Micromotor-Assisted Keratinocytes Migration in a Floating Paper Chip

In vitro epidermis models are important to evaluate and study disease progression and possible dermal drug delivery. An in vitro epidermis model using floating paper chips as a scaffold for proliferation and differentiation of primary human keratinocytes is reported. The formation of the four main layers of the epidermis (i.e., basal, spinosum, granulose, and cornified layers) is confirmed. The development of a cornified layer and the tight junction formation are evaluated as well as the alterations of organelles during the differentiation process. Further, this in vitro model is used to assess keratinocyte migration. Finally, magnetic micromotors are assembled, and their ability to aid cell migration on paper chips is confirmed when a static magnetic field is present. Taken together, this attempt to combine bottom-up synthetic biology with dermatology offers interesting opportunities for studying skin disease pathologies and evaluate possible treatments.     

Construction of Exosome SORL1 Detection Platform Based on 3D Porous Microfluidic Chip and its Application in Early Diagnosis of Colorectal Cancer

Exosomes are promising new biomarkers for colorectal cancer (CRC) diagnosis, due to their rich biological fingerprints and high level of stability. However, the accurate detection of exosomes with specific surface receptors is limited to clinical application. Herein, an exosome enrichment platform on a 3D porous sponge microfluidic chip is constructed and the exosome capture efficiency of this chip is ≈90%. Also, deep mass spectrometry analysis followed by multi-level expression screenings revealed a CRC-specific exosome membrane protein (SORL1). A method of SORL1 detection by specific quantum dot labeling is further designed and the ensemble classification system is established by extracting features from 64-patched fluorescence images. Importantly, the area under the curve (AUC) using this system is 0.99, which is significantly higher (p < 0.001) than that using a conventional biomarker (carcinoembryonic antigen (CEA), AUC of 0.71). The above system showed similar diagnostic performance, dealing with early-stage CRC, young CRC, and CEA-negative CRC patients.     

Effect of Hydroxyapatite Nanorods on the Fate of Human Adipose‐Derived Stem Cells Assessed In Situ at the Single Cell Level with a High‐Throughput,Real‐Time Microfluidic Chip

The fate of stem cells at the single cell level with limited communication with other cells is still unknown due to the lack of an efficient tool for highly accurate molecular detection. Moreover, the conditional sensitivity of biological experiments requires a sufficient number of parallel experiments to support a conclusion. In this work, a microfluidic single cell chip is designed for use with a protein chip to investigate the effect of hydroxyapatite (HAp) on the osteogenic differentiation of human adipose‐derived stem cells (hADSCs) in situ at the single cell level. By successfully detecting secretory proteins in situ, it is found that the HAp nanorods enhance osteogenic differentiation at the single cell level. In the chip, the single cell seeding approach confirms the osteogenic differentiation of the hADSCs, which endocytoses HAp, by reducing the influence of the factors secreted by neighboring differentiating cells. Most importantly, more than 7000 microchambers provide a sufficient number of parallel experiments for statistical analysis, which ensure a high level of repeatability of the HAp nanorod‐induced osteogenic differentiation. The microfluidic chip comprising single cell culture microchambers with in situ detection capability is a promising tool for research on cell behavior or cell fate at the single cell level.     

基于微流控的海藻酸钙空心纤维的制备及其在细胞培养中的应用

海藻酸钙水凝胶空心纤维在药物传递、组织工程等领域具有潜在的应用价值。但传统的纤维制备方法,如静电纺丝或模具法等,很难或无法制备海藻酸钙空心纤维。本研究首先采用自制的两相微流控装置,连续制备出形貌均一稳定的海藻酸钙空心纤维,并通过显微镜和扫描电子显微镜(SEM)对其空心结构进行了表征。然后考察了装置中内相毛细管尖端管径、内外相流体流速比以及氯化钙浓度对空心纤维内外径尺寸和厚度的影响,结果表明,空心纤维的尺寸在一定范围内可以进行调控。最后将这种空心纤维应用于封装和培养L929成纤维细胞,结果表明,成纤维细胞存活率较高,并且有沿着空心纤维内壁成直线生长的趋势。这种方法为纤维状细胞的培养提供了一种思路。     

