Application of Aptamers in Biomedicine

Corresponding author e-mail:[email protected]; [email protected][中文文摘]核酸适体是经配体指数富集系统进化技术(SELEX)筛选获得的一类能够特异性地结合离子、分子,甚至整个细胞的单链DNA或者RNA分子。本文介绍了核酸适体及相关筛选技术SELEX;综述了近年来以提高筛选效率和效果为目标的核酸适体筛选技术新进展;列举了核酸适体在无机离子、小分子、生物大分子和肿瘤细胞检测、肿瘤标记物的发现等方面的应用;讨论了基于核酸适体的靶向治疗策略;最后对核酸适体在生物医学上的应用前景进行了展望。[英文文摘]Aptamers are a new class of nucleic acid probes,which are ssDNA /RNA molecules selected to target a wide range of ions,molecules and even cells through SELEX(systematic evolution of ligands by exponential enrichment) technique.This paper presents aptamers and traditional selection approaches;summarizes recent efforts in developing new aptamer selection strategies;reviews new approaches for biomedical analysis,disease biomarker discovery and target therapy.Finally,the potential of aptamers in biomedicine is also discussed.国家重点基础研究发展计划(973)项目(No.2010CB732400); 福建省自然科学基金项目(No.2008J0107)资

风沙两相流中的跃移运动

从单个跃移沙粒在气流中的运动方程出发导出了风沙两相流中沙粒相速度分布函数的Ｂoltzmann方程；并以此将单相颗粒流理论中的广义平衡方程推广到气固两相流的情形。提出用Grad方法将粒子相速度分布函数展成无穷级数，并引入Gauss分布取代单相颗粒流中传统的Maxwell分布。在保留到3次项的情况下，建立了气体－颗粒两相湍流边界层三阶矩封闭理论的动力学方程组。并在风洞频闪摄影实验的基础上，对理论进行简化，得到便于工程应用的简化方程

Study on the Determination of Chitosan by Using Alizarin Red as An Electrochemical Activity Probe

建立了以茜素红(AR)为电活性探针间接测定无电活性壳聚糖(CS)的新方法。研究了AR及其与CS的结合物AR-CS于0.1 mol/L HAc-NaAc(pH 4.5)缓冲溶液中在玻碳电极(GCE)上的电化学行为。AR与CS-AR在GCE上均能形成一准可逆的吸附伏安峰(Vpc=-0.46 V,Vpa=-0.41 V,ΔVp=0.05 V)。测定了X、α、Ks等电化学参数。实验表明,CS在低浓度(1.25×10-8~2.5×10-7mol/L)和高浓度(2.5×10-7~1.25×10-5mol/L)的条件下对体系的峰电流分别具有线性增敏和减敏效应。采用标准加入法测定了不同样品中壳聚糖的含量,其回收率在97%~102%之间,结果满意。 A new method to determine chitosan （CS） indirectly was established by using alizarin red （AR） as an electrochemical activity probe. The electrochemical behaviour of the interaction between AR and CS was investigated in 0. 1 mol/L HAc - NaAc buffer solution（pH 4.5） on the glassy carbon electrode（GCE） by voltammetry. The results show that AR and AR - CS complex can be easily reduced or oxidized on the GCE and they have a pair of well-defined quasi-reversible waves （ Vpc = -0.45 V, Vpa =-0.41V, △ Vp =0. 04 V） with adsorption characteristics. The electrochemical parameters such as proton numbers （X）, electron transfer coefficient（α）, reaction rate constant（K） were measured by cyclic voltammetry. The increase and decrease of reductive peak currents of AR are proportional to CS concentration in the range of 1.25 × 10^-8 - 2.5 × 10^- 7 mol/L and 2.5 ×10^-7- 1.25×10^-5 mol/L, respectively. The method has been successfully used for the determination of CS in different samples by standard addition. The recovery was measured to be 97% - 102%.国家自然科学基金资助项目(20475068);广西壮族自治区自然科学基金资助项目(0141037,0342018

An amperometric hydrogen peroxide biosensor based on chitosan/silica sol-gel composite films incorporating horseradish peroxidase

利用溶胶 凝胶法制备壳聚糖 二氧化硅有机无机复合杂化膜,用于对辣根过氧化酶进行固定,制得测定H2O2的电流型生物传感器。以1mmol/LK4Fe(CN)6作为电子媒介体。研究了各种因素如壳聚糖与二氧化硅的比率、pH、温度、工作电位等对传感器响应电流的影响。计时电流法测定H2O2的线性范围为2.0×10-6～6.8×10-4mol/L,检出限为8.0×10-7mol/L。测得酶催化动力学参数米氏常数Km=0 87mmol/L。用该法对实际样品进行了测定。Abstract :A new type of chitosan/silica sol-gel organicinorganic hybrid composite film was developed for the fabrication of an amperometric hydrogen peroxide(H2O2) biosensor.The composite film was used to immobilize horseradish peroxidase(HRP)on a gold disk electrode . Hexacyanoferrate (K4Fe(CN)6)was added to the solution as an electron mediator .Effects of some experimental conditions such as the ratio of chitosan to silica , pH , temperature and applied potential on the response current of the biosensor were investigated .The biosensor had a fast response of less than 10 s and linear calibration range of 2 .0 ×10 -6 ～ 6 .8 ×10 -4 mol/L with detection limit of 8 .0 ×10 -7 mol/L for H2O2 .The Michaelis-Menten constant Km was found to be 0.87 mmol/L .This method was used to determine the content of H2O2 in the real sample .广东省(011105,031577);广西壮族自治区(0141037,0342018);自然科学基金;广西民族学院引进人才启动基金(OHHX00002)资助项

