Formation and stability of multiple-layered liposomes by layer-by-layer electrostatic deposition of biopolymers

Biophysical analysis on molecular interactions between chitosan-coated sinapic acid loaded liposomes and mucin

BACKGROUND

The mucus biomembrane is a primary barrier in delivering drugs to the brain via intranasal delivery. The negatively charged nanoformulations suffer from poor mucoadhesive ability and less retention time in the nasal cavity, which limits further therapeutic efficacy. The positively charged chitosan coating on liposomes may overcome the above issues. Hence, understanding the molecular interactions between the chitosan-coated liposomes and mucin is essential for developing an effective drug delivery system.

METHODS

The molecular interactions of mucin with sinapic acid-loaded liposomes (SA-LPs) and mucin with chitosan-coated sinapic acid-loaded liposomes (SA-CH-LPs) were assessed using different biophysical instrumental analyses by interpreting the UV-Vis spectra and observing the particle size, polydispersity index, surface charge, and rheological behavior.

RESULTS

The mucin interaction with SA-CH-LPs showed increased viscosity as compared to SA-LPs with mucin. Moreover, the mucin interaction with SA-CH-LPs showed stronger mucoadhesive properties as compared to SA-LPs with mucin. The electrostatic interaction between positively charged SA-CH-LPs and negatively charged mucin was responsible for the enhanced mucoadhesive property.

CONCLUSION

The positively charged SA-CH-LPs highly interact with mucin as compared to negatively charged SA-LPs. The mucoadhesive property of SA-CH-LPs could improve the retention of SA in the nasal cavity as compared to SA-LPs. These findings emphasize the importance of chitosan in modulating the mucoadhesive behavior of liposomes.

GENERAL SIGNIFICANCE

Overall, this study helps to understand the molecular interactions and mucoadhesive nature of the chitosan-coated liposomes with mucin, which is essential for biological activity in the physiological environment.

Bitterness-masking assessment of luteolin encapsulated in whey protein isolate-coated liposomes

An unacceptable bitter taste limits the application of luteolin in healthier food systems. In this study, a bitterness-masking assessment was performed on whey protein isolate-coated liposomes loaded with luteolin (WPI-coated liposomes) using an electronic tongue and human sensory test. The physical properties of the WPI-coated colloidal nanocarrier were characterized by zeta potential, average diameter, distribution, and morphology analyses. The results indicated that WPI-coated nanocarrier systems exhibited a uniformly dispersed distribution and spherical morphology. After the comparison of the bitterness value, the bitterness-reducing effect of 5% WPI-coated liposomes was the most significant and reduced the bitterness of luteolin by 75%. Raman spectroscopy and X-ray diffraction analysis demonstrated that the decoration of WPI on the liposomes reduced the free motion of lipid molecules. This promoted the ordering at the polar headgroup area and hydrophobic core of the lipid bilayer, which explained why luteolin-loaded liposomes (uncoated liposomes) and WPI-coated liposomes could reduce the bitterness of luteolin from the perspective of bitter molecular groups. Combined with the Raman spectral data, the bilayer rigidity of 5% WPI-coated liposomes was positively responsive to the stabilization of uncoated liposomes against storage and resistance ability against surfactants. It was proven that the emergence of the surface modification of the WPI coating enhanced the stability of uncoated liposomes. These results may contribute to the use of WPI-coated liposomes as prospective candidates for effective delivery of the bioactive bitter substance in nutraceuticals and functional foods.

Venturi-based rapid expansion of supercritical solution (Vent-RESS): synthesis of liposomes for pH-triggered delivery of hydrophilic and lipophilic bioactives

Multivitamin-loaded and surface-modified liposomes tailored for simultaneous intestinal delivery of both lipophilic and hydrophilic bioactives were synthesized from sunflower phosphatidylcholine (SFPC). Liposomes (SL) were generated with the aid of a novel, organic solvent free, and environmentally benign process which utilizes venturi-based rapid expansion of supercritical solution (Vent-RESS). Vitamins E and C were used as model lipophilic and hydrophilic bioactives and demonstrated an average encapsulation efficiency of 92 and 70 %, respectively. Synthesized liposomes were coated with a pH-responsive double-wall of chitosan and β-lactoglobulin (βlg-Cs-SL) to develop a biocompatible vehicle for pH-triggered delivery of bioactive cargo(s). To compare the efficacy of this newly developed dual-coating, SL was also coated with a commercially available pH responsive polymer, Eudragit^® S100 (Eu-SL). No organic solvent was used during the surface coating of SLs with these two different types of enteric coatings. The performance of these two coatings was studied by conducting morphological characterization through diameter and ζ-potential measurements along with confocal laser scanning and freeze-fracture cryogenic scanning electron microscopies. The stability of coated and uncoated SFPC liposomes was determined in simulated gastrointestinal fluids. For βlg-Cs-SL and Eu-SL, after 2 h of incubation in simulated gastric condition, less than 5 % of the encapsulated vitamins C and E were released, whereas for SL, 41 and 28 % of vitamins C and E were released within 2 h of incubation period. In simulated intestinal fluid, coated liposomes released most of their remaining payload when incubated for 4 h. The newly developed dual coating was found to be as effective as its commercially available counterpart, Eudragit^® S100 coating; nevertheless, the biocompatible, non-toxic, and non-synthetic nature of this coating makes it an attractive alternative. Modeling the release kinetics of vitamins from coated liposome showed that the release of payload from surface coated liposomes proceeded through a multistep structural disintegration involving both Fickian and non-Fickian types of diffusion. The ability of these surface-coated liposomes to maintain structural integrity under the gastric condition followed by site-specific, pH-triggered release of encapsulated cargo in the intestine will make them highly suitable for oral administration of bioactive compounds in pharmaceutical and food applications.

