Two supramolecular hydrogelators containing a central disulfide moiety and terminal carboxylic acid groups are studied. On the one hand, the hydrogels are responsive to a reductive environment, which transforms the disulfide unit to the corresponding thiols. On the other hand, the hydrogels show pH response associated with the presence of carboxylic acid units. Gels are formed at pH below ≈4 while at higher pH values, ionization of the gelators provokes gel disassembly. The properties of the gel are exploited for the release, as a proof of concept, of Bromophenol Blue in the presence of the reducing species tris(2‐carboxyethyl)phosphine hydrochloride. Additionally, insulin is loaded into the hydrogels and protected from hydrolysis with simulated gastric fluid containing pepsin. Quantitative release of unaltered insulin, checked with an enzyme‐linked immunosorbent assay colorimetric assay, is observed upon treatment with pH 7.4 buffer. This behavior would permit the use of the new hydrogels for oral insulin delivery.

BackgroundLegionellosis is an uncommon form of pneumonia. After a clinical encounter, the necessary antibiotic treatment is available if the diagnosis is made early in the illness. Before the clinical encounter, early detection of the main pathogen involved, Legionella pneumophila, in hazardous environments is important in preventing infectious levels of this bacterium. In this study a qualitative test based on combined magnetic immunocapture and enzyme-immunoassay for the fast detection of Legionella pneumophila in water samples was compared with the standard method, in both comparative and collaborative trials. The test was based on the use of anti-Legionella pneumophila antibodies immobilized on magnetic microspheres. The final protocol included concentration by filtration, resuspension and immunomagnetic capture. The whole assay took less than 1 hour to complete.ResultsA comparative trial was performed against the standard culture method (ISO 11731) on both artificially and naturally contaminated water samples, for two matrices: chlorinated tap water and cooling tower water. Performance characteristics of the test used as screening with culture confirmation resulted in sensitivity, specificity, false positive, false negative, and efficiency of 96.6%, 100%, 0%, 3.4%, and 97.8%, respectively. The detection limit at the level under which the false negative rate increases to 50% (LOD50) was 93 colony forming units (CFU) in the volume examined for both tested matrices. The collaborative trial included twelve laboratories. Water samples spiked with certified reference materials were tested. In this study the coincidence level between the two methods was 95.8%.ConclusionResults demonstrate the applicability of this immunosensing technique to the rapid, simple, and efficient detection of Legionella pneumophila in water samples. This test is not based on microbial growth, so it could be used as a rapid screening technique for the detection of L. pneumophila in waters, maintaining the performance of conventional culture for isolation of the pathogen and related studies.

The use of nanocarriers for intracellular transport of actives has been extensively studied in recent years and represents a central area of Nanomedicine. The main novelty of this paper lies on the use of nanogels formed by a low molecular weight gelator (1). Here, nonpolymeric, molecular nanogels are successfully used for intracellular transport of two photodynamic therapy (PDT) agents, Rose Bengal (RB) and Hypericin (HYP).The two photosensitizers (PSs) exhibit different drawbacks for their use in clinical applications. HYP is poorly water-soluble, while the cellular uptake of RB is hindered due to its dianionic character at physiological pH values. Additionally, both PSs tend to aggregate precluding an effective PDT. Despite the different nature of these PSs, nanogels from gelator 1 provide, in both cases, an efficient intracellular transport into human colon adenocarcinoma cells (HT-29) and a notably improved PDT efficiency, as assessed by confocal laser scanning microscopy and flow cytometry. Furthermore, no significant dark toxicity of the nanogels is observed, supporting the biocompatibility of the delivery system. The developed nanogels are highly reproducible due to their non-polymeric nature and their synthesis is easily scaled up. The results here presented confirm thus the potential of molecular nanogels as valuable nanocarriers, capable of entrapping both hydrophobic and hydrophilic actives, for PDT of cancer.

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A pyrylium based fluorescent probe is able to detect mitochondrial nitric oxide and to discriminate phagocytic from non-phagocytic leukocytes.

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