Apatinib and gamabufotalin co-loaded lipid/Prussian blue nanoparticles for synergistic therapy to gastric cancer with metastasis

Due to the non-targeted release and low solubility of anti-gastric cancer agent,apatinib(Apa),a first-line drug with long-term usage in a high dosage often induces multi-drug resistance and causes serious side effects.In order to avoid these drawbacks,lipid-film-coated Prussian blue nanoparticles(PB NPs)with hyaluronan(HA)modification was used for Apa loading to improve its solubility and targeting ability.Furthermore,anti-tumor compound of gamabufotalin(CS-6)was selected as a partner of Apawith reducing dosage for combinational gastric therapy.Thus,HA-Apa-Lip@PB-CS-6 NPs were constructed to synchronously transport the two drugs into tumor tissue.In vitro assay indicated that HA-Apa-Lip@PB-CS-6 NPs can synergistically inhibit proliferation and invasion/metastasis of BGC-823 cells via downregulating vascular endothelial growth factor receptor(VEGFR)and matrix metalloproteinase-9(MMP-9).In vivo assay demonstrated strongest anti-tumor growth and liver metastasis of HA-Apa-Lip@PB-CS-6 NPs administration in BGC-823 cells-bearing mice compared with other groups due to the excellent penetration in tumor tissues and outstanding synergistic effects.In summary,we have successfully developed a new nanocomplexes for synchronous Apa/CS-6 delivery and synergistic gastric cancer(GC)therapy.

Functionalized lipid nanoparticles modulate the blood-brain barrier and eliminate α-synuclein to repair dopamine neurons

The challenge in the clinical treatment of Parkinson's disease lies in the lack of disease-modifying therapies that can halt or slow down the progression. Peptide drugs, such as exenatide (Exe), with potential disease-modifying efficacy, have difficulty in crossing the blood-brain barrier (BBB) due to their large molecular weight. Herein, we fabricate multi-functionalized lipid nanoparticles (LNP) Lpc-BoSA/CSO with BBB targeting, permeability-increasing and responsive release functions. Borneol is chemically bonded with stearic acid and, as one of the components of Lpc-BoSA/CSO, is used to increase BBB permeability. Immunofluorescence results of brain tissue of 15-month-old C57BL/6 mice show that Lpc-BoSA/CSO disperses across the BBB into brain parenchyma, and the amount is 4.21 times greater than that of conventional LNP. Motor symptoms of mice in Lpc-BoSA/CSO-Exe group are significantly improved, and the content of dopamine is 1.85 times (substantia nigra compacta) and 1.49 times (striatum) that of PD mice. α-Synuclein expression and Lewy bodies deposition are reduced to 51.85% and 44.72% of PD mice, respectively. Immunohistochemical mechanism studies show AKT expression in Lpc-BoSA/CSO-Exe is 4.23 times that of PD mice and GSK-3β expression is reduced to 18.41%. Lpc-BoSA/CSO-Exe could reduce the production of α-synuclein and Lewy bodies through AKT/GSK-3β pathway, and effectively prevent the progressive deterioration of Parkinson's disease. In summary, Lpc-BoSA/CSO-Exe increases the entry of exenatide into brain and promotes its clinical application for Parkinson's disease therapy.

Acyclovir-Loaded Solid Lipid Nanoparticles: A Permeation and Penetrability Study

Herpes simplex virus type I is a cutaneous infection treated with acyclovir. The topical treatment has therapeutic challenges due to the deficient delivery of the drug through epithelial barriers. This results in an inadequate drug-virus interaction in the basal epidermis (virus replication site). For this reason, it is essential to generate drug carrier systems that overcome these limitations. In this study, we evaluated the permeation (through in vitro test Franz cells) and penetration (by ex vivo test Tape Stripping) of a topical formulation of acyclovir loaded in solid lipid nanoparticles and a conventional formulation (Aciclor®). The acyclovir solid lipid nanoparticles were prepared using hot homogenization and sonication methods. The results yielded a particle size of 85 ± 2 nm, a polydispersity index of 0.24 ± 0.01, a zeta potential of −16 ± 2 mV, and 94% ± 3% of encapsulated drug. The in vitro test revealed that the permeability of acyclovir solid lipid nanoparticles formulation was superior compared to reference formulation, with values of 1473.74 ± 30.14 µg/cm2 for the solid lipid nanoparticles and 893.36 ± 38.09 µg/cm2 for the reference formulation. The ex vivo test demonstrated that acyclovir solid lipid nanoparticles exhibited superior penetrability through the stratum corneum compared to the reference formulation, with total amounts of 3767 µg for the solid lipid nanoparticles and 2162 µg for the reference formulation. These findings seem promising in advancing new effective therapies against herpes generated by herpes simplex virus type I.

