Microfluidic Strategies for Encapsulation, Protection, and Controlled Delivery of Probiotics.

Probiotics are indispensable for maintaining the structure of gut microbiota and promoting human health, yet their survivability is frequently compromised by environmental stressors such as temperature fluctuations, pH variations, and mechanical agitation. In response to these challenges, microfluidic technology emerges as a promising avenue. This comprehensive review delves into the utilization of microfluidic technology for the encapsulation and delivery of probiotics within the gastrointestinal tract, with a focus on mitigating obstacles associated with probiotic viability. Initially, it elucidates the design and application of microfluidic devices, providing a precise platform for probiotic encapsulation. Moreover, it scrutinizes the utilization of carriers fabricated through microfluidic devices, including emulsions, microspheres, gels, and nanofibers, with the intent of bolstering probiotic stability. Subsequently, the review assesses the efficacy of encapsulation methodologies through in vitro gastrointestinal simulations and in vivo experimentation, underscoring the potential of microfluidic technology in amplifying probiotic delivery efficiency and health outcomes. In sum, microfluidic technology represents a pioneering approach to probiotic stabilization, offering avenues to cater to consumer preferences for a diverse array of functional food options.

Core-shell nanofibers based on microalgae proteins/alginate complexes for enhancing survivability of probiotics.

In this study, a novel one-step coaxial electrospinning process is employed to fabricate shell-core structure fibers choosing Chlorella pyrenoidosa proteins (CP) as the core material. These nanofibers, serving as the wall material for probiotic encapsulation, aimed to enhance the stability and antioxidant activity of probiotics in food processing, storage, and gastrointestinal environments under sensitive conditions. Morphological analysis was used to explore the beads-on-a-string morphology and core-shell structure of the electrospun fibers. Probiotics were successfully encapsulated within the fibers (7.97 log CFU/g), exhibiting a well-oriented structure along the distributed fibers. Compared to free probiotics and uniaxial fibers loaded with probiotics, encapsulation within microalgae proteins/alginate core-shell structure nanofibers significantly enhanced the probiotic cells' tolerance to simulated gastrointestinal conditions (p < 0.05). Thermal analysis indicated that microalgae proteins/alginate core-shell structure nanofibers displayed superior thermal stability compared to uniaxial fibers. The introduction of CP resulted in a 50 % increase in the antioxidant capacity of probiotics-loaded microalgae proteins/alginate nanofibers compared to uniaxial alginate nanofibers, with minimal loss of viability (0.8 log CFU/g) after 28 days of storage at 4 °C. In summary, this dual-layer carrier holds immense potential in probiotic encapsulation and enhancing their resistance to harsh conditions.

Microfluidic fabrication of core-shell fucoxanthin nanofibers with improved environmental stability for reducing lipid accumulation in vitro.

Fucoxanthin is a xanthophyll carotenoid that possesses potent antioxidant, anti-obesity, and anti-tumor properties. However, its limited solubility in water and susceptibility to degradation create challenges for its application. In this study, a microfluidic coaxial electrospinning technique was used to produce core-shell zein-gelatin nanofibers for encapsulating fucoxanthin, enhancing its bioavailability, and improving its stability. In comparison to uniaxially-loaded fucoxanthin nanofibers, the encapsulation efficiency of fucoxanthin reached 98.58 % at a core-shell flow rate ratio of 0.26:1, representing a 14.29 % improvement. The photostability of the nanofibers increased by 74.59 % after three days, UV stability increased by 38.82 % after 2 h, and temperature stability also significantly improved, demonstrating a protective effect under harsh environmental conditions (P < 0.05). Additionally, nanofibers effectively alleviated oleic acid-induced reactive oxygen species production and reduced fluorescence intensity by 54.76 %. MTT experiments indicated great biocompatibility of the nanofibers, effectively mitigating mitochondrial membrane potential polarization and lipid accumulation in HepG2 cells. Overall, the microfluidic coaxial electrospinning technique enables promising applications of fucoxanthin delivery in the food industry.

Incorporation of fucoxanthin into 3D printed Pickering emulsion gels stabilized by salmon by-product protein/pectin complexes.

