Zein nanoparticles for drug delivery: Preparation methods and biological applications.

Zein, a vegetable protein extracted from corn (Zea mays L.), forms a gastro-resistant and mucoadhesive polymer that is cheap and easy to obtain and facilitates the encapsulation of bioactives with hydrophilic, hydrophobic, and amphiphilic properties. The methods used for synthesizing these nanoparticles include antisolvent precipitation/nanoprecipitation, pH-driven, electrospraying, and solvent emulsification-evaporation methods. Each method has its advantages in the preparation of nanocarriers, nevertheless, all of them enable the production of zein nanoparticles that are stable and resistant to environmental factors, with different biological activities required in the cosmetic, food, and pharmaceutical industries. Therefore, zein nanoparticles are promising nanocarriers that can encapsulate various bioactives with anti-inflammatory, antioxidant, antimicrobial, anticancer, and antidiabetic properties. This article reviews the principal methods for obtaining zein nanoparticles containing bioactives, the advantages and characteristics of each method, as well as the main biological applications of nanotechnology-based formulations.

Tissue response and retention of micro- and nanosized liposomes in infarcted mice myocardium after ultrasound-guided transthoracic injection.

Different carrier systems have been investigated for myocardial delivery of biopharmaceuticals for heart disease. Here, we aimed to evaluate the heart retention and tissue response of liposomes intended for cardiac drug delivery. Liposomes were produced by the lipid thin film hydration method followed by sonication. Cytocompatibility tests were performed in murine L929 fibroblasts and H2c9 cardiomyocytes using the Alamar Blue assay. In vivo experiments were assessed in a model of myocardial infarction induced by isoproterenol in mice. Cardiac delivery of fluorescent liposomes (rhodamine B-labeled) with different mean sizes (165 nm, 468 nm, 1551 nm and 1954 nm) was performed by ultrasound-guided transthoracic injection. After three days, mice were euthanized for histological evaluation using optical and fluorescence microscopy. No cytotoxic lipid concentrations were determined in the range 9.3 - 120 µM for fibroblasts and cardiomyocytes exposed to liposomes. In vivo, large liposomes induced significant inflammation in myocardium compared with the control group (p < 0.0001). In contrast, heart mice injected with 468 nm-sized liposomes exhibited a lower number of inflammatory cells. Still, a greater tissue retention 72 h post-injection was found. Therefore, this study demonstrated the feasibility of the echocardiography-guided percutaneous injection to deliver liposomes successfully into the myocardium in a minimally invasive manner. In addition, these findings indicate the potential of liposomes as carriers of biopharmaceuticals for myocardial delivery, supporting the development of further research on these delivery systems for heart disease.

Microencapsulation of Lactobacillus acidophilus La-05 and incorporation in vegan milks: Physicochemical characteristics and survival during storage, exposure to stress conditions, and simulated gastrointestinal digestion.

The effect of microencapsulation of L. acidophilus La-05 (8 log CFU/mL) by external ionic gelation technique in alginate (30 g/L; AM) and alginate coated with a low molecular weight chitosan solution (5 g/L; AC5M) on the survival of the freeze-dried probiotic culture during storage (7 °C; 0, 7, 15, 30, 60, 90 and 120 days), and exposure to temperature (72, 85 and 90 °C), pH (2, 4, and 6), and NaCl (10, 15 and 20 g/L) were studied. Furthermore, vegan milks (soybean and rice milks) added with microencapsulated probiotic cultures were evaluated for the physicochemical characteristics and survival of the probiotic culture during refrigerated storage (7 °C; 7 days) and in vitro digestion. Free cells were used as control. AM and AC5M showed similar microencapsulation yield (>90%) with uniform and spherical microparticles dispersed without agglomeration. Scanning electron microscopy showed that chitosan was able to cover the porous structure of the alginate particles, resulting in a more stabilized microparticle. The microencapsulation provided higher probiotic protection to storage, thermal treatment, NaCl and pH (decreases of ~1 log CFU/mL) compared to the free cells (decreases of ~3, 4, 2 and 3 log CFU/mL, respectively), and increased probiotic survival during refrigerated storage and in vitro digestion of vegan milks compared to free cells (decreases of ~1 and 4 log CFU/mL, respectively). Only microencapsulated probiotic cultures (AM and AC5M) maintained suitable probiotic counts (>6 log CFU/mL) during storage, exposure to stress conditions and simulated gastrointestinal digestion. Chitosan coating increased the probiotic survival in the vegan milks during refrigerated storage. Microencapsulation by external ionic gelation in alginate proved to be a suitable microencapsulation technique to improve the probiotic survival to storage, stress conditions (temperature, pH and NaCl) and simulated gastrointestinal conditions. This was the first study that evaluated the addition of probiotic cultures to rice and soybean milks, proving that the vegan milks could be considered suitable carriers for microencapsulated probiotic cultures.