Nanostructured gold substrates provide chemically stable, signal-enhancing substrates for the sensitive detection of a variety of compounds through surface-enhanced Raman spectroscopy (SERS). Recent ...developments in advanced fabrication methods have enabled the manufacture of SERS substrates with repeatable surface nanostructures that provide reproducible quantitative analysis, historically a weakness of the SERS technique. Here, we describe the novel use of gold-sputtered Blu-ray disc surfaces as SERS substrates. The unique surface features and composition of the Blu-ray disc recording surface lead to the formation of gold nano-islands and nanogaps following simple gold sputtering, without any background peaks from the substrate. The SERS performance of this substrate is strong and reproducible with an enhancement factor (EF) of 10
3
for melamine. A limit of detection (LOD) for this compound of 70 ppb and average reproducibility of ±12 % were achieved. Gold-sputtered Blu-ray discs thus offer an excellent alternative to more exotic gold SERS substrates prepared by advanced, time-consuming and expensive methods.
Graphical abstract
AFM 3D images of 1-μm
2
sections of uncoated and gold-sputtered recordable Blu-ray disc (BD-R) surfaces and the SERS signal obtained on the gold-sputtered surface for a 1000 ppm aqueous solution of melamine.
We demonstrate a surface plasmon resonance imaging platform integrated with a smartphone to be used in the field with high-throughput biodetection. Inexpensive and disposable SPR substrates are ...produced by metal coating of commercial Blu-ray discs. A compact imaging apparatus is fabricated using a 3D printer which allows taking SPR measurements from more than 20.000 individual pixels. Real-time bulk refractive index change measurements yield noise equivalent refractive index changes as low as 4.12×10−5 RIU which is comparable with the detection performance of commercial instruments. As a demonstration of a biological assay, we have shown capture of mouse IgG antibodies by immobilized layer of rabbit anti-mouse (RAM) IgG antibody with nanomolar level limit of detection. Our approach in miniaturization of SPR biosensing in a cost-effective manner could enable realization of portable SPR measurement systems and kits for point-of-care applications.
Significant improvements in video compression capability have been demonstrated with the introduction of the H.264/MPEG-4 advanced video coding (AVC) standard. Since developing this standard, the ...Joint Video Team of the ITU-T Video Coding Experts Group (VCEG) and the ISO/IEC Moving Picture Experts Group (MPEG) has also standardized an extension of that technology that is referred to as multiview video coding (MVC). MVC provides a compact representation for multiple views of a video scene, such as multiple synchronized video cameras. Stereo-paired video for 3-D viewing is an important special case of MVC. The standard enables inter-view prediction to improve compression capability, as well as supporting ordinary temporal and spatial prediction. It also supports backward compatibility with existing legacy systems by structuring the MVC bitstream to include a compatible "base view." Each other view is encoded at the same picture resolution as the base view. In recognition of its high-quality encoding capability and support for backward compatibility, the stereo high profile of the MVC extension was selected by the Blu-Ray Disc Association as the coding format for 3-D video with high-definition resolution. This paper provides an overview of the algorithmic design used for extending H.264/MPEG-4 AVC towards MVC. The basic approach of MVC for enabling inter-view prediction and view scalability in the context of H.264/MPEG-4 AVC is reviewed. Related supplemental enhancement information (SEI) metadata is also described. Various "frame compatible" approaches for support of stereo-view video as an alternative to MVC are also discussed. A summary of the coding performance achieved by MVC for both stereo- and multiview video is also provided. Future directions and challenges related to 3-D video are also briefly discussed.
•A portable holographic microscopy was developed using a Blu-Ray pickup•The Blu-Ray objective lens provided high quality phase images•The interferometer was fully controlled using a Raspberry-Pi ...computer•Three-wavelengths laser diode allow the study of different type of samples
The concept of point-of-care testing is an active area of research. The trend nowadays is to develop cost-effective yet efficient units that can be used at home by non-professionals. Digital holography is an optical technique of great interest as it provides quantitative phase images from a single recorded image. However, the available setups either employ the in-line lensless configuration (which involve an iterative phase recovery process) or the complex, bulky and expensive classical Mach-Zehnder configuration. Self-referencing digital holographic systems are ideal as only few components are needed. Blu-Ray pickup heads contain a high quality objective lens and a laser diode which have been used in the past in optical microscopy. However, it has been rarely uses in digital holography. In this paper, we present for the first time a low-cost self-referencing digital holography microscope in a transmission configuration using a Blu-Ray pickup coupled with a Raspberry-Pi computer, making the whole setup very compact. A low-cost 2D motorized translation stage is developed using the mechanical components found in the Blu-Ray drive. A Graphical User Interface (GUI) written in Python allows the user to control the hardware components and to reconstruct the holograms from which continuous phase images are extracted. The interferometer is successfully tested on microspheres and red blood cells after estimating the magnification of the microscope using a USAF target.
