基于金纳米粒子/聚阿魏酸/多壁碳纳米管修饰电极的DNA计时库仑法生物传感器的制备

构建了基于金纳米粒子/聚阿魏酸/多壁碳纳米管(AuNPs/PFA/MWCNTs)修饰电极的DNA计时库仑法生物传感器.利用循环伏安技术在多壁碳管修饰的玻碳电极表面上聚合一层阿魏酸,在恒电位条件下,在阿魏酸表面沉积金纳米粒子,巯基DNA作为探针通过金硫键固定在金纳米粒子表面.电化学交流阻抗技术(EIS)与扫描电镜(SEM...     

基于磁性纳米颗粒和金纳米粒子构建DNA电化学生物传感技术

本文构建了一种基于纳米粒子、茎环DNA和丝网印刷电极(SPCE)的电化学生物传感技术用于乳腺癌基因的快速、灵敏检测。该传感技术中,探针DNA的两端分别标记了巯基和生物素,巯基用于与金纳米粒子(AuNPs)作用,生物素用于与磁性纳米颗粒(MNPs)表面修饰的链酶亲和素作用以达到富集的目的,之后利用SPCE进行电化学检测。无目标DNA存在时,双标记DNA保持茎环结构,使得生物素分子很难和MNPs上的亲和素接触。一旦加入目标DNA,茎环结构打开,生物素得以与MNPs上的链霉亲和素发生特异性结合,形成的复合物(MNPs-DNA-AuNPs)通过磁性富集到SPCE表面,从而获得AuNPs的电化学信号。该DNA电化学生物传感对单碱基错配有良好的分辨能力,完全互补DNA的检出限为8.0×10-13 mol/L。     

利用DNA三维纳米结构对量子点功能化的有序调控

利用DNA纳米技术构建了内部具有空穴的DNA纳米立方体结构,将量子点封装在其内部,可达到在量子点的特定位点修饰数量可控的不同DNA序列的目的,进而精准控制量子点的结合位点数量和空间取向.为了验证构建的结构表面可以功能化不同的DNA序列,且可控地连接在不同位点,继续通过DNA之间的杂交对此结构进行了不同尺寸金纳米粒子的组装.通过透射电子显微镜观察发现,在此方法下由DNA三维纳米结构与量子点组建的复合结构不仅能控制连接的金纳米粒子数量,还能控制组装后的几何构型.本文方法适于构建多结合位点与功能化的量子点探针,在生物医学方面有巨大的应用潜力.     

基于直立碳纳米管大面积金粒子的DNA生物传感器用于早幼粒白血病/维甲酸受体α融合基因检测

基于直立碳纳米管上的大面积金粒子构建了新型的电化学DNA生物传感器,用于急性早幼粒细胞白血病PML/RARα融合基因的检测。首先在直立碳纳米管电极表面溅射金粒子,采用自组装方法将巯基修饰的单链DNA固定到电极上,将氨基修饰的单链DNA和羧基化的CdTe量子点通过酰胺缩合反应生成CdTe修饰的DNA探针,通过与目标DNA的双杂交反应形成三明治结构,利用差分脉冲阳极溶出伏安法检测电极表面捕获的CdTe量子点,从而对DNA进行定量分析。结果表明,电极上Cd2+峰电流与目标DNA浓度(1.0×10-12~1.0×10-8 mol/L)的对数值呈线性关系,线性方程为ipa(μA)=1.626+0.132lgC(mol/L)(R=0.996),检出限为4.0×10-13 mol/L(3σ)。传感器表现出良好的重现性和稳定性。     

金纳米粒子组装体的连续离散型纳米结构控制

采用柠檬酸钠还原氯金酸的方法,制备出粒径均一的金纳米粒子(AuNPs),通过加入二水合双(对-磺酰苯基)苯基膦化二钾盐(BSPP),增强了AuNPs体系的分散性与稳定性.选用直径为15和40nm的AuNPs,用不同序列巯基修饰的单链DNA连接到其表面,通过DNA链的杂交,形成不同结构的金纳米粒子组装体.通过改变加入DNA延长连接单元的比例,可以控制金纳米粒子组装体具有连续离散型的1∶1,2∶1和3∶1纳米结构.     

