Facile preparation of artemisia argyi oil-loaded antibacterial microcapsules by hydroxyapatite-stabilized Pickering emulsion templating

Nanoparticle-Empowered Core-Shell Microcapsules: From Architecture Design to Fabrication and Functions

Compartmentalization is a powerful concept to integrate multiscale components with diverse functionalities into miniature architectures. Inspired by evolution-optimized cell compartments, synthetic core-shell capsules enable storage of actives and on-demand delivery of programmed functions, driving scientific progress across various fields including adaptive materials, sustainable electronics, soft robotics, and precision medicine. To simultaneously maximize structural stability and environmental sensitivity, which are the two most critical characteristics dictating performance, diverse nanoparticles are incorporated into microcapsules with a dense shell and a liquid core. Recent studies have revealed that these nano-additives not only enhance the intrinsic properties of capsules including mechanical robustness, optical behaviors, and thermal conductivity, but also empower dynamic features such as triggered release, deformable structures, and fueled mobility. In this review, the physicochemical principles that govern nanoparticle assembly during microencapsulation are examined in detail and the architecture-controlled functionalities are outlined. Through the analysis of how each primary method implants nanoparticles into microcapsules, their distinct spatial organizations within the core-shell structures are highlighted. Following a detailed discussion of the specialized functions enabled by specific nanoparticles, the vision of the required fundamental insights and experimental studies for this class of microcarriers to fulfill its potential are sketched.

Progress of Drug Nanocrystal Self-Stabilized Pickering Emulsions: Construction, Characteristics In Vitro, and Fate In Vivo

A drug nanocrystal self-stabilized Pickering emulsion (DNSPE) is a novel Pickering emulsion with drug nanocrystals as the stabilizer. As a promising drug delivery system, DNSPEs have attracted increasing attention in recent years due to their high drug loading capacity and ability to reduce potential safety hazards posed by surfactants or specific solid particles. This paper comprehensively reviews the progress of research on DNSPEs, with an emphasis on the main factors influencing their construction, characteristics and measurement methods in vitro, and fate in vivo, and puts forward issues that need to be studied further. The review contributes to the advancement of DNSPE research and the promotion of their application in the field of drug delivery.

Antibacterial activity of a polysaccharide isolated from Artemisia argyi leaf against Staphylococcus aureus and mechanism investigation

Abuse of antibiotics has led to excessive amounts of antibiotic residues in food and environment, thus enhancing pathogenic bacterium resistance and threatening human health. Therefore, searching and developing safe and green antibiotic alternatives are necessary. In this study, an Artemisia argyi leaf polysaccharide (AALP) fraction was extracted and analyzed. Chemical composition analysis showed that the carbohydrate, uronic acid, protein, and polyphenol content in AALP were 68.3 % ± 4.13 %, 9.4 % ± 0.86 %, 1.79 % ± 0.27 %, and 0.16 % ± 0.035 %, respectively. Chromatographic results suggested that AALP contained rhamnose, arabinose, glucosamine, galactose, glucose, xylose, mannose, galacturonic acid, and glucuronic acid in a molar ratio of 9.26, 1.35, 1.18, 3.04, 48.51, 2.33, 31.26, 3.93, and 9.08; the weight average molecular weight, number average molecular weight, and polydispersity of AALP were 5.41 kDa, 4.63 kDa, and 1.168, respectively. Fourier transform infrared spectroscopy indicated that AALP constituted the polysaccharide-specific groups of CH, CO, and OH. Meanwhile, AALP showed a dose-dependent inhibitory effect on Staphylococcus aureus in the inhibition zone assay, and the minimal inhibitory concentration was 1.25 mg/mL. Furthermore, AALP disrupted the cell wall, depolarized the inner membrane potential, and inhibited the activities of succinate dehydrogenase and malate dehydrogenase in S. aureus.