Optimization of n-Hexane-Acetone System for Extraction of Phosphatidylcholine and Phosphatidylethanolamine by Response Surface Methodology

Eggs are nutritious and cheap and easily available. Egg yolk is one of the sources of phosphatidylcholine (PC) and phosphatidylethanolamine (PE). PC and PE have good emulsifying properties, and they are widely used and in high demand for pharmaceutical, feed and cosmetic applications. Red cordyceps egg yolk powder (RCEYP) was selected as the raw material to obtain high content of PC and PE by ethanol extraction and low temperature cryoprecipitation in n-hexane-acetone system (HAS), in which the process conditions of PC and PE extraction by HAS process were optimized. The phospholipids were quantified by high performance liquid chromatography (HPLC) with evaporative light scattering detector (ELSD). The effects of freezing time, material-liquid ratio, acetone washing times, solvent ratio of n-hexane to acetone and freezing temperature on the PC and PE contents and the phospholipid yield were investigated. The optimal conditions for the extraction of PC and PE from RCEYP by HAS were determined by Box-Behnken design (BBD) as follows: the solvent ratio of n-hexane to acetone was 1:6, the freezing time was 11.31 h, and the freezing temperature was -19℃. The total content of (PC+PE) in the phospholipids precipitated under these conditions amounted to 96.16%, of which 81.12% was PC and 15.04% was PE.

Polymer-Modified Liposomes for Drug Delivery: From Fundamentals to Applications

Liposomes are highly advantageous platforms for drug delivery. To improve the colloidal stability and avoid rapid uptake by the mononuclear phagocytic system of conventional liposomes while controlling the release of encapsulated agents, modification of liposomes with well-designed polymers to modulate the physiological, particularly the interfacial properties of the drug carriers, has been intensively investigated. Briefly, polymers are incorporated into liposomes mainly using “grafting” or “coating”, defined according to the configuration of polymers at the surface. Polymer-modified liposomes preserve the advantages of liposomes as drug-delivery carriers and possess specific functionality from the polymers, such as long circulation, precise targeting, and stimulus-responsiveness, thereby resulting in improved pharmacokinetics, biodistribution, toxicity, and therapeutic efficacy. In this review, we summarize the progress in polymer-modified liposomes for drug delivery, focusing on the change in physiological properties of liposomes and factors influencing the overall therapeutic efficacy.

Antimicrobial Activity Enhancers: Towards Smart Delivery of Antimicrobial Agents

The development of effective treatments against infectious diseases is an extensive and ongoing process due to the rapid adaptation of bacteria to antibiotic-based therapies. However, appropriately designed activity enhancers, including antibiotic delivery systems, can increase the effectiveness of current antibiotics, overcoming antimicrobial resistance and decreasing the chance of contributing to further bacterial resistance. The activity/delivery enhancers improve drug absorption, allow targeted antibiotic delivery, improve their tissue and biofilm penetration and reduce side effects. This review provides insights into various antibiotic activity enhancers, including polymer, lipid, and silver-based systems, designed to reduce the adverse effects of antibiotics and improve formulation stability and efficacy against multidrug-resistant bacteria.

Polyelectrolyte Multi-Layered Griseofulvin Nanoparticles: Conventional versus Continuous In-Situ Layer-by-Layer Fabrication

Polyelectrolyte multilayers are promising drug carriers with potential applications in the delivery of poorly soluble drugs. Furthermore, the polyelectrolyte multilayer contributes towards electrostatic interactions, which enhances the physical and chemical stability of colloids when compared to those prepared by other approaches. The aim of this work was to generate a polyelectrolyte multilayer on well characterised nanoparticles of the poorly water-soluble drug, griseofulvin. Griseofulvin (GF) nanoparticles (300 nm) were produced by wet bead milling, bearing a negative surface charge due to the use of poly(sodium 4-styrenesulfonate) (PSS) as a stabiliser. Six further layers of alternating chitosan and PSS polyelectrolyte multilayer were successfully generated at the particle surface either via use of: (1) the conventional method of adding excess coating polymer followed by centrifugation, or (2) the continuous in situ approach of adding sufficient amount of coating polymer. The continuous in situ method was designed de novo by the consecutive addition of polymers under high shear rate mixing. In comparison to the continuous in situ method, the conventional method yielded nanoparticles of smaller size (282 ±9 nm vs. 497 ±34 nm) and higher stability by maintaining its size for 6 months. In conclusion, the parent griseofulvin nanosuspension proved to be a suitable candidate for the polyelectrolyte multilayer fabrication providing an avenue for a bespoke formulation with versatile and potentially enhanced drug delivery properties.

Towards the systematic design of multilayer O/W emulsions with tannic acid as an interfacial antioxidant

This work discusses the possibility of designing multilayer oil-in-water emulsions to introduce the maximum possible amount of an antioxidant at the droplet interfaces for the optimal protection of a linseed oil core against oxidation, using a systematic three-step colloidal procedure. An antioxidant (here Tannic Acid - TA) is chosen and its interactions with a primary emulsifier (here Bovine Serum Albumin - BSA) and several polysaccharides are first examined in solution using turbidity measurements. As a second step, LbL deposition on solid surfaces is used to determine which of the polysaccharides to combine with BSA and tannic acid in a multilayer system to ensure maximum presence of tannic acid in the films. From UV-vis and polarization modulation infrared reflection-absorption (PM-IRRAS) spectroscopic measurements it is suggested that the best components to use in a multilayer emulsion droplet, together with BSA and TA, are chitosan and pectin. BSA, chitosan and pectin are subsequently used for the formation of three-layer linseed oil emulsions, and tannic acid is introduced into any of the three layers as an antioxidant. The effect of the exact placement of tannic acid on the oxidative stabilization of linseed oil is assessed by monitoring the fluorescence of Nile red, dissolved in the oil droplets, under the attack of radicals generated in the aqueous phase of the emulsion. From the results it appears that the three-stage procedure presented here can serve to identify successful combinations of interfacial components of multilayer emulsions. It is also concluded that the exact interfacial placement of the antioxidant plays an important role in the oxidative stabilization of the valuable oil core.

