基于双链特异性核酸酶触发滚环扩增的microRNA-21太赫兹超材料传感方法的构建

目的:构建一种太赫兹(THz)超材料传感方法用于microRNA-21(miRNA-21)的信号放大检测。方法:首先构建THz超材料传感方法,并用聚丙烯酰胺凝胶电泳及zeta电位验证方法的可行性;对传感器检测条件进行优化之后,对不同浓度的miRNA-21以及其他不同的miRNAs进行检测,并与其他microRNA检测方法进行比较;最后,对该传感器的回收率进行了评价。结果:在最优实验条件下,通过双链特异性核酸酶(DSN)循环识别与滚环扩增(RCA)的双重信号放大策略,该THz超材料传感器对靶标miRNA-21的响应范围为10 fmol/L至10 nmol/L,检测限为8.49 fmol/L。并且该传感器具有较好的特异性,具备了从多种miRNAs中识别靶标miRNA-21的能力,并且在商业化人血清样本中的回收率可达94.33%到115.33%。结论:该THz传感器可以实现靶标miRNA-21的高灵敏、高特异性检测,具备了在miRNA相关疾病无标记诊断与早期预警的潜力。     

In-vitro tomography and non-destructive imaging at depth of pharmaceutical solid dosage forms

Tomographic imaging techniques offer new prospects for a better understanding of the quality, performance and release mechanisms of pharmaceutical solid dosage forms. It is only over the last fifteen years that tomography has been applied for the in-vitro characterisation of dosage forms. This review aims to introduce the concept of tomography in a pharmaceutical context, and describes the current state-of-the-art of the four most promising techniques: X-ray computed microtomography, magnetic resonance imaging, terahertz imaging and optical coherence tomography. The basic working principles of the techniques are introduced and the current pharmaceutical applications of the technologies are discussed, together with a comparison of their specific strengths and weaknesses. Possible future developments in these fields are also discussed.     

太赫兹波对MG-63荷瘤小鼠快速活体成像的实验研究

摘要 [目的]实验研究太赫兹波对人成骨肉瘤细胞株MG-63荷瘤小鼠活体体内恶性肿瘤组织能否显像及其特异性,并探讨太赫兹波技术在骨肉瘤肿瘤组织切除术中的指导作用。[方法]利用华中科技大学光电国家重点实验室连续太赫兹成像系统,进行人成骨肉瘤细胞株MG-63荷瘤小鼠活体的THz波显像,并在活体成像指导下进行瘤体切除术（实验组）与肉眼下行瘤体切除术（对照组）再次检测进行对比,术中取出组织送病理切片;将术后人成骨肉瘤MG-63荷瘤小鼠继续饲养一周后再次行THz波显像。[结果]活体人成骨肉瘤MG-63荷瘤小鼠体内瘤体组织处出现强烈吸收信号,与周围组织差异明显;术后THz波显像及病理切片均显示太赫兹波指导下行瘤体切除术比肉眼下行瘤体切除术更为彻底;继续饲养一周后对照组荷瘤小鼠原位再次复发。[结论]太赫兹波技术能对人成骨肉瘤细胞株MG-63荷瘤小鼠中肿瘤组织特异性显像,且能良好指导手术切除恶性肿瘤组织,有望在临床中应用。     

A Fast and Non-destructive Terahertz Dissolution Assay for Immediate Release Tablets

There is a clear need for a robust process analytical technology tool that can be used for on-line/in-line prediction of dissolution and disintegration characteristics of pharmaceutical tablets during manufacture. Tablet porosity is a reliable and fundamental critical quality attribute which controls key mass transport mechanisms that govern disintegration and dissolution behavior. A measurement protocol was developed to measure the total porosity of a large number of tablets in transmission without the need for any sample preparation. By using this fast and non-destructive terahertz spectroscopy method it is possible to predict the disintegration and dissolution of drug from a tablet in less than a second per sample without the need of a chemometric model. The validity of the terahertz porosity method was established across a range of immediate release (IR) formulations of ibuprofen and indomethacin tablets of varying geometries as well as with and without debossing. Excellent correlation was observed between the measured terahertz porosity, dissolution characteristics (time to release 50% drug content) and disintegration time for all samples. These promising results and considering the robustness of the terahertz method pave the way for a fully automated at-line/on-line porosity sensor for real time release testing of IR tablets dissolution.     

Hyphenated spectroscopy as a polymorph screening tool

Polymorph screening of a model compound (nitrofurantoin) was performed. Nitrofurantoin was crystallized from acetone-water mixtures with varying process parameters. Two anhydrate forms (alpha and beta) and one monohydrate form (II) were crystallized in the polymorph screen. The solid forms were analyzed with three complementary spectroscopic techniques: near-infrared (NIR) spectroscopy, Raman spectroscopy and terahertz pulsed spectroscopy (TPS), and the results of the solid phase analysis were verified with X-ray powder diffraction (XRPD). NIR and Raman spectroscopy were coupled to achieve a rapid and comprehensive method of solid phase analysis. The hyphenated NIR/Raman spectroscopic data were analyzed with a multivariate method, principal component analysis (PCA). The combination was found effective in screening solid forms due to the complementary characteristics of the methods. NIR spectroscopy is powerful in differentiating between anhydrate and hydrate forms and intermolecular features, whereas Raman spectroscopy is sensitive to intramolecular alterations in the molecular backbone.     

