纳米材料在生物医学检测中的应用

纳米技术的兴起,对生物医学领域的变革产生了深远的影响。纳米材料是纳米技术发展的重要基础,它具有许多传统材料所不具备的独特的理化性质,因此在生物医学、传感器等重要技术领域有着广泛的应用前景。对几类常见的纳米材料包括纳米金、量子点、磁性纳米粒子、碳纳米管和硅纳米线在蛋白质、DNA、金属离子以及生物相关分子检测方面的应用进行综述。     

综述——纳米材料在组织工程中的应用：磁性纳米材料在组织工程研究中的应用

磁性纳米材料因其独特的理化性质在组织工程研究中被广泛地应用．本文主要从磁性纳米材料的表面化学活性、磁学性质以及生物应用磁性纳米材料的主要合成方法等几方面,综述了近年来利用磁性纳米材料设计组织工程支架材料的相关研究进展,包括纳米条件下的生长因子及相关基因的包裹和释放、机械力学刺激、干细胞追踪以及细胞图案化．     

纳米磁性液体的性质、制备方法及其在生物医药中的应用进展

纳米磁性液体是一种新型的功能材料,其在蛋白质、核酸分离纯化、微生物检测、基因治疗等方面有着广泛的应用前景。磁性纳米材料现已广泛应用于我们生产生活中的各个领域,其应用可谓包罗万象,它在旋转轴动态密封、扬声器制作、阻尼器件制造、选矿分离、治疗癌症、精密研磨和抛光等方面具有极大的价值。本文对纳米磁性液体的性质和制备进行了简介,并详细介绍了其功能及其在蛋白质、核酸分离纯化和在细胞分离、微生物检测、基因治疗方面的应用。并对其发展前景进行了展望。     

综述与专论: 纳米酶在分析化学中的应用研究：从体外检测到活体分析

纳米酶是指具有类酶催化活性的纳米材料．近年来,纳米酶研究引起了人们的极大兴趣．纳米酶已被广泛应用于诸如生物传感、生物成像、疾病治疗和环境保护等众多领域．在本综述中,我们将着重讨论纳米酶在分析化学领域的研究进展．首先将讨论纳米酶在体外检测的应用,将包括生物活性小分子、核酸、蛋白质类生物标志物、细胞等的检测．其后将讨论纳米酶在活体分析的应用,将包括监测活脑、肿瘤组织等的生物活性小分子、药物的药效、药物与纳米酶的代谢等．最后,我们将讨论纳米酶应用于分析化学时面临的挑战和未来研究前景．     

纳米生物学与纳米酶学：新兴交叉科学

纳米科学技术是20世纪80年代末期诞生并蓬勃发展的新兴科学技术,以多学科交叉融合为特色,为物理、化学、材料和生命科学等提供新的技术手段和研究视角.纳米材料的结构及表面物理化学性质直接决定了其与生物分子、细胞、组织、器官及个体的相互作用方式,并由此产生独特的生物效应——纳米生物效应.纳米生物学是从个体、细胞及分子水平深入研究纳米生物效应、阐明其精确机制的交叉科学,现已成为极具挑战性的热点前沿领域.中国科学家在纳米生物学领域已取得一系列令国际同行瞩目的重要进展,其中纳米酶(nanozyme)的开发及应用研究是极具代表性的原创发现之一.     

果树中糖类代谢和调控研究

糖是生物体内主要的碳源,是光合作用的主要产物,可为生物体提供能量,在植物的生长发育过程中起重要作用。本文综述了近年来关于糖类与果树生长发育及品质形成方面的相关研究进展,重点介绍了糖类运输、积累与基因表达、糖信号传导和糖类调控网络等方面的研究进展,并对今后利用分子生物学手段进行果实品质改良等方面的研究方向进行了展望。     

纳米材料在蛋白质分析中的应用

纳米材料因具有易与蛋白质结合而不影响其生化性质,可用于多种中间体的合成,可与酶、抗体结合而提高其性能等独特的优势而在蛋白质分析中得到了广泛的应用,尤其是与生物技术结合后,对纳米材料在蛋白质分离、富集和检测等方面的作用的研究已成为当前的热点。本文综述了纳米金、石墨烯、碳纳米管和碳纳米球在蛋白质分析中的应用,并对其未来的发展前景进行了展望。     

