Nanoparticles Surface Chemistry Influence on Protein Corona Composition and Inflammatory Responses.

Nanoparticles are widely used for biomedical applications such as vaccine, drug delivery, diagnostics, and therapeutics. This study aims to reveal the influence of nanoparticle surface functionalization on protein corona formation from blood serum and plasma and the subsequent effects on the innate immune cellular responses. To achieve this goal, the surface chemistry of silica nanoparticles of 20 nm diameter was tailored via plasma polymerization with amine, carboxylic acid, oxazolines, and alkane functionalities. The results of this study show significant surface chemistry-induced differences in protein corona composition, which reflect in the subsequent inflammatory consequences. Nanoparticles rich with carboxylic acid surface functionalities increased the production of pro-inflammatory cytokines in response to higher level of complement proteins and decreased the number of lipoproteins found in their protein coronas. On another hand, amine rich coatings led to increased expressions of anti-inflammatory markers such as arginase. The findings demonstrate the potential to direct physiological responses to nanomaterials via tailoring their surface chemical composition.

Self-sterilizing antibacterial silver-loaded microneedles.

Microneedle patches have become an exciting means for transdermal delivery of various therapeutics. Herein, we report on self-sterilizing dissolving nanosilver-loaded microneedle patches created from carboxymethylcellulose capable of suppressing microbial pathogen growth at the insertion site.

Hyaluronic Acid-Modified Porous Silicon Films for the Electrochemical Sensing of Bacterial Hyaluronidase.

The development of enzyme-responsive hyaluronic acid methacrylate (HYAMA)-coated porous silicon (pSi) films and their application in electrochemical diagnostic devices for the in situ detection of the enzyme hyaluronidase (hyal), which is secreted by Staphylococcus aureus (S. aureus) bacteria, are reported. The approach relies on a HYAMA-pSi electrode made of thermally hydrocarbonized pSi (pSi-THC) that is impregnated with crosslinked HYAMA/polyethylene glycol diacrylate (PEGDA) hydrogels. The enzymatic degradation of HYAMA by bacterial hyal is monitored by differential pulse voltammetry (DPV) utilizing pSi-THC as a working electrode and ferro/ferricyanide (FF) as external redox probe. The degradation of HYAMA results in reduced diffusion of the redox probe through the partially charged film, thereby enabling the detection of hyal by DPV. In addition to the determination of the concentration-dependent response in NaOAc buffer (pH 5.2), the detection of hyal as indicator for the presence of S. aureus bacteria above a threshold level in bacterial supernatants and artificial wound fluid is highlighted.

Protective effect of sodium stearate on the moisture-induced deterioration of hygroscopic spray-dried powders.

Amorphous powders are thermodynamically unstable, significantly impacting the processing, storage and performance of a product. Therefore, stabilization of the amorphous contents is in demand. In this study, disodium cromoglycate (DSCG) powder was chosen as a model drug because it is amorphous and highly hygroscopic after spray drying. Sodium stearate (NaSt) was co-spray dried with DSCG at various concentrations (10, 50 and 90% w/w) to investigate its effect against moisture-induced deterioration on the in vitro aerosolization performance of DSCG. Particle size distribution and morphology were measured by laser diffraction and scanning electron microscopy (SEM). Physicochemical properties of the powders were analysed by X-ray powder diffraction (XRPD) and dynamic vapour sorption (DVS). Particle surface chemistry was analysed by the time-of-flight secondary ion mass spectrometry (ToF-SIMS). In vitro dissolution behaviours of the spray-dried (SD) powders were tested by the Franz cell apparatus. In vitro aerosolization performance of SD formulations stored at different relative humidity (RH) was evaluated by a multi-stage liquid impinger (MSLI), using an Osmohaler® at 100 L/min. Results showed that adding NaSt in the formulation not only increased the aerosolization performance of DSCG significantly, but also effectively reduced the deleterious impact of moisture. No significant difference was found in the fine particle fraction (FPF) of formulations containing NaSt before and after storage at both 60% and 75% RH for one week. However, after one month storage at 75% RH, SD formulation containing 10% NaSt showed a reduction in FPF, while formulations containing 50% or 90% NaSt showed no change. The underlying mechanism was that NaSt increased the crystallinity of the powders and its presence on the particle surface reduced particle aggregations and cohesiveness. However, NaSt at high concentration could reduce dissolution rate, which needs to be taken into consideration.

Antibiofouling Properties of Plasma-Deposited Oxazoline-Based Thin Films.

Infections caused by the bacterial colonization of medical devices are a substantial problem to patients and healthcare. Biopassive polyoxazoline coatings are attracting attention in the biomedical field as one of the potential solutions to this problem. Here, we present an original and swift way to produce plasma-deposited oxazoline-based films for antifouling applications. The films developed via the plasma deposition of 2-methyl-2-oxazoline and 2-ethyl-2-oxazoline have tunable thickness and surface properties. Diverse film chemistries were achieved by tuning and optimizing the deposition conditions. Human-derived fibroblasts were used to confirm the biocompatibility of oxazoline derived coatings. The capacity of the coatings to resist biofilm attachment was studied as a function of deposition power and mode (i.e., continuous wave or pulsed) and precursor flow rates for both 2-methyl-2-oxazoline and 2-ethyl-2-oxazoline. After careful tuning of the deposition parameters films having the capacity to resist biofilm formation by more than 90% were achieved. The substrate-independent and customizable properties of the new generation of plasma deposited oxazoline thin films developed in this work make them attractive candidates for the coating of medical devices and other applications where bacteria surface colonization and biofilm formation is an issue.

Properties and reactivity of polyoxazoline plasma polymer films.

Polyoxazolines arise as a promising new class of polymers for biomedical applications, but creating oxzoline-based coatings via conventional methods is challenging. Herein, nanoscale polyoxazoline coatings were generated via a single step plasma deposition process. The effects of plasma deposition conditions on the film stability, structure and chemical group density were investigated. Detailed examination of the physical and chemical properties of plasma deposited polyoxazoline via XPS, FTIR, contact angle and ellipsometry unravels the complex functionality of the films. Partial retention of the oxazoline ring facilitates a covalent reaction with the carboxylic acid groups present on nanoparticles and biomolecules. Surface bound proteins effectively retain their bioactivity, therefore a vast range of potential applications unlocks for plasma deposited polyoxazoline coatings in the field of biosensing, medical arrays and diagnosis.