Pickering Emulsions Based in Inorganic Solid Particles: From Product Development to Food Applications

Pickering emulsions (PEs) have attracted attention in different fields, such as food, pharmaceuticals and cosmetics, mainly due to their good physical stability. PEs are a promising strategy to develop functional products since the particles’ oil and water phases can act as carriers of active compounds, providing multiple combinations potentiating synergistic effects. Moreover, they can answer the sustainable and green chemistry issues arising from using conventional emulsifier-based systems. In this context, this review focuses on the applicability of safe inorganic solid particles as emulsion stabilisers, discussing the main stabilisation mechanisms of oil–water interfaces. In particular, it provides evidence for hydroxyapatite (HAp) particles as Pickering stabilisers, discussing the latest advances. The main technologies used to produce PEs are also presented. From an industrial perspective, an effort was made to list new productive technologies at the laboratory scale and discuss their feasibility for scale-up. Finally, the advantages and potential applications of PEs in the food industry are also described. Overall, this review gathers recent developments in the formulation, production and properties of food-grade PEs based on safe inorganic solid particles.

Protein-Based High Internal Phase Pickering Emulsions: A Review of Their Fabrication, Composition and Future Perspectives in the Food Industry

Protein-based high internal phase Pickering emulsions (HIPEs) are emulsions using protein particles as a stabilizer in which the volume fraction of the dispersed phase exceeds 74%. Stabilizers are irreversibly adsorbed at the interface of the oil phase and water phase to maintain the droplet structure. Protein-based HIPEs have shown great potential for a variety of fields, including foods, due to the wide range of materials, simple preparation, and good biocompatibility. This review introduces the preparation routes of protein-based HIPEs and summarizes and classifies the preparation methods of protein stabilizers according to their formation mechanism. Further outlined are the types and properties of protein stabilizers used in the present studies, the composition of the oil phase, the encapsulating substances, and the properties of the constituted protein-based HIPEs. Finally, future development of protein-based HIPEs was explored, such as the development of protein-based stabilizers, the improvement of emulsification technology, and the quality control of stabilizers and protein-based HIPEs.

Effects of essential oil extracted from Artemisia argyi leaf on lipid metabolism and gut microbiota in high-fat diet-fed mice

Artemisia argyi leaf is a well-known species in traditional Chinese medicine, and its essential oil (AAEO) has been identified to exert various physiological activities. The aim of this study was to investigate the effects of AAEO on lipid metabolism and the potential microbial role in high-fat diet (HFD)-fed mice. A total of 50 male mice were assigned to five groups for feeding with a control diet (Con), a high-fat diet (HFD), and the HFD plus the low (LEO), medium (MEO), and high (HEO) doses of AAEO. The results demonstrated that dietary HFD markedly increased the body weight gain compared with the control mice (p < 0.05), while mice in the HEO group showed a lower body weight compared to the HFD group (p < 0.05). The weight of fatty tissues and serum lipid indexes (TBA, HDL, and LDL levels) were increased in response to dietary HFD, while there was no significant difference in AAEO-treated mice (p < 0.05). The jejunal villus height was dramatically decreased in HFD-fed mice compared with the control mice, while HEO resulted in a dramatically higher villus height than that in the HFD group (p < 0.05). Microbial α-diversity was not changed in this study, but β-diversity indicated that microbial compositions differed in control, HFD, and EO subjects. At the genus level, the relative abundance of Bacteroides was greater (p < 0.05) in the feces of the Con group when compared to the HFD and EO groups. On the contrary, the abundance of Muribaculum was lower in the Con group compared to the HFD and EO groups (p < 0.05). Although the Muribaculum in the EO group was lower than that in the HFD group, there was no statistically notable difference between the HFD and EO groups (p > 0.05). Simultaneously, the relative abundance of Alistipes (p < 0.05) and Rikenella (p < 0.05) was also dramatically higher in the Con group than in the HFD and EO groups. The abundance of norank_f__norank_o__Clostridia_UCG-014 was lower in the HFD or EO group than in the Con group (p < 0.05). In conclusion, the results suggested that HEO could affect body weight and lipid metabolism without gut microbes in ICR mice, and it was beneficial for the structure of the jejunal epithelial tissue.

