递呈BAC_5单抗识别位点的M_(13)噬菌体克隆系的建立

【目的】获得可递呈抗低分化和未分化癌细胞单克隆抗体 (BAC5单抗 )抗原表位的M13 噬菌体克隆系。【方法】以BAC5单抗为靶抗体 ,对由M13 噬菌体构建的随机 12肽文库进行生物淘洗。用抗体竞争方法从阳性克隆中选出与BAC5单抗结合率较高的克隆系。通过ELISA方法检测BAC5单抗对上述克隆的选择性识别。【结果】经过 3轮淘洗 ,获得的阳性克隆率为77% (35 /4 5 )。来自C2、C17和C2 9号克隆的噬菌体对外加BAC5单抗的结合率分别为 71 6 %、49 4%和 6 4 0 % ,高于其它阳性克隆。BAC5单抗与来自上述 3个克隆的噬菌体呈阳性反应 ,与来自辅助型M13 株的噬菌体 (VCSM13 )和淘洗前的文库噬菌体(RPLM13 )呈阴性反应。【结论】来自C2、C17和C2 9号克隆的噬菌体有可能递呈与BAC5单克隆抗相关的抗原表位。

M13 Bacteriophage-Polymer Nanoassemblies as Drug Delivery Vehicles

Poly（caprolactone-b-2-vinylpyridine） （PCL-P2VP） coated with folate-conjugated M13 （FA-M13） provides a nanosized delivery system which is capable of encapsulating hydrophobic antitumor drugs such as doxorubicin （DOX）. The DOXqoaded FA-M13-PCL-P2VP assemblies had an average diameter of approximately 200 nm and their structure was characterized using transmission electron microscopy, scanning electron microscopy, and dynamic light scattering. The particles were stable at physiological pH but could be degraded at a lower pH. The release of DOX from the nanoassemblies under acidic conditions was shown to be significantly faster than that observed at physiological pH. In addition, the DOX-loaded FA-M13-PCL-P2VP particles showed a distinctly greater cellular uptake and cytotoxicity against folate-receptor-positive cancer cells than folate-receptor-negative cells, indicating that the receptor facilitates folate uptake via receptor-mediated endocytosis. Furthermore, the DOX-loaded particles also had a significantly higher tumor uptake and selectivity compared to free DOX. This study therefore offers a new way to fabricate nanosized drug delivery vehicles.

Bacteriophage M13 as a Scaffold for Preparing Conductive Polymeric Composite Fibers

Using biological templates to build one-dimensional functional materials holds great promise in developing nanosized electrical devices,sensors,catalysts,and energy storage units.In this communication,we report a versatile assembly process for the preparation of water-soluble conductive polyaniline(PANi)/M13 composite nanowires by employing the bacteriophage M13 as a template.The surface lysine residues of M13 can be derivatized with carboxylic groups to improve its binding ability to the aniline;the resulting modifi ed M13 is denoted as m-M13.Highly negatively-charged poly(sulfonated styrene)was used both as a dopant acid and a stabilizing agent to enhance the stability of the composite fi bers in aqueous solution.A transparent solution of the conductive PANi/m-M13 composite fi bers can be readily obtained without any further purifi cation step.The fi bers can be easily fabricated into thin conductive fi lms due to their high aspect ratio and good solubility in aqueous solution.This synthesis discloses a unique and versatile way of using bionanorods to produce composite fi brillar materials with narrow dispersity,high aspect ratio,and high processibility,which may have many potential applications in electronics,optics,sensing,and biomedical engineering.

Application of an M13 bacteriophage displaying tyrosine on the surface for detection of Fe^(3+) and Fe^(2+) ions

Ferric and ferrous ion plays critical roles in bioprocesses,their influences in many fields have not been fully explored due to the lack of methods for quantification of ferric and ferrous ions in biological system or complex matrix.In this study,an M13 bacteriophage(phage) was engineered for use as a sensor for ferric and ferrous ions via the display of a tyrosine residue on the P8 coat protein.The interaction between the specific phenol group of tyrosine and Fe^(3+)./ Fe^(2+).was used as the sensor.Transmission electron microscopy showed aggregation of the tyrosine-displaying phages after incubation with Fe^(3+) and Fe^(2+).The aggregated phages infected the host bacterium inefficiently.This phenomenon could be utilized for detection of ferric and ferrous ions.For ferric ions,a calibration curve ranging from 200 nmol/L to 8 μmol/L with a detection limit of 58 nmol/L was acquired.For ferrous ions,a calibration curve ranging from 800 nmol/L to 8μmol/L with a detection limit of 641.7 nmol/L was acquired.The assay was specific for Fe^((3+)) and Fe^((2+)) when tested against Ni^(2+),Pb^(2+),Zn^(2+),Mn^(2+),Co^(2+),Ca^(2+),Cu^(2+),Cr^(3+),Ba^(2+),and K^+.The tyrosine displaying phage to Fe^(3+) and Fe^(2+) interaction would have plenty of room in application to biomatenals and bionanotechnology.

A new method for quantitative analysis of M13 bacteriophage by atomic force microscopy

Quantitative analysis is essential for virus research,especially in determining the virus titer.The classical method plaque assay is time-consuming,complex,and difficult for the phages that cannot form apparent plaque on the solid medium.In order to realize rapid and effective detection,a new method combining atomic force microscopy(AFM)observation and mathematical calculation is established.In this research,M13 phages with an appropriate dilution ratio were observed and counted by AFM.Based on the counting results,the titer of M13 phages can be calculated simply through mathematical substitution.Instead of cultivating overnight in plaque assay,this new method can be implemented within a few hours.Moreover,it is a method that can achieve visualization for titer determination and have the potential to determine the phages that fail to form apparent plaque,which is significant in virus quantitative assessment.

Direct detection and measurement of wall shear stress using a filamentous bio-nanoparticle

The wall shear stress （WSS） that a moving fluid exerts on a surface affects many processes including those relating to vascular function. WSS plays an important role in normal physiology （e.g. angiogenesis） and affects the microvasculature＇s primary function of molecular transport. Points of fluctuating WSS show abnormalities in a number of diseases; however, there is no established technique for measuring WSS directly in physiological systems. All current methods rely on estimates obtained from measured velocity gradients in bulk flow data. In this work, we report a nanosensor that can directly measure WSS in microfluidic chambers with sub-micron spatial resolution by using a specific type of virus, the bacteriophage M13, which has been fluorescently labeled and anchored to a surface. It is demonstrated that the nanosensor can be calibrated and adapted for biological tissue, revealing WSS in micro-domains of cells that cannot be calculated accurately from bulk flow measurements. This method lends itself to a platform applicable to many applications in biology and microfluidics.