Regulation of the colon-targeted release rate of lactoferrin by constructing hydrophobic ethyl cellulose/pectin composite nanofibrous carrier and its effect on anti-colon cancer activity.

In order to modify colonic release behavior of lactoferrin (Lf), a hydrophobic composite nanofibrous carrier (CNC) was constructed by emulsion coaxial electrospinning. Ethylcellulose/pectin based water-in-oil emulsion and Lf-contained polyvinyl alcohol solution were used as shell and core fluids, respectively. An electrospinning diagram was first constructed to screen out suitable viscosity (51-82 cP) and conductivity (960-1300 µS/cm) of the dispersed phase of pectin solution for successful electrospinning of shell emulsion. Varying mass fraction of pectin solution (5 %-20 %) of shell emulsion during emulsion coaxial electrospinning obtained CNCs with different micro-structures, labeled as 5&95 CNC, 10&90 CNC, 15&85 CNC, 20&80 CNC. These CNCs all achieved colonic delivery of Lf (>95 %), and the time for complete release of Lf in simulated colon fermentation process were 10, 7, 5 and 3 h, respectively. That is, the greater the pectin content in CNC, the faster the release rate of stabilized Lf in colon. Lf release in simulated colon fermentation fluid involved complex mechanisms, in which diffusion release of Lf was dominant. Increasing colonic release rate of Lf enhanced its regulation effect on the expression levels of cell cycle arrest and apoptosis-related protein and promote its effective inhibition on the proliferation of HCT116 cell.

Improving the bioaccessibility of lipophilic ingredient in its oral intestinal delivery by ultrasound and biological cross-linker.

BACKGROUND: Great efforts have been made to improve the oral bioaccessibility of lipophilic ingredients with multi-functionalities. Achieving intestinal delivery of lipophilic ingredients and their encapsulation in micelles composed of bile salts and lipid hydrolysates (i.e. fatty acids) is critical for improving oral bioaccessibility. Therefore, oil-core microcapsules are considered ideal carriers of lipophilic ingredients. Previous studies have reported oil-core/zein-shell microcapsules constructed by a one-step anti-solvent process. Still, its efficacy as an intestinal delivery system was limited because if the porous shell structure. RESULTS: Zein solution was pretreated with ultrasound and tannic acid (TA) cross-linking. Composite oil-core microcapsule (COM) with a compact shell structure was successfully prepared by using modified zein solution in the anti-solvent process. Fourier-transform infrared spectroscopy and circular dichroism analyses indicated that ultrasound and TA synergistically promote the conformational transition of zein from α-helix to ß-sheet and enhance the hydrophobic interactions among protein chains. The above changes contribute to the strengthen of shell zein network. Correspondingly, COM presents superior encapsulation efficiency and environmental stability over the simple oil-core microcapsule (SOM) prepared without the use of ultrasound and TA. Furthermore, antioxidant activity of ß-carotene was well retained during the encapsulation process. In vitro studies indicated that COM was more resistant to digestibility and acid-induced swelling. More than 87% of ß-carotene could be released in the intestine in a sustainable way. The controllable release behavior thus promoted a significant increase in bioaccessibility of ß-carotene encapsulated in COM compared to SOM (85.9% versus 48.5%). CONCLUSION: The COM generated here shows potential for bioaccessibility improvement of lipophilic ingredients. © 2022 Society of Chemical Industry.

Insights into Protective Effects of Different Synbiotic Microcapsules on the Survival of Lactiplantibacillus plantarum by Electrospraying.

This study evaluated the protective effects of different synbiotic microcapsules on the viability of encapsulated Lactiplantibacillus plantarum GIM1.648 fabricated by electrospraying. The optimum amount of substrate for three synbiotic microcapsules separately containing fructooligosaccharide (FOS), fish oil, and the complex of both were 4% FOS (SPI-F-L-P), 20 µL fish oil (SPI-O-L-P) and the complex of 20 µL fish oil, and 2% FOS (SPI-O-F-L-P), respectively. The obtained synbiotic microcapsules had a better encapsulation efficiency (EE) and survival rate (SR) after in vitro digestion than microcapsules without the addition of substrate (SPI-L-P) and SPI-O-F-L-P presented the highest EE (95.9%) and SR (95.5%). When compared to SPI-L-P, the synbiotic microcapsules possessed a more compact structure as proved by the SEM observation and their cell viability were significantly improved in response to environmental stresses (heat treatment, freeze drying, and storage). The synbiotic microcapsules containing the complex of FOS and fish oil showed the best beneficial effect, followed by ones with fish oil and then FOS, suggesting the FOS and fish oil complex has more potential in application.

