Cellular Uptake,Intracellular Trafficking and Biological Responses of Gold Nanoparticles

Promising application of gold nanoparticles (GNPs) in biomedical and environmental fields is increasing the likelihood of direct interaction with living systems. The knowledge about GNPs interacting with cells is quite limited and however, is necessary for risk prediction and evaluation of biological effects. Herein, we review recent advances in cellular effects of GNPs including cellular uptake, trafficking, subcellular distribution and cellular responses, and the relationship between physiochemical properties of GNPs and biological effects as well. To uncover these issues, it is quite instructive for safe and sustainable use of GNPs.     

Tuning the Cellular Uptake and Retention of Rhodamine Dyes by Molecular Engineering for High-Contrast Imaging of Cancer Cells

Probes allowing high-contrast discrimination of cancer cells and effective retention are powerful tools for the early diagnosis and treatment of cancer. However, conventional small-molecule probes often show limited performance in both aspects. Herein, we report an ingenious molecular engineering strategy for tuning the cellular uptake and retention of rhodamine dyes. Introduction of polar aminoethyl leads to the increased brightness and reduced cellular uptake of dyes, and this change can be reversed by amino acetylation. Moreover, these modifications allow cancer cells to take up more dyes than normal cells (16-fold) through active transport. Specifically, we further improve the signal contrast (56-fold) between cancer and normal cells by constructing activatable probes and confirm that the released fluorophore can remain in cancer cells with extended time, enabling long-term and specific tumor imaging.     

Engineering Hierarchical Recognition-Mediated Senolytics for Reliable Regulation of Cellular Senescence and Anti-Atherosclerosis Therapy

Precise regulation of vascular senescence represents a far-reaching strategy to combat age-related diseases. However, the high heterogeneity of senescence, alongside the lack of targeting and potent senolytics, makes it very challenging. Here we report a molecular design to tackle this challenge through multidimensional, hierarchical recognition of three hallmarks commonly shared among senescence, namely, aptamer-mediated recognition of a membrane marker for active cell targeting, a self-immolative linker responsive to lysosomal enzymes for switchable drug release, and a compound against antiapoptotic signaling for clearance. Such senolytic can target and trigger severe cell apoptosis in broad-spectrum senescent endothelial cells, and importantly, distinguish them from the quiescent state. Its potential for in vivo treatment of vascular diseases is successfully illustrated in a model of atherosclerosis, with effective suppression of the plaque progression yet negligible side effects.     

多肽与花粉钙调素的相互作用及对细胞功能的影响

研究了在Ca²⁺存在下,丹磺酰标记的花粉钙调素(D-pCaM)与合成的多肽相互作用的规律.研究结果表明,被研究的绝大多数多肽能与D-pCaM结合而形成复合物,使D-pCaM的荧光光谱发生变化.用荧光法测定了这些复合物的解离常数K_d,其中肽BP-13的Kd值为4.0nmol/L,是与pCaM结合能力最强的一个多肽.除证明了多肽的疏水性,预测二级结构形成倾向和链长对其与pCaM结合能力有影响外,还发现用D-丙氨酸取代肽链中的Gly或L-丙氨酸后,可改变肽对pCaM的亲和性,这为提高多肽与钙调素的亲和力提供了一条改进的途径.我们的研究还可以定性地说明不同来源CaM性质相似又有差异,反映了它们的高度保守性和变异性.同时还展示了所研究的多肽对细胞信息传导过程的影响,为研究CaM对细胞功能调节的作用机制和建立pCaM拮抗肽的活性筛选模型提供了思路.     

细胞吞噬表面电荷不同的硅纳米颗粒的研究

本文以HepG细胞、L-02细胞和MCF-7细胞为代表, 利用异硫氰酸罗丹明荧光SiNPs的荧光信号同步指示作用, 研究了细胞对表面带正电荷的氨基化SiO2荧光纳米颗粒(PSiNPs)和表面带负电荷的SiO2荧光纳米颗粒(NSiNPs)的吞噬情况, 并考察了SiNPs浓度、培育时间及培养基中的血清对细胞吞噬表面电荷不同的SiNPs颗粒的影响.     

