A low cost photonic biosensor built on a polymer platform (original) (raw)
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A Label-Free Optical Biosensor Built on a Low-Cost Polymer Platform
IEEE Photonics Journal, 2012
Planar integrated optical biosensors are becoming more and more important as they facilitate label-free and real-time monitoring with high sensitivity. In this paper, the systematic work on the development of this kind of optical biosensor built on a novel polymer platform named PSQ-Ls will be presented. The material itself is of very low cost, and the optical devices with high performances are fabricated through a simple UV-based soft imprint lithography technique. Especially for ring resonator, Q value as high as 5 × 104 and 2.7 × 104 are achieved in air and water condition. These optical chips are functionalized efficiently with protein A molecules through physical immobilization, after careful investigation of the physicochemical and chemical properties of their surface. Both bulk sensing and surface sensing are performed. The proposed optical biosensor exhibits good response not only to its surrounding environment's change but also to the small amount of targeted molecules appearing in the buffered solution, which is human-IgG in our study.
Biosensors and Bioelectronics, 2009
Label-free monitoring of biomolecular interactions has become of key importance for the emerging proteomics field. Monitoring real time interaction kinetics and high throughput screening of complex samples is of major importance for a variety of applications. We previously reported the use of Silicon-on-Insulator photonics microring resonators for cheap disposable biosensors on chip. Silicon photonics is a platform for micro-and nanoscale integrated devices that can be fabricated at extremely low cost, with standard CMOS processing facilities. Incorporation of a hydrophilic heterobifunctional polymer coating on the silicon chips largely improved the system's response to non-specific binding. We report the chemical coating procedure, the chemical surface characterization and optical measurements for both specific and non-specific interactions. Two heterobifunctional polymer coatings were investigated, ␣-sulfanyl-carboxy-poly(ethylene glycol) and monoprotected diamino-poly(ethylene glycol). Homogenous coatings with thicknesses of 2.3 and 2.5 nm were obtained, corresponding to a surface loading of 99 pm/cm 2 carboxy-and 97 pm/cm 2 aminogroups, respectively. The polymer coated sensor with covalently bound biotin receptor molecules showed very low response to Bovine Serum Albumin (BSA) up to 1 mg/ml in contrast to a high response to avidin with much lower concentrations (2, 10, 87.5 and 175 g/ml). By extrapolation the detection limit is about 10 ng/ml or 0.37 fg avidin mass. Comparison with the values reported for standard silanization confirms the polymer coating does not deteriorate the system's limit of detection. This makes the optical biosensor chip suitable to be integrated in a microflow system for commercial label-free biosensors and for lab-on-a-chip applications.
Tagungsband, 2012
With optical biosensors based on planar optical waveguides, much progress was achieved in the last decade. Due to their high sensitivity, small size and good ability for integration, waveguides of microring resonator shape were identified to be especially suited for biosensor applications. Biosensing with microring resonators is typically carried out with reliable but bulky lab tools. Sensors are typically not integrated in portable sensor systems with a microfluidic system, laser source, detector as well as grating couplers. For point-of-care testing (POCT), these peripheral components are essential for an independent system usage. The biosensor system proposed in this work is based on a sensor chip with functional, polymeric microring resonators. With multilevel grating couplers, a miniaturized microfluidic system and cost-efficient UV-based nanoimprint (UV-NIL) manufacturing technology, the biosensor system has a high potential for further miniaturization and the use for POCT. The main focus in this work is the integration of a microfluidic system that allows the supply with analyte solutions and the processing of automated biosensor experiments. The influence of the microfluidic system on the sensing performance is discussed.
Micro-resonators based on integrated polymer technology for optical sensing
Optical Sensing and Detection III, 2014
Research on sensors has experienced a noticeable development over the last decades especially in label free optical biosensors. However, compact sensors without markers for rapid, reliable and inexpensive detection of various substances induces a significant research of new technological solutions. The context of this work is the development of a sensor based on easily integrated and inexpensive micro-resonator (MR) component in integrated optics, highly sensitive and selective mainly in the areas of health and food. In this work, we take advantage of our previous studies on filters based on micro-resonators (MR) to experiment a new couple of polymers in the objective to use MR as a sensing function. MRs have been fabricated by processing SU8 polymer as core and PMATRIFE polymer as cladding layer of the waveguide. The refractive index contrast reaches 0.16 @ 1550 nm. Sub-micronic ring waveguides gaps from 0.5 to 1 µm have been successfully achieved with UV (i-line) photolithography. This work confirms our forecasts, published earlier, about the resolution that can be achieved. First results show a good extinction coefficient of ~17 dB, a quality factor around 10 4 and a finesse of 12. These results are in concordance with the theoretical study and they allow us to validate our technology with this couple of polymers. Work is going on with others lower cladding materials that will be used to further increase refractive index contrast for sensing applications.
