Mechanistic adaptability of cancer cells strongly affects anti-migratory drug efficacy

Cancer metastasis involves the dissemination of cancer cells from the primary tumour site and is responsible for the majority of solid tumour-related mortality. Screening of anti-metastasis drugs often includes functional assays that examine cancer cell invasion inside a three-dimensional hydrogel that mimics the extracellular matrix (ECM). Here, we built a mechanically tuneable collagen hydrogel model to recapitulate cancer spreading into heterogeneous tumour stroma and monitored the three-dimensional invasion of highly malignant breast cancer cells, MDA-MB-231. Migration assays were carried out in the presence and the absence of drugs affecting four typical molecular mechanisms involved in cell migration, as well as under five ECMs with different biophysical properties. Strikingly, the effects of the drugs were observed to vary strongly with matrix mechanics and microarchitecture, despite the little dependence of the inherent cancer cell migration on the ECM condition. Specifically, cytoskeletal contractility-targeting drugs reduced migration speed in sparse gels, whereas migration in dense gels was retarded effectively by inhibiting proteolysis. The results corroborate the ability of cancer cells to switch their multiple invasion mechanisms depending on ECM condition, thus suggesting the importance of factoring in the biophysical properties of the ECM in anti-metastasis drug screenings.     

Systems approaches to uncovering the contribution of environment-mediated drug resistance

Cancer drug response is heavily influenced by the extracellular matrix (ECM) environment. Despite a clear appreciation that the ECM influences cancer drug response and progression, a unified view of how, where, and when environment-mediated drug resistance contributes to cancer progression has not coalesced. Here, we survey some specific ways in which the ECM contributes to cancer resistance with a focus on how materials development can coincide with systems biology approaches to better understand and perturb this contribution. We argue that part of the reason that environment-mediated resistance remains a perplexing problem is our lack of a wholistic view of the entire range of environments and their impacts on cell behavior. We cover a series of recent experimental and computational tools that will aid exploration of ECM reactions space, and how they might be synergistically integrated.     

Status of engineering change management in the engineer-to-order production environment: insights from a multiple case study

Engineering Changes (ECs) are a fact of life for companies in the Engineer-To-Order (ETO) production environment. Various Engineering Change Management (ECM) strategies, practices and tools exist, but no explicit distinction has been made regarding ECM in different production environments. Using a multiple case study method, this article investigates how ETO companies manage ECs and how ETO characteristics influence ECM. A generic ECM framework was developed and used to map ECM in the cases. The study showed that ETO companies use similar practices for handling ECs, while ECM tools are either not used by the companies or used to a very limited extent. It was found that the use of some ECM practices and tools is complicated by specific ETO company characteristics. However, no reasons were found for the lack of computer-based tools, change propagation and impact assessment tools, change reduction and front-loading tools, and design tools. This suggests, firstly, that there is vast room for improvement in ETO companies when it comes to ECM; and secondly, that the applicability of such tools should be further tested in the ETO environment. Based on the findings, some suggestions as to how ECM can be improved in ETO companies are given to practitioners.     

Differential absorption sensor applied for liquid oxygen measurements

Differential laser absorption was investigated for its merit in liquid oxygen (LOX) sensing. Whereas previous researchers have used differential absorption to detect trace concentrations of a substance, we use differential absorption to monitor small changes in large amounts of a substance. Two lasers of different wavelengths were intensity modulated 180 deg out of phase from each other and multiplexed into a single beam. After probing the LOX, the total transmitted signal was demodulated by a lock-in amplifier. Our experiment simulated rapid changes in LOX number density by varying the length of an approximately 73 mm path through pure LOX. In this experiment, we demonstrated the ability to monitor LOX number density with an uncertainty of approximately 1% with a time constant of 3 micros. The uncertainty could be halved by doubling the path length, and this improvement could be repeated as long as the relative intensity noise of the lasers is the dominating factor. We discuss the benefits of differential absorption for problems requiring an extended dynamic range.     

