Monitoring gestational diabetes at the point-of-care via dual glycated albumin lateral flow assays in conjunction with a handheld reader.

Chronic conditions like diabetes require monitoring of vital biomarkers over extended periods of time. Monitoring gestational diabetes mellitus (GDM) is crucial to avoid short- and long-term adverse effects on both mother and infant. Providing monitoring systems to patients at the point-of-care (POC) has the potential to help mitigate these effects. In this manuscript, we propose the use of a sensing system combining lateral flow assays (LFAs) with a handheld colorimetric reader for use in tracking the glycemic status of a GDM patient at the POC. Current strategies of GDM monitoring include glucose and HbA1c measurements. These are often too frequent or not frequent enough for effective monitoring. Hence, we have developed a sensor for an intermediate interval biomarker - glycated albumin (GA). Based on the half-life of the protein, GA is measured once every 2-3 weeks. Here we first present two lateral flow assays, one for GA and another for total serum albumin used in conjunction with a handheld reader to read the colorimetric signals. Both assays have a sandwich aptamer format and measure the target proteins in their physiologically relevant ranges. The GA assay has a dynamic range of 3-20 mg ml-1 and the serum albumin assay has a range of 20-50 mg ml-1 without any sample dilution. Both LFAs were then incorporated into a single dual assay cartridge such that both assays could run simultaneously and provide the % glycated albumin value from a single test. Thus, the dual assay cartridge plus reader system has the potential to provide an effective platform for measuring GA for tracking GDM at the POC.

Comparison of the Influence of a Packaged Fruit Juice on the Bacterial Adhesion on a Glass Ionomer Cement and an Esthetic Restorative Material In Vitro.

Objective: The aim of this research was to evaluate and compare the effect of a packaged orange juice on the two most commonly used restorative materials in pediatric dentistry. Methodology: Fifteen samples each of 6 mm diameter and 2 mm thickness of a glass ionomer cement (GIC) and an esthetic restorative material were prepared using silicone rings. These were exposed to a packaged orange fruit juice and then placed in a standard culture of Streptococcus mutans. The bacterial adhesion to these samples was evaluated after exposure to the fruit juice for 1 day and for 7 days. Results: Results from the study show that there is a decrease in the colony forming unit (CFU) after exposure to the packaged fruit juice as opposed to the studies using carbonated acidic drinks, which have shown a consistent rise in the CFU due to a change in the surface morphology. Conclusion: Within the limitations of this study, it was seen that the consumption of fruit juice may not cause a deteriorating effect on the restorative materials considered. However, the results were not statistically significant and further research is necessary to come to a conclusion regarding the reduction in the bacterial count after exposure to the fruit juice. Clinical implications: With further research, such studies can help in improving the diet counseling practices. How to cite this article: Patel A, Belsare SP, Jajoo SS, et al. Comparison of the Influence of a Packaged Fruit Juice on the Bacterial Adhesion on a Glass Ionomer Cement and an Esthetic Restorative Material In Vitro. Int J Clin Pediatr Dent 2022;15(3):327-331.

Development of a colorimetric paper fluidic dipstick assay for measurement of glycated albumin to monitor gestational diabetes at the point-of-care.

Gestational diabetes mellitus (GDM) affects between 2 and 14% of pregnant women in the United States every year. Currently, glucose and hemoglobin A1c (HbA1c) are the standard biomarkers used to monitor GDM but HbA1c is representative of 2-3 months of glycemic data and is too infrequent for managing clinical impact of GDM while glucose provides multiple daily readings which arguably are not entirely necessary for mild to moderate GDM and often result in non-compliance from the patient's side. Thus, there is a need for an intermediate biomarker which can be used effectively to monitor the glycemic status of GDM patients. Serum albumin, the most abundant protein in blood, undergoes non-enzymatic glycation in the bloodstream. Owing to its half-life of ~21 days, it can effectively be used as an intermediate biomarker. Normal level of glycation of albumin is between 10 and 16% whereas in diabetic patients it is much higher, between 16 and 40%. Thus, a point-of-care (POC) monitoring system to detect glycated albumin (GA) as a % of total serum albumin has been developed here. Specifically, a dipstick paper fluidic test to measure % glycated albumin has been developed that used an aptamer assay with gold nanoparticles to produce colorimetric measurements. Both the glycated and unglycated versions of albumin were measured in their relevant physiological concentration ranges - 50 µM-300 µM with a limit of detection (LoD) of 6.5 µM for glycated albumin and 500 µM-750 µM with a LoD of 21 µM for unglycated serum albumin. The use of aptamers as recognition elements, instead of commonly used antibodies, not only provided the required sensitivity, specificity, and dynamic range but they also have the added advantage of being stable at room temperature for an extended period of time providing the potential for these dipstick tests to be used for GDM monitoring at the point-of-care (POC).

Aptamer-switching optical bioassay for citrulline detection at the point-of-care.