细胞对纳米材料的胞吞及其胞内定位相关机制的研究进展

纳米材料具有独特的理化性质,其在纳米生物医药技术中得到广泛的研究,有着良好的应用前景。纳米材料的尺寸分布在纳米级。使其入胞途径和转运方式与一般尺寸的物质略有不同。细胞可通过网格蛋白介导胞吞、陷窝小泡介导胞吞、吞噬作用和巨胞饮等胞吞方式摄取纳米颗粒。吞噬的方式及后续的转运和定位受细胞的类型、状态,以及纳米颗粒的理化性质如元素组成、尺寸、形状、电荷、表面修饰等多种因素共同影响。     

生物基分子介导纳米金属材料的制备及其应用

纳米金属材料具有纳米晶强化效应、光吸收率大、较高的表面能和单磁畴性能等优点,因其在医药、化学催化、抗菌抑毒等方面发挥着越来越重要的作用而受到人们广泛关注。近年来,随着全球石化资源消耗与日俱增,环境污染加剧,基于可再生资源的生物基分子介导纳米材料的制备研究方兴未艾。生物基分子是指直接或间接来源于生物质的小分子或大分子物质,它们多数具有生物相容性好、低毒、可降解、来源广泛、价格低廉等优点。且由于生物基分子多数具有独特的理化性质,如具有生理活性的旋光性、酸碱两性、亲水亲油性以及易与金属离子络合等,其介导合成的纳米材料还兼具其独特功能性,比如消炎、抗癌、抗氧化、抗病毒以及降血糖血脂等,进一步拓宽了纳米金属材料的应用领域。文中对近年来基于生物基分子介导纳米金属材料的制备及应用进行全面综述,为开展相关研究提供参考。     

糖核苷酸类化合物的合成与在生物学研究中的应用

糖基化是指在酶的作用下,蛋白质、脂质或小分子等连上糖类化合物的过程.它在生物体内广泛存在并有十分重要的生物学意艾.它是通过糖基转移酶催化完成的,其中糖核苷酸是糖基化过程中糖的供体.本文简要叙述了糖核苷酸类化合物的有机合成和生化合成的方法以及该类化合物在抗生素糖基化途径研究、糖基转移酶的生物化学研究和化学生物学机理研究中的应用.     

Glyconanoparticles: types, synthesis and applications in glycoscience, biomedicine and material science

Nanoparticles are the subject of numerous papers and reports and are full of promises for electronic, optical, magnetic and biomedical applications. Although metallic nanoparticles have been functionalized with peptides, proteins and DNA during the last 20 years, carbohydrates have not been used with this purpose until 2001. Since the first synthesis of gold nanoparticles functionalized with carbohydrates (glyconanoparticles) was reported, the number of published articles has considerably increased. This article reviews progress in the development of nanoparticles functionalized with biological relevant oligosaccharides. The glyconanoparticles constitute a good bio-mimetic model of carbohydrate presentation at the cell surface, and maybe, excellent tools for Glycobiology, Biomedicine and Material Science investigations.     

High Sensitive Detection of Carbohydrate Binding Proteins in an ELISA-Solid Phase Assay Based on Multivalent Glyconanoparticles

Improved detection of anti-carbohydrate antibodies is a need in clinical identification of biomarkers for cancer cells or pathogens. Here, we report a new ELISA approach for the detection of specific immunoglobulins (IgGs) against carbohydrates. Two nanometer gold glyconanoparticles bearing oligosaccharide epitopes of HIV or Streptococcus pneumoniae were used as antigens to coat ELISA-plates. A ~3,000-fold improved detection of specific IgGs in mice immunized against S. pneumoniae respect to the well known BSA-glycoconjugate ELISA was achieved. Moreover, these multivalent glyconanoparticles have been employed in solid phase assays to detect the carbohydrate-dependent binding of human dendritic cells and the lectin DC-SIGN. Multivalent glyconanoparticles in ELISA provide a versatile, easy and highly sensitive method to detect and quantify the binding of glycan to proteins and to facilitate the identification of biomarkers.     

