Ahmad Gul, Dickerson Matthew B, Cai Ye, Jones Sharon E, Ernst Eric M, Vernon Jonathan P, Haluska Michael S, Fang Yunnan, Wang Jiadong, Subramanyam Guru, Naik Rajesh R, Sandhage Kenneth H
School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332-0245, USA.
J Am Chem Soc. 2008 Jan 9;130(1):4-5. doi: 10.1021/ja0744302. Epub 2007 Dec 8.
A 12-mer peptide, identified through phage display biopanning, has been used for the first time to induce the rapid formation of ferroelectric (tetragonal) nanocrystalline BaTiO3 at room temperature from an aqueous salt precursor solution at near neutral pH. BaTiO3 is widely used in capacitors, thermistors, displays, and sensors owing to its attractive dielectric, ferroelectric, pyroelectric, optical, and electrochemical properties. Two 12-mer peptides (BT1 and BT2) were selected from a phage-displayed peptide library via binding to tetragonal BaTiO3 powder. While these peptides possessed various types of amino acids, 8 of the 12 amino acids were common to both peptides. Each of these peptides induced the formation of faceted nanoparticles (50-100 nm diameter) from an aqueous precursor solution. X-ray diffraction and selected area electron diffraction patterns obtained from these faceted nanoparticles were consistent with the BaTiO3 compound. Rietveld analyses of the X-ray diffraction patterns yielded good fits to tetragonal crystal structures, with the BaTiO3 formed in the presence of the BT2 peptide exhibiting the most tetragonal character. A coating of the latter BaTiO3 nanoparticles exhibited polarization hysteresis (a well-known characteristic of ferroelectric materials) at room temperature and a relative permittivity of 2200. Such rapid, peptide-induced precipitation at room temperature provides new opportunities for direct BaTiO3 formation on low-melting or reactive materials (e.g., plastics, cloths, bio-organics) and the low temperature integration of BaTiO3 into electronic devices (e.g., on silicon or flexible polymer substrates).
通过噬菌体展示生物淘选鉴定出的一种12肽，首次被用于在室温下，从接近中性pH值的盐水前驱体溶液中诱导铁电（四方）纳米晶BaTiO₃的快速形成。由于其具有吸引人的介电、铁电、热电、光学和电化学性质，BaTiO₃被广泛应用于电容器、热敏电阻、显示器和传感器中。通过与四方BaTiO₃粉末结合，从噬菌体展示肽库中筛选出两种12肽（BT1和BT2）。虽然这些肽含有各种类型的氨基酸，但两种肽的12个氨基酸中有8个是相同的。每种肽都能从前驱体水溶液中诱导形成多面纳米颗粒（直径50-100nm）。从这些多面纳米颗粒获得的X射线衍射和选区电子衍射图谱与BaTiO₃化合物一致。对X射线衍射图谱进行的Rietveld分析与四方晶体结构拟合良好，在BT2肽存在下形成的BaTiO₃具有最强的四方特性。后一种BaTiO₃纳米颗粒涂层在室温下表现出极化滞后（铁电材料的一个众所周知的特性），相对介电常数为2200。这种在室温下由肽诱导的快速沉淀为在低熔点或活性材料（如塑料、布料、生物有机物）上直接形成BaTiO₃以及将BaTiO₃低温集成到电子器件（如在硅或柔性聚合物基板上）提供了新的机会。
