Strategies for Fabricating Protein Films for Biomaterials Applications

Soy Protein-Based Wound Dressings: A Review of Their Preparation, Properties, and Perspectives

Wound healing is a major challenge worldwide, and people have been researching wound dressings that can promote wound healing for decades. Natural biobased materials, such as polysaccharides and proteins, have been widely used in the development of wound dressings. Among them, soy protein-based materials have attracted the interest of a wide range of researchers due to their safety, biocompatibility, controlled degradation, and ability to be mixed with other materials. However, there has been a lack of comments on these soy protein-based wound dressings. This work reviews various forms of soy protein-based wound dressings, such as hydrogels, films, and others, which could be prepared through physical/chemical cross-linking with synthetic or natural polymers. The important role played by soy protein-based materials in the wound healing phase and their properties will be examined, such as their anti-inflammatory, antioxidant, angiogenesis-promoting, cellular biocompatibility, self-healing ability, adhesion, antimicrobial, and tunable mechanical properties. Additionally, insights into the market prospects and trends for soy protein dressings are provided, clarifying the enormous development potential of soy protein as a new type of wound repair material.

Hybrid Micro-/Nanoprotein Platform Provides Endocrine-like and Extracellular Matrix-like Cell Delivery of Growth Factors

Protein materials are versatile tools in diverse biomedical fields. Among them, artificial secretory granules (SGs), mimicking those from the endocrine system, act as mechanically stable reservoirs for the sustained release of proteins as oligomeric functional nanoparticles. Only validated in oncology, the physicochemical properties of SGs, along with their combined drug-releasing and scaffolding abilities, make them suitable as smart topographies in regenerative medicine for the prolonged delivery of growth factors (GFs). Thus, considering the need for novel, safe, and cost-effective materials to present GFs, in this study, we aimed to biofabricate a protein platform combining both endocrine-like and extracellular matrix fibronectin-derived (ECM-FN) systems. This approach is based on the sustained delivery of a nanostructured histidine-tagged version of human fibroblast growth factor 2. The GF is presented onto polymeric surfaces, interacting with FN to spontaneously generate nanonetworks that absorb and present the GF in the solid state, to modulate mesenchymal stromal cell (MSC) behavior. The results show that SGs-based topographies trigger high rates of MSCs proliferation while preventing differentiation. While this could be useful in cell therapy manufacture demanding large numbers of unspecialized MSCs, it fully validates the hybrid platform as a convenient setup for the design of biologically active hybrid surfaces and in tissue engineering for the controlled manipulation of mammalian cell growth.

Protein-based bioactive coatings: from nanoarchitectonics to applications

Protein-based bioactive coatings have emerged as a versatile and promising strategy for enhancing the performance and biocompatibility of diverse biomedical materials and devices. Through surface modification, these coatings confer novel biofunctional attributes, rendering the material highly bioactive. Their widespread adoption across various domains in recent years underscores their importance. This review systematically elucidates the behavior of protein-based bioactive coatings in organisms and expounds on their underlying mechanisms. Furthermore, it highlights notable advancements in artificial synthesis methodologies and their functional applications in vitro. A focal point is the delineation of assembly strategies employed in crafting protein-based bioactive coatings, which provides a guide for their expansion and sustained implementation. Finally, the current trends, challenges, and future directions of protein-based bioactive coatings are discussed.

Synthesis and functionalization of scalable and versatile 2D protein films via amyloid-like aggregation

Two-dimensional (2D) protein films can be used to modify the properties of surfaces, and find applications predominantly in the fields of biomaterials, lithography, optics and electronics. However, it is difficult to produce scalable homogeneous and robust protein films with an easy, low-cost, green and efficient method. Further challenges include encapsulating and releasing functional building blocks in the film without inactivating them, and maintaining or improving the bioactivities of proteins used for the formation of the films. Here we detail the process to prepare large 2D protein films with user-defined features and structures via the amyloid-like aggregation of commonly synthesized proteins. These films can be synthesized at meter scales, have high interface adhesion, high functional expansibility and tunable functional properties, obtained by controlling the position of the disulfide bond breakage. For example, we can retain or even enhance the natural antibacterial, biomineralization and antifouling activity of proteins involved in film formation, and the properties can also be expanded through the physical blending or chemical grafting of additional functional blocks on the surface of the film. A 2D protein film can be prepared in ~3 h using four alternative coating techniques: immersion, transfer, hydrogel stamping and spraying. The characterization process of the film requires ~5 d. The procedure can be carried out by users with basic expertise in materials science.