The remarkable performance of fucoxanthin (FX) in antioxidant and weight loss applications has generated considerable interest. However, the application of fucoxanthin in the food and pharmaceutical industries is limited due to its highly unsaturated structure. This research aimed to investigate the synergistic mechanism of a unique Pickering emulsion gel stabilized by salmon byproduct protein (SP)-pectin (PE) aggregates and evaluate its ability to enhance the stability and bioavailability of FX. Various analytical techniques, including fluorescence spectroscopy, contact angle testing, turbidity analysis, and cryo-field scanning electron microscopy, were used to demonstrate that electrostatic and hydrophobic interactions between SP and PE contribute to the exceptional stability and wettability of the Pickering emulsion gels. Rheological analysis revealed that increasing the concentration of SP-PEs resulted in shear-thinning behavior, excellent thixotropic recovery performance, higher viscoelasticity, and good thermal stability of the Pickering emulsion gels stabilized by SP-PEs(SEGs). Furthermore, encapsulation of FX in the gels showed protected release under simulated oral and gastric conditions, with the subsequent controlled release in the intestine. Compared to free FX and the control group without PE (SEG-0), SEG-4 exhibited a 1.92-fold and 1.37-fold increase in the total bioavailable fraction of FX, respectively. Notably, during the study, it was observed that SEGs have the potential to serve as cake decoration for 3D printing to replace traditional cream under lower oil phase conditions (50%). These findings suggest that SP-PEs-stabilized Pickering emulsion gels hold promise as carriers for delivering bioactive compounds, offering the potential for various innovative food applications.

Survivability of probiotics in Pickering emulsion gels stabilized by salmon by-product protein / sodium alginate soluble complexes at neutral pH.

Adequate amounts of live probiotics reaching the gut are necessary to maintain host health. However, the harsh environment during processing, the low pH of human gastric acid, and the high concentration of bile salts in the gut can significantly reduce survivability of probiotics. In this work, we propose a simple Pickering emulsion gels strategy to encapsulate Lactobacillus plantarum Lp90 into oil droplets filled in calcium alginate gels to improve its viability under pasteurization and gastrointestinal conditions. The emulsion gels were stabilized by the soluble complexes of salmon by-product protein (SP) and sodium alginate (ALG), and the aqueous phase was solidified by the addition of calcium. The interaction between SP and ALG and the effect of ALG concentration on emulsifying ability and emulsion stability were studied. The results from optical imaging, nuclear magnetic resonance, and rheological properties showed that the stability and viscosity of the emulsions gradually increased with the increased ALG concentration, while the droplet size of the emulsions and the content of free water in the system decreased significantly. Especially when the concentration of ALG was 1 %, the emulsion system was stable under the environment of high temperature and high ionic strength, and the water holding capacity was the highest. Through pasteurization and gastrointestinal digestion experiments, it was found that the survival rate of probiotics encapsulated in emulsion gels was significantly higher than that encapsulated in emulsions or hydrogels, which benefited from the dual action of oil droplets and calcium alginate gels network. These results provide a new strategy for the processing of probiotics and the high-value utilization of marine fish by-products.

On-Chip Precisely Controlled Preparation of Uniform Core-Shell Salmon Byproduct Protein/Polysaccharide Microcapsules for Enhancing Probiotic Survivability in Fruit Juice.

The increasing demand for probiotic-fortified fruit juices stems from the dietary requirements of individuals with dairy allergies, lactose intolerance, and vegetarian diets. However, a notable obstacle arises from the degradation of probiotics in fruit juices due to their low pH levels and harsh gastrointestinal conditions. In response, this study proposes an innovative approach utilizing a microfluidic chip to create core-shell microcapsules that contain Lactobacillus plantarum Lp90. This method, based on internal-external gelation, forms highly uniform microcapsules that fully enclose the core, which consists of oil-in-water Pickering emulsions stabilized by salmon byproduct protein and sodium alginate. These emulsions remain stable for up to 72 h at a 1% sodium alginate concentration. The shell layer incorporates kelp nanocellulose and sodium alginate, thus improving the thermal properties. Furthermore, compared to free probiotics, the multilayer structure of the core-shell microcapsules provides a robust barrier, resulting in significantly enhanced probiotic stability. These findings introduce a novel strategy for augmenting probiotic delivery in functional fruit juice beverages, promising solutions to the challenges encountered during their development.