Full-Length Transcriptome Analysis Reveals Candidate Genes Involved in Terpenoid Biosynthesis in Artemisia argyi

Artemisia argyi is an important medicinal plant widely utilized for moxibustion heat therapy in China. The terpenoid biosynthesis process in A. argyi is speculated to play a key role in conferring its medicinal value. However, the molecular mechanism underlying terpenoid biosynthesis remains unclear, in part because the reference genome of A. argyi is unavailable. Moreover, the full-length transcriptome of A. argyi has not yet been sequenced. Therefore, in this study, de novo transcriptome sequencing of A. argyi's root, stem, and leaf tissues was performed to obtain those candidate genes related to terpenoid biosynthesis, by combining the PacBio single-molecule real-time (SMRT) and Illumina sequencing NGS platforms. And more than 55.4 Gb of sequencing data and 108,846 full-length reads (non-chimeric) were generated by the Illumina and PacBio platform, respectively. Then, 53,043 consensus isoforms were clustered and used to represent 36,820 non-redundant transcripts, of which 34,839 (94.62%) were annotated in public databases. In the comparison sets of leaves vs roots, and leaves vs stems, 13,850 (7,566 up-regulated, 6,284 down-regulated) and 9,502 (5,284 up-regulated, 4,218 down-regulated) differentially expressed transcripts (DETs) were obtained, respectively. Specifically, the expression profile and KEGG functional enrichment analysis of these DETs indicated that they were significantly enriched in the biosynthesis of amino acids, carotenoids, diterpenoids and flavonoids, as well as the metabolism processes of glycine, serine and threonine. Moreover, multiple genes encoding significant enzymes or transcription factors related to diterpenoid biosynthesis were highly expressed in the A. argyi leaves. Additionally, several transcription factor families, such as RLK-Pelle_LRR-L-1 and RLK-Pelle_DLSV, were also identified. In conclusion, this study offers a valuable resource for transcriptome information, and provides a functional genomic foundation for further research on molecular mechanisms underlying the medicinal use of A. argyi leaves.

Fabrication and antibacterial evaluation of peppermint oil-loaded composite microcapsules by chitosan-decorated silica nanoparticles stabilized Pickering emulsion templating

Novel peppermint oil (PO)-loaded composite microcapsules (CM) with hydroxypropyl methyl cellulose (HPMC)/chitosan/silica shells were effectively fabricated by PO Pickering emulsion, which were stabilized with chitosan-decorated silica nanoparticles (CSN). The surface modification of chitosan could improve the hydrophobicity of silica nanoparticles and favor their adsorption at the oil-water interface of PO Pickering emulsions. The microcapsule composite shells were formed dependent on the electrostatic adsorption of HPMC and CSN, and further subjected to spray-drying. The peppermint oil-loaded composite microcapsules with 100% HPMC as wall material (PO-CM@100%HPMC) seemed to be optimum formulation based on the prolonged release, acceptable entrapment efficiency (89.1%) and drug loading (25.5%). The PO-CM@100%HPMC could remarkably prolong the stability of PO. Moreover, the PO-CM@100%HPMC had a long-term antimicrobial activity (85.4%) against S. aureus and E. coli even after storage for 60 days. Therefore, the Pickering emulsions based microcapsules seemed to be a promising strategy for antibacterial application for PO.

Effect of cetyltrimethyl-ammonium bromide on the properties of hydroxyapatite nanoparticles stabilized Pickering emulsion and its cured poly(L-lactic acid) materials

