Protein Corona Formation on Colloidal Polymeric Nanoparticles and Polymeric Nanogels: Impact on Cellular Uptake, Toxicity, Immunogenicity, and Drug Release Properties.

The adsorption of biomolecules to the surface of nanoparticles (NPs) following administration into biological environments is widely recognized. In particular, the "protein corona" is well understood in terms of formation kinetics and impact upon the biological interactions of NPs. Its presence is an essential consideration in the design of therapeutic NPs. In the present study, the protein coronas of six polymeric nanoparticles of prospective therapeutic use were investigated. These included three colloidal NPs-soft core-multishell (CMS) NPs, plus solid cationic Eudragit RS (EGRS), and anionic ethyl cellulose (EC) nanoparticles-and three nanogels (NGs)-thermoresponsive dendritic-polyglycerol (dPG) nanogels (NGs) and two amino-functionalized dPG-NGs. Following incubation with human plasma, protein coronas were characterized and their biological interactions compared with pristine NPs. All NPs demonstrated protein adsorption and increased hydrodynamic diameters, although the solid EGRS and EC NPs bound notably more protein than the other tested particles. Shifts toward moderately negative surface charges were also observed for all corona bearing NPs, despite varied zeta potentials in their pristine states. While the uptake and cellular adhesion of the colloidal NPs in primary human keratinocytes and human umbilical vein endothelial cells were significantly decreased when bearing the protein corona, no obvious impact was seen in the NGs. By contrast, corona bearing NGs induced marked increases in cytokine release from primary human macrophages not seen with corona bearing colloidal NPs. Despite this, no apparent enhancement to in vitro toxicity was noted. Finally, drug release from EGRS and EC NPs was assessed, where a decrease was seen in the EGRS NPs alone. Together these results provide a direct comparison of the physical and biological impact the protein corona has on NPs of widely varied character and in particular highlights a distinction between the corona's effects on NGs and colloidal NPs.

Identification of an anti-inflammatory potential of Eriodictyon angustifolium compounds in human gingival fibroblasts.

Polyphenol-rich plant extracts have been shown to possess anti-inflammatory activity against oral pathogen-induced cytokine release in model systems of inflammation. Here, it was hypothesized that a flavanone-rich extract of E. angustifolium exhibits an anti-inflammatory potential against endotoxin-induced inflammatory response in human gingival fibroblasts (HGF-1). HGF-1 cells were stimulated with lipopolysaccharide from Porphyromonas gingivalis (pg-LPS) to release pro-inflammatory cytokines. Concentrations of interleukins IL-6 and IL-8 and macrophage chemoattractant protein-1 in the incubation media upon stimulation were determined by means of magnetic bead analysis. A crude ethanol/water extract of E. angustifolium (EE) was fractionated via gel permeation chromatography into a flavanone-rich fraction (FF) and an erionic acid-rich fraction (EF). Individual flavanones and erionic acids as well as EE, EF and FF were tested in the pg-LPS-stimulated HGF-1 cells for their anti-inflammatory potential. The E. angustifolium extract possessed anti-inflammatory potential in this model system, attenuating the pg-LPS-induced release of IL-6 by up to 52.0 ± 15.5%. Of the individual flavanones, eriodictyol and naringenin had the most pronounced effect. However, a mixture of the flavanones did not possess the same effect as the entire flavanoid fraction, indicating that other compounds may contribute to the anti-inflammatory potential of E. angustifolium. For the first time, an anti-inflammatory potential of E. angustifolium and containing erionic acids has been determined.

Feasibility study for intraepidermal delivery of proteins using a solid microneedle array.

Solid microneedles (MN) are a promising tool for dermal drug delivery. Particular focus lies on the field of vaccination due to pain-free, safe, hygienic and patient compliant antigen deposition. Diverse coating techniques and formulations have been developed to preserve vaccine activity and to enable targeted drug deposition in the skin. Process and long-term storage stability of coated MN, however, have not yet been studied in detail. Hence, a feasibility study was conducted determining the appropriate needle length (300 µm) for local intraepidermal protein delivery. Moreover, a protein-stabilizing coating formulation was developed. Coating of the MN resulted in protein concentrations between 10 and 23 µg, 90% of the bioactivity of the model protein asparaginase was maintained for 3 months. Skin experiments verified the intraepidermal deposition of 68.0 ± 11.7% of the coated model protein after single application. Slightly increased interleukin 8 levels right after MN insertion indicated minor skin irritation due to the mechanical piercing stress. Thus, specifically highlighting protein stabilization during storage, we demonstrated that selective intraepidermal deposition of proteins or peptides' using solid MN is a feasible approach.

Recent advances in topical delivery of proteins and peptides mediated by soft matter nanocarriers.

Proteins and peptides are increasingly important therapeutics for the treatment of severe and complex diseases like cancer or autoimmune diseases due to their high specificity and potency. Their unique structure and labile physicochemical properties, however, require special attention in the production and formulation process as well as during administration. Aside from conventional systemic injections, the topical application of proteins and peptides is an appealing alternative due to its non-invasive nature and thus high acceptance by patients. For this approach, soft matter nanocarriers are interesting delivery systems which offer beneficial properties such as high biocompatibility, easiness of modifications, as well as targeted drug delivery and release. This review aims to highlight and discuss technological developments in the field of soft matter nanocarriers for the delivery of proteins and peptides via the skin, the eye, the nose, and the lung, and to provide insights in advantages, limitations, and practicability of recent advances.

Astringency is a trigeminal sensation that involves the activation of G protein-coupled signaling by phenolic compounds.

Astringency is an everyday sensory experience best described as a dry mouthfeel typically elicited by phenol-rich alimentary products like tea and wine. The neural correlates and cellular mechanisms of astringency perception are still not well understood. We explored taste and astringency perception in human subjects to study the contribution of the taste as well as of the trigeminal sensory system to astringency perception. Subjects with either a lesion or lidocaine anesthesia of the Chorda tympani taste nerve showed no impairment of astringency perception. Only anesthesia of both the lingual taste and trigeminal innervation by inferior alveolar nerve block led to a loss of astringency perception. In an in vitro model of trigeminal ganglion neurons of mice, we studied the cellular mechanisms of astringency perception. Primary mouse trigeminal ganglion neurons showed robust responses to 8 out of 19 monomeric phenolic astringent compounds and 8 polymeric red wine polyphenols in Ca(2+) imaging experiments. The activating substances shared one or several galloyl moieties, whereas substances lacking the moiety did not or only weakly stimulate responses. The responses depended on Ca(2+) influx and voltage-gated Ca(2+) channels, but not on transient receptor potential channels. Responses to the phenolic compound epigallocatechin gallate as well as to a polymeric red wine polyphenol were inhibited by the Gαs inactivator suramin, the adenylate cyclase inhibitor SQ, and the cyclic nucleotide-gated channel inhibitor l-cis-diltiazem and displayed sensitivity to blockers of Ca(2+)-activated Cl(-) channels.