tailieunhanh - Báo cáo hóa học: " AFM-assisted fabrication of thiol SAM pattern with alternating quantified surface potential"

Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: AFM-assisted fabrication of thiol SAM pattern with alternating quantified surface potential | Moores et al. Nanoscale Research Letters 2011 6 185 http content 6 1 185 o Nanoscale Research Letters a SpringerOpen Journal NANO EXPRESS Open Access AFM-assisted fabrication of thiol SAM pattern with alternating quantified surface potential Bradley Moores1 Janet Simons2 Song Xu3 Zoya Leonenko1 2 Abstract Thiol self-assembled monolayers SAMs are widely used in many nano- and bio-technology applications. We report a new approach to create and characterize a thiol SAMs micropattern with alternating charges on a flat gold-coated substrate using atomic force microscopy AFM and Kelvin probe force microscopy KPFM . We produced SAMs-patterns made of alternating positively charged negatively charged and hydrophobic-terminated thiols by an automated AFM-assisted manipulation or nanografting. We show that these thiol patterns possess only small topographical differences as revealed by AFM and distinguished differences in surface potential 20-50 mV revealed by KPFM. The pattern can be helpful in the development of biosensor technologies specifically for selective binding of biomolecules based on charge and hydrophobicity and serve as a model for creating surfaces with quantified alternating surface potential distribution. Background Thiol self-assembled monolayers SAMs are promising for many nano- and bio-technology applications as they offer a reliable method to produce surfaces with desirable properties. These properties can be used for specific and non-specific binding of biomolecules and nanoparticles and therefore can serve as useful templates for nano- and micro-fabrication. The first systematic study of thiol chemicals was reported by Zisman and coauthors 1 and has since been investigated by many researchers including a detailed review by Chechik et al 2 . SAMs can be defined as molecular assemblies that are formed spontaneously be the immersion of an appropriate substrate into a solution of an active surfactant in an organic solvent 3 . Thiols