A new optical pH sensor based on polysulfone (PSU) and polyaniline (PANI) was developed. A transparent and flexible PSU membrane was employed as a support. The electrically conductive and pH-responsive PANI was deposited onto the membrane surface by in situ chemical oxidative polymerization (COP). The absorption spectra of the PANI-coated PSU membranes exhibited sensitivity to pH changes in the range of 4–12, which allowed for designing a dual wavelength pH optical sensor. The performance of the membranes was assessed by measuring their response starting from high pH and going down to low pH, and vice versa. It was found that it is necessary to precondition the sensor layers before each measurement due to the slight hysteresis observed during forward and backward pH titrations. PSU membranes with polyaniline coating thicknesses in the range of ≈100–200 nm exhibited fast response times of <4 s, which are attributed to the porous, rough and nanofibrillar morphology of the polyaniline coating. The fabricated pH sensor was characterized by a sigmoidal response (R² = 0.997) which allows for pH determination over a wide dynamic range. All membranes were stable for a period of more than six months when stored in 1 M HCl solution. The reproducibility of the fabricated optical pH sensors was found to be <0.02 absorption units after one month storage in 1 M HCl solution. The performance of the optical pH sensor was tested and the obtained pH values were compared with the results obtained using a pH meter device.

There is an increasing demand for sustainable and safe packaging technologies to improve consumer satisfaction, reduce food loss during storage and transportation, and track the quality status of food throughout its distribution. This study reports the fabrication of colorimetric pH-indicative and flame-retardant nanocomposite films (NCFs) based on polyvinyl alcohol (PVA) and nanoclays for smart and safe food packaging applications. Tough, flexible, and transparent NCFs were obtained using 15% nanoclay loading (PVA-15) with superior properties, including low solubility/swelling in water and high thermal stability with flame-retardant behavior. The NCFs showed average mechanical properties that are comparable to commercial films for packaging applications. The color parameters were recorded at different pH values and the prepared NCFs showed distinctive colorimetric pH-responsive behavior during the transition from acidic to alkaline medium with high values for the calculated color difference (∆E ≈ 50). The prepared NCFs provided an effective way to detect the spoilage of the shrimp samples via monitoring the color change of the NCFs during the storage period. The current study proposes the prepared NCFs as renewable candidates for smart food packaging featuring colorimetric pH-sensing for monitoring food freshness as well as a safer alternative choice for applications that demand films with fire-retardant properties.

Interleukin (IL)-19, a designated IL-20 subfamily cytokine, has been implicated in inflammatory disorders including rheumatoid arthritis, psoriasis and, lately, asthma. Here, through the analysis of transcriptomic datasets of lung tissue of large asthma cohorts, we report that IL-19 expression is upregulated in asthma and correlates with disease severity. The gene expression of IL-19 was significantly higher in lung tissue from patients with severe and mild/moderate asthma compared to healthy controls. IL-19 protein level, however, was significantly higher in the blood and saliva of patients with severe asthma compared to mild/moderate subgroups as measured by ELISA assay. IL-19 protein level was not affected by corticosteroid treatment in plasma. Our data provide insights into the potential use of IL-19 as a saliva marker for asthma severity and a potential therapeutic target.

Memory T cells play a central role in regulating inflammatory responses during asthma. However, tissue distribution of effector memory (T_EM) and central memory (T_CM) T-cell subtypes, their differentiation, and their contribution to the persistence of lung tissue inflammation during asthma are not well understood. Interestingly, an increase in survival and persistence of memory T cells was reported in asthmatic lungs, which may suggest a shift toward the more persistent T_CM phenotype. In this report, we investigated the differential distribution of memory T-cell subtypes during allergic lung inflammation and the mechanism regulating that. Using an OVA-sensitized asthma mouse model, we observed a significant increase in the frequency of T_CM cells in inflamed lungs compared to healthy controls. Interestingly, adoptive transfer techniques confirmed substantial infiltration of T_CM cells to lung tissues during allergic airway inflammation. Expression levels of T_CM homing receptors, CD34 and GlyCAM-1, were also significantly upregulated in the lung tissues of OVA-sensitized mice, which may facilitate the increased T_CM infiltration into inflamed lungs. Moreover, a substantial increase in the relative expression of T_CM profile-associated genes (EOMES, BCL-6, ID3, TCF-7, BCL-2, BIM, and BMI-1) was noted for T_EM cells during lung inflammation, suggesting a shift for T_EM into the T_CM state. To our knowledge, this is the first study to report an increased infiltration of T_CM cells into inflamed lung tissues and to suggest differentiation of T_EM to T_CM cells in these tissues. Therapeutic interference at T_CM infiltration or differentiations could constitute an alternative treatment approach for lung inflammation.

In this study, a biocompatible and non-toxic pH-responsive composite film was prepared for food packaging application. The films are composed from polyvinyl alcohol as the main polymeric matrix, nanoclay as a reinforcing component, and red cabbage extract as a non-toxic indicator. The prepared films showed lower water uptake values when the amount of nanoclay was increased up to 25%. It was observed that the films become brittle at high loading of nanoclay (40%). The prepared films exhibited color change in alkaline and acidic medium due to the presence of red cabbage extract, which turned pinkish in acidic medium and greenish in an alkaline environment. The prepared films were characterized by FTIR and visible spectroscopy. The maximum absorption in acidic medium was (λ_max = 527 nm), while a red-shift occurred in the alkaline medium (λ_max = 614 nm). Future work will focus on the crosslinking of the prepared films to improve their mechanical properties.