Assays for determination of matrix metalloproteinases and their activity

Matrix metalloproteinases (MMPs) are involved in many physiological and pathological processes. Due to their ability to cleave and to remodel components of surrounding tissues, MMPs may affect cell migration, differentiation, growth, inflammatory processes, neovascularization, wound healing, apoptosis, the uterine cycle and many other actions within the body, including those needed for tumorigenesis and other diseases.MMPs can therefore be used as potential markers for detecting various cancers, neurodegenerative, and immune and cardiovascular diseases. Numerous MMP assays were developed for clinical and research purposes, but far more attention has been devoted to understanding their biological functions.Due to differences in methodology, results obtained in various laboratory settings are difficult to compare because of the lack of standards and analytical methods of validation. Limits of detection of particular methods used for identifying MMPs are also disputable.Enzymatic, immunochemical and fluorimetric methods are particularly suitable for clinical use. In-vivo imaging methods offer many potential advantages in cancer research and diagnostics. Other methods are subject to investigation [e.g., phage display, multiple-enzyme/multiple-reagent assay system (MEMRAS) and activity-based profiling].     

苯并噻唑类核酸分子荧光探针的合成及光谱性质

设计合成了3种两端杂环氮原子上具有不同取代基的苯并噻唑类不对称三甲川菁染料,并对染料的结构进行了表征。 测试了染料在乙醇中的吸收和荧光发射光谱,染料的最大吸收值和荧光发射值分别在629~635 nm和656~672 nm之间。 染料8、9和10的斯托克斯位移分别为23、37和27 nm。 染料在溶剂中基本无荧光,荧光量子产率小于0.021,可以极大的降低染料自身的荧光背景干扰。 染料的光降解实验表明,两端杂环氮原子苄基取代后可以明显增强染料的光稳定性。 测试循环伏安曲线得到染料的氧化电位分别为0.535、0.456和0.399 V,氧化电位越大,光降解速率常数越小,与光降解实验得到的降解速率常数结果一致。     

植被叶片光谱特征对烟煤病胁迫程度的响应模型研究

烟煤病是我国南方热带、亚热带地区一种非常普遍的植物病害,对我国农业生产造成巨大危害,对其监测预报是实施有效治理措施的重要基础和依据。为建立以高光谱数据为基础的烟煤病严重程度反演模型,在重庆北碚城区采集50个银木叶片样本,利用ASD FieldSpec HandHeld光谱仪获取高光谱数据,通过数码相机和ENVI软件获取叶面积数据,将银木叶片烟煤病面积与整个叶片面积的比例作为烟煤病的严重程度,建立相关性最大波段的烟煤病反演模型,探究烟煤病严重程度与光谱曲线之间可能存在的关系。结果表明： 单叶尺度下,健康叶片在560 nm波段附近有明显的反射峰,随着烟煤病严重程度增大,反射峰逐渐消失, 在可见光与近红外波段,总体上光谱反射率与烟煤病病情严重程度呈负相关性。500～650和720～850 nm为烟煤病的光谱敏感波段,其中相关度最大值点为550 nm波段,相关系数达到-0.72。在烟煤病严重程度与叶片波段原始光谱信息及多波段组合关系研究中,单叶尺度下785 nm波段高光谱参数与烟煤病严重程度建立的回归模型的决定系数(R2)最大,为0.875。通过模型的显著性检验和预测精度检验, 785nm 处的光谱反射率建立的二次曲线模型为最优。证明在单叶尺度下,基于785 nm波段的二次曲线模型反演烟煤病的效果较为理想。     

基于可见光光谱分析的黄瓜白粉病识别研究

白粉病是黄瓜常见病害之一,传播速度极快,严重时可造成黄瓜大量减产,对其进行快速准确识别,对黄瓜白粉病诊断和防治具有重要意义,应用可见光谱技术,结合主成分分析和支持向量机算法,实现对黄瓜白粉病的快速识别。配制白粉病菌孢子悬浮液,并人工接种于科研温室内的黄瓜叶片上,以诱发黄瓜白粉病,待白粉病有一定面积暴发后,利用海洋光学USB2000+型便携式光谱仪对黄瓜叶片光谱信息进行采集,利用五点取样法采集样本,在5个检查点,每点选取2株黄瓜进行调查,每株选取4枚感病叶片,每枚叶片随机选取5个感病区域进行光谱采集,共计采集200个感病叶片光谱样本,同样采集200个健康叶片样本作为对照。通过Ocean Optics Spectra-Suite软件采集漫反射标准白板信息和光谱仪暗电流实现光谱仪校正,调节积分时间、扫描次数以及平滑度等参数来实现光谱曲线平滑处理,以有效抑制光谱噪声,对光谱特征进行分类识别,去掉首尾噪声较大的波段,保留光谱的可见光波段进行研究,最终选取450~780 nm波段范围作为研究对象。利用主成分分析对所研究波段范围内的高维光谱数据（947维）进行降维处理,根据主成分的累计贡献率,选取前5个主成分作为分类模型的输入,以白粉病和健康叶片的判别结果作为输出,利用支持向量机算法,通过对样本的分类学习训练构建黄瓜白粉病和健康叶片的分类识别模型,随机选取120个样本作为训练集用于分类模型构建,其余80个样本作为测试集用于模型检验,并通过选取不同的核函数来获得最优模型。利用混淆矩阵对分类识别模型的准确率进行评价,当选取径向基核函数时,分类识别模型对黄瓜健康叶片和白粉病叶片的识别准确率最高,分别为100%和96.25%,总准确率为98.125%,具有较高的准确率。结果表明,利用可见光光谱信息并结合主成分分析和支持向量机算法,可以实现对黄瓜白粉病的快速准确识别,为黄瓜病害诊断提供了方法和参考依据。     