Oral fate and stabilization technologies of lactoferrin: a systematic review.

Lactoferrin (Lf), a bioactive protein initially found in many biological secretions including milk, is regarded as the nutritional supplement or therapeutic ligand due to its multiple functions. Research on its mode of action reveals that intact Lf or its active peptide (i.e., lactoferricin) shows an important multifunctional performance. Oral delivery is considered as the most convenient administration route for this bioactive protein. Unfortunately, Lf is sensitive to the gastrointestinal (GI) physicochemical stresses and lactoferricin is undetectable in GI digesta. This review introduces the functionality of Lf at the molecular level and its degradation behavior in GI tract is discussed in detail. Subsequently, the absorption and transport of Lf from intestine into the blood circulation, which is pivotal to its health promoting effects in various tissues, and some assisting labeling methods are discussed. Stabilization technologies aiming at preserving the structural integrity and functional properties of orally administrated Lf are summarized and compared. Altogether, this work comprehensively reviews the structure-function relationship of Lf, its oral fate and the development of stabilization technologies for the enhancement of the oral bioavailability of Lf. The existing limitations and scope for future research are also discussed.

Fabrication of Nano/Micro-Structured Electrospun Detection Card for the Detection of Pesticide Residues.

A novel nano/micro-structured pesticide detection card was developed by combining electrospinning and hydrophilic modification, and its feasibility for detecting different pesticides was investigated. Here, the plain and hydrophilic-modified poly(ε-caprolactone) (PCL) fiber mats were used for the absorption of indolyl acetate and acetylcholinesterase (AChE), respectively. By pre-treating the fiber mat with ethanol, its surface wettability was improved, thus, promoting the hydrolysis of the PCL fiber mat. Furthermore, the absorption efficiency of AChE was improved by almost two times due to the increased hydrophilicity of the modified fiber mat. Noteworthily, this self-made detection card showed a 5-fold, 2-fold, and 1.5-fold reduction of the minimum detectable concentration for carbofuran, malathion, and trichlorfon, respectively, compared to the national standard values. Additionally, it also exhibited good stability when stored at 4 °C and room temperature. The food detection test showed that this nano/micro-based detection card had better detectability than the commercial detection card. Therefore, this study offers new insights into the design of pesticide detection cards, which also broadens the application of electrospinning technique.

Fabrication of nanostructured multi-unit vehicle for intestinal-specific delivery and controlled release of peptide.

An oral multi-unit delivery system was developed by incorporating the nanoparticle (NP) into the nanofiber mat and its efficiency for intestinal-specific delivery and controlled release of a peptide (insulin) was investigated. Initially, the influence of deacetylation degree (DD) of chitosan and ionic gelation methods on the properties of NPs was studied. High DD (95%) chitosan was attributed to higher encapsulation efficiency and stability when crosslinked with polyanion tripolyphosphate. Subsequently, the multi-unit system was fabricated using a pH-sensitive polymer (sodium alginate) as the coating layer to further encapsulate the NP. Fiber mat with an average diameter of 481 ± 47 nm could significantly decrease the burst release of insulin in acidic condition and release most amount of insulin (>60%) in the simulated intestinal medium. Furthermore, the encapsulated peptide remained in good integrity. This multi-unit carrier provides the better-designed vehicle for intestinal-specific delivery and controlled release of the peptide.

A novel Pickering emulsion system as the carrier of tocopheryl acetate for its application in cosmetics.

