Heparin-mediated PCR interference in SARS-CoV-2 assays and subsequent reversal with heparinase I

Heparin is postulated to block the interaction of SARS-CoV-2 with highly glycosylated proteins which are critical for binding the angiotensin-converting enzyme 2 (ACE2), an essential mechanism for host-cell entry and viral replication. Intranasal heparin is under investigation for use as a SARS-CoV-2 preventative in the IntraNasal Heparin Trial (INHERIT, NCT05204550). Heparin directly interferes with real-time quantitative polymerase chain reaction (RT-qPCR), the gold standard for SARS-CoV-2 detection. This study aimed to investigate the magnitude of heparin interference across various clinical laboratory testing platforms, and the reversal of any interference by degradation of heparin using the heparinase I enzyme in nasopharyngeal swab (NP) samples for SARS-CoV-2 analysis by RT-qPCR. Heparin-mediated PCR interference was evident at heparin concentrations as low as 10 IU/mL across all platforms tested, with the exclusion of the Hologic Panther Aptima SARS-CoV-2 assay. Rates of false negative or invalid results increased with increasing heparin concentrations on all platforms, except the Hologic Panther Aptima and Roche Cobas LIAT. Heparinase I reversed heparin-mediated PCR inhibition across in all samples tested, except those with initial Ct values >35. Our study shows that the use of heparin-containing nasal sprays interferes with the detection of SARS-CoV-2 in NP swab samples by RT-qPCR, a phenomenon that is not well recognised in the literature. Furthermore, this study has also demonstrated that heparin-mediated PCR inhibition can be prevented through heparinase I treatment, demonstrating restoration of clinically significant results with Ct values <35.

Dual centrifugation as a novel and efficient method for the preparation of lipodisks

Polyethylene glycol (PEG)-stabilized lipodisks have emerged as innovatiive, promising nanocarriers for several classes of drugs. Prior research underscores the important role of lipid composition and preparation method in determining the lipodisk size, uniformity, and drug loading capacity. In this study, we investigate dual centrifugation (DC) as a novel technique for the production of PEG-stabilized lipodisks. Moreover, we explore the potential use of DC for the encapsulation of two model drugs, curcumin and doxorubicin, within the disks. Our results show that by a considerate choice of experimental conditions, DC can be used as a fast and straightforward means to produce small and homogenous lipodisks with a hydrodynamic diameter of 20-30 nm. Noteworthy, the technique works well for the production of both cholesterol-free and cholesterol-containing disks and does not require pre-mixing of the lipids in organic solvent. Furthermore, our investigations confirm the efficacy of DC in formulating curcumin and doxorubicin within these lipodisks. For doxorubicin, careful control and optimization of the experimental conditions resulted in formulations displaying an encouraging encapsulation efficiency of 84 % and a favourable drug-to-lipid ratio of 0.13 in the disks.

Investigation of supramolecular structures in various aqueous solutions of an amyloid forming peptide using small-angle X-ray scattering

Aggregation of peptide molecules into amyloid fibrils is a characteristic feature of several degenerative diseases. However, the details behind amyloid-formation, and other self-assembled peptide aggregates, remain poorly understood. In this study, we have used small-angle X-ray scattering (SAXS), static and dynamic light scattering (SLS and DLS) as well as cryogenic transmission electron microscopy (cryo-TEM) to determine the structural geometry of self-assembled peptide aggregates in various dilute aqueous solutions. Pramlintide was used as a model peptide to assess the aggregation behaviour of an amyloid-forming peptide. The effects of adding sodium chloride (NaCl), sodium thiocyanate (NaSCN), and sodium fluoride (NaF) and the co-solvent dimethyl sulfoxide (DMSO) on the aggregation behaviour were studied. Our scattering data analysis demonstrates that small oligomeric fibrils aggregate to form networks of supramolecular assemblies with fractal dimensions. The choice of anion in small amounts of added salt has a significant impact on the size of the fibrils as well as on the fractal dimensions of supramolecular clusters. In DMSO the fractal dimension decreased with increasing DMSO concentration, indicating the formation of a less compact structure of the supramolecular assemblies.

A closer look at calcium-induced interactions between phosphatidylserine-(PS) doped liposomes and the structural effects caused by inclusion of gangliosides or polyethylene glycol- (PEG) modified lipids

The effects of polyethylene glycol- (PEG) modified lipids and gangliosides on the Ca2+ induced interaction between liposomes composed of palmitoyl-oleoyl phosphatidylethanolamine (POPE) and palmitoyl-oleoyl phosphatidylserine (POPS) was investigated at physiological ionic strength. Förster resonance energy transfer (FRET) studies complemented with dynamic light scattering (DLS) and cryo-transmission electron microscopy (Cryo-EM) show that naked liposomes tend to adhere, rupture, and collapse on each other's surfaces upon addition of Ca2+, eventually resulting in the formation of large multilamellar aggregates and bilayer sheets. Noteworthy, the presence of gangliosides or PEGylated lipids does not prevent the adhesion-rupture process, but leads to the formation of small, long-lived bilayer fragments/disks. PEGylated lipids seem to be more effective than gangliosides at stabilizing these structures. Attractive interactions arising from ion correlation are proposed to be a driving force for the liposome-liposome adhesion and rupture processes. The results suggest that, in contrast with the conclusions drawn from previous solely FRET-based studies, direct liposome-liposome fusion is not the dominating process triggered by Ca2+ in the systems studied.

Vesicle-enriched secretomes alter bacterial competitive abilities and are drivers of evolution in microbial communities

Microbial membrane vesicles can carry compounds that inhibit bacterial growth, but how they impact the fitness of the vesicle-producing bacterial species and influence community dynamics remain unexplored questions. To address these questions, we examined the effect of vesicle-enriched secretomes (VESs) in different single-species and multi-species systems. Effects of VESs on single-species growth dynamics were determined for nine bacterial species belonging to four genera (Escherichia, Salmonella, Pseudomonas and Bacillus) in nutrient-rich and poor growth media. Results showed both species-specific and nutrient-dependent effects of the VESs on bacterial growth. The strongest antagonistic effects were observed for VES isolated from the natural isolates of E. coli, while those isolated from P. aeruginosa PA14 affected the highest number of species. We further demonstrated that these VESs altered the competitive abilities of the species involved in two-species (S. Typhimurium LT2 and S. arizonae) and three-species systems (E. coli, S. Typhimurium LT2 and B. subtilis). Finally, using experimental evolution we showed that different bacterial species could rapidly acquire mutations that abrogated the antagonistic effects of VESs. This study demonstrates how VESs can contribute in shaping microbial communities, both by increasing the competitive ability of a given bacterial species and as a driver of genetic adaptation.

