The Effect of the Physical Morphology of Dried Biofluids on the Chemical Stability of Analytes Stored in Paper and Direct Analysis by Mass Spectrometry.

Three-dimensional (3D) dried blood spheroids formed on hydrophobic paper are a new microsampling platform that can stabilize labile molecules in whole blood stored in ambient air at room temperature. In this study, we define the ideal conditions for preparing the dried blood spheroids. The physical morphology of 3D dried blood spheroids is found to be largely impacted by the unregulated relative humidity of the surrounding environment.

Sensitive screening of single nucleotide polymorphisms in cell free DNA for diagnosis of gestational tumours.

Tumours expressing human chorionic gonadotropin (hCG), the majority of which are difficult to biopsy due to their vascularity, have disparate prognoses depending on their origin. As optimal management relies on accurate diagnosis, we aimed to develop a sensitive cell free DNA (cfDNA) assay to non-invasively distinguish between cases of gestational and non-gestational origin. Deep error-corrected Illumina sequencing of 195 common single nucleotide polymorphisms (SNPs) in cfDNA and matched genomic DNA from 36 patients with hCG-secreting tumours (serum hCG 5 to 3,042,881 IU/L) and 7 controls with normal hCG levels (≤4 IU/L) was performed.

Protective mechanism of dried blood spheroids: stabilization of labile analytes in whole blood, plasma, and serum.

Three-dimensional (3D) dried blood spheroids form when whole blood is deposited onto hydrophobic paper and allowed to dry in ambient air. The adsorbed 3D dried blood spheroid present at the surface of the hydrophobic paper is observed to offer enhanced stability for labile analytes that would otherwise degrade if stored in the traditional two-dimensional (2D) dried blood spot method. The protective mechanism for the dried blood spheroid microsampling platform was studied using scanning electron microscopy (SEM), which revealed the presence of a passivation thin film at the surface of the spheroid that serves to stabilize the interior of the spheroid against environmental stressors.

Analysis of non-conjugated steroids in water using paper spray mass spectrometry.

A novel strategy for the direct analysis of non-conjugated steroids in water using paper spray mass spectrometry (PS-MS) has been developed. PS-MS was used in the identification and quantification of non-conjugated (free) steroids in fish tank water samples. Data shown herein indicates that individual amounts of free steroids can be detected in aqua as low as; 0.

Determining Surface Energy of Porous Substrates by Spray Ionization.

We have developed a new spray-based method for characterizing surface energies of planar, porous substrates. Distinct spray modes (electrospray versus electrostatic spray), from the porous substrates, occur in the presence of an applied DC potential after wetting with solvents of different surface tension. The ion current resulting from the spray process is maximized when the surface energy of the porous substrate approaches the surface tension of the wetting solvent.