DEVICE AND IN SITU METHOD PRODUCTION OF NANOPARTICLES FOR SURFACE-ENHANCED RAMAN SPECTROSCOPY IN A MOBILE MEASUREMENT STATION

Abstract

A device for the production of nanoparticles in situ for Surface-enhanced Raman spectroscopy in a mobile measurement station includes a least a first block having a control system, an automatic titration and dosing system, containers for substances with a system supplying substances to a reactor, a chemical reactor with a substance stirring system, sensors for controlling the nanomaterial production process, a heating and process temperature control system, a system for conducting the produced material to the next block outside, a nanoparticle processing system to perform measurements. A related method produces nanoparticles in situ for Surface-enhanced Raman spectroscopy in a mobile measurement station.

Claims

1.-6. (canceled)

7. A device for generation of nanoparticles in situ for Surface-enhanced Raman spectroscopy in a mobile measuring station, the device comprising: at least a first block including: a control system; an automatic titration and dosing system; a first set of containers for substances with a system for supplying substances to the reactor; a chemical reactor with a substance stirring system; sensors to control the nanomaterial production process; a heating and process temperature control system; a discharge system of the produced material to the next block outside; and a nanoparticle processing system for measurements.

8. The device according to claim 7, further comprising at least one additional block.

9. The device according to claim 7, further comprising a second block, the second block including: a second control system; a second automatic titration and dosing system; a second set of containers for substances with a system for supplying substances to the reactor; a second chemical reactor with a substance stirring system; second sensors to control the nanomaterial production process; a second heating and process temperature control system; a second discharge system of the produced material to the next block outside; and a second nanoparticle processing system for measurements.

10. The device according to claim 7, wherein the device includes a plurality of blocks with a common monitoring system.

11. A method of producing nanoparticles in situ for Surface-enhanced Raman spectroscopy in a mobile measuring station with the device of claim 7, the method comprising: automatically regulating an amount, concentration, moment, rate and time of adding appropriate chemicals to the containers with the control system, as well as the stirring rate and reaction time in the reactor; controlling the temperature of the solution with the heating system; and regulating the course of processes with the control system in response to feedback in the form of information from the sensor system about the parameters of nanoparticles obtained in the reaction, where the optical spectrum of the solution is recorded in the UV-VIS range (300-1100 nm) and optionally pH registration of nanoparticle solution, and optionally other nanoparticle parameters.

12. The method according to claim 11, wherein metallic, preferably silver, nanoparticles are produced in the first block.

13. The method according to claim 12, further comprising producing core-shell type nanoparticles in a second block, the core of which are metallic nanoparticles, preferably silver, transferred from the first block, and the coating is preferably made of gold or silica.

14. The method according to claim 11, wherein the produced nanoparticles are activated to perform measurements by Surface-enhanced Raman spectroscopy in the processing system, by centrifugation and decantation as well as intaking a concentrated solution of nanoparticles.

Description

DESCRIPTION OF THE FIGURES

[0032] FIG. 1—presents a diagram of the first part of the system, the composition of which consists of: (1) control system, (2) automatic titration and dosing system, (3, 4, 5) containers for substances with hoses leading to the reactor (respectively deionized water, precursor, reducer etc.), (6) chemical reactor (tank) with a magnetic stirring system of substances, (7) a set of sensors to control the nanomaterial production process, (8) heating and process temperature control system, (9) system discharging the produced material together with a discharge and supply hose to the next block/outside, (10) a nanoparticle processing system to perform the measurements.

[0033] FIG. 2—presents the absorbance of an exemplary nanoparticle solution made in stage I and an exemplary nanoparticle solution made in stage II.

[0034] The invention is illustrated by the following non-limiting example

EXAMPLE

[0035] The operation of the device is based on the production of nanoparticles inducing the effect of Surface-enhancement of Raman spectroscopy and the possibility of their activation to perform measurements in the place of the measured object. The device produces one type of nanoparticle in the first stage and then passes them to the second block where the second stage of producing nanoparticles is performed. In the first stage, silver nanoparticles are obtained, and in the second stage, they are covered with a gold coating.

[0036] The detailed operation of the device consists in: [0037] (I) preparing the manufacturing equipment by refilling the chemical tanks; [0038] (II) accurately measuring and applying the appropriate substances at the right moment and time to the first reactor (vessel) (6), including stirring control and heating (7) of the vessel (6) so as to produce nanoparticles in the first reaction stage; [0039] (III) transferring the nanomaterials produced in the first reaction step to the second vessel and carrying out the second reaction step by measuring and applying the appropriate substances at the appropriate moment and time, including controlling (1) strirring and heating (7) of the vessel (6). [0040] (IV) control of the entire process is achieved by reading information from sensors (7) by the electronics controlling the system; [0041] (V) storing the produced nanoparticles in a vessel for the finished nanoparticles; [0042] (VI) activation of nanoparticles (10) for measurements with the possibility of transferring them outside the system, e.g. to a mobile measurement station.

