Artificial nanoparticles accumulate a protein corona layer in biological fluids, which significantly influences their bioactivity. As nanosized obligate intracellular parasites, viruses share many biophysical properties with artificial nanoparticles in extracellular environments and here we show that respiratory syncytial virus (RSV) and herpes simplex virus type 1 (HSV-1) accumulate a rich and distinctive protein corona in different biological fluids. Moreover, we show that corona pre-coating differentially affects viral infectivity and immune cell activation. In addition, we demonstrate that viruses bind amyloidogenic peptides in their corona and catalyze amyloid formation via surface-assisted heterogeneous nucleation. Importantly, we show that HSV-1 catalyzes the aggregation of the amyloid β-peptide (Aβ₄₂), a major constituent of amyloid plaques in Alzheimer’s disease, in vitro and in animal models. Our results highlight the viral protein corona as an acquired structural layer that is critical for viral–host interactions and illustrate a mechanistic convergence between viral and amyloid pathologies.

Extracellular vesicles (EVs) have been established to play important roles in cell-cell communication and shown promise as therapeutic agents. However, we still lack a basic understanding of how cells respond upon exposure to EVs from different cell sources at various doses. Thus, we treated fibroblasts with EVs from 12 different cell sources at doses between 20 and 200,000 per cell, analyzed their transcriptional effects, and functionally confirmed the findings in various cell types in vitro, and in vivo using single-cell RNA sequencing. Unbiased global analysis revealed EV dose to have a more significant effect than cell source, such that high doses down-regulated exocytosis and up-regulated lysosomal activity. However, EV cell source–specific responses were observed at low doses, and these reflected the activities of the EV’s source cells. Last, we assessed EV-derived transcript abundance and found that immune cell-derived EVs were most associated with recipient cells. Together, this study provides important insights into the cellular response to EVs.

Extracellular vesicles (EVs) are nanosized cell‐derived vesicles produced by all cells, which provide a route of intercellular communication by transmitting biological cargo. While EVs offer promise as therapeutic agents, the molecular mechanisms of EV biogenesis are not yet fully elucidated, in part due to the concurrence of numerous interwoven pathways which give rise to heterogenous EV populations in vitro. The equilibrium between the EV‐producing pathways is heavily influenced by factors in the extracellular environment, in such a way that can be taken advantage of to boost production of engineered EVs. In this study, a quantifiable EV‐engineering approach is used to investigate how different cell media conditions alter EV production. The presence of serum, exogenous EVs, and other signaling factors in cell media alters EV production at the physical, molecular, and transcriptional levels. Further, it is demonstrated that the ceramide‐dependent EV biogenesis route is the major pathway to production of engineered EVs during optimized EV‐production. These findings suggest a novel understanding to the mechanisms underlying EV production in cell culture which can be applied to develop advanced EV production methods.

Introduction: Vaginal candidiasis remains a recurrent fungal infection affecting millions of women worldwide, necessitating innovative local delivery systems to overcome poor drug solubility and mucosal barriers. This study introduces Dual-Functional Hybrid Cationic PEGylated Proniosomes (DHCPP) as a smart nano-platform designed to boost the vaginal delivery of Fenticonazole Nitrate (FTN). Methods: DHCPP systems were fabricated via the coacervation phase separation method and optimized using a full 2 ³ factorial design, achieving a high desirability value of 0.931. The optimized DHCPP exhibited an encapsulation efficiency of 91.61%, particle size of 238.85 nm, and zeta potential of +58.85 mV, ensuring colloidal stability and efficient mucosal interaction. Results: In-vitro characterization using TEM and FTIR verified the formation of uniform spherical vesicles and successful FTN encapsulation without chemical incompatibility. Mucoadhesion testing revealed superior adhesive strength, indicating prolonged vaginal residence, while drug release followed a diffusion-controlled pattern. The optimized DHCPP was incorporated into a carbopol-based gel exhibiting pseudo-plastic rheology and pH compatibility with the vaginal environment. Multi-scale ex vivo and in vivo evaluations revealed a 2.36-fold permeation enhancement compared to FTN gel, consistent with deeper mucosal penetration observed via confocal microscopy. The microbiological assessment indicated a pronounced reduction in MIC and MFC values and a remarkable improvement in biofilm inhibitory effect, highlighting enhanced antifungal efficacy. Histopathological examination verified the mucosal safety of the optimized gel. Conclusion: The developed DHCPP represents an innovative, multifunctional, and biocompatible delivery system offering enhanced vaginal permeation, prolonged retention, and potent antifungal activity for the effective management of vaginal candidiasis.

This study introduces and statistically optimizes novel Tetra-Synergistic Bilosomes (TSB), an advanced nano-platform for topical delivery of voriconazole (VOR) in otomycosis therapy. The term “Tetra-Synergistic” reflects the incorporation of four complementary components: Cremophor® EL, sodium deoxycholate, Brij® 58, and Brij® S2, working in synergy to enhance therapeutic efficacy. TSB was fabricated using the thin-film hydration method and optimized through a 2 ³ D-optimal design. Three formulation factors were investigated: Cremophor® EL: VOR ratio, sodium deoxycholate: cholesterol ratio, and Brij® 58: Brij® S2 ratio, with the optimization goal of maximizing EE%, minimizing vesicular size, and maintaining ZP within the acceptable stability range. The model demonstrated excellent predictability, achieving a desirability value of 0.888. The optimized TSB exhibited high EE% (91.6%), a suitably small VS (217.9nm), and stable ZP (− 24.1mV). FTIR confirmed VOR entrapment, while TEM revealed nano-sized spherical vesicles. Moreover, TSB displayed a biphasic In-vitro release profile and remained stable for three months under refrigeration. Importantly, microbiological evaluation confirmed the superior antifungal performance of TSB. Compared with VOR suspension, TSB showed a larger inhibition zone, a lower minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC), and a faster fungicidal effect, eradicating fungal growth in 33% less time. Ex-vivo permeation studies revealed a 2.18-fold enhancement ratio, supported by confocal laser scanning microscopy confirming deeper tissue penetration. Histopathological analysis further validated the safety of topical application without any tissue damage. Collectively, these results establish TSB as a pioneering, microbiologically potent, and clinically promising nano-vesicular system for the effective management of otomycosis.

The study aimed to formulate and evaluate levofloxacin hemihydrate ocular in situ gels along with freshly prepared disappearing preservative reported to be safer to human eyes. Formulae were prepared using thermosensitive (PF127 and PF68) or ion-activated (Gelrite) polymers. They were evaluated for gelation temperature (GT), capacity, content uniformity, pH, rheological behavior, in vitro drug release with kinetic analysis. Best formulae were exposed to storage effect to select the optimum formula that was subjected to different sterilization methods and in vivo evaluation. The prepared disappearing preservative (sodium perborate monohydrate) proved to be active oxidative preservative and compatible with our formulae. F9 (24% PF127, 15% PF 68, 0.5% levofloxacin hemihydrate, and 0.0025% sodium perborate monohydrate) showed prolonged drug release (12 h), acceptable GT, viscosity, and pH. It remained stable over 3 months at two temperatures and was best sterilized by filtration. It showed longer residence time (12 h) in rabbits' eye fluids compared with the Levoxin® eye drops (4 h). This successful attempt of using thermo-gelling system along with a disappearing type of preservatives would allow the use of these systems to achieve sustained release of antimicrobial drugs with minimum risk of eye damage improving patient compliance and treatment efficacy.