Electrospun nanofibrous dressings present suitable characteristics to be used in wound healing, such as high porosity and high surface area-to-volume ratio. In this study, a wound dressing based on PLGA and Aloe vera containing lipid nanoparticles (NLCs) was developed. NLCs were added in order to add a lipid component that could avoid the adhesion of the dressing to the wound and improve its handling. Membranes with and without NLCs were composed of uniform fibers of about 1 µm in diameter. Their porosity was above 80 % and their thickness was about 160 µm. Both dressings showed similar water vapour transmission rate 1100 g/m2day. The formulation containing NLCs presented a higher ultimate tensile strength (2.61 ± 0.46 MPa) and a higher water uptake. Both formulations were biocompatible in vitro. Furthermore, the cell adhesion assay demonstrated that both membranes had a low adherence profile, although it was lower with the dressing containing NLCs. Finally, their efficacy was evaluated in a full thickness wound healing assay conducted in db/db mice, where both enhanced healing similarly. Accordingly, the PLGA-AV-NLC membrane might be a promising strategy for the treatment of chronic wounds, since it improved handling in comparison to the formulation without NLCs.

Maytansine and its related analogues are a class of highly potent anti-proliferation agents that have failed to be exploited as clinical drugs for human therapy due to unacceptable systemic toxicity. Here, we delineate a novel strategy that combines rational drug conjugation with subsequent nanoparticle assembly to systemically deliver this highly potent and toxic drug. To demonstrate this concept, we covalently coupled the thiolated maytansine derivative, the DM1 agent, to amphiphilic block co-polymers, polyethylene glycol (PEG)-block-polylactide (PLA), in varying molecular weights to generate two prodrug constructs (i.e., PEG2K-PLA2K-DM1 and PEG2K-PLA4K-DM1) via the maleimide-thiol reaction. The resulting two constructs are amenable to self-assembly in aqueous solutions and are systemically injectable for preclinical studies. In vivo evaluations indicate that PEG-PLA-DM1 conjugate-assembled nanoparticles (NPs) display substantially reduced drug toxicity compared to the free drug forms and NPs that physically encapsulate DM1. Furthermore, following systemic administration, these nanodrugs produced superior therapeutic efficacy over free DM1 in a colon tumor xenograft-bearing mouse model. Therefore, this study provides evidence that the conjugation of toxic drugs to assembling copolymers enables the alleviation of cancer drug toxicity and effective delivery of anticancer drugs. Thus, this DM1-formulated platform represents a new generation of nanotherapeutics that are available for further clinical evaluation.

Mesoporous silica nanoparticles (MSNs) represent one of the most promising drug delivery systems. MSNs have attracted considerable attention in recent years both in industry and biomedicine due to their unique properties. Thus, evaluation of the toxic effects of MSNs is necessary before the biomedical and clinical applications. We investigated the in vivo effect of MSNs on the production of reactive oxygen species (ROS), antioxidant defenses and histology of the heart and lung. Rats received 25, 50, 100 and 200 mg/kg body weight of synthesized MSNs intraperitoneally for 30 days and samples were collected for analysis. MSNs induced significant increase in serum cardiac function markers, tumor necrosis factor alpha and lipids. MSNs-induced rats exhibited anemia, thrombocytopenia, leukocytosis, significantly increased ROS, malondialdehyde and nitric oxide, and declined antioxidant defenses in the heart and lung of rats. In addition, MSNs induced histological alterations in the heart and lung of rats. In conclusion, our results demonstrated that MSNs induce cardiotoxicity and pulmonary toxicity via excessive generation of ROS, suppressed antioxidants, inflammation and histological alterations. Further investigations are recommended to understand the molecular mechanism underlying the toxic effects of MSNs and to improve the performance of nanomedicine.

A self-nanoemulsifying drug delivery system (SNEDDS) was developed as a novel route to enhance the efficacy of docetaxel lipophilic drug. SNEDDS comprised ethyl oleate, Tween 80 and poly(ethylene glycol) 600, as oil, surfactant and co-surfactant, and formed stabilized monodispersed oil nanodroplets upon dilution in water. SNEDDS represented encapsulation efficiency and loading capacity of 21.4 and 52.7%, respectively. The docetaxel release profile from the drug-loaded SNEDDS was recorded, its effectiveness against MCF-7 cell line was investigated, and an IC50 value of 0.98 ± 0.05 μg mL-1 was attained. The drug-loaded SNEDDS was administrated in rats, and the pharmacokinetic parameters of maximum concentration of 22.2 ± 0.8 μg mL-1, time to attain this maximum concentration of 230 min, and area under the curve of 1.71 ± 0.18 μg min mL-1 were obtained. The developed SNEDDS formulation can be represented as an alternative to docetaxel administration.

We evaluated the influence of nanoencapsulation of the flavonoid Dihydromyricetin (DMY) in reducing the genotoxicity and cytotoxicity induced by cationic nanocapsules. Assays were conducted in order to evaluate the potential of protein corona formation, cytotoxicity, genotoxicity and the antioxidant capacity. Nanocapsules containing DMY (NC-DMY) and free DMY (DMY-F) did not demonstrate cytotoxicity and genotoxicity. However, Eudragit RS100® nanocapsules (NC-E) increased cytotoxicity and DNA damage formation. NC-DMY and NC-E presented high interaction with the DNA in vitro, suggesting DNA sequestration. These results indicate that nanoencapsulated DMY does not induce cytotoxicity or genotoxicity, and demonstrates high antioxidant capacity. This antioxidant capacity is probably associated with DMY, and occurs due to its ability to avoid the formation of free radicals, thus preventing the toxicity caused by the nanostructure with the cationic polymer Eudragit RS100®. Therefore, NC-DMY can be considered an important formulation with significant antioxidant potential to be exploited by nanomedicine.

