Toward biomedical application of amino-functionalized silicon nanoparticles

Safety assessment of different unloaded polymeric nanocapsules in Caenorhabditis elegans

Nano-sized drug delivery systems have been the subject of intense research in recent years because polymeric materials allow the absorption and release of active substances in a controlled manner. Despite the benefits, the safety of nanoparticulate systems is an aspect to be understood, particularly in vivo systems. Caenorhabditis elegans is a very useful alternative model for nanotoxicology and has been recently applied in this field. The aim of this study was to evaluate toxicological endpoints in C. elegans exposed to nanocapsules (NC) prepared with different coatings: polysorbate 80 (NCP80); polyethylene glycol (NCPEG), Eudragit® RS 100 (NCEUD) and chitosan (NCCS). Nanocapsules were prepared by nanoprecipitation method and showed acceptable physico-chemical characterization. Polyethylene glycol nanocapsules and chitosan nanocapsules increased worms lethality in a dose-dependent manner in acute exposure; polysorbate 80 nanocapsules, polyethylene glycol nanocpsules and chitonan nanocapsules also increased lethality following chronic exposure. Chitosan nanocapsules were the most toxic in all exposures, demonstrating toxicity even at low concentrations. Reproduction and body length were not affected by any of the nanocapsules exposures. The expression of superoxide dismutase showed that polysorbate 80 nanocapsules at the highest concentration slightly increased SOD-3::GFP expression. On the other hand, chitosan nanocapsules exposure blunted SOD-3 expression. This work demonstrates the toxicological differences between nanocapsule produced with different coatings and indicates higher safety for the use of eugragit nanocapsule in new formulations for future drug delivery and targeting systems.

Progress on the toxicity of quantum dots to model organism-zebrafish

In vivo toxicological studies are currently necessary to analyze the probable dangers of quantum dots (QDs) to the environment and human safety, due to the fast expansion of QDs in a range of applications. Because of its high fecundity, cost-effectiveness, well-defined developmental phases, and optical transparency, zebrafish has long been considered the "gold standard" for biosafety assessment of chemical substances and pollutants. In this review, the advantages of using zebrafish in QD toxicity assessment were explored. Then, the target organ toxicities such as developmental toxicity, immunotoxicity, cardiovascular toxicity, neurotoxicity, and hepatotoxicity were summarized. The hazardous effects of different QDs, including cadmium-containing QDs like CdTe, CdSe, and CdSe/ZnS, as well as cadmium-free QDs like graphene QDs (GQDs), graphene oxide QDs (GOQDs), and others, were emphasized and described in detail, as well as the underlying mechanisms of QDs generating these effects. Furthermore, general physicochemical parameters determining QD-induced toxicity in zebrafish were introduced, such as chemical composition and surface coating/modification. The limitations and special concerns of using zebrafish in QD toxicity studies were also mentioned. Finally, we predicted that the utilization of high-throughput screening assays and omics, such as transcriptome sequencing, proteomics, and metabolomics will be popular topic in nanotoxicology.

Urine-Microenvironment-Initiated Composite Hydrogel Patch Reconfiguration Propels Scarless Memory Repair and Reinvigoration of the Urethra

The harsh urine microenvironment (UME), as an inherent hurdle, endangers and renders urethral repair unreachable. Innovatively, the unfavorable UME is utilized as the design source to construct a UME-responsive 3D-printed hydrogel patch for realizing scarless memory repair, wherein laser-excited reactive oxygen species (ROS) production and mechanical strength elevation using chemically crosslinked silicon quantum dots are accessible. Intriguingly, the proposed composite scaffolds can respond to Ca²⁺ in urine, cause structure reconfiguration, and repress swelling to further enhance scaffold stiffness. Systematic experiments validate that ROS birth and unexpected stiffness elevation in such UME-responsive scaffolds can realize scarless memory repair of the urethra in vivo. Comprehensive mechanism explorations uncover that the activations of cell proliferation and collagen-related genes (e.g., MMP-1 and COL3A1) and the dampening of fibrosis-related (e.g., TGF-β/Smad) and mechanosensitive genes (e.g., YAP/TAZ) are responsible for the scarless memory repair of such UME-responsive scaffolds via enhancing collagen deposition, recalling mechanical memory, decreasing fibrosis and inflammation, and accelerating angiogenesis. The design rationales (e.g., UME-initiated structure reconfiguration and antiswelling) can serve as an instructive and general approach for urethra repair.