Formulation of Piperine-Chitosan-Coated Liposomes: Characterization and In Vitro Cytotoxic Evaluation

The present research work is designed to prepare and evaluate piperine liposomes and piperine–chitosan-coated liposomes for oral delivery. Piperine (PPN) is a water-insoluble bioactive compound used for different diseases. The prepared formulations were evaluated for physicochemical study, mucoadhesive study, permeation study and in vitro cytotoxic study using the MCF7 breast cancer cell line. Piperine-loaded liposomes (PLF) were prepared by the thin-film evaporation method. The selected liposomes were coated with chitosan (PLFC) by electrostatic deposition to enhance the mucoadhesive property and in vitro therapeutic efficacy. Based on the findings of the study, the prepared PPN liposomes (PLF3) and chitosan coated PPN liposomes (PLF3C1) showed a nanometric size range of 165.7 ± 7.4 to 243.4 ± 7.5, a narrow polydispersity index (>0.3) and zeta potential (−7.1 to 29.8 mV). The average encapsulation efficiency was found to be between 60 and 80% for all prepared formulations. The drug release and permeation study profile showed biphasic release behavior and enhanced PPN permeation. The in vitro antioxidant study results showed a comparable antioxidant activity with pure PPN. The anticancer study depicted that the cell viability assay of tested PLF3C2 has significantly (p < 0.001)) reduced the IC₅₀ when compared with pure PPN. The study revealed that oral chitosan-coated liposomes are a promising delivery system for the PPN and can increase the therapeutic efficacy against the breast cancer cell line.

Polyelectrolyte Multilayers on Soft Colloidal Nanosurfaces: A New Life for the Layer-By-Layer Method

The Layer-by-Layer (LbL) method is a well-established method for the assembly of nanomaterials with controlled structure and functionality through the alternate deposition onto a template of two mutual interacting molecules, e.g., polyelectrolytes bearing opposite charge. The current development of this methodology has allowed the fabrication of a broad range of systems by assembling different types of molecules onto substrates with different chemical nature, size, or shape, resulting in numerous applications for LbL systems. In particular, the use of soft colloidal nanosurfaces, including nanogels, vesicles, liposomes, micelles, and emulsion droplets as a template for the assembly of LbL materials has undergone a significant growth in recent years due to their potential impact on the design of platforms for the encapsulation and controlled release of active molecules. This review proposes an analysis of some of the current trends on the fabrication of LbL materials using soft colloidal nanosurfaces, including liposomes, emulsion droplets, or even cells, as templates. Furthermore, some fundamental aspects related to deposition methodologies commonly used for fabricating LbL materials on colloidal templates together with the most fundamental physicochemical aspects involved in the assembly of LbL materials will also be discussed.

Biopolymer-liposome hybrid systems for controlled delivery of bioactive compounds: Recent advances

Conventional liposomes still face many challenges associated with the poor physical and chemical stability, considerable loss of encapsulated cargo, lack of stimulus responsiveness, and rapid elimination from blood circulation. Integration of versatile functional biopolymers has emerged as an attractive strategy to overcome the limitation of usage of liposomes. This review comprehensively summarizes the most recent studies (2015-2020) and their challenges aiming at the exploration of biopolymer-liposome hybrid systems, including surface-modified liposomes, biopolymer-incorporated liposomes, guest-in-cyclodextrin-in-liposome, liposome-in-hydrogel, liposome-in-film, and liposome-in-nanofiber. The physicochemical principles and key technical information underlying the combined strategies for the fabrication of polymeric liposomes, the advantages and limitations of each of the systems, and the stabilization mechanisms are discussed through various case studies. Special emphasis is directed toward the synergistic efficiencies of biopolymers and phospholipid bilayers on encapsulation, protection, and controlled delivery of bioactives (e.g., vitamins, carotenoids, phenolics, peptides, and other health-related compounds) for the biomedical, pharmaceutical, cosmetic, and functional food applications. The major challenges, opportunities, and possible further developments for future studies are also highlighted.

Molecular Design of Layer-by-Layer Functionalized Liposomes for Oral Drug Delivery

Liposomes are small spherical vesicles composed mainly of phospholipids and cholesterol. Over the years, a number of liposomal formulations have shown clinical promise, but the use of liposomes in oral drug delivery is limited. This is partly due to the vulnerability of conventional liposomes to the detrimental effect of gastrointestinal destabilizing factors and also to the poor efficiency in intestinal absorption of liposomes. Some of these issues can be ameliorated using the layer-by-layer (LbL) assembly technology, which has been widely applied to modify the surface of various nanoparticulate systems. Discussions about LbL functionalization of liposomes as oral drug carriers, however, are scant in the literature. To fill this gap, this review presents an overview of the roles of LbL functionalization in the development of liposomes, followed by a discussion about major principles of molecular design and engineering of LbL-functionalized liposomes for oral drug delivery. Regarding the versatility offered by LbL assembly, it is anticipated that LbL-functionalized liposomes may emerge as one of the important carriers for oral drug administration in the future.