High-precision targeting and destruction of cancer-associated PDGFR-β+ stromal fibroblasts through self-assembling, protein-only nanoparticles

The need for more effective and precision medicines for cancer has pushed the exploration of new materials appropriate for drug delivery and imaging, and alternative receptors for targeting. Among the most promising strategies, finding suitable cell surface receptors and targeting agents for cancer-associated platelet derived growth factor receptor β (PDGFR-β)+ stromal fibroblasts is highly appealing. As a neglected target, this cell type mechanically and biologically supports the growth, progression, and infiltration of solid tumors in non-small cell lung, breast, pancreatic, and colorectal cancers. We have developed a family of PDGFR-β-targeted nanoparticles based on biofabricated, self-assembling proteins, upon hierarchical and iterative selective processes starting from four initial candidates. The modular protein PDGFD-GFP-H6 is well produced in recombinant bacteria, resulting in structurally robust oligomeric particles that selectively penetrates into PDGFR-β+ stromal fibroblasts in a dose-dependent manner, by means of the PDGFR-β ligand PDGFD. Upon in vivo administration, these GFP-carrying protein nanoparticles precisely accumulate in tumor tissues and enlighten them for IVIS observation. When GFP is replaced by a microbial toxin, selective tumor tissue destruction is observed associated with a significant reduction in tumor volume growth. The presented data validate the PDGFR-β/PDGFD pair as a promising toolbox for targeted drug delivery in the tumor microenvironment and oligomeric protein nanoparticles as a powerful instrument to mediate highly selective biosafe targeting in cancer through non-cancer cells. STATEMENT OF SIGNIFICANCE: We have developed a transversal platform for nanoparticle-based drug delivery into cancer-associated fibroblasts. This is based on the engineered modular protein PDGFD-GFP-H6 that spontaneously self-assemble and selectively penetrates into PDGFR-β+ stromal fibroblasts in a dose-dependent manner, by means of the PDGFR-β ligand PDGFD. In vivo, these protein nanoparticles accumulate in tumor and when incorporating a microbial toxin, they destroy tumor tissues with a significant reduction in tumor volume, in absence of side toxicities. The data presented here validate the PDGFR-β/PDGFD pair as a fully versatile toolbox for targeted drug delivery in the tumor microenvironment intended as a synergistic treatment.

Role of Driving Force on Engineering Layer-by-Layer Protein/Polyphenol Coating with Flexible Structures and Properties

Protein-based coatings are of immense interest due to their rich biological functions. Layer-by-layer (LbL) assembly, as a powerful means of transferring protein functions to the material surface, has received widespread attention. However, the assembly mechanism of protein-based LbL coatings is still far from being explained, not only because of protein structure and function diversity but also characterization limitations. Herein, we monitored in situ the LbL assembly process of tannic acid (TA) and lysozyme (Lyz), a classic pair of polyphenol and protein, by combining quartz crystal microbalance with dissipation monitoring (QCM-D) and spectroscopic ellipsometry (SE). The water content, morphology, mechanical properties, antioxidant activity, and the driving force of TA-Lyz coating engineered under different pH values were analyzed in detail by various techniques. The water content, a key factor in TA-Lyz coatings, increased with increasing assembled pH values, which resulted in a porous morphology, inhomogeneous mechanical distribution, faster assembly growth, and better antioxidant activity in both acellular and cellular levels. In addition, high water content is unfavorable to both entropy and enthalpy changes, and the thermodynamic driving force of TA and Lyz assembly mainly comes from the enthalpy change brought by the noncovalent interaction between TA and Lyz. These results provide new insights into engineering the structure, function, and assembly mechanisms of protein-based coatings.

BSA modification of bacterial surface: a promising anti-cancer therapeutic strategy

BACKGROUND

Attenuated live bacterial therapy and medical BSA materials have their own advantages in anti-cancer research, and their combination is expected to overcome some of the disadvantages of conventional anti-cancer therapeutics.

