Self-assembling of poly(aspartic acid) with bovine serum albumin in aqueous solutions

Sodium alginate/N-(Vinylcaprolactam) based supramolecular self-assembled subcutaneously administered in situ formed gels depot of 5-fluorouracil: Rheological analysis, in vitro cytotoxic potential, in vivo bioavailability and safety evaluation

In current study, novel in situ formed injectable self-assembled thermoreversible depot gels based on N-(Vinylcaprolactam) were synthesized with a carbohydrate polymer i.e. sodium alginate in aqueous solution using cold method. The prepared gels preparations were intended to be utilized as 5-FU delivery depot after injectable administration through subcutaneous route. The structural characterization of self-assembled gels samples were studied through FTIR. The thermal properties of newly formed gels complexes were investigated by DSC and TGA. While the morphology of gels were assessed through SEM. The tunable gelation temperatures and phase transition of optimized formulations were confirmed by tube inverting, rheology determination and optical transmittance test. Thermo and pH response was evaluated at different temperatures and in various acidic and basic buffer solutions. In vitro release experiments were conducted using Franz diffusion system to monitor the controlled delivery fashion of gels matrices. Results concluded that depot gels exhibit controlled delivery fashion with maximum release at pH 7.4 and 37 ± 2 °C. The biocompatible nature of blank gels samples was assessed by MTT assay against Vero cell lines and was found safe. While killing ability of 5-FU encapsulated gels was evaluated against HeLa (19 ± 0.22 μg/ml; 23 ± 0.55 μg/ml) and MCF-7 (21 ± 0.06 μg/ml and 22 ± 0.34 μg/ml) cancer cell lines and were found effective to kill cancer cells. Histopathological study showed that gels depot is safe with no harmful effects on major organs. The in vivo bioavailability in rabbits showed controlled release (C_max, 4465.78 ± 1.99 ng/ml) in comparison to free drug (C_max, 4883.73 ± 3.32 ng/ml) administration after subcutaneous injection.

Bio-aerogels: Fabrication, properties and food applications

Traditional inorganic aerogels sustainability, biodegradability, and environmental safety concerns have driven researchers to find their safe green alternatives. Recently, interest in the application of bio-aerogels has rapidly increased in the food industry due to their unique characteristics such as high specific surface area and porosity, ultralow density, tunable pore size and morphology, and superior properties (physicochemical, mechanical, and functional). Bio-aerogels, a special category of highly porous unique materials, fabricated by the sol-gel method followed by drying processes, comprising three-dimensional networks of interconnected biopolymers (e.g., polysaccharides and proteins) with numerous air-filled pores. The production of bio-aerogels begins with the formation of a homogeneously dispersed precursor solution, followed by gelation and wet gel drying procedures by employing special drying techniques including atmospheric-, freeze-, and supercritical drying. Due to their special properties, bio-aerogels have emerged as sustainable biomaterial for many industrial applications, i.e., encapsulation and controlled delivery, active packaging, heavy metals separation, water and air filtration, oleogels, and biosensors. Bio-aerogels are low-cost, biocompatible, and biodegradable sustainable material that can be used in improving the processing, storage, transportation, and bioavailability of food additives, functional ingredients, and bioactive substances for their health benefits with enhanced shelf-life.

Amino acid derived biopolymers: Recent advances and biomedical applications

Over the past few years, amino acids (AA) have emerged as promising biomaterials for the synthesis of functional polymers. Owing to the diversity of functional groups in amino acids, various polymerization methods may be used to make a wide range of well-defined functional amino-acid/peptide-based optically active polymers with varying polymer lengths, compositions, and designs. When incorporated with chirality and self-assembly, they offer a wide range of applications and are particularly appealing in the field of drug delivery, tissue engineering, and biosensing. There are several classes of these polymers that include polyamides (PA), polyesters (PE), poly(ester-amide)s (PEA)s, polyurethanes (PU)s, poly(depsipeptide)s (PDP)s, etc. They offer the ability to control functionality, conjugation, crosslinking, stimuli responsiveness, and tuneable mechanical/thermal properties. In this review, we present the recent advancements in the synthesis strategies for obtaining these amino acid-derived bio-macromolecules, their self-assembly properties, and the wealth of prevalent applications.

Aggregation Behavior of Poly(Acrylic acid-co-Octadecyl Methacrylate) and Bovine Serum Albumin in Aqueous Solutions

Polymer-protein complexing systems have been extensively studied because of their wide application in biomedicine and industry. Here, we studied the aggregation behavior of the hydrophobically associating water-soluble polymer poly(acrylic acid-co-octadecyl methacrylate) [P(AA-co-OMA)] prepared with nonionic surfactant as an emulsifier and bovine serum albumin (BSA) in aqueous solution. We identified the optimal composite conditions of P(AA-co-OMA) and BSA aqueous solution. We measured the zeta potential, dynamic light-scattering particle size, and surface tension of P(AA-co-OMA) and BSA mixed aqueous solution. The results showed that the aggregation behavior between the polymer and BSA relied mainly on the hydrophobic interactions between the molecules. In addition, the best compounding condition was 8 wt.% of P(AA-co-OMA) content. The structure of hydrophobically associating polymer P(AA-co-OMA) and its aggregation with BSA were characterized by Fourier-transform infrared spectroscopy. The infrared spectroscopy results identified the hydrogen bonding behavior of the amino and carboxyl groups between the polymer and BSA. This behavior was also confirmed using thermogravimetric analysis and differential scanning calorimetry. The thermal decomposition temperature and melting temperature of BSA changed before and after it was combined with the polymer. We measured the morphology of the polymer BSA aggregate with 8 % polymer content by transmission electron microscopy. The binding mechanism was investigated, as well.