Surface decoration of neohesperidin-loaded nanoliposome using chitosan and pectin for improving stability and controlled release

The aim of this study was to improve the physicochemical stability of neohesperidin (NH) using nanoliposomal encapsulation in association with surface decoration strategy employing chitosan (CH) and pectin (P). Different nanoliposomal systems, i.e. NH-loaded nanoliposome (NH-NL), CH-coated NH-NL (CH-NH-NL), and P-coated CH-NH-NL (P-CH-NH-NL) were characterized through DLS, HPLC, TEM, and FTIR. The results confirmed good encapsulation efficiency (>90%) and successful layer formation with nano-sized and spherical carrier. Both CH-NL and P-CH-NL exhibited better physicochemical stability than NL under storage, thermal, pH, ionic, UV, oxidative, and serum conditions. In vitro mucin adsorption study revealed that CH-NL (60%) was more effective in mucoadhesion followed by P-CH-NL (46%) and NL (41%). Furthermore, P-CH-NL showed better performance in NH retention under different food simulants compared to CH-NH-NL and NH-NL, in which the release was mainly governed by the diffusion process. Thus, the P-CH conjugated nanoliposome could be a promising nano-carrier for neohesperidin.

Improving the physicochemical stability and functionality of nanoliposome using green polymer for the delivery of pelargonidin-3-O-glucoside

This study aimed to improve the physicochemical stability of nanoliposome (NL) with enhanced functionality for the delivery of Pelargonidin-3-O-glucoside (P3G) using biopolymers, i.e. chitosan (CH) and pectin (P). In this study, we successfully developed stabilized liposomal carriers, i.e. CH-conjugated NL (CH-NL) and P-conjugated CH-NL (P-CH-NL) using an optimum concentration of CH (0.6 wt%) and P (0.5 wt%). Results revealed that P-CH-NL had better physical stability to salt and pH with maximum P3G retention (>97%) under oxidative, thermal, and UV conditions. Nanoliposomes were more stable under refrigerated-storage and ensured high P3G retention (>96%). In vitro mucoadhesion study revealed that CH-NL had better mucin adsorption efficiency (59.72%) followed by P-CH-NL and NL. Furthermore, CH-NL and P-CH-NL alternatively had better stability to serum than NL. Taken together, the stabilization of nanoliposome using chitosan and pectin can be a promising approach for the delivery of hydrophilic compounds in association with enhanced stability and functionality.

Enhancing Efficacy, Performance, and Reliability of Cannabis Edibles: Insights from Lipid Bioavailability Studies

The legal sale of cannabis-enriched foods and beverages for medical or recreational purposes is increasing in many states and countries, especially in North America and Europe. These food-based cannabis delivery systems vary considerably in their compositions and structures, ranging from low-viscosity watery beverages to solid fatty chocolates. The rate and extent of release of the bioactive components in cannabis within the human gastrointestinal tract (GIT) affect their health and psychoactive effects. Studies with other types of hydrophobic bioactives, such as nutraceuticals and vitamins, have shown that food composition and structure have a major impact on their bioaccessibility, transformation, and absorption within the GIT, thereby influencing their bioavailability and bioactivity. This review outlines how insights on the bioavailability of other lipophilic bioactives can be used to facilitate the design of more efficacious and consistent cannabis-enriched products intended for oral consumption. In particular, the importance of food-matrix composition (such as fat type and level) and structural organization (such as fat domain dimensions) are discussed.

Nanostructured Lipid-Based Delivery Systems as a Strategy to Increase Functionality of Bioactive Compounds

Acquisition of a healthy lifestyle through diet has driven the food manufacturing industry to produce new food products with high nutritional quality. In this sense, consumption of bioactive compounds has been associated with a decreased risk of suffering chronic diseases. Nonetheless, due to their low solubility in aqueous matrices, high instability in food products during processing and preparation as well as poor bioavailability, the use of such compounds is sometimes limited. Recent advancements in encapsulation and protection of bioactive compounds has opened new possibilities for the development of novel food products. In this direction, the present review is attempting to describe encapsulation achievements, with special attention to nanostructured lipid-based delivery systems, i.e., nanoemulsions, multi-layer emulsions and liposomes. Functionality of bioactive compounds is directly associated with their bioavailability, which in turn is governed by several complex processes, including the passage through the gastrointestinal tract and transport to epithelial cells. Therefore, an overview of recent research on the properties of these nanostructured lipid-based delivery systems with a strong impact on the functionality of bioactive compounds will be also provided. Nanostructured lipid-based delivery systems might be used as a potential option to enhance the solubility, stability, absorption and, ultimately, functionality of bioactive compounds. Several studies have been performed in this line, modifying the composition of the nanostructures, such as the lipid-type or surfactants. Overall, influencing factors and strategies to improve the efficacy of encapsulated bioactive compounds within nanostructures have been successfully identified. This knowledge can be used to design effective targeted nanostructured lipid-based delivery systems for bioactive compounds. However, there is still a lack of information on food interactions, toxicity and long-term consumption of such nanostructures.