Electrical sensing of volatile organic compounds in exhaled breath for disease diagnosis

In recent years, electrical sensors toward breath volatolomics have attracted increasing interest owing to their wide feasibility in noninvasive disease diagnostics. In this article, the working principles of active nanomaterials (e.g. metal oxides, polymers, and nanocarbon) toward volatile organic compounds are presented, with a special focus on the influence of surface chemistry and structural feature of these nanomaterials on the sensing performance. The latest and representative achievements on the direct analysis of three typical exhaled volatile organic compounds, including acetone, ammonia, and hydrogen sulfide, that are recognized as important disease biomarkers, are highlighted, indicating the capability of the electrical sensors in enabling noninvasive diagnosis and real-time monitoring. The opportunities and challenges in this field are provided in the end, with an emphasis on the background interference and data recognition which are key factors in developing prospective electrical sensors toward volatolomics analysis.     

Recent ultrasound advancements for the manipulation of nanobiomaterials and nanoformulations for drug delivery

Recent advances in ultrasound (US) have shown its great potential in biomedical applications as diagnostic and therapeutic tools. The coupling of US-assisted drug delivery systems with nanobiomaterials possessing tailor-made functions has been shown to remove the limitations of conventional drug delivery systems. The low-frequency US has significantly enhanced the targeted drug delivery effect and efficacy, reducing limitations posed by conventional treatments such as a limited therapeutic window. The acoustic cavitation effect induced by the US-mediated microbubbles (MBs) has been reported to replace drugs in certain acute diseases such as ischemic stroke. This review briefly discusses the US principles, with particular attention to the recent advancements in drug delivery applications. Furthermore, US-assisted drug delivery coupled with nanobiomaterials to treat different diseases (cancer, neurodegenerative disease, diabetes, thrombosis, and COVID-19) are discussed in detail. Finally, this review covers the future perspectives and challenges on the applications of US-mediated nanobiomaterials.     

In vivo Self-assembled Peptide Nanoprobes for Disease Diagnosis

In vivo imaging is creating great opportunities for disease diagnosis as a research tool. Probes are usually used to observe physiological structures in vivo clearly. Recent progresses of nanoprobes are important for the generation of high resolution and high contrast images required by accurate and precision disease diagnosis. In vivo self-assembled peptide(SAP) nanoprobes are playing major roles in in vivo imaging by modularity of design, high imaging contrast, response to the location of the lesion, and long-time retention in the lesion. And the response to lesion and long-term retention in there can enhance imaging sensitivity and specificity of in vivo SAP nanoprobes. Therefore, in vivo SAP nanoprobes are simple ancillary contrast entities to optimize the imaging effect. In this review, the recent progress of in vivo SAP nanoprobes for in vivo imaging, from molecular design of peptides to biomedical and clinical applications including disease diagnosis and disease-related molecular imaging is systematically summarized. We evaluate their ability, including sensitivity and specificity to provide relevant information under preoperative and during surgery circumstances and critically their likelihood to be clinically translated. Finally, a brief outlook on remaining challenges and potential directions for future research in this area is presented.     

Functional assays in high-resolution clear native gels to quantify mitochondrial complexes in human biopsies and cell lines

We introduce high resolution clear native electrophoresis (CNE) as a powerful technique to resolve enzymatically active mitochondrial complexes from cultured human cell lines and skeletal muscle biopsy samples. Quantitative enzymatic assays can be performed using small amounts of cultured cells with low mitochondria content, for example, around 10 mg of sedimented osteosarcoma cells (wet weight) which is equivalent to around 10 million cells. High resolution CNE offers general advantages for in-gel catalytic activity assays compared to blue native electrophoresis. It seems especially suited for assaying mitochondrial ATP synthase and respiratory chain complexes I and II in cell models of human mitochondrial disorders and for detailed analyses of patient cells and tissues with defects in oxidative phosphorylation.     

基于马铃薯叶片光纤光谱信息的晚疫病患病程度预测

针对马铃薯晚疫病害的早期检测和防治问题,利用光谱技术对马铃薯晚疫病叶片过氧化物酶(POD)活性进行预测,并基于POD酶活性实现了马铃薯晚疫病的患病程度预测.采集和测定处于不同温湿度及接菌时间的马铃薯叶片样本的光谱反射率和POD酶活性,选用中心化(MC)预处理方法以消除原始光谱数据的误差.为降低模型复杂程度,利用随机青蛙...     

代谢组学分析技术及其在几类重大疾病研究中的应用

代谢组学正成为生物医学研究领域的新热点。各种代谢组学分析技术各有优缺点,配有低温探头的核磁共振、混合型串联傅里叶变换质谱以及多种联用技术将成为代谢组学研究的关键技术。目前,大量多维代谢组学数据的分析方法和专用软件急待开发完善。代谢组学在肿瘤,老年痴呆症、心血管疾病、肝肾脏类疾病等研究中的应用取得一定进展,疾病代谢组学具有良好的发展前景。