The simplification of localized surface plasmon resonance (LSPR) detection can further promote the development of optical biosensing application in point-of-care testing. In this study, we proposed a simple light emitting diode (LED) based single-wavelength LSPR sensor modulated with bio-electron transfers for the detection of electroactive biomolecules. Indium tin oxide electrode loaded with nanocomposites of polyaniline coated gold nanorod was used as LSPR chip, and the applied electric potential was scanned at the LSPR chip for single-wavelength LSPR biosensing. Under the scanning of applied potentials, biological electron transfer of redox reaction was employed to demonstrate the bioelectronic modulation of single-wavelength LSPR for selective electroactive biomolecule detection. Without any additional recognition material, electroactive biomolecules uric acid and dopamine were detected directly with a sensitivity of 5.05 μmol/L and 7.11 μmol/L at their specific oxidation potentials, respectively. With the simplified optical configuration and selective bioelectronic modulation, the single-wavelength LSPR sensor is promising for the development of simple, low-cost, and high specificity optical biosensor for point-of-care testing of electroactive biomolecules. 相似文献
We demonstrate seedless synthesis of gold nanorods at high temperatures up to 97 degrees C. Using the correct silver nitrate concentration is crucial for formation of rod-shaped particles at all temperatures. We observed a decrease of nanorod length with increasing temperature, while the width stays constant throughout the temperature range. From kinetics studies, we show 3 orders of magnitude increase in nanorod growth rate when the temperature is raised from room temperature to 97 degrees C. From the temperature dependence of the growth rate, we obtain a average activation energy for growth on all facets of 90 +/- 10 kJ mol(-1). High-temperature synthesis of gold nanorods presents a more attractive method for scalable flow-based production of gold nanorods. 相似文献
We report on an effective strategy for the enhancement in the sensitivity of localized surface plasmon resonance (LSPR). It is based on the use of gold-silver core-shell nanorods (Au-Ag-cs-NRs) immobilized on a glass substrate. The nanorods arrange themselves by self-assembly, and the resulting LSPR band of the Au-Ag-cs-NRs becomes sharper and more intense. The sensitivity to refractive index (RI) of the Au-Ag-cs-NRs on the glass support is ~281 nm per RI unit, which is better by about 30 % compared to gold nanorods immobilized on glass substrate. The system was applied to study the streptavidin-biotin affinity system which is widely used in biosciences. It is found that the red-shift of the LSPR peak linearly increases with the concentration of streptavidin in the 95 pM to 1.7 μM concentration range. The detection limit (at an S/N ratio of 3) is at 35 pM. The results reveal the merits of this approach in terms of label-free optical affinity sensing.
Au-Ag core-shell nanorods self-assembled on glass substrates. The refractive index sensitivity was enhanced obviously. A strategy to amplify the response and fabricate a label-free optical biosensor