ß-Caryophyllene nanoparticles design and development: Controlled drug delivery of cannabinoid CB2 agonist as a strategic tool towards neurodegeneration.

The sesquiterpene ß-caryophyllene (BCP) is a structurally singular cannabinoid and a selective agonist of the CB2 receptor, which in addition to being expressed in the CNS, is intrinsically expressed within the immune system and lacks psychoactivity. Nanoencapsulation of BCP can allow its controlled release into the CNS and intranasal administration. Thus, a protocol for nanoencapsulation of BCP was developed and optimized in order to adjust the desired bioactive content and physicochemical parameters. The formulation was assessed regarding nanoparticle size, zeta potential, morphology, pH, osmolarity, stability, and drug release kinetics in vitro. The final composition of the BCP nanoparticles presented in its organic phase (OP) Tween 20 (0.25%), BCP (0.1%), and PEG 400 (5%); and in its aqueous phase (AP) ultrapure water and poloxamer P188 (0.25%). The formulation showed to be suitable for intranasal administration, presenting pH 6.5 and osmolarity of 150 mmol/kg. The mean particle diameter was 147.2 nm, PDI 0.052, and zeta potential of -24.5. The accelerated stability test showed that nanoparticles were stable for up to 1 month, when reversible creaming effect occurred. Besides, it was noted a low rate of particle accumulation and particle size distribution remained unchanged. BCP nanoparticles were shown to be promptly released in physiological medium (up to 60 min). In this work, a formulation containing ß-caryophyllene nanoparticles suitable for physiological administration and preclinical tests was successfully developed.

Development of nanoparticles coated with cassava bagasse pectin (Manihot esculenta Crantz) containing ß-carotene for mucoadhesive applications.

Pectin (PC) extracted from a solid residue from cassava roots (Manihot esculenta Crantz) was used to coat nanoparticles (NP) containing ß-carotene (BC) aiming at the gastrointestinal administration of this lipophilic nutraceutical. The NP were prepared by spontaneous emulsification method using food grade components. Pectin-coated NP have been successfully prepared as confirmed by the increased particle size and negative surface charges due to the pectin's anionic nature. NP showed spherical shape and monodisperse distribution, with a mean size of 21.3 nm (polydispersity index (PDI) 0.29) for BC PC T80-NP (nanoparticle with ß-carotene, pectin and Tween 80) and 261.4 nm (PDI 0.1) for BC PC T20-NP (nanoparticle with ß-carotene, pectin and Tween 20). BC was encapsulated at amounts of 530 and 324 µg/ml for BC PC T80-NP and BC PC T20-NP, respectively, with high encapsulation efficiency (> 95%), increasing its antioxidant capacity in vitro, besides no cytotoxic effect. However, only BC PC T20-NP was stable over a 90 days storage period (4°C) and revealed a strong interaction between pectin and mucin. These results suggest that pectin-coated BC PC T20-NP is a promising strategy to improve the bioavailability and permeation of BC for administration through mucosal surfaces.

Nanotechnology: A Promising Tool Towards Wound Healing.

Nanotechnology is an exciting emerging field with multiple applications in skin regeneration. Nanofibers have gained special attention in skin regeneration based on their structural similarity to the extracellular matrix. A wide variety of polymeric nanofibers with distinct properties have been developed and tested as scaffolds for skin regeneration. Besides providing support for tissue repair, nanofibrous materials can act as delivery systems for drugs, proteins, growth factors, and other molecules. Moreover, the morphology, biodegradability, and other functionalities of nanofibrous materials can be controlled towards specific conditions of wound healing. Other nanostructured drug delivery systems, such as nanoparticles, micelles, nanoemulsions, and liposomes, have been used to improve wound healing at different stages. These nanoscale delivery systems have demonstrated several benefits for the wound healing process, including reduced cytotoxicity of drugs, administration of poorly water-soluble drugs, improved skin penetration, controlled release properties, antimicrobial activity, and protection of drugs against light, temperature, enzymes or pH degradation, as well as stimulation of fibroblast proliferation and reduced inflammation.

Foreign body reaction associated with PET and PET/chitosan electrospun nanofibrous abdominal meshes.

Electrospun materials have been widely explored for biomedical applications because of their advantageous characteristics, i.e., tridimensional nanofibrous structure with high surface-to-volume ratio, high porosity, and pore interconnectivity. Furthermore, considering the similarities between the nanofiber networks and the extracellular matrix (ECM), as well as the accepted role of changes in ECM for hernia repair, electrospun polymer fiber assemblies have emerged as potential materials for incisional hernia repair. In this work, we describe the application of electrospun non-absorbable mats based on poly(ethylene terephthalate) (PET) in the repair of abdominal defects, comparing the performance of these meshes with that of a commercial polypropylene mesh and a multifilament PET mesh. PET and PET/chitosan electrospun meshes revealed good performance during incisional hernia surgery, post-operative period, and no evidence of intestinal adhesion was found. The electrospun meshes were flexible with high suture retention, showing tensile strengths of 3 MPa and breaking strains of 8-33%. Nevertheless, a significant foreign body reaction (FBR) was observed in animals treated with the nanofibrous materials. Animals implanted with PET and PET/chitosan electrospun meshes (fiber diameter of 0.71 ± 0.28 µm and 3.01 ± 0.72 µm, respectively) showed, respectively, foreign body granuloma formation, averaging 4.2-fold and 7.4-fold greater than the control commercial mesh group (Marlex). Many foreign body giant cells (FBGC) involving nanofiber pieces were also found in the PET and PET/chitosan groups (11.9 and 19.3 times more FBGC than control, respectively). In contrast, no important FBR was observed for PET microfibers (fiber diameter = 18.9 ± 0.21 µm). Therefore, we suggest that the reduced dimension and the high surface-to-volume ratio of the electrospun fibers caused the FBR reaction, pointing out the need for further studies to elucidate the mechanisms underlying interactions between cells/tissues and nanofibrous materials in order to gain a better understanding of the implantation risks associated with nanostructured biomaterials.

Nanofibrous poly(3-hydroxybutyrate-co-3-hydroxyvalerate)/chitosan scaffolds for skin regeneration.

The purpose of this study was to evaluate hybrid poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV)/chitosan nanofibrous mats as scaffolds for skin engineering. In vitro studies were carried out to test the potential of the scaffolds for fibroblasts adhesion, viability, and proliferation (L929 cell line). The in vivo performance was also studied in a full-thickness wound healing model. PHBV/chitosan 4:1 (w/w) exhibited a higher in vitro biocompatibility and a better ability for cell adhesion and growth, compared to PHBV/chitosan 2:3 (w/w). The in vivo assay also revealed the better performance of this scaffold, improving the wound healing process in rats.