Alginates are the most widely used natural polymers in the pharmaceutical, food and cosmetic industries. Usually, they are applied as a thickening, gel-forming and stabilizing agent. Moreover, the alginate-based formulations such as matrices, membranes, nanospheres or microcapsules are often used as delivery systems. Alginate microparticles (AMP) are biocompatible, biodegradable and nontoxic carriers, applied to encapsulate hydrophilic active substances, including probiotics. Here, we report the methods most frequently used for AMP production and encapsulation of different actives. The technological parameters important in the process of AMP preparation, such as alginate concentration, the type and concentration of other reagents (cross-linking agents, oils, emulsifiers and pH regulators), agitation speed or cross-linking time, are reviewed. Furthermore, the advantages and disadvantages of alginate microparticles as delivery systems are discussed, and an overview of the active ingredients enclosed in the alginate carriers are presented.

To realize the health benefits of probiotic bacteria, they must withstand processing and storage conditions and remain viable after use. The encapsulation of these probiotics in the form of microspheres containing tapioca flour as a prebiotic and vehicle component in their structure or shell affords symbiotic effects that improve the survival of probiotics under unfavorable conditions. Microencapsulation is one such method that has proven to be effective in protecting probiotics from adverse conditions while maintaining their viability and functionality. The aim of the work was to obtain high-quality microspheres that can act as carriers of Lactobacillus casei bacteria and to assess the impact of encapsulation on the viability of probiotic microorganisms in alginate microspheres enriched with a prebiotic (tapioca flour) and additionally coated with hyaluronic acid, chitosan, or gelatin. The influence of the composition of microparticles on the physicochemical properties and the viability of probiotic bacteria during storage was examined. The optimal composition of microspheres was selected using the design of experiments using statistical methods. Subsequently, the size, morphology, and cross-section of the obtained microspheres, as well as the effectiveness of the microsphere coating with biopolymers, were analyzed. The chemical structure of the microspheres was identified by using Fourier-transform infrared spectrophotometry. Raman spectroscopy was used to confirm the success of coating the microspheres with the selected biopolymers. The obtained results showed that the addition of tapioca flour had a positive effect on the surface modification of the microspheres, causing the porous structure of the alginate microparticles to become smaller and more sealed. Moreover, the addition of prebiotic and biopolymer coatings of the microspheres, particularly using hyaluronic acid and chitosan, significantly improved the survival and viability of the probiotic strain during long-term storage. The highest survival rate of the probiotic strain was recorded for alginate-tapioca flour microspheres coated with hyaluronic acid, at 5.48 log CFU g^-1. The survival rate of L. casei in that vehicle system was 89% after storage for 30 days of storage.

Bio-based nanoemulsions are part of green pest management for sustainable agriculture. This study assessed the physicochemical properties and the herbicidal activities of the peppermint essential oil nanoemulsions (PNs) in concentrations 1.0–10% stabilized by Eco-Polysorbate 80 on germinating seeds and young plants of maize and barnyard grass. Based on the design of experiment (DOE) results, the final nanoemulsion formulations were obtained with 1, 1.5, 2, and 5% of essential oil concentration. Biological analyses were conducted to select the most promising sample for selective control of barnyard grass in maize. Seedlings growing in the presence of PNs displayed an overall inhibition of metabolism, as expressed by the calorimetric analyses, which could result from significant differences in both content and composition of carbohydrates. Concentration–response sub estimation showed that leaf-sprayed concentration of PN causing 10% of maize damage is equal to 2.2%, whereas doses causing 50% and 90% of barnyard grass damage are 1.1% and 1.7%, respectively. Plants sprayed with PN at 5% or 10% concentration caused significant drops in relative water content in leaves and Chlorophyll a fluorescence 72 h after spraying. In summary, peppermint nanoemulsion with Eco-Polysorbate 80 at 2% concentration is a perspective preparation for selective control of barnyard grass in maize. It should be analyzed further in controlled and field conditions.