Long-Term Outcomes of Multidisciplinary Radiation Oncology Equity and Inclusion Committee Programming at an Academic Health System

PURPOSE/OBJECTIVE(S)

Academic radiation oncology departments are increasingly implementing educational programs to promote diversity, equity, and inclusion, but data on their impact remains sparse. This study aimed to assess learning outcomes and perceived impact of the programming of a multidisciplinary radiation oncology equity and inclusion committee (EIC).

MATERIALS/METHODS

Since August 2020, a committee of radiation therapists (RTTs), physicians (MDs), nurses (RNs), and administrators (ADs) has led an alternate-monthly online EIC meeting open to all radiation oncology employees at one health system. Learning goals of EIC programming are (1) to understand disparities in healthcare practice and outcomes for marginalized populations, (2) to discuss current events relevant to marginalized groups, and (3) to identify and address personal bias. EIC has featured expert guest speakers, open discussion, cultural events, and individual storytelling. In February 2023, we conducted a department-wide survey evaluating participation in one or more EIC meetings. EIC participants also completed an evaluation focused on learning goal achievement and program strengths/weaknesses. Multiple choice responses and 5-point Likert scale survey items were descriptively analyzed; open responses were qualitatively coded and categorized into themes.

RESULTS

There were 84 survey respondents, corresponding to a department response rate of 53%. Of these, 37 (44%) indicated participation in at least one EIC meeting. Participants were 35% RTTs, 16% MDs, 14% ADs, 3% physicists/dosimetrists, 3% RNs, and 19% undisclosed profession; 46% identified as a racial, ethnic, sexual, and/or gender minority. 41% of participants attended 5 or more sessions. Participants reported high overall value of the EIC meeting (mean value 3.7 / 5, SD 1.2) and 89% would recommend participation. There was strong agreement with achievement of EIC learning goals (mean agreement [MA] 3.9 / 5, SD 0.91), and most participants reported improved capability to understand (61%, MA 3.72 / 5, SD 0.99) and address (61%, MA 3.75 / 5, SD 0.83) the specific needs of their patients from marginalized groups. The three most common themes of EIC strengths were educational value, speaker quality, and improved work relationships. Commonly requested improvements included more practice scenarios, increasing participation, and giving more equitable attention to all minority groups. Among EIC non-participants, 75% reported non-participation due to scheduling, 71% felt that having an EIC was valuable, and 59% reported a desire to attend an EIC meeting in the future.

CONCLUSION

Nearly 3 years since implementation, EIC programming is highly valued. The majority of participants report achievement of learning goals and perceive self-improvement in care for marginalized groups as a result of participation. Further research is needed to externally validate the impact of this programming on learning and patient care domains.

Spontaneous Formation of Ultrasmall Unilamellar Vesicles in Mixtures of an Amphiphilic Drug and a Phospholipid

We have observed ultrasmall unilamellar vesicles, with diameters of less than 20 nm, in mixtures of the tricyclic antidepressant drug amitriptyline hydrochloride (AMT) and the unsaturated zwitterionic phospholipid 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) in physiological saline solution. The size and shape of spontaneously formed self-assembled aggregates have been characterized using complementary techniques, i.e., small-angle neutron and X-ray scattering (SANS and SAXS) and cryo-transmission electron microscopy (cryo-TEM). We observe rodlike mixed micelles in more concentrated samples that grow considerably in length upon dilution, and a transition from micelles to vesicles is observed as the concentration approaches the critical micelle concentration of AMT. Unlike the micelles, the spontaneously formed vesicles decrease in size with each step of dilution, and ultrasmall unilamellar vesicles, with diameters as small as about 15 nm, were observed at the lowest concentrations. The spontaneously formed ultrasmall unilamellar vesicles maintain their size for as long we have investigated them (i.e., several months). To the best of our knowledge, such small vesicles have never before been reported to form spontaneously in a biocompatible phospholipid-based system. Most interestingly, the size of the vesicles was observed to be strongly dependent on the chemical structure of the phospholipid, and in mixtures of AMT and the phospholipid 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC), the vesicles were observed to be considerably larger in size. The self-assembly behavior in the phospholipid-drug surfactant system in many ways resembles the formation of equilibrium micelles and vesicles in mixed anionic/cationic surfactant systems.

Tailoring the Lamellarity of Liposomes Prepared by Dual Centrifugation

Dual centrifugation (DC) is a new and versatile technique for the preparation of liposomes by in-vial homogenization of lipid-water mixtures. Size, size distribution, and entrapping efficiencies are strongly dependent on the lipid concentration during DC-homogenization. In this study, we investigated the detailed structure of DC-made liposomes. To do so, an assay to determine the ratio of inner to total membrane surfaces of liposomes (inaccessible surface) was developed based on either time-resolved or steady-state fluorescence spectroscopy. In addition, cryogenic electron microscopy (cryo-EM) was used to confirm the lamellarity results and learn more about liposome morphology. One striking result leads to the possibility of producing a novel type of liposome-small multilamellar vesicles (SMVs) with low PDI, sizes of the order of 100 nm, and almost completely filled with bilayers. A second particularly important finding is that VPGs can be prepared to contain open bilayer structures that will close spontaneously when, after storage, more aqueous phase is added and liposomes are formed. Through this process, a drug can effectively be entrapped immediately before application. In addition, dual centrifugation at lower lipid concentrations is found to produce predominantly unilamellar vesicles.

Excited-state and charge-carrier dynamics in binary conjugated polymer dots towards efficient photocatalytic hydrogen evolution

Aqueous dispersed conjugated polymer dots (Pdots) have shown promising application in photocatalytic hydrogen evolution. To efficiently extract photogenerated charges from type-II heterojunction Pdots for hydrogen evolution, the mechanistic study of photophysical processes is essential for Pdot optimization. Within this work, we use a PFODTBT donor (D) polymer and an ITIC small molecule acceptor (A) as a donor/acceptor (D/A) model system to study their excited states and charge/energy transfer dynamics via steady-state and time-resolved photoluminescence spectroscopy, respectively. Charge-carrier generation and the recombination dynamics of binary Pdots with different D/A ratios were followed using femtosecond transient absorption spectroscopy. A significant spectral relaxation of photoluminescence was observed for individual D Pdots, implying an energetic disorder by nature. However, this was not seen for charge carriers in binary Pdots, probably due to the ultrafast charge generation process at an early time (<200 fs). The results showed slower charge recombination upon increasing the ratio of ITIC in binary Pdots, which further resulted in an enhanced photocatalytic hydrogen evolution, twice that as compared to individual D Pdots. Although binary Pdots prepared via the nanoprecipitation method exhibit a large interfacial area that allows high charge generation efficiencies, it also provides a high possibility for charge recombination and limits the further utilization of free charges. Therefore, for the future design of type-II heterojunction Pdots, suppressing the charge carrier recombination via increasing the crystallinity and proper phase segregation is necessary for enhanced photocatalytic hydrogen evolution.