Hydroxyapatite (HAp) nanoparticles stabilized Pickering emulsions were prepared by dichloromethane (CH₂ Cl₂ ) dissolved poly(L-lactic acid) (PLLA) as the oil phase and the deionized water with different concentrations of cetyltrimethyl-ammonium bromide (CTAB) as the aqueous phase. Effect of CTAB concentration on emulsions type and stability were studied. The emulsion type underwent a two-phase inversion, and emulsion stability increased first and then decreased with increasing CTAB concentrations. Besides, effect of CTAB concentration on zeta potential, aggregate size, contact angle of HAp nanoparticles and the oil-water interfacial tension were studied. The results indicated that zeta potential value of HAp nanoparticles changed from negative to positive, and the contact angle increased to over 80° initially and then decreased to below 40° rapidly. The distribution of HAp nanoparticles on the surface of emulsion droplets with different concentrations of CTAB (5 and 20 mM) was characterized using laser-induced confocal microscope. It revealed the distribution of HAp nanoparticles changed with different CTAB concentrations. The cured PLLA materials were obtained after the solvent being volatilized using as-received emulsions as templates. Scanning electron microscope images showed both microspheres and porous materials with interconnected pore structure were obtained. In conclusion, the microstructure of microspheres or porous PLLA materials is controllable by adjusting the property of HAp nanoparticles stabilized Pickering emulsions with appropriate amount of CTAB.

Dual Stimuli-Responsive Pickering Emulsions from Novel Magnetic Hydroxyapatite Nanoparticles and Their Characterization Using a Microfluidic Platform

Stimuli-responsive emulsifiers have emerged as a class of smart agents that can permit regulated stabilization and destabilization of emulsions, which is essential for food, cosmetic, pharmaceutical, and petroleum industries. Here, we report the synthesis of novel "smart" hydroxyapatite (HaP) magnetic nanoparticles and their corresponding stimuli-responsive Pickering emulsions and explore their movement under confined spaces using a microfluidic platform. Pickering emulsions prepared with our magnetic stearic acid-functionalized Fe₂O₃@HaP nanoparticles exhibited pronounced pH-responsive behavior. We observed that the diameter of emulsion droplets decreases with an increase in pH. Swift demulsification was achieved by lowering the pH, whereas the reformation of emulsions was achieved by increasing the pH; this emulsification-demulsification cycling was successful for at least ten cycles. We used a microfluidic platform to test the stability of the emulsions under flowing conditions and their response to a magnetic field. We observed that the emulsion stability was diminished and droplet coalescence was enhanced by the application of the magnetic field. The smart nanoparticles we developed and their HaP-based emulsions present promising materials for pharmaceutical and petroleum industries, where responsive emulsions with controlled stabilities are required.

Protocells self-assembled by hydroxyapatite nanoparticles: Highly efficient and selective enrichment of chlorophenols in an aqueous environment

In this paper, amphiphilic hydroxyapatite (HAP) nanoparticles were modified by dibutyl phosphate (DBP) via covalent bonding. The modified HAP particles (m-HAP) were employed as building blocks to construct oil-in-water (O/W) Pickering emulsion, that displayed an excellent performance on the enrichment of organic pollutants dissolved in wastewater by extracting the organic molecules into the oil phase. Environment-friendly organic solvent hexanol was selected as oil phase and three types of monochlorophenol (2-chlorophenol, 3-chlorophenol, 4-chlorophenol) were chosen as model pollutants in simulated wastewater. Two types of natural water were also tested as a proof of principle. The enrichment percentage of chlorophenols was up to 98% in 140 s, following first order kinetics. Thermodynamic study suggested that the enrichment process is spontaneous and exothermic. The external environment of the protocells, such as pH, ionic strength and the natural organic matter have been investigated. This study provides a novel, convenient and environment-friendly approach for enrichment and removal of trace organic pollutants in wastewater.

Long-term durability antibacterial microcapsules with plant-derived Chinese nutgall and their applications in wound dressing

Wound infection is a significant burden on public health. Most present antibacterial agents are typically toxic and devoid of long-term durability. We reported an antimicrobial microcapsule with Chinese nutgall (CN) encapsulated, which was a plant-derived extraction. It is biocompatible and has been used in traditional medicine systems. Sodium alginate (SA) and chitosan worked as shells. The promise of the design is to adopt biocompatible natural polymers and electrostatic attractive chitosan and SA form stable shells to keep long-term release of CN. The results exhibited microcapsules with integrated performance of biocompatibility, long-term durability (inhibition rate of 98.99% against S. aureus after 12 h and 100% after 12 h, 99.61% against E. coli after 6 h and 100% after 12 h), high antibacterial efficacy (with S. aureus inhibition zones of 7.67 mm and E. coli inhibition zones of 5.27 mm) and ease of storage (-20°C for more than 60 h). Their successful fabrication may provide new insights into application of traditional cotton gauze in a sustainable and multifunctional form.