陶瓷制品口缘和器身中金属元素迁移的研究

目的研究陶瓷制品口缘和器身中多种金属元素的迁移风险,并考察合规判定规则。方法采用体积分数为4%乙酸模拟物对41种杯类陶瓷口缘和器身进行3次迁移实验,用电感耦合等离子体质谱法对试液中的18种金属元素进行检测。结果陶瓷制品口缘和器身的金属元素迁移量平均值随迁移次数递减;铝(Al)、钴(Co)、锌(Zn)、铅(Pb)的最大迁移量超过讨论限量10%的样品数,明显高于其他金属元素的样品数,且同样特征的样品中口缘的样品数高于器身的样品数。结论陶瓷制品具有较高的Al、Co、Zn、Pb迁移风险,而且口缘比器身的迁移风险更高。建议金属元素迁移量以第1次迁移实验结果进行合规判定。     

用于食品包装材料成分迁移数学模型的研究进展

目的综述目前食品用包装材料中成分迁移的数学模型及相关研究进展,为迁移数学模型的推广和进一步开发提供有价值的参考。方法分析影响食品包装材料中化学成分向食品迁移的因素,介绍几种应用较广的迁移模拟软件,论述不同类型迁移数学模型的适用性及优缺点,并说明其在食品包装材料法规标准及化学成分暴露风险评估中的应用。结果许多学者的研究都证明迁移数学模型可部分代替迁移实验,产生的结果可靠且具有代表性。结论迁移模型是一种预测化学物质从食品包装材料迁移到食品中的有效工具,虽可在一定程度上代替迁移实验从而节省成本,但迁移模型的应用还存在许多问题亟需解决。     

果蔬用泡沫箱中挥发性有机物的迁移特性

目的 研究果蔬用聚苯乙烯泡沫箱中挥发性有机物的迁移情况,对食物接触泡沫箱后的安全性进行评估.方法 采集不同来源的泡沫箱,先用乙酸(体积分数为4％)和乙醇(体积分数为10％)对其进行模拟液迁移实验,然后选取迁移量较高的挥发性有机物进行实物迁移实验,检测挥发性有机物的迁移量.结果 模拟液的迁移实验中检出间二甲苯、对二甲苯、邻二甲苯、苯乙烯、乙苯和1,3-丁二烯均有不同程度的迁移,并且体积分数为10％的乙醇作为迁移液时迁移值较高,苯乙烯在体积分数为10％的乙醇中迁移量最高;实物迁移实验中邻二甲苯在橙子中未检出,苯乙烯在橙子中的迁移量随着温度的升高,贮藏时间越长,迁移量越高.菜心检出了邻二甲苯,并且迁移量同样随着温度和时间的增加而呈现上升趋势,樱桃番茄中未检出挥发性有机物的迁移.结论 泡沫箱中苯乙烯、邻二甲苯在模拟液中的迁移量较高,并且在较高温度、较长时间接触橙子和菜心后可能会大量迁移,对人体健康产生风险.     

铬革渣在产蛋鸡体内的分布及其迁移规律的研究

文章分析了动物体内铬的来源及其危害,并对饲料以及用普通饲料饲养一年的产蛋鸡的鸡蛋、鸡肝、鸡肺中的铬进行了测定。测定数据表明,铬主要累积于鸡肝、鸡肺中,含量较高,接近或超过临界值,对人们的正常饮食有潜在危害。本研究不仅具有理论基础,并且对人们的日常饮食具有指导意义。     

Screening for Chemicals in Paper and Board Packaging for Food Use: Chemometric Approach and Estimation of Migration

