Preparation and characterization of tea tree oil-β-cyclodextrin microcapsules with super-high encapsulation efficiency

This study aimed to prepare tea tree oil-β-cyclodextrin microcapsules using an optimized co-precipitated method.The impact of the volume fraction of ethanol in the solvent system for microencapsulation on encapsulation efficiency was investigated and analyzed sophisticatedly.Super-high encapsulation efficiency was achieved when a 40%volume fraction of ethanol was used for the microencapsulation procedure,where the recovery yield of microcapsules and the embedding fraction of tea tree oil in microcapsules were as high as 88.3%and 94.3%,respec-tively.Additionally,considering the operation cost,including time and energy consumption,an economical preparation was validated so that it would be viable for large-scale production.Based on the results of morphological and X-ray diffraction analysis,the crystal structure appeared to differ before and after microencapsulation.The results of gas chromatography-mass spectrometry and Fourier transform infrared spectroscopy confirmed the successful formation of microcapsules.Furthermore,the antibacterial activity of the fabricated microcapsules was assessed by a simple growth inhibition test using Bacillus subtilis as the study object,and the hydrophilic property was proved by a water contact angle measurement.

Structure,bioavailability and physicochemical properties of icariin-soymilk nanoparticle

Soymilk is a natural nanocarrier.However,the performance of flavonoid-soymilk nano-complex remains unclear.In this work,icariin-soymilk nano-complexes(ISNCs)were successfully fabricated and characterized.The effects of high-pressure homogenization(HPH)treatment on structure and physicochemical properties of soymilk and nano-complexes were investigated.HPH treatment could significantly improve the surface hydrophobicity and interfacial activity of soymilk.The soymilk with HPH treatment could significantly improve the water solubility(20 folds),thermal stability and bioavailability of icariin.The highest encapsulation efficiency(93.28%),loading capacity(39.09μg/mg),ζ-potentia(absolute value,31.20 mV)and bioavailability(72.14%)were observed in HSI-200(200 bar of homogenization pressure).While HSI-500(500 bar of homogenization pressure)showed the smallest particle size(183.73 nm).ISNCs showed a rougher surface and an irregular lamellar structure with large amount of fine particles by using Cryo-SEM,suggesting that icariin was encapsulated in soymilk.These data supplied a novel strategy to improve the performance of icariin in functional foods.

Encapsulation in the Food Industry: A Brief Historical Overview to Recent Developments

Encapsulation in food industry serves several functions including masking of undesirable color/flavor/taste, preservation of unstable constituents, incorporation of additional functional and nutritional components and site-specific release of encapsulated ingredients at a controlled time and rate. The knowledge of microencapsulation in other sectors like pharmaceutical industry is well advanced;however, more understanding is required to harvest the maximum benefits from food industry. This paper started with highlighting the gradual progress of microencapsulation process in food industry and ended up with some invaluable suggestions for future works. In the body, the paper reviews the major techniques of food encapsulation, choices of coating materials and the performance measurement methods of food encapsulation. Future trends, scopes and aspects of microencapsulation process in food manufacturing sector are also presented as the necessary recommendations for future researches. The article would help the microencapsulated food manufacturers to choose the target oriented encapsulates and suitable encapsulation technique.

Nanoencapsulation of Thymol and Eugenol with Chitosan Nanoparticles and the Effect against <i>Ralstonia solanacearum</i>

Essential oils (EOs) are natural bioactive compounds with antibacterial activity against a variety of microorganisms including phytopathogens. The use of EOs and their components as viable therapeutic antibacterials is however greatly compromised by their volatile nature, hydrophobicity and instability when exposed to environmental and physiological factors. Encapsulation of these compounds in an appropriate carrier system can alleviate these challenges. This study therefore aimed at developing, characterizing and evaluating the efficacy of antibacterial potential of thymol and eugenol loaded chitosan nanoparticles (TCNPs and ECNPs) against Ralstonia solanacearum, the bacterial wilt-causing pathogen in potatoes. Synthesis of TCNP and ECNP was achieved via ionic gelation method and the prepared nanoparticles characterized by their particle size distributions, encapsulation efficiency, loading capacity (LC) and in-vitro release characteristics. Antibacterial activities of the nanoparticles were investigated using agar dilution and colony counting methods and their minimum inhibitory concentration (MIC) determined by 96-well broth micro-dilution method. Scanning electron microscope images of TCNPs and ECNPs showed that the nanoparticles were spherical in shape and were well separated with an average particle size of 590 nm and 555 nm respectively. The average size of chitosan nanoparticles alone was however 375 nm. The encapsulation efficiency was 72.9% for TCNP (with 48.3% LC) and 71.7% for ECNP (with 49.5% LC). The release of thymol and eugenol from the microcapsules was found to be pH dependent with the highest release at pH 1.5. The growth inhibition of R. solanacearum was 92% and 94% for TCNP and ECNPs respectively. The MIC of thymol and eugenol before encapsulation was 175 μg/ml and 275 μg/ml respectively, but this reduced significantly to 22.5 μg/ml and 45 μg/ml after encapsulation. Thus, encapsulation of thymol and eugenol in chitosan nanoparticles has shown promising potential as a bactericide alternative for R. solanacearum and could be useful in managing the soil borne phytopathogen.

