This work aimed to develop and evaluate pH-dependent systems based on nanospheres (NSphs) and nanocapsules (NCs) loaded with chlorhexidine (CHX) base as a novel formulation for the treatment of periodontal disease. Cellulose acetate phthalate (CAP) was employed as a pH-dependent polymeric material. The NSphs and NCs were prepared using the emulsion-diffusion technique and then characterized according to encapsulation efficiency (EE), size, zeta-potential, morphology, thermal properties, release profiles and a preliminary clinical panel test. The formulations showed 77% and 61% EE and 57% and 84% process efficiency (PE), respectively. Both systems were spherical with an average size of 250–300 nm. Differential scanning calorimetry (DSC) studies showed that the drug has the potential to be dispersed molecularly in the NSph matrix or dissolved in the oily center of the NCs. The CHX release test revealed that the release of NSphs-CHX follows Fickian diffusion involving diffusion-erosion processes. The NCs showed a slower release than the NSphs, following non-Fickian diffusion, which is indicative of anomalous transport. These nanosystems may, therefore, be employed as novel formulations for treating periodontal disease, due to (1) their coverage of a large surface area, (2) the controlled release of active substances at different pH, and (3) potential gingival tissue infiltration.

The aim of this work was to obtain pH-dependent nanofibers with an electrospinning technique as a novel controlled release system for the treatment of periodontal disease (PD). Cellulose acetate phthalate (CAP) was selected as a pH-sensitive and antimicrobial polymer. The NF was optimized according to polymeric dispersion variables, polymer, and drug concentration, and characterized considering morphology, diameter, entrapment efficiency (EE), process efficiency (PE), thermal properties, and release profiles. Two solvent mixtures were tested, and CHX-CAP-NF prepared with acetone/ethanol at 12% w/v of the polymer showed a diameter size of 934 nm, a uniform morphology with 42% of EE, and 55% of PE. Meanwhile, CHX-CAP-NF prepared with acetone/methanol at 11% w/v of polymer had a diameter of 257 nm, discontinuous nanofiber morphology with 32% of EE, and 40% of PE. EE and PE were dependent on the polymer concentration and the drug used in the formulation. Studies of differential scanning calorimetry (DSC) showed that the drug was dispersed in the NF matrix. The release profiles of CHX from CHX-CAP-NF followed Fickian diffusion dependent on time (t^0.43−0.45), suggesting a diffusion–erosion process and a matrix behavior. The NF developed could be employed as a novel drug delivery system in PD.

Papaya is one of the most consumed fruits in the world; however, tissue damage caused by cuts quickly leads to its decay. Therefore, this study aimed to prepare and characterize lemon oil and curcumin nanocapsules to evaluate their capacity for preserving fresh-cut papaya. Lemon essential oil and curcumin nanocapsules were prepared using ethyl cellulose (EC) and poly-(ε-caprolactone) (PCL) by the emulsification–diffusion method coupled with ultrasound. The particles had sizes smaller than 120 nm, with polydispersity indices below 0.25 and zeta potentials exceeding −12 mV, as confirmed by scanning electron microscopy. The nanoparticles remained stable for 27 days, with sedimentation being the instability mechanism observed. These nanoparticles were employed to coat fresh-cut papaya, which was stored for 17 days. The results demonstrated their remarkable efficacy in reducing the respiration rate. Furthermore, nanocapsules maintained the pH and acidity levels of the papayas for an extended period. The lemon oil/EC nanocapsule treatment retained the color better. Additionally, all systems exhibited the ability to minimize texture loss associated with reduced pectin methylesterase activity. Finally, the nanocapsules showed a notable reduction in polyphenol oxidase activity correlating with preserving total phenolic compounds in the fruit. Therefore, the lemon oil and curcumin nanoparticles formed using EC and PCL demonstrated their effectiveness in preserving fresh-cut ‘Maradol’ papaya.

Background and Aim: Bovine mastitis remains one of the most economically significant diseases in dairy production and is a major driver of antimicrobial usage. The increasing prevalence of antimicrobial resistance has necessitated the development of alternative therapeutic strategies. Essential oils (EOs) and nanotechnology-based delivery systems have emerged as promising non-antibiotic approaches. This study aimed to develop chitosan nanocapsules (NC) co-loaded with tea tree oil (TTO) and thymol, and to evaluate their physicochemical characteristics, cytocompatibility, pH-responsive release behavior, and in vitro antibacterial activity against mastitis-associated pathogens. Materials and Methods: Chitosan NC containing TTO and thymol were prepared using the ionic gelation method. Physicochemical properties were assessed by dynamic light scattering, scanning electron microscopy, and zeta potential analysis. Cytotoxicity was evaluated using MARC-145 cells. In vitro release studies were performed under simulated bovine mammary pH conditions (pH 6.6 and 7.2). Antibacterial activity was tested against Escherichia coli and Staphylococcus aureus using growth kinetics assays. Results: The NC exhibited a mean particle size of 383.1 ± 10.2 nm, a polydispersity index of 0.20, and a positive zeta potential of 24.7 ± 1.3 mV, indicating good stability. Encapsulation efficiency reached 77.5 ± 2.3%. Cytotoxicity analysis showed improved cell viability for nanoformulations compared with free oils, particularly for nanoemulsions. Release studies demonstrated a clear pH-dependent behavior, with limited release at pH 6.6 (18.4%) and enhanced release at pH 7.2 (61.7%) over 70 h. Antibacterial assays revealed that chitosan NC achieved the highest inhibitory effect, reducing S. aureus and E. coli growth by 92% and 72%, respectively. The antibacterial activity against S. aureus was comparable to erythromycin under the tested conditions. Conclusion: Chitosan NC co-loaded with TTO and thymol demonstrated enhanced antibacterial activity, controlled-release, and improved cytocompatibility under in vitro conditions. The pH-responsive release profile highlights their potential as a targeted intramammary delivery system for mastitis management. These findings support further in vivo investigations to validate their applicability as a non-antibiotic alternative in dairy production systems. Keywords: antibacterial activity, bovine mastitis, chitosan nanocapsules, essential oils, ionic gelation, nanotechnology, pH-responsive release, thymol, tea tree oil.

The aim of this study was to develop and characterize C-phycocyanin/whey protein isolate-zein nanoparticles (NPs C-PC/WPI-zein) using the pH-shifting method. Additionally, molecular interactions and changes in the secondary structure of proteins were analyzed using Fourier Transform Infrared (FTIR) spectroscopy. The results showed that the pH-shifting method promotes interactions between proteins, leading to the formation of stable submicrometric systems with an encapsulation efficiency of C-phycocyanin (C-PC) of approximately 70% and a spherical morphology. FTIR analysis revealed that hydrophobic interactions, hydrogen bonding, and electrostatic interactions engage in nanoparticle formation. Moreover, modifications in the secondary structure of the proteins were observed, characterized by an increase in intramolecular β-sheets content and a decrease in α-helices, suggesting effective integration of C-PC into the nanoparticles. These findings support the potential of C-PC/WPI-zein NPs for applications in the pharmaceutical, cosmetic, and food industries.