Terahertz pulsed imaging and near infrared imaging to monitor the coating process of pharmaceutical tablets

Terahertz pulsed imaging (TPI) and near infrared (NIR) imaging were used to non-destructively monitor the coating process of film-coated tablets. Samples that were taken from a pan coater at different time points were analyzed by both methods. TPI provided coating thickness maps over the whole surface of the tablets, determining the thickness of the coating at each point of the sample surface in μm, this way also giving information about the coating uniformity. The growth of the coating during the coating process was shown. NIR imaging did not provide direct thickness values, but by different absorbance values, inter- and intra-tablet differences were shown. Thus, coating thickness information was also obtained in a way that different tablets could be compared. The growth of the coating layer during the process was shown as well. Both methods provided comparable results; and they were able to detect small defects in the coating. With TPI, the whole tablet surface could be scanned; with NIR imaging information about the tablet ends at the center-band was not obtained due to the strong curvature. NIR imaging proved to be better at thinner coating layers and had a higher spatial resolution whereas TPI had the clear advantage that it provided direct thickness values.     

Evaluating the effect of coating equipment on tablet film quality using terahertz pulsed imaging

In this study, terahertz pulsed imaging (TPI) was employed to investigate the effect of the coating equipment (fluid bed and drum coater) on the structure of the applied film coating and subsequent dissolution behaviour. Six tablets from every batch coated with the same delayed release coating formulation under recommended process conditions (provided by the coating polymer supplier) were mapped individually to evaluate the effect of coating device on critical coating characteristics (coating thickness, surface morphology and density). Although the traditional coating quality parameter (weight gain) indicated no differences between both batches, TPI analysis revealed a lower mean coating thickness (CT) for tablets coated in the drum coater compared to fluid bed coated tablets (p < 0.05). Moreover, drum coated tablets showed a more pronounced CT variation between the two sides and the centre band of the biconvex tablets, with the CT around the centre band being 22.5% thinner than the top and bottom sides for the drum coated tablets and 12.5% thinner for fluid bed coated tablets. The TPI analysis suggested a denser coating for the drum coated tablets. Dissolution testing confirmed that the film coating density was the drug release governing factor, with faster drug release for tablets coated in the fluid bed coater (98 ± 4% after 6 h) compared to drum coated tablets (72 ± 6% after 6 h). Overall, TPI investigation revealed substantial differences in the applied film coating quality between tablets coated in the two coaters, which in turn correlated with the subsequent dissolution performance.     

基于时域太赫兹波谱法的降糖类药物分类与分析

目的根据降糖类药物在太赫兹频域范围的吸收光谱,研究他们各自基团的振动频率及其共振峰,以有效鉴别各种相似药品,同时也为明确不同分子基团振荡在药理上的贡献打下基础。方法利用时域太赫兹波谱系统对格列喹酮、格列吡嗪、格列齐特、格列美脲、瑞格列奈和二甲双胍6种降糖药进行检测,得到他们在0.3～3.0 THz范围内的吸收谱;同时选取1.5～2.0 THz范围内的分类特征数据,用支持向量机的方法,分别对这些降糖药的特征数据进行鉴别。结果 4种磺脲类降糖药都在1.37 THz处有一明显的共振峰。根据吸收谱,能够很轻易地区分出瑞格列奈和二甲双胍与磺脲类药物的差别;而在支持向量机的帮助下,4类磺脲类药物也可被100%准确区分出来。结论太赫兹作为一种新的检测手段,在药物鉴别、药物品质控制、化学键/功能基团识别等方面有着积极的意义。     

Pattern identification of biomedical images with time series: Contrasting THz pulse imaging with DCE-MRIs

ObjectiveWe provide a survey of recent advances in biomedical image analysis and classification from emergent imaging modalities such as terahertz (THz) pulse imaging (TPI) and dynamic contrast-enhanced magnetic resonance images (DCE-MRIs) and identification of their underlining commonalities.MethodsBoth time and frequency domain signal pre-processing techniques are considered: noise removal, spectral analysis, principal component analysis (PCA) and wavelet transforms. Feature extraction and classification methods based on feature vectors using the above processing techniques are reviewed. A tensorial signal processing de-noising framework suitable for spatiotemporal association between features in MRI is also discussed.ValidationExamples where the proposed methodologies have been successful in classifying TPIs and DCE-MRIs are discussed.ResultsIdentifying commonalities in the structure of such heterogeneous datasets potentially leads to a unified multi-channel signal processing framework for biomedical image analysis.ConclusionThe proposed complex valued classification methodology enables fusion of entire datasets from a sequence of spatial images taken at different time stamps; this is of interest from the viewpoint of inferring disease proliferation. The approach is also of interest for other emergent multi-channel biomedical imaging modalities and of relevance across the biomedical signal processing community.     

不同芽孢杆菌的太赫兹时域光谱特征研究

目的 应用太赫兹时域光谱技术对常见致病芽孢杆菌进行检测.方法 使用太赫兹时域光谱技术对枯草芽孢杆菌、蜡状芽孢杆菌、苏云金芽孢杆菌3种致病菌进行了室温、干燥环境下太赫兹时域光谱测试.得到了样品在0.2 ～2.0 THz波段的太赫兹吸收曲线.结果 随着频率增加不同含量的芽孢杆菌冻干粉的太赫兹波段的吸收系数是增加的,并且有不同的吸收趋势;此外不同种属的芽孢杆菌的冻干粉和菌落也具有明显不同的吸收系数,这意味着3种样品的分子及官能团的构成和存在状态是不同的,更有力地揭示3种样品的确具有不同的生物成分组成和结构.结论 太赫兹时域光谱技术作为一种快速高效、无需标记且无破坏性的探测方法,为芽孢杆菌的检测和鉴别提供了一种行之有效的方法.