulated amount of Gln was investigated by encapsulating Gln at three different concentrations (i.e0.20 mM, 40 mM and 60 mM). Drug encapsulation and release studies were implemented with high pressure liquid chromatography (HPLC). The encapsulation efficiency of Gln was determined to be the higher than the ones reported in the literature: 83.6%, 87.1% and 84.9% for 20 mM, 40 mM and 60 mM Gln, respectively. It was found that after 6 hours, liposomes loaded with 60 mM of Gln had released 45.7% of Gln. Optical microscopy images of the erythrocytes after 3 hours of incubation and haemolysis measurements proved that presence of liposomes did not cause any structural changes on the erythrocyte shape. Overall, it was concluded that L-Gln loaded PC/PG liposomes provide promising results in terms of developing a new drug delivery platform for SCD.

DNA-loaded microbubbles with crosslinked bovine serum albumin shells for ultrasound-promoted gene delivery and transfection

The microbubble is a kind of clinically applied ultrasound contrast agent in disease diagnosis that can also rupture under sonication to increase membrane permeability and promote gene entry into targeted cells. However, the development of ultrasound-mediated gene delivery might be restricted because genes and microbubbles were separated and would not reach the targeted cells simultaneously. Herein, a kind of crosslinked positive microbubbles (CPMBs) were prepared to load DNA as gene vectors to promote gene delivery efficiency. The BSA shell of the CPMBs was crosslinked with disulfide bonds, which obviously enhanced the stability of the CPMBs. Furthermore, the CPMBs revealed sonoporation effects comparable to those of clinically applied SonoVue microbubbles. As DNA and CPMBs were electrostatically linked as an entirety, they would reach cells simultaneously. Thus, with the aid of ultrasound, these DNA-loaded microbubbles promoted DNA entry into cytoplasm more effectively and obtained higher cellular uptake efficiency and better transfection efficiency than DNA-mixed microbubbles. Confocal microscopy results showed that rupturing of the CPMBs/DNA entire microbubbles under sonication could carry DNA directly into the cytoplasm or nucleus. All results indicated that the cytocompatible DNA-loaded microbubbles have promising prospects in ultrasound-mediated gene delivery.