Fabrication of cRGD-modified reduction-sensitive nanocapsule via Pickering emulsion route to facilitate tumor-targeted delivery

Purpose: To fabricate multifunctional nanocapsule via Pickering emulsion route to facilitate tumor-targeted delivery. Methods: Poly(N-isopropylacrylamide-co-acrylic acid) nanoparticles (PNA) stabilized nanocapsules were fabricated by Pickering emulsion (PE) technology. For controllable drug-release and enhancing targeted antitumor effects, the nanocapsules were crosslinked with cystamine and coupled on cell-surface molecule markers (cRGDfK) to achieve on-demand drug release and targeted delivery. Results: The fabricated PE and nanocapsules with average particle sizes (250 and 150 nm) were obtained. Encapsulation efficiency of hydrophobic anticancer drug (DOX) was determined as >90%. Release kinetic profiles for encapsulated nanocapsules displayed circulation stability and redox-sensitive releasing behavior with the supposed increase bioavailability. Both cytotoxicity assay, cellular uptake analysis and anticancer efficacy in B16F10 murine model demonstrated these redox-responsive drug-release and active targeted delivery. Conclusion: The results clearly demonstrated nanocapsule via PE route as promising candidate to provide an effective platform for incorporating hydrophobic drug for targeted cancer chemotherapy.

Chemical Composition and Antimicrobial Activities of Artemisia argyi Lévl. et Vant Essential Oils Extracted by Simultaneous Distillation-Extraction, Subcritical Extraction and Hydrodistillation

Artemisia argyi Lévl. et Vant essential oil could be used as a good antimicrobial flavouring agent and applied in the food industry. In this study, three methods, including simultaneous distillation-extraction (SDE), subcritical extraction and hydrodistillation, were applied to extract A. argyi essential oil. Compared with subcritical extraction (1%) and hydrodistillation (0.5%), SDE gave a higher yield (1.2%). Components of the essential oils were analysed with gas chromatography-mass spectrometry (GC-MS), and the most abundant ingredients were caryophyllene oxide, neointermedeol, borneol, α-thujone and β-caryophyllene. These five components accounted for 82.93%, 40.90% and 40.33% for SDE, subcritical extraction, and hydrodistillation, respectively. Based on agar disc diffusion and minimum inhibitory concentration (MIC) assays, SDE oil showed a significant inhibitory effect towards Listeria monocytogenes, Escherichia coli, Proteus vulgaris, Salmonella enteritidis and Aspergillus niger. Furthermore, electron microscope observations (SEM) confirmed that SDE oil could obviously deform cell morphology and destroy the structure of cell walls. Performances showed that SDE was a promising process for extracting A. argyi essential oil with both high yield and antimicrobial activity.

De novo assembly and analysis of the Artemisia argyi transcriptome and identification of genes involved in terpenoid biosynthesis

Artemisia argyi Lev. et Vant. (A. argyi) is widely utilized for moxibustion in Chinese medicine, and the mechanism underlying terpenoid biosynthesis in its leaves is suggested to play an important role in its medicinal use. However, the A. argyi transcriptome has not been sequenced. Herein, we performed RNA sequencing for A. argyi leaf, root and stem tissues to identify as many as possible of the transcribed genes. In total, 99,807 unigenes were assembled by analysing the expression profiles generated from the three tissue types, and 67,446 of those unigenes were annotated in public databases. We further performed differential gene expression analysis to compare leaf tissue with the other two tissue types and identified numerous genes that were specifically expressed or up-regulated in leaf tissue. Specifically, we identified multiple genes encoding significant enzymes or transcription factors related to terpenoid synthesis. This study serves as a valuable resource for transcriptome information, as many transcribed genes related to terpenoid biosynthesis were identified in the A. argyi transcriptome, providing a functional genomic basis for additional studies on molecular mechanisms underlying the medicinal use of A. argyi.