Nanodelivery of Natural Antioxidants: An Anti-aging Perspective

The aging process is known to be associated with heightened oxidative stress and related systemic inflammation. Therefore, antioxidant supplementation is regarded as a promising strategy to combat aging and associated pathological conditions. Food-grade antioxidants from plant-derived extracts are the most common ingredients of these supplements. Phyto-bioactive compounds such as curcumin, resveratrol, catechins, quercetin are among the most commonly applied natural compounds used as potential modulators of the free radical-induced cellular damages. The therapeutic potential of these compounds is, however, restricted by their low bioavailability related to poor solubility, stability, and absorbance in gastrointestinal tract. Recently, novel nanotechnology-based systems were developed for therapeutic delivery of natural antioxidants with improved bioavailability and, consequently, efficacy in clinical practice. Such systems have provided many benefits in preclinical research over the conventional preparations, including superior solubility and stability, extended half-life, improved epithelium permeability and bioavailability, enhanced tissue targeting, and minimized side effects. The present review summarizes recent developments in nanodelivery of natural antioxidants and its application to combat pathological conditions associated with oxidative stress.

Doxorubicin/cisplatin co-loaded hyaluronic acid/chitosan-based nanoparticles for in vitro synergistic combination chemotherapy of breast cancer

Combination chemotherapy has attracted more and more attention in the field of anticancer treatment. Herein, a synergetic targeted combination chemotherapy of doxorubicin (DOX) and cisplatin in breast cancer was realized by HER2 antibody-decorated nanoparticles assembled from aldehyde hyaluronic acid (AHA) and hydroxyethyl chitosan (HECS). Cisplatin and DOX were successively conjugated onto AHA through chelation and Schiff's base reaction, respectively, forming DOX/cisplatin-loaded AHA inner core. The core was sequentially complexed with HECS and targeting HER2 antibody-conjugated AHA. The formed near-spherical nanoplatform had an average size of ∼160 nm and a zeta potential of -28 mV and displayed pH-responsive surface charge reversal and drug release behaviors. HER2 receptor-mediated active targeting significantly enhanced the cellular uptake of nanoplatform. Importantly, DOX and cisplatin exhibited a synergistic cell-killing effect in human breast cancer MCF-7 cells. These results clearly indicate that the novel nanoplatform is promising for synergistic combination chemotherapy of breast cancer.

Physicochemical mechanisms of different biopolymers' (lysozyme, gum arabic, whey protein, chitosan) adsorption on green tea extract loaded liposomes

Having various domains of applicability, liposomes have been the issue of many studies since 1960s. Kinetically stable nature of liposomes required incorporation of other substituents to gain storage stability and interaction of liposomes with polymers, electrolytes, proteins or lipids still requires further investigation to explain the underlying mechanism. In this study, polyphenol-rich green tea extract was encapsulated into liposomes by means of microfluidization in two different aqueous media (pH = 3.8 acetate buffer and pH = 6.5 distilled water). Antioxidant loaded vesicles were further mixed with anionic biopolymers (gum arabic, whey protein) and cationic biopolymers (lysozyme, chitosan) separately. The physical and chemical interactions between liposomes and biopolymers were rationalized by particle size, zeta potential, transmission electron microscopy, total phenolic content and antioxidant activity measurements during 28-days storage at 4 °C. Experimental results indicated that the biopolymer incorporated liposomes showed better stability compared to control liposomes during storage, developing resistance against changes in particle size and zeta potential. On the other hand, biopolymer interaction mechanisms were shown to be different for different biopolymers. As was also proved by transmission electron microscopy, lysozyme was absorbed into the liposomes while gum arabic, whey protein and chitosan were adsorbed on the vesicle surface to shield green tea extract loaded liposomes.

Interaction between Gemini Dodecyl O-Glucosides-Based Multilayer Vesicles and β-Lactoglobulin: The Dominant Role of Surface Charge

Novel Gemini dodecyl O-glucoside-based primary, secondary, and tertiary vesicles were developed in this work utilizing layer-by-layer deposition of polysaccharides (e.g., sodium carboxymethyl cellulose and chitosan), and their interaction with β-lactoglobulin (BLG) was carefully investigated. The increase of polysaccharide layers on primary vesicles led to a monotonic increase in size and consecutive reversal of surface charge. Polysaccharide deposition significantly retarded the vesicle aggregation and degradation of entrapped catechin laurate during storage. Steady-state fluorescence, isothermal titration calorimetry, and protein precipitation analyses revealed the surface charge dependence of the interactions between vesicles and a model milk protein BLG, which were much stronger when they were charged oppositely than when they presented the same type of surface charge. It was highlighted that the surface charge of vesicles could be tuned by differently charged coatings to accommodate to that of the milk proteins in the food matrix. This work will contribute to the practical application of niosomal vesicles loaded with bioactive compounds to fortify dairy products.

Encapsulation, protection, and delivery of bioactive proteins and peptides using nanoparticle and microparticle systems: A review

There are many examples of bioactive proteins and peptides that would benefit from oral delivery through functional foods, supplements, or medical foods, including hormones, enzymes, antimicrobials, vaccines, and ACE inhibitors. However, many of these bioactive proteins are highly susceptible to denaturation, aggregation or hydrolysis within commercial products or inside the human gastrointestinal tract (GIT). Moreover, many bioactive proteins have poor absorption characteristics within the GIT. Colloidal systems, which contain nanoparticles or microparticles, can be designed to encapsulate, retain, protect, and deliver bioactive proteins. For instance, a bioactive protein may have to remain encapsulated and stable during storage and passage through the mouth and stomach, but then be released within the small intestine where it can be absorbed. This article reviews the application of food-grade colloidal systems for oral delivery of bioactive proteins, including microemulsions, emulsions, nanoemulsions, solid lipid nanoparticles, multiple emulsions, liposomes, and microgels. It also provides a critical assessment of the characteristics of colloidal particles that impact the effectiveness of protein delivery systems, such as particle composition, size, permeability, interfacial properties, and stability. This information should be useful for the rational design of medical foods, functional foods, and supplements for effective oral delivery of bioactive proteins.

