Kostevšek Nina, Cheung Calvin C L, Serša Igor, Kreft Mateja Erdani, Monaco Ilaria, Comes Franchini Mauro, Vidmar Janja, Al-Jamal Wafa T
Department for Nanostructured Materials, Jožef Stefan Institute, 1000 Ljubljana, Slovenia.
School of Pharmacy, Queen's University Belfast, Belfast BT9 7BL, UK.
Nanomaterials (Basel). 2020 May 6;10(5):889. doi: 10.3390/nano10050889.
The majority of the clinically approved iron oxide nanoparticles (IO NPs) used as contrast agents for magnetic resonance imaging (MRI) have been withdrawn from the market either due to safety concerns or lack of profits. To address this challenge, liposomes have been used to prepare IO-based contrast agents. We studied the influence of different phospholipids on the relaxivity () values of magneto-liposomes (MLs) containing magnetic NPs in the bilayer, where a strong correlation between the bilayer fluidity and is clearly shown. Embedding 5-nm IO NPs in the lipid bilayer leads to a significant improvement in their relaxivity, where values range from 153 ± 5 s mM for DPPC/cholesterol/DSPE-PEG (96/50/4) up to 673 ± 12 s mM for DOPC/DSPE-PEG (96/4), compared to "free" IO NPs with an value of 16 s mM, measured at 9.4 T MRI scanner. In vitro MRI measurements, together with the ICP-MS analysis, revealed MLs as highly selective contrast agents that were preferentially taken up by cancerous T24 cells, which led to an improvement in the contrast and an easier distinction between the healthy and the cancerous cells. A careful selection of the lipid bilayer to prepare MLs could offer efficient MRI contrast agents, even at very low IO NP concentrations.
大多数临床上批准用作磁共振成像（MRI）造影剂的氧化铁纳米颗粒（IO NPs）已因安全问题或缺乏利润而退出市场。为应对这一挑战，脂质体已被用于制备基于IO的造影剂。我们研究了不同磷脂对双层中含有磁性纳米颗粒的磁脂质体（MLs）的弛豫率（）值的影响，其中清楚地显示了双层流动性与之间的强相关性。将5纳米的IO NPs嵌入脂质双层会导致其弛豫率显著提高，在9.4 T MRI扫描仪上测量时，对于DPPC/胆固醇/DSPE-PEG（96/50/4），值范围为153±5 s mM，对于DOPC/DSPE-PEG（96/4），值高达673±12 s mM，而“游离”IO NPs的值为16 s mM。体外MRI测量以及ICP-MS分析表明，MLs是高度选择性的造影剂，优先被癌性T24细胞摄取，这导致对比度提高，并且更容易区分健康细胞和癌细胞。精心选择脂质双层来制备MLs，即使在非常低的IO NP浓度下也能提供高效的MRI造影剂。
