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Bovine serum albumin (BSA) hydrogels are non-immunogenic, low-cost, biocompatible, and biodegradable. In order to avoid toxic cross-linking agents, gellan was oxidized with NaIO4 to obtain new functional groups like dialdehydes for protein-based hydrogel cross-linking. The formed dialdehyde groups were highlighted with FT-IR and NMR spectroscopy. This paper aims to investigate hydrogel films for biomedical applications obtained by cross-linking BSA with oxidized gellan (OxG) containing immobilized β-cyclodextrin–curcumin inclusion complex (β-CD–Curc) The β-CD–Curc improved the bioavailability and solubility of Curc and was prepared at a molar ratio of 2:1. The film's structure and morphology were evaluated using FT-IR spectroscopy and SEM. The swelling degree (Q%) values of hydrogel films depend on hydrophilicity and pH, with higher values at pH = 7.4. Additionally, the conversion index of -NH2 groups into Schiff bases increases with an increase in OxG amount. The polymeric matrix provides protection for Curc, is non-cytotoxic, and enhances antioxidant activity. At pH = 5.5, the skin permeability and release efficiency of encapsulated curcumin were higher than at pH = 7.4 because of the interaction of free aldehyde and carboxylic groups from hydrogels with amine groups from proteins present in the skin membrane, resulting in a better film adhesion and more efficient curcumin release. [ABSTRACT FROM AUTHOR]

Glioblastoma multiforme (GBM) is a highly aggressive malignant tumor, and the most prevalent primary malignant tumor affecting the brain and central nervous system. Recent research indicates that the genetic profile of GBM makes it resistant to drugs and radiation. However, the main obstacle in treating GBM is transporting drugs through the blood–brain barrier (BBB). Albumin is a versatile biomaterial for the synthesis of nanoparticles. The efficiency of albumin-based delivery systems is determined by their ability to improve tumor targeting and accumulation. In this review, we will discuss the prevalence of human glioblastoma and the currently adopted treatment, as well as the structure and some essential functions of the BBB, to transport drugs through this barrier. We will also mention some aspects related to the blood–tumor brain barrier (BTBB) that lead to poor treatment efficacy. The properties and structure of serum albumin were highlighted, such as its role in targeting brain tumors, as well as the progress made until now regarding the techniques for obtaining albumin nanoparticles and their functionalization, in order to overcome the BBB and treat cancer, especially human glioblastoma. The albumin drug delivery nanosystems mentioned in this paper have improved properties and can overcome the BBB to target brain tumors. [ABSTRACT FROM AUTHOR]

Amylase is an enzyme used to hydrolyze starch in order to obtain different products that are mainly used in the food industry. The results reported in this article refer to the immobilization of α-amylase in gellan hydrogel particles ionically cross-linked with Mg2+ ions. The obtained hydrogel particles were characterized physicochemically and morphologically. Their enzymatic activity was tested using starch as a substrate in several hydrolytic cycles. The results showed that the properties of the particles are influenced by the degree of cross-linking and the amount of immobilized α-amylase enzyme. The temperature and pH at which the immobilized enzyme activity is maximum were T = 60 °C and pH = 5.6. The enzymatic activity and affinity of the enzyme to the substrate depend on the particle type, and this decreases for particles with a higher cross-linking degree owing to the slow diffusion of the enzyme molecules inside the polymer's network. By immobilization, α-amylase is protected from environmental factors, and the obtained particles can be quickly recovered from the hydrolysis medium, thus being able to be reused in repeated hydrolytic cycles (at least 11 cycles) without a substantial decrease in enzymatic activity. Moreover, α-amylase immobilized in gellan particles can be reactivated via treatment with a more acidic medium. [ABSTRACT FROM AUTHOR]