Polymer Dots as Photoactive Membrane Vesicles for [FeFe]-Hydrogenase Self-Assembly and Solar-Driven Hydrogen Evolution

A semiartificial photosynthesis approach that utilizes enzymes for solar fuel production relies on efficient photosensitizers that should match the enzyme activity and enable long-term stability. Polymer dots (Pdots) are biocompatible photosensitizers that are stable at pH 7 and have a readily modifiable surface morphology. Therefore, Pdots can be considered potential photosensitizers to drive such enzyme-based systems for solar fuel formation. This work introduces and unveils in detail the interaction within the biohybrid assembly composed of binary Pdots and the HydA1 [FeFe]-hydrogenase from Chlamydomonas reinhardtii. The direct attachment of hydrogenase on the surface of toroid-shaped Pdots was confirmed by agarose gel electrophoresis, cryogenic transmission electron microscopy (Cryo-TEM), and cryogenic electron tomography (Cryo-ET). Ultrafast transient spectroscopic techniques were used to characterize photoinduced excitation and dissociation into charges within Pdots. The study reveals that implementation of a donor-acceptor architecture for heterojunction Pdots leads to efficient subpicosecond charge separation and thus enhances hydrogen evolution (88 460 μmol_H2·g_H2ase^-1·h^-1). Adsorption of [FeFe]-hydrogenase onto Pdots resulted in a stable biohybrid assembly, where hydrogen production persisted for days, reaching a TON of 37 500 ± 1290 in the presence of a redox mediator. This work represents an example of a homogeneous biohybrid system combining polymer nanoparticles and an enzyme. Detailed spectroscopic studies provide a mechanistic understanding of light harvesting, charge separation, and transport studied, which is essential for building semiartificial photosynthetic systems with efficiencies beyond natural and artificial systems.

Influence of Chain Length of Gradient and Block Copoly(2-oxazoline)s on Self-Assembly and Drug Encapsulation

Amphiphilic gradient copolymers represent a promising alternative to extensively used block copolymers due to their facile one-step synthesis by statistical copolymerization of monomers of different reactivity. Herein, an in-depth analysis is provided of micelles based on amphiphilic gradient poly(2-oxazoline)s with different chain lengths to evaluate their potential for micellar drug delivery systems and compare them to the analogous diblock copolymer micelles. Size, morphology, and stability of self-assembled nanoparticles, loading of hydrophobic drug curcumin, as well as cytotoxicities of the prepared nanoformulations are examined using copoly(2-oxazoline)s with varying chain lengths and comonomer ratios. In addition to several interesting differences between the two copolymer architecture classes, such as more compact self-assembled structures with faster exchange dynamics for the gradient copolymers, it is concluded that gradient copolymers provide stable curcumin nanoformulations with comparable drug loadings to block copolymer systems and benefit from more straightforward copolymer synthesis. The study demonstrates the potential of amphiphilic gradient copolymers as a versatile platform for the synthesis of new polymer therapeutics.

Structural Characterization Study of a Lipid Nanocapsule Formulation Intended for Drug Delivery Applications Using Small-Angle Scattering Techniques

Lipid nanocapsules (LNCs) are increasingly being used for various drug delivery applications due to their versatile nature and ability to carry a wide variety of therapeutic drug molecules. In the present investigation, small-angle X-ray (SAXS) and neutron scattering (SANS) techniques were used to elucidate the structure of LNCs. Overall, size measurements obtained from SAXS and SANS techniques were complemented with dynamic light scattering, zeta potential, and cryogenic transmission electron microscopy measurements. The structural aspects of LNCs can be affected by drug loading and the properties of the drug. Here, the impact of drug loading on the overall structure was evaluated using DF003 as a model drug molecule. LNCs with varying compositions were prepared using a phase inversion method. Combined analysis of SAXS and SANS measurements indicated the presence of a core–shell structure in the LNCs. Further, the drug loading did not alter the overall core–shell structure of the LNCs. SANS data revealed that the core size remained unchanged with a radius of 20.0 ± 0.9 nm for unloaded LNCs and 20.2 ± 0.6 nm for drug-loaded LNCs. Furthermore, interestingly, the shell becomes thicker in an order of ∼1 nm in presence of the drug compared to the shell thickness of unloaded LNCs as demonstrated by SAXS data. This can be correlated with the strong association of hydrophilic DF003 with Kolliphor HS 15, a polyethylene glycol-based surfactant that predominantly makes up the shell, resulting in a drug-rich hydrated shell.

Influences on the dietary intakes of preschool children: a systematic scoping review

Background

Better diet quality of preschool children is associated with many important health outcomes, but there is significant room for improvement in many children’s dietary intakes. The determinants of children’s dietary intakes are complex and whole systems approaches may be effective tools for changing dietary intake. Collation of all the evidence available on determinants of preschool children’s dietary intake is necessary to ‘map’ the whole system of influence. Therefore, this systematic scoping review of available literature on determinants of dietary intakes in preschool children was undertaken.

Methods

The Joanna Briggs Institute methods for conducting a systematic scoping review were followed. Articles published since 2000 which assessed influences on the dietary intakes of preschool children were identified, yielding a total of 246 papers. Studies of children with clinical conditions (excluding obesity), or those conducted in middle and low-income countries were excluded, due to the different systems of influence in these populations. Data were extracted and information synthesised based on ecological level (child, parent, household, childcare, or wider determinants).

Results

Most articles focused on influences at the parental level (n = 118, 48%), followed by those at the child level (n = 73, 30%). Most of the studies were of cross-sectional design (n = 109, 44%). Whilst many studies considered influences at multiple ecological levels (n = 63, 26%) few analyses determined interactions between factors in their relationship with children’s dietary intakes, which is needed going forward using systems methods.

Conclusion

A wealth of evidence exists examining influences on the dietary intakes of preschool children and this information would benefit from analysis using a systems thinking approach in order to assess effective levers for intervention and what works, for whom, under what circumstances.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12966-022-01254-8.

Validation of the Kinetik Blood Pressure Monitor-Series 1 for use in adults at home and in clinical settings, according to the 2002 European Society of Hypertension International Protocol on the validation of blood pressure devices

The aim of this study was to assess the blood pressure (BP) measurement accuracy of the Kinetik Blood Pressure Monitor-Series 1 (BPM-1) for use in home or clinical settings according to the 2002 European Society of Hypertension International Protocol (ESH-IP). Forty-two participants were recruited to fulfil the required number of systolic and diastolic BP measurements according to the ESH-IP. Nine sequential same-arm BP readings were measured and analysed for each participant using the test device and observer mercury standard readings according to the 2002 ESH-IP. Forty one participants were used to obtain 33 sets of systolic and diastolic BP readings and were included in the analysis. Mean difference between the device measurements and the observer (mercury standard) measurements was 1.1 ± 7.2/1.1 ± 6.8 mmHg (mean ± standard deviation; systolic/diastolic). The number of systolic BP differences between the test and observer measurements that fell within 5, 10 and 15 mmHg was 65, 86 and 92. For diastolic readings, the number of test-observer measurement differences within 5, 10 and 15 mmHg was 77, 91 and 94. The number of participants with at least two out of three differences within 5 mmHg was 28 for systolic and 40 for diastolic BP readings. Three participants had no differences between the test and observer measurements within 5 mmHg in both the systolic and diastolic measurement categories. The Kinetik BPM-1 device fulfilled the requirements of the ESH-IP validation procedure and can be recommended for clinical use and self-measurement within the home.

