Sustainable, Alginate-Based Sensor for Detection of Escherichia coli in Human Breast Milk.

There are no existing affordable diagnostics for sensitive, rapid, and on-site detection of pathogens in milk. To this end, an on-site colorimetric-based sustainable assay has been developed and optimized using an L16 (54) Taguchi design to obtain results in hours without PCR amplification. To determine the level of Escherichia coli (E. coli) contamination, after induction with 150 µL of breast milk, the B-Per bacterial protein extraction kit was added to a solution containing an alginate-based microcapsule assay. Within this 3 mm spherical novel sensor design, X-Gal (5-Bromo-4-Chloro-3-Indolyl ß-d-Galactopyranoside) was entrapped at a concentration of 2 mg/mL. The outward diffusing X-Gal was cleaved by ß-galactosidase from E. coli and dimerized in the solution to yield a blue color after incubation at 40 °C. Color intensity was correlated with the level of E. coli contamination using a categorical scale. After an 8 h incubation period, a continuous imaging scale based on intensity normalization was used to determine a binary lower limit of detection (LOD), which corresponded to 102 colony forming unit per mL (CFU/mL) and above. The cost of the overall assay was estimated to be $0.81 per sample, well under the $3 benchmark for state-of-the-art immune-based test kits for pathogen detection in biofluids. Considering the reported binary LOD cutoff of 102 CFU/mL and above, this proposed hydrogel-based assay is suited to meet global requirements for screening breast milk or milk for pathogenic organisms of 104 CFU/mL, with a percentage of false positives to be determined in future efforts.

Benchmarking Site Activation and Patient Enrollment.

Clinical trial conduct poses numerous challenges, many pertaining to patient recruitment. The primary objectives of this study were to update benchmarks on site activation and patient enrollment gathered in previous Tufts CSDD studies and examine current usage of recruitment and retention tactics. The data collection focused on site activation and patient enrollment metrics used for studies. Analyses were conducted comparing results from 2012, 2019 and 2023. The results indicate that actual enrollments exceeded planned enrollments for a majority of studies and timelines were shorter than expected. In addition, differences were found for enrollment achievement by global region and site type. Further investigation into studies conducted during a later time frame and post-pandemic could be compared with current benchmarks to examine differences.