A microfluidic chip that incorporates colloidal crystals inside a microchannel system for on‐chip integration of optical components is presented. It is demonstrated that the use of fluorescent spheres offers added advantages and functionality to the colloidal crystal array. Multifunctional optical components are demonstrated that are able to serve as a reference wavelength calibration line in measured reflectance spectra. Integrating colloidal crystals with varying filtering effects into a microfluidic chip enables selective transmission or blocking of a particular range of wavelengths locally. In addition, combinations of double‐band colloidal crystal filters provide further tunability of the working wavelength for on‐chip detection applications.

We report the design and fabrication of a novel single cell electroporation biochip featuring high aspect ratio nickel micro-electrodes with smooth side walls between which individual cells are attached. The biochip is fabricated using Proton Beam Writing (PBW), a new direct write lithographic technique capable of fabricating high quality high-aspect-ratio nano and microstructures. By applying electrical impulses across the biochip electrodes, SYTOX® Green nucleic acid stain is incorporated into mouse neuroblastoma (N2a) cells and observed via green fluorescence when the stain binds with DNA inside the cell nucleus. Three parameters; electric field strength, pulse duration, and numbers of pulses have been investigated for the single cell electroporation process. The results indicate high transfection rates as well as cell viability of 82.1 and 86.7% respectively. This single cell electroporation system may represent a promising method for the introduction of a wide variety of fluorophores, nanoparticles, quantum dots, DNAs and proteins into cells.

No abstract

Proton beam writing (PBW) is a lithographic technique that utilizes MeV protons in a direct write mode to fabricate micro/nano features in suitable resist material (E.g PMMA, SU-8, silicon, Foturan). These micro/nano structures may be used in an electroplating step to yield robust metallic stamps/molds for the replication of the original and lends itself to the fabrication of micro/nano fluidic channels that are important components in devices such as biophotonic chips. Another feature of proton bombardment is its ability to induce an increase in refractive index along the ions path, in particular at the end of its range where there is substantial nuclear scattering. This allows PBW to directly write buried waveguides that can be accurately aligned with fluidic channels.Polydimethylsiloxane (PDMS) is an optically clear, biocompatible polymer that can be readily used with a mold (such as that created with PBW) and easily sealed so as to produce biophotonic chips containing micro/nano fluidic channels. This has lead us to favour PDMS as the base material for our work on the development of these biophotonic chips. The present work is concerned with the production of integrating channel waveguides in PDMS chips, so as to have a working device that may be used to detect fluorescently tagged biological samples. For this we have adopted two approaches, namely(1) directly embedding optical fibres in the polymer and (2) using PBW to directly write buried waveguides in the polymer.