一种新型电化学DNA生物传感器的制备

将金纳米粒子(Au NPs)负载到氮掺杂石墨烯(N-G)的表面,用来修饰玻碳电极(GCE);以亚甲基蓝(MB)为指示剂,将探针DNA连接在电极表面,成功构建了DNA传感器。通过交流阻抗曲线(EIS)和差分脉冲曲线(DPV)的变化探讨了该传感器的选择性,重复性。得到了该电化学传感器的检测限为1.034×10~(-9)mol/L。     

还原响应型羧甲基纤维素基纳米药物载体的构建及其性能研究

近年来,刺激响应型智能纳米药物载体以其可控的药物释放、毒副作用小等优点,在药物递送领域引起广泛关注。本研究以羧甲基纤维素(CMC)为骨架材料,通过还原性二硫代二丙酰肼(TPH)连接疏水小分子胆酸(CA),合成两亲性高分子聚合物CMC-TPH-CA (CTC)。然后以10-羟基喜树碱(HCPT)为抗肿瘤模型药物,在水溶液中自组装制备CTC/HCPT纳米粒子,并对其物化性质及体外抗肿瘤活性进行了评价。结果表明,CTC/HCPT纳米粒子具有较高的包封率(～87.6%)及载药量(～21.4wt%),适当的粒径大小(～140nm)及低的溶血性(5%)。体外释放结果表明,CTC/HCPT纳米粒子具有明显的还原敏感性。最后,以LLC肿瘤细胞为模型,考察CTC/HCPT纳米粒子的体外细胞毒性。结果表明,相较于纯HCPT,CTC/HCPT纳米粒子的细胞杀伤作用有了明显的提升。     

三维有序金掺杂纳米TiO_2修饰电极用于抗肿瘤药物与DNA相互作用的研究

利用模板法在氧化铟锡(ITO)电极表面制备了三维有序多孔结构的金掺杂纳米Ti O2薄膜修饰电极(3DOM GTD/ITO),并在此修饰电极上成功固定小牛胸腺DNA(ct DNA),从而构建了一种新型的DNA生物传感器(DNA/3DOM GTD/ITO),并通过透射电镜(TEM)、扫描电镜(SEM)对修饰电极的表面形貌进行表征。采用电化学交流阻抗(EIS)法研究了ct DNA在3DOM GTD/ITO修饰电极表面的固定情况,结果表明,ct DNA已被成功地固定在3DOM GTD/ITO修饰电极表面。采用循环伏安法、微分脉冲伏安法等电化学方法研究了抗肿瘤药物槲皮素(Qu)在3DOM GTD/ITO修饰电极表面的电化学性质及与ct DNA的相互作用。结果表明,Qu在3DOM GTD/ITO修饰电极表面有1对准可逆的氧化还原峰,其氧化还原反应为2电子和2质子的转移过程。Qu可与固定在修饰电极上的ct DNA发生较强的结合作用,其结合常数(K)为3.61×106L/mol。循环伏安实验、紫外-可见吸收光谱、分子荧光光谱、圆二色性光谱均表明Qu与ct DNA之间的相互作用模式为嵌插作用。Qu与ct DNA的碱基结合具有序列选择性,对Qu与聚(d G-d C)及聚(d A-d T)的结合常数进行计算,得到结合常数比K(d G-d C)/K(d A-d T)=3.5,表明Qu与ct DNA发生嵌插作用时更倾向于结合在GC富集区域。     

NaYF_4：Yb,Er上转换荧光纳米粒子的表面修饰及其在免疫分析中的应用

稀土掺杂上转换荧光纳米材料因其近红外区激发,可见光区发射的特殊发光性能,在生物标记方面具有独特优势,可大幅度降低荧光背景.β-NaYF4：Yb,Er是目前已知的发光效率最高的上转换荧光纳米材料之一,已在生命分析及生物成像分析领域展现出了广阔的应用前景.然而,由于现有β-NaYF4：Yb,Er制备工艺多是在高温条件下于高沸点有机溶剂中反应制得,所得产品在水溶液中的分散性差,限制了其在生命分析中的广泛应用.本文采用聚丙烯酸（PAA）配体交换反应,对表面包覆油酸基团的疏水β-NaYF4：Yb,Er纳米粒子进行了有效的表面修饰.表面修饰后,上转换荧光纳米粒子表面的PAA具有众多游离羧基,使其在水溶液中具有良好的分散性.同时,由于羧基的存在,使得带有氨基的生物分子能够通过化学交联反应结合到纳米粒子表面.本文以PAA表面修饰后的β-NaYF4：Yb,Er纳米粒子为荧光探针,以磁珠作为免疫反应的载体,成功构建了一种新型免疫传感器,对模型靶标分子羊抗人IgG进行了灵敏检测.磁珠表面固定兔抗羊IgG,PAA修饰的β-NaYF4：Yb,Er纳米粒子表面连接人IgG,当样品中存在羊抗人IgG时,便会在磁珠表面形成（兔抗羊IgG-羊抗人IgG-上转换荧光纳米粒子标记的人IgG）三明治式免疫复合体,通过磁分离除去未反应的组分,在980nm激光激发下测定免疫复合体的上转换荧光强度,即可实现靶标分子的高灵敏分析,可检测到低至0.1ng/mL的羊抗人IgG.同时,以磁珠为载体的免疫复合体也可通过激光扫描共聚焦荧光显微镜进行荧光成像分析,背景荧光信号低,成像质量高.实验结果表明,PAA修饰的β-NaYF4：Yb,Er上转换荧光纳米粒子是一种理想的生物标记材料,有望在生物传感及生物成像分析领域获得广泛应用.     