Probiotic bacteria confer health benefits to their host, support the intestinal microbiome and fight antibiotic resistance. Probiotic products are used in the food and pharmaceutical industries and, in recent years, have become increasingly popular in the cosmetic industry. However, in the case of cosmetics, it is difficult to meet microbiological requirements while maintaining viable cells. The aim of this research study was to develop an effective way of introducing live bacteria (a strain of L. casei) into cosmetic formulations. A method of encapsulation of the bacteria was used to increase their viability. As part of the results, the effective carriers for the strain of L. casei are reported. Alginate microspheres were prepared for the systems to protect the microorganisms against external factors, such as temperature, UV light and preservatives. The obtained probiotic-loaded alginate microspheres were then used as the active ingredient of cosmetic formulations. Additionally, a preservative system was carefully selected to ensure the microorganisms’ viability and the microbiological stability of the products. The obtained results showed a significant improvement in the survival of the microencapsulated probiotic strain in the cosmetic formulations containing antimicrobial agents (6.13 log CFU/g after 120 days of storage) compared with the formulation containing the non-immobilised probiotic strain, where complete elimination of bacterial cells was observed.

Skin dysbiosis—a perturbed microbiome balance—is associated with numerous skin conditions. To manage dysbiosis, pre- and probiotics may be used as modulators to restore microbial balance. In this study, Lactobacillus casei ATCC 393-based novel probiotic formulation has been elaborated. The antimicrobial activity of L. casei against Staphylococcus epidermidis and Staphylococcus aureus was studied using kill test and well diffusion assay. The probiotic strain was found to be active against S. aureus (0.81 and 0.99 log reduction of S. aureus cells after 5 and 24 h, respectively). The well diffusion assay showed that L. casei metabolites were active against S. aureus (zone of inhibition: 5 mm). Alginate-prebiotic (tapioca flour)-encapsulated probiotic strain microspheres were used as active ingredients in a topical formulation. The safety and efficacy of this formulation was determined in vitro in human keratinocytes (HaCaT) and fibroblasts (HSF), analyzing cytotoxicity, cell proliferation rate, and proinflammatory cytokine (IL-6 and IL-8) release. In addition, the formulation+n exhibited regenerative potential in the scratch test. In vitro studies showed that the formulation containing MP reduced the survival of pathogenic strains (E. coli, S. aureus, C. albicans, C. neoformans) compared to the base formulation, devoid of lactic acid bacteria (even by 2.82 log).

Oleogels (organogels) are systems resembling a solid substance based on the gelation of organic solvents (oil or non-polar liquid) through components of low molecular weight or oil-soluble polymers. Such compounds are organogelators that produce a thermoreversible three-dimensional gel network that captures liquid organic solvents. Oleogels based on natural oils are attracting more attention due to their numerous advantages, such as their unsaturated fatty acid contents, ease of preparation, and safety of use. As a result of the research, two oleogels were developed, into which freeze-dried alginate carriers with a probiotic, L. casei, were incorporated. Two techniques were used to produce probiotic-loaded capsules—extrusion and emulsification. Alginate beads obtained by the extrusion process have a size of approximately 1.2 mm, while much smaller microspheres were obtained using the emulsification technique, ranging in size from 8 to 17 µm. The trehalose was added as a cryoprotectant to improve the survival rate of probiotics in freeze-dried alginate carriers. The encapsulation efficiency for both of the methods applied, the emulsification and the extrusion technique, was high, with levels of 90% and 87%, respectively. The obtained results showed that the production method of probiotic-loaded microspheres influence the bacterial viability. The better strain survival in the developed systems was achieved in the case of microspheres produced by the emulsification (reduction in bacterial cell viability in the range of 1.98–3.97 log in silica oleogel and 2.15–3.81 log in sucragel oleogel after 7 and 30 days of storage) than by the extrusion technique (after a week and a month of oleogel storage, the decrease in cell viability was 2.52–4.52 log in silica oleogel and 2.48–4.44 log in sucragel oleogel).