Infection Responsive Smart Delivery of Antibiotics Using Recombinant Spider Silk Nanospheres

Structure, production and application of spider silks

Spider silk plays a pivotal role in the diverse physiological activities of spiders, with its protein components exhibiting remarkable mechanical properties and biocompatibility. Spider silk proteins exhibit a high degree of repetitiveness, primarily constructed through the recurring arrangement of amino acid motifs, including (A)n, (GA)n, (GGX)n, and (GPGXX)n sequences. These repetitive sequences endow spider silk with different material properties. Recombinant spider silk proteins are produced through heterologous expression systems, and then spun into nanofibers using artificial spinning technology. These fibers have broad potential applications in the biomedical field, such as tissue engineering scaffolds, drug delivery carriers, sutures, and other biomaterials. However, enhancing the yield and performance of recombinant spider silk proteins, while facilitating large-scale production, continues to pose a significant challenge in the current landscape.

Neuraminidase and nitric oxide dual response via PSA-PLGA nanoparticles: A novel approach for controlling Glaesserella parasuis inflammation and infection

The overexpression of virulence factors and the induced inflammatory cytokine storm, resulting in tissue damage, represent significant challenges in treating antibiotic-resistant bacterial infections with conventional antibiotics. Herein, we have developed a bifunctional nanoparticle loaded with antibiotics (PSA@PLGA-TD/SMT) designed for precise response to the virulence proteins of drug-resistant bacteria while protecting the host from excessive inflammatory damage. This is achieved by modifying polylactic-co-glycolic acid (PLGA) nanoparticles with polysialic acid (PSA). Tildipirosin (TD), through hydrophobic interactions, is encapsulated within the core, while S-Methylisothiourea (SMT) is electrostatically adsorbed onto the shell layer. In vitro, the polysialic acid in the nanoparticles interacts with the neuraminidase overexpressed on the surface of Glaesserella parasuis (Gps), triggering disintegration and subsequent release of TD, which effectively kills the bacteria. Additionally, SMT functions to suppress the secretion of inducible nitric oxide synthase (NOS2), promoting the phenotypic transformation of macrophages and reducing the expression of pro-inflammatory factors. Ultimately, PSA@PLGA-TD/SMT achieves an extended drug circulation time through its prolonged retention effect, effectively alleviating discomfort caused by resistant bacteria. Therefore, the construction of nanocarriers for precise targeting of drug-resistant pathogens, delivering antibiotics, and preventing host-induced inflammatory damage presents an effective treatment strategy. This approach not only addresses the direct issue of bacterial eradication but also mitigates the collateral damage typically associated with severe infections, offering a more comprehensive and nuanced approach to managing drug-resistant bacterial infections.

Unleashing the power of silk-based proteins as biomaterials for cutting-edge drug delivery: a comprehensive review

Silk proteins, viz., sericin, fibroin and their modified forms etc., have been thoroughly researched as natural biopolymers for the development of varied nanomaterials exhibiting diverse biomedical applications. The silk proteins are extracted from the cocoons by degumming and treatment with soaps, followed by dissolution and dialysis against water. These proteins exhibit distinct mechanical and physicochemical characteristics including biocompatibility, controlled biodegradability, self-assembling traits, chemical modifiability, and adaptability, thus making it an ideal drug delivery vehicle. In this regard, silk protein-derived drug delivery systems have been reported as efficient carrier to encapsulate and stabilize the wide variety of pharmacological molecules, enzymes, proteins, vaccines, and even DNA, allowing them to remain active for a longer period of time. Further, different delivery carriers researched employing these proteins for multitude of applications include hydrogels, sponges, fibres, scaffolds and particulate delivery systems. Additionally, the chemical modification of silk proteins has further opened avenues for development of other modified silk proteins with improved physicochemical traits and hence exhibiting enormous potential in development of varied bioenhanced carrier systems. The current article thus provides the holistic information of characteristics, types of silk protein-based delivery carriers, and their fabrication techniques, while emphasizing the applications of different silk proteins in biomedicine and drug delivery.

Review of Spider Silk Applications in Biomedical and Tissue Engineering

This review will present the latest research related to the production and application of spider silk and silk-based materials in reconstructive and regenerative medicine and tissue engineering, with a focus on musculoskeletal tissues, and including skin regeneration and tissue repair of bone and cartilage, ligaments, muscle tissue, peripheral nerves, and artificial blood vessels. Natural spider silk synthesis is reviewed, and the further recombinant production of spider silk proteins. Research insights into possible spider silk structures, like fibers (1D), coatings (2D), and 3D constructs, including porous structures, hydrogels, and organ-on-chip designs, have been reviewed considering a design of bioactive materials for smart medical implants and drug delivery systems. Silk is one of the toughest natural materials, with high strain at failure and mechanical strength. Novel biomaterials with silk fibroin can mimic the tissue structure and promote regeneration and new tissue growth. Silk proteins are important in designing tissue-on-chip or organ-on-chip technologies and micro devices for the precise engineering of artificial tissues and organs, disease modeling, and the further selection of adequate medical treatments. Recent research indicates that silk (films, hydrogels, capsules, or liposomes coated with silk proteins) has the potential to provide controlled drug release at the target destination. However, even with clear advantages, there are still challenges that need further research, including clinical trials.

