Development of a Portable Method for Serum Lithium Measurement Based on Low-Cost Miniaturized Ultrasonic Nebulization Coupled with Atmospheric-Pressure Air-Sustained Discharge

Dried Blood Spots and Miniaturized Ultrasonic Nebulization Microplasma Optical Emission Spectrometry for Point-of-Care Testing of Blood Lithium

Despite the significant importance of blood lithium (Li) detection in the treatment of bipolar disorder (BD), its point-of-care testing (POCT) remains a great challenge due to tedious sample preparation and the use of large-footprint atomic spectrometers. Herein, a system coupling dried blood spots (DBS) with a point discharge optical emission spectrometer equipped with a miniaturized ultrasonic nebulizer (MUN-μPD-OES) was developed for POCT of blood Li. Three microliters of whole blood were used to prepare a dried blood spot on a piece of filter paper to which 10 μL of eluent (1% (v/v) formic acid and 0.05% (v/v) Triton-X) was added. Subsequently, the paper was placed onto the vibrating steel membrane of the ultrasonic nebulizer and powered on to generate aerosol. The aerosol was directly introduced to the μPD-OES for quantification of Li by monitoring its atomic emission line at 670.8 nm. The proposed method minimized matrix interference caused by high levels of salts and protein. It is worth noting that the MUN suitably matches the needs of DBS sampling and can provide aerosolized introduction of Li into the assembled μPD-OES, thus eliminating all tedious sample preparation and the need for a commercial atomic spectrometer. Calibration response is linear in the therapeutic range and a limit of detection (LOD) of 1.3 μg L-1 is well below the Li minimum therapeutic concentration (2800 μg L-1). Li in mouse blood was successfully detected in real-time using MUN-μPD-OES after intraperitoneal injection of lithium carbonate, confirming that the system holds great potential for POCT of blood Li for patients with BD.

Existing and Emerging Technologies for Therapeutic Monitoring of Lithium: A Scoping Review

BACKGROUND/PURPOSE

Lithium is an effective psychoactive drug. It has a narrow therapeutic margin, with subtherapeutic levels or intoxication commonly occurring. Therapeutic drug monitoring (TDM) of lithium has several barriers. This scoping review aims to describe and analyze existing and emerging technologies for lithium TDM and to describe the lithium quantification parameters (precision, accuracy, detection limit) attributed to each technology.

METHOD

PubMed, Scopus, Web of Science, and Google Scholar were searched. Studies that described lithium quantification and complied with PRISMA-ScR guidelines were included. Articles selection was conducted by 2 researchers. Good precision was defined if its relative standard deviation <3%; acceptable, from 3% to 5%; and low, >5%. Accuracy was considered good if the error <5%; acceptable, 5%1 to 0%; and low if it was >10%.

RESULTS

Of the 2008 articles found, 22 met the inclusion criteria. Of these, 14 studies concerned laboratory devices, in which precision was found to be low in one third of cases, and half had good precision. Accuracy of one third was good, another third was low, and the remaining third did not report accuracy. The other 8 studies concerned portable devices, in which precision was low in more than 60% of the cases and good in 25% of the studies. Accuracy was low in 50% of the cases, and good in just over a third. Limits of detection included the therapeutic range of lithium in all studies.

CONCLUSIONS

Among emerging technologies for lithium TDM, precision and accuracy remain a challenge, particularly for portable devices.

Miniature mass spectrometers and their potential for clinical point-of-care analysis

Mass spectrometry (MS) has become a powerful technique for clinical applications with high sensitivity and specificity. Different from conventional MS diagnosis in laboratory, point-of-care (POC) analyses in clinics require mass spectrometers and analytical procedures to be friendly for novice users and applicable for on-site clinical diagnosis. The recent decades have seen the progress in the development of miniature mass spectrometers, providing a promising solution for clinical POC applications. In this review, we report recent advances of miniature mass spectrometers and their exploration in clinical applications, mainly including the rapid analysis of illegal drugs, on-site monitoring of therapeutic drugs, and detection of biomarkers. With improved analytical performance, miniature mass spectrometers are also expected to apply to more and more clinical applications. Some promising POC analyses that can be performed by miniature mass spectrometers in the future are discussed. Lastly, we also provide our perspectives on the challenges in technical development of miniature mass spectrometers for clinical POC analysis.

A microplasma optical emission spectrometry pen for point-of-care diagnosis of child blood lead

Blood lead levels (BLL) of children have attracted considerable attention due to their putative impact on intelligence decline. However, most methods used for the determination of blood lead typically require expensive, bulky, high power and gas consuming instrumentation, limiting their application for a point-of-care diagnosis. Herein we report the development and testing of a portable ballpoint discharge microplasma optical emission spectrometer (BD-OES pen) device having the potential to fill this needed measurement capability. The BD-OES pen utilizes a compact ballpoint-pen format integrating point-discharge microplasma, which permits the determination of child BLL requiring no more than 100 μL blood while providing high specificity, sensitivity and satisfactory limit of detection (0.73 μg L^-1). The handheld BD-OES pen is successfully used to diagnose BLL of 16 asymptomatic children on-site, two of whom had excessive the normal BLL. The pen may aid the on-site and rapid diagnosis of childhood BLL, particularly in low-income areas.

Lithium sensors based on photophysical changes of 1-aza-12-crown-4 naphthalene derivatives synthesized via Buchwald–Hartwig amination

Lithium sensor based on 1-aza-12-crown-4 naphthalene that can detect lithium ions through absorption and emission changes with the detection limit of 21 μM in an organic solvent.