Application of the effective crack method to mode I and mode II interlaminar fracture of carbon/epoxy unidirectional laminates

This paper describes an experimental study involving double cantilever beam (DCB), end-notched flexure (ENF) and four-point end-notched flexure (4ENF) tests on carbon/epoxy unidirectional specimens. The main purpose was to evaluate the so-called effective crack method (ECM), which avoids operator crack position monitoring. Extensive fibre bridging in DCB tests made the ECM inappropriate, as shown in subsequent finite element analyses. On the other hand, the ECM gave very consistent results from ENF tests, despite the usually unstable initiation. The present results confirmed some dependence of perceived initiation toughness values on ENF specimen geometry predicted in recent numerical studies. Differences between results of ENF and 4ENF tests could be explained by friction effects in the latter.     

Liquid oxygen liquid acquisition device bubble point tests with high pressure lox at elevated temperatures

When transferring propellant in space, it is most efficient to transfer single phase liquid from a propellant tank to an engine. In earth’s gravity field or under acceleration, propellant transfer is fairly simple. However, in low gravity, withdrawing single-phase fluid becomes a challenge. A variety of propellant management devices (PMDs) are used to ensure single-phase flow. One type of PMD, a liquid acquisition device (LAD) takes advantage of capillary flow and surface tension to acquire liquid. The present work reports on testing with liquid oxygen (LOX) at elevated pressures (and thus temperatures) (maximum pressure 1724 kPa and maximum temperature 122 K) as part of NASA’s continuing cryogenic LAD development program. These tests evaluate LAD performance for LOX stored in higher pressure vessels that may be used in propellant systems using pressure fed engines. Test data shows a significant drop in LAD bubble point values at higher liquid temperatures, consistent with lower liquid surface tension at those temperatures. Test data also indicates that there are no first order effects of helium solubility in LOX on LAD bubble point prediction. Test results here extend the range of data for LOX fluid conditions, and provide insight into factors affecting predicting LAD bubble point pressures.     

Multi-compartment tumor organoids

Organoid cultures are widely used for tumor modeling because they preserve many phenotypic features of cancer cells in vivo. However, current organoids present issues of consistency, efficiency, mimicry, and cell-seeding control. More importantly, they can only contain only one extracellular matrix (ECM) compartment at a time, while solid tumors feature two main ECM compartments: the basement membrane and the stromal matrix. Here, we develop, test, and validate a high-throughput oil-in-water droplet microtechnology to generate highly uniform, small-volume, multi-compartment organoids. Each organoid culture features microenvironmental architectures that mimic both the basement membrane and stromal barriers. This matrix architecture, which allows us to simultaneously take into account and assess the proliferative and invasive properties of cancer cells in a single platform, has profound effect on observed drug responsiveness and tumor progression that correlate well with in vivo and clinical outcomes. Our method was tested on multiple types of cells including primary breast and ovarian cancer cells and immortalized cell lines, and we determined our platform is suitable even for cancer cells of poor standard organoid-forming ability such as primary patient samples. These new organoids also allow for direct orthotopic mouse implantation of cancer cells with unprecedented success.     

Recapitulating tumour microenvironment in chitosan–gelatin three-dimensional scaffolds: an improved in vitro tumour model

Owing to the reduced co-relationship between conventional flat Petri dish culture (two-dimensional) and the tumour microenvironment, there has been a shift towards three-dimensional culture systems that show an improved analogy to the same. In this work, an extracellular matrix (ECM)-mimicking three-dimensional scaffold based on chitosan and gelatin was fabricated and explored for its potential as a tumour model for lung cancer. It was demonstrated that the chitosan–gelatin (CG) scaffolds supported the formation of tumoroids that were similar to tumours grown in vivo for factors involved in tumour-cell–ECM interaction, invasion and metastasis, and response to anti-cancer drugs. On the other hand, the two-dimensional Petri dish surfaces did not demonstrate gene-expression profiles similar to tumours grown in vivo. Further, the three-dimensional CG scaffolds supported the formation of tumoroids, using other types of cancer cells such as breast, cervix and bone, indicating a possible wider potential for in vitro tumoroid generation. Overall, the results demonstrated that CG scaffolds can be an improved in vitro tool to study cancer progression and drug screening for solid tumours.     