Investigation of the enhanced ability of bile salt surfactants to solubilize phospholipid bilayers and form mixed micelles

The self-assembly in mixtures of the anionic bile salt surfactant sodium deoxycholate (NaDC) and the zwitterionic phospholipid 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) in physiological saline solution has been investigated using light scattering, small-angle X-ray scattering and cryo-transmission electron microscopy. Rather small tri-axial ellipsoidal NaDC-DMPC mixed micelles form at a high content of bile salt in the mixture, which increase in size as an increasing amount of DMPC is incorporated into the micelles. Eventually, the micelles begin to grow substantially in length to form long wormlike micelles. At higher mole fractions of DMPC, the samples become turbid and cryo-TEM measurements reveal the existence of large perforated vesicles (stomatosomes), coexisting with geometrically open disks. To our knowledge, stomatosomes have not been observed before for any bile salt-phospholipid system. Mixed micelles are found to be the sole aggregate structure in a very wide regime of bile salt-phospholipid compositions, i.e. up to about 77 mol% phospholipid in the micelles. This is much higher than the corresponding value of 25 mol% observed for the conventional surfactant hexadecyltrimethylammonium bromide (CTAB) mixed with DMPC in the same solvent. The enhanced ability of bile salt surfactants to solubilize phospholipid bilayers and form mixed micelles is rationalized using bending elasticity theory. From our theoretical analysis, we are able to conclude that amphiphilic molecules rank in the following order of increasing spontaneous curvature: phospholipids < conventional surfactants < bile salts. The bending rigidity of the different amphiphilic molecules increases according to the following sequence: bile salts < conventional surfactants < phospholipids.

Avoiding artifacts in liposome leakage measurements via cuvette- and liposome-surface modifications

The barrier properties of lipid membranes are often determined by investigating their solute permeability with the help of spectroscopic methods and the use of liposome-encapsulated self-quenching fluorescent dyes, for example, Carboxyfluorescein (CF). It was shown previously that liposome-surface interactions, and thus the choice of cuvette material, influence the result of such spectroscopic permeability/leakage experiments. In this work, we explore different methods to minimize the artifacts observed in spontaneous leakage measurements performed with cholesterol-containing liposomes. The spontaneous leakage of CF from liposomes with different composition and surface properties is monitored in cuvettes composed of quartz, polystyrene (PS), and Poly(methyl methacrylate) (PMMA). Our results show that significantly different leakage profiles are recorded for the exact same liposome batch depending on the cuvette material used. Quartz Crystal Microbalance with Dissipation Monitoring (QCM-D) experiments indicate that these discrepancies likely arise from side processes occurring at the solution-cuvette interface, mainly, the attaching and spreading of liposomes. Further, we show that in some cases it is possible to minimize liposome-cuvette interactions, and reduce the experimental artifacts, by supplementing the liposomes with polyethylene glycol (PEG)-grafted lipids or gangliosides, and/or by pre-adsorbing free PEG to the cuvette walls. The collected data suggest that quartz cuvettes modified by adsorption of PEG8000 are suitable for spontaneous leakage experiments with POPC:cholesterol-based liposomes, while other cuvette materials perform poorly in the same experiments.

Formulation development and upscaling of lipid nanocapsules as a drug delivery system for a novel cyclic GMP analogue intended for retinal drug delivery

Lipid nanocapsules (LNCs) were prepared with a novel cyclic GMP analogue, DF003, intended for the treatment of neurodegenerative retinal degenerations. LNCs loaded with DF003 were prepared by a phase inversion method and characterized for particle size, polydispersity index, drug loading, entrapment efficiency, stability, and in vitro drug release. Particle size, PdI and zeta potential of selected optimized formulation were 76 ± 1.2 nm, 0.16 ± 0.02, and -11.6 ± 0.4 mV, respectively, with an entrapment efficiency of 69 ± 0.5%. The selected formulation showed a sustained drug release for up to 6 days in phosphate buffer as well as in vitreous components. Stability evaluation of LNCs in presence of vitreous components demonstrated structural stability and compatibility. Further, the nanoparticle preparation process was upscaled to 1000 times (10 L) of the typical lab scale (0.01 L). Product parameters were observed to be unaffected by the upscaling, demonstrating that the LNCs were of the same quality as those prepared at lab scale. Additionally, the manufacturing process was adapted and assessed for a continuous production of LNCs to leverage it for industrial viability. Overall, these findings reveal the remarkable potential of LNCs as drug delivery vehicles and their possibility for clinical translation.

Panchromatic Ternary Polymer Dots Involving Sub-Picosecond Energy and Charge Transfer for Efficient and Stable Photocatalytic Hydrogen Evolution

Panchromatic ternary polymer dots (Pdots) consisting of two conjugated polymers (PFBT and PFODTBT) based on fluorene and benzothiadiazole groups, and one small molecular acceptor (ITIC) have been prepared and assessed for photocatalytic hydrogen production with the assistance of a Pt cocatalyst. Femtosecond transient absorption spectroscopic studies of the ternary Pdots have revealed both energy and charge transfer processes that occur on the time scale of sub-picosecond between the different components. They result in photogenerated electrons being located mainly at ITIC, which acts as both electron and energy acceptor. Results from cryo-transmission electron microscopy suggest that ITIC forms crystalline phases in the ternary Pdots, facilitating electron transfer from ITIC to the Pt cocatalyst and promoting the final photocatalytic reaction yield. Enhanced light absorption, efficient charge separation, and the ideal morphology of the ternary Pdots have rendered an external quantum efficiency up to 7% at 600 nm. Moreover, the system has shown a high stability over 120 h without obvious degradation of the photocatalysts.

Nanomicelles potentiate histone deacetylase inhibitor efficacy in vitro

Background

Amphiphilic block copolymers used as nanomicelle drug carriers can effectively overcome poor drug solubility and specificity issues. Hence, these platforms have a broad applicability in cancer treatment. In this study, Pluronic F127 was used to fabricate nanomicelles containing the histone deacetylase inhibitor SAHA, which has an epigenetic-driven anti-cancer effect in several tumor types. SAHA-loaded nanomicelles were prepared using a thin-film drying method and characterized for size, surface charge, drug content, and drug release properties. Loaded particles were tested for in vitro activity and their effect on cell cycle and markers of cancer progression.

