Shar-Pei autoinflammatory disease with skin necrosis due to neutrophilic vasculitis: a case report.

A 4-month-old female Shar-pei dog was admitted with apathy, anorexia, and vomiting. The patient had an appropriate vaccination protocol, with the last vaccine administered 2.5 weeks prior to the onset of clinical signs. Physical examination revealed tachycardia, fever and swelling of the tibiotarsal joints. Several diagnostic tests including complete blood cell count, biochemistry profile, urinalysis, thoracic radiographs, hind limbs radiographs, abdominal ultrasound, and infectious diseases tests, were conducted to determine the underlying cause. Shar-Pei Auto-inflammatory Disease (SPAID) was diagnosed. Additionally, the patient developed skin necrosis in the inner aspect of the tibiotarsal joints as a complication. A skin biopsy revealed cutaneous vasculopathy causing degeneration, abrupt ulceration, and ischemic necrosis with intense neutrophilic inflammation of the dermis and subcutis. Moreover, a hospital-acquired infection was identified by skin culture. Debridement of the necrotic skin was performed, and due to its' severity and extent, the wound was closed by secondary intention. A diagnostic protocol and the therapeutic dose of acetylsalicylic acid, which led to clinical improvement, are recommended here. The patient has continued to present episodic manifestations of SPAID mainly fever and swelling of the tibiotarsal joints, but there has been no recurrence of necrosis or other cutaneous lesion in the last two years.

Nonviral Platform for Expression of Recombinant Protein in Insect Cells.

Nonviral transfection has been used to express various recombinant proteins, therapeutics, and virus-like particles (VLP) in mammalian and insect cells. Virus-free methods for protein expression require fewer steps for obtaining protein expression by eliminating virus amplification and measuring the infectivity of the virus. The nonviral method uses a nonlytic plasmid to transfect the gene of interest into the insect cells instead of using baculovirus, a lytic system. In this chapter, we describe one of the transfection methods, which uses polyethyleneimine (PEI) as a DNA delivery material into the insect cells to express the recombinant protein in both adherent and suspension cells.

Brow rhytidectomy with or without Stades-like procedure for correction of pseudoptosis and trichiasis-entropion of the upper eyelid in Chow Chow and Shar-Pei dogs: A retrospective study of 27 dogs (2019-2022).

PURPOSE: Heavy brows in Chow Chow and Shar-Pei dogs can be associated with pseudoptosis and trichiasis-entropion of the upper eyelids, causing vision impairment and ocular discomfort. This study describes the outcomes of brow rhytidectomy ± Stades-like procedure to address these anatomical abnormalities. METHODS: Retrospective medical records review (2019-2022). RESULTS: Twenty-seven dogs (n = 15 Chow Chow, n = 12 Shar-Peis) were included, aged 1.9 ± 1.5 years (0.5-6.5 years). Presenting complaints included recurrent episodes of ocular inflammation (n = 13, 48.1%), blepharospasm (n = 10, 37.0%), corneal ulcers (n = 8, 29.6%), entropion (n = 6, 22.2%), and impaired vision (n = 4, 14.8%). Brow skin was removed as follows: (i) First incision parallel and 10-15 mm dorsal to upper lid, slightly extending beyond medial/lateral canthi; (ii) second incision forming an arc with its apex 15-35 mm dorsal to the first incision; and (iii) standard two or three layers closure. In 22/27 dogs, a Stades-like procedure was performed by removing a 2-4 mm strip of skin above eyelid margin and leaving it to heal by secondary intention (no sutures). At last recheck (follow-up 354.5 ± 187.8 days), 19/27 dogs (70.4%) had an adequate eyelid conformation, 7/27 dogs (25.9%) were considered under-corrected, and 1/27 dogs (3.7%) was over-corrected. Most owners (81.5%) were satisfied with the surgical results. Most cases (96.3%) had no recurrence of the clinical signs during the entire follow-up period. CONCLUSIONS: Brow rhytidectomy ± Stades-like procedure provide good cosmetic and clinical outcomes in Chow Chow and Shar-Pei dogs, although under correction may occur in severely affected dogs and with advancing time.

