Background: Parasite concentration methods facilitate molecular, biochemical and immunological research on the erythrocytic stages of Plasmodium. In this paper, an adaptation of magnetic MACS ® columns for the purification of human Plasmodium species is presented. This method was useful for the concentration/purification of either schizonts or gametocytes.

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We report, for the first time, the use of a surface plasmon resonance (SPR) fiber-optic immunosensor for selective cellular detection through membrane protein targeting. The sensor architecture lies on gold-coated tilted fiber Bragg gratings (Au-coated TFBGs) photoimprinted in the fiber core via a laser technique. TFBGs operate in the near-infrared wavelength range at ∼1550 nm, yielding optical and SPR sensing characteristics that are advantageous for the analyses of cellular bindings and technical compatibility with relatively low-cost telecommunication-grade measurement devices. In this work, we take consider their numerous assets to figure out their ability to selectively detect intact epithelial cells as analytes in cell suspensions in the range of 2-5 × 10(6) cells mL(-1). For this, the probe was first thermally annealed to ensure a strong adhesion of the metallic coating to the fiber surface. Its surface was then functionalized with specific monoclonal antibodies via alkanethiol self-assembled monolayers (SAMs) against extracellular domain of epidermal growth factor receptors (EGFRs) and characterized by peak force tapping atomic force microscopy. A differential diagnosis has been demonstrated between two model systems. The developed immunosensors were able to monitor, in real time, the specific attachment of single intact cells in concentrations from 3 × 10(6) cells mL(-1). Such results confirm that the developed probe fits the lab-on-fiber technology and has the potential to be used as a disposable device for in situ and real-time clinical diagnosis.

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In the context of plasmonic sensing using optical fibers, the controlled deposition of thin metal films remains a challenge, especially because of their cylindrical shape. In this work, we study the gold electroless plating (ELP), which is a direct and cost-effective technique to improve the quality and reproducibility of the metal deposition. In this paper, we use optical fibers to monitor the deposition process in real time. Our analysis is conducted on gratings photo-imprinted in the fiber core. Using polarized light, we show how the comb-like amplitude spectra of tilted fiber Bragg gratings (TFBGs) evolve depending on the ELP duration. This spectral evolution linked to a thorough study of the metal surface allows us to define the optimized process for improved surface refractometry. We experimentally show that this happens for a particular arrangement of gold nanoparticles yielding spectral features comparable to those obtained for localized surface plasmon resonance (LSPR) excitation. Biosensing experiments were performed and a LOD of 1 ng/mL (14 pM) is reported. This comes along with an enhanced specificity, contrasting with a poor sensitivity to bulk refractive index. All this is paving the way to a fast online coating procedure for nano-scaled and label-free biosensing using optical fibers.