Pickering emulsion (PE) stabilized by bio-compatible polymer nanoparticles (NPs) was first developed for the encapsulation of lipophilic tocopheryl acetate (TA) for its application in cosmetics. The poly(lactide-co-glycolide) (PLGA)/poly(styrene-co-4-styrene-sulfonate) (PSS) NPs were prepared by solvent displacement, and then they were used as emulsifier particles to fabricate TA-encapsulated PE. It was found that the TA encapsulation efficiency was >98%. Scanning electron microscope analysis showed that the obtained PE exhibited 'shell' structure. The PE droplets had spherical shape with diameter around 2 µm and good dispersibility as evidenced by laser scanning confocal microscope. In addition, the PE was stable at the pH range of 4.29-7.07 which was compatible to skin pH. Meanwhile, the PE also showed good storage stability since there was no obvious change in its diameter, PDI and TA retention after storage at 4 °C for 30 days. The DPPH method confirmed that TA retained its antioxidation in the PE preparation process. Moreover, an improved UV irradiation stability was observed for the TA after being encapsulated in the PE. The results of cytotoxicity test suggested that the PE was compatible to the Hacat cell line (human immortalized keratinocytes). And there is negligible influence in the cellular uptake of TA after its encapsulation in the PE. However, the cellular antioxidant activity (CAA) of encapsulated TA presented a significant increase from 1.32 to 1.56 µM quercetin equivalent/mg·mL-1. Hence, the prepared PE was promising as the carrier of TA for its cosmetic application.

A novel route for double-layered encapsulation of probiotics with improved viability under adverse conditions.

To improve the survivability of probiotics under the harsh conditions, a novel double-layered vehicle, which was developed by a one-step coaxial electrospinning procedure, was here used to encapsulate the probiotics. The morphology characterization analysis revealed that the electrospun fiber had a beaded morphology and core-shell structure. Probiotic cells were successfully encapsulated in the fibers (107 CFU/mg) and exhibited an oriented distribution along the fiber. Additionally, the encapsulation of core-shell fiber mat enhanced the tolerance of probiotic cells to simulated gastrointestinal conditions and no significant loss of viability was found (p > 0.05). Besides that, the encapsulated cells exhibited better thermal stability under heat moisture treatment, lower loss of viability (0.32 log CFU/mL) was occurred when compared with the free cells or encapsulated cells in uniaxial fiber mat. In conclusion, this double-layered vehicle presents a great potential in probiotic encapsulation and improving their resistant ability to the harsh conditions.

Development of a polysaccharide based multi-unit nanofiber mat for colon-targeted sustained release of salmon calcitonin.

Advances in pharmaceutical technology have promoted the development of colon-targeted delivery system for oral administration of bioactive peptides or proteins to enhance their bioavailability. In this study, a multi-unit nanofiber mat was fabricated by coaxial electrospinning and its feasibility as the colon-targeted delivery system for a bioactive peptide, salmon calcitonin (sCT), was investigated. Sodium alginate and sCT-loaded liposome coated with pectin served as the shell layer and core layer, respectively. An in vitro study demonstrated that the encapsulated sCT was released in a sustained and colon-targeted way. Analysis using different mathematical models showed that release followed a complex mechanism. In addition, greater amounts of sCT were released from the core-shell nanofiber mat into simulated colon fluid (SCF) than was released from a uniaxial nanofiber mat (65.2% vs. 47.8%). The use of a core-shell nanofiber mat further alleviated the burst release of sCT into simulated gastric and intestinal fluid (SGF and SIF), demonstrating the superiority of a multi-unit vehicle for colon-targeted delivery of sCT. Furthermore, 88% of the bioactivity of encapsulated sCT was retained. This multi-unit vehicle offers a better-designed vehicle for the colon-targeted sustained release of bioactive peptides or proteins and, thus, should improve oral bioavailability.

Preparation and characterization of an electrospun colon-specific delivery system for salmon calcitonin.

A novel electrospun colon-specific delivery system for salmon calcitonin (SCT) was developed to improve its stability and bioavailability. Firstly, the pectin-coated SCT liposomes were prepared by film dispersion method and then a liposomes/sodium alginate/polyvinyl alcohol fiber mat was fabricated by electrospining. Scanning electron microscopy analysis indicated that the obtained nanofibers were uniform and smooth with an average diameter of about 350 nm. The release of SCT in different simulated digestive fluids was studied and corresponding release kinetics models were built. It was found that the fiber mat containing pectin-coated SCT liposomes had better stability and colon-specific properties compared with that containing uncoated SCT liposomes and the release of SCT in the colon followed the case II transport mechanism. In addition, there is no significant change in the bioactivity of released SCT measured by ELISA. This study shows that the electrospun colon-specific fiber mat is a potential delivery system for bioactive peptides.