Magnetic glyconanoparticles as a versatile platform for selective immunolabeling and imaging of cells

A versatile nanoplatform based on magnetic glyconanoparticles (glyco-ferrites) to attach well-oriented antibodies is described. An efficient ligand exchange process has been used to prepare water-soluble 6-nm-sized core-shell Fe(3)O(4)@Au nanoparticles bearing amphiphilic carbohydrates and aliphatic ethylene glycol chains ended in a carboxyl group. The covalent immobilization through the carboxyl group of an Fc receptor (protein G) enables successful well-oriented capture of immunoglobulins G onto the magnetic glyconanoparticle. A thorough characterization of structure and biofunctionality of the constructs is carried out by different techniques. The selective immunolabeling of cells by the antibody-magnetic glyconanoparticle conjugates is demonstrated by magnetic resonance imaging (MRI), as well as by fluorescence techniques.     

Synthesis and characterization of gold glyconanoparticles functionalized with sugars of sweet Sorghum syrup

Gold glyconanoparticles were synthesized by a simple, rapid, and eco-friendly method by using sweet Sorghum syrup for application in biomedicine and biotechnology. The nanostructures of the prepared gold nanoparticles were confirmed by using UV-visible absorbance, TEM, SAED, FTIR, EDAX, XRD, and photoluminescence analyses. The formation of gold nanoparticles at both room and boiling temperatures and kinetics of the reaction were monitored by UV-visible spectroscopy and TEM studies. TEM analysis revealed that the obtained nanoparticles were mono-dispersed and spherical in shape with an average particle size of 7 nm. The size of the nanoparticles was influenced by the concentration of Sorghum syrup. The presence of elemental gold was confirmed by EDAX analysis. Based on the FTIR analysis, it was observed that the sugars present in the Sorghum syrup possibly acts as capping agents. The zeta potential analysis revealed that the glyconanoparticles were negatively charged with a potential of -25 mV. The XRD and SAED patterns also suggest that the nanoparticles were crystalline in nature and these particles were found to exhibit visible photoluminescence. Fructose and glucose present in sweet Sorghum syrup were demonstrated as responsible sugars for the reduction of gold ions, and sucrose stabilized the formed nanoparticles. The proposed mechanism for the formation and stabilization of gold glyconanoparticles is based on the phenomenon of "macromolecular crowding." This is the first report on the use of sweet Sorghum syrup for the green synthesis of gold glyconanoparticles at both room and boiling temperatures.     

Silver glyconanoparticles functionalized with sugars of sweet sorghum syrup as an antimicrobial agent

Bio-directed synthesis of metal nanoparticles is gaining importance due to their biocompatibility, low toxicity and eco-friendly nature. We used sweet sorghum syrup for a facile and cost-effective green synthesis of silver glyconanoparticles. Silver nanoparticles were formed due to reduction of silver ions when silver nitrate solution was treated with sorghum syrup solutions of different pH values. The nanoparticles were characterized by UV–vis, TEM (transmission electron microscopy), DLS (dynamic light scattering), EDAX (energy dispersive X-ray spectroscopy), FT-IR (fourier transform infrared spectroscopy) and XRD (X-ray diffraction spectroscopy). The silver glyconanoparticles exhibited a characteristic surface plasmon resonance around 385 nm. At pH 8.5, the nanoparticles were mono-dispersed and spherical in shape with average particle size of 11.2 nm. The XRD and SAED studies suggested that the nanoparticles were crystalline in nature. EDAX analysis showed the presence of elemental silver signal in the synthesized glyconanoparticles. FT-IR analysis revealed that glucose, fructose and sucrose present in sorghum syrup acted as capping ligands. Silver glyconanoparticles prepared at pH 8.5 had a zeta potential of ?28.9 mV and were anionic charged. They exhibited strong antimicrobial activity against Gram-positive, Gram-negative and different Candida species at MIC values ranging between 2 and 32 μg ml^?1. This is first report on sweet sorghum syrup sugars-derived silver glyconanoparticles with antimicrobial property.     