Preparation and in vitro Release Properties of Mercaptopurine Drug-loaded Magnetic Microspheres

Magnetic Fe304 nanoparticles were synthesized by co-precipitation method and the mercaptopurine （MER） drug-loaded magnetic microspheres were obtained through emulsion cross-linking methods. The efficiency of this approach was evaluated in terms of drug loading content （DLC）, encapsulation efficiency （EE） and delivery properties in vitro, determined by high performance liquid chromatograph （HPLC）. The microspheres showed good DLC values of 11.8%, as well as good EE values of 79.4%. The in vitro drug release study was carried out in phosphate buffer solution （PBS） simulated body fluid, at 37 ~C with pH=7.4. The release profiles showed an initial fast release rate, which decreased as time progressed and about 84 % had been released after 48 h. The experimental results indicated that the prepared magnetic microspheres may be useful for potential applications of MER for magnetically targeted chemotherapy.

Non-viral liposome-mediated transfer of brain-derived neurotrophic factor across the blood-brain barrier

Brain-derived neurotrophic factor（BDNF） plays an important role in the repair of central nervous system injury,but cannot directly traverse the blood-brain barrier.Liposomes are a new type of non-viral vector,able to carry macromolecules across the blood-brain barrier and into the brain.Here,we investigate whether BDNF could be transported across the blood-brain barrier by tail-vein injection of liposomes conjugated to transferrin（Tf） and polyethylene glycol（PEG）,and carrying BDNF modified with cytomegalovirus promoter（pC MV） or glial fibrillary acidic protein promoter（p GFAP）（Tf-p CMV-BDNF-PEG and Tf-p GFAP-BDNF-PEG,respectively）.Both liposomes were able to traverse the blood-brain barrier,and BDNF was mainly expressed in the cerebral cortex.BDNF expression in the cerebral cortex was higher in the Tf-p GFAP-BDNF-PEG group than in the Tf-p CMV-BDNF-PEG group.This study demonstrates the successful construction of a non-virus targeted liposome,Tf-p GFAP-BDNF-PEG,which crosses the blood-brain barrier and is distributed in the cerebral cortex.Our work provides an experimental basis for BDNF-related targeted drug delivery in the brain.

A partition-type tubular scaffold loaded with PDGF-releasing microspheres for spinal cord repair facilitates the directional migration and growth of cells

The best tissue-engineered spinal cord grafts not only match the structural characteristics of the spinal cord but also allow the seed cells to grow and function in situ.Platelet-derived growth factor（PDGF） has been shown to promote the migration of bone marrow stromal cells;however,cytokines need to be released at a steady rate to maintain a stable concentration in vivo.Therefore,new methods are needed to maintain an optimal concentration of cytokines over an extended period of time to effectively promote seed cell localization,proliferation and differentiation.In the present study,a partition-type tubular scaffold matching the anatomical features of the thoracic 8–10 spinal cord of the rat was fabricated using chitosan and then subsequently loaded with chitosan-encapsulated PDGF-BB microspheres（PDGF-MSs）.The PDGF-MS-containing scaffold was then examined in vitro for sustained-release capacity,biocompatibility,and its effect on neural progenitor cells differentiated in vitro from multilineage-differentiating stress-enduring cells（MUSE-NPCs）.We found that pre-freezing for 2 hours at-20°C significantly increased the yield of partition-type tubular scaffolds,and 30 μL of 25% glutaraldehyde ensured optimal crosslinking of PDGF-MSs.The resulting PDGF-MSs cumulatively released 52% of the PDGF-BB at 4 weeks in vitro without burst release.The PDGF-MS-containing tubular scaffold showed suitable biocompatibility towards MUSE-NPCs and could promote the directional migration and growth of these cells.These findings indicate that the combination of a partition-type tubular scaffold,PDGF-MSs and MUSENPCs may be a promising model for the fabrication of tissue-engineered spinal cord grafts.

Synthesis and thermal properties of nanoencapsulation of paraffin as phase change material for latent heat thermal energy storage

In this work,a series of nanoencapsulated phase change materials(NanoPCMs)with paraffin wax(PW)as core and melamine-formaldehyde(MF)as shell were synthesized by the in-situ polymerization method.The morphol-ogy,chemical structure and thermal properties of prepared NanoPCMs were characterized by scanning electron microscope,Fourier transform infrared,differential scanning calorimetry and thermogravimertic analyzer.The results show that the PW is successfully encapsulated in the MF without chemical interaction,and the NanoPCMs present regular spherical shape with the average diameter of 260-450 nm.The encapsulation efficiency of the NanoPCMs increases with the augment of the supplied amount of core material.The maximum encapsulation efficiency of the NanoPCMs can reach up to approximately 75%.The NanoPCMs can maintain excellent thermal reliability and stability after 2000 thermal cycling.The prepared NanoPCMs can be well applied in the latent heat thermal energy storage and thermal management systems due to their remarkable encapsulation efficiency and thermal properties enable them to.