Precise and Arbitrary Deposition of Biomolecules onto Biomimetic Fibrous Matrices for Spatially Controlled Cell Distribution and Functions

Advances in nano‐/microfabrication allow the fabrication of biomimetic substrates for various biomedical applications. In particular, it would be beneficial to control the distribution of cells and relevant biomolecules on an extracellular matrix (ECM)‐like substrate with arbitrary micropatterns. In this regard, the possibilities of patterning biomolecules and cells on nanofibrous matrices are explored here by combining inkjet printing and electrospinning. Upon investigation of key parameters for patterning accuracy and reproducibility, three independent studies are performed to demonstrate the potential of this platform for: i) transforming growth factor (TGF)‐β1‐induced spatial differentiation of fibroblasts, ii) spatiotemporal interactions between breast cancer cells and stromal cells, and iii) cancer‐regulated angiogenesis. The results show that TGF‐β1 induces local fibroblast‐to‐myofibroblast differentiation in a dose‐dependent fashion, and breast cancer clusters recruit activated stromal cells and guide the sprouting of endothelial cells in a spatially resolved manner. The established platform not only provides strategies to fabricate ECM‐like interfaces for medical devices, but also offers the capability of spatially controlling cell organization for fundamental studies, and for high‐throughput screening of various biomolecules for stem cell differentiation and cancer therapeutics.     

加注过程中液氧的温升和液氧泵的变频调速技术

分析了用泵加注液氧的温升，给出了温升计算公式并举例做了计算。指出采用调速泵加注可以消除因节流引起的能量损耗，降低液氧的温升，最后介绍了用现代变频器实现加注泵调速的技术。     

Positive potential operation of a cathodic electrogenerated chemiluminescence immunosensor based on luminol and graphene for cancer biomarker detection

In this work, we report a cathodic electrogenerated chemiluminescence (ECL) of luminol at a positive potential (ca. 0.05 V vs Ag/AgCl) with a strong light emission on the graphene-modified glass carbon electrode. The resulted graphene-modified electrode offers an excellent platform for high-performance biosensing applications. On the basis of the cathodic ECL signal of luminol on the graphene-modified electrode, an ECL sandwich immunosensor for sensitive detection of cancer biomarkers at low potential was developed with a multiple signal amplification strategy from functionalized graphene and gold nanorods multilabeled with glucose oxidase (GOx) and secondary antibody (Ab(2)). The functionalized graphene improved the electron transfer on the electrode interface and was employed to attach the primary antibody (Ab(1)) due to it large surface area. The gold nanorods were not only used as carriers of secondary antibody (Ab(2)) and GOx but also catalyzed the ECL reaction of luminol, which further amplified the ECL signal of luminol in the presence of glucose and oxygen. The as-proposed low-potential ECL immunosensor exhibited high sensitivity and specificity on the detection of prostate protein antigen (PSA), a biomarker of prostate cancer that was used as a model. A linear relationship between ECL signals and the concentrations of PSA was obtained in the range from 10 pg mL(-1) to 8 ng mL(-1). The detection limit of PSA was 8 pg mL(-1) (signal-to-noise ratio of 3). Moreover, the as-proposed low-potential ECL immunosensor exhibited excellent stability and reproducibility. The graphene-based ECL immunosensor accurately detected PSA concentration in 10 human serum samples from patients demonstrated by excellent correlations with standard chemiluminescence immunoassay. The results suggest that the as-proposed graphene ECL immunosensor will be promising in the point-of-care diagnostics application of clinical screening of cancer biomarkers.     

Engineered Fibrillar Fibronectin Networks as Three‐Dimensional Tissue Scaffolds

Extracellular matrix (ECM) proteins, and most prominently, fibronectin (Fn), are routinely used in the form of adsorbed pre‐coatings in an attempt to create a cell‐supporting environment in both two‐ and three‐dimensional cell culture systems. However, these protein coatings are typically deposited in a form which is structurally and functionally distinct from the ECM‐constituting fibrillar protein networks naturally deposited by cells. Here, the cell‐free and scalable synthesis of freely suspended and mechanically robust three‐dimensional (3D) networks of fibrillar fibronectin (fFn) supported by tessellated polymer scaffolds is reported. Hydrodynamically induced Fn fibrillogenesis at the three‐phase contact line between air, an Fn solution, and a tessellated scaffold microstructure yields extended protein networks. Importantly, engineered fFn networks promote cell invasion and proliferation, enable in vitro expansion of primary cancer cells, and induce an epithelial‐to‐mesenchymal transition in cancer cells. Engineered fFn networks support the formation of multicellular cancer structures cells from plural effusions of cancer patients. With further work, engineered fFn networks can have a transformative impact on fundamental cell studies, precision medicine, pharmaceutical testing, and pre‐clinical diagnostics.     