Cancer nanomedicine using nanoparticle-based delivery systems has shown outstanding promise in recent decades for improving anticancer treatment. However, limited targeting efficiency, low drug loading efficiency and innate toxicity of nanoparticles have caused severe problems, leaving only a few available in the clinic. Here, we newly developed carrier-free nanoparticles of cathepsin B-cleavable peptide (Phe-Arg-Arg-Gly; FRRG)-conjugated doxorubicin (DOX) prodrug (FRRG-DOX) that formed a stable nanoparticle structure with an average diameter of 213 nm in aqueous condition. The carrier-free nanoparticles of FRRG-DOX induced cytotoxicity against cathepsin B-overexpressed tumor cells whereas the toxicity was minimized in normal cells. In particular, the FRRG-DOX nanoparticles showed the successful tumor-targeting ability and enhanced therapeutic efficiency in human colon adenocarcinoma (HT-29) tumor-bearing mice via enhanced permeation and retention (EPR) effect. Furthermore, FRRG-DOX nanoparticles did not present any severe toxicity, such as non-specific cell death and cardiac toxicity, in normal tissues due to minimal expression of cathepsin B. This carrier-free nanoparticles of FRRG-DOX can solve the unavoidable problems of current nanomedicine, such as lower targeting efficiency, toxicity of nanoparticles themselves, and difficulty in mass production that are fatally caused by natural and synthetic nano-sized carriers.

Pancreatic cancer is a highly lethal malignancy. Lack of early diagnostic markers makes timely detection of pancreatic cancer a highly challenging endeavor. Exosomes have emerged as information-rich cancer specific biomarkers. However, characterization of tumor-specific exosomes has been challenging. This study investigated the proof-of principal that exosomes could be used for the detection of pancreatic cancer. Label-free analysis of exosomes purified from normal and pancreatic cancer cell lines was performed using surface enhanced Raman Spectroscopy (SERS) and principal component differential function analysis (PC-DFA), to identify tumor-specific spectral signatures. This method differentiated exosomes originating from pancreatic cancer or normal pancreatic epithelial cell lines with 90% accuracy. The cell line trained PC-DFA algorithm was next applied to SERS spectra of serum-purified exosomes. This method exhibited up to 87% and 90% predictive accuracy for HC and EPC individual samples, respectively. Overall, our study identify utility of SERS spectral signature for deciphering exosomal surface signature.

Endothelial dysfunction is recognized as a critical condition in the development of cardiovascular disorders. This multifactorial process involves changes in the biochemical and mechanical properties of endothelial cells leading to disturbed release of vasoprotective mediators. Hypercholesterolemia and increased stiffness of the endothelial cortex are independently shown to result in reduced release of nitric oxide and thus endothelial dysfunction. However, direct evidence linking these parameters to each other is missing. Here, a novel method combining Raman spectroscopy for biochemical analysis and Atomic Force Microscopy (AFM) for analyzing the endothelial nanomechanics was established. Using this dual approach, the same areas of native ex vivo aortas were investigated, either derived from mice with endothelial dysfunction (ApoE/LDLR-/-) or wild type mice. In particular an increased intracellular lipid content and elevated cortical stiffness/elasticity was shown in ApoE/LDLR-/- aortas, demonstrating a direct link between endothelial dysfunction, the biochemical composition and the nanomechanical properties of endothelial cells.

Prodrug strategies that facilitate localized and controlled activity of small-molecule therapeutics can reduce systemic exposure and improve pharmacokinetics, yet limitations in activation chemistry have made it difficult to assign tunable multifunctionality to prodrugs. Here, we present the design and application of a modular small-molecule caging strategy that couples bioorthogonal cleavage with a self-immolative linker and an aliphatic anchor. This strategy leverages recently discovered in vivo catalysis by a nanoencapsulated palladium compound (Pd-NP), which mediates alloxylcarbamate cleavage and triggers release of the activated drug. The aliphatic anchor enables >90% nanoencapsulation efficiency of the prodrug, while also allowing >104-fold increased cytotoxicity upon prodrug activation. We apply the strategy to a prodrug formulation of monomethyl auristatin E (MMAE), demonstrating its ability to target microtubules and kill cancer cells only after selective activation by Pd-NP. Computational pharmacokinetic modeling provides a mechanistic basis for the observation that the nanotherapeutic prodrug strategy can lead to more selective activation in the tumor, yet in a manner that is more sensitive to variable enhanced permeability and retention (EPR) effects. Combination treatment with the nanoencapsulated MMAE prodrug and Pd-NP safely blocks tumor growth, especially when combined with a local radiation therapy regimen that is known to improve EPR effects, and represents a conceptual step forward in prodrug design.

In-depth understanding of the biophysicochemical interactions at the nano-bio interface is important for basic cell biology and applications in nanomedicine and nanobiosensors. Here, the extracellular surface potential and topography changes of live cell membranes interacting with polymeric nanomaterials using a scanning ion conductance microscopy-based potential imaging technique are investigated. Two structurally similar amphiphilic conjugated polymer nanoparticles (CPNs) containing different functional groups (i.e., primary amine versus guanidine) are used to study incubation time and functional group-dependent extracellular surface potential and topographic changes. Transmembrane pores, which induce significant changes in potential, only appear transiently in the live cell membranes during the initial interactions. The cells are able to self-repair the damaged membrane and become resilient to prolonged CPN exposure. This study provides an important observation on how the cells interact with and respond to extracellular polymeric nanomaterials at the early stage. This study also demonstrates that extracellular surface potential imaging can provide a new insight to help understand the complicated interactions at the nano-bio interface and the following cellular responses.