LAFeBS, alive, kicking, and growing: the story continues .

This Commentary describes a call for contributions to an upcoming Special Issue (SI) of Biophysical Reviews on the Latin American Federation of Biophysical Societies (LAFeBS). It details the reason for the SI, the SI Editors' contact information, and the relevant submission details for those wishing to contribute a review manuscript.

Rheological and Viscoelastic Analysis of Hybrid Formulations for Topical Application.

The rheological and viscoelastic properties of hybrid formulations composed of vehicles designed for cutaneous topical application and loaded with ultradeformable liposomes (UDL) were assessed. UDL were selected for their established ability to transport both lipophilic and hydrophilic compounds through the skin, and are applicable in pharmaceuticals and cosmetics. Formulations underwent flow analysis and were fitted to the Herschel-Bulkley model due to their prevalent non-Newtonian behavior in most cases. Linear viscoelastic regions (LVR) were identified, and G' and G″ moduli were determined via frequency sweep steps, considering the impact of temperature and aging. The formulations exhibited non-Newtonian behavior with pseudoplastic traits in most cases, with UDL incorporation inducing rheological changes. LVR and frequency sweep tests indicated predominantly elastic solid behavior, with G' higher than G″, at different temperatures and post-production times. Tan δ values also illustrated a predominant solid-like behavior over liquid. This study provides pivotal insights into the rheological and viscoelastic features of topical formulations, emphasizing the crucial role of meticulous vehicle and formulation selection when incorporating UDL or analogous liposomal drug delivery systems.

Fifty years of biophysics in Argentina.

In 1972, a group of young Argentinean scientists nucleated in the so-called Membrane Club constituted the Biophysical Society of Argentina (SAB). Over the years, this Society has grown and embraced new areas of research and emerging technologies. In this commentary, we provide an overview of the early stages of biophysics development in Argentina and highlight some of the notable achievements made during the past five decades. The SAB Annual Meetings have been a platform for intense scientific discussions, and the Society has fostered numerous international connections, becoming a hallmark of SAB activities over these 50 years. Initially centered on membrane biophysics, SAB focus has since expanded to encompass diverse fields such as molecular, cellular, and systems biophysics.

Rheological, Physical, and Spectroscopical Characterization of Gamma-Irradiated Albumin Nanoparticles Loaded with Anthocyanin.

Anthocyanins are the main active compounds in blueberry. However, they have poor oxidation stability. If anthocyanins are encapsulated in protein nanoparticles, their oxidation resistance could be increased as a result of the slowing down of the oxidation process. This work describes the advantages of using a γ-irradiated bovine serum albumin nanoparticle bound to anthocyanins. The interaction was characterized biophysically, mainly by rheology. By computational calculation and simulation based on model nanoparticles, we estimated the number of molecules forming the albumin nanoparticles, which allowed us to infer the ratio of anthocyanin/nanoparticles. Measurements by UV-vis spectroscopy, FTIR spectroscopy, fluorescence spectroscopy, dynamic light scattering (DLS), ζ potential, electron transmission microscopy, and rheology at room (25 °C) and physiological (37 °C) temperatures were performed. The spectroscopy measurements allowed identifying additional hydrophobic sites created during the irradiation process of the nanoparticle. On the basis of the rheological studies, it was observed that the BSA-NP trend is a Newtonian flow behavior type for all the temperatures selected, and there is a direct correlation between dynamic viscosity and temperature values. Furthermore, when anthocyanins are added, the system increases its resistance to the flow as reflected in the morphological changes observed by TEM, thus confirming the relationship between viscosity values and aggregate formation.

Biophysical Reviews special issue call: LAFeBS-highlighting biophysics in Latin America.

This Commentary describes a call for contributions to an upcoming Special Issue (SI) of Biophysical Reviews on the Latin American Federation of Biophysical Societies (LAFeBS). It details the reason for the SI, the SI Editors contact information and the relevant submission details for those wishing to contribute.

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.

Lipopolymers and lipids from lung surfactants in association with N-acetyl-l-cysteine: Characterization and cytotoxicity.