•Fully automated characterization platform for biopolymer degradation studies through micromechanical resonator based on Blu-Ray pick-up head unit is developed.•PLGA degradation study under ...Proteinase-K action.•Improved methodology embedding a microfluidic device for in flow biopolymer degradation studies.•Match of the degradation parameter with the conventional studies performed on bulky amount of samples and long experimental time frame.
Degradable biopolymers are used as carrier materials in drug delivery devices. A complete understanding of their degradation behaviour is thus crucial in the design of new delivery systems. Here we combine a reliable method, based on spray coated micromechanical resonators and a disposable microfluidic chip, to characterize biopolymer degradation under the action of enzymes in controlled flow condition. The sensing platform is based on the mechanics and optics from a Blu-Ray player, which automatically localize individual sensors within the array, and sequentially measure and record the resonance frequency of up to twelve resonators within 4min. Such fast and automated measuring technology, combined with the use of thin polymers layers in the degradation experiments, allows to reduce the experimental time needed for degradation studies from 6 weeks to 8h. We first present a full characterization of sensor properties and then perform degradation studies of poly(lactic-co-glycolic acid) (PLGA) in steady flow for three different enzyme concentrations. The degradation has been performed in liquid environment. Before each resonator measurement, the measuring chamber has been automatically dried, since the resonator characteristics are much approved when measuring in air compared to liquid. The obtained degradation profiles are comparable to profiles obtained by conventional approaches, which have shown to require up to 6 weeks of experimental time frame.
Nanostructure-based plasmonic biosensors have quickly positioned themselves as interesting candidates for the design of portable optical biosensor platforms considering the potential benefits they ...can offer in integration, miniaturization, multiplexing, and real-time label-free detection. We have developed a simple integrated nanoplasmonic sensor taking advantage of the periodic nanostructured array of commercial Blu-ray discs. Sensors with two gold film thicknesses (50 and 100nm) were fabricated and optically characterized by varying the oblique-angle of the incident light in optical reflectance measurements. Contrary to the use normal light incidence previously reported with other optical discs, we observed an enhancement in sensitivity and a narrowing of the resonant linewidths as the light incidence angle was increased, which could be related to the generation of Fano resonant modes. The new sensors achieve a figure of merit (FOM) up to 35 RIU−1 and a competitive bulk limit of detection (LOD) of 6.3×10−6 RIU. These values significantly improve previously reported results obtained with normal light incidence reflectance measurements using similar structures. The sensor has been combined with versatile, simple, ease to-fabricate microfluidics. The integrated chip is only 1cm2 (including a PDMS flow cell with a 50µm height microfluidic channel fabricated with double-sided adhesive tape) and all the optical components are mounted on a 10cm×10cm portable prototype, illustrating its facile miniaturization, integration and potential portability. Finally, to assess the label-free biosensing capability of the new sensor, we have evaluated the presence of specific antibodies against the GTF2b protein, a tumor-associate antigen (TAA) related to colorectal cancer. We have achieved a LOD in the pM order and have assessed the feasibility of directly measuring biological samples such as human serum.
•An integrated nanostructured plasmonic biosensor based on Blu-ray disc is proposed.•A performance enhancement at high angles of incidence light is observed.•A figure of merit (FOM) up to 35 RIU−1 and a LOD of 6.34×10−6 RIU is reached.•Detection of antibodies related to colorectal cancer is achieved at the pM level.
The potential and the capabilities of Blu-ray technology (discs and drives) for massive screening applications are presented. High density microarrays are fabricated onto a Blu-ray disc and applied ...for the determination of microcystin residues and pathogenic microorganisms. Specific probes were physisorbed onto the BD surface and the biorecognition event was displayed using labeled secondary antibody solution and subsequent signal amplification. The attenuation of the reflected light caused by the reaction product is detected by the Blu-ray drive and inversely correlated with analyte concentration.