Characteristics and Transdermal Drug Delivery of Triamcinolone-Acetonide-Acetate-Loaded Solid Lipid Nanoparticles Carbomer Gel

Aim To prepare triamcinolone-acetonide-acetate (TAA)-loaded solid lipidnanoparticles (SLN) carbomer gel with tripalmitin glyceride (TPG), and investigate theircharacteristics and transdermal drug delivery. Methods SLN suspension was prepared by high-pressurehomogenization technique, and then mixed with carbomer gel matrix to get SLN gel. The morphology,particle size with polydispersi-ty index (PI) and zeta potential were examined by atomic forcemicroscopy (AFM) and photon correlation spectroscopy (PCS). The entrapment efficiency, stability andin vitro drug release were also studied. The transdermal drug delivery through porcine ear skin wasevaluated using modified Franz diffusion cells. Results The SLN had a spherical shape with theaverage size of (95.5 - 186.2) nm, the zeta potential of (-26.3- -15.7) mV and the entrapmentefficiency of 67.4%-90.3% for different TAA encapsulated compounds. TAA-SLN carbomer gel had goodstability, the release profile in vitro fitted Higuchi equation. In comparison with conventionalhydrogels, TAA-SLN carbomer gel resulted in higher drug permeation amount and drug deposition withinporcine ear skin after 24 h penetration experiment. Conclusion TAA-SLN carbomer gel is preparedwith stable physicochemical properties. The release profile and improved drug permeation into skinmake it be a promising vehicle for transdermal drug delivery.

Development of composite PLGA microspheres containing exenatide-encapsulated lecithin nanoparticles for sustained drug release

This study aimed to prepare poly(D, L-lactic-co-glycolic acid) microspheres(PLGA-Ms)by a modified solid-in-oil-in-water(S/O/W) multi-emulsion technique in order to achieve sustained release with reduced initial burst and maintain efficient drug concentration for a prolonged period of time. Composite PLGA microspheres containing exenatideencapsulated lecithin nanoparticles(Ex-NPs-PLGA-Ms) were obtained by initial fabrication of exenatide-loaded lecithin nanoparticles(Ex-NPs) via the alcohol injection method,followed by encapsulation of Ex-NPs into PLGA microspheres. Compared to Ms prepared by the conventional water-in-oil-in-water(W/O/W) technique(Ex-PLGA-Ms), Ex-NPs-PLGAMs showed a more uniform particle size distribution, reduced initial burst release, and sustained release for over 60 d in vitro. Cytotoxicity studies showed that Ms prepared by both techniques had superior biocompatibility without causing any detectable cytotoxicity.In pharmacokinetic studies, the effective drug concentration was maintained for over 30 d following a single subcutaneous injection of two types of Ms formulation in rats, potentially prolonging the therapeutic action of Ex. In addition, administration of Ex-NPs-PLGA-Ms resulted in a more smooth plasma concentration-time profile with a higher area under the curve(AUC) compared to that of Ex-PLGA-Ms. Overall, Ex-NPs-PLGA-Ms prepared by the novel S/O/W method could be a promising sustained drug release system with reduced initial burst release and prolonged therapeutic efficacy.

Targeting the resolution pathway of inflammation using Ac2–26 peptide-loaded PEGylated lipid nanoparticles for the remission of rheumatoid arthritis