Size-controllable food-grade nanoparticles based on sea cucumber polypeptide with good anti-oxidative capacity to prolong lifespan in tumor-bearing mice.

Liver cancer, a malignancy with a rising global incidence, poses a significant challenge in achieving effective treatment outcomes. As food-derived nutrient, sea cucumber peptide (SCP) has shown promising anticancer effects. Therefore, we explored the nanodelivery systems to encapsulate SCP to enhance its stability in the gastrointestinal tract and improve absorption within the tumor microenvironment. This study aimed to develop size-controllable multifunctional nanoparticles using SCP, procyanidins (PCs), and vanillin through molecular assembly via a one-pot Mannich condensation approach. These food-grade nanoparticles demonstrated water solubility and exhibited a spherical structure with sizes ranging from 441 to 1360 nm, depending on the concentration of the reactants. In vitro cell experiments demonstrated that SCP nanoparticles modified with PCs effectively reduced the generation of reactive oxygen species from H2O2 and acrylamide while maintaining normal levels of mitochondrial membrane potential. Furthermore, in vivo nutrition intervention studies conducted on tumor-bearing mice revealed that mice treated with SCP nanoparticles exhibited a survival rate of 40 %, which was significantly higher than the 0 % and 20 % survival rates observed in the control and SCP-treated groups, respectively. These findings suggest that SCP nanoparticles, possessing antioxidative properties and controllable sizes, hold potential for precision nutrition in the field of cancer treatment.

Pickering emulsions stabilized by Chlorella pyrenoidosa protein-chitosan complex for lutein encapsulation.

Lutein has many physiological functions like antioxidation, anti-cancer, and anti-inflammation, which presents good potential in the development of functional food for eye protection. However, the hydrophobicity and harsh environment factors during digestive absorption process will greatly reduce lutein bioavailability. In this study, Chlorella pyrenoidosa protein-chitosan complex stabilized Pickering emulsions were prepared, and lutein was encapsulated into corn oil droplets to increase its stability and bioavailability in gastrointestinal digestion. The interaction between Chlorella pyrenoidosa protein (CP) and chitosan (CS), and the effect of chitosan concentration on the emulsifying ability of the complex and emulsion stability were studied. With the increase of CS concentration from 0% to 0.8%, the emulsion droplet size obviously decreased, and the emulsion stability and viscosity increased significantly. In particular, when the concentration was 0.8%, the emulsion system was stable at 80 °C and 400 mM sodium chloride. After ultraviolet irradiation for 48 h, the retention rate of lutein encapsulated in Pickering emulsions was 54.33%, which was significantly higher than that (30.67%) of lutein dissolved in corn oil. The retention rate of lutein in Pickering emulsions stabilized by CP-CS complex was significantly higher than that in Pickering emulsions stabilized by CP only and corn oil after heating at 90 °C for 8 h. The results of simulated gastrointestinal digestion showed that the bioavailability of lutein encapsulated in Pickering emulsions stabilized by CP-CS complex reached 44.83%. These results explored the high-value utilization of Chlorella pyrenoidosa and provided new insights into the preparation of Pickering emulsions and the protection for lutein.

Survivability of probiotics encapsulated in kelp nanocellulose/alginate microcapsules on microfluidic device.

Probiotics are living microorganisms that can produce health benefits to the host only when they are ingested in sufficient quantities and reach the intestines active state. However, the external environment that probiotics face for a long time before administration and the low pH environment in the stomach after administration can greatly reduce their activity. In this work, we proposed a simple microfluidic encapsulation strategy to efficiently prepare the probiotics-loaded nanocellulose/alginate delivery system, which can improve the storage stability and gastrointestinal survival rate of probiotics. The microcapsules were found to be monodisperse, and the average particle size was<500 µm by observing the microstructure and macroscopic morphology. The kelp nanocellulose was cross-linked in the microcapsule and formed a dense surface with alginate. Through the simulated gastrointestinal digestion experiment, it was found that the survival of probiotics in microcapsules containing 0.5 % and 1.5 % kelp nanocellulose decreased by 1.77 log CFU/g and 1.65 log CFU/g respectively, which was significantly lower than that of nanocellulose-free microcapsules (3.70 log CFU/g). And all the treated groups could release probiotics above 7 log CFU/g after digesting intestinal juice for 6 h. Furthermore, through the storage experiment, it was found that the microcapsules with 1.5 % kelp nanocellulose could still release 8.07 log CFU/g probiotics after four weeks. The results provide a new strategy for probiotics processing and extensive high-value utilization of marine natural products.