Overcoming barriers by local drug delivery with liposomes

Localized or topical administration of drugs may be considered as a potential approach for overcoming the problems caused by the various biological barriers encountered in drug delivery. The combination of using localized administration routes and delivering drugs in nanoparticulate formulations, such as liposomes, may have additional advantages. Such advantages include prolonged retention of high drug loads at the site of action and controlled release of the drug, ensuring prolonged therapeutic effect; decreased potential for side-effects and toxicity (due to the high topical concentrations of drugs); and increased protection of drugs from possible harsh environments at the site of action. The use of targeted liposomal formulations may further potentiate any acquired therapeutic advantages. In this review we present the most advanced cases of localized delivery of liposomal formulations of drugs, which have been investigated pre-clinically and clinically in the last ten years, together with the reported therapeutic advantages, in each case.

The Topical Nanodelivery of Vismodegib Enhances Its Skin Penetration and Performance In Vitro While Reducing Its Toxicity In Vivo

Vismodegib is a first-in-class inhibitor for advanced basal cell carcinoma treatment. Its daily oral doses present a high distribution volume and several side effects. We evaluated its skin penetration loaded in diverse nanosystems as potential strategies to reduce side effects and drug quantities. Ultradeformable liposomes, ethosomes, colloidal liquid crystals, and dendrimers were able to transport Vismodegib to deep skin layers, while polymeric micelles failed at this. As lipidic systems were the most effective, we assessed the in vitro and in vivo toxicity of Vismodegib-loaded ultradeformable liposomes, apoptosis, and cellular uptake. Vismodegib emerges as a versatile drug that can be loaded in several delivery systems for topical application. These findings may be also useful for the consideration of topical delivery of other drugs with a low water solubility.

Nanoferulic: From a by-product of the beer industry toward the regeneration of the skin

BACKGROUND

Brewers' spent grain (BSG) is one of the most abundant by-products of the beer industry and causes serious environmental problems. Ferulic acid (FA) is an antioxidant with potential cosmeceutical applications. FA was extracted from BSG, developing a method of high extraction performance in order to be encapsulated in ultradeformable liposomes (Nanoferulic, NF).

AIMS

To obtain a product with high added value such as FA, from a residue currently underused, using simple and economical chemical methods. To load FA into a nanosystem designed for the topical route, its encapsulation has the purpose to take profit from its photoprotective, anti-inflammatory, and antioxidant properties in the deep layers of the skin.

METHODS

Ferulic acid was obtained from dried BSG using acid and basic treatments in series. NF was prepared by lipid film resuspension of a solution containing FA obtained from BSG. Size and Z-potential were determined. Cytotoxicity was assessed in vitro. Skin penetration was assessed by NF determination at different skin depths and by confocal microscopy.

RESULTS

The yield of the extraction process was 0.43% on a dry basis. Encapsulation rendered liposomes of around 140 nm with 92% of encapsulation efficiency. No toxicity was observed in all the tested concentrations. Successful results were obtained from the regeneration studies.

CONCLUSIONS

It was possible to develop a nanosystem containing FA, generating a high-value commercial input for the pharmaceutical and cosmeceutical industry. The use of BSG generated in industrial scale would help to reduce the volume of highly polluting waste.

Comparative skin penetration profiles of formulations including ultradeformable liposomes as potential nanocosmeceutical carriers

BACKGROUND

Ultradeformable liposomes are promising carriers for cosmeceutical actives as they can be loaded with molecules of different polarities, and they present unique penetration properties.

AIMS

While those features have already been tested, we wanted to know whether their special penetration properties could be maintained after incorporation in diverse cosmetic vehicles, including commercial products already in the market.