METHODS AND OBJECTIVE

Utilizing the high affinity between biotin and streptavidin, BSA modification on the surface of Escherichia coli (E. coli) was achieved. Then, the adhesion and targeting abilities of BSA modified E. coli was explored on different bladder cancer cells, and the underlying mechanism was also investigated.

RESULTS

BSA modification on the surface of E. coli enhances its ability to adhere and target cancer cells, and we speculate that these characteristics are related to the expression of SPARC in different bladder cancer cell lines.

CONCLUSION

BSA and live bacteria have their own advantages in anti-cancer research. In this study, we found that E. coli surface-modified by BSA had stronger adhesion and targeting effects on bladder cancer cells with high expression of SPARC. These findings pave the way for the future studies exploring the combination of BSA combined with live bacteria for cancer therapy.

Recent advance in biomass membranes: Fabrication, functional regulation, and antimicrobial applications

Both inorganic and polymeric membranes have been widely applied for antimicrobial applications. However, these membranes exhibit low biocompatibility, weak biodegradability, and potential toxicity to human being and environment. Biomass materials serve as excellent candidates for fabricating functional membranes to address these problems due to their unique physical, chemical, and biological properties. Here we present recent progress in the fabrication, functional regulation, and antimicrobial applications of various biomass-based membranes. We first introduce the types of biomass membranes and their fabrication methods, including the phase inversion, vacuum filtration, electrospinning, layer-by-layer self-assembly, and coating. Then, the strategies on functional regulation of biomass membranes by adding 0D, 1D, and 2D nanomaterials are presented and analyzed. In addition, antibacterial, antifungal, and antiviral applications of biomass-based functional membranes are summarized. Finally, potential development aspects of biomass membranes are discussed and prospected. This comprehensive review is valuable for guiding the design, synthesis, structural/functional tailoring, and sustainable utilization of biomass membranes.

Impact of adding prebiotics and probiotics on the characteristics of edible films and coatings- a review

Nowadays, conventional packaging materials made using non-renewable sources are being replaced by more sustainable alternatives such as natural biopolymers (proteins, polysaccharides, and lipids). Within edible packaging, one can differentiate between edible films or coatings. This packaging can be additivated with bioactive compounds to develop functional food packaging, capable of improving the consumer's state of health. Among the bioactive compounds that can be added are probiotics and prebiotics. This review novelty highlighted recent research on edible films and coatings additivated with probiotics and prebiotics, the interactions between them and the matrix and the changes in their physic, chemical and mechanical properties. When bioactive compounds are added, critical factors must be considered when selecting the most suitable production processes. Particularly, as probiotics are living microorganisms, they are more sensitive to certain factors, such as pH or temperature, while prebiotic compounds are less problematic. The interactions that occur inside the matrix can be divided into two main groups: covalent bonding (-NH₂, -NHR, -OH, -CO₂H, etc) and non-covalent interactions (van der Waals forces, hydrogen bonding, hydrophobic and electrostatic interactions). When probiotics and prebiotics are added, covalent and non-covalent interactions are modified. The physical and mechanical properties of films and coatings depend directly on the interactions that take place between the biopolymers that form their matrix. Greater knowledge about the influence of these compounds on the interactions that occur inside the matrix will allow better control of these properties and better understanding of the behaviour of edible packaging additivated with probiotics and prebiotics.

A review of medical wearables: materials, power sources, sensors, and manufacturing aspects of human wearable technologies

Wearable technology is a promising and revolutionary technology that is changing some aspects of our standard of living to a great extent, including health monitoring, sport and fitness, performance tracking, education, and entertainment. This article presents a comprehensive literature review of over 160 articles related to state-of-the-art human wearable technologies. We provide a thorough understanding of the materials, power sources, sensors, and manufacturing processes, and the relationships between these to capture opportunities for enhancement and challenges to overcome in wearables. As a result of our review, we have determined the need for the development of a comprehensive, robust manufacturing system alongside specific standards and regulations that take into account wearables' unique characteristics. Seeing the whole picture will provide a frame reference and road map for researchers and industries through the design, manufacturing, and commercialisation of effective, portable, self-powered, multi-sensing ultimate future wearable devices and create opportunities for new innovations and applications.