Lipid carriers for mRNA delivery

Messenger RNA(mRNA)is the template for protein biosynthesis and is emerging as an essential active molecule to combat various diseases,including viral infection and cancer.Especially,mRNA-based vaccines,as a new type of vaccine,have played a leading role in fighting against the current global pandemic of COVID-19.However,the inherent drawbacks,including large size,negative charge,and instability,hinder its use as a therapeutic agent.Lipid carriers are distinguishable and promising vehicles for mRNA delivery,owning the capacity to encapsulate and deliver negatively charged drugs to the targeted tissues and release cargoes at the desired time.Here,we first summarized the structure and properties of different lipid carriers,such as liposomes,liposome-like nanoparticles,solid lipid nanoparticles,lipid-polymer hybrid nanoparticles,nanoemulsions,exosomes and lipoprotein particles,and their applications in delivering mRNA.Then,the development of lipid-based formulations as vaccine delivery systems was discussed and highlighted.Recent advancements in the mRNA vaccine of COVID-19 were emphasized.Finally,we described our future vision and perspectives in this field.

A Detailed View of PLGA-m PEG Microsphere Formation by Double Emulsion Solvent Evaporation Method

PLGA, m PEG diblock copolymer was synthesized by bulk ring-opening polymerization method. The double emulsion solvent evaporation method was used to prepare bovine serum albumin（BSA）-loaded microspheres. Optical microscopy was used to observe the whole microsphere fabrication process. It is confirmed that the proportion of inner aqueous phase is one of the most critical factors that determines the morphology of microspheres. Double emulsion droplets which have appropriate amount of inner aqueous phase can form closed and dense microspheres, while, too much inner aqueous phase will cause a collapse of the double emulsion droplets, resulting in a loss of drug. The proportion of inner aqueous phase was varied to prepare microspheres of different morphology. The results show that with increasing the amount of inner aqueous phase, a higher percent of broken microspheres and lower encapsulation efficiency appeared, and also, a more severe initial burst release and faster release rate.

Effect of different combinations of emulsifier and wall materials on physical properties of spray-dried microencapsulated swida wilsoniana oil

Spray drying was used to produce microencapsulated Wilson’s dogwood(Swida wilsoniana)oil.The influences of the emulsifier and wall materials on the encapsulation were studied in order to produce high quality encapsulated S.wilsoniana oil.The emulsions were prepared by using lecithin(L)and Tween 80(T)with different hydrophilic-lipophilic balance.Results indicated that the stable emulsion was obtained using T and L as the compound emulsifier at a ratio of 4/6(w/w).By virtue of the compound emulsifier(T/L 4/6),the microencapsulation efficiency(MEE)reached 91%,and the oil loading up to 35%was achieved.We also examined the influence of the wall materials on the microencapsulation of S.wilsoniana oil.All the three wall materials exhibited high MEE(>85%),and the highest MEE(95.20%)was obtained with sodium caseinate/lactose.All the S.wilsoniana oil encapsulated with the three wall materials exhibited nearly spherical microcapsules without pores or cracks,thus protecting the oil from oxygen.

Extraction of protein from churpi of yak milk origin:Size reduction,nutraceutical potential and as a wall material for resveratrol

Resveratrol is a known anti-oxidant and anti-cancer bioactive.The low bioavailability and poor water solubility of resveratrol is a major barrier that restricts its usage in food applications.To overcome these problems,the study presents micro and nano encapsulation of resveratrol in casein micelles extracted from Himalayan cheese(Churpi).Resveratrol loaded casein microparticles(CS-rm)were obtained using emulsion-freeze drying.Whereas,resveratrol loaded casein nanoparticles(CS-rn)were obtained using ultrasonication.Both were characterized using dynamic light scattering(DLS),scanning electron microscopy(SEM)and attenuated total reflectance-fourier transform infrared spectroscopy(ATR-FTIR).DLS revealed hydrodynamic diameter of 71.24μm and 387.023 nm and zeta potential of-22.62 and-28.08 mV for CS-rm and CS-rn.FTIR confirmed the characteristic peaks of resveratrol at 965.4,1380.86,1586.66 and 1607 cm-1 confirmed successful micro and nanoencapsulation.CS-rm displayed high encapsulation efficiency(52.32%)and swelling power(77.90 at pH 3 and 68.65 at pH 7.5)than CS-rn.Both micro and nanoencapsulation protected resveratrol in gastric conditions,however,CS-rn showed high release of resveratrol then CS-rm in simulated intestinal conditions.The anti-oxidant and anti-cancer activity of resveratrol under simulated gastric and intestinal conditions(SGID)was significantly higher(p≤0.05)for CS-rn,showing that nanoencapsulation improved release and nutraceutical profile of resveratrol.Resveratrol loaded nano and micro casein particles can be used a source of fortified protein supplement in growing food and nutraceutical industry.