METHODS

Ultradeformable liposomes loaded with a lipophilic and a hydrophilic fluorescent probe were prepared by lipid film resuspension, followed by extrusion and incorporation to different vehicles and commercial products. Penetration was determined in human and pig skin by incubation, with the Saarbrücken penetration model, followed by the recovery of the probes or by fluorescence microscopy.

RESULTS

The incorporation of ultradeformable liposomes to cosmetic vehicles did not alter their penetration in most of the cases for human skin explants. Pig skin penetration presented significant differences compared with human explants.

CONCLUSIONS

Ultradeformable liposomes could be useful as versatile cosmeceutical carriers in final product formulations.

BSA-capped gold nanoclusters as potential theragnostic for skin diseases: Photoactivation, skin penetration, in vitro, and in vivo toxicity

BSA-capped gold nanoclusters are promising theragnostic systems that can be excited to render both fluorescence emission and reactive oxygen species. Although their synthesis and photoluminescence properties are already well described, more accurate information about their use as photosensitizers is required in order to advance towards health applications. In this work, we have obtained BSA-capped gold nanoclusters and characterized their photophysics by different techniques. Singlet oxygen production was detected upon irradiation, which was enough to produce toxicity on two cell lines. Remarkably, an internal energy transfer, probably due to the presence of smaller nanoclusters and the contribution of oxidized residues of BSA in the system, caused fluorescence emission near 640 nm after excitation in the UV range. Additionally, the system was capable of penetrating human skin beyond the stratum corneum, which enhances the potential of these nanoclusters as bifunctional photodynamic therapy effectors and biomarkers with application in a diversity of skin diseases. In the absence of radiation, BSA-capped gold nanoclusters did not cause toxicity in vitro, while their toxic effect on an in vivo model as zebrafish was determined.

Comparative toxicity of PEG and folate-derived blue-emitting silicon nanoparticles: in vitro and in vivo studies

Aim: Amino functionalization is a first step modification aiming to achieve biomedical applications of silicon nanoparticles, for example, for photodynamic therapy or radiotherapy. Nevertheless, toxicity and low quantum yields due to the positive charge of amino groups emerge as a problem that could be solved with subsequent derivatizations. Materials & methods: Folic and PEG-conjugated nanoparticles were obtained from amino-functionalized silicon nanoparticle (NH2SiNP). Cytotoxicity was determined on a tumor cell line at low and high concentrations. Four end points of in vivo toxicity were evaluated on zebrafish (Danio rerio). Results: Folic acid functionalization reduced the cytotoxicity in comparison to amino and PEG-functionalized nanoparticles. In zebrafish, folic functionalization lowered toxicity in general while PEG increased it. Conclusion: Functionalization of NH2SiNP with folic acid reduced the toxic effects in vitro and in vivo. This could be useful for therapeutic applications. PEG functionalization did not lower the toxicity.

Zebrafish (Danio rerio) model as an early stage screening tool to study the biodistribution and toxicity profile of doxorubicin-loaded mixed micelles

Doxorubicin (DOX) hydrochloride is a powerful anthracycline antibiotic used for the treatment of various types of malignancies, particularly ovarian and metastatic breast cancer. However, DOX presents severe side effects, such as hepatotoxicity, nephrotoxicity, dose-limiting myelosuppression, brain damage and cardiotoxicity. A liposomal formulation, Doxil®, was approved by the FDA, which has managed to reduce the number of cardiac events in patients with metastatic breast cancer. However, in comparison to free DOX, Doxil® has not shown significant improvements regarding survival. We have previously designed DOX-loaded mixed micelles (MMDOX) composed of D-α-tocopheryl polyethylene glycol 1000 succinate (TPGS) and Tetronic® T1107. To assess the potential toxic effects of this novel formulation, in this work the zebrafish (Danio rerio) model was used to evaluate its in vivo toxicity and teratogenicity. This study evaluated and compared the effects of DOX exposure from different formulations (free DOX, MMDOX and Doxil®) on the swimming activity, morphological alterations, cardiac rhythm, lethality rate and DOX biodistribution. MMDOX showed lower lethal effects, morphological alterations and neurotoxic effects than the free drug. This study shows the potential of the MMDOX to be an effective DOX-delivery system because it could reduce the side effects.