Integrated polymer micro-ring resonators for optical sensing applications
Journal of Applied Physics, 2015
Micro-resonators (MR) have become a key element for integrated optical sensors due to their integration capability and their easy fabrication with low cost polymer materials. Nowadays, there is a growing need on MRs as highly sensitive and selective functions especially in the areas of food and health. The context of this work is to implement and study integrated micro-ring resonators devoted to sensing applications. They are fabricated by processing SU8 polymer as core layer and PMATRIFE polymer as lower cladding layer. The refractive index of the polymers and of the waveguide structure as a function of the wavelength are presented. Using these results, a theoretical study of the coupling between ring and straight waveguides has been undertaken in order to define the MR design. Sub-micronic gaps of 0.5 µm to 1 µm between the ring and the straight waveguides have been successfully achieved with UV (i-lines) photolithography. Different superstrates such as air, water and aqueous solutions with glucose at different concentrations have been studied. First results show a good normalized transmission contrast of 0.98, a resonator quality factor around 1.5x10 4 corresponding to a coupling ratio of 14.7 % and ring propagation losses around 5 dB/cm. Preliminary sensing experiments have been performed for different concentrations of glucose; a sensitivity of 115 ± 8 nm/RIU at 1550 nm has been obtained with this couple of polymers.
Highly sensitive biosensor based on UV-imprinted layered polymeric–inorganic composite waveguides
Optics Express, 2012
An evanescent field sensor utilizing layered polymeric-inorganic composite waveguide configuration was developed in this work. The composite waveguide structure consists of a UV-imprint patterned polymer inverted rib waveguide with a Ta 2 O 5 thin film sputter-deposited on top of the low refractive index polymer layers. The results suggest that the polymer based sensor can achieve a detection limit of 3 × 10 −7 RIU for refractive index sensing and corresponding limit of about 100 fg/mm 2 for molecular adsorption detection. Besides enhancing the sensitivity significantly, the inorganic coating on the polymer layer was found to block water absorption effectively into the waveguide resulting in a stabilized sensor operation. The ability to use the developed sensor in specific molecular detection was confirmed by investigating antibody -antigen binding reactions. The results of this work demonstrate that high performance sensing capability can be obtained with the developed composite waveguide sensor.
A universal biosensing platform based on optical micro-ring resonators
Biosensors and Bioelectronics, 2008
The use of optical micro-ring resonators as a platform for quantitative and qualitative biosensing applications was explored. Vertically coupled, high refractive index micro-ring resonators, used as sensing elements, were fabricated on silicon chips by photolithographic techniques. An optical reader system consisting of a near-infrared broad band light source and an optical spectrum analyzer were employed for data acquisition. Micro-ring resonator surfaces were modified with specific target receptors, including antibodies and single-stranded DNA oligonucleotides. The system was successfully used for label-free, specific, and rapid detection of whole bacterial cells, proteins and nucleic acids.
High sensitivity optical biosensor based on polymer materials and using the Vernier effect
Optics Express
We demonstrate the fabrication of a Vernier effect SU8/PMATRIFE polymer optical biosensor with high homogeneous sensitivity using a standard photolithography process. The sensor is based on one micro-resonator embedded on each arm of a Mach-Zehnder interferometer. Measurements are based on the refractive index variation of the optical waveguide superstrate with different concentrations of glucose solutions. The sensitivity of the sensor has been measured as 17558 nm/RIU and the limit of detection has been estimated to 1.1.10-6 RIU.
IEEE Journal of Selected Topics in Quantum Electronics, 2010
A platform for performing rapid, real-time binding assays on sensor arrays based on silicon ring resonators is presented in this paper. An array of 32 sensors is interrogated simultaneously. Using eight sensors as controls, 24 simultaneous binding curves are produced. The bulk refractive index sensitivity of the system was demonstrated down to 7.6 × 10 −7 and sensor-to-sensor variability is 3.9%. Using an 8-min incubation, real-time binding was observed over 8-logs of concentration down to 60 fM using immobilized biotin to capture streptavidin diluted in bovine serum albumin solution. Multiplexing in complex media is demonstrated with two DNA oligonucleotide probes. Time to result and repeatability are demonstrated to be adequate for clinical applications.