Optimizing Blue Persistent Luminescence in (Sr_1−δBa_δ)₂MgSi₂O_7:Eu²⁺,Dy³⁺ via Solid Solution for Use in Point-of-Care Diagnostics

Inorganic persistent luminescent phosphors are an excellent class of optical reporters for enabling sensitive point-of-care diagnostics, particularly with smartphone-based biosensing devices in testing formats such as the lateral flow assay (LFA). Here, the development of persistent phosphors for this application is focused on the solid solution (Sr_1−δBa_δ)₂MgSi₂O₇:Eu²⁺,Dy³⁺ (δ = 0, 0.125, 0.25, 0.375), which is prepared using a high-temperature solid-state reaction as confirmed by synchrotron X-ray powder diffraction. The substitution of barium for strontium enables control over the Eu²⁺ 5d-orbital crystal field splitting (CFS) as a tool for tuning the emission wavelength while maintaining luminescence lifetimes >9 min across the composition range. Thermoluminescence measurements of the solid solution provide evidence that trap states contribute to the persistent lifetimes with the trap depths also remaining constant as a function of composition. Time-gated luminescence images of these compounds are captured on a smartphone arranged in a layout to mimic a point-of-care test and demonstrate the viability of using these materials as optical reporters. Moreover, comparing the blue-emitting (Sr_0.625Ba_0.375)₂MgSi₂O_7:Eu²⁺,Dy³⁺ and the green-emitting SrAl₂O₄:Eu²⁺,Dy³⁺ in a single LFA-type format shows these two compounds can be detected and resolved simultaneously, thereby permitting the development of a multiplexed LFA

AtwaterEtAl2015EcographyData

This .zip file contains the data used for this paper, along with a ReadMe file describing each data set

Additional file 3: of Gene duplication and evolution in recurring polyploidization–diploidization cycles in plants

The absolute number of different modes of duplicate gene pairs in each taxon. (XLSX 49 kb

Additional file 5: of Gene duplication and evolution in recurring polyploidization–diploidization cycles in plants

The enriched GO terms for tandem and proximal duplicate genes in Arabidopsis thaliana. (XLSX 69 kb

Additional file 6: of Gene duplication and evolution in recurring polyploidization–diploidization cycles in plants

The list of all RNA-Seq samples collected from different plants investigated in this study. (XLSX 105 kb

Additional file 4: of Gene duplication and evolution in recurring polyploidization–diploidization cycles in plants

The fitted Ks peak for WGD genes in each species. (XLSX 62 kb

Transmissive Nanohole Arrays for Massively-Parallel Optical Biosensing

A high-throughput optical biosensing technique is proposed and demonstrated. This hybrid technique combines optical transmission of nanoholes with colorimetric silver staining. The size and spacing of the nanoholes are chosen so that individual nanoholes can be independently resolved in massive parallel using an ordinary transmission optical microscope, and, in place of determining a spectral shift, the brightness of each nanohole is recorded to greatly simplify the readout. Each nanohole then acts as an independent sensor, and the blocking of nanohole optical transmission by enzymatic silver staining defines the specific detection of a biological agent. Nearly 10000 nanoholes can be simultaneously monitored under the field of view of a typical microscope. As an initial proof of concept, biotinylated lysozyme (biotin-HEL) was used as a model analyte, giving a detection limit as low as 0.1 ng/mL

Additional file 8: of Gene duplication and evolution in recurring polyploidization–diploidization cycles in plants

The enriched GO terms for the most-preserved, intermediate-preserved and least-preserved gene families in 141 plants. (XLSX 1018 kb

Additional file 1: of Gene duplication and evolution in recurring polyploidization–diploidization cycles in plants

Supplementary Table S1 and Figure S1-21. (DOCX 5373 kb

Additional file 7: of Gene duplication and evolution in recurring polyploidization–diploidization cycles in plants

The 232 most conserved gene families in 141 plants. (XLSX 1968 kb