In the present work, we obtained polymeric diacetylene liposomes that can associate N-Acetyl-l-Cysteine (NAC), a broad spectrum mucolytic. The reason for studying these formulations is that they could be applied in the future as NAC delivery systems, with a possible dose reduction but maintaining its effect. Liposomes used herein are obtained by a photopolymerization reaction, thus gaining stability and rigidity. Lipids belonging to lung surfactant were added in different ratios to the formulations in order to maximize its possible interaction with the lung tissue. Because of lipopolymer stability, the oral or nasal route could be appropriated. This formulation could efficiently transport NAC to exert its mucolytic activity and help in diseases such as cystic fibrosis, which has abnormal mucus production. Also, this type of treatment could be useful in other types of diseases, interacting with the mucus layer and making the lung tissue more permeable to other therapies. Formulations so obtained presented high levels of polymerization. Also, they present small hollow fibers structures with a high number of polymeric units. These types of arrangements could present advantages in the field of drug delivery, giving the possibility of a controlled release. Lipopolymers with lipids from lung surfactant associated with NAC are promising complexes in order to treat not only respiratory illnesses. The stability of the formulation would allow its inoculation through other routes such as the oral one, helping the reposition of NAC as an antioxidant drug. Finally, these formulations are non-toxic and easy to produce.

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.

Combined Therapy for Alzheimer's Disease: Tacrine and PAMAM Dendrimers Co-Administration Reduces the Side Effects of the Drug without Modifying its Activity.

Alzheimer's disease has become a public health priority, so an investigation of new therapies is required. Tacrine (TAC) was licensed for treatments; however, its oral administration caused hepatotoxicity, so it is essential to reduce the side effects. PAMAM dendrimer generation 4.0 and 4.5 (DG4.0 and DG4.5) can be used as drug delivery systems and as nanodrugs per se. Our work aims to propose a combined therapy based on TAC and PAMAM dendrimer co-administration. TAC and dendrimer interactions were studied by in vitro drug release, drug stability, and FTIR. The toxicity profile of co-administration was evaluated in human red blood cells, in Neuro-2a cell culture, and in zebrafish larvae. Also, the anti-acetylcholinesterase activity was studied in cell culture. It was possible to obtain DG4.0-TAC and DG4.5-TAC suspensions, without reducing the drug solubility and stability. FTIR and in vitro release studies confirmed that interaction between TAC and DG4.5 was of the electrostatic type. No toxicity effects on human red blood cells were observed, whereas the co-administration with DG4.5 reduced cytotoxicity of TAC on the Neuro-2a cell line. Moreover, in vivo co-administration of both DG4.0-TAC and DG4.5-TAC reduced the morphological and hepatotoxic effects of TAC in zebrafish larvae. The reduction of TAC toxicity was not accompanied by a reduction in its activity since the anti-acetylcholinesterase activity remains when it is co-administrated with dendrimers. In conclusion, the co-administration of TAC with both DG4.0 and DG4.5 is a novel therapy since it was less-toxic, was more biocompatible, and has the same effectiveness than the free drug. Graphical abstract.

Media interaction and stability of a gamma irradiated albumin nanoparticle.

Protein nanoparticle designing at the nanoscale is challenging because of protein vulnerability to chemical and physical degradation during processing and biodistribution. We present a crosslinked gamma irradiated albumin-based nanoparticle as a potential drug delivery system. The focus was set on the study of the nanoparticle under adverse experimental conditions: different pH values, SDS, tween 80 and urea. The albumin-based nanoparticle was also tested against time stabilityand ionic strength solutions Regarding its stability against pH, the nanoparticle showed similarity to the behaviour of albumin, whilst the stability of the nanoparticle improved in urea and Tween 80. The nanoparticle was stable for 15 days, and presented no protein degradation in solutions up to 2 M salt concentration. Moreover, it presented a better and controlled drug release at slightly acidic pH values than at physiological pH. Results highlight the potentiality of the nanoparticle due to its biophysical properties as a drug delivery system. The hydrophobic character of the albumin molecules changes when they are in aggregating conditions, and treated with gamma irradiation. Our results reveal that stability of the nanoparticle can result from a competition between short-range attraction and long-range repulsion. They provide a framework for understanding the stability and functioning of nanoparticles. Most interesting, the results here serve as a platform for improving the design of the nanoparticle for future in vivo testing.

Effect of structure in ionised albumin based nanoparticle: Characterisation, Emodin interaction, and in vitro cytotoxicity.

