Liposome-Hydrogel Composites for Controlled Drug Delivery Applications.

Various controlled delivery systems (CDSs) have been developed to overcome the shortcomings of traditional drug formulations (tablets, capsules, syrups, ointments, etc.). Among innovative CDSs, hydrogels and liposomes have shown great promise for clinical applications thanks to their cost-effectiveness, well-known chemistry and synthetic feasibility, biodegradability, biocompatibility and responsiveness to external stimuli. To date, several liposomal- and hydrogel-based products have been approved to treat cancer, as well as fungal and viral infections, hence the integration of liposomes into hydrogels has attracted increasing attention because of the benefit from both of them into a single platform, resulting in a multifunctional drug formulation, which is essential to develop efficient CDSs. This short review aims to present an updated report on the advancements of liposome-hydrogel systems for drug delivery purposes.

Preparation of Peptide-Based Magnetogels for Removing Organic Dyes from Water.

Water pollution by organic dyes represents a major health and environmental issue. Despite the fact that peptide-based hydrogels are considered to be optimal absorbents for removing such contaminants, hydrogel systems often suffer from a lack of mechanical stability and complex recovery. Recently, we developed an enzymatic approach for the preparation of a new peptide-based magnetogel containing polyacrylic acid-modified γ-Fe2O3 nanoparticles (γ-Fe2O3NPs) that showed the promising ability to remove cationic metal ions from aqueous phases. In the present work, we tested the ability of the magnetogel formulation to remove three model organic dyes: methyl orange, methylene blue, and rhodamine 6G. Three different hydrogel-based systems were studied, including: (1) Fmoc-Phe3 hydrogel; (2) γ-Fe2O3NPs dispersed in the peptide-based gel (Fe2O3NPs@gel); and (3) Fe2O3NPs@gel with the application of a magnetic field. The removal efficiencies of such adsorbents were evaluated using two different experimental set-ups, by placing the hydrogel sample inside cuvettes or, alternatively, by placing them inside syringes. The obtained peptide magnetogel formulation could represent a valuable and environmentally friendly alternative to currently employed adsorbents.

Peptide-Hydrogel Nanocomposites for Anti-Cancer Drug Delivery.

Cancer is the second leading cause of death globally, but conventional anticancer drugs have side effects, mainly due to their non-specific distribution in the body in both cancerous and healthy cells. To address this relevant issue and improve the efficiency of anticancer drugs, increasing attention is being devoted to hydrogel drug-delivery systems for different kinds of cancer treatment due to their high biocompatibility and stability, low side effects, and ease of modifications. To improve the therapeutic efficiency and provide multi-functionality, different types of nanoparticles (NPs) can be incorporated within the hydrogels to form smart hydrogel nanocomposites, benefiting the advantages of both counterparts and suitable for advanced anticancer applications. Despite many papers on non-peptide hydrogel nanocomposites, there is limited knowledge about peptide-based nanocomposites, specifically in anti-cancer drug delivery. The aim of this short but comprehensive review is, therefore, to focus attention on the synergies resulting from the combination of NPs with peptide-based hydrogels. This review, which includes a survey of recent advances in this kind of material, does not aim to be an exhaustive review of hydrogel technology, but it instead highlights recent noteworthy publications and discusses novel perspectives to provide valuable insights into the promising synergic combination of peptide hydrogels and NPs for the design of novel anticancer drug delivery systems.

Surface modification of TiO2 nanoparticles with organic molecules and their biological applications.

In recent years, titanium(IV) dioxide nanoparticles (TiO2NPs) have shown promising potential in various biological applications such as antimicrobials, drug delivery, photodynamic therapy, biosensors, and tissue engineering. For employing TiO2NPs in these fields, their nanosurface must be coated or conjugated with organic and/or inorganic agents. This modification can improve their stability, photochemical properties, biocompatibility, and even surface area for further conjugation with other molecules such as drugs, targeting molecules, polymers, etc. This review describes the organic-based modification of TiO2NPs and their potential applications in the mentioned biological fields. In the first part of this review, around 75 recent publications (2017-2022) are mentioned on the common TiO2NP modifiers including organosilanes, polymers, small molecules, and hydrogels, which improve the photochemical features of TiO2NPs. In the second part of this review, we presented 149 recent papers (2020-2022) about the use of modified TiO2NPs in biological applications, in which specific bioactive modifiers are introduced in this part with their advantages. In this review, the following information is presented: (1) the common organic modifiers for TiO2NPs, (2) biologically important modifiers and their benefits, and (3) recent publications on biological studies on the modified TiO2NPs with their achievements. This review shows the paramount significance of the organic-based modification of TiO2NPs to enhance their biological effectiveness, paving the way toward the development of advanced TiO2-based nanomaterials in nanomedicine.