低温胁迫对青椒膜脂代谢的影响

目的为了研究低温胁迫对青椒膜脂代谢的影响。方法以“晋黎”青椒为实验材料,测定10℃(对照)和4℃(低温胁迫)等不同贮藏温度下青椒相对电导率、丙二醛(MDA)、脯氨酸、磷脂酶D(PLD)、脂氧合酶(LOX)活性、脂肪酸组分的变化情况。结果在低温胁迫下,青椒的相对电导率升高,MDA积累,脯氨酸含量增加,PLD和LOX活性升高,亚油酸、亚麻酸减少,硬脂酸增加,脂肪酸不饱和指数降低。结论低温胁迫诱导青椒PLD和LOX活性上升,引起不饱和脂肪酸降解,饱和脂肪酸增加,膜流动性减弱,最终导致膜失去完整性,在这过程中脯氨酸含量明显升高。     

A Sequential Target‐Responsive Nanocarrier with Enhanced Tumor Penetration and Neighboring Effect In Vivo

Nanodrug‐based cancer therapy is impeded by poor penetration into deep tumor tissues mainly due to the overexpression of hyaluronic acid (HA) in the tumor extracellular matrix (ECM). Although modification of nanoparticles (NPs) with hyaluronidase (HAase) is a potent strategy, it remains challenging to get a uniform distribution of drug at the tumor site because of the internalization of NPs by the cells in the tumor and HA regeneration. Herein, an intelligent nanocarrier, which can release HAase in response to the acidic tumor microenvironment (pH 6.5) and perform a strong neighboring effect with size reduction to overcome the above two problems and accomplish drug deep tumor penetration in vivo, is reported. In this design, HAase is encapsulated on the surfaces of doxorubicin (DOX) preloaded ZnO‐DOX NPs using a charge convertible polymer PEG‐PAH‐DMMA (ZDHD). The polymer can release HAase to degrade HA in the tumor ECM (pH 6.5). ZnO‐DOX NPs can release DOX in lysosomes (pH 4.5) to induce cell apoptosis, and exert a neighboring effect with size reduction to infect neighboring cells. The hierarchical targeted release of HAase and drugs is demonstrated to enhance tumor penetration and decrease side effects in vivo. This work shows promise for further application of ZDHD NPs in cancer therapy.     

Characteristics of environmental factor for electrochemical migration on printed circuit board

This study investigates whether electrochemical migration (ECM) is affected by factors such as the printed circuit board (PCB) material, distance between the conductors, bias voltage, contamination and underfill process under water drop (WD), temperature and humidity bias (THB), and polarization tests. The resistance of ECM with polyimide PCB was greater than that with FR-4 (flame resistant-4) PCB. The ECM rate was increased by decreasing the distance between the conductors of opposite polarity and increasing the bias voltage. The cured underfill on PCB protected the ECM growth, while contamination with chlorine ions accelerated the ECM growth.     

Investigation of cryogenic level sensors for LN2 and LOX

Investigations of two different types of cryogenic level sensors (capacitance and High Temperature Superconductor (HTS) for level measurement of liquid nitrogen (LN₂) and liquid oxygen (LOX) are presented here. They were tested for an active length of 400 mm in LOX and LN₂. A discrete diode array level sensor was used as a primary standard for calibrating these sensors. Comparative studies on linearity, sensitivity and other parameters at the operating temperatures are presented.     