A γ-irradiated bovine albumin serum-based nanoparticle was characterised structurally, and functionally. The nanoparticle was characterised by A.F.M., D.L.S, zeta potential, T.E.M., gel-electrophoresis, and spectroscopy. We studied the stability of the nanoparticle at different pH values and against time, by fluorescence spectroscopy following the changes in the tryptophan environment in the nanoparticle. The nanoparticle was also functionalized with Folic Acid, its function as a nanovehicle was evaluated through its interaction with the hydrophobic drug Emodin. The binding and kinetic properties of the obtained complex were evaluated by biophysical methods as well as its toxicity in tumor cells. According to its biophysics, the nanoparticle is a spherical nanosized vehicle with a hydrodynamic diameter of 70 nm. Data obtained describe the nanoparticle as nontoxic for cancer cell lines. When combined with Emodin, the nanoparticle proved to be more active on MCF-7 cancer cell lines than the nanoparticle without Emodin. Significantly, the albumin aggregate preserves the main activity-function of albumin and improved characteristics as an excellent carrier of molecules. More than carrier properties, the nanoparticle alone induced an immune response in macrophages which may be advantageous in vaccine and cancer therapy formulation.

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.

Folic acid magnetic nanotheranostics for delivering doxorubicin: Toxicological and biocompatibility studies on Zebrafish embryo and larvae.

Doxorubicin (DOXO) is a chemotherapeutic agent widely used for the treatment of solid tumors and hematologic malignancies in both adults and children. However, DOXO causes short- and long-term cardiotoxicity and others undesirable side effects, such as nephrotoxicity and neurotoxicity. Magnetic nanoparticles (MNPs) allow the delivery of drugs specifically to target place, employing an external magnet. Moreover, they may act as contrast agents in MRI providing information on the diagnostic of diverse pathologies. In this way, two functions may be combined in a unique nanosystem known as theranostic. Also, the MNPs can be modified with folic acid (MNPs@FA) to increase the uptake by cancer cells that overexpress the FA receptors. In previous works, our collaborators obtained and characterized MNPs, MNPs@FA, and MNPs@FA@DOXO. It is essential to study the biosafety of nanotheranostic, and there is no published study of Fe3O4 nanoparticles developmental toxicity. Because of that, this work aimed to study the in vivo toxicity and biocompatibility of DOXO, MNPs@FA, and MNPs@FA@DOXO using zebrafish embryo and larvae as an animal model. Viability, developmental toxicity, changes in spontaneous movement (neurotoxicity), changes in cardiac rhythm (cardiotoxicity), and efficiency of DOXO-uptake were studied. While the 48-h treatment with 50 µg/mL of DOXO resulted in a 30% larvae death and the development of significant morphological abnormalities, the treatment with MNPs@FA@DOXO and MNPs@FA did not reduce the viability and did not cause developmental abnormalities. Besides, the MNPs@FA@DOXO reduced the cardiotoxicity and promoted a more rapid and significant uptake of DOXO by zebrafish larvae.

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.

Toward biomedical application of amino-functionalized silicon nanoparticles.

Silicon blue-emitting nanoparticles (NPs) are promising effectors for photodynamic therapy and radiotherapy, because of their production of reactive oxygen species (ROS) upon irradiation. RESULTS: Amino-functionalized silicon NPs (NH2SiNP) were intrinsically nontoxic below 100 µg/ml in vitro (on two tumor cell lines) and in vivo (zebrafish larvae and embryos). NH2SiNP showed a moderate effect as a photosensitizer for photodynamic therapy and reduced ROS generation in radiotherapy, which could be indicative of a ROS scavenging effect. Encapsulation of NH2SiNP into ultradeformable liposomes improved their skin penetration after topical application, reaching the viable epidermis where neoplastic events occur. CONCLUSION: Subsequent derivatizations after amino-functionalization and incorporation to nanodrug delivery systems could expand the spectrum of the biomedical application of these kind of silicon NPs.

Dibucaine in Ionic-Gradient Liposomes: Biophysical, Toxicological, and Activity Characterization.

Administration of local anesthetics is one of the most effective pain control techniques for postoperative analgesia. However, anesthetic agents easily diffuse into the injection site, limiting the time of anesthesia. One approach to prolong analgesia is to entrap local anesthetic agents in nanostructured carriers (e.g., liposomes). Here, we report that using an ammonium sulphate gradient was the best strategy to improve the encapsulation (62.6%) of dibucaine (DBC) into liposomes. Light scattering and nanotracking analyses were used to characterize vesicle properties, such as, size, polydispersity, zeta potentials, and number. In vitro kinetic experiments revealed the sustained release of DBC (50% in 7 h) from the liposomes. In addition, in vitro (3T3 cells in culture) and in vivo (zebrafish) toxicity assays revealed that ionic-gradient liposomes were able to reduce DBC cyto/cardiotoxicity and morphological changes in zebrafish larvae. Moreover, the anesthesia time attained after infiltrative administration in mice was longer with encapsulated DBC (27 h) than that with free DBC (11 h), at 320 µM (0.012%), confirming it as a promising long-acting liposome formulation for parenteral drug administration of DBC.