Rheumatoid arthritis(RA)is a common autoimmune disease characterized by joint inflammation and immune dysfunction.Although various therapeutic approaches have been utilized for the treatment of RA in clinical applications,the low responsiveness of RA patients and undesired systemic toxicity are still unresolved problems.Targeting the resolution pathway of inflammation with pro-resolving mediators would evoke the protective actions of patient for combating the inflammation.Ac2–26,a 25-amino acid peptide derived from Annexin A(a pro-resolving mediator),has shown good efficacy in the treatment of inflammatory disorders.However,the low bioavailability of Ac2–26 peptides hinders their efficacy in vivo.In this paper,we formed PEGylated lipid nanoparticles(LDNPs)by the co-assembly of l-ascorbyl palmitate(L-AP)and N-(carbonyl methoxypolyethylene glycol-2000)-1,2-distearoyl-sn–glycero-3-phosphoethanolamine(DSPE-PEG 2 k)to encapsulate and deliver Ac2–26 peptides to the arthritic rats.They showed good stability and biocompatibility.After being intravenously administrated,Ac2–26 peptide-loaded PEGylated lipid nanoparticles(ADNPs)showed the prolonged in vivo circulation time and enhanced accumulation in inflamed sites.In vivo therapeutic evaluations revealed that ADNPs could attenuate synovial inflammation and improve joint pathology.Therefore,the pro-resolving therapeutic strategy using ADNPs is effective in RA treatment.

Relaxin-encapsulated polymeric metformin nanoparticles remodel tumor immune microenvironment by reducing CAFs for efficient triple-negative breast cancer immunotherapy

Cancer-associated fibroblasts(CAFs)are one of the most abundant stromal cells in the tumor microenvironment which mediate desmoplastic response and are the primary driver for an immunosuppressive microenvironment,leading to the failure of triple-negative breast cancer(TNBC)immunotherapy.Therefore,depleting CAFs may enhance the effect of immunotherapy(such as PD-L1 antibody).Relaxin(RLN)has been demonstrated to significantly improve transforming growth factor-β(TGF-β)induced CAFs activation and tumor immunosuppressive microenvironment.However,the short half-life and systemic vasodilation of RLN limit its in vivo efficacy.Here,plasmid encoding relaxin(pRLN)to locally express RLN was delivered with a new positively charged polymer named polymeric metformin(PolyMet),which could increase gene transfer efficiency significantly and have low toxicity that have been certified by our lab before.In order to improve the stability of pRLN in vivo,this complex was further formed lipid poly-γ-glutamic acid(PGA)/PolyMetpRLN nanoparticle(LPPR).The particle size of LPPR was 205.5±2.9 nm,and the zeta potential was+55.4±1.6 mV.LPPR displayed excellent tumor penetrating efficacy and weaken proliferation of CAFs in 4T1luc/CAFs tumor spheres in vitro.In vivo,it could reverse aberrantly activated CAFs by decreasing the expression of profibrogenic cytokine and remove the physical barrier to reshape the tumor stromal microenvironment,which enabled a 2.2-fold increase in cytotoxic T cell infiltration within the tumor and a decrease in immunosuppressive cells infiltration.Thus,LPPR was observed retarded tumor growth by itself in the 4T1 tumor bearing-mouse,and the reshaped immune microenvironment further led to facilitate antitumor effect when it combined with PD-L1 antibody(aPD-L1).Altogether,this study presented a novel therapeutic approach against tumor stroma using LPPR to achieve a combination regimen with immune checkpoint blockade therapy against the desmoplastic TNBC model.

Bimodal visualization of colorectal uptake of nanoparticles in dimethylhydrazine-treated mice

AIM:To investigate colorectal uptake of solid lipid nanoparticles(SLNs) in mice receiving different doses of 1,2-dimethylhydrazine(DMH) using magnetic resonance(MR) and laser-scanning confocal fluorescence microscope(LSCFM) imaging.METHODS:Eight mice were sacrificed in a pilot study to establish the experimental protocol and to visualize colorectal uptake of SLNs in normal mice.Gadopentetate dimeglumine and fluorescein isothiocyanate(FITC)-loaded SLN(Gd-FITC-SLN) enemas were performed on mice receiving DMH for 10 wk(group 1,n = 9) or 16 wk(group 2,n = 7) and FITC-SLN enema wasperformed on 4 DMH-treated mice(group 3).Pre-and post-enema MR examinations were made to visualize the air-inflated distal colorectum.Histological and LSCFM examinations were performed to verify colorectal malignancy and to track the distribution of SLNs.RESULTS:Homogeneous enhancement and dense fluorescence(FITC) deposition in colorectal wall were observed in normal mice and 1 DMH-treated mouse(group 1) on fluid attenuated inversion recovery(FLAIR) and LSCFM images,respectively.Heterogeneous mural enhancement was found in 6 mice(4 in group 1;2 in group 2).No visible mural enhancement was observed in the other mice.LSCFM imaging revealed linear fluorescence deposition along the colorectal mucosa in all groups.Nine intraluminal masses and one prolapsed mass were detected by MR imaging with different enhancement modes and pathologies.Interstitial FITC deposition was identified where obvious enhancement was observed in FLAIR images.Bladder imaging agent accumulations were observed in 11 of 16 DMH-treated mice of groups 1 and 2.CONCLUSION:There are significant differences in colorectal uptake and distribution of SLNs between normal and DMH-treated mice,which may provide a new mechanism of contrast for MR colonography.