Determination of Eupatilin in Folium artemisiae Argyi and Its Inhibitory Effect on Hepatoma Cells

Aim

The aim of this study is to establish a method for determination of eupatilin in Folium artemisiae Argyi and observe the inhibitory effect of Folium artemisiae Argyi extract on human hepatoma SMMC-7721 cells.

Methods

High-performance liquid chromatograph system with 2910 pump, 2930 UV detector, and N2000 workstation was used for determination of eupatilin in Folium artemisiae Argyi. Human hepatoma SMMC-7721 cells were cultured and cell proliferation was measured using the MTT assay. The expression protein levels of p53, Topo II, and bcl-2 were detected using Western blotting.

Results

Eupatilin exhibited a linearity range of 0.5-3.0 μg/mL and a recovery of 100.72%, relevant standard derivation = 2.28%. Folium artemisiae Argyi extract had marked cytostatic and cytotoxic effects on SMMC-7721 cells, inhibited the SMMC-7721 colony formation in a dose-dependent manner. Folium artemisiae Argyi extract already possessed delayed effect after treating SMMC-7721 cells for 8 h, which became obvious at 12 h from treatment. After drug withdrawal, cells still tended to apoptosis. Folium artemisiae Argyi extract could inhibit p53, Topo II, and bcl-2 expressions in tumor cells. The present method for determination of eupatilin is simple, fast, accurate, sensitive, and reproducible.

Conclusion

Hepatoma SMMC-7721 cells are quite sensitive to Folium artemisiae Argyi extract, which may be associated with its suppression of p53, Topo II, and bcl-2 expressions.

SUMMARY

The study aimed to establish a method for determination of eupatilin in Folium artemisiae Argyi and observe the inhibitory effect of Folium artemisiae Argyi extract on human hepatoma SMMC-7721 cells. The results suggested that the present method for determination of eupatilin is simple, fast, accurate, sensitive, and reproducible. Hepatoma SMMC-7721 cells are quite sensitive to Folium artemisiae Argyi extract, which may be associated with its suppression of p53, Topo II, and bcl-2 expressions. Abbreviations used: HPLC: High-performance liquid chromatograph; OD: Optical density; RSD: Relevant standard derivation; IC₅₀: Inhibitory 50% concentration.

Engineered Fe(OH)3 nanoparticle-coated and rhBMP-2-releasing PLGA microsphere scaffolds for promoting bone regeneration by facilitating cell homing and osteogenic differentiation

Iron facilitates cell homing and enhances the capacity of rhBMP-2.

An Overview of Pickering Emulsions: Solid-Particle Materials, Classification, Morphology, and Applications

Pickering emulsion, a kind of emulsion stabilized only by solid particles locating at oil-water interface, has been discovered a century ago, while being extensively studied in recent decades. Substituting solid particles for traditional surfactants, Pickering emulsions are more stable against coalescence and can obtain many useful properties. Besides, they are more biocompatible when solid particles employed are relatively safe in vivo. Pickering emulsions can be applied in a wide range of fields, such as biomedicine, food, fine chemical synthesis, cosmetics, and so on, by properly tuning types and properties of solid emulsifiers. In this article, we give an overview of Pickering emulsions, focusing on some kinds of solid particles commonly serving as emulsifiers, three main types of products from Pickering emulsions, morphology of solid particles and as-prepared materials, as well as applications in different fields.

