Nanocomposites from biopolymer hydrogels: Blueprints for white biotechnology and green materials chemistry

Revolutionizing biomedicine: advancements, applications, and prospects of nanocomposite macromolecular carbohydrate-based hydrogel biomaterials: a review

Nanocomposite hydrogel biomaterials represent an exciting Frontier in biomedicine, offering solutions to longstanding challenges. These hydrogels are derived from various biopolymers, including fibrin, silk fibroin, collagen, keratin, gelatin, chitosan, hyaluronic acid, alginate, carrageenan, and cellulose. While these biopolymers possess inherent biocompatibility and renewability, they often suffer from poor mechanical properties and rapid degradation. Researchers have integrated biopolymers such as cellulose, starch, and chitosan into hydrogel matrices to overcome these limitations, resulting in nanocomposite hydrogels. These innovative materials exhibit enhanced mechanical strength, improved biocompatibility, and the ability to finely tune drug release profiles. The marriage of nanotechnology and hydrogel chemistry empowers precise control over these materials' physical and chemical properties, making them ideal for tissue engineering, drug delivery, wound healing, and biosensing applications. Recent advancements in the design, fabrication, and characterization of biopolymer-based nanocomposite hydrogels have showcased their potential to transform biomedicine. Researchers are employing strategic approaches for integrating biopolymer nanoparticles, exploring how nanoparticle properties impact hydrogel performance, and utilizing various characterization techniques to evaluate structure and functionality. Moreover, the diverse biomedical applications of these nanocomposite hydrogels hold promise for improving patient outcomes and addressing unmet clinical needs.

Magnetic Field Alignment, a Perspective in the Engineering of Collagen-Silica Composite Biomaterials

Major progress in the field of regenerative medicine is expected from the design of artificial scaffolds that mimic both the structural and functional properties of the ECM. The bionanocomposites approach is particularly well fitted to meet this challenge as it can combine ECM-based matrices and colloidal carriers of biological cues that regulate cell behavior. Here we have prepared bionanocomposites under high magnetic field from tilapia fish scale collagen and multifunctional silica nanoparticles (SiNPs). We show that scaffolding cues (collagen), multiple display of signaling peptides (SiNPs) and control over the global structuration (magnetic field) can be combined into a unique bionanocomposite for the engineering of biomaterials with improved cell performances.

Multivalent Clustering of Adhesion Ligands in Nanofiber-Nanoparticle Composites

Because the positioning and clustering of biomolecules within the extracellular matrix dictates cell behaviors, the engineering of biomaterials incorporating bioactive epitopes with spatial organization tunable at the nanoscale is of primary importance. Here we used a highly modular composite approach combining peptide amphiphile (PA) nanofibers and silica nanoparticles, which are both easily functionalized with one or several bioactive signals. We show that the surface of silica nanoparticles allows the clustering of RGDS bioactive signals leading to improved adhesion and spreading of fibroblast cells on composite hydrogels at an epitope concentration much lower than in PA-only based matrices. Most importantly, by combining the two integrin-binding sequences RGDS and PHSRN on nanoparticle surfaces, we improved cell adhesion on the PA nanofiber/particle composite hydrogels, which is attributed to synergistic interactions known to be effective only for peptide intermolecular distance of ca. 5 nm. Such composites with soft and hard nanostructures offer a strategy for the design of advanced scaffolds to display multiple signals and control cell behavior.

Engineering next-generation bioinks with nanoparticles: moving from reinforcement fillers to multifunctional nanoelements

The application of additive manufacturing in the biomedical field has become a hot topic in the last decade owing to its potential to provide personalized solutions for patients. Different bioinks have been designed trying to obtain a unique concoction that addresses all the needs for tissue engineering and drug delivery purposes, among others. Despite the remarkable progress made, the development of suitable bioinks which combine printability, cytocompatibility, and biofunctionality is still a challenge. In this sense, the well-established synthetic and functionalization routes to prepare nanoparticles with different functionalities make them excellent candidates to be combined with polymeric systems in order to generate suitable multi-functional bioinks. In this review, we briefly discuss the most recent advances in the design of functional nanocomposite hydrogels considering their already evaluated or potential use as bioinks. The scientific development over the last few years is reviewed, focusing the discussion on the wide range of functionalities that can be incorporated into 3D bioprinted constructs through the addition of multifunctional nanoparticles in order to increase their regenerative potential in the field of tissue engineering.

