Ni(II)NTA AuNPs as a low-resource malarial diagnostic platform for the rapid colorimetric detection of Plasmodium falciparum Histidine-Rich Protein-2

A novel fluorescent probe based on a tripeptide-Cu(II) complex system for detection of histidine and its application on test strips and smartphone

Herein, we reported a novel peptide-based fluorescent probe DSSH for highly selective and sensitive detections of both Cu²⁺ and _l-histidine (_l-His). DSSH exhibited different color changes and fluorescence "on-off" response toward Cu²⁺ with a 2:1 binding stoichiometry, and the limit of detection (LOD) for Cu²⁺ was calculated to be 22.9 nM. The in situ formed DSSH-Cu²⁺ ensemble showed obvious fluorescence "off-on" response to _l-His based on replacement reaction with Cu²⁺, as well as the discernable color changes under 365 nm UV lamp irradiation with "naked eye". The specificity of Cu²⁺/_l-His interactions allowed _l-His to be determined without interference from other amino acids, and the detection limit of DSSH-Cu²⁺ ensemble response to _l-His was determined as 25.7 nM. Notably, DSSH was successfully applied for detecting Cu²⁺ and _l-His in RKO living cells owing to its remarkable fluorescence behavior and low cytotoxicity. Test strips experiments suggested that DSSH can recognize Cu²⁺ and _l-His together by a remarkable fluorescence change. More importantly, smartphone was combined with _l-His solutions of different concentrations and converted into digital values through RGB channels, which was successfully used for semi-quantitative identification of _l-His, and the limit of detection (LOD) was 0.97 μM.

Gold Nanoparticles for Diagnostics: Advances towards Points of Care

The remarkable physicochemical properties of gold nanoparticles (AuNPs) have prompted developments in the exploration of biomolecular interactions with AuNP-containing systems, in particular for biomedical applications in diagnostics. These systems show great promise in improving sensitivity, ease of operation and portability. Despite this endeavor, most platforms have yet to reach maturity and make their way into clinics or points of care (POC). Here, we present an overview of emerging and available molecular diagnostics using AuNPs for biomedical sensing that are currently being translated to the clinical setting.

Mobile phone imaging and cloud-based analysis for standardized malaria detection and reporting

Rapid diagnostic tests (RDTs) have been widely deployed in low-resource settings. These tests are typically read by visual inspection, and accurate record keeping and data aggregation remains a substantial challenge. A successful malaria elimination campaign will require new strategies that maximize the sensitivity of RDTs, reduce user error, and integrate results reporting tools. In this report, an unmodified mobile phone was used to photograph RDTs, which were subsequently uploaded into a globally accessible database, REDCap, and then analyzed three ways: with an automated image processing program, visual inspection, and a commercial lateral flow reader. The mobile phone image processing detected 20.6 malaria parasites/microliter of blood, compared to the commercial lateral flow reader which detected 64.4 parasites/microliter. Experienced observers visually identified positive malaria cases at 12.5 parasites/microliter, but encountered reporting errors and false negatives. Visual interpretation by inexperienced users resulted in only an 80.2% true negative rate, with substantial disagreement in the lower parasitemia range. We have demonstrated that combining a globally accessible database, such as REDCap, with mobile phone based imaging of RDTs provides objective, secure, automated, data collection and result reporting. This simple combination of existing technologies would appear to be an attractive tool for malaria elimination campaigns.

Two low-cost digital camera-based platforms for quantitative creatinine analysis in urine

In clinical analysis creatinine is a routine biomarker for the assessment of renal and muscular dysfunctions. Although several techniques have been proposed for a fast and accurate quantification of creatinine in human serum or urine, most of them require expensive or complex apparatus, advanced sample preparation or skilled operators. To circumvent these issues, we propose two home-made platforms based on a CD Spectroscope (CDS) and Computer Screen Photo-assisted Technique (CSPT) for the rapid assessment of creatinine level in human urine. Both systems display a linear range (r(2) = 0.9967 and 0.9972, respectively) from 160 μmol L(-1) to 1.6 mmol L(-1) for standard creatinine solutions (n = 15) with respective detection limits of 89 μmol L(-1) and 111 μmol L(-1). Good repeatability was observed for intra-day (1.7-2.9%) and inter-day (3.6-6.5%) measurements evaluated on three consecutive days. The performance of CDS and CSPT was also validated in real human urine samples (n = 26) using capillary electrophoresis data as reference. Corresponding Partial Least-Squares (PLS) regression models provided for mean relative errors below 10% in creatinine quantification.