Label-Free Homogeneous microRNA Detection in Cell Culture Medium Based on Graphene Oxide and Specific Fluorescence Quenching.

Label-free homogeneous optical detection of low concentration of oligonucleotides using graphene oxide in complex solutions containing proteins remains difficult. We used a colloidal graphene oxide (GO) as a fluorescent probe quencher to detect microRNA-21 spiked-in cell culture medium, overcoming previously reported problematic aspects of protein interference with graphene oxide. We used a "turn off" assay for specific quenching-based detection of oligo DNA-microRNA hybridization in solution. A fluorescein conjugated 30-mer single-stranded DNA (ssDNA) probe was combined with a complementary synthetic microRNA (18 nucleotides) target. The probe-target hybridization was detected by specific quenching due to photoinduced electron transfer (PET). On the next step, GO captures and quenches the unhybridized probe by fluorescence resonance energy transfer (FRET) in the presence of cell culture medium supplemented with platelet lysate, 0.1% sodium dodecyl sulfate (SDS), 0.1% Triton X-100 and 50% formamide. This resulted in sensitive measurement of the specific probe-target complexes remaining in solution. The detection is linear in the range of 1 nM and 8 nM in a single 100 µL total volume assay sample containing 25% cell culture medium supplemented with platelet lysate. We highlight a general approach that may be adopted for microRNA target detection within complex physiological media.

Biomimetic electrochemical sensor for the highly selective detection of azithromycin in biological samples.

A highly selective and sensitive molecularly imprinted polymer (MIP)-based electrochemical sensor was fabricated for the determination of azithromycin, a broad-spectrum macrolide antibiotic, from various biological samples (urine, tears, plasma). The reversible boronate ester bond-mediated, thin (~75 nm) MIP-based biomimetic recognition layer was electrodeposited in non-aqueous media onto the surface of a glassy carbon electrode (GCE). The surface morphology and the analytical performances of the developed sensor were assessed by scanning electron (SEM) and atomic force microscopy (AFM), electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). By employing an indirect electrochemical detection in the presence of 10 mM ferro/ferricyanide as redox probe, the sensor exhibited a very wide dynamic range (13.33 nM-66.67 µM), with an estimated detection limit in the subnanomolar range (0.85 nM azithromycin). The simple to construct sensor demonstrates reusability and good shelf-life, exhibiting remarkable selectivity over a wide number of structurally related and non-related antibiotics, commonly associated drugs and endogenous compounds.

Current evidence on thyroid related adverse events in patients treated with protein tyrosine kinase inhibitors.

Tyrosine kinase inhibitors (TKI) are gaining more ground in oncology, they are widely used in the treatment of multiple types of cancers; still important side effects limit their efficacy. The aim of this study is to evaluate the existing medical literature on TKI induced thyroid dysfunction, to assess the adverse effects of targeted therapy on thyroid function in oncological patients and to evaluate the effects of thyroid dysfunction on disease prognosis. We included in this review 22 original studies published between 2010 and 2019. We used the PubMed database to search for articles upon the development of hypothyroidism and hyperthyroidism in TKI treated patients. After a careful review of the existing literature, we selected the relevant studies and cross-referenced the bibliography of each paper. A number of 1641 patients were included in our review. We found that thyroid dysfunction is not a rare side effect of TKI treatment, approximately 33% of the total number of patients presented clinical hypothyroidism. We also studied the necessity of thyroid hormone substitution treatment, a quarter of evaluated patients needed substitution therapy. Multiple studies showed that there is a link between a patient developing hypothyroidism and progression free survival. Hypothyroidism is a frequent side effect of TKI treatment, which affects the quality of life, sometimes even determines physicians to stop TKI treatment altogether. Our study underlines the necessity of TSH baseline testing and monitoring in patients treated with TKI agents.