ABSTRACT
Surface plasmon resonance (SPR) is a label-free, real-time bio-sensing technique with high potential in the diagnostic area, especially when a signal amplification strategy is used to improve the detection limit. We report here a simple method for enhancing the detection limit of bovine serum albumin (BSA), by attaching gold nanorods (AuNRs). AuNRs were obtained by a seedless synthesis technique and characterized using scanning electron microscopy (SEM), UV-VIS spectroscopy, FT-IR spectroscopy and dynamic light scattering (DLS). Finite element method (FEM) simulations were employed to explore the enhancement of the SPR signal by adding AuNRs on the SPR sensor's metallic layer. SPR spectroscopy was used to analyze the changes in the refractive index brought by the immobilization of unconjugated BSA and BSA modified with AuNRs. The results confirmed that the AuNRs conjugated with the protein increase the SPR signal ~ 10 times, leading to a limit of detection of 1.081 × 10-8 M (0.713 µg/mL).
Subject(s)
Biosensing Techniques , Nanotubes , Biosensing Techniques/methods , Gold/chemistry , Nanotubes/chemistry , Serum Albumin, Bovine/chemistry , Spectroscopy, Fourier Transform Infrared , Surface Plasmon ResonanceABSTRACT
Two protoporphyrin IX (PpIX) adamantane derivatives were synthesized and then metallated with zinc. The Zn-PpIX derivatives, exhibiting a high singlet oxygen quantum yield, were tested for their photodynamic activity against the HT-29 cell line. In order to enhance their water-solubility and their cellular bioavailability, these photosensitizers were encapsulated into the hydrophobic cavity of cyclodextrins (CD) previously attached to cellulose nanocrystals (CNCs) via electrostatic interactions. Under illumination, the encapsulated adamantanyl-porphyrins exerted an enhanced in vitro cytotoxicity, as compared with the corresponding free photosensitizers.
Subject(s)
Adamantane/pharmacology , Antineoplastic Agents/pharmacology , Cellulose/pharmacology , Cyclodextrins/pharmacology , Photochemotherapy , Photosensitizing Agents/pharmacology , Protoporphyrins/pharmacology , Adamantane/chemistry , Antineoplastic Agents/chemical synthesis , Antineoplastic Agents/chemistry , Cell Proliferation/drug effects , Cell Survival/drug effects , Cellulose/chemistry , Cyclodextrins/chemistry , Dose-Response Relationship, Drug , Drug Design , Drug Screening Assays, Antitumor , HT29 Cells , Humans , Molecular Structure , Nanoparticles/chemistry , Photosensitizing Agents/chemical synthesis , Photosensitizing Agents/chemistry , Protoporphyrins/chemistry , Structure-Activity RelationshipABSTRACT
The main goal of this paper is to give some primal and dual Karush-Kuhn-Tucker second-order necessary conditions for the existence of a strict local Pareto minimum of order two for an inequality-constrained multiobjective optimization problem. Dual Karush-Kuhn-Tucker second-order sufficient conditions are provided too. We suppose that the objective function and the active inequality constraints are only locally Lipschitz in the primal necessary conditions and only strictly differentiable in sense of Clarke at the extremum point in the dual conditions. Examples illustrate the applicability of the obtained results.