Type I Collagen-Fibrin Mixed Hydrogels: Preparation, Properties and Biomedical Applications

Type I collagen and fibrin are two essential proteins in tissue regeneration and have been widely used for the design of biomaterials. While they both form hydrogels via fibrillogenesis, they have distinct biochemical features, structural properties and biological functions which make their combination of high interest. A number of protocols to obtain such mixed gels have been described in the literature that differ in the sequence of mixing/addition of the various reagents. Experimental and modelling studies have suggested that such co-gels consist of an interpenetrated structure where the two proteins networks have local interactions only. Evidences have been accumulated that immobilized cells respond not only to the overall structure of the co-gels but can also exhibit responses specific to each of the proteins. Among the many biomedical applications of such type I collagen-fibrin mixed gels, those requiring the co-culture of two cell types with distinct affinity for these proteins, such as vascularization of tissue engineering constructs, appear particularly promising.

Differentiation of neural-type cells on multi-scale ordered collagen-silica bionanocomposites

Cells respond to biophysical and biochemical signals. We developed a composite filament from collagen and silica particles modified to interact with collagen and/or present a laminin epitope (IKVAV) crucial for cell-matrix adhesion and signal transduction. This combines scaffolding and signaling and shows that local tuning of collagen organization enhances cell differentiation.

Bio-/Nanoimmobilization Platform Based on Bioinspired Fibrin-Bone@Polydopamine-Shell Adhesive Composites for Biosensing

Inspired by blood coagulation and mussel adhesion, we report novel adhesive fibrin-bone@polydopamine (PDA)-shell composite matrix as highly efficient immobilization platform for biomacromolecules and nanomaterials. Fibrin, as a bioglue, and PDA, as a chemical adhesive, are integrated in a one-pot simultaneous polymerization consisting of biopolymerization of fibrinogen and chemical polymerization of dopamine. Fibrin fibers act as adhesive bones to construct scaffold, while PDA coat on the scaffold to form adhesive shell, generating 3D porous composite matrix with unique bone@shell structure. Two types of enzymes (glucose oxidase and acetylcholinesterase) and Au nanoparticles were adopted as respective model biomolecules and nanomaterials to investigate the immobilization capability of the matrix. The bionanocomposites showed high efficiency in capturing nanoparticles and enzymes, as well as significant mass-transfer and biocatalysis efficiencies. Therefore, the bionanocomposites exhibited significant potential in biosensing of glucose and paraoxon with limits of detection down to 5.2 μM and 4 ppt, respectively. The biological-chemical-combined polymerization strategy and composite platform with high immobilization capacity and mass-transfer efficiency open up a novel way for the preparation of high-performance bionanocomposites for various applications, in particular, biosensing.

Non-Chloride in Situ Preparation of Nano-Cuprous Oxide and Its Effect on Heat Resistance and Combustion Properties of Calcium Alginate

With Cu²⁺ complexes as precursors, nano-cuprous oxide was prepared on a sodium alginate template excluded of Cl^- and based on which the calcium alginate/nano-cuprous oxide hybrid materials were prepared by a Ca²⁺ crosslinking and freeze-drying process. The thermal degradation and combustion behavior of the materials were studied by related characterization techniques using pure calcium alginate as a comparison. The results show that the weight loss rate, heat release rate, peak heat release rate, total heat release rate and specific extinction area of the hybrid materials were remarkably lower than pure calcium alginate, and the flame-retardant performance was significantly improved. The experimental data indicates that nano-cuprous oxide formed a dense protective layer of copper oxide, calcium carbonate and carbon by lowering the initial degradation temperature of the polysaccharide chain during thermal degradation and catalytically dehydrating to char in the combustion process, and thereby can isolate combustible gases, increase carbon residual rates, and notably reduce heat release and smoke evacuation.

Exploring the cell-protein-mineral interfaces: Interplay of silica (nano)rods@collagen biocomposites with human dermal fibroblasts

The benefits of associating biological polymers with nanomaterials within functional bionanocomposite hydrogels have already been evidenced both in vitro and in vivo. However their development as effective biomaterials requires to understand and tune the interactions at the cell-protein-mineral ternary interface. With this purpose, we have studied here the impact of silica (nano)rods on the structural and rheological properties of type I collagen hydrogels ​and on the behavior of human dermal fibroblasts. High collagen concentrations were beneficial to the material mechanical properties, whereas silica rods could exert a positive effect on these at both low and high content. Electron microscopy evidenced strong bio-mineral interactions, emphasizing the true composite nature of these materials. In contrast, adhesion and proliferation studies showed that, despite these interactions, fibroblasts can discriminate between the protein and the inorganic phases and penetrate the collagen network to limit direct contact with silica. Such a divergence between physicochemical characteristics and biological responses has major implications for the prediction of the in vivo fate of nanocomposite biomaterials.