血清对细胞摄取DNA四面体纳米结构行为的影响

研究了细胞培养基中的胎牛血清(FBS)对DNA四面体(Tetrahedral DNA nanostructure,TDNs)进入HeLa细胞的速度和内吞途径的影响.采用自组装技术得到荧光标记的TDNs结构,利用HPLC技术分离得到纯度>95%的TDNs单体,分别采用流式细胞术和共聚焦显微成像等技术比较了在有无血清的情况下,细胞摄取量随时间的变化以及FBS对TDNs摄取途径的影响.实验结果表明,TDNs在培养基和细胞裂解液环境中可以稳定存在12 h以上,培养基中的FBS能够提高HeLa细胞对四面体的摄取量, 但并未改变TDNs进入HeLa细胞的内吞途径.本研究揭示了环境中蛋白质等生物分子对于DNA四面体结构与细胞界面相互作用的影响,为基于DNA纳米材料的细胞学纳米载体的设计和优化提供了新思路.     

Generation of a Hydrophobic Protrusion on Nanoparticles to Improve the Membrane-Anchoring Ability and Cellular Internalization

Controlling the nanoparticle-cell membrane interaction to achieve easy and fast membrane anchoring and cellular internalization is of great importance in a variety of biomedical applications. Here we report a simple and versatile strategy to maneuver the nanoparticle-cell membrane interaction by creating a tunable hydrophobic protrusion on Janus particles through swelling-induced symmetry breaking. When the Janus particle contacts cell membrane, the protrusion will induce membrane wrapping, leading the particles to docking to the membrane, followed by drawing the whole particles into the cell. The efficiencies of both membrane anchoring and cellular internalization can be promoted by optimizing the size of the protrusion. In vitro, the Janus particles can quickly anchor to the cell membrane in 1 h and be internalized within 24 h, regardless of the types of cells involved. In vivo, the Janus particles can effectively anchor to the brain and skin tissues to provide a high retention in these tissues after intracerebroventricular, intrahippocampal, or subcutaneous injection. This strategy involving the creation of a hydrophobic protrusion on Janus particles to tune the cell-membrane interaction holds great potential in nanoparticle-based biomedical applications.     

Cellular Uptake of a Polypyridyl Ruthenium Complex Revealed Using a Fluorescent Rhodamine‐modified Ruthenium Complex

A fluorescent polypyridyl ruthenium complex was successfully prepared using an amide bond linkage to link two rhodamine moieties through bipyridine groups. Although photo‐induced electron transfer (PET) quenched the fluorescent intensity, the quantum yield of the rhodamine‐modified Ru(II) complex was 0.17 in water, sufficient for observing the fluorophore behaviour in biological systems. The rhodaminemodified Ru(II) complex was found to inhibit the bacterial growth of E. coli. In vitro fluorescence images of human hepatoma cells (SK‐Hep1) showed that a fluorescent polypyridyl ruthenium complex not only supported the above observation but also preferably accumulated in the cytoplasmic region inside the cell. These observations suggest that in addition to strong Ru–DNA interactions, Ru‐protein interactions in the cytoplasmic regions are strong and are therefore important to the development of metallopharmaceuticals.     

微流控芯片中细胞动态胞吞二氧化硅纳米颗粒的研究

研究了用微流控芯片在体外模拟人体血液流动状态下细胞胞吞二氧化硅纳米粒子的方法和特性. 通过调节储液池的液面差, 使细胞从微通道入口流入并在通道内沉积贴壁生长. 将含有贴壁细胞的微流控芯片放入37 ℃/体积分数5%CO₂的培养箱中, 使细胞培养液连续流过贴壁细胞. 培养24 h后, 在流动的培养液中加入作为荧光标记物的500 nm 粒径的掺杂有异硫氰酸荧光素(FITC)的二氧化硅微球(MSN), 继续培养6 h后, 用荧光显微镜测定细胞胞吞二氧化硅纳米粒子后的荧光强度, 考察了不同流速下细胞对二氧化硅微球摄入量的影响. 结果表明, 在动态条件下, 细胞对二氧化硅微球的吞噬量明显下降, 当流速从0.022 mm/s 增加至0.74 mm/s时, 吞噬量从静态测得值的74.7%下降至7.1%.     