Self-Assembled Nanocarriers Based on Modified Chitosan for Biomedical Applications: Preparation and Characterization

Protein-polysaccharide systems are of increasing interest as their combined attributes allow for fulfilling a broad range of applications in biomedical and pharmaceutical fields. In this study, the preparation of nanogels based on maleic anhydride chitosan derivatives (MAC) and bovine serum albumin (BSA) was achieved through a self-assembly process performed in aqueous phase. A series of experiments performed by varying the concentrations of MAC and BSA were conducted to find an appropriate mixing ratio for the polymer solutions leading to thermodynamically stable nanogels with the ability to encapsulate active compounds. The influence of temperature on the formation of nanogels was also studied. The consequent conformational changes were monitored using ultraviolet-visible (UV-VIS) spectrophotometry. The spectrophotometric investigations combined with diffraction light scattering (DLS) technique and zeta potential measurement results were correlated to determine the interaction mechanism and assess the self-assembling processes during nanogel formation. It was found that the hydrodynamic diameter (D_h) of the nanoparticles increased slightly at acidic pH, and the protonation of ionizable amino groups with the pH was confirmed by the zeta potential measurements. MAC/BSA nanogels also exhibited antimicrobial properties after being loaded with amoxicillin (Amox), which is an antibiotic used for the treatment of various infections. The experimental data resulting from this study provide theoretical guidance for the design and development of attractive nanocarriers for a large variety of biomedical applications.

New Trends in Bio-Based Aerogels

(1) Background: The fascinating properties of currently synthesized aerogels associated with the flexible approach of sol-gel chemistry play an important role in the emergence of special biomedical applications. Although it is increasingly known and mentioned, the potential of aerogels in the medical field is not sufficiently explored. Interest in aerogels has increased greatly in recent decades due to their special properties, such as high surface area, excellent thermal and acoustic properties, low density and thermal conductivity, high porosity, flame resistance and humidity, and low refractive index and dielectric constant. On the other hand, high manufacturing costs and poor mechanical strength limit the growth of the market. (2) Results: In this paper, we analyze more than 180 articles from recent literature studies focused on the dynamics of aerogels research to summarize the technologies used in manufacturing and the properties of materials based on natural polymers from renewable sources. Biomedical applications of these bio-based materials are also introduced. (3) Conclusions: Due to their complementary functionalities (bioactivity, biocompatibility, biodegradability, and unique chemistry), bio-based materials provide a vast capability for utilization in the field of interdisciplinary and multidisciplinary scientific research.

Mechanisms of whey protein isolate interaction with basil seed gum: Influence of pH and protein-polysaccharide ratio

In the present work, we determined the structure-function relationships of basil seed gum (BSG) and whey protein isolate (WPI) mixtures at the start of soluble complex formation, maximum soluble complex formation and predominant thermodynamic incompatibility to understand BSG:WPI blends interaction behavior. Accordingly, turbidity and zeta potential were analyzed in the pH range of 2.0-7.0 and BSG:WPI ratios of 1:4, 1:6.6 and 1:9. Dynamic rheometry was used to evaluate samples at three different pHs. Additionally, dilute solution properties of BSG, WPI and their blends were studied at pH = 7.0. Independent of mixture ratio, all dispersions showed maximum interaction at pH = 5.0, the start of soluble complex formation around pH = 6.0 and thermodynamic incompatibility interaction behavior at pH = 7.0. Cole-Cole plots based on dynamic rheometry supported the Gibbs free energy change of mixtures based on intrinsic viscosity data. These results are important to create new structures from mixtures of proteins and polysaccharides.

Investigation of the magnetic field effect upon interpolymeric complexes formation based on bovine serum albumin and poly(aspartic acid)

The study presents a novel strategy for obtaining highly ordered interpolymeric complexes based on a protein, bovine serum albumin and a synthetic polymer, poly(aspartic acid). In this approach, experimental tests were carried out in the presence of a magnetic field of different intensities, namely 0.11 T and 0.3 T produced by permanent magnets. The influence of the magnetic force on the complexation process and the resulted self-assembled structures were studied by means of FTIR spectroscopy, X-ray diffraction, DLS, SEM microscopy and in vitro assay. The changes in the FTIR spectra acquired after 24 h of exposure were connected with conformational changes in the secondary structure and increased interactions between polymers, particularly when a higher intensity field was used. Due to a large anisotropy of magnetic susceptibility characteristic to both proteins and polypeptides, the magnetic field generated ordered assemblies consisting in globular structures of nanometric dimensions. This assembly strategy using magnets, along with remote manipulation capability can provide a versatile, contact-free, and inexpensive tool to create new, complex materials with tailorable characteristics.

Multicomponent peptide assemblies

Self-assembled peptide nanostructures have been increasingly exploited as functional materials for applications in biomedicine and energy. The emergent properties of these nanomaterials determine the applications for which they can be exploited. It has recently been appreciated that nanomaterials composed of multicomponent coassembled peptides often display unique emergent properties that have the potential to dramatically expand the functional utility of peptide-based materials. This review presents recent efforts in the development of multicomponent peptide assemblies. The discussion includes multicomponent assemblies derived from short low molecular weight peptides, peptide amphiphiles, coiled coil peptides, collagen, and β-sheet peptides. The design, structure, emergent properties, and applications for these multicomponent assemblies are presented in order to illustrate the potential of these formulations as sophisticated next-generation bio-inspired materials.