The application of natural polymer matrices as medical device components or food packaging materials has gained a considerable popularity in recent years, this has occurred in response to the increasing plastic pollution hazard. Currently, constant progress is being made in designing two-component or three-component systems that combine natural materials which help to achieve a quality comparable to the purely synthetic counterparts. This study describes a green synthesis preparation of new bionanocomposites consisting of starch/chitosan/graphene oxide (GO), that possess improved biological activities; namely, good tolerability by human cells with concomitant antimicrobial activity. The structural and morphological properties of bionanocomposites were analyzed using the following techniques: dynamic light scattering, scanning and transmission electron microscopy, wettability and free surface energy determination, and Fourier transform infrared spectroscopy. The study confirmed the homogenous distribution of GO layers within the starch/chitosan matrix and their large particle size. The interactions among the components were stronger in thin films. Additionally, differential scanning calorimetry analysis, UV–vis spectroscopy, surface colour measurements, transparency, water content, solubility, and swelling degree of composites were also performed. The mechanical parameters, such as tensile strength and elongation at break (EAB) were measured in order to characterise the functional properties of obtained nanocomposites. The GO additive altered the thermal features of the composites and decreased their brightness. The EAB of composite was improved by the introduction of GO. Importantly, cell-based analyses revealed no toxic effect of the composites on HaCat keratinocytes and HepG2 hepatoma cells, although a pronounced bacteriostatic effect against various strains of pathogenic bacteria was observed. In conclusion, the starch/chitosan/GO nanocomposites reveal numerous useful physicochemical and biological features, which make them a promising alternative for purely synthetic materials.

Polymer nanocomposites containing nanometals became a subject of interest due to their bactericidal properties. Different polysaccharides have been used as matrices for nanosilver and nanogold synthesis. In this study, we present a novel, environmentally friendly method for the preparation of sodium alginate/nanosilver/graphene oxide (GOX) and sodium alginate/nanogold/graphene oxide GOX nanocomposites and their characteristics. The formation of approximately 10–20 nm ball-shaped Ag and Au nanoparticles was confirmed by UV–vis spectroscopy, scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectra. The incorporation of GOX sheets within the ALG matrix improved the thermal stability of the nanocomposites film, which was measured using the differential scanning calorimetry (DSC). We also estimated the molecular weights of polysaccharide chains of the matrix with the size exclusion chromatography coupled with multiangle laser light scattering and refractometric detectors (HPSEC-MALLS-RI). The composites were more prone to enzymatic hydrolysis. The strongest bacteriostatic activity was observed for the sample containing nanosilver.

Keeping horses in good condition requires providing them with living conditions that meet welfare requirements. These animals should be accommodated with suitable space, access to high nutritional fodder and water, and a suitable microclimate in their shelters. When it comes to the environment in the stables, a serious problem is created by particulate matter (PM), which consists of bacteria. PM concentration may be responsible for developing multiple lower respiratory tract diseases in horses, including allergies and recurrent airway obstruction (RAO). In turn, these ailments may lead to decreasing equine physical and mental fitness. Additionally, people who spend time in the stables are exposed to the same harmful factors. The study was conducted in Udórz Stud Farm located in the southern region of Poland. The study was carried out in 2 different types of stables: 3 runners (a type of stable where horses are housed together and occasionally linked up, e.g., for feeding or grooming) and 2 box stables. The research continued for 2 years and the samples were collected in each season. The bioaerosol samples were collected using a six-stage Andersen-Graseby cascade impactor to assess size distribution and concentrations of airborne bacteria. PM concentration was analyzed using the DustTrak™ II Aerosol Monitor 8530, while microclimate parameters were measured using the Kestrel 5000 Weather Meter. There are almost no studies concerning size distribution of airborne bacteria, individual PM fractions, and the impact of everyday handling on the changes in the bioaerosol and PM concentration. This preliminary study provided basic information on this subject. We have revealed a strong correlation between high PM and bacterial aerosol concentrations. Higher contamination levels were recorded in runners, as compared to box stables. The highest bacterial aerosol level was detected in the spring. The analysis of the fractions of the bacterial aerosol in the stables indicated the highest share of ultra-fine fraction (0.65–2.1 µm), while respirable fraction (below 4.7 µm) exceeded 75%. It was established that the concentration of the bacterial aerosol inside the stables was many times higher than outside. It depended significantly on everyday activities undertaken in the stables, like feeding or cleaning. Taking the above into account, a different cleaning system should be developed (a wet cleaning system, with the use of water) and excrement should be removed more frequently.

Zoos are very popular facilities visited by entire families with children, who come there to watch live animals. Zoos also provide workplaces for a large number of people directly looking after the animals. For places designed to house animals, regardless of whether they are farm animals, pets, or zoo animals, a higher concentration of both dust and potentially harmful bioaerosols can be expected. Unfortunately, there are almost no studies concerning the concentration of bacterial bioaerosols and particulate matter in animal shelters that would answer the question whether the level of these pollutants is constant or variable and dependent on a particular zoo, group of animals, their number in enclosures, or season. This study aimed to assess the levels of bacterial aerosol in rooms intended for animals (giraffes, camels, elephants, kangaroos, and colobinae) in the Silesian Zoological Garden in Chorzów (Poland). The bioaerosol samples were collected using a six-stage Andersen cascade impactor to assess the concentrations and size distribution of airborne bacteria. Particulate matter (PM10) was assessed using an electronic dust meter. Measurements of microclimate parameters were carried out using the Airflow™ Instruments Velocity Meter TA440, while gas concentrations were determined applying GFG Microtector II G450. The results showed that the concentration of airborne bacteria varied significantly between facilities for the analyzed animal groups. The lowest concentration of the total bacterial aerosol was observed in enclosures for colobinae (approx. 850 CFU/m³), while the highest—in rooms for elephants (approx. 105,600 CFU/m³). The average share of respirable fraction of bacteria was quite high, with values ranging from 62.9 (colobinae) to 86.9% (elephants), indicating potential harmfulness to the health of exposed people. PM10 concentrations were relatively low (10–86 μg/m³) and did not exceed the limit values for occupational exposure. Moreover, the levels of bacterial bioaerosol in almost all cases did not exceed the limit values. As the animals constitute a significant source of bioaerosol, attention should be paid to thorough cleaning of animals and their shelters, as well as maintaining appropriate levels of microclimate parameters in the facilities.