Chitosan Hydrogels and Bionanocomposites Formed through the Mineralization and Regulated Charging

The account presents survey of our systematic studies on chitosan. Only this polysaccharide bears cationic charges, possesses antimicrobial activity and wound healing ability that make it highly appropriate for using in medicine, biomedical engineering, cosmetics, food, packaging. However, its application meets with severe limitation. Chitosan belongs to polysaccharides that do not jellify solutions. Main approaches are based on the chemical modifications and cross-linking, but these treatments impairs therewith the biocompatibility and biological activity of chitosan. We have developed approaches in which monolithic hydrogels are fabricated via the mineralization of polysaccharide by method of green sol-gel chemistry and via the formation of polyelectrolyte complex with oppositely charged counterparts in the regime of its charging by means of regulated acidification. The latter approach was also extended for the preparation of chitosan bionanocomposites and films with nanoparticles.

Highly Efficient Flame Retardant Hybrid Composites Based on Calcium Alginate/Nano-Calcium Borate

Hybrid composites with low flammability based on renewable calcium alginate and nano-calcium borate were fabricated using an in situ method through a simple, eco-friendly vacuum drying process. The composites were characterized by X-ray diffractometry (XRD), Fourier transform infrared spectrum (FTIR), scanning electron microscopy (SEM), and thermogravimetric analysis (TGA). The combustion behavior and flammability of the composites were assessed by using the limiting oxygen index (LOI) and cone calorimetry (CONE) tests. The composites showed excellent thermal stability and achieved nonflammability with an LOI higher than 60. Pyrolysis was investigated using pyrolysis⁻gas chromatography⁻mass spectrometry (Py-GC-MS) and the results showed that fewer sorts of cracking products were produced from the hybrid composites compared with the calcium alginate. A possible thermal degradation mechanism of composites was proposed based on the experimental data. The combined results indicate that the calcium borate had a nano-effect, accumulating more freely in the hybrid composites and contributing significantly to both the solid phase and gas phase, resulting in an efficient improvement in the flame retardancy of the composites. Our study provides a novel material with promising potentiality for flame retardant applications.

Carbon-dot–hydrogel for enzyme-mediated bacterial detection

A hybrid carbon-dot (C-dot)–hydrogel matrix was constructed and employed for detection of bacteria.

Collagen: a network for regenerative medicine

The basic building block of the extra-cellular matrix in native tissue is collagen. As a structural protein, collagen has an inherent biocompatibility making it an ideal material for regenerative medicine. Cellular response, mediated by integrins, is dictated by the structure and chemistry of the collagen fibers. Fiber formation, via fibrillogenesis, can be controlled in vitro by several factors: pH, ionic strength, and collagen structure. After formation, fibers are stabilized via cross-linking. The final bioactivity of collagen scaffolds is a result of both processes. By considering each step of fabrication, scaffolds can be tailored for the specific needs of each tissue, improving their therapeutic potential.

Design and Cellular Fate of Bioinspired Au-Ag Nanoshells@Hybrid Silica Nanoparticles

Silica-coated gold-silver alloy nanoshells were obtained via a bioinspired approach using gelatin and poly-l-lysine (PLL) as biotemplates for the interfacial condensation of sodium silicate solutions. X-ray photoelectron spectroscopy was used as an efficient tool for the in-depth and complete characterization of the chemical features of nanoparticles during the whole synthetic process. Cytotoxicity assays using HaCaT cells evidenced the detrimental effect of the gelatin nanocoating and significant induction of late apoptosis after silicification. In contrast, PLL-modified nanoparticles had less biological impact that was further improved by the silica layer, and uptake rates of up to 50% of those of the initial particles could be achieved. These results are discussed considering the effect of nanosurface confinement of the biopolymers on their chemical and biological reactivity.

Bionanocomposite from self-assembled building blocks of nacre-like crystalline polymorph of chitosan with clay nanoplatelets

Films containing a new crystalline polymorph are prepared by a one-pot technique combining the formation of building blocks of clay nanoplatelets with chitosan macromolecules and their evaporation-induced self-assembly.

Facile strategy for the development of polyglucopyranose–silver hydrogel/films for antimicrobial applications

Development of silver nanoparticles entrapped hydrogels for antimicrobial applications.

