With the highly interdisciplinary of research and great development of microfabrication techniques,patterned surfaces have attracted great attention of researchers since they possess specific regularity and orderness of structures.In recent years,series of two dimensional patterned structures have been successfully fabricated,and widely used in anti-reflection,anti-fogging,self-cleaning,and sensing,etc.In the meantime,patterned structures have been gradually used in biologically relative fields such as biomaterials,aiming to deepen the perception of organism and understand the vital movements of human body.In this review,we provide a brief introduction on current status of techniques for two dimensional patterns fabrication,the applications of patterned surfaces in biologically related fields,and give out a prospective on the development of these patterned surfaces in the future.
Large-area deep-silver-nanowell arrays （d-AgNWAs） for plasmonic sensing were manufactured by combining colloidal lithography with metal deposition. In contrast to most previous studies, we shed light on the outstanding sensitivity afforded by deep metallic nanowells （up to 400 nm in depth）. Using gold nanohole arrays as a mask, a silicon substrate was etched into deep silicon nanowells, which acted as a template for subsequent Ag deposition, resulting in the formation of d-AgNWAs. Various geometric parameters were separately tailored to study the changes in the optical performance and further optimize the sensing ability of the structure. After several rounds of selection, the best sensing d-AgNWA, which had a Ag thickness of 400 nm, template depth of 400 nm, hole diameter of 504 nm, and period of 1 ~m, was selected. It had a sensitivity of 933 nm.RIU-1, which is substantially higher than those of most common thin metallic nanohole arrays. As a proof of concept, the as-prepared structure was employed as a substrate for an antigen-antibody recognition immunoassay, which indicates its great potential for label-free real-time biosensing.
Xueyao LiuWendong LiuLiping FangShunsheng YeHuaizhong ShenBai Yang
Poly(N-isopropylacrylamide)(PNIPAAm)-based thermo-responsive surfaces can switch their wettability(from wettable to non-wettable) and adhesion(from sticky to non-sticky) according to external temperature changes. These smart surfaces with switchable interfacial properties are playing increasingly important roles in a diverse range of biomedical applications; these controlling cell-adhesion behavior has shown great potential for tissue engineering and disease diagnostics. Herein we reviewed the recent progress of research on PNIPAAm-based thermo-responsive surfaces that can dynamically control cell adhesion behavior. The underlying response mechanisms and influencing factors for PNIPAAm-based surfaces to control cell adhesion are described first. Then, PNIPAAm-modified two-dimensional flat surfaces for cell-sheet engineering and PNIPAAm-modified three-dimensional nanostructured surfaces for diagnostics are summarized. We also provide a future perspective for the development of stimuli-responsive surfaces.
Light-activated dynamic variations have promoted the development of smart interfaces, especially nano-biointerfaces. In this article, the near-infrared （NIR）- responsive surface for controlling cell adhesion was designed by grafting a thermal responsive polymer （poly（N-isopropylacrylamide）, PNIPAM） onto silicon nanowires （SiNWs） instead of the traditional photosensitive moieties. NIR induced the photothermal effect of the SiNWs, and the local heat induced thermodynamic phase transformation of PNIPAM. With the application of NIR radiation, the surface turned to a hydrophobic state, and restored to the hydrophilic state when NIR was switched off, leading to reversible cell adhesion and release. The switchable wettability of the surface and cell adhesion/release occurred efficiently even after 20 cycles. Proteins were anchored on the surface via hydrophobic interactions using NIR; further connection of a cell-capture agent helped in achieving specific cell capture. This dynamic control of cell adhesion via NIR may provide new clues for designing functional nano-biointerfaces.
An important and difficult issue is simultaneously identifying the detailed locations of various molecules on the cell surface, as this identification requires a synergistic effect between more than one molecule in a living cell. Au nanoparticles (NPs) with different shapes can be readily recognised under low vacuum scanning electron microscopy (lvSEM). Anisotropic Au nanorods (NRs) possess unique surface plasmon resonance (SPR) properties, which can be further utilised for two photon luminescence (TPL) and other optical imaging techniques. In this paper, Au NRs and Au nanooctahedra (Au NOs) are introduced as biomarkers for ICAM-1 and Integrin β1. Combined with the advantages of lvSEM, this multiple-labelling method is a new method for studying the interactions between specific, functional molecules.
The micro/-nanoscaled functional biointerfaces aroused much interest of their key unit element to present unique functions. So far it is still difficult to describe the whole picture of this process. More and more evidences are beginning to support the theory of ‘‘mirco/-nanotopography-coupled-mechanical(TCM) action'' into functional biointerfaces.Herein, we aim to highlight TCM action on varied micro/-nanoscaled functional biointerfaces, namely to achieve better understanding of micro/-nanoscaled structures by introducing interfacial mechanical behaviors. In this article, recent progressions on ‘‘TCM on air/liquid/solid-phase biointerfaces in nature'', ‘‘in vivo TCM behaviors at micro/-nanoscales' ',‘‘TCM in micro/-nanoscaled artificial surface with living Cells' ' and ‘‘topography, interfacial curvature, mechanics' 'are reviewed. Certain new concepts of ‘‘TCM action based on spatial curvature'', ‘‘medically functional biointerfaces' ' and‘‘biomechanopharmacology'' are also proposed.