Biopolymer coating for particle surface engineering and their biomedical applications

Surface engineering of particles based on a polymeric coating is of great interest in materials design and applications. Due to the disadvantages of non-biodegradability and undesirable biocompatibility, the application of petroleum-based synthetic polymers coating in the biomedical field has been greatly limited. In addition, there is lack of a universal surface modification method to functionalize particles of different compositions, sizes, shapes, and structures. Thus, it is imperative to develop a versatile biopolymeric coating with good biocompatibility and tunable biodegradability for the preparation of functional particle materials regardless of their surface chemical and physical structures. Recently, the natural polysaccharide polymers (e.g. chitosan and cellulose), polyphenol-based biopolymers (e.g. polydopamine and tannic acid), and proteins (e.g. amyloid-like aggregates) have been utilized in surface modification of particles, and applications of these modified particles in the field of biomedicine have been also intensively exploited. In this review, the preparation of the above three coatings on particles surface are summarized, and the applications of these materials in drug loading/release, biomineralization, cell immobilization/protection, enzyme immobilization/protection, and antibacterial/antiviral are exemplified. Finally, the challenges and the future research directions on biopolymer coating for particles surface engineering are prospected.

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This review highlights the importance of particle surface engineering in the materials field. .

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This review summarizes biopolymer coating for particle surface engineering and their biomedical applications. .

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This review discusses the key challenges and directions for future research and development of particle surface engineering .

Bioinspired silk fibroin materials: From silk building blocks extraction and reconstruction to advanced biomedical applications

Silk fibroin has become a promising biomaterial owing to its remarkable mechanical property, biocompatibility, biodegradability, and sufficient supply. However, it is difficult to directly construct materials with other formats except for yarn, fabric and nonwoven based on natural silk. A promising bioinspired strategy is firstly extracting desired building blocks of silk, then reconstructing them into functional regenerated silk fibroin (RSF) materials with controllable formats and structures. This strategy could give it excellent processability and modifiability, thus well meet the diversified needs in biomedical applications. Recently, to engineer RSF materials with properties similar to or beyond the hierarchical structured natural silk, novel extraction and reconstruction strategies have been developed. In this review, we seek to describe varied building blocks of silk at different levels used in biomedical field and their effective extraction and reconstruction strategies. This review also present recent discoveries and research progresses on how these functional RSF biomaterials used in advanced biomedical applications, especially in the fields of cell-material interactions, soft tissue regeneration, and flexible bioelectronic devices. Finally, potential study and application for future opportunities, and current challenges for these bioinspired strategies and corresponding usage were also comprehensively discussed. In this way, it aims to provide valuable references for the design and modification of novel silk biomaterials, and further promote the high-quality-utilization of silk or other biopolymers.

Protein Assembly by Design

Proteins are nature's primary building blocks for the construction of sophisticated molecular machines and dynamic materials, ranging from protein complexes such as photosystem II and nitrogenase that drive biogeochemical cycles to cytoskeletal assemblies and muscle fibers for motion. Such natural systems have inspired extensive efforts in the rational design of artificial protein assemblies in the last two decades. As molecular building blocks, proteins are highly complex, in terms of both their three-dimensional structures and chemical compositions. To enable control over the self-assembly of such complex molecules, scientists have devised many creative strategies by combining tools and principles of experimental and computational biophysics, supramolecular chemistry, inorganic chemistry, materials science, and polymer chemistry, among others. Owing to these innovative strategies, what started as a purely structure-building exercise two decades ago has, in short order, led to artificial protein assemblies with unprecedented structures and functions and protein-based materials with unusual properties. Our goal in this review is to give an overview of this exciting and highly interdisciplinary area of research, first outlining the design strategies and tools that have been devised for controlling protein self-assembly, then describing the diverse structures of artificial protein assemblies, and finally highlighting the emergent properties and functions of these assemblies.