Glycosylated polyacrylate nanoparticles by emulsion polymerization

A selection of glycosylated polyacrylate nanoparticles has been prepared by radical-initiated emulsion polymerization in aqueous media. Using ethyl acrylate as a co-monomer, carbohydrate acrylates were incorporated into the poly(ethyl acrylate) framework to give stable emulsions of glyconanoparticles with an average particle size of around 40 nm. Using this technique a variety of glyconanoparticles were prepared from 3-O-acryloyl-1,2:5,6-di-O-isopropylidene-alpha-D-glucofuranose, 1-O-acryloyl-2,3:5,6-di-O-isopropylidene-alpha-D-mannofuranose, 6-O-acryloyl-1,2:3,4-di-O-isopropylidene-alpha-D-galactopyranose, 2-N-acryloyl-1,3,4,6-tetra-O-acetyl-beta-D-glucosamine, 5-O-acryloyl-2,3-isopropylidene-1-methoxy-beta-D-ribofuranose and 4-N-acetyl-5'-O-acryloyl-2',3'-O-isopropylidene cytidine. Scanning electron microscopy, dynamic light scattering and proton NMR analysis of the emulsions indicated essentially 100% incorporation of the carbohydrate acrylate monomer into the polymer with the exception of O-benzyl- and O-benzoyl-protected carbohydrate acrylates, which gave incomplete incorporation. Formation of larger glyconanoparticles of ~80nm with (unprotected) 3-O-acryloyl-D-glucose and 5-O-acryloyl-1-methoxy-beta-D-ribofuranose revealed the influence of free hydroxyl groups in the monomer on the particle size during polymerization, a feature which is also apparently dependent on the amount of carbohydrate in the matrix. This methodology allows for a new, simple route to the synthesis of polymeric glyconanoparticles with potential applications in targeted drug delivery and materials development.     

Functionalization of gold and glass surfaces with magnetic nanoparticles using biomolecular interactions

Advances in nanotechnology have enabled the production and characterization of magnetic particles with nanometer-sized features that can be functionalized with biological recognition elements for numerous applications in biotechnology. In the present study, the synthesis of and interactions between self-assembled monolayers (SAMs) on gold and glass surfaces and functionalized magnetic nanoparticles have been characterized. Immobilization of 10-15 nm streptavidin-functionalized nanoparticles to biotinylated gold and glass surfaces was achieved by the strong interactions between biotin and streptavidin. Fluorescent streptavidin-functionalized nanoparticles, biotinylated surfaces, and combinations of the two were characterized by Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and electron and fluorescent microscopy to confirm that little or no functionalization occurred in nonbiotinylated regions of the gold and glass surfaces compared to the biotinylated sites. Together these techniques have potential use in studying the modification and behavior of functionalized nanoparticles on surfaces in biosensing and other applications.     

Dendrimer functionalized magnetic nanoparticles as a promising platform for localized hyperthermia and magnetic resonance imaging diagnosis

Magnetic iron oxide nanoparticles are a well-explored class of nanomaterials known for their high magnetization and biocompatibility. They have been used in various biomedical applications such as drug delivery, biosensors, hyperthermia, and magnetic resonance imaging (MRI) contrast agent. It is necessary to surface modify the nanoparticles with a biocompatible moiety to prevent their agglomeration and enable them to target to the defined area. Dendrimers have attracted considerable attention due to their small size, monodispersed, well-defined globular shape, and a relative ease incorporation of targeting ligands. In this study, superparamagnetic iron oxide nanoparticles were synthesized via a coprecipitation method. The magnetic nanoparticles (MNPs) had been modified with (3-aminopropyl) triethoxysilane, and then polyamidoamine functionalized MNPs had been synthesized cycling. Various characterization techniques had been used to reveal the morphology, size, and structure of the nanoparticles such as scanning electron microscopy, transmission electron microscope, X-ray diffraction analysis, and vibrating sample magnetometer, Fourier-transform infrared spectroscopy and zeta potential measurements. In addition, the cytotoxicity property of G3–dendrimer functionalized MNPs were evaluated using 3-[4,5-dimethylthiazol-2-yl]-2, 5-diphenyl tetrazolium bromide assay which confirmed the biocompatibility of the nanocomposites. Dendrimer functionalized MNPs are able to act as contrast agents for MRI and magnetic fluid hyperthermia mediators. A superior heat generation was achieved for the given concentration according to the hyperthermia results. MRI results show that the synthesized nanocomposites are a favorable option for MRI contrast agent. We believe that these dendrimer functionalized MNPs have the potential of integrating therapeutic and diagnostic functions in a single carrier.     