An efficient synthesis of 5-aminolaevulinic acid (ALA)-containing peptides for use in photodynamic therapy

An efficient and cost-effective procedure has been devised for the preparation of urethane-protected 5-aminolaevulinic acid (5-ALA) dipeptide ester derivatives which avoids problems associated with the instability of 5-ALA under basic conditions. The procedure is also applicable to the direct synthesis of N-(α)-acetyl amino acid-ALA dipeptides in high enantiomeric purity as potential novel prodrugs for photodynamic therapy (PDT).     

The Metabolostasis Network and the Cellular Depository of Aggregation-Prone Metabolites

The vital role of metabolites across all branches of life and their involvement in various disorders have been investigated for decades. Many metabolites are poorly soluble in water or in physiological buffers and tend to form supramolecular aggregates. On the other hand, in the cell, they should be preserved in a pool and be readily available for the execution of biochemical functions. We thus propose that a quality-control network, termed “metabolostasis”, has evolved to regulate the storage and retrieval of aggregation-prone metabolites. Such a system should control metabolite concentration, subcellular localization, supramolecular arrangement, and interaction in dynamic environments, thus enabling normal cellular physiology, healthy development, and preventing disease onset. The paradigm-shifting concept of metabolostasis calls for a reevaluation of the traditional view of metabolite storage and dynamics in physiology and pathology and proposes unprecedented directions for therapeutic targets under conditions where metabolostasis is imbalanced.     

Giant Water Uptake Enabled Ultrahigh Proton Conductivity of Graphdiyne Oxide

Proton conductors have attracted great attention in various fields, especially in energy production. Here, we find that graphdiyne oxide (GDYO), derived from graphdiyne (GDY), features the highest proton conductivity of 0.54 S cm⁻¹ (100 % RH, 348 K) among the oxidized carbon allotropes reported so far. The sp- and sp²-co-hybridized carbon skeleton of GDY enables GDYO with the giant water uptake, which is 2.4 times larger than that of graphene oxide (GO), resulting in ultrahigh proton conductivity by increasing the proton concentration and proton conduction pathways. This ultrahigh proton conductivity of GDYO is further proved in a methanol fuel cell by using GDYO membrane as proton exchange membrane. The GDYO membrane enables the cell with higher open circuit voltage, larger power density and lower methanol permeability, compared with commercial Nafion 117. Moreover, the GDYO membrane bears high ion exchange capacity, good acidic stability and low swelling ratio.     

新型杀菌剂氟吗啉在黄瓜植株体内的吸收传导行为

利用生物测定技术和高效液相色谱法研究了氟吗啉在黄瓜植株体内的吸收、传导和分布行为及其机制. 结果表明, 氟吗啉能被黄瓜植株被动吸收, 并通过木质部在体内传导和分布.     

Investigation of Crawfish (Procambrus Clarkii) Shells for Uptake and Removal of Lead in Water

The use of ground crawfish (Procambrus clarkii) shells for the uptake and removal of Pb ions in water was investigated. Using inductively coupled plasma-optical emission spectrometry, the samples were analyzed for various concentrations of Pb at three different volumes of 40 mL, 500 mL, and 3000 mL. The results showed that with an increase in volume of water, the capacity to remove Pb by the crawfish exoskeleton shell powder decreased. However, the Pb absorption by the same amount of shell powder in all the phases was good in terms of efficiency. The phase III study (3000 mL of water) showed that 0.5 g of crawfish absorbed the maximum amount of Pb. Moreover, both raw and boiled crawfish shells have almost the same capacity to uptake Pb from water.     