An analytical survey of 20 paper and board (P&B) materials intended for food use was carried out with the aim to identify chemicals with a potential to migrate into foods. Representative materials covering a range of uses (primary and secondary packaging and article for take away foods) were obtained from distributors. A screening approach was applied by means of solvent extraction with subsequent analysis by gas chromatography/mass spectrometry. A large number of analytes were detected, and a chemometric approach was used to explore the data. Principal component analysis was used to identify and select some compounds as markers for sample classification. In the corrugated and printed packaging, it is worth emphasizing the presence of residual solvents, probably coming from printing inks, as well as hydrocarbons and aromatic compounds, mainly toluene and plasticizers linked also to the recycled pulp content such as diisobutyl phthalate or diisopropylnaphthalenes, whereas in the plastic‐laminated samples, triacetin was identified as the prevailing compound. A literature search for safety data or legislative restrictions of the identified substances was performed. Additionally, the semi‐quantification of the compounds in the packaging allowed a worst case estimation of food contamination by means of the infinite total migration model; occasionally, migration estimations overcame the specific migration limits. The chosen analytical methods coupled with a chemometric approach proved to be an effective way to describe the data; it may be concluded that only the simultaneous consideration of several chemicals with a multivariate approach allowed the investigated packaging materials to be distinguished. Copyright © 2014 John Wiley & Sons, Ltd.     

Construction of CpG Delivery Nanoplatforms by Functionalized MoS2 Nanosheets for Boosting Antitumor Immunity in Head and Neck Squamous Cell Carcinoma

Despite the promising achievements of immune checkpoint blockade (ICB) therapy for tumor treatment, its therapeutic effect against solid tumors is limited due to the suppressed tumor immune microenvironment (TIME). Herein, a series of polyethyleneimine (Mw = 0.8k, PEI_0.8k)-covered MoS₂ nanosheets with different sizes and charge densities are synthesized, and the CpG, a toll-like receptor-9 agonist, is enveloped to construct nanoplatforms for the treatment of head and neck squamous cell carcinoma (HNSCC). It is proved that functionalized nanosheets with medium size display similar CpG loading capacity regardless of low or high PEI_0.8k coverage owing to the flexibility and crimpability of 2D backbone. CpG-loaded nanosheets with medium size and low charge density (CpG@M_M-P_L) could promote the maturation, antigen-presenting capacity, and proinflammatory cytokines generation of bone marrow-derived dendritic cells (DCs). Further analysis reveals that CpG@M_M-P_L effectively boosts the TIME of HNSCC in vivo including DC maturation and cytotoxic T lymphocyte infiltration. Most importantly, the combination of CpG@M_M-P_L and ICB agents anti-programmed death 1 hugely improves the tumor therapeutic effect, inspiring more attempts for cancer immunotherapy. In addition, this work uncovers a pivotal feature of the 2D sheet-like materials in nanomedicine development, which should be considered for the design of future nanosheet-based therapeutic nanoplatforms.     

Ion‐Migration Inhibition by the Cation–π Interaction in Perovskite Materials for Efficient and Stable Perovskite Solar Cells

Migration of ions can lead to photoinduced phase separation, degradation, and current–voltage hysteresis in perovskite solar cells (PSCs), and has become a serious drawback for the organic–inorganic hybrid perovskite materials (OIPs). Here, the inhibition of ion migration is realized by the supramolecular cation–π interaction between aromatic rubrene and organic cations in OIPs. The energy of the cation–π interaction between rubrene and perovskite is found to be as strong as 1.5 eV, which is enough to immobilize the organic cations in OIPs; this will thus will lead to the obvious reduction of defects in perovskite films and outstanding stability in devices. By employing the cation‐immobilized OIPs to fabricate perovskite solar cells (PSCs), a champion efficiency of 20.86% and certified efficiency of 20.80% with negligible hysteresis are acquired. In addition, the long‐term stability of cation‐immobilized PSCs is improved definitely (98% of the initial efficiency after 720 h operation), which is assigned to the inhibition of ionic diffusions in cation‐immobilized OIPs. This cation–π interaction between cations and the supramolecular π system enhances the stability and the performance of PSCs efficiently and would be a potential universal approach to get the more stable perovskite devices.