Results

Following detailed particle characterization, cell proliferation experiments demonstrated that SAHA-loaded nanomicelles more effectively inhibited the growth of HeLa and MCF-7 cell lines compared with free drug formulations. The 30 nm SAHA containing nanoparticles were able to release up to 100% of the encapsulated drug over a 72 h time window. Moreover, gene and protein expression analyses suggested that their cytoreductive effect was achieved through the regulation of p21 and p53 expression. SAHA was also shown to up-regulate E-cadherin expression, potentially influencing tumor migration.

Conclusions

This study highlights the opportunity to exploit pluronic-based nanomicelles for the delivery of compounds that regulate epigenetic processes, thus inhibiting cancer development and progression.

0024 PTSD with Concurrent Excessive Daytime Sleepiness Alters Gene Expression in Military Personnel and Veterans; An RNA-Sequencing Study

Introduction

Up to 91% of military personnel and veterans with posttraumatic stress disorder (PTSD) report co-occurring sleep disturbances, including. insomnia and excessive daytime sleepiness (EDS). Sleep disturbances have been shown not only to increase the risk of developing PTSD, but to exacerbate and maintain PTSD symptomology. The aim of this study was to examine gene expression in active duty military personnel and veterans with PTSD, with and without EDS. Participants were categorized into three groups; 1) PTSD with EDS (PTSDwEDS; n=21), 2) PTSD without EDS (PTSDnoEDS; n=25), or 3) Controls (no PTSD and no EDS; n=57).

Methods

Participants were 79% male, mean age of 37.6years (SD=11.2years). PTSD symptoms were measured using the PTSD checklist for civilians (PCL-C); participants were classified as PTSD-present using DSM-IV-TR criteria of “moderate-to-severe”. Daytime sleepiness was assessed using the Epworth Sleepiness Scale (ESS), high sleepiness was indicated by an ESS score &gt;13. We performed RNA-seq with Illumina’s HiSeq 2500 in paired-end. We conducted quality control using FastQC and aligned to GRCh38 reference genome using STAR (v2.5.3a). Differentially expressed genes identified using DESeq2 (v1.20.0) with False Discovery Rate of 0.10. Finally, Ingenuity Pathway Analysis (IPA) was conducted to identify dysregulated gene networks.

Results

Between the Controls and PTSDnoEDS groups, two genes were significantly dysregulated. In controls and PTSDwEDS groups, 251 genes were dysregulated. The IPA networks showed that genes associated with inflammation were significantly dysregulated. Finally, between PTSDwEDS and PTSDnoEDS there were 1,873 significantly dysregulated genes. The IPA networks identified dysregulation of genes related to sleep, fatigue, circadian, and mitochondrial function.

Conclusion

Taken together this data indicates that EDS that is co-morbidly experienced with PTSD is associated with significant gene dysregulation, above and beyond that observed in participants with PTSD without significant EDS and controls. Treating EDS in military personnel and veterans with PTSD is important.

Support

This work was supported by the Center for Neuroscience and Regenerative Medicine (CNRM)

Tumor-Targeted Delivery of the p53-Activating Peptide VIP116 with PEG-Stabilized Lipodisks

Stapled peptides targeting the interaction between p53 and its negative regulators MDM2 and MDM4 have exhibited great potential as anti-cancer drugs, albeit with room for improvement in formulation and tumor specificity. Lipid bilayer disks (lipodisks) have emerged as promising drug nanocarriers and can by attachment of targeting moieties be directed selectively towards tumor cells. Tumor-targeted delivery of stapled peptides by use of lipodisks may therefore increase the uptake in the tumors and limit toxicity in healthy tissue. Here, we utilized epidermal growth factor receptor (EGFR)-targeted lipodisks to deliver p53-activating stapled peptide VIP116 to EGFR-expressing tumor cells. We demonstrate that VIP116 can be stably formulated in lipodisks (maximum peptide/lipid molar ratio 0.11). In vitro cell studies verify specific binding of EGF-decorated lipodisks to tumor cells and confirm that targeted delivery of VIP116 significantly decreases tumor cell viability.

Gel Phase 1,2-Distearoyl-sn-glycero-3-phosphocholine-Based Liposomes Are Superior to Fluid Phase Liposomes at Augmenting Both Antigen Presentation on Major Histocompatibility Complex Class II and Costimulatory Molecule Display by Dendritic Cells in Vitro

Lipid-based nanoparticles have in recent years attracted increasing attention as pharmaceutical carriers. In particular, reports of them having inherent adjuvant properties combined with their ability to protect antigen from degradation make them suitable as vaccine vectors. However, the physicochemical profile of an ideal nanoparticle for vaccine delivery is still poorly defined. Here, we used an in vitro dendritic cell assay to assess the immunogenicity of a variety of liposome formulations as vaccine carriers and adjuvants. Using flow cytometry, we investigated liposome-assisted antigen presentation as well as the expression of relevant costimulatory molecules on the cell surface. Cytokine secretion was further evaluated with an enzyme-linked immunosorbent assay (ELISA). We show that liposomes can successfully enhance antigen presentation and maturation of dendritic cells, as compared to vaccine fusion protein (CTA1-3Eα-DD) administered alone. In particular, the lipid phase state of the membrane was found to greatly influence the vaccine antigen processing by dendritic cells. As compared to their fluid phase counterparts, gel phase liposomes were more efficient at improving antigen presentation. They were also superior at upregulating the costimulatory molecules CD80 and CD86 as well as increasing the release of the cytokines IL-6 and IL-1β. Taken together, we demonstrate that gel phase liposomes, while nonimmunogenic on their own, significantly enhance the antigen-presenting ability of dendritic cells and appear to be a promising way forward to improve vaccine immunogenicity.

Latent autoimmune diabetes of adulthood (LADA) is associated with small fibre neuropathy

AIM

To assess if latent autoimmune diabetes of adulthood (LADA) is associated with small fibre neuropathy.

METHODS

Participants with LADA (n=31), Type 2 diabetes (n=31) and healthy control participants without diabetes (n=31) underwent a detailed assessment of neurologic deficits, quantitative sensory testing, electrophysiology, skin biopsy and corneal confocal microscopy.

RESULTS

The groups were matched for age (healthy control without diabetes: 53.5±9.1 vs. Type 2 diabetes: 58.0±6.5 vs. LADA: 53.2±11.6 years), duration of diabetes (Type 2 diabetes: 10.0±8.3 vs. LADA: 11.0±9.1 years) and blood pressure. However, BMI (P=0.01) and triglycerides (P=0.0008) were lower and HbA_1c (P=0.0005), total cholesterol (P=0.01) and HDL (P=0.002) were higher in participants with LADA compared with Type 2 diabetes. Peroneal motor nerve conduction velocity (P=0.04) and sural sensory nerve conduction velocity (P=0.008) were lower in participants with latent autoimmune diabetes in adults compared with Type 2 diabetes. Intra-epidermal nerve fibre density (P=0.008), corneal nerve fibre density (P=0.003) and corneal nerve branch density (P=0.006) were significantly lower in participants with LADA compared with Type 2 diabetes. There were no significant differences in the other neuropathy parameters.