Features of 921 Patients With Spinal Tuberculosis: A 16-Year Investigation of a General Hospital in Southwest China.

Southwest China has a high burden of spinal tuberculosis (TB). Few large case studies of spinal TB in southwest China have been conducted. This study investigated the features of 921 patients who were treated for spinal TB at a general hospital in southwest China between 2001 and 2016. Demographic data, clinical data, laboratory data, imaging findings, treatment methods, and outcomes of patients who were admitted to the hospital for spinal TB were reviewed retrospectively. The annual incidence of spinal TB increased throughout the study period. The greatest number of patients were 41 to 50 years old (22.04%). Local pain was the most common symptom (97.8%). A significant difference in the duration of symptoms was observed between rural populations (28.40 months) and urban populations (10.17 months) (P=.041). Of the patients, 32.68% had a normal erythrocyte sedimentation rate and 25.84% had a normal C-reactive protein level. The lumbar spine was the most commonly involved spinal site (44.77%), followed by the thoracic spine (43.60%). All of the patients underwent chemotherapy, and 77.10% of patients underwent surgery. Most of the patients were cured, with the exception of 2.19% of patients who discontinued chemotherapy after early improvement of clinical status. Spinal TB is still a major public health problem in southwest China. Chemotherapy and surgery can yield satisfactory outcomes with timely diagnosis and long-term treatment. It is urgent to increase the attention paid to spinal TB and improve knowledge of this disease among the general public, especially in southwest China. [Orthopedics. 2017; 40(6):e1017-e1023.].

[Strategies of closed reduction in treatment of femoral neck fracture using cannulated screw fixation].

OBJECTIVE: To study intraoperative reduction strategy in treatment of femoral neck fracture using cannulated screw fixation and the relationship between excellent and good rate of reduction and postoperative effectiveness. METHODS: A retrospective analysis was made on the clinical data of 174 cases of femoral neck fracture treated between August 2005 and March 2015. There were 78 males and 96 females with an average age of 53.8 years (range, 23-75 years). The injury causes were falling in 85 cases, traffic accident in 61 cases, and falling from height in 28 cases. According to Garden typing, there were 35 cases of type I, 56 cases of type Ⅱ, 47 cases of type Ⅲ, and 36 cases of type Ⅳ. The time from injury to operation was 1-7 days (mean, 2.74 days). Based on reduction strategy, closed 3 hollow compression screws were used; evaluating standards for fracture reduction effect were also established. Harris score was used for effectiveness evaluation. RESULTS: All the cases received follow-up of 12-42 months (mean, 36.5 months). Bone healing was obtained in 152 cases at 6-12 months (mean, 9 months). Non-union and internal fixation failure occurred in 9 and 3 patients respectively, who underwent hemiarthroplasty; femoral head necrosis occurred in 6 patients after removing internal fixator at 15-26 months (mean, 18.5 months) after operation, who underwent total hip arthroplasty; 4 patients with non-union received vascular pedicle iliac flap transplantation. No other serious complications were observed. At last follow-up, the excellent and good rate of reduction was 94.29% for Garden type I, 91.07% for type Ⅱ, 87.23% for type Ⅲ, and 75.00% for type Ⅳ, with a total excellent and good rate of 87.36%; the excellent and good rate of Harris score was 97.14% for Garden type I, 78.57% for type Ⅱ, 68.09% for type Ⅲ, and 50.00% for type Ⅳ, with a total excellent and good rate of 73.56%. CONCLUSIONS: To obtain high Harris score in fixation of femoral neck fractures by using hollow screws, surgeons not only need reasonable technology, but also follow correct and good reduction strategy and assessment,fracture complexity is inversely proportional to excellent and good rate of reduction. Higher excellent and good reduction rate of complexity fracture should be obtained as much as possible in order to achieve good prognosis.