Secondary Structure-Dominated Layer-by-Layer Growth Mode of Protein Coatings

Benefiting from the luxury functions of proteins, protein coatings have been extended to various applications, including tissue engineering scaffolds, drug delivery, antimicrobials, sensing and diagnostic equipment, food packaging, etc. Fast construction of protein coatings is always interesting to materials science and significant to industrialization. Here, we report a layer-by-layer (LbL) multilayer-constructed coating of tannic acid (TA) and lysozyme (Lyz), in which the secondary conformations of Lyz dominate the growth rate of the TA/Lyz coating. As well characterized by various techniques (quartz crystal microbalance with dissipation (QCM-D), circular dichroism (CD) spectra, Fourier transform infrared (FTIR) spectroscopy, atomic force microscopy (AFM), contact angle, etc.), TA-induced conformational transition of Lyz to α-helices occurs at pH 8 from other secondary structures (β-sheets, β-turns, and random coils), which leads to the very fast growth of TA/Lyz with a number of deposited bilayers, with thicknesses of more than 90 nm for six bilayers. In contrast to the leading conformation of α-helices at pH 8, Lyz displayed multiple conformations (α-helices, β-sheets, β-turns, and random coils) at pH 6, which resulted in coating thicknesses of less than 30 nm for six bilayers. By the addition of NaCl, Tween 20, and urea, we further confirmed that the secondary conformations of Lyz relied greatly on the interactions between TA and Lyz and dominated the growth rate of the multilayers. We believe that these findings will help to understand the transformation of secondary conformations by TA or other polyphenols and inspire a new route to quickly build protein coatings.

Protein-Based Films as Antifouling and Drug-Eluting Antimicrobial Coatings for Medical Implants

Nosocomial infections, caused by bacterial contamination of medical devices and implants, are a serious healthcare concern. We demonstrate here, the use of fluorous-cured protein nanofilm coatings for generating antimicrobial surfaces. In this approach, bacteria-repelling films are created by heat-curing proteins in fluorous media. These films are then loaded with antibiotics, with release controlled via electrostatic interactions between therapeutic and protein film building blocks to provide bactericidal surfaces. This film fabrication process is additive-free, biocompatible, biodegradable, and can be used to provide antimicrobial coatings for both three-dimensional (2D) and 3D objects for use in indwelling devices.

Antimicrobial Peptide-Loaded Pectolite Nanorods for Enhancing Wound-Healing and Biocidal Activity of Titanium

Titanium is widely utilized for manufacturing medical implants due to its inherent mechanical strength and biocompatibility. Recent studies have focused on developing coatings to impart unique properties to Ti implants, such as antimicrobial behavior, enhanced cell adhesion, and osteointegration. Ca- and Si-based ceramic (CS) coatings can enhance bone integration through the release of Ca and Si ions. However, high degradation rates of CS ceramics create a basic environment that reduces cell viability. Polymeric or protein-based coatings may be employed to modulate CS degradation. However, it is challenging to ensure coating stability over extended periods of time without compromising biocompatibility. In this study, we employed a fluorous-cured collagen shell as a drug-loadable scaffold around CS nanorod coatings on Ti implants. Fluorous-cured collagen coatings have enhanced mechanical and enzymatic stability and are able to regulate the release of Ca and Si ions. Furthermore, the collagen scaffold was loaded with antimicrobial peptides to impart antimicrobial activity while promoting cell adhesion. These multifunctional collagen coatings simultaneously regulate the degradation of CS ceramics and enhance antimicrobial activity, while maintaining biocompatibility.

Efficient development of silk fibroin membranes on liquid surface for potential use in biomedical materials

Silk fibroin (SF) protein is versatile for the application of biomaterials due to its excellent mechanical properties, biocompatibility and biodegradability. However, the efficient way to fabricate SF membranes with special structure is still challenging. Here, we develop an efficient and simple way to create SF membranes on the liquid (i.e. subphase) surface. It is essential to prepare highly concentrated SF solution with low surface tension by dissolving the degummed SF powders in 6% (w/v) LiBr/methanol solution by one step. 95 wt% polyethylene glycol (PEG) 200 and 30 wt% (NH₄)₂SO₄ are the subphases, on which the SF solution spreads quickly, generating nonporous and microporous SF membranes (SFM-1 and SFM-2), respectively. PEG 200 causes more ordered molecular packing (β-sheets) in SFM-1. While Fast diffusion and denaturation of SF on (NH₄)₂SO₄ solution lead to the formation of microporous, water-unstable membrane SFM-2. Both membranes have good transparency, hydrophilicty, and mechanical properties. To fabricate antibacterial biomaterials, we design a composite membrane by SFM-1 and SFM-2 sandwiching a layer of hydroxypropyl trimethylammonium chloride chitosan (HACC) to provide antibacterial functions. The sandwich membrane has good cell viability and antibacterial properties, showing potential use for biomedical materials.