Selective extraction and analysis of phenolic acids in herbal plants using Fe3O4@MXene@PEI aerogel.

A magnetic MXene aerogel (Fe3O4@MXene@PEI) was prepared by crosslinking amino modified MXene with polyethyleneimine using epichlorohydrin as a cross-linker. Adsorption properties of Fe3O4@MXene@PEI aerogel for phenolic acids were evaluated by adsorption kinetics and isotherms experiments, showing that the high adsorption affinity was governed by multilayer chemisorption process. An efficient MSPE/HPLC method was developed for the determination of phenolic acids with excellent selectivity, good linearity (0.025-5.0 µg mL-1), low LODs (0.007-0.017 µg mL-1), and satisfactory recoveries (80.0-120.0 %). Moreover, the antioxidant activity of the Fe3O4@MXene@PEI purified compounds was superior to that of the conventional method as demonstrated by the results of scavenging experiments on 2,2 -diphenyl-1-picrylhydrazyl radical scavenging assay. Finally, 65 organic acids were identified in the Fe3O4@MXene@PEI treated honeysuckle extracts by UHPLC-Q-Exactive Orbitrap MS/MS analysis. The proposed sorbent exhibits remarkable promise for the selective separation and purification of organic acids from herbal products.

Effect of Voltage and concentration of polyetherimide on surface morphology and corrosion properties of AZ91D by electro-spin coating.

Magnesium alloys, particularly AZ91D, exhibit promising mechanical properties but are susceptible to corrosion, limiting their widespread industrial applications. This manuscript investigates the impact of voltage and concentration of Polyetherimide (PEI) on surface morphology and corrosion characteristics of AZ91D through electro-spin coating. PEI, known for its high strength and corrosion resistance, is applied using an eco-friendly electro-spin coating method. The study optimizes polymer concentration and applied voltage to enhance the anticorrosive properties of AZ91D. Atomic force microscopy (AFM) and scanning electron microscopy (SEM) reveal the morphological alterations, while electrochemical corrosion tests provide insights into the corrosion resistance. The results show that a moderate PEI concentration (15 %) at 14 kV voltage exhibits the most favorable corrosion resistance, emphasizing the need to optimize both parameters for enhanced protection of AZ91D against corrosion. The results contribute to developing economical and effective corrosion protection techniques for magnesium alloys, mainly for automotive applications.

Gelation and Plugging Performance of Low-Concentration Partially Hydrolyzed Polyacrylamide/Polyethyleneimine System at Moderate Temperature and in Fractured Low-Permeability Reservoir.

HPAM/PEI gel is a promising material for conformance control in hydrocarbon reservoirs. However, its use in low-permeability reservoirs is limited by the high polymer concentrations present. In this study, the gelation performance of an HPAM/PEI system with HPAM < 2.0 wt.% was systematically investigated. The gelation time for HPAM concentrations ranging from 0.4 to 2.0 wt.% varied from less than 1 h to 23 days, with the highest gel strength identified as grade H. The hydrodynamic radius manifested the primary effect of HPAM on the gelation performance. Branched PEI provided superior gelation performance over linear PEI, and the gelation performance was only affected when the molecular weight of the PEI varied significantly. The optimal number ratio of the PEI-provided imine groups and the HPAM-provided carboxylic acid functional groups was approximately 1.6:1~5:1. Regarding the reservoir conditions, the temperature had a crucial effect on the hydrodynamic radius of HPAM. Salts delayed the gelation process, and the order of ionic influence was Ca2+ > Na+ > K+. The pH controlled the crosslinking reaction, primarily due to the protonation degree of PEI and the hydrolysis degree of HPAM, and the most suitable pH was approximately 10.5. Plugging experiments based on a through-type fracture showed that multi-slug plugging could significantly improve the plugging performance of the system, being favorable for its application in fractured low-permeability reservoirs.