Researchers have found that decreased levels of circulating citrulline could be an indicator of intestinal failure. Typically, this amino acid, which is produced by the intestinal mucosa cells, circulates in the blood at a physiological level of ∼40 µM. The current methodology for measuring this level involves the use of bulky equipment, such as mass spectroscopy and analysis at a central laboratory, which can delay diagnosis. Therefore, the current detection method is unsuited for routine monitoring at a doctor's office. Our research group proposes the development of a point-of-care (POC) device to overcome this issue. The proposed device utilizes surface-enhanced Raman spectroscopy (SERS) coupled with a specifically designed aptamer, capable of binding to citrulline, conjugated to colloidal gold nanoparticles. The assay is then embedded within a vertical flow paper-fluidic platform as a deliverable at the POC, and a handheld Raman spectrometer (638-nm excitation) was used to interrogate the sample. Results showed good dynamic range and specificity with an average 73% decrease in SERS signal intensity with increasing concentrations of citrulline (0 to 50 µM) in phosphate-buffered saline compared to its controls: glycine, glutamine, histidine, and valine, which showed less than 10% average decrease in the presence of 200 µM of each analyte. Further, the limit of detection (LOD) within a chip was determined to be 0.56 µM, whereas the LOD across chips was below 10 µM.

Stability and Mobility of Magnetic Nanoparticles in Biological Environments Determined from Dynamic Magnetic Susceptibility Measurements.

Low tumor accumulation following systemic delivery remains a key challenge for advancing many cancer nanomedicines. One obstacle in engineering nanoparticles for high tumor accumulation is a lack of techniques to monitor their stability and mobility in situ. One way to monitor the stability and mobility of magnetic nanoparticles biological fluids in situ is through dynamic magnetic susceptibility measurements (DMS), which under certain conditions provide a measure of the particle's rotational diffusivity. For magnetic nanoparticles modified to have commonly used biomedical surface coatings, we describe a systematic comparison of DMS measurements in whole blood and tumor tissue explants. DMS measurements clearly demonstrated that stability and mobility changed over time and from one medium to another for each different coating. It was found that nanoparticles coated with covalently grafted, dense layers of PEG were the only ones to show good stability and mobility in all settings tested. These studies illustrate the utility of DMS measurements to estimate the stability and mobility of nanoparticles in situ, and which can provide insights that lead to engineering better nanoparticles for in vivo use.

Stroma-derived extracellular vesicles deliver tumor-suppressive miRNAs to pancreatic cancer cells.

The biology of tumor-associated stroma (TAS) in pancreatic ductal adenocarcinoma (PDAC) is not well understood. The paradoxical observation that stroma-depletion strategies lead to progression of PDAC reinforced the need to critically evaluate the functional contribution of TAS in the initiation and progression of PDAC. PDAC and TAS cells are unique in their expression of specific miRNAs, and this specific miRNA expression pattern alters host to tumor microenvironment interactions. Using primary human pancreatic TAS cells and primary xenograft PDAC cells co-culture, we provide evidence of miRNA trafficking and exchanging between TAS and PDAC cells, in a two-way, cell-contact independent fashion, via extracellular vesicles (EVs) transportation. Selective packaging of miRNAs into EVs led to enrichment of stromal specific miR-145 in EVs secreted by TAS cells. Exosomes, but not microvesicles, derived from human TAS cells demonstrated a tumor suppressive role by inducing PDAC cell apoptosis. This effect was mitigated by anti-miR-145 sequences. Our data suggest that TAS-derived miRNAs are delivered to adjacent PDAC cells via exosomes and suppress tumor cell growth. These data highlight that TAS cells secrete exosomes carrying tumor suppressive genetic materials, a possible anti-tumor capacity. Future work of the development of patient-derived exosomes could have therapeutic implications for unresectable PDAC.

Salmonella enterica Serovar Typhimurium Alters the Extracellular Proteome of Macrophages and Leads to the Production of Proinflammatory Exosomes.

Salmonella enterica serovar Typhimurium is a Gram-negative bacterium, which can invade and survive within macrophages. Pathogenic salmonellae induce the secretion of specific cytokines from these phagocytic cells and interfere with the host secretory pathways. In this study, we describe the extracellular proteome of human macrophages infected with S Typhimurium, followed by analysis of canonical pathways of proteins isolated from the extracellular milieu. We demonstrate that some of the proteins secreted by macrophages upon S Typhimurium infection are released via exosomes. Moreover, we show that infected macrophages produce CD63+ and CD9+ subpopulations of exosomes at 2 h postinfection. Exosomes derived from infected macrophages trigger the Toll-like receptor 4-dependent release of tumor necrosis factor alpha (TNF-α) from naive macrophages and dendritic cells, but they also stimulate secretion of such cytokines as RANTES, IL-1ra, MIP-2, CXCL1, MCP-1, sICAM-1, GM-CSF, and G-CSF. Proinflammatory effects of exosomes are partially attributed to lipopolysaccharide, which is encapsulated within exosomes. In summary, we show for the first time that proinflammatory exosomes are formed in the early phase of macrophage infection with S Typhimurium and that they can be used to transfer cargo to naive cells, thereby leading to their stimulation.