pH响应性树枝状聚合物-金纳米粒子复合药物载体的制备

以表面接枝聚乙二醇链的聚酰胺胺树枝状聚合物(PEG-PAMAM)为纳米载体, 在其内部空腔包覆金纳米粒子, 在金纳米粒子表面连接硫辛酸改性的阿霉素(LA-DOX), 从而间接实现了抗癌药物在PEG-PAMAM内的高效负载. 同时, LA-DOX中的酰腙键提供pH响应性, 实现了药物的pH响应性释放. 紫外-可见(UV-Vis)光谱表明, 包覆金纳米粒子的PEG-PAMAM纳米载体对LA-DOX的负载能力显著增强. 体外细胞实验表明, 负载LA-DOX的树枝状聚合物-金纳米粒子复合药物载体具有较强的抗肿瘤能力.     

A DNA–Azobenzene Nanopump Fueled by Upconversion Luminescence for Controllable Intracellular Drug Release

Stimulus‐responsive drug release possesses considerable significance in cancer therapy. This work reports an upconversion‐luminescence‐fueled DNA–azobenzene nanopump for rapid and efficient drug release. The nanopump is constructed by assembling the azobenzene‐functionalized DNA strands on upconversion nanoparticles (UCNPs). Doxorubicin (DOX) is loaded in the nanopump by intercalation in the DNA helix. Under NIR light, the UCNPs emit both UV and visible photons to fuel the continuous photoisomerization of azo, which acts as an impeller pump to trigger cyclic DNA hybridization and dehybridization for controllable DOX release. In a relatively short period, this system demonstrates 86.7 % DOX release. By assembling HIV‐1 TAT peptide and hyaluronic acid on the system, targeting of the cancer‐cell nucleus is achieved for perinuclear aggregation of DOX and enhanced anticancer therapy. This highly effective drug delivery nanopump could contribute to chemotherapy development.     

Multivalent Aptamer-modified DNA Origami as Drug Delivery System for Targeted Cancer Therapy

In spite of great development in nanoparticle-based drug delivery systems(DDSs)for improved therapeutic efficacy,it remains challenging for effective delivery of chemotherapeutic drugs to targeted tumor cells.In this work,we report a triangle DNA origami as targeted DDS for cancer therapy.DNA origami shows excellent biocompatibility and stability in cell culture medium for 24 h.In addition,the DNA origami structures conjugated with multivalent aptamers enable for efficient delivery of anticancer drug doxorubicin(Dox)into targeted cancer cell due to their targeting function,reducing side effects associated with nonspecific distribution.Moreover,we also demonstrated that the multivalent aptamer-modified DNA origami loading Dox exhibits prominent therapeutic efficacy in vitro.Accordingly,this work provides a good paradigm for the development of DNA origami nanostructure-based targeted DDS for cancer therapy.     

Recent development in near infrared light-responsive polymeric materials for smart drug-delivery systems

Stimuli-responsive drug delivery systems (DDS) may overcome the drawbacks of conventional chemotherapy for cancer treatment. In particular, light-responsive polymer-based DDS may ensure spatio and temporal control in drug delivery. In this regard, near infrared (NIR) light triggered drug nanocarriers present several advantages when compared to UV–visible light triggered nanocarriers. This review surveys the recent development on the design, synthesis, functions, and applications of NIR photo-sensitive compounds in the development of long-wavelength light-responsive nanocarriers. Diverse NIR light responsive groups such as coumarin (CM), ortho-nitrobenzyl (ONB), 2-diazo-1,2-naphthoquinone (DNQ) and spiropyran (SP) derivatives and their photo-cleavage reaction mechanisms are discussed, as well as the use of indocyanine green (ICG) and its photo-thermal application. The loading into polymeric nanocarriers of up converting nanoparticles (UCNPs) which can convert NIR light into UV or visible light is also discussed. The described DDS are classified on the basis on the photo responsive groups. In details, the behavior of different polymeric materials such as micelles, hydrogels bearing photo responsive groups linked to bioactive molecules which are released under NIR light irradiation is reviewed and discussed. A section relative to commonly used instrument setup for drug release studies by NIR light irradiation is also presented for better understanding how the light has been used to irradiate in various experimental situations.     