New research on development of solid lipid nanoparticles

To review the latest research development of the solid lipid nanoparticles(SLN) according to the recent relevant literatures.Each preparations of the SLN have advantages and disadvantages.Among the total preparations of the SLN.the high pressure homogenization(HPH) and the microemulsion tech- nique are to praise highly.The drug incorporation and release profiles could be modified as adjustment of production parameters.The SLNis an excellent drug delivery system and has broad prospects in the phar- maceutical field.

Efficacy of combined albendazol and praziquntel and their loaded solid lipid nanoparticles components in chemoprophylaxis of experimental hydatidosis

Objective:To evaluate the efficacy of combined ABZ and PZQ and their solid lipid nanoparticles in chemoprophylaxis of cystic echinococcosis(CE).Methods:ABZ and PZQ loaded solid lipid nanoparticles(SLNs) were prepared by high shear homogenization and microemulsion congealing techniques with some minor modification.Nanoparticles average size,polydispersity index(PDI),and particle size distribution were determined by scanning electron microscopy(SEM) and photon correlation spectroscopy.Forty females BALB/c were experimentally infected by protoscoleces(PSC) and randomly divided into four equal groups of 10 mice.After the end of the 3 months treatment period and 2 months rest,mice were sacrificed and the peritoneal cavity was opened for removal,counting,measuring,and histological analysis of hydatid cyst.Results:The results indicated that ABZ and PZQ chemoprophylaxis treatment reduced the wet weight and size of developed cysts 77.3% and 79%,respectively.The corresponding result for the ABZ and PZQ loaded SLNs was 83% and 85%,respectively.Conclusions:This study for the first time demonstrated that ABZ and PZQ loaded SLNs is superior to free ABZ and PZQ for the chemoprophylaxis of CE in mice.

Synthetic and nature-derived lipid nanoparticles for neural regeneration

Challenges and opportunities in nerve regeneration： The central nervous system （CNS） has a limited ability to regen- erate. Subsequent to spinal injury, glial scar formation, creat- ed by fibroblasts, neuroglia, monocytes, and endothelial cells, inhibits regeneration of the injured nerve. The peripheral nervous system （PNS） has a greater regeneration potential than the CNS; however, the current gold standard of treat- ment for a large nerve defect is still autologous nerve grafts, which require multiple surgeries. For this reason, researchers have been trying to regenerate nervous tissues, including brain, spinal cord. and PeriPheral nerves, for decades.

Monitoring the in vivo siRNA release from lipid nanoparticles based on the fluorescence resonance energy transfer principle

The siRNA-loaded lipid nanoparticles have attracted much attention due to its significant gene silencing effect and successful marketization.However,the in vivo distribution and release of siRNA still cannot be effectively monitored.In this study,based on the fluorescence resonance energy transfer(FRET)principle,a fluorescence dye Cy5-modified survivin siRNA was conjugated to nanogolds(Au-DR-siRNA),which were then wrapped with lipid nanoparticles(LNPs)for monitoring the release behaviour of siRNA in vivo.The results showed that once Au-DR-siRNA was released from the LNPs and cleaved by the Dicer enzyme to produce free siRNA in cells,the fluorescence of Cy5 would change from quenched state to activated state,showing the location and time of siRNA release.Besides,the LNPs showed a significant antitumor effect by silencing the survivin gene and a CT imaging function superior to iohexol by nanogolds.Therefore,this work provided not only an effective method for monitoring the pharmacokinetic behaviour of LNP-based siRNA,but also a siRNA delivery system for treating and diagnosing tumors.