CONCLUSIONS

Despite comparable age and duration of diabetes, participants with LADA demonstrate more severe neuropathy and particularly small fibre neuropathy, compared with participants with Type 2 diabetes.

A Type 1 Diabetes Genetic Risk Score Predicts Progression of Islet Autoimmunity and Development of Type 1 Diabetes in Individuals at Risk

OBJECTIVE

We tested the ability of a type 1 diabetes (T1D) genetic risk score (GRS) to predict progression of islet autoimmunity and T1D in at-risk individuals.

RESEARCH DESIGN AND METHODS

We studied the 1,244 TrialNet Pathway to Prevention study participants (T1D patients' relatives without diabetes and with one or more positive autoantibodies) who were genotyped with Illumina ImmunoChip (median [range] age at initial autoantibody determination 11.1 years [1.2-51.8], 48% male, 80.5% non-Hispanic white, median follow-up 5.4 years). Of 291 participants with a single positive autoantibody at screening, 157 converted to multiple autoantibody positivity and 55 developed diabetes. Of 953 participants with multiple positive autoantibodies at screening, 419 developed diabetes. We calculated the T1D GRS from 30 T1D-associated single nucleotide polymorphisms. We used multivariable Cox regression models, time-dependent receiver operating characteristic curves, and area under the curve (AUC) measures to evaluate prognostic utility of T1D GRS, age, sex, Diabetes Prevention Trial-Type 1 (DPT-1) Risk Score, positive autoantibody number or type, HLA DR3/DR4-DQ8 status, and race/ethnicity. We used recursive partitioning analyses to identify cut points in continuous variables.

RESULTS

Higher T1D GRS significantly increased the rate of progression to T1D adjusting for DPT-1 Risk Score, age, number of positive autoantibodies, sex, and ethnicity (hazard ratio [HR] 1.29 for a 0.05 increase, 95% CI 1.06-1.6; P = 0.011). Progression to T1D was best predicted by a combined model with GRS, number of positive autoantibodies, DPT-1 Risk Score, and age (7-year time-integrated AUC = 0.79, 5-year AUC = 0.73). Higher GRS was significantly associated with increased progression rate from single to multiple positive autoantibodies after adjusting for age, autoantibody type, ethnicity, and sex (HR 2.27 for GRS >0.295, 95% CI 1.47-3.51; P = 0.0002).

CONCLUSIONS

The T1D GRS independently predicts progression to T1D and improves prediction along T1D stages in autoantibody-positive relatives.

Effects of personal air pollution exposure on asthma symptoms, lung function and airway inflammation

BACKGROUND

There is evidence that air pollution increases the risk of asthma hospitalizations and healthcare utilization, but the effects on day-to-day asthma control are not fully understood.

OBJECTIVE

We undertook a prospective single-centre panel study to test the hypothesis that personal air pollution exposure is associated with asthma symptoms, lung function and airway inflammation.

METHODS

Thirty-two patients with a clinical diagnosis of asthma were provided with a personal air pollution monitor (Cairclip NO₂ /O₃ ) which was kept on or around their person throughout the 12-week follow-up period. Ambient levels of NO₂ and particulate matter were modelled based upon satellite imaging data. Directly measured ozone, NO₂ and particulate matter levels were obtained from a monitoring station in central Leicester. Participants made daily electronic records of asthma symptoms, peak expiratory flow and exhaled nitric oxide. Spirometry and asthma symptom questionnaires were completed at fortnightly study visits. Data were analysed using linear mixed effects models and cross-correlation.

RESULTS

Cairclip exposure data were of good quality with clear evidence of diurnal variability and a missing data rate of approximately 20%. We were unable to detect consistent relationships between personal air pollution exposure and clinical outcomes in the group as a whole. In an exploratory subgroup analysis, total oxidant exposure was associated with increased daytime symptoms in women but not men.

CONCLUSIONS AND CLINICAL RELEVANCE

We did not find compelling evidence that air pollution exposure impacts on day-to-day clinical control in an unselected asthma population, but further studies are required in larger populations with higher exposure levels. Women may be more susceptible than men to the effects of air pollution, an observation which requires confirmation in future studies.

Freeze-dried and re-hydrated liquid crystalline nanoparticles stabilized with disaccharides for drug-delivery of the plectasin derivative AP114 antimicrobial peptide

Liquid crystalline nanoparticles (LCNPs), e.g. cubosomes and hexosomes, are receiving more and more attraction as drug delivery vehicles. Dry powder formulation that forms LCNPs upon hydration can be advantageous to make new routes of administration accessible. In this work, we investigate use of three disaccharides (lactose, trehalose and sucrose) as protective matrices for glycerol monooleate based LCNP forming powders produced by freeze-drying. Phase behavior, particle size and size distributions at the different preparation steps were monitored by small angle x-ray scattering (SAXS) and dynamic light scattering (DLS). Particle appearance was imaged by cryogenic transmission electron microscopy (cryo-TEM). Moreover, the therapeutic relevant antimicrobial peptide AP114 (plectasin derivative) was incorporated in the formulations. Peptide encapsulation and release as well as in vitro antibacterial effect were investigated. Results showed that all freeze-dried powders did form particles with liquid crystalline structure upon hydration. However, a phase transition from the bicontinuous cubic Pn3m to the reversed hexagonal was observed, as a consequence of sugar addition and the freeze-drying procedure. Data indicates that trehalose is the preferred choice of lyo-protectant in order to maintain a mono-modal particle size distribution. In addition, antimicrobial activity of AP114-containing formulations was found to be highest for the formulation containing trehalose. The release kinetics of AP114 from the nanoparticles was strongly affected by the dimensions of the hexagonal phase. Larger dimension of the hexagonal phase, significantly improved the release of AP114 and antimicrobial activity of the formulation.

Better arthritis care: Patients' expectations and priorities, the competencies that community-based health professionals need to improve their care of people with arthritis?

OBJECTIVE

The aim of the present study was to identify the competencies that patients think non-specialist community-based nurses and allied health professionals (AHPs) need to enable them to assess, care for and manage arthritis appropriately.

METHODS

Four face-to-face focus groups were held with a total of 16 women and nine men with arthritis, to discuss the care they received from community-based health professionals, the skills and knowledge they expected from community-based health professionals and what they prioritized.

