A strategy for low-cost portable monitoring of plasma drug concentrations using a sustainable boron-doped-diamond chip.

On-site monitoring of plasma drug concentrations is required for effective therapies. Recently developed handy biosensors are not yet popular owing to insufficient evaluation of accuracy on clinical samples and the necessity of complicated costly fabrication processes. Here, we approached these bottlenecks via a strategy involving engineeringly unmodified boron-doped diamond (BDD), a sustainable electrochemical material. A sensing system based on a ∼1 cm2 BDD chip, when analysing rat plasma spiked with a molecular-targeting anticancer drug, pazopanib, detected clinically relevant concentrations. The response was stable in 60 sequential measurements on the same chip. In a clinical study, data obtained with a BDD chip were consistent with liquid chromatography-mass spectrometry results. Finally, the portable system with a palm-sized sensor containing the chip analysed ∼40 µL of whole blood from dosed rats within ∼10 min. This approach with the 'reusable' sensor may improve point-of-monitoring systems and personalised medicine while reducing medical costs.

Profiling of microbiota in liquid baby formula consumed with an artificial nipple.

It is suspected that oral bacteria are transferred to the liquid baby formula through the artificial nipple and multiply in the bottle after feeding. In the present study, in order to understand the influence of bacteria on liquid baby formula after feeding, the transfer of oral bacteria through artificial nipples and their survival in liquid baby formula were examined immediately after drinking as well as after storage at 4°C for 3 h. Four healthy human subjects (20-23 years old) were asked to drink liquid baby formula (Aptamil®, ca. 50 mL) from baby bottles using artificial nipples. Samples of the liquid baby formula (immediately after drinking and 3 h later) were inoculated onto blood agar plates and incubated anaerobically at 37°C for 7 days. Salivary samples from each subject and 6 newborn infants were also cultured. Genomic DNA was extracted from individual colonies, and bacterial species were identified by 16S rRNA gene sequencing. The mean amounts of bacteria (CFU/mL) were (3.2 ± 3.0) ×104 and (3.4 ± 3.3) ×104 immediately after drinking and 3 h later, respectively. Streptococcus (41.6 and 40.5%), Actinomyces (24.3 and 21.5%) and Veillonella (16.2 and 11.0%) were recovered from the samples immediately after drinking and 3 h later, respectively. On the other hand, Streptococcus (38.9%), Actinomyces (17.1%), Neisseria (9.1%), Prevotella (6.9%), Rothia (6.9%) and Gemella (5.1%) were predominant in the saliva of adult subjects, and Streptococcus (65.2%), Staphylococcus (18.5%), Gemella (8.2%) and Rothia (5.4%) were predominant in the saliva of infant subjects. From these findings, oral bacteria, e.g., Streptococcus, Gemella and Rothia, were found to transfer into the liquid baby formula through artificial nipples, and the bacterial composition in the remaining liquid baby formula was found to resemble that of human saliva. The bacterial levels were similar between immediately after drinking and when stored at 4°C for 3 h, suggesting that the remaining liquid baby formula may be preserved in a refrigerator for a specified amount of time.