Layer-by-layer fabrication of alginate/polyethyleneimine multilayer on magnetic interface with enhanced efficiency in immuno-capturing circulating tumor cells.

BACKGROUND: The technology of capturing circulating tumor cells (CTCs) plays a crucial role in the diagnosis, evaluation of therapeutic efficacy, and prediction of prognosis in lung cancer. However, the presence of complex blood environment often results in severe nonspecific protein adsorption and interferences from blood cells, which negatively impacts the specificity of CTCs capture. There is a great need for development of novel nanomaterials for CTCs capture with prominent anti-nonspecific adsorptions from proteins or blood cells. RESULTS: We present a novel immune magnetic probe Fe3O4@(PEI/AA)4@Apt. The surface of Fe3O4 particles was modified with four layers of PEI/AA composite by layer-by-layer assembly. Furthermore, aptamers targeting epithelial marker EpCAM (SYL3C) and mesenchymal marker CSV (ZY5C) were simultaneously connected on Fe3O4@(PEI/AA)4 to improve the detection of different phenotypic CTCs and reduce false negatives. The results demonstrated that the (PEI/AA)4 coatings not only minimized non-specific protein adsorptions, but also significantly reduced the adsorption rate of red blood cells to a mere 1 %, as a result of which, the Fe3O4@(PEI/AA)4@Apt probe achieved a remarkably high capture efficiency toward CTCs (95.9 %). In the subsequent validation of clinical samples, the probe was also effective in capturing rare CTCs from lung cancer patients. SIGNIFICANCE AND NOVELTY: A (PEI/AA) polymerized composite with controllable layers was fabricated by layer-by-layer self-assembly technique, which displayed remarkable anti-nonspecific adsorption capabilities toward proteins and cells. Importantly, Fe3O4@(PEI/AA)4@Apt probe significantly improved CTCs capture purity in lung cancer patients to 89.36 %. For the first time, this study combined controllable (PEI/AA) layers with magnetic separation to innovatively build a resistant interface that significantly improves the specific capture performances of CTCs, broadening the application of this polymerized composite.

Self-Healable Interfaces with Improved Mechanical Properties Induced by Dynamic Network Reconfiguration in Carbon Fiber-Reinforced Epoxy Laminates.

Interfacial failure in carbon fiber-reinforced epoxy (CFRE) laminates is a prominent mode of failure, attracting significant research attention. The large surface-energy mismatch between carbon fiber (CF) and epoxy results in a weaker interface. This study presents a facile yet effective method for enhancing the interfacial adhesion between CF and epoxy with self-healable interfaces. Two variants of a designer sizing agent, poly(ether imide) (PEI), were synthesized, one without a self-healing property termed BO, and the second one by incorporating disulfide metathesis in one of its monomers that renders self-healing properties at the interface-mediated by network reconfiguration, termed BA. 0.25 wt % of CF was found to be the optimum amount of BO and BA sizing agents. The surface free energy of CF drastically increased and became quite close to the surface energy of epoxy after the deposition of both sizing agents and the higher surface roughness. The improved surface wettability, presence of functional groups, and mechanical interlocking worked in tandem to strengthen the interface. The interlaminar shear strength (ILSS) and flexural strength (FS) of CFRE laminate sized with BO consequently increased by 35% and 22% and of CFRE laminate sized with BA increased by 26% and 19%, respectively. Fractography analysis revealed outstanding bonding between epoxy and PEI-CF, indicating that matrix fracture is the predominant mode of failure. The self-healable interfaces due to the preinstalled disulfide metathesis in the sizing agent resulted in 51% self-healing efficiency in ILSS for BA-sized CFRE laminate. Interestingly, the functional properties, deicing, and EMI shielding effectiveness were not compromised by modification of the interface with this designer sizing agent. This study opens new avenues for interfacial modification to improve the mechanical properties while retaining the key functional properties of the laminates.

