Surface Functionalization of SU-8 Vertical Waveguide for Biomedical Sensing: Bacteria Diagnosis

Abstract

In this paper, we present an SU-8 based evanescent waveguide with a vertical structure as a biomedical sensor. The waveguide is designed vertically to generate evanescent waves on both left and right surfaces for sensing. It is fabricated by E-beam lithography with only one-step process which has the advantage of a better surface quality compared with commonly used dry etching methods. Furthermore, fabrication time and cost is cut down greatly. The surface of the designed waveguide can be functionalized with antibodies to immobilize specific bacteria on it. After surface functionalization and incubation with E. coli solutions of different concentrations, the waveguides absorption was measured. The results demonstrate that the waveguide is sensitive to E. coli concentration changes. In addition, tapers were designed and added to the waveguide to relieve the alignment tolerance for the aim of making a plug-and-play bedside diagnostic system.

Polymeric Nanoneedle Arrays Mediate Stiffness‐Independent Intracellular Delivery

“…The optical properties of polymeric NNs offer an alternate imaging platform to opaque vertically aligned NNs such as Si NNs, requiring no fluorescence staining of the NNs for visualization by means of an inverted live‐cell imaging microscope. [ 28b,54 ]…”

“…These features have made polymeric NNs a functional and versatile platform for a variety of cellular manipulations and interrogations. [ 25 ] So far, polymeric NNs have been used in intracellular signaling studies, [ 26 ] antibacterial and antibiofouling applications, [ 27 ] biomedical sensing and cellular probing, [ 28 ] and neuron and stem cell research. [ 29 ]…”

Physiochemically distinct SU-8 surfaces tailor Xylella fastidiosa cell-surface holdfast and colonization

“…Although surface motility can be a crucial strategy in bacterial growth whereby bacteria seek nutrients and enable new colonies [39], the present results emphasize this mechanism by which the necessity of the affinity of pili to the substrate is required. Overall, the study provides comprehensive understanding of bacterial-SU-8 surface interaction which could lead to design effective strategies for the fabrication of SU-8 based various unique devices for biomedical applications [8][9][10][11]14].…”

“…The SU-8 epoxy polymer is one such material that has great potential for fabrication of high aspect ratio of micro/nanostructured scaffolds for lab-on-a-chip devices [1][2][3][4]. In particular, SU-8 has been used as an impressive platform for the development of various smart biomedical devices including biosensors [5][6][7], bacterial diagnosis [8][9][10], cantilever [11], bioelectrodes [12] and microrobots [13,14] owing to its excellent optical and mechanical properties with chemical stability even against acids [3,15,16]. Moreover, SU-8 nanostructures with tunable high aspect ratios have been fabricated and used for eukaryote cell interface and for simultaneous visualization of the traction force and focal adhesion of eukaryotic cells [17].…”

“…Whilst the SU-8 properties combined with its biocompatibility facilitates its application in bio-related material interfaces [6][7][8][9]17,18], how the surface properties of SU-8 affect bacterial adhesion and successive proliferation is poorly understood.…”