Enhanced oligonucleotide-nanoparticle conjugate stability using thioctic acid modified oligonucleotides

Metallic nanoparticles of gold functionalized with oligonucleotides conventionally use a terminal thiol modification and have been used in a wide range of applications. Although readily available, the oligonucleotide–nanoparticle conjugates prepared in this way suffer from a lack of stability when exposed to a variety of small molecules or elevated temperatures. If silver is used in place of gold then this lack of stability is even more pronounced. In this study we report the synthesis of highly stabilized oligonucleotide–nanoparticle conjugates using a simple oligonucleotide modification. A modified solid support was used to generate 3′-thioctic acid modified oligonucleotides by treatment with an N-hydroxysuccimidyl ester of thioctic acid. Unusually, both gold and silver nanoparticles have been investigated in this study and show that these disulphide-modified oligonucleotide probes offer significant improvements in nanoparticle stability when treated with dithiothreitol (DTT) compared with monothiol analogues. This is a significant advance in oligonucleotide–nanoparticle conjugate stability and for the first time allows silver nanoparticles to be prepared that are more stable than standard gold-thiol functionalized nanoparticles. This opens up the possibility of using silver nanoparticles functionalized with oligonucleotides as an alternative to gold.     

Cell-specific delivery of polymeric nanoparticles to carbohydrate-tagging cells

Carbohydrates on cell surfaces contribute a variety of communications between the cell and its environment, and they have been assumed to act as markers for cellular recognition. In this research, 2-methacryloyloxyethyl phosphorylcholine (MPC) polymer nanoparticles, which can react with specific carbohydrates of target cells, were newly prepared to serve as novel drug carriers. A water-soluble MPC polymer bearing hydrazide groups (PMBH) was synthesized by conventional radical polymerization. The MPC polymer showed amphiphilic nature and worked as an emulsifier to form nanoparticles. The nanoparticles covered with PMBH were prepared by the solvent evaporation method and exhibited monodispersity. They were approximately 200 nm in diameter and -2.0 mV in surface potential. According to a surface analysis of the nanoparticles, phosphorylcholine and hydrazide groups were observed, and the surface was fully covered with PMBH. Unnatural carbohydrates having ketone groups on human cervical carcinoma cell (HeLa) surfaces were expressed by treatment with levulinoyl mannosamine (ManLev). When the PMBH nanoparticles were in contact with the ManLev-treated HeLa cells, they accumulated in the cells. In contrast, the nanoparticles were not observed in native HeLa cells (without unnatural carbohydrates). These results indicate that the hydrazide groups of the nanoparticles selectively reacted to the ketone groups of the carbohydrates on the cell surface. The PMBH nanoparticles immobilized with anticancer drugs such as doxorubicin or paclitaxel were in contact with either ManLev-treated or untreated HeLa cells. The viability of the ManLev-treated HeLa cells was effectively reduced, but that of the untreated cells was preserved. This indicated that the anticancer drugs were selectively delivered to the ManLev-treated cells. Nonspecific cellular uptake of the nanoparticles was effectively reduced by MPC polymer coating. Furthermore, the immobilization processes of the drugs differed because of the solubility of the drugs. In conclusion, cellular-specific drug delivery by means of the novel nanoparticles was demonstrated with the selective reaction between unnatural carbohydrates on the cell surface and the hydrazide groups bearing the phosphorylcholine polymer nanoparticles.