In addition, the shell can also bring the following merits: (1) hinders the Ag NPs from the medium that could produce the noise (2) provides a convenient functionalized surface for coupling the other molecules 2.Įncapsulating silica on the NPs suface demands that the NPs are stable in alcohol solution before the hydrolysis/condensation of tetraethyl orthosilicate (TEOS). For their applications, a general approach is to coat a silica shell to overcome the above shortcomings. However, such SERS tags are unstable under the ambient conditions, oxidation in the air, aggregation in salt solution and dissociation of Raman molecules, particularly, biotoxicity to limit their applications 2, 17. Among them, citrate-capping Ag NPs are expected to be an ideal candidate for SERS studies, because citrate groups as the much weaker capping agents on the NP surface, are easily exchanged with Raman reporter molecules to ensure the intimate contact between the Raman moleules and Ag NPs 16. In SERS nano-tags, Ag NPs have been proven to be the best substrates for SERS analysis. Therefore, SERS nano-tags are under more and more active investigation for in vivo applications 7, 8, 9, 10. no photobleaching and the much more number of distinct signals in the NIR window. Importantly, as NIR optical probe, SERS nano-tags overcome the shortcomings of the other NIR probes, e.g. QDs and fluorescent dyes, SERS tags are superior in multiplexing, ultra-sensitivity, high-photostability and quantitative abilities 2, 13, 14, 15. Such SERS tags possess strong Raman signals from the Raman molecules and can be employed to inderectly recognize the target molecules, presenting labeling functions same with the fluorophores such as organic dyes and quantum dots (QDs) 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13. In the present, this technique has been employed to construct new nanoprobes (named as SERS nano-tags) that merge noble metallic nanoparticles (NPs) with Raman molecules 2. Surface-enhanced Raman scattering (SERS) is a highly-sensitive vibrational spectroscopy technique to detect analytes on or near the surface of plasmon nanostructures, greatly expanding the role of Raman spectroscopy 1. Moreover, this kind of SERS tags coated with silica hold the stronger SERS signals than the traditional method due to no interference from the priming molecules. This approach is highly reproducible for silica shell growth and signal intensity, not depending on the properties of Raman molecules, proved by 7 kinds of the Raman molecules. Based on this, the Ag SERS tags can be directly coated with thickness-controlled and homogeneous silica shells.
By decreasing the concentration of salt in Ag NP solution, the citrate-stabilized Ag NPs can be well dispersed in alcohol solution. This approach mainly depends on the colloidal stability of the Ag NPs in alcohol solution. Here, we report a facile and general method to prepare the silica-coated Ag SERS tags with the enhanced signal intensity by no introducing the primers. However, the reported methods to synthesize these tags are tedious and often subjected to the limited signal intensity.
#Signal peak silica plus#
False air can shorten the life of the baghouse and its wear components, plus shorten the life of the ID fan by wear due to increased material contact at a higher suction velocity.Silica-coated SERS tags have been attracting greater attention in recent years. Plattco’s Double Flap Airlock Valve reduced tramp/false air that would otherwise make it into the baghouse system.Plattco’s Airlock extends ID fan life by reducing the amount of particulate that makes its way back to the ID fan from tramp/false air leakage.Plattco’s proven Airlock decreases ID fan consumption by reducing the amount of electrical consumption needed for the ID fan to maintain its vacuum for the baghouses.This allows the intended “discharge” material to drop down to the Plattco valve and be conveyed. Plattco’s Airlock valves extend baghouse life by extending the life of the filters situated inside the compartment of the baghouse.In turn, this allows the conveyance of heavier particulates to drop and discharge at its hopper outlet below. Our Airlock technology improves baghouse efficiency by maintaining the integrity of the internal vacuum pressure of the baghouse.
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