Preparation, optimization, and characterization of chitosancoated solid lipid nanoparticles for ocular drug delivery

The present study aimed to develop and optimize chitosan coated solid lipid nanoparticles(chitosan-SLNs)encapsulated with methazolamide. Chitosan-SLNs were successfully prepared by a modified oil-in-water emulsification-solvent evaporation method with glyceryl monostearate as the solid lipid and phospholipid as the surfactant. Systematic screening of formulation factors was carried out. The optimized formula for preparation was screened by orthogonal design as well as Box-Behnken design with entrapment efficiency, particle size and zeta potential as the indexes. The entrapment efficiency of the optimized formulation(methazolamide-chitosan-SLNs)prepared was(58.5± 4.5)%,Particle size(247.7 ± 17.3) nm and zeta potential(33.5 ±3.9) mV. Transmission electron microscopy showed homogeneous spherical particles in the nanometer range. A prolonged methazolamide in vitro release profile was obtained in the optimized chitosan-SLNs suspension compared with methazolamide solution. No ocular damages were observed in the susceptibility test on albino rabbits. The results suggest that the combination of orthogonal design and Box-Behnken design is efficient and reliable in the optimization of nanocarriers, and chitosanSLNs is a potential carrier for ophthalmic administration.

Solid lipid nanoparticles loading adefovir dipivoxil for antiviral therapy

Herein,solid lipid nanoparticles(SLN)were proposed as a new drug delivery system for adefovir dipivoxil(ADV). The octadecylamine-fluorescein isothiocynate(ODA-FITC)was synthesized and used as a fluorescence maker to be incorporated into SLN to investigate the time-dependent cellular uptake of SLN by HepG2.2.15.The SLN of monostearin with ODA-FITC or ADV were prepared by solvent diffusion method in an aqueous system.About 15 wt%drug entrapment efficiency(EE)and 3 wt% drug loading(DL)could be reached in SLN loading ADV.Comparing with free ADV,the inhibitory effects of ADV loaded in SLN on hepatitis B surface antigen(HBsAg),hepatitis B e antigen(HBeAg)and hepatitis B virus(HBV)DNA levels in vitro were significantly enhanced.

Storage Stability of Alpha-Lipoic Acid-loaded Lipid Nanoparticles

Alpha-lipoic acid-loaded lipid nanoparticles(ALA-LNs) were prepared by high pressure homogenization method.The influences of storage conditions such as time and temperature on the physical and chemical storage stability of ALA-LNs were studied in details.The stability was evaluated by particle size and polydispersity index,morphology of ALA-LNs,and capacity of ALA loading.The dilution and pH stability of ALA-LNs suspensions were also studied.After three months storage,the mean size of ALA-LNs at 4 and 40 ℃ was increased by 2.68% and 3.62% compared with the original size,respectively.ALA-LNs stored at 40 ℃ had ellipsoid shape and the mean size was about 152 nm(SD=23.6).The loading capacity of ALA at 40 ℃ was much higher than those stored at other two temperatures.The good dilution and pH stability were also demonstrated.The sample had good fluidity even at 4 ℃.

Bovine Serum Albumin Loaded Solid Lipid Nanoparticles Prepared by Double Emulsion Method

Solid lipid nanoparticles loaded with bovine serum albumin（BSA） were prepared by a double emulsion method. As the mass fraction of the model drug BSA increased from 0 to 15%, the particle size gradually increased. The physical stability of the nanoparticles was investigated by zeta potential measurement and they were shown to be quite stable. Fluorescence spectroscopy confirmed that the loaded position of BSA was on the interface between the inner aqueous phase and the solid lipid phase. Both Fourier-transform infrared spectroscopy and circular dichroism spectra indicate that BSA in the nanoparticles was not destroyed, but the secondary structure was disrupted slightly.

Evaluation of atherosclerotic lesions in cholesterol-fed mice during treatment with paclitaxel in lipid nanoparticles： a magnetic resonance imaging study

Cholesterol-core nanoparticles （LDE） have been shown to be recognized by low-density lipoprotein receptors （LDLR） after administration; therefore, LDE is an ideal vehicle to deliver drug with targeting property. Paclitaxel, when incorporated into LDE, promotes atherosclerosis regression with reduced drug toxicity in rabbits through LDLR. Here, we tested whether LDE-paclitaxel could still be effective in reducing diet-induced atherosclerosis in a mouse model without LDLR. Nineteen LDLR knockout male mice were fed 1% cholesterol for 12 weeks. Then, 12 animals received 4-weekly intraperitoneal LDE-paclitaxel （4 mg/kg） while 7 controls received saline solution. On week 12 and 16, in vivo MR/of the aortic roots was performed. Aorta macroscopy was made after euthanasia. Reduction ofatherosclerotic lesions was observed. LDE-paclitaxel treatment resulted in reduction of wall area （14%） and stenosis （22%） by MR/and 33% by macroscopy. Thus, LDE-paclitaxel may produce pharmacological effects through LDE uptake by mechanisms other than LDLR.