Recombinant Protein Production from Stable CHO Cell Pools.

The continuous improvement of expression platforms is necessary to respond to the increasing demand for recombinant proteins that are required to carry out structural or functional studies as well as for their characterization as biotherapeutics. While transient gene expression (TGE) in mammalian cells constitutes a rapid and well-established approach, non-clonal stably transfected cells, or "pools," represent another option, which is especially attractive when recurring productions of the same protein are required. From a culture volume of just a few liters, stable pools can provide hundreds of milligrams to gram quantities of high-quality secreted recombinant proteins.In this chapter, we describe a highly efficient and cost-effective procedure for the generation of Chinese Hamster Ovary cell stable pools expressing secreted recombinant proteins using commercially available serum-free media and polyethylenimine (PEI) as the transfection reagent. As a specific example of how this protocol can be applied, the production and downstream purification of recombinant His-tagged trimeric SARS-CoV-2 spike protein ectodomain (SmT1) are described.

Dielectric Properties of PEEK/PEI Blends as Substrate Material in High-Frequency Circuit Board Applications.

Substrate materials for printed circuit boards must meet ever-increasing requirements to keep up with electronics technology development. Especially in the field of high-frequency applications such as radar and cellular broadcasting, low permittivity and the dielectric loss factor are key material parameters. In this work, the dielectric properties of a high-temperature, thermoplastic PEEK/PEI blend system are investigated at frequencies of 5 and 10 GHz under dried and ambient conditions. This material blend, modified with a suitable filler system, is capable of being used in the laser direct structuring (LDS) process. It is revealed that the degree of crystallinity of neat PEEK has a notable influence on the dielectric properties, as well as the PEEK phase structure in the blend system developed through annealing. This phenomenon can in turn be exploited to minimize permittivity values at 30 to 40 wt.-% PEI in the blend, even taking into account the water uptake present in thermoplastics. The dielectric loss follows a linear mixing rule over the blend range, which proved to be true also for PEEK/PEI LDS compounds.

Case report: Radiofrequency-induced thermal burn injury in a dog after magnetic resonance imaging.

A 10-year-old male Shar-Pei was referred for lethargy and proprioceptive deficits of the left thoracic limb. An magnetic resonance imaging (MRI) examination of the cervical spinal column and the brain was performed. The MRI examination of the brain was normal. A left-sided C3-C4 intervertebral disc extrusion with spinal cord compression was diagnosed. Medical treatment was elected. Within a week after the MRI examination, the dog presented with deep partial-thickness skin burn wounds in both axillae. Since the specific absorption rate had not exceeded the safety limits during any of the scans and no other procedures or circumstances were identified that could possibly have resulted in burn injuries, the thermal burn injuries were diagnosed as radiofrequency (RF) burns. The wounds healed by secondary intent over the next month. RF burns are the most reported complication in humans undergoing MRI but have not been reported in veterinary patients. Clinicians and technicians should consider the potential risk for RF burns in veterinary patients and take precautions regarding positioning of the patient and take notice of any signs of burn injury when performing follow-up examinations.

Screening for undiagnosed pancreatic exocrine insufficiency (PEI) in a cohort of diabetic patients using faecal elastase testing and PEI scoring system.

