英國研究人員開發(fā)出一種有助治療癌癥的納米微粒,。在光動力療法中,，它可以攜帶大量光敏分子進(jìn)入腫瘤，幫助殺滅癌細(xì)胞，其效果好于常規(guī)方法,。
光動力療法是指讓一些對光敏感的分子進(jìn)入到腫瘤中,，然后用光照射，這些光敏分子就會產(chǎn)生有毒物質(zhì)殺死癌細(xì)胞?，F(xiàn)在常通過血液注射的方式來輸送光敏分子,，但注射液中多是彼此分散的單個分子，這樣要使腫瘤部位出現(xiàn)較高的光敏分子含量就有難度,。
英國赫爾大學(xué)的研究人員在美國期刊《分子藥劑學(xué)》上報告說,，他們開發(fā)出一種直徑為幾十個納米大小的微粒，每個微?？梢詳y帶上百個光敏分子,，具有把光敏分子大量送達(dá)腫瘤部位的能力。在納米微粒的內(nèi)部和外部,，還可以攜帶兩種不同的光敏分子,，進(jìn)而增加光動力療法的效果。
研究人員羅斯·博伊爾說,，這種納米微粒的形狀經(jīng)過精心設(shè)計(jì),，能進(jìn)入腫瘤而不在健康組織中引起副作用。其原因是腫瘤中的血管與健康組織中的血管不太一樣,，其血管壁并不緊密,，存在一些“漏洞”，納米微?？梢栽谘獕和扑拖麓┻^這些“漏洞”進(jìn)入腫瘤,。
研究人員已經(jīng)用實(shí)驗(yàn)室培養(yǎng)的腫瘤組織進(jìn)行了實(shí)驗(yàn)，結(jié)果顯示這種納米微?？梢栽黾庸鈩恿Ο煼▽Π┘?xì)胞的殺傷力,。接下來研究人員將開展動物實(shí)驗(yàn)。（生物谷Bioon.com）
專題：MicroRNA 和 癌癥
生物谷推薦原文出處：
Mol. Pharmaceutics DOI: 10.1021/mp200023y
Polyacrylamide Nanoparticles as a Delivery System in Photodynamic Therapy
Maheshika Kuruppuarachchi, Huguette Savoie, Ann Lowry, Cristina Alonso, and Ross W. Boyle
Nanoparticles can be targeted towards, and accumulate in, tumor tissue by the enhanced permeability and retention effect, if sequestration by the reticuloendothelial system (RES) is avoided. The application of nanoparticles in the field of drug delivery is thus an area of great interest, due to their potential for delivering high payloads of drugs site selectively. One area which may prove to be particularly attractive is photodynamic therapy, as the reactive oxygen species (ROS) which cause damage to the tumor tissue are not generated until the drug is activated with light, minimizing generalized toxicity and giving a high degree of spatial control over the clinical effect. In the present study, we have synthesized two types of nanoparticles loaded with photodynamic sensitizers: polylysine bound tetrasulfonato-aluminum phthalocyanine entrapped nanoparticles (PCNP) and polylysine bound tetrasulfonato-aluminum phthalocyanine entrapped nanoparticles coated with a second, porphyrin based, photosensitizer (PCNP-P) to enhance the capacity for ROS generation, and hence therapeutic potential. The mean sizes of these particles were 45 ± 10 nm and 95 ± 10 nm respectively. Uptake of the nanoparticles by human Caucasian colon adenocarcinoma cells (HT29) was determined by flow cytometry and confocal microscopy. Cell viability assays using PCNP-P and PCNP corresponding to the minimum uptake time (<5 min) and maximum uptake time (25 h) demonstrated that these cancer cells can be damaged by light activation of these photodynamic nanoparticles both in the external media and after internalization. The results suggest that, in order to induce photodynamic damage, the nanoparticles need only to be associated with the tumor cell closely enough to deliver singlet oxygen: their internalization within target cells may not be necessary. Clinically, this could be of great importance as it may help to combat the known ability of many cancer cells to actively expel conventional anticancer drugs.
Keywords: PDT; porphyrins; phthalocyanine; nanoparticles; drug delivery