Multi-methodological Approach to Evaluate Performances of Mucoadhesive Oral Gel Based on Nanoparticles

Oral mucositis due to chemotherapy and irradiation continues to be an important clinical problem. The effectiveness of hyaluronic acid-based compounds in accelerated healing and helping manage pain in patients with oral mucositis was demonstrated. It was investigated a protective and regenerative effect of hyaluronic acid based gel formulation enriched with NAG （N-acetyl glucosamine） loaded solid lipid nanoparticles against degenerative process of the oral mucosa. Gel formulations were obtained by adding sHA （sodium hyaluronate） into SLN aqueous suspension. Gel performances were evaluated by multi-methodological approach： mucoadhesive and barrier properties evaluation, cell viability. It was shown that gel formulation based sHA, enriched with NAG loaded SLNs, when added as suspension, demonstrated to have a good mucoadhesion profile comparable in terms of tensile work and fracture strength to Carbomer 934 2%. The presence of NAG encapsulated and not in gel formulation enhances also the biocompatibility of the system, demonstrating also to have a proliferative effect. Finally, any barrier property was altered. Finally, results demonstrated that sHA based gel formulation enriched SLNs, demonstrated good mucoadeshion property, comparable to carbopol gel, positive control. The proposed gel formulation enriched with SLNs setting up in this work could be used as innovation strategy to treat oral mucositis.

Nanoparticle‑Loaded Polarized‑Macrophages for Enhanced Tumor Targeting and Cell‑Chemotherapy

Cell therapy is a promising strategy for cancer therapy.However,its therapeutic efficiency remains limited due to the complex and immunosuppressive nature of tumor microenvironments.In this study,the“cell-chemotherapy”strategy was presented to enhance antitumor efficacy.M1-type macrophages,which are therapeutic immune cells with both of immunotherapeutic ability and targeting ability,carried sorafenib(SF)-loaded lipid nanoparticles(M1/SLNPs)were developed.M1-type macrophages were used both as therapeutic tool to provide immunotherapy and as delivery vessel to target deliver SF to tumor tissues for chemotherapy simultaneously.M1-type macrophages were obtained by polarizing macrophages using lipopolysaccharide,and M1/SLNPs were obtained by incubating M1-type macrophages with SLNP.Tumor accumulation of M1/SLNP was increased compared with SLNP(p<0.01),which proved M1/SLNP could enhance tumor targeting of SF.An increased ratio of M1-type macrophages to M2-type macrophages,and the CD3^+CD4^+T cells and CD3^+CD8^+T cell quantities in tumor tissues after treatment with M1/SLNP indicated M1/SLNP could relieve the immunosuppressive tumor microenvironments.The tumor volumes in the M1/SLNP group were significantly smaller than those in the SLNP group(p<0.01),indicating M1/SLNP exhibited enhanced antitumor efficacy.Consequently,M1/SLNP showed great potential as a novel cellchemotherapeutic strategy combining both cell therapy and targeting chemotherapy.

Homogeneous PLGA-lipid nanoparticle as a promising oral vaccine delivery system for ovalbumin

In this study,a polymeric lipid nanoparticle(NP)(simplified as Lipid NP)was reported as a promising oral vaccine delivery system.The Lipid NPs composed of a hydrophobic polymeric poly(D,L-lactide-co-glycolide)(PLGA)core and a surface coating of lipid monolayer.Membrane emulsification technique was used to obtain uniform-sized Lipid NPs.Ovalbumin(OVA)was used as a model vaccine.Compared with the pure PLGA NPs,the Lipid NPs achieved higher loading capacity(LC)and entrapment efficiency(EE)for the encapsulated OVA.An in vitro oral release profile showed that the OVA-Lipid NPs were with lower initial burst and could protect the loaded OVA from the harsh gastrointestinal(GI)environment for a long time.In addition,a human microfold cell(M-cell)transcytotic assay demonstrated that due to a lipid layer structure on the particle surface,the Lipid NPs showed higher affinity to the M-cells.Since the M-cell in the intestinal epithelium played an important role in particle transportation as well as intimately associated with the underlying immune cells,the OVA-Lipid NPs effectively induced mucosal and humoral immune responses.