Effect of maleimide-functionalized gold nanoparticles on hybrid biohydrogels properties

Nanoparticle cross-linking. Nanocomposite hydrogels with remarkable viscoelastic properties are prepared using maleimide coated gold nanoparticles as co cross-linkers for furan modified gelatin.

A renewable resource-derived thixotropic self-assembled supramolecular gel: magnetic stimuli responsive and real-time self-healing behaviour

A simple fluorescent, self-healing and magnetic responsive molecular gel was developed from a renewable resource.

Biopolymer colloids for controlling and templating inorganic synthesis

Biopolymers and biopolymer colloids can act as controlling agents and templates not only in many processes in nature, but also in a wide range of synthetic approaches. Inorganic materials can be either synthesized ex situ and later incorporated into a biopolymer structuring matrix or grown in situ in the presence of biopolymers. In this review, we focus mainly on the latter case and distinguish between the following possibilities: (i) biopolymers as controlling agents of nucleation and growth of inorganic materials; (ii) biopolymers as supports, either as molecular supports or as carrier particles acting as cores of core-shell structures; and (iii) so-called "soft templates", which include on one hand stabilized droplets, micelles, and vesicles, and on the other hand continuous scaffolds generated by gelling biopolymers.

Fibrillogenesis from nanosurfaces: multiphoton imaging and stereological analysis of collagen 3D self-assembly dynamics

The assembly of proteins into fibrillar structures is an important process that concerns different biological contexts, including molecular medicine and functional biomaterials. Engineering of hybrid biomaterials can advantageously provide synergetic interactions of the biopolymers with an inorganic component to ensure specific supramolecular organization and dynamics. To this aim, we designed hybrid systems associating collagen and surface-functionalized silica particles and we built a new strategy to investigate fibrillogenesis processes in such multicomponents systems, working at the crossroads of chemistry, physics and mathematics. The self-assembly process was investigated by bimodal multiphoton imaging coupling second harmonic generation (SHG) and 2 photon excited fluorescence (2PEF). The in-depth spatial characterization of the system was further achieved using the three-dimensional analysis of the SHG/2PEF data via mathematical morphology processing. Quantitation of collagen distribution around particles offers strong evidence that the chemically induced confinement of the protein on the silica nanosurfaces has a key influence on the spatial extension of fibrillogenesis. This new approach is unique in the information it can provide on 3D dynamic hybrid systems and may be extended to other associations of fibrillar molecules with optically responsive nano-objects.

Controlling the nano-bio interface to build collagen-silica self-assembled networks

Bio-hybrid networks are designed based on the self-assembly of surface-engineered collagen-silica nanoparticles. Collagen triple helices can be confined on the surface of sulfonate-modified silica particles in a controlled manner. This gives rise to hybrid building blocks with well-defined diameters and surface potentials. Taking advantage of the self-assembling properties of collagen, collagen-silica networks are further built-up in solution. The structural and specific recognition properties of the collagen fibrils are well-preserved within the hybrid assembly. A combination of calorimetry, dynamic light scattering, zetametry and microscopy studies indicates that network formation occurs via a surface-mediated mechanism where pre-organization of the protein chains on the particle surface favors the fibrillogenesis process. These results enlighten the importance of the nano-bio interface on the formation and properties of self-assembled bionanocomposites.

Bionanocomposites: Green sustainable materials for the near future

Bionanocomposites are a novel class of nanosized materials. They contain the constituent of biological origin and particles with at least one dimension in the range of 1–100 nm. There are similarities with nanocomposites but also fundamental differences in the methods of preparation, properties, functionalities, biodegradability, biocompatibility, and applications. The article includes two parts. Bionanocomposite definition and classification along with nanoparticles, biomaterials, and methods of their preparation are initially reviewed. Then, novel approaches developed by our team are presented. The first approach concerns the preparation of bionanocomposites from chitosan and nanoparticles. It is based on the regulated charging of polysaccharide by the gradual shift of solution pH. When charges appear, the biomacromolecules come into the electrostatic interactions with negatively charged nanoparticles that cause the jellification of solutions. It is also applied to form films. They have a nacre-like structure from stacked planar nanoparticles separated by aligned biomacromolecules. The second approach deals with the biomimicking mineralization of biopolymers by using a novel silica precursor. Its advantage over the current sol-gel processing is in the compatibility and regulation of processes and structure of generated silica. Another example of the mineralization is presented by titania. Syntheses are performed in anhydrous ethylene glycol. Processes and structure of bionanocomposites are regulated by water that is added in an amount to only hydrate functional groups in the carbohydrate macromolecule.