Layer-by-layer assembly of graphene oxide on thermosensitive liposomes for photo-chemotherapy

Stimuli responsive polyelectrolyte nanoparticles have been developed for chemo-photothermal destruction of breast cancer cells. This novel system, called layer by layer Lipo-graph (LBL Lipo-graph), is composed of alternate layers of graphene oxide (GO) and graphene oxide conjugated poly (l-lysine) (GO-PLL) deposited on cationic liposomes encapsulating doxorubicin. Various concentrations of GO and GO-PLL were examined and the optimal LBL Lipo-graph was found to have a particle size of 267.9 ± 13 nm, zeta potential of +43.9 ± 6.9 mV and encapsulation efficiency of 86.4 ± 4.7%. The morphology of LBL Lipo-graph was examined by cryogenic-transmission electron microscopy (Cryo-TEM), atomic force microcopy (AFM) and scanning electron microscopy (SEM). The buildup of LBL Lipo-graph was confirmed via ultraviolet-visible (UV-Vis) spectrophotometry, thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) analysis. Infra-red (IR) response suggests that four layers are sufficient to induce a gel-to-liquid phase transition in response to near infra-red (NIR) laser irradiation. Light-matter interaction of LBL Lipo-graph was studied by calculating the absorption cross section in the frequency domain by utilizing Fourier analysis. Drug release assay indicates that the LBL Lipo-graph releases much faster in an acidic environment than a liposome control. A cytotoxicity assay was conducted to prove the efficacy of LBL Lipo-graph to destroy MD-MB-231 cells in response to NIR laser emission. Also, image stream flow cytometry and two photon microcopy provide supportive data for the potential application of LBL Lipo-graph for photothermal therapy. Study results suggest the novel dual-sensitive nanoparticles allow intracellular doxorubin delivery and respond to either acidic environments or NIR excitation.

STATEMENT OF SIGNIFICANCE

Stimuli sensitive hybrid nanoparticles have been synthesized using a layer-by-layer technique and demonstrated for dual chemo-photothermal destruction of breast cancer cells. The hybrid nanoparticles are composed of alternating layers of graphene oxide and graphene oxide conjugated poly-l-lysine coating the surface of a thermosensitive cationic liposome containing doxorubicin as a core. Data suggests that the hybrid nanoparticles may offer many advantages for chemo-photothermal therapy. Advantages include a decrease of the initial burst release which may result in the reduction in systemic toxicity, increase in pH responsivity around the tumor environment and improved NIR light absorption.

Delivery by Design (DbD): A Standardized Approach to the Development of Efficacious Nanoparticle- and Microparticle-Based Delivery Systems

The design and development of nanoparticle- and microparticle-based delivery systems for the encapsulation, protection, and controlled release of active agents has grown considerably in the agrochemical, cosmetic, food, personal care, and pharmaceutical industries. These colloidal delivery systems can be utilized to overcome problems such as poor solubility, low activity, and chemical instability of active agents, as well as to create novel functional attributes such as controlled or targeted delivery. The purpose of this article is to develop a systematic approach, referred to as "delivery-by-design" (DbD), to make the design and fabrication process more efficient and effective. Initially, a brief review of some of the challenges associated with incorporating active agents into commercial products is given, and then an overview of different kinds of simple and complex colloidal delivery systems is given. The DbD approach is then presented as a series of stages: (1) definition of the molecular and physicochemical properties of the active agent; (2) definition of the required physicochemical, sensory, and functional attributes of the end-product; (3) specification of the required attributes of the colloidal delivery system; (4) specification of particle properties and delivery system selection; (5) optimization of delivery system manufacturing process; (6) establishment and implementation of delivery system testing protocol; and (7) optimization of delivery system performance. Utilization of the DbD approach may lead to more rapid design of efficacious and economically viable colloidal delivery systems for commercial applications.

Physical–chemical stability and in vitro digestibility of hybrid nanoparticles based on the layer-by-layer assembly of lactoferrin and BSA on liposomes

Novel hybrid nanoparticles fabricated by the layer-by-layer deposition of lactoferrin and BSA on nanoliposomes showed a higher physical–chemical stability and digestibility than bare liposomes.

Change of Multiple-Layered Phospholipid Vesicles Produced by Electrostatic Deposition of Polymers during Storage

In this study, 1 wt% lecithin (–), chitosan (+), and λ-carrageenan (–) were prepared to manufacture multiple-layered liposomes with optimal formulations developed in a previous study by using layer-by-layer electrostatic deposition. We observed their particle size, ζ-potential, sedimentation behavior, and microstructure for 6 weeks. Multiple-layered liposomes were quenched with calcein to evaluate stability in terms of factors such as encapsulation efficiency and released amount of calcein. The particle size of multi-layered liposomes increased with storage periods and the ζ-potential of multiple-layered liposomes gained a neutral charge. Interestingly, negatively charged layered liposomes were smaller than positively charged layered liposomes and showed a lower polydispersity index. Moreover, the ζ-potential did not apparently change compared to positively charged layered liposomes. For the calcein release study, multiple-layered liposomes significantly sustained quenched calcein more than that observed using non-layered liposomes. This study showed that it was possible to increase the thickness of the liposome surface and to manipulate its charge using chitosan and λ-carrageenan through electrostatic deposition. Results showed that manufacturing negatively charged multiple-layer (over 4-layer) liposomes with charged biopolymer improved the physicochemical stability of liposomes.

