title: Enhancing surface enhanced Raman scattering (SERS) detection of propranolol with multiobjective evolutionary optimization.
abstract: Colloidal-based surface-enhanced Raman scattering (SERS) is a complex technique, where interaction between multiple parameters, such as colloid type, its concentration, and aggregating agent, is poorly understood. As a result SERS has so far achieved limited reproducibility. Therefore the aim of this study was to improve enhancement and reproducibility in SERS, and to achieve this, we have developed a multiobjective evolutionary algorithm (MOEA) based on Pareto optimality. In this MOEA approach, we tested a combination of five different colloids with six different aggregating agents, and a wide range of concentrations for both were explored; in addition we included in the optimization process three laser excitation wavelengths. For this optimization of experimental conditions for SERS, we chose the β-adrenergic blocker drug propranolol as the target analyte. The objective functions chosen suitable for this multiobjective problem were the ratio between the full width at half-maximum and the half-maximum intensity for enhancement and correlation coefficient for reproducibility. To analyze a full search of all the experimental conditions, 7785 experiments would have to be performed empirically; however, we demonstrated the search for acceptable experimental conditions of SERS can be achieved using only 4% of these possible experiments. The MOEA identified several experimental conditions for each objective which allowed a limit of detection of 2.36 ng/mL (7.97 nM) propranolol, and this is significantly lower (>25 times) than previous SERS studies aimed at detecting this β-blocker.
authors.affiliation: Faculty of Life Sciences, Manchester Institute of Biotechnology, University of Manchester, UK.
authors.forename: Clare
authors.initials: C
authors.lastname: Levene
authors.forename: Elon
authors.initials: E
authors.lastname: Correa
authors.forename: Ewan W
authors.initials: EW
authors.lastname: Blanch
authors.forename: Royston
authors.initials: R
authors.lastname: Goodacre
mesh_terms: D000465:Algorithms; D003102:Colloids / Q000737:chemistry; D007834:Lasers; D011433:Propranolol / Q000032:analysis*; D013059:Spectrum Analysis, Raman
chemical_list: D003102:Colloids; D011433:Propranolol