BDs preserve the optical properties according to Blu-ray specifications, ensuring maximum accuracy and sensitivity of the drive during disc scanning. Detection limits of 0.4μg/L for microcystin LR and 100 and 101cfu/mL for Salmonella typhimurium and Cronobacter sakazakii respectively, were achieved, improving considerably the DVD performances and reaching similar sensitivity as real-time quantitative PCR. Blu-ray technology adapted to the analysis of high density arrays highlights the enormous capabilities (high sensitivity, speed-scanning, optical resolution, portability) for point-of-care settings, diagnostics, and high-throughput screening applications.
•Blu-ray discs offer unique properties for physisoprtion of probes, eliminating the need of chemical activation of the surface.•The reduced background noise of BD discs allows the development of high density microarrays with increased sensitivity and utility.•Blu-ray technology provides advanced capabilities to perform high-density microarray analysis and suits well for low-level labs or outside the lab setting.
One-dimensional photonic crystal slabs are periodic optical nanostructures that produce guided-mode resonance. They couple part of the incident light into the waveguide generating bandgaps in the ...transmittance spectrum, whose position is sensitive to refractive index variations on their surface. In this study, we present one-dimensional photonic crystal slab biosensors based on the internal nanogrooved structure of Blu-ray disks for label-free immunosensing. We demonstrated that this polycarbonate structure coated with a critical thickness of TiO2 generates guided-mode resonance. Its optical behavior was established comparing it with other compact disk structures. The results were theoretically calculated and experimentally demonstrated, all them being in agreement. The bioanalytical performance of these photonic crystals was experimentally demonstrated in a model assay to quantify IgGs as well as in two immunoassays to determine the biomarkers C-reactive protein and lactate dehydrogenase (detection limits of 0.1, 87, and 13 nM, respectively). The results are promising towards the development of new low-cost, portable, and label-free optical biosensors that join these photonic crystals with dedicated bioanalytical scanners based on compact disk drives.
•One-dimension photonic crystal slabs based on Blu-ray disks coated with a thin layer of TiO2.•Guided-mode resonance behavior simulated and experimentally characterized.•An experimental sensitivity of 28 nm RIU−1 in bulk.•Sensitive and selective quantification of IgG, CRP, and LDH in label-free conditions.
•The use of blu-ray DVD (BRDVD) as a SERS substrate has been presented.•Colloidal gold nanoparticles has been treated with BRDVD to obtain the proposed SERS substrate.•Waveguiding nature of BRDVD ...nanochannel has been exploited to obtain guided mode resonance for coupled electromagnetic field with the substrate.•The substrate has been used for detection of fluorescent and non-fluorescent Raman active samples.•The usability of the SERS substrate for detection and quantification of clinically important chemicals has been demonstrated.
We report here the working of a simple reproducible surface enhanced Raman scattering (SERS) substrate by efficiently guiding localized plasmon resonance (LSPR) field of gold nanoparticles (AuNPs) through trapping it in the nano channels of a blu-ray digital versatile disc (BRDVD). SERS based sensing of the designed substrate has been performed. The trapped AuNPs in the channel of the BRDVD generate guided mode resonance (GMR) field and the photon lifetime of the coupled em field in the channel increases which accounts for overall enhancement of the local field intensity. These two factors are primarily responsible for enhancement of the scattered Raman signal from the substrate. The proposed SERS substrate yields reasonably stable signal intensity over a period of 45 days. With the designed substrate Raman signal intensities of three clinically important chemicals namely albumin, creatinine and urea in urine have been measured and quantified reliably. The minimum concentration of albumin, creatinine and urea which can be measured by Raman spectrometer are 0.1 μg/mL, 0.2 μg/mL and 0.6 μg/mL respectively. These values are well below the normal range and thus meet the requirement of detection and analysis of these chemicals for different clinical purposes.
We have developed large-scale one-dimensional photonic crystals from standard recordable Blu-ray disks, tailored to sense unlabeled biorecognition events on their surface. These materials rely on ...coating, with layers of 80 nm of titanium oxide, nanogrooved polycarbonate plates obtained from regular disks. As a result, they present guided-mode resonances that we have demonstrated that can be exploited to quantify biorecognition events by means of the bandgap positions in the transmission spectra. These photonic crystals have displayed well-correlated dose-response curves in immunoassays to quantify IgGs, C-reactive protein, and lactate dehydrogenase. The detection limit reached is 16 ng/mL, 2μg/mL, and 18 ng/mL, respectively. Herein we describe the experimental procedures and methods to fabricate and functionalize these photonic crystals, perform immunoassays on them, set up an optical system to measure their response, and process the resulting data to perform bioanalytical determinations in label-free format.
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