INTRODUCTION: Type 1 and type 2 diabetes mellitus (DM) are often accompanied by mild forms of pancreatic exocrine insufficiency (PEI). The prevalence rates of PEI in diabetic patients are unclear and variable depending on the testing modality and the studies published. The clinical consequences of PEI in diabetics are also not well defined. AIM: We aimed to determine the prevalence of PEI in a diabetic cohort using the faecal elastase-1 (FE-1) assay as a screening test and to validate a patient-reported symptom-based scoring system, the (PEI-S) for diagnosing PEI within this patient population. METHODS: Two hundred and three diabetic patients attending diabetic and gastroenterology outpatients of a university hospital without previously known PEI were recruited for the study. Demographic parameters, PEI score (PEI-S), and glycated hemoglobin (HBA1c) were documented in standardized data sheets, and a stool sample was obtained. A FE-1 value < 200 µg/g and or a PEIS of > 0.6 was used as the screening cut-off for PEI. RESULTS: One hundred sixty-six patients returned faecal samples. The prevalence of PEI, as measured by low FE-1, was 12%. Smoking was associated with an increased risk of developing PEI in this diabetic population. No other independent risk factors were identified. The PEI-S system did not differentiate between people with diabetes having a normal and low FE1. CONCLUSION: 12% of this mixed, real-life cohort of type 1 and 2 DM patients had undiagnosed PEI, as defined by an FE-1 score of less than 200 µg/g. While this may appear low, given the rising prevalence of type 2 DM worldwide, there is likely an unrecognized burden of PEI, which has long-term health consequences for those affected. The PEI-S, a symptom-scoring system for patients with PEI, did not perform well in this patient group.

A novel electrochemical aptasensor based on AgPdNPs/PEI-GO and hollow nanobox-like Pt@Ni-CoHNBs for procymidone detection.

Herein, an aptasensor based on a signal amplification strategy was developed for the sensitive detection of procymidone (PCM). AgPd nanoparticles/Polenimine Graphite oxide (AgPdNPs/PEI-GO) was weaned as electrode modification material to facilitate electron transport and increase the active sites on the electrode surface. Besides, Pt@Ni-Co nanoboxes (Pt@Ni-CoHNBs) were utilized to be carriers for signaling tags, after hollowing ZIF-67 and growing Pt, the resulting Pt@Ni-CoHNBs has a tremendous amounts of folds occurred on the surface, enables it to carry a larger quantity of thionine, thus amplify the detectable electrochemical signal. In the presence of PCM, the binding of PCM to the signal probe would trigger a change in electrical signal. The aptasensor was demonstrated with excellent sensitivity and a low detection limit of 0.98 pg·mL-1, along with a wide linear range of 1 µg·mL-1 to 1 pg·mL-1. Meanwhile, the specificity, stability and reproducibility of the constructed aptasensor were proved to be satisfactory.

Metagenomics profiling of the microbial community and functional differences in solid-state fermentation vinegar starter (seed Pei) from different Chinese regions.

Introduction: The starter used in solid-state fermentation (SSF) vinegar, known as seed Pei is a microbial inoculant from the previous batch that is utilized during the acetic acid fermentation stage. The seed Pei, which has a notable impact on vinegar fermentation and flavor, is under-researched with comparative studies on microorganisms. Methods: Herein metagenomics was employed to reveal the microbes and their potential metabolic functions of four seed Pei from three regions in China. Results: The predominant microbial taxa in all four starters were bacteria, followed by viruses, eukaryotes, and archaea, with Lactobacillus sp. or Acetobacter sp. as main functional taxa. The seed Pei used in Shanxi aged vinegar (SAV) and Sichuan bran vinegar (SBV) exhibited a higher similarity in microbial composition and distribution of functional genes, while those used in two Zhenjiang aromatic vinegar (ZAV) differed significantly. Redundancy analysis (RDA) of physicochemical factors and microbial communities indicated that moisture content, pH, and reducing sugar content are significant factors influencing microbial distribution. Moreover, seven metagenome-assembled genomes (MAGs) that could potentially represent novel species were identified. Conclusions: There are distinctions in the microbiome and functional genes among different seed Pei. The vinegar starters were rich in genes related to carbohydrate metabolism. This research provides a new perspective on formulating vinegar fermentation starters and developing commercial fermentation agents for vinegar production.

Applicability of the Pancreatic Exocrine Insufficiency Test (PEI-TEST) in Pediatric Patients.