PAMAM dendrimers as a carbamazepine delivery system for neurodegenerative diseases: A biophysical and nanotoxicological characterization.

Carbamazepine (CBZ) is an antiepileptic drug, which also could be used in the treatment of neurodegenerative diseases, such as the Alzheimer's disease. However, its use has been limited due to its low solubility, inefficient pharmacokinetic profiles, and multiple side effects. PAMAM dendrimers, ethylenediamine core, generation 4.0 (amine terminal groups) and 4.5 (carboxylate terminal groups) (DG4.0 and DG4.5 respectively) are polymers that can increase drug solubility through complexation. Thus, the aim of this work was to obtain and characterize complexes between CBZ and dendrimers. Both DG4.0 and DG4.5 allowed the incorporation of ∼20 molecules of CBZ per dendrimer, into their hydrophobic pockets. DG4.0-CBZ and DG4.5-CBZ complexes were found to be stable for 90 days at 37 °C and resistant to a lyophilization process, presenting controlled drug release. Also, the complexes nanotoxicity was tested ex vivo (human red blood cells), in vitro (N2a cell line), and in vivo (zebrafish). No hemolytic effect was observed in the ex vivo model. As regards in vitro toxicity, the DG4.5-CBZ complexes significantly reduced the toxicity caused by the free drug. Moreover, the DG4.5-CBZ did not cause neurotoxicity or cardiotoxicity in zebrafish larvae. In conclusion, a stable and biocompatible drug delivery system based on the DG4.5 capable of complex the CBZ has been developed. This achievement highlights the advantages of using negatively charged dendrimers for nanomedicine.

Skin penetration and UV-damage prevention by nanoberries.

BACKGROUND: Ethanolic extract from blueberry (Vaccinium myrtillus) is rich in anthocyanins and thus exhibits antioxidant activity. On the other hand, ultradeformable liposomes are capable of penetrating to the impermeable barrier of skin. Nanoberries are ultradeformable liposomes carrying blueberry extract. OBJECTIVES: In this study, their capacity to penetrate the stratum corneum and photodamage prevention were tested, with the aim of developing a topical formulation for skin protection from environmental damage. METHODS: Nanoberries were prepared by lipid film resuspension with ethanolic extract from blueberry, followed by sonication and incorporation to a gel. Size, zeta potential, deformability, rheology, and viscoelasticity were determined. Toxicity was assessed in vivo in zebrafish model, while in vitro cytotoxicity assay was performed on HaCaT and HEK-293T cell lines. Skin penetration was evaluated with the Saarbrücken penetration model followed by tape stripping, cryosection, or optical sectioning. UV-damage protection and photoprotection were determined by ad hoc methods with UVA, UVB, and UVC radiation on HaCaT cells. Wound assay was performed on HaCaT cells. RESULTS: Nanoberries of about 100 nm, with differential elastic properties, did penetrate the stratum corneum, with low toxicity. When HaCaT cells were exposed to UV radiation in the presence of nanoberries, their viability was maintained. CONCLUSIONS: Nanoberries could be effective to protect the skin from sun photodamage.

Nano-formulation for topical treatment of precancerous lesions: skin penetration, in vitro, and in vivo toxicological evaluation.

With the aim of improving the topical delivery of the antineoplastic drug 5-fluorouracil (5FU), it was loaded into ultradeformable liposomes composed of soy phosphatidylcholine and sodium cholate (UDL-5FU). The liposome populations had a mean size of 70 nm without significant changes in 56 days, and the ultradeformable formulations were up to 324-fold more elastic than conventional liposomes. The interaction between 5FU and the liposomal membrane was studied by three methods, and also release profile was obtained. UDL-5FU did penetrate the stratum corneum of human skin. At in vitro experiments, the formulation was more toxic on a human melanoma-derived than on a human keratinocyte-derived cell line. Cells captured liposomes by metabolically active processes. In vivo toxicity experiments were carried out in zebrafish (Danio rerio) larvae by studying the swimming activity, morphological changes, and alterations in the heart rate after incubation. UDL-5FU was more toxic than free 5FU. Therefore, this nano-formulation could be useful for topical application in deep skin precancerous lesions with advantages over current treatments. This is the first work that assessed the induction of apoptosis, skin penetration in a Saarbrücken penetration model, and the toxicological effects in vivo of an ultradeformable 5FU-loaded formulation.