ABSTRACT The micellization of three tailor-made triblock copolymers, such as PB100-P2VP100-PEO104, PB185-P2VP108-PEO154, and PB37-P2VP115-PEO241, having similar total molecular weights and constant poly(2-vinylpyridine) (P2VP) sequence lengths, was investigated as a function of pH and sodium dodecyl sulfate (SDS) concentration. At pH 7 the formation of intermicellar aggregates was observed, especially for copolymers of low poly(ethylene oxide) (PEO) content. A pH decrease from 7 to 3 leads to a particle size increase due to the electrostatic repulsion of the protonated P2VP chains. The influence of the PEO sequence length was also observed for zeta potential values. At pH 3, in the absence of SDS, core-shell-corona micelles are formed whereas in the presence of small amount of SDS (degree of neutralization DN = 0%-50%), a complex is formed between SDS and the protonated P2VP which leads to the shrinkage of the shell and thus to a decrease of the micellar sizes. For higher DN values, the micellar sizes increase due to the formation of large agglomerates and a transition occurs from a monomodal to a bimodal size distribution. Furthermore, it turned out that secondary aggregation, such as intermicellar aggregation, can completely be avoided if the degree of polymerization (DPn) of the water-soluble block is significantly higher than the DPn of the water-insoluble sequence. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45313. [ABSTRACT FROM AUTHOR]

Curcumin has antibacterial and anti-inflammatory activity, and in topical applications, it was successfully used to treat rashes and skin infections. The hydrogel films based on gellan/albumin (BSA) with β-cyclodextrin/curcumin inclusion complex incorporated were prepared at pH = 7.8 by ionic cross-linking with magnesium acetate, to improve the curcumin stability and bioavailability. The films thus obtained were polyelectrolyte complexed with 1% pectin solution pH=3.5. BSA was used in this study due to its therapeutic effects that can lead to improved biocompatibility of the hydrogel film. The films were characterized by swelling degree, SEM, FT-IR, TGA, mechanical tests, cytoxicity, and the antioxidant activity was evaluated. The release kinetics of curcumin from films was performed in two different media: at pH=5.5 and pH=7.4, and a higher release efficiency was found at pH=7.4. The results confirm the biopolymer matrix protective role and the possibility of using the hydrogel obtained in biomedical applications. [ABSTRACT FROM AUTHOR]

The chitosan used was of medium molecular weight, with a 75% deacetylation degree. Crosslinking to obtain hydrogels was performed with partially oxidized carboxymethyl cellulose (CMC-Ox) with NaIO4, to form aldehyde groups by cleaving the C2-C3 bond and the oxidation degree of 45%. The films were obtained by cross-linking as a result of the reaction between the chitosan amine groups with CMC-Ox dialdehyde groups, working at different molar ratios -NH2/-CH=O. The amine groups amount that didn't participate at cross-linking (determined by the ninhydrin test) and the swelling degree value in different mediums decreases as the CMC-Ox amount increases as a result of cross-linking degree. The CMC-Ox and hydrogel films were characterized by SEM, FT-IR and NMR spectroscopy. CMC-Ox could constitute an appropriate cross-linking agent for chitosan having the advantage to avoid the use of another covalent cross-linker, usually toxic and the hydrogel obtained could be used as support for curcumin immobilization. [ABSTRACT FROM AUTHOR]

Adding carbonyl groups into the hydrogel matrix improves the stability and biocompatibility of the hydrogels, making them suitable for different biomedical applications. In this review article, we will discuss the use of hydrogels based on polysaccharides modified by oxidation, with particular attention paid to the introduction of carbonyl groups. These hydrogels have been developed for several applications in tissue engineering, drug delivery, and wound healing. The review article discusses the mechanism by which oxidized polysaccharides can introduce carbonyl groups, leading to the development of hydrogels through cross-linking with proteins. These hydrogels have tunable mechanical properties and improved biocompatibility. Hydrogels have dynamic properties that make them promising biomaterials for various biomedical applications. This paper comprehensively analyzes hydrogels based on cross-linked proteins with carbonyl groups derived from oxidized polysaccharides, including microparticles, nanoparticles, and films. The applications of these hydrogels in tissue engineering, drug delivery, and wound healing are also discussed.