In mild cases, it is difficult to diagnose pancreatic exocrine insufficiency (PEI). There is no gold standard method for the diagnosis of PEI. A reliable method is needed for preliminary diagnosis of PEI. The PEI-TEST was applied to the patients with nonspecific gastrointestinal complaints. Serum amylase, lipase, serum trypsinogen, and fecal elastase 1 (FE-1) were analyzed from each patient. According to the PEI-TEST, PEI was present in 42 (47.7%) and PEI was not present in 46 (52.3%) patients. No significant difference was observed between the 2 groups with regard to age, gender and amylase, lipase, serum trypsinogen, and FE-1. When an FE-1 value of <200 µg/dL was considered as indicating PEI, the sensitivity and specificity of the test were found to be 47.4% and 52.2%, respectively. Although it is promising that PEI-TEST is a validated test in our country and suitable for our society, it is not suitable for pediatric patients.

Preparation of multifunctional PET membrane and its application in high-efficiency filtration and separation in complex environment.

Nowadays, effluent treatment is a severe challenge mainly because of its complex composition, which includes oil, heavy metal ions, and dyes. Developing new intelligent membranes is one of the strategies to tackle these significant challenges in wastewater treatment. In this study, we fabricated asymmetric polyethylene glycol terephthalate (PET) membranes by grafting cross-linked poly (itaconic anhydride) (CL-PITA) nanoparticles onto the irradiated face. These nanoparticles were then functionalized with polyethyleneimine (PEI) and protonated with HCl to introduce numerous active electropositive amine groups. The fundamental purpose was to increase surface roughness, introduce numerous hydrophilic groups, and modify it to create a multi-functional PET membrane to separate complex environments. The promising results demonstrated that the protonated PET-g-ITA/DVB(10)-cat membrane exhibited excellent separation efficiencies (SE) for water/light oil, water/heavy oil and oil-in-water (O/W) emulsion. Compared to PET-g-ITA/DVB(0)-cat, it showed superior performance in SE for O/W emulsion and flux decay for water/light oil after 10 cycles. More interestingly, owing to numerous positively charged active amino groups and negativley charged carboxylate groups, the intelligent membrane exhibited a high removal rate of ca. 90 % for anionic dye (congo red) and heavy metals (Cu2+ and Co2+), showing great potential in complex water treatment environments.

[Opening experiments: synthesis, purification, and characterization of polyethyleneimine-modified carbon dots].

Open experiments are an effective means of cultivating top-notch innovative talents. Based on student interests, research hotspots and our laboratory conditions, an experimental scheme was designed. In this experiment, polyethyleneimine modified carbon dots (PEI-CDs) were prepared via a one-step hydrothermal method using citric acid (CA) as the carbon source and PEI as the surface passivator. First, CA and PEI were completely dissolved in 0.1 mol/L HCl and transferred into an autoclave. The autoclave was heated to 130 ℃ for 2 h. PEI-CDs solution was obtained. After cooling to room temperature, the solution was concentrated to 2 mL by rotary evaporation. Finally, the PEI-CDs were precipitated, washed with ethanol, and dried under vacuum at 70 ℃ for 12 h. The obtained PEI-CDs were characterized by fluorescence spectrophotometry, absorption spectrophotometry, infrared spectrometry, and transmission electron microscopy. The results indicated that anhydrous-ethanol precipitation is a simple, rapid, economical, and green purification method. The as-prepared PEI-CDs had unique properties, such as good water solubility, high luminescence, uniform particle sizes, and good stability. Through this open experiment, students can not only master the operation of large-scale instruments but also enhance their interest in scientific research.

Polytomous Effectiveness Indicators in Complex Problem-Solving Tasks and Their Applications in Developing Measurement Model.