RESULTS

People with arthritis wanted health providers to have an understanding of the difference between inflammatory arthritis (IA) and osteoarthritis (OA), of how serious OA can be, and of the unpredictability of IA and flares. They emphasized the need for nurses and AHPs to understand the psychosocial impact of arthritis on individuals, family and friends, and the psychological adjustment needed when diagnosed with IA. They wanted community-based health professionals to have some knowledge of the types of drug treatments that people with IA receive and the implications of taking immunosuppressive drugs. They also wanted them to understand the pain associated with arthritis, particularly OA, which participants felt was not taken seriously enough. They wanted nurses and AHPs in the community to be able to give basic advice on pacing and pain management, to make multidisciplinary referrals, to communicate effectively between referral points and to be able to signpost people to sources of help and good, reliable sources of education and information (especially for OA). They also wanted them to understand that patients who have had a diagnosis for a long time are the experts in their own disease. Other areas which were emphasized as being important were good communication skills and taking a holistic approach to caring for people with arthritis.

CONCLUSIONS

OA and IA differ significantly, both in their nature and their management. However, patients with arthritis want health professionals working in the community to be able to take a holistic approach to arthritis, with an understanding not just of the physical effects, but also their impact on the lives of patients, their family and their wider social circle, and on their ability to participate. People with OA want their condition to be taken seriously and to be offered appropriate management options, while people with IA want professionals to understand the unpredictability of their condition and to have a basic understanding of the drugs used for its treatment.

Effect of ubiquinone-10 on the stability of biomimetic membranes of relevance for the inner mitochondrial membrane

Ubiquinone-10 (Q10) plays a pivotal role as electron-carrier in the mitochondrial respiratory chain, and is also well known for its powerful antioxidant properties. Recent findings suggest moreover that Q10 could have an important membrane stabilizing function. In line with this, we showed in a previous study that Q10 decreases the permeability to carboxyfluorescein (CF) and increases the mechanical strength of 1-palmitoyl-2-oleyl-sn-glycero-phosphocholine (POPC) membranes. In the current study we report on the effects exerted by Q10 in membranes having a more complex lipid composition designed to mimic that of the inner mitochondrial membrane (IMM). Results from DPH fluorescence anisotropy and permeability measurements, as well as investigations probing the interaction of liposomes with silica surfaces, corroborate a membrane stabilizing effect of Q10 also in the IMM-mimicking membranes. Comparative investigations examining the effect of Q10 and the polyisoprenoid alcohol solanesol on the IMM model and on membranes composed of individual IMM components suggest, moreover, that Q10 improves the membrane barrier properties via different mechanisms depending on the lipid composition of the membrane. Thus, whereas Q10's inhibitory effect on CF release from pure POPC membranes appears to be directly and solely related to Q10's lipid ordering and condensing effect, a mechanism linked to Q10's ability to amplify intrinsic curvature elastic stress dominates in case of membranes containing high proportions of palmitoyl-2-oleoyl-sn-glycero-3-phosphoethanolamine (POPE).

Vaccines in pregnancy: The dual benefit for pregnant women and infants

Maternal immunization has the potential to reduce the burden of infectious diseases in the pregnant woman and her infant. Many countries now recommend immunization against influenza at any stage of pregnancy and against pertussis in the third trimester. Despite evidence of the safety and effectiveness of these vaccines when administered during pregnancy, uptake generally remains low for influenza and moderate for pertussis vaccine. Enhancing confidence in both immunization providers and pregnant women by increasing the evidence-base for the safety and effectiveness of vaccines during pregnancy, improving communication and access by incorporating immunization into standard models of antenatal care are likely to improve uptake. Developing a framework for implementation of vaccines for pregnant women which is cognizant of local and national cultural, epidemiological, behavioral and societal factors will enable a smooth transition and high uptake for new vaccines currently in development for pregnant women.

Better arthritis care: What training do community-based health professionals need to improve their care of people with arthritis? A Delphi study

OBJECTIVE

The aim of the present study was to identify the competencies that non-specialist community-based nurses and allied health professionals (AHPs) need to enable them to assess, care for and manage arthritis appropriately.

METHODS

A Delphi survey with an expert panel of 43 rheumatology specialists and expert patients was used to identify the competencies needed by community-based nurses and AHPs to enable them to improve their care of people with arthritis. The process was informed by feedback from focus groups with arthritis patients, community-based nurses and AHPs.

RESULTS

The core competencies in arthritis care needed by non-specialist community-based nurses and AHPs were identified. The key goals identified were to increase the understanding of arthritis and its impact on patients' lives, and to increase the ability to help patients to self-manage their condition and access support. Competencies included an understanding of the pathology underlying inflammatory and non-inflammatory arthritis, the ability to distinguish between the two and the ability to recognize early warning signs, with an emphasis on osteoarthritis (OA), rheumatoid arthritis, gout and septic arthritis. Essential competencies included the ability to engage in shared decision making, goal setting and signposting, to provide patients with education and information and to make appropriate referrals.

CONCLUSIONS

Health professionals working in the community commonly encounter arthritis as a presenting problem or as a co-morbidity. The quality of care provided to people with inflammatory arthritis and OA in the community is currently variable. The present study identified the core competencies that all community-based nurses and AHPs should have in relation to OA and inflammatory arthritis.

Cubosomes post-loaded with antimicrobial peptides: characterization, bactericidal effect and proteolytic stability

Novel antibiotics, such as antimicrobial peptides (AMPs), have recently attended more and more attraction. In this work, dispersed cubic liquid crystalline gel (cubosomes) was used as drug delivery vehicles for three AMPs (AP114, DPK-060 and LL-37). Association of peptides onto cubosomes was studied at two cubosome/peptide ratios using high performance liquid chromatography, ζ-potential and circular dichroism measurements. AMPs impact on the cubosome structure was investigated using small angle x-ray scattering and cryogenic transmission electron microscopy. The antimicrobial effect of the AMP loaded cubosomes was studied in vitro by minimum inhibitory concentration and time-kill assays. Proteolytic protection was investigated by incubating the formulations with two elastases and the antimicrobial effect after proteolysis was studied using radial diffusion assay. Different association efficacy onto the cubosomes was observed among the AMPs, with LL-37 showing greatest association (>60%). AP114 loaded cubosomes displayed a preserved antimicrobial effect, whereas for LL-37 the broad spectrum bacterial killing was reduced to only comprise Gram-negative bacteria. Interestingly, DPK-060 loaded cubosomes showed a slight enhanced effect against S. aureus and E. coli strains. Moreover, the cubosomes were found to protect LL-37 from proteolytic degradation, resulting in a significantly better bactericidal effect after being subjected to elastase, compared to unformulated peptide.