Anti-inflammatory and blood stasis activities of essential oil extracted from Artemisia argyi leaf in animals

Artemisia argyi leaf is a well-known species in traditional Chinese medicine. However, the anti-inflammatory and activating blood stasis activities of its essential oil (AAEO) have not been explored in vivo. The present study measured the contents of three chemical components by gas chromatography (GC). The anti-acute inflammatory effects of AAEO were investigated in dimethyl benzene, glacial acetic acid and carrageenan-induced animals through skin administration or by oral gavage, respectively. The effects of AAEO on haemorheology were studied in a rat acute blood stasis model. The contents of eucalyptol, camphor and borneol in AAEO were 254.4, 51.6 and 58.7 mg/g, respectively. All dosages of AAEO by skin administration significantly decreased the swelling in dimethyl benzene-induced ear oedema and carrageenan-induced paw oedema, and reduced the permeability in glacial acetic acid-induced abdominal blood capillary (p < 0.01). Meanwhile, haemorheology indexes such as whole blood viscosity and the erythrocyte aggregation index significantly decreased only in the high dosage group. In addition, the effects of AAEO by oral gavage were weaker than skin administration at the medium dose in the experiments. It suggests that AAEO has better absorption bioavailability and pharmacological effects through skin administration due to the better skin permeability of essential oil than gastrointestinal absorption.

Facile fabrication of tea tree oil-loaded antibacterial microcapsules by complex coacervation of sodium alginate/quaternary ammonium salt of chitosan

In this study, flavoured tea tree oil (TTO)-loaded antibacterial microcapsules were developed based on the complex coacervation of sodium alginate (SA) and a quaternary ammonium salt of chitosan (HACC).

Facile preparation of biphasic-induced magnetic icariin-loaded composite microcapsules by automated in situ click technology

This research aims to prepare the biphasic-induced magnetic composite microcapsules (BIMCM) as a promising environmental stimuli-responsive delivery vehicle to dispose the problem of drug burst effect. The paper presented a novel automated in situ click technology of magnetic chitosan/nano hydroxyapatite (CS/nHA) microcapsules. Fe3O4 magnetic nanoparticles (MNP) and nHA were simultaneously in situ crystallized by one-step process. Icariin (ICA), a plant-derived flavonol glycoside, was combined to study drug release properties of BIMCM. BIMCM were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and Thermal gravimetric analysis/Differential Scanning Calorimetry(TGA/DSC) in order to reveal their component and surface morphology as well as the role of the in situ generated Fe3O4 MNP and nHA. The magnetic test showed the BIMCM were super-paramagnetic. Both in situ generated Fe3O4 MNP and nHA serve as stable inorganic crosslinkers in BIMCM to form many intermolecular crosslinkages for the movability of the CS chains. This makes ICA loaded microcapsules take on a sustained release behavior and results in the self-adjusting of surface morphology, decreasing of swelling and degradation rates. In addition, in vitro tests were systematically carried out to examine the biocompatibility of the microcapsules by MTT test, Wright-Giemsa dying assay and AO/EB fluorescent staining method. These results demonstrated that successful introduction of the in situ click Fe3O4 MNP provided an alternative strategy because of magnetic sensitivity and sustained release. As such, the novel ICA loaded biphasic-induced magnetic CS/nHA/MNP microcapsules are expected to find potential applications in drug delivery system for bone repair.

Pickering high internal phase emulsion-based hydroxyapatite-poly(ε-caprolactone) nanocomposite scaffolds

Biocompatible, biodegradable and bioactive nanocomposite (NC) scaffolds with well-defined interconnected porous structures have attracted increasing attention in bone tissue engineering. In this work, we develop a facile method to fabricate poly(l-lactic acid)-modified hydroxyapatite (g-HAp)-poly(ε-caprolactone) (PCL) NC porous scaffolds by solvent evaporation based on water-in-dichloromethane (W/O) Pickering high internal phase emulsion (HIPE) templates, which are stabilized using g-HAp nanoparticles. The resultant porous scaffolds demonstrate interconnected and rough pore structures, which can be adjusted readily by varying g-HAp nanoparticle concentration, PCL concentration and the internal phase volume fraction. Moreover, the investigation of mechanical properties and in vitro biomineralization activity shows that the Young's modulus, compressive stress and bioactivity of the fabricated porous scaffolds are significantly enhanced upon increasing the g-HAp nanoparticle concentration. In addition, in vitro drug release studies of the porous scaffolds using ibuprofen (IBU) as a model drug show that the loaded IBU displays a sustained release profile. In vitro cell culture assays confirm that mouse bone mesenchymal stem cells can adhere, spread, and proliferate on the porous scaffolds, indicating that the porous scaffolds are biocompatible. All these results suggest that the fabricated g-HAp-PCL NC scaffolds have a promising potential for bone tissue engineering application.