Detection of protein biomarkers using RNA aptamer microarrays and enzymatically amplified surface plasmon resonance imaging

A methodology for the detection of protein biomarkers at picomolar concentrations that utilizes surface plasmon resonance imaging (SPRI) measurements of RNA aptamer microarrays is developed. The adsorption of proteins onto the RNA microarray is detected by the formation of a surface aptamer-protein-antibody complex. The SPRI response signal is then amplified using a localized precipitation reaction catalyzed by the enzyme horseradish peroxidase that is conjugated to the antibody. This enzymatically amplified SPRI methodology is first characterized by the detection of human thrombin at a concentration of 500 fM; the appropriate thrombin aptamer for the sandwich assay is identified from a microarray of three potential thrombin aptamer candidates. The SPRI method is then used to detect the protein vascular endothelial growth factor (VEGF) at a biologically relevant concentration of 1 pM. VEGF is a signaling protein that has been used as a serum biomarker for rheumatoid arthritis, breast cancer, lung cancer, and colorectal cancer and is also associated with age-related macular degeneration.     

Significance of antibody orientation unraveled: well-oriented antibodies recorded high binding affinity

To investigate the effect of antibody orientation on its immunological activities, we developed a novel and versatile platform consisting of a well-defined phospholipid polymer surface on which staphylococcal protein A (SpA) was site-selectively immobilized. The application of a biocompatible phospholipid-based platform ensured minimal denaturation of immobilized antibodies, and the site-selective immobilization of SpA clarified the effect of antibody orientation on immunological activities. The phospholipid polymer platform was prepared on silicon substrates using the surface-initiated atom transfer radical polymerization (SI-ATRP) technique. An enzymatic reaction was performed for orientation-selective coupling of SpA molecules to the polymer brush surface. Orientation-controlled antibodies were achieved using enzymatic reactions, and these antibodies captured 1.8 ± 0.1 antigens on average, implying that at least 80% of immobilized antibodies reacted with two antigens. Theoretical multivalent binding analysis further revealed that orientation-controlled antibodies had antigen-antibody reaction equilibrium dissociation constants (K(d)) as low as 8.6 × 10(-10) mol/L, whereas randomly oriented and partially oriented antibodies showed K(d) values of 2.0 × 10(-7) and 1.2 × 10(-7) mol/L, respectively. Strict control of antibody orientation not only formed an approximately 100-fold stronger antigen-antibody complex than the controls but also sustained the native antibody K(d) (10(-10)-10(-9) mol/L). These findings support the significance of antibody orientation because controlling the orientation resulted in high reactivity and theoretical binding capacity.     

Artificial neural network‐based analysis of effective crack model in concrete fracture

Many non‐linear fracture models have been proposed by design codes and investigators to determine fracture parameters of cement‐based materials. To characterise failure of concrete structures, the effective crack model (ECM) needs two fracture parameters: the effective crack length a_e and the critical stress intensity factor . Nevertheless, ECM requires a closed‐loop testing system and the calculation of a_e needs considerable computational effort. For this reason, ECM is simulated with an artificial neural network (ANN) in this study. The main benefit of using an ANN approach is that the network is built directly on experimental data by using the self‐organizing capabilities of the ANN. The presented fracture model was developed by utilising 464 noisy test data taken from the literature, which were obtained via different test methods in different laboratories. The results of an ANN‐based ECM look viable and very promising.     

静电纺丝控释材料的最新研究进展

目的 综述静电纺丝的发展和原理,控释材料和控释体系,以及静电纺丝控释材料(Electrospinning controlled-release material,ECM)在药物缓释和抗菌方面的应用,旨在为ECM的相关研究提供理论参考和研究思路。方法 通过对国内外研究成果的分析和总结,介绍ECM通过环境pH调节、羧基修饰纳米纤维、光响应、纳米纤维膜厚度、纤维表面孔隙等因素进行控制释放的应用。结果 分析表明,ECM可以应用于药物缓释和抗菌方面,可以实现药物在特定条件下的响应和释放,让药物有合适的释放周期。此外,还可以对各类抗菌剂实现控释,达到长效杀菌、延长货架期的目的。结论 研究ECM(药物缓释用),能够实现药物的可控释放,保证药效的持久性,提升治疗效果。研究ECM(缓释抗菌用)可以获得更长效的抗菌效果,提高食品和药品的卫生安全性。ECM在药物缓释和抗菌方面具有很大的发展前景。