[0043] The chemicals used in the process are placed in appropriate containers.

[0044] The first stage of the process consists in the production of an aqueous colloid of silver nanoparticles of appropriate sizes, preferably from 40 to 60 nm in diameter, preferably spherical in shape. The production method consists in the synthesis of silver nuclei and then growing the nanoparticles from the nuclei to the desired size and shape.

[0045] The second stage of the process consists in creating a gold coating on the silver nanoparticles obtained in the first stage of the process. The thickness of the gold coating allows it to be adjusted to the required wavelength. Typically the required wavelength is equal to the wavelength of the most common lasers, e.g. 512 nm, 532 nm, 633 nm, 785 nm or 830 nm, preferably 785 nm.

[0046] The course of process control by the control system enables the usage of feedback information based on the sensor system, including sensors measuring the parameters of the produced nanoparticles. The measurement of the parameters of the produced nanoparticles can be based on the measurement of optical spectra in the range of 300 nm-1000 nm. For example, a white LED light source system and a photodiode array with an optical filter or a spectrometer can be used.

[0047] Performing measurements using the Surface-enhanced Raman spectroscopy requires prior activation of the nanomaterial. For this purpose, the nanoparticles produced in the last stage are subjected to the method of purification from reaction residues and removal of the agent that protects the nanoparticles which prevents their aggregation and contact with the analyte substance. Therefore, in the nanoparticle processing system (10) they are spun, in the range of 500-4000 rcf, preferably 2000 rcf, and then, as a heavier fraction, they are at the bottom. The nanoparticles collected from the bottom after centrifugation are ready for measurement.

LITERATURE

[0048] [1] Stiles, P. L., Dieringer, J. A., Shah, N. C. and Duyne, R. P. V., “Surface-Enhanced Raman Spectroscopy,” Annual Review of Analytical Chemistry 1(1), 601-626 (2008). [0049] [2] Mosier-Boss, P., “Review of SERS Substrates for Chemical Sensing,” Nanomaterials 7(6), 142 (2017). [0050] [3] Lal, S., Grady, N. K., Kundu, J., Levin, C. S., Lassiter, J. B. and Halas, N. J., “Tailoring plasmonic substrates for surface enhanced spectroscopies,” Chem. Soc. Rev. 37(5), 898-911 (2008). [0051] [4] Cialla, D., März, A., Böhme, R., Theil, F., Weber, K., Schmitt, M. and Popp, J., “Surface-enhanced Raman spectroscopy (SERS): progress and trends,” Anal Bioanal Chem 403(1), 27-54 (2012). [0052] [5] Lin, X.-M., Cui, Y., Xu, Y.-H., Ren, B. and Tian, Z.-Q., “Surface-enhanced Raman spectroscopy: substrate-related issues,” Anal Bioanal Chem 394(7), 1729-1745 (2009). [0053] [6] Rahaman, M. H. and Kemp, B. A., “Analytical model of plasmonic resonance from multiple core-shell nanoparticles,” Opt. Eng 56(12), 121903-121903 (2017). [0054] [7] Gupta, R., Siddhanta, S., Mettela, G., Chakraborty, S., Narayana, C. and Kulkarni, G. U., “Solution processed nanomanufacturing of SERS substrates with random Ag nanoholes exhibiting uniformly high enhancement factors,” RSC Adv. 5(103), 85019-85027 (2015). [0055] [8] Siddhanta, S., Wróbel, M. S. and Barman, I., “Integration of protein tethering in a rapid and label-free SERS screening platform for drugs of abuse,” Chem. Commun. 52(58), 9016-9019 (2016). [0056] [9] Stevenson, A. P., Blanco Bea, D., Civit, S., Antoranz Contera, S., Iglesias Cerveto, A. and Trigueros, S., “Three strategies to stabilise nearly monodispersed silver nanoparticles in aqueous solution,” Nanoscale Res Lett 7(1), 151 (2012). [0057] [10] Bastús, N. G., Merkoçi, F., Piella, J. and Puntes, V., “Synthesis of Highly Monodisperse Citrate-Stabilized Silver Nanoparticles of up to 200 nm: Kinetic Control and Catalytic Properties,” Chem. Mater. 26(9), 2836-2846 (2014). [0058] [11] Rycenga, M., Cobley, C. M., Zeng, J., Li, W., Moran, C. H., Zhang, Q., Qin, D. and Xia, Y., “Controlling the Synthesis and Assembly of Silver Nanostructures for Plasmonic Applications,” Chem. Rev. 111(6), 3669-3712 (2011).