Anti-SPR (aa 164-260) polyclonal antibody

In clinical chemistry, frequent monitoring of drug levels in patients has gained considerable importance because of the benefits of drug monitoring on human health, such as the avoidance of high risk of over dosage or increased therapeutic efficacy. In this work, we demonstrate that the drug doxycycline can act as an Au nanoparticle (doxy-AuNP) growth and capping agent to enhance the response of a surface plasmon resonance (SPR) biosensor for this drug. SPR analysis revealed the high sensitivity of doxy-AuNPs towards the detection of free doxycycline. More specifically, doxy-AuNPs bound with protease-activated receptor-1 (PAR-1) immobilized on the SPR sensing surface yield the response in SPR, which was enhanced following the addition of free doxy (analyte) to the solution of doxy-AuNPs. This biosensor allowed for doxycycline detection at concentrations as low as 7 pM. The study also examined the role of colloidal stability and growth of doxy-AuNPs in relation to the response-enhancement strategy based on doxy-AuNPs. Thus, the doxy-AuNPs-based SPR biosensor is an excellent platform for the detection of doxycycline and demonstrates a new biosensing scheme where the analyte can provide enhancement.

The 1.54 mu m emission of Er3+ ions embedded in a dichmic Cu nanocomposite glass is shown to be either quenched or enhanced depending on the excitation wavelength. The synthesized material consisted of an aluminphosphate matrix co-doped with Cu and Er as prepared by thermal processing, and characterized by optical absorption and photoluminescence (PL) spectroscopy including an assessment of decay dynamics. The extinction spectrum presented a broad surface plasmon resonance (SPR) band for Cu nanoparticles (NPs) around 588 nm, while the glass appeared to scatter red light but transmit blue, i.e. exhibiting dichroism. Interestingly, the PL obtained for the I-4(1)3/2 ->(4)I(15/2 )emission around 1.54 mu m was enhanced under the excitation of the I-4(15/2) -> F-4(912) transition at 650 nm, which turned out to be located toward the low energy wing of the SPR of Cu NPs. About a 12% PL boost was estimated relative to a merely Er3+ -doped reference. Conversely, a PL quenching effect was manifested for resonant Er3+ excitations (e.g. I-4(1)5/2 -> (2)H(11/2 )transition at 520 nm) overlaid with the 3d -> 4sp interband transitions absorption in copper. It is suggested that favorable conditions for the PL enhancement are achieved for when the excitation of Er3+ ions can benefit from light scattering by plasmonic Cu particles, while an excitation energy transfer from Er3+ to Cu NPs via interband transitions leads to the quenching.