Preparation and characterization of alginate–N-2-hydroxypropyl trimethyl ammonium chloride chitosan microcapsules loaded with patchouli oil

In this work, alginate (Alg)–N-2-hydroxypropyl trimethyl ammonium chloride chitosan (HACC) microcapsules containing patchouli oil were prepared by a complex coacervation method.

Facile fabrication of poly(L-lactic acid)-grafted hydroxyapatite/poly(lactic-co-glycolic acid) scaffolds by Pickering high internal phase emulsion templates

Porous scaffolds consisting of bioactive inorganic nanoparticles and biodegradable polymers have gained much interest in bone tissue engineering. We report here a facile approach to fabricating poly(l-lactic acid)-grafted hydroxyapatite (g-HAp)/poly(lactide-co-glycolide) (PLGA) nanocomposite (NC) porous scaffolds by solvent evaporation of Pickering high internal phase emulsion (HIPE) templates, where g-HAp nanoparticles act as particulate stabilizers. The resultant porous scaffolds exhibit an open and rough pore structure. The pore structure and mechanical properties of the scaffolds can be tuned readily by varying the g-HAp nanoparticle concentration and internal phase volume fraction of the emulsion templates. With increasing the g-HAp concentration or decreasing the internal phase volume fraction, the pore size and the porosity decrease, while the Young's modulus and the compressive stress enhance. Moreover, the in vitro mineralization tests show that the bioactivity of the scaffolds increases with increasing the g-HAp concentration. Furthermore, the anti-inflammatory drug ibuprofen (IBU) is loaded into the scaffolds, and the drug release studies indicate that the loaded-IBU exhibits a sustained release profile. Finally, in vitro cell culture assays prove that the scaffolds are biocompatible because of supporting adhesion, spreading, and proliferation of mouse bone mesenchymal stem cells. All the results indicate that the solvent evaporation based on Pickering HIPE templates is a promising alternative method to fabricate NC porous scaffolds for potential bone tissue engineering applications.

Mineralization and drug release of hydroxyapatite/poly(l-lactic acid) nanocomposite scaffolds prepared by Pickering emulsion templating

Biodegradable and bioactive nanocomposite (NC) biomaterials with controlled microstructures and able to deliver special drugs have gained increasing attention in bone tissue engineering. In this study, the hydroxyapatite (HAp)/poly(l-lactic acid) (PLLA) NC scaffolds were facilely prepared using solvent evaporation from templating Pickering emulsions stabilized with PLLA-modified HAp (g-HAp) nanoparticles. Then, in vitro mineralization experiments were performed in a simulated body fluid (SBF) to evaluate the bioactivity of the NC scaffolds. Moreover, in vitro drug release of the NC scaffolds using anti-inflammatory drug (ibuprofen, IBU) as the model drug was also investigated. The results showed that the NC scaffolds possessed interconnected pore structures, which could be modulated by varying the g-HAp nanoparticle concentration. The NC scaffolds exhibited excellent bioactivity, since they induced the formation of calcium-sufficient, carbonated apatite nanoparticles on the scaffolds after mineralization in SBF for 3 days. The IBU loaded in the NC scaffolds showed a sustained release profile, and the release kinetic followed the Higuchi model with diffusion process. Thus, solvent evaporation based on Pickering emulsion droplets is a simple and effective method to prepare biodegradable and bioactive porous NC scaffolds for bone repair and replacement applications.

Macroporous antibacterial hydrogels with tunable pore structures fabricated by using Pickering high internal phase emulsions as templates

Pickering-based antibacterial hydrogels with tunable pore structures were fabricated by using high internal phase emulsion templates.