Abstract

Objective

To determine whether photothermal polymer nanoparticles (NPs) can interface with bacteria associated with kidney stones, generate heat when stimulated with near infrared (NIR) light, and aid in reducing bacterial burden.

Methods

Two types of kidney stones, artificial, and those removed during percutaneous nephrolithotomy (PCNL), were inoculated with Escherichia coli (E. coli) and then incubated with NPs composed of FITC-labeled Poly[4,4-bis(2-ethylhexyl)-cyclopenta[2,1-b;3,4-b′]-dithiophene-2,6-diyl-alt-2,1,3-benzoselenadiazole-4,7-diyl] (PCPDTBSe). Association of the PCPDTBSe NPs was evaluated using fluorescence microscopy. Infected stones were incubated with NPs and exposed to 800 nm light to generate temperature increases from 25.4 to 68.6 °C on the stones. Following photothermal treatment, the stones were homogenized and the bacteria was enumerated via colony counting assays to evaluate the bactericidal effect. The photothermal effect was also evaluated using scanning electron microscopy of the treated biofilms.

Results

Both kidney stone types sequestered E. coli. Control stones and stones treated with laser only had growth of numerous bacterial colonies, while stones exposed to NPs and laser grew significantly less, or none (p = 0.02).

Conclusions

The polymer NPs interface with E. coli on artificial and patient-derived kidney stones, and they can impart a bactericidal effect, when stimulated with NIR to generate heat. This technique may possibly be extended to treating infected kidney stones in patients.

中文翻译：

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光热纳米粒子用于消融与肾结石相关的细菌

摘要

客观的

为了确定光热聚合物纳米颗粒（NPs）是否可以与与肾结石相关的细菌接触，在近红外（NIR）光刺激下产生热量并帮助减少细菌负担。

方法

用大肠杆菌（E. coli）接种两种类型的人造肾结石和经皮肾镜取石术（PCNL）去除的肾结石，然后与由FITC标记的Poly [4,4-bis（2-ethylhexyl）组成的NPs一起孵育-环戊[2,1-b; 3,4-b']-二噻吩-2,6-二基-alt-2,1,3-苯并硒二唑-4,7-二基]（PCPDTBSe）。使用荧光显微镜评估PCPDTBSe NP的缔合。将感染的结石与NP一起孵育，并暴露于800 nm的光下，使结石上的温度从25.4°C升高到68.6°C。经过光热处理后，将石头均质化，并通过菌落计数试验以评价杀菌效果。还使用处理过的生物膜的扫描电子显微镜评价了光热效应。

结果

两种肾结石类型都螯合了大肠杆菌。对照结石和经激光处理的结石仅具有许多细菌菌落的生长，而暴露于NPs和激光的结石则生长得少得多，甚至没有（p  = 0.02）。

结论

聚合物NPs在人工和患者来源的肾结石上与大肠杆菌接触，当受到NIR刺激产生热量时，它们可以发挥杀菌作用。该技术可能会扩展到治疗患者感染的肾结石。