Distinct modulatory role of RNA in the aggregation of the tumor suppressor protein p53 core domain

Inactivation of the tumor suppressor protein p53 by mutagenesis, chemical modification, protein-protein interaction, or aggregation has been associated with different human cancers. Although DNA is the typical substrate of p53, numerous studies have reported p53 interactions with RNA. Here, we have examined the effects of RNA of varied sequence, length, and origin on the mechanism of aggregation of the core domain of p53 (p53C) using light scattering, intrinsic fluorescence, transmission electron microscopy, thioflavin-T binding, seeding, and immunoblot assays. Our results are the first to demonstrate that RNA can modulate the aggregation of p53C and full-length p53. We found bimodal behavior of RNA in p53C aggregation. A low RNA:protein ratio (∼1:50) facilitates the accumulation of large amorphous aggregates of p53C. By contrast, at a high RNA:protein ratio (≥1:8), the amorphous aggregation of p53C is clearly suppressed. Instead, amyloid p53C oligomers are formed that can act as seeds nucleating de novo aggregation of p53C. We propose that structured RNAs prevent p53C aggregation through surface interaction and play a significant role in the regulation of the tumor suppressor protein.

Myeloid-derived suppressor cell-like fibrocytes are increased and associated with preserved lung function in chronic obstructive pulmonary disease

BACKGROUND

The role of fibrocytes in chronic obstructive pulmonary disease (COPD) is unknown. We sought to enumerate blood and tissue fibrocytes in COPD and determine the association of blood fibrocytes with clinical features of disease.

METHODS

Utilizing flow cytometry to identify circulating, collagen type 1⁺ cells, we found two populations: (i) CD45⁺ CD34⁺ (fibrocytes) and (ii) CD45⁺ CD34^- [myeloid-derived suppressor cell (MDSC)-like fibrocytes] cells in stable COPD (n = 41) and control (n = 29) subjects. Lung resection material from a separate group of subjects with (n = 11) or without (n = 11) COPD was collected for tissue fibrocyte detection. We examined circulating fibrocyte populations for correlations with clinical parameters including quantitative computed tomography (qCT) and determined pathways of association between correlated variables using a path analysis model.

RESULTS

Blood and tissue fibrocytes were not increased compared to control subjects nor were blood fibrocytes associated with lung function or qCT, but were increased in eosinophilic COPD. Myeloid-derived suppressor cell-like fibrocytes were increased in COPD compared to controls [2.3 (1.1-4.9), P = 0.038]. Our path analysis model showed that collagen type 1 intensity for MDSC-like fibrocytes was positively associated with lung function through associations with air trapping, predominately in the upper lobes.

CONCLUSION

We have demonstrated that two circulating populations of fibrocyte exist in COPD, with distinct clinical associations, but are not prevalent in proximal or small airway tissue. Blood MDSC-like fibrocytes, however, are increased and associated with preserved lung function through a small airway-dependent mechanism in COPD.

A simple passive equilibration method for loading carboplatin into pre-formed liposomes incubated with ethanol as a temperature dependent permeability enhancer

A passive equilibration method which relies on addition of candidate drugs to pre-formed liposomes is described as an alternative method for preparing liposome encapsulated drugs. The method is simple, rapid and applicable to liposomes prepared with high (45mol%) or low (<20mol%) levels of cholesterol. Passive equilibration is performed in 4-steps: (i) formation of liposomes, (ii) addition of the candidate drug to the liposomes in combination with a permeability enhancing agent, (iii) incubation at a temperature that facilitates diffusion of the added compound across the lipid bilayer, and (iv) quenching the enhanced membrane permeability by reduction in temperature and/or removal of the permeabilization enhancer. The method is fully exemplified here using ethanol as the permeabilization enhancer and carboplatin (CBDCA) as the drug candidate. It is demonstrated that ethanol can be added to liposomes prepared with 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC) and Cholesterol (Chol) (55:45mol ratio) in amounts up to 30% (v/v) with no change in liposome size, even when incubated at temperatures>60°C. Super-saturated solutions of CBDCA (40mg/mL) can be prepared at 70°C and these are stable in the presence of ethanol even when the temperature is reduced to <30°C. maximum CBDCA encapsulation is achieved within 1h after the CBDCA solution is added to pre-formed DSPC/Chol liposomes in the presence of 30% (v/v) ethanol at 60°C. When the pre-formed liposomes are mixed with ethanol (30% v/v) at or below 40°C, the encapsulation efficiency is reduced by an order of magnitude. The method was also applied to liposomes prepared from other compositions include a cholesterol free formulations (containing 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[carboxy(polyethylene glycol)-2000] (DSPE-PEG₂₀₀₀)) and a low Chol (<20mol%) formulations prepared with the distearoyl-sn-glycero-3-phospho-(1'-rac-glycerol) DSPG)). The cytotoxic activity of CBDCA was unaffected when prepared in this manner and two of the resultant formulations exhibited good stability in vitro and in vivo. The cytotoxic activity of CBDCA was unaffected when prepared in this manner and the resultant formulations exhibited good stability in vitro and in vivo. Pharmacokinetics studies in CD-1 mice indicated that the resulting formulations increased the circulation half life of the associated CBDCA significantly (AUC_0-24h of CBDCA=0.016μg·hr/mL; AUC_0-24h of the DSPC/Chol CBDCA formulation=1014.0μg·hr/mL and AUC_0-24h of the DSPC/DSPG/Chol CBDCA formulation=583.96μg·hr/mL). Preliminary efficacy studies in Rag-2M mice with established subcutaneous H1975 and U-251 tumors suggest that the therapeutic activity of CBDCA is improved when administered in liposomal formulations. The encapsulation method described here has not been disclosed previously and will have broad applications to drugs that would normally be encapsulated during liposome manufacturing.

EGF-targeting lipodisks for specific delivery of poorly water-soluble anticancer agents to tumour cells

We report on the construction of tumour targeting PEG-stabilized lipodisks capable of receptor mediated intracellular delivery of curcumin.

Characterizing and Controlling the Loading and Release of Cationic Amphiphilic Peptides onto and from PEG-Stabilized Lipodisks

Recent studies have identified PEG-stabilized lipid nanodisks (lipodisks) as promising carriers for cationic amphiphilic peptides with antimicrobial and anticancer activity. Using fluorimetric and nanogravimetric methods, we have in this work characterized the parameters describing and controlling the binding of three selected peptides (melittin, LL37, and magainin 2) onto lipodisks. It was found that the affinity of melittin for lipodisks is independent of the disk size and rim charge. On the other hand, the number of binding sites is strongly dependent on both parameters, with the highest loading being obtained for small disks with a negatively charged rim. An optimized composition of the lipodisks was utilized to study the loading of antimicrobial peptides magainin 2 and human LL37. It was observed that although magainin 2 can be loaded in large amounts, it is released very fast upon dilution, which limits future therapeutic applications. In contrast, LL37 can be loaded at relevant concentrations and the formulation is stable. This opens up for applications of LL37-loaded lipodisks as antibiotics and in anticancer treatments.