Stimuli Induced Uptake of Protein-Like Peptide Brush Polymers

Recently, we presented a strategy for packaging peptides as side-chains in high-density brush polymers. For this globular protein-like polymer (PLP) formulation, therapeutic peptides were shown to resist proteolytic degradation, enter cells efficiently and maintain biological function. In this paper, we establish the role charge plays in dictating the cellular uptake of these peptide formulations, finding that peptides with a net positive charge will enter cells when polymerized, while those formed from anionic or neutral peptides remain outside of cells. Given these findings, we explored whether cellular uptake could be selectively induced by a stimulus. In our design, a cationic peptide is appended to a sequence of charge-neutralizing anionic amino acids through stimuli-responsive cleavable linkers. As a proof-of-concept study, we tested this strategy with two different classes of stimuli, exogenous UV light and an enzyme (a matrix metalloproteinase) associated with the inflammatory response. The key finding is that these materials enter cells only when acted upon by the stimulus. This approach makes it possible to achieve delivery of the polymers, therapeutic peptides or an appended cargo into cells in response to an appropriate stimulus.     

铅对大鼠海马谷氨酸递质体外摄取和释放的影响

为了探讨铅损害学习记忆功能的神经生物学机制，用海马突触小体和脑片分别观察了铅在体外对谷氨酸递质摄取和释放的影响。结果显示，3．1－50.0μmol／L铅使海马突触小体3H-DL-谷氨酸摄取量增加70．4％－193．2％，使脑片无钙状态下的自发性释放量增加23．2％－66．2％，并均有剂量-效应关系。但是在含钙介质中，当铅染毒剂量从1．0μmol/L增加为50．0μmol/L时，3H－DL-谷氨酸的自发性释放量减少22．6％－55．3％。而高钾去极化释放量增加89．3％－332．1％，而且也均存在剂量-效应关系。提示铅不仅能促进谷氨酸递质的灭活，而且还干扰它的释放过程。这可能会影响该递质的突触传递过程及其兴奋性作用，使LTP现象减弱或不能产生。     

Facile Preparation and Cellular Imaging of Photoluminescent Carbogenic Nanoparticles Derived from Defoliations

1 Introduction In the past two decades,photoluminescent semiconductor quantum dots(QDs) have received intensive attention for a variety of promising properties and applications[1,2],especially for their potential application in cellular imaging[3-5].QDs with high quantum yield have been prepared based on cadmium(zinc) selenide(sulfide) and related core-shell composites[6-8].However,the release of Cd2+,S2-and Se2-ions inevitably causes serious health and environmental concerns.Therefore,many efforts have been devoted to developing benign alternatives with enhanced photoluminescence,such as silicon nanoparticles and nanowires[9,10].     

14C-寡糖在西瓜幼苗植株体内吸收传导和分布

应用同位素示踪技术研究了14C-寡糖在西瓜幼苗植株体内的吸收、传导和分布行为.自显影结果显示,寡糖通过处理叶部或根部后能够被西瓜幼苗植株快速吸收,在叶片中的传导表现为从叶缘向叶片中心分布的趋势.将叶部处理8h和根部处理24h后,14C-寡糖即可以传导和分布到西瓜幼苗的整个植株体内,证明14C-寡糖在西瓜幼苗植株体内具有较强的扩散和向基或向顶传导特征.结果表明,处理叶部4～120h时,根系、茎与未被直接处理的叶片等其它部位的放射性比活度分别由0.18×105和23.08×105Bq/kg变化为0.32×105和3.02×105Bq/kg,总体上表现出向基传导和分布的态势.处理根部4～120h时,西瓜幼苗植株根系、茎部、子叶和真叶中放射性比活度分别由22.23×105,2.23×105,8.33×105和12.78×105Bq/kg变化为431.11×105,42.23×105,65.57×105和78.89×105Bq/kg,表现出14C-寡糖在西瓜幼苗植株体内向顶传导作用和在地上部的积累态势很强.