Physical and biological characterization of sericin-loaded copolymer liposomes stabilized by polyvinyl alcohol

Sericin protein (SP) is widely used as a nutrient biomaterial for biomedical and cosmeceutical applications although it shows low stability to heat and light. To overcome these problems and add value to wastewater from the silk industry, sericin protein was recovered as sericin-loaded copolymer-liposomes (SP-PVA-LP), prepared through thin film hydration. The size and morphology of the liposomes were investigated using dynamic light scattering (DLS), and electron microscopy (SEM and TEM). The particle size, liposome surface morphology and encapsulation efficiency of SP were dependent on PVA concentration. The hydrodynamic size of the nanoparticles was between 200 and 400nm, with the degree of negative charge contingent on sericin loading. SEM and TEM images confirmed the mono-dispersity, and spherical nature of the particles, with FTIR measurements confirming the presence of surface bound PVA. Exposure of liposomes to 500ppm sericin highlighted a dependence of encapsulation efficiency on PVA content; 2% surface PVA proved the optimal level for sericin loading. Cytotoxicity and viability assays revealed that SP-loaded surface modified liposomes promote cellular attachment and proliferation of human skin fibroblasts without adverse toxic effects. Surface modified copolymer liposomes show high performance in maintaining structural stability, and promoting enhancements in the solubility and bio-viability of sericin. Taken together, these biocompatible constructs allow for effective controlled release, augmenting sericin activity and resulting in effective drug delivery systems.

Modification of Spherical Polyelectrolyte Brushes by Layer-by-Layer Self-Assembly as Observed by Small Angle X-ray Scattering

Multilayer modified spherical polyelectrolyte brushes were prepared through alternate deposition of positively charged poly(allylamine hydrochloride) (PAH) and negatively charged poly-l-aspartic acid (PAsp) onto negatively charged spherical poly(acrylic acid) (PAA) brushes (SPBs) on a poly(styrene) core. The charge reversal determined by the zeta potential indicated the success of layer-by-layer (LBL) deposition. The change of the structure during the construction of multilayer modified SPBs was observed by small-angle X-ray scattering (SAXS). SAXS results indicated that some PAH chains were able to penetrate into the PAA brush for the PAA-PAH double-layer modified SPBs whereas part of the PAH moved towards the outer layer when the PAsp layer was loaded to form a PAA-PAH-PAsp triple-layer system. The multilayer modified SPBs were stable upon changing the pH (5 to 9) and ionic strength (1 to 100 mM). The triple-layer modified SPBs were more tolerated to high pH (even at 11) compared to the double-layer ones. SAXS is proved to be a powerful tool for studying the inner structure of multilayer modified SPBs, which can establish guidelines for the a range of potential applications of multilayer modified SPBs.

Fortification of dark chocolate with spray dried black mulberry (Morus nigra) waste extract encapsulated in chitosan-coated liposomes and bioaccessability studies

Fine-disperse anionic liposomes containing black mulberry (Morus nigra) extract (BME) were prepared by high pressure homogenization at 25,000 psi. Primary liposomes were coated with cationic chitosan (0.4, w/v%) using the layer-by-layer depositing method and mixed with maltodextrin (MD) (20, w/v%) prior to spray drying. After that, spray dried liposomal powders containing BME were added to chocolates with alkalization degrees (pH 4.5, 6, 7.5) at conching temperatures of 40 °C, 60 °C, and 80 °C. The results showed that, compared to spray dried extract, chitosan coated liposomal powders provided better protection of anthocyanin content in both increased temperature and pH. In addition, encapsulation in liposomes enhanced in vitro bioaccessability of anthocyanins. Chocolate was fortified with encapsulated anthocyanins maximum 76.8% depending on conching temperature and pH.

Chitosan coated vancomycin hydrochloride liposomes: Characterizations and evaluation

The present work evaluated the feasibility of chitosan coated liposomes (c-Lips) for the intravenous delivery of vancomycin hydrochloride (VANH), a water-soluble antibiotic for the treatment of gram-positive bacterial infections like osteomyelitis, arthritis, endocarditis, pneumonia, etc. The objective of this research was to develop a suitable drug delivery system in vivo which could improve therapeutic efficacy and decrease side effects especially nephrotoxicity. Firstly, the vancomycin hydrochloride liposomes (VANH-Lips) were prepared by modified reverse phase evaporation method, then the chitosan wrapped vancomycin hydrochloride liposomes (c-VANH-Lips) nanosuspension was formulated by the method of electrostatic deposition. Based on the optimized results of single-factor screening experiment, the c-VANH-Lips were found to be relatively uniform in size (220.40 ± 3.56 nm) with a narrow polydispersity index (PI) (0.21 ± 0.03) and a positive zeta potential (25.7 ± 1.12 mV). The average drug entrapment efficiency (EE) and drug loading (DL) were 32.65 ± 0.59% and 2.18 ± 0.04%, respectively. The in vitro release profile of c-VANH-Lips possessed a sustained release Characterization and the release behavior was in accordance with the Weibull equation. Hemolysis experiments showed that its intravenous injection had preliminary safety. In vivo, after intravenous injection to mice, c-VANH-Lips showed a longer retention time and higher AUC values compared with the VANH injection (VANH-Inj) and VANH-Lips. In addition, biodistribution results clearly demonstrated that c-VANH-Lips preferentially decreased the drug distribution in kidney of mice after intravenous injection. These results revealed that injectable c-VANH-Lips may serve as a promising carrier for VANH to increase therapeutic efficacy on gram-positive bacterial infections and reduce nephrotoxicity, which provides significantly clinical value for long-term use of VANH.