Albumin-Albumin/Lactosylated Core-Shell Nanoparticles: Therapy to Treat Hepatocellular Carcinoma for Controlled Delivery of Doxorubicin

Doxorubicin (Dox) is the most widely used chemotherapeutic agent and is considered a highly powerful and broad-spectrum for cancer treatment. However, its application is compromised by the cumulative side effect of dose-dependent cardiotoxicity. Because of this, targeted drug delivery systems (DDS) are currently being explored in an attempt to reduce Dox systemic side-effects. In this study, DDS targeting hepatocellular carcinoma (HCC) has been designed, specifically to the asialoglycoprotein receptor (ASGPR). Dox-loaded albumin-albumin/lactosylated (core-shell) nanoparticles (tBSA/BSALac NPs) with low (LC) and high (HC) crosslink using glutaraldehyde were synthesized. Nanoparticles presented spherical shapes with a size distribution of 257 ± 14 nm and 254 ± 14 nm, as well as an estimated surface charge of −28.0 ± 0.1 mV and −26.0 ± 0.2 mV, respectively. The encapsulation efficiency of Dox for the two types of nanoparticles was higher than 80%. The in vitro drug release results showed a sustained and controlled release profile. Additionally, the nanoparticles were revealed to be biocompatible with red blood cells (RBCs) and human liver cancer cells (HepG2 cells). In cytotoxicity assays, Dox-loaded nanoparticles decrease cell viability more efficiently than free Dox. Specific biorecognition assays confirmed the interaction between nanoparticles and HepG2 cells, especially with ASGPRs. Both types of nanoparticles may be possible DDS specifically targeting HCC, thus reducing side effects, mainly cardiotoxicity. Therefore, improving the quality of life from patients during chemotherapy.     

Amplified Self‐Immolative Release of Small Molecules by Spatial Isolation of Reactive Groups on DNA‐Minimal Architectures

Triggering the release of small molecules in response to unique biomarkers is important for applications in drug delivery and biodetection. Due to low quantities of biomarker, amplifying release is necessary to gain appreciable responses. Nucleic acids have been used for both their biomarker‐recognition properties and as stimuli, notably in amplified small‐molecule release by nucleic‐acid‐templated catalysis (NATC). The multiple components and reversibility of NATC, however, make it difficult to apply in vivo. Herein, we report the use of the hybridization chain reaction (HCR) for the amplified, conditional release of small molecules from standalone nanodevices. We couple HCR with a DNA‐templated reaction resulting in the amplified, immolative release of small molecules. We integrate the HCR components into single nanodevices as DNA tracks and spherical nucleic acids, spatially isolating reactive groups until triggering. This could be applied to biosensing, imaging, and drug delivery.     

Amplified Self-Immolative Release of Small Molecules by Spatial Isolation of Reactive Groups on DNA-Minimal Architectures

Triggering the release of small molecules in response to unique biomarkers is important for applications in drug delivery and biodetection. Due to low quantities of biomarker, amplifying release is necessary to gain appreciable responses. Nucleic acids have been used for both their biomarker-recognition properties and as stimuli, notably in amplified small-molecule release by nucleic-acid-templated catalysis (NATC). The multiple components and reversibility of NATC, however, make it difficult to apply in vivo. Herein, we report the use of the hybridization chain reaction (HCR) for the amplified, conditional release of small molecules from standalone nanodevices. We couple HCR with a DNA-templated reaction resulting in the amplified, immolative release of small molecules. We integrate the HCR components into single nanodevices as DNA tracks and spherical nucleic acids, spatially isolating reactive groups until triggering. This could be applied to biosensing, imaging, and drug delivery.     