Self-Assembling Peptide-Based Magnetogels for the Removal of Heavy Metals from Water.

In this study, we present the synthesis of a novel peptide-based magnetogel obtained through the encapsulation of γ-Fe2O3-polyacrylic acid (PAA) nanoparticles (γ-Fe2O3NPs) into a hydrogel matrix, used for enhancing the ability of the hydrogel to remove Cr(III), Co(II), and Ni(II) pollutants from water. Fmoc-Phe (Fluorenylmethoxycarbonyl-Phenylalanine) and diphenylalanine (Phe2) were used as starting reagents for the hydrogelator (Fmoc-Phe3) synthesis via an enzymatic method. The PAA-coated magnetic nanoparticles were synthesized in a separate step, using the co-precipitation method, and encapsulated into the peptide-based hydrogel. The resulting organic/inorganic hybrid system (γ-Fe2O3NPs-peptide) was characterized with different techniques, including FT-IR, Raman, UV-Vis, DLS, ζ-potential, XPS, FESEM-EDS, swelling ability tests, and rheology. Regarding the application in heavy metals removal from aqueous solutions, the behavior of the obtained magnetogel was compared to its precursors and the effect of the magnetic field was assessed. Four different systems were studied for the separation of heavy metal ions from aqueous solutions, including (1) γ-Fe2O3NPs stabilized with PAA, (γ-Fe2O3NPs); (2) Fmoc-Phe3 hydrogel (HG); (3) γ-Fe2O3NPs embedded in peptide magnetogel (γ-Fe2O3NPs@HG); and (4) γ-Fe2O3NPs@HG in the presence of an external magnetic field. To quantify the removal efficiency of these four model systems, the UV-Vis technique was employed as a fast, cheap, and versatile method. The results demonstrate that both Fmoc-Phe3 hydrogel and γ-Fe2O3NPs peptide magnetogel can efficiently remove all the tested pollutants from water. Interestingly, due to the presence of magnetic γ-Fe2O3NPs inside the hydrogel, the removal efficiency can be enhanced by applying an external magnetic field. The proposed magnetogel represents a smart multifunctional nanosystem with improved absorption efficiency and synergic effect upon applying an external magnetic field. These results are promising for potential environmental applications of γ-Fe2O3NPs-peptide magnetogels to the removal of pollutants from aqueous media.

Biosynthesis of Peptide Hydrogel-Titania Nanoparticle Composites with Antibacterial Properties.

The photoantibacterial properties of titania nanoparticles (TiO2NPs) are attracting much interest, but the separation of their suspension limits their application. In this study, the encapsulation of commercial TiO2NPs within self-assembling tripeptide hydrogels to form hgel-TiO2NP composites with significant photoantibacterial properties is reported. The Fmoc-Phe3 hydrogelator was synthesized via an enzymatic method. The resulting composite was characterized with DLS, ζ-potential, SAXS, FESEM-EDS and rheological measurements. Two different concentrations of TiO2NPs were used. The results showed that, by increasing the TiO2NP quantity from 5 to 10 mg, the value of the elastic modulus doubled, while the swelling ratio decreased from 63.6 to 45.5%. The antimicrobial efficacy of hgel-TiO2NPs was tested against a laboratory Staphylococcus aureus (S. aureus) strain and two methicillin-resistant S. aureus (MRSA) clinical isolates. Results highlighted a concentration-dependent superior antibacterial activity of hgel-TiO2NPs over TiO2NPs in the dark and after UV photoactivation. Notably, UV light exposure substantially increased the biocidal action of hgel-TiO2NPs compared to TiO2NPs. Surprisingly, in the absence of UV light, both composites significantly increased S. aureus growth relative to control groups. These findings support the role of hgel-TiO2NPs as promising biocidal agents in clinical and sanitation contexts. However, they also signal concerns about TiO2NP exposure influencing S. aureus virulence.