Encapsulation, protection, and release of hydrophilic active components: potential and limitations of colloidal delivery systems

There have been major advances in the development of edible colloidal delivery systems for hydrophobic bioactives in recent years. However, there are still many challenges associated with the development of effective delivery systems for hydrophilic bioactives. This review highlights the major challenges associated with developing colloidal delivery systems for hydrophilic bioactive components that can be utilized in foods, pharmaceuticals, and other products intended for oral ingestion. Special emphasis is given to the fundamental physicochemical phenomena associated with encapsulation, stabilization, and release of these bioactive components, such as solubility, partitioning, barriers, and mass transport processes. Delivery systems suitable for encapsulating hydrophilic bioactive components are then reviewed, including liposomes, multiple emulsions, solid fat particles, multiple emulsions, biopolymer particles, cubosomes, and biologically-derived systems. The advantages and limitations of each of these delivery systems are highlighted. This information should facilitate the rational selection of the most appropriate colloidal delivery systems for particular applications in the food and other industries.

Understanding nanoparticle cellular entry: A physicochemical perspective

Understanding interactions between nanoparticles (NPs) with biological matter, particularly cells, is becoming increasingly important due to their growing application in medicine and materials, and consequent biological and environmental exposure. For NPs to be utilised to their full potential, it is important to correlate their functional characteristics with their physical properties, which may also be used to predict any adverse cellular responses. A key mechanism for NPs to impart toxicity is to gain cellular entry directly. Many parameters affect the behaviour of nanomaterials in a cellular environment particularly their interactions with cell membranes, including their size, shape and surface chemistry as well as factors such as the cell type, location and external environment (e.g. other surrounding materials, temperature, pH and pressure). Aside from in vitro and in vivo experiments, model cell membrane systems have been used in both computer simulations and physicochemical experiments to elucidate the mechanisms for NP cellular entry. Here we present a brief overview of the effects of NPs physical parameters on their cellular uptake, with focuses on 1) related research using model membrane systems and physicochemical methodologies; and 2) proposed physical mechanisms for NP cellular entrance, with implications to their nanotoxicity. We conclude with a suggestion that the energetic process of NP cellular entry can be evaluated by studying the effects of NPs on lipid mesophase transitions, as the molecular deformations and thus the elastic energy cost are analogous between such transitions and endocytosis. This presents an opportunity for contributions to understanding nanotoxicity from a physicochemical perspective.

Improved stability and skin permeability of sodium hyaluronate-chitosan multilayered liposomes by Layer-by-Layer electrostatic deposition for quercetin delivery

Layer-by-Layer (LbL) technology, based on the electrostatic interaction of polyelectrolytes, is used to improve the stability of drug delivery systems. In the present study, we developed multilayered liposomes with up to 10 alternating layers based on LbL deposition of hyaluronate-chitosan for transdermal delivery. Dihexadecyl phosphate was used to provide liposomes with a negative charge; the liposomes were subsequently coated with cationic chitosan (CH) followed by anionic sodium hyaluronate (HA). The resulting particles had a cumulative size of 528.28±29.22nm and an alternative change in zeta potential. Differential scanning calorimetry (DSC) and transmission electron microscopy (TEM) revealed that the multilayered liposomes formed a spherical polyelectrolyte complex (PEC) after deposition. Observations in size distribution after 1 week found that the particles coated with even layers of polyelectrolytes, hyaluronate and chitosan (HA-CH), were more stable than the odd layers. Membrane stability in the presence of the surfactant Triton X-100 increased with an increase in bilayers as compared to uncoated liposomes. An increase in the number of bilayers deposited on the liposomal surface resulted in a sustained release of quercetin, with release kinetics that fit the Korsmeyer-Peppas model. In an in vitro skin permeation study, negatively charged (HA-CH)-L and positively charged CH-L were observed to have similar skin permeability, which were superior to uncoated liposomes. These results indicate that multilayered liposomes properly coated with polyelectrolytes of HA and CH by electrostatic interaction improve stability and can also function as potential drug delivery system for the transdermal delivery of the hydrophobic antioxidant quercetin.

Changes in Quality Characteristics of Pork Patties Containing Multilayered Fish Oil Emulsion during Refrigerated Storage

This study was performed to determine the effect of multilayered fish oil (FO) emulsion without or with trans-cinnamaldehyde on pork patties. Multilayered FO (-primary, -secondary, -tertiary) emulsions were prepared using a layer-by-layer deposition technique with Tween 20, chitosan, and low methoxyl pectin, and were added to pork patties at the same concentration. Pork patties were then stored for 20 d in a refrigerator (5℃) to study changes in quality. The results showed that the pH value of all samples significantly decreased but cooking loss increased during storage (p<0.05). However, water-holding capacity and moisture content showed no remarkable difference between treatments and storage periods (p>0.05). All pork patties containing multilayered FO (treated samples) showed higher values for lightness and significantly lower values for yellowness compared to control pork patties (untreated sample). Lipid oxidation was higher in treated pork patties than in control pork patties during storage. In addition, lipid oxidation and total viable bacterial count in pork patties decreased as the number of coating layers increased. However, hardness, cohesiveness, and springiness of all samples showed no significant change during storage (p>0.05) as compared to fresh pork patties. Furthermore, these did not remarkable change with addition of trans-cinnamaldehyde in all pork patties. From our results, we suggest that FO emulsion did not affect the texture characteristics of fresh pork patties, indicating that it could be used to improve the quality of pork patties by contributing high-quality fat such as unsaturated fatty acids.