Liquid Marbles Based on Magnetic Upconversion Nanoparticles as Magnetically and Optically Responsive Miniature Reactors for Photocatalysis and Photodynamic Therapy

Magnetic liquid marbles have recently attracted extensive attention for various potential applications. However, conventional liquid marbles based on iron oxide nanoparticles are opaque and inadequate for photo‐related applications. Herein, we report the first development of liquid marbles coated with magnetic lanthanide‐doped upconversion nanoparticles (UCNPs) that can convert near‐infrared light into visible light. Apart from their excellent magnetic and mechanical properties, which are attractive for repeatable tip opening and magnetically directed movements, the resultant UCNP‐based liquid marbles can act as ideal miniature reactors for photodynamic therapy of cancer cells. This work opens new ways for the development of liquid marbles, and shows great promise for liquid marbles based on UCNPs to be used in a large variety of potential applications, such as photodynamic therapy for accelerated drug screening, magnetically guided controlled drug delivery and release, and multifunctional actuation.     

Towards site-specific nanoparticles for drug delivery application: preparation,characterization and release performance

Due to the uncontrollable drug release, traditional chemotherapies could cause great side-effects and are detrimental to normal tissue or organs. Therefore, to avoid those side-effects, drug delivery system (DDS) which is capable of releasing drug molecules at target area with controllable rate according to the development of the disease or to certain functions of the organism/biological rhythm, has attracted especially focus in recent years. In this research, we devoted our efforts in constructing a core–shell nanocomposite to meet the above requirements. The superparamagnetic Fe₃O₄ nanoparticles were chosen as the core to introduce the magnetic guiding as well as site-specific properties in this novel drug carrier. The core was further encapsulated by silica-based molecular sieve MCM-41 (briefly denoted as MS in this research), which was consisted by immense highly ordered hexagonal tunnels to offer plenty cavity for molecules of drug. A light stimuli-responsive ligand, which is a derivative from light-responsive precursor 4,5-diazafluoren-9-one (indicated in the paper as DAFO), was further connected to the MCM-41 tunnels. The ligand can be excited by light and will flip over, making the tunnels of MCM-41 switch from close to open with light on and light off. The nanocomposite thus became capable of releasing drug molecules at certain wavelength of light. In the final, the nanoparticles were tested via SEM/TEM, XRD, FT-IR spectra, thermogravimetry and N₂ adsorption/desorption to verify the structure. The MTT testing of our nanocomposite reveals no obvious cytotoxicity with non-morbid L929 murine fibroblast cells line, indicating that it could be used as a DDS candidate. The cargo releasing behaviors were studied on cytarabine loaded composite: DAFO@MS@Fe₃O₄ in simulated body fluids.     

Biocompatible NaYF4:Yb,Er upconversion nanoparticles: Colloidal stability and optical properties

Currently, highly luminescent colloidal upconversion nanoparticles (UCNPs) have expanded an increasing interest of researchers because of their facilitating lability in the biomedical/clinical field. In this study, NaYF₄:Yb,Er UCNPs are prepared by eco-friendly metal complexation-based thermal decomposition method at a lower temperature in aqueous media. The phase structure, crystallinity, phase purity, morphology, colloidal dispersibility, surface structure, surface charge, and optical and luminescent properties were evaluated carefully by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), energy dispersive x-ray analysis (EDX), Thermogravimetric analysis (TGA), zeta potential, Fourier transform infrared (FTIR), UV/visible and photoluminescent spectroscopic techniques. XRD pattern shows a pure single-phase cubic structure with an average grain size of 30–35 nm. TEM and SEM micrographs exhibited irregularly shaped spherical morphologies, porous surface structures highly aggregated UCNPs with the narrow-size distribution. Positive zeta potential has shown value signifying high absorption in the visible region which indicates particle's good colloidal stability in aqueous media. Under NIR-laser light excitation, the UCNPs emit strong UC emission transitions in the visible region. A broad infrared absorption peak of hydroxyl groups (–OH) in FTIR spectrum and mass loss at a lower temperature in TGA verified the surface functionality of UCNPs, with high colloidal stability, and excellent biocompatibility in aqueous media. In terms of their surface characteristics and high luminescent properties, the NaYF₄:Yb,Er UCNPs could be interestingly applied in tagging of biomolecules, drug delivery, proteins labeling, and therapeutic and thermostats applications.     

Rational design and biomedical applications of DNA-functionalized upconversion nanoparticles

In this review, we mainly introduced recent progress of DNA-functionalized upconversion materials, providing an overview of the design and applications in biosensing, bioimaging and disease therapy. The challenges and future perspectives are also discussed, aiming to promote their applications in materials science and biomedicine.