Determination of Nitrofurantoin and Its Electrochemical Behavior at Cobalt Ion Implantation Modified Glassy Carbon Electrode

呋喃妥因 (NFT)在 0 .1mol/LHAc NaAc (pH 4 .0 )溶液中于钴 /玻碳 (Co/GC)离子注入修饰电极上产生一灵敏的伏安还原峰 ,峰电位为 - 0 .2 6V(vs.Ag/AgCl) ,峰电流与NFT浓度在 6 .0× 10 -8～ 5 .0× 10 -6mol/L范围内呈线性关系 (r =0 .9987) ,检出限为 1.0× 10 -8mol/L。用线性扫描伏安法和循环伏安法研究了NFT的伏安行为、吸附特性和电极反应机理。测定了电子转移数 (n =4 )、转移系数 (α =0 .5 8)和参与反应的质子数 (X =4 )等电化学参数。结果表明该电极过程为一具有吸附性的不可逆过程。该法用于片剂中NFT含量的测定 ,得到满意的结果。用标准加入法测得该法的回收率为 94 .0 %～ 98.5 %。In 0.1 mol/L HAc-NaAc buffer (pH 4.0) solution, a sensitive reductive peak of nitrofurantion was obtained by linear sweep voltammetry on the cobalt/glassy carbon (Co/GC) ion implantation modified electrode. The peak potential was -0.26 V ( vs. Ag/AgCl). The linear range between the peak current and the concentration of nitrofurantoin was 6.0 x 10(-8) similar to5.0 x 10(-6) mol/L (r = 0.9987). The detection limit was 1.0 x 10(-8) mol/L. The voltammetric behaviour, adsorptive characteristic and the electrode reaction mechanism of nitrofarantoin were studied by means of linear sweep and cyclic voltammetry. Some electrochemical parameters such as electron transfer numbers (n = 4), electron transfer coefficient (alpha = 0.58) and proton numbers (X = 4) have been determined. The electrode reduction process of nitrofurantoin at Co/GC was irreversible with adsorptive characteristic. This method has been used to determine the content of nitrofurantoin in medical tablets. The recovery was determined to be 94.0% similar to 98.5% by means of standard addition method.广东省自然科学基金 (No .0 1110 5 ,0 3 15 77);广西壮族自治区自然科学基金 (No .0 14 10 3 7,0 3 42 0 18);广西民族学院引进人才启动基金 (No .OHHX0 0 0 0 2 )资助项

Amperomertric Glucose Biosensor Based on Sol-gel Chitosan /Sil ica HybridMaterial

近年来，基于溶胶-凝胶技术的有机/无机杂化复合材料由于具有有机物的柔性和易修饰性，以及无机物的刚性和稳定性等，因此有利于保持生物分子的活性和生物传感器的研制．壳聚糖(CS)具有易成膜性和生物相容性，其在生物传感器中的研究已受到重视．本文通过原位溶胶-凝胶(Sol-gel)技术，Abstract　A new type of so l-gel /o rg anic hybrid composi te film based o n chi tosan ( CS ) w ith methy trimetho xy silane ( M TOS ) was dev eloped fo r the fabricatio n of an amperomet ric g lucose biosenso r. The hybrid composi te fi lm w as used to immo bilize gluco se oxidase( GOD) o n the surface of Prussian Blue( PB) -modi fied g lass carbo n electrode. Effect s of some ex perimental conditions such as pH, tempera ture a nd applied potential etc. on the current response of the bio sensor w ere investiga ted. The bio sensor has a fast respo nse less than 10 s a nd linear calibratio n ra ng e from 5. 0× 10- 6 to 2. 4× 10- 3 mo l /L w ith detection limi t of 1. 0× 10- 6 mo l /L. The apparent Michaelis-Menten constant Km is found to be 3. 2× 10- 3 mol /L. The activa tion energy fo r enzymatic reactio n is calculated to be 21. 9 k J /mol. The bio sensor has a high sensitivi ty ( 420 μA· mol- 1 · L) , long-term stabi li ty and g ood selectivi ty. This method has been used to determine the co ntent of g lucose in the rea l blood samples.广东省自然科学基金 (批准号 :0 1110 5,0 3 15 77);广西壮族自治区自然科学基金 (批准号 :0 14 10 3 7,0 3 42 0 18)资

Electrochemical Behaviour of the Interaction Between Chitosan and Al izarin

Abstract　The interaction betw een Ali zarin red ( AR) and Chi tosan ( CS) w as inv estigated in 0. 1 mol /L HAc-NaAc buf fer solution ( pH= 4. 5) on the glassy carbo n elect rode ( GC) by cyclic and square wave voltammet ry. The results show that bo th AR and AR-CS complex have a well-defined quasi-rev ersible redox wave( Vpc= - 0. 46 V , Vpa= - 0. 41 V ) with adsorption characteristics. Electron t ransfer coefficient (T) and reaction rate constant (Ks ) of AR and AR-CS were measured by cyclic voltammet ry. The maximum binding numbers m betw een AR and CS was found to be 2 500. The ex periment results confirmed that low er concentratio n of CS can enhance the detection sensitivity , w hile hig her concent ration of CS can low er the detection sensitivi ty. In the presence of 2. 0× 10- 5 mol /L AR, the peak current of sy stem are proportional to CS concentration in the rang e of 1. 25× 10- 8～ 2. 5× 10- 7 mol /L, and inv ersely proportional to CS concentration in the rang e of 2. 5× 10- 7～ 1. 25× 10- 5 mol /L, respectiv ely. The binding interaction mechanism w as also discussed.国家自然科学基金(批准号:20475068);广西壮族自治区自然科学基金(批准号:0141037,0342018)资