Recent years have witnessed the emergence of measurement models for analyzing action sequences in computer-based problem-solving interactive tasks. The cutting-edge psychometrics process models require pre-specification of the effectiveness of state transitions often simplifying them into dichotomous indicators. However, the dichotomous effectiveness becomes impractical when dealing with complex tasks that involve multiple optimal paths and numerous state transitions. Building on the concept of problem-solving, we introduce polytomous indicators to assess the effectiveness of problem states d s and state-to-state transitions Δ d s → s ' . The three-step evaluation method for these two types of indicators is proposed and illustrated across two real problem-solving tasks. We further present a novel psychometrics process model, the sequential response model with polytomous effectiveness indicators (SRM-PEI), which is tailored to encompass a broader range of problem-solving tasks. Monte Carlo simulations indicated that SRM-PEI performed well in the estimation of latent ability and transition tendency parameters across different conditions. Empirical studies conducted on two real tasks supported the better fit of SRM-PEI over previous models such as SRM and SRMM, providing rational and interpretable estimates of latent abilities and transition tendencies through effectiveness indicators. The paper concludes by outlining potential avenues for the further application and enhancement of polytomous effectiveness indicators and SRM-PEI.

Construction of resveratrol and quercetin nanoparticles based on folic acid targeted Maillard products between Jiuzao glutelin isolate and carboxymethyl chitosan: Improved stability and function.

Advanced targeted nanoparticles (NPs) were designed to enhance the targeted delivery of resveratrol (RES) and quercetin (QUE) by utilizing carboxymethyl chitosan (CTS) and Jiuzao glutelin isolate (JGI) conjugates. Briefly, RES and QUE were encapsuled within CTS-JGI-2 (CTS/JGI, m/m, 2:1). The carrier's targeting properties were further improved through the incorporation of folic acid (FA) and polyethylenimine (PEI). Moreover, the stability against digestion was enhanced by incorporating baker yeast cell walls (BYCWs) to construct RES-QUE/FA-PEI/CTS-JGI-2/MAT/BYCW NPs. The results demonstrated that FA-PEI/CTS-JGI-2/MAT/BYCW NPs could improve cellular uptake and targeting property of RES and QUE through endocytosis of folic acid receptors (FOLRs). Additionally, RES-QUE successfully alleviated LPS- and DSS-induced inflammation by regulating NF-κB/IkBa/AP-1 and AMPK/SIRT1signaling pathways and reducing the secretion of inflammatory mediators and factors. These findings indicate FA-PEI/CTS-JGI-2/MAT/BYCW NPs hold promise as an oral drug delivery system with targeted delivery capacities for functional substances prone to instability in dietary supplements.

Spray-drying of PEI-/PPI-based nanoparticles for DNA or siRNA delivery.

Spray-drying of nucleic acid-based drugs designed for gene therapy or gene knockdown is associated with many advantages including storage stability and handling as well as the possibility of pulmonary application. The encapsulation of nucleic acids in nanoparticles prior to spray-drying is one strategy for obtaining efficient formulations. This, however, strongly relies on the definition of optimal nanoparticles, excipients and spray-drying conditions. Among polymeric nanoparticles, polyethylenimine (PEI)-based complexes with or without chemical modifications have been described previously as very efficient for gene or oligonucleotide delivery. The tyrosine-modification of linear or branched low molecular weight PEIs, or of polypropylenimine (PPI) dendrimers, has led to high complex stability, improved cell uptake and transfection efficacy as well as high biocompatibility. In this study, we identify optimal spray-drying conditions for PEI-based nanoparticles containing large plasmid DNA or small siRNAs, and further explore the spray-drying of nanoparticles containing chemically modified polymers. Poly(vinyl alcohol) (PVA), but not trehalose or lactose, is particularly well-suited as excipient, retaining or even enhancing transfection efficacies compared to fresh complexes. A big mesh size is critically important as well, while the variation of the spray-drying temperature plays a minor role. Upon spray-drying, microparticles in a âˆ¼ 3.3 - 8.5 µm size range (laser granulometry) are obtained, dependent on the polymers. Upon their release from the spray-dried material, the nanoparticles show increased sizes and markedly altered zeta potentials as compared to their fresh counterparts. This may contribute to their high efficacy that is seen also after prolonged storage of the spray-dried material. We conclude that these spray-dried systems offer a great potential for the preparation of nucleic acid drug storage forms with facile reconstitution, as well as for their direct pulmonary application as dry powder.