Development and challenges of antimicrobial peptide delivery strategies in bacterial therapy: A review

The escalating global prevalence of antimicrobial resistance poses a critical threat, prompting concerns about its impact on public health. This predicament is exacerbated by the acute shortage of novel antimicrobial agents, a scarcity attributed to the rapid surge in bacterial resistance. This review delves into the realm of antimicrobial peptides, a diverse class of compounds ubiquitously present in plants and animals across various natural organisms. Renowned for their intrinsic antibacterial activity, these peptides provide a promising avenue to tackle the intricate challenge of bacterial resistance. However, the clinical utility of peptide-based drugs is hindered by limited bioavailability and susceptibility to rapid degradation, constraining efforts to enhance the efficacy of bacterial infection treatments. The emergence of nanocarriers marks a transformative approach poised to revolutionize peptide delivery strategies. This review elucidates a promising framework involving nanocarriers within the realm of antimicrobial peptides. This paradigm enables meticulous and controlled peptide release at infection sites by detecting dynamic shifts in microenvironmental factors, including pH, ROS, GSH, and reactive enzymes. Furthermore, a glimpse into the future reveals the potential of targeted delivery mechanisms, harnessing inflammatory responses and intricate signaling pathways, including adenosine triphosphate, macrophage receptors, and pathogenic nucleic acid entities. This approach holds promise in fortifying immunity, thereby amplifying the potency of peptide-based treatments. In summary, this review spotlights peptide nanosystems as prospective solutions for combating bacterial infections. By bridging antimicrobial peptides with advanced nanomedicine, a new therapeutic era emerges, poised to confront the formidable challenge of antimicrobial resistance head-on.

Synthetic biology-guided design and biosynthesis of protein polymers for delivery

Vehicles derived from genetically engineered protein polymers have gained momentum in the field of biomedical engineering due to their unique designability, remarkable biocompatibility and excellent biodegradability. However, the design and production of these protein polymers with on-demand sequences and supramolecular architectures remain underexplored, particularly from a synthetic biology perspective. In this review, we summarize the state-of-the art strategies for constructing the highly repetitive genes encoding the protein polymers, and highlight the advanced approaches for metabolically engineering expression hosts towards high-level biosynthesis of the target protein polymers. Finally, we showcase the typical protein polymers utilized to fabricate delivery vehicles.

Delivering on the promise of recombinant silk-inspired proteins for drug delivery

Effective drug delivery is essential for the success of a medical treatment. Polymeric drug delivery systems (DDSs) are preferred over systemic administration of drugs due to their protection capacity, directed release, and reduced side effects. Among the numerous polymer sources, silks and recombinant silks have drawn significant attention over the past decade as DDSs. Native silk is produced from a variety of organisms, which are then used as sources or guides of genetic material for heterologous expression or engineered designs. Recombinant silks bear the outstanding properties of natural silk, such as processability in aqueous solution, self-assembly, drug loading capacity, drug stabilization/protection, and degradability, while incorporating specific properties beneficial for their success as DDS, such as monodispersity and tailored physicochemical properties. Moreover, the on-demand inclusion of sequences that customize the DDS for the specific application enhances efficiency. Often, inclusion of a drug into a DDS is achieved by simple mixing or diffusion and stabilized by non-specific molecular interactions; however, these interactions can be improved by the incorporation of drug-binding peptide sequences. In this review we provide an overview of native sources for silks and silk sequences, as well as the design and formulation of recombinant silk biomaterials as drug delivery systems in a variety of formats, such as films, hydrogels, porous sponges, or particles.

Progress in silk and silk fiber-inspired polymeric nanomaterials for drug delivery

The fields of drug and gene delivery have been revolutionized by the discovery and characterization of polymer-based materials. Polymeric nanomaterials have emerged as a strategy for targeted delivery because of features such as their impressive biocompatibility and improved availability. Use of naturally derived polymers in these nanomaterials is advantageous due to their biodegradability and bioresorption. Natural biopolymer-based particles composed of silk fibroins and other silk fiber-inspired proteins have been the focus of research in drug delivery systems due to their simple synthesis, tunable characteristics, and ability to respond to stimuli. Several silk and silk-inspired polymers contain a high proportion of reactive side groups, allowing for functionalization and addition of targeting moieties. In this review, we discuss the main classes of silk and silk-inspired polymers that are being used in the creation of nanomaterials. We also focus on the fabrication techniques used in generating a tunable design space of silk-based polymeric nanomaterials and detail how that translates into use for drug delivery to several distinct microenvironments.

Complexation of a Polypeptide-Polyelectrolytes Bioparticle as a Biomaterial of Antibacterial Activity

The development of biomaterials to enable application of antimicrobial peptides represents a strategy of high and current interest. In this study, a bioparticle was produced by the complexation between an antimicrobial polypeptide and the biocompatible and biodegradable polysaccharides chitosan-N-arginine and alginate, giving rise to a colloidal polyelectrolytic complex of pH-responsive properties. The inclusion of the polypeptide in the bioparticle structure largely increases the binding sites of complexation during the bioparticles production, leading to its effective incorporation. After lyophilization, detailed evaluation of colloidal structure of redispersed bioparticles evidenced nano or microparticles with size, polydispersity and zeta potential dependent on pH and ionic strength, and the dependence was not withdrawn with the polypeptide inclusion. Significant increase of pore edge tension in giant vesicles evidenced effective interaction of the polypeptide-bioparticle with lipid model membrane. Antibacterial activity against Aeromonas dhakensis was effective at 0.1% and equal for the isolated polypeptide and the same complexed in bioparticle, which opens perspectives to the composite material as an applicable antibacterial system.

Current research progress of local drug delivery systems based on biodegradable polymers in treating chronic osteomyelitis

Chronic osteomyelitis is one of the most challenging diseases in orthopedic treatment. It is usually treated with intravenous antibiotics and debridement in clinical practice, which also brings systemic drug side effects and bone defects. The local drug delivery system of antibiotics has the characteristics of targeted slow release to the lesion site, replacing systemic antibiotics and reducing the toxic and side effects of drugs. It can also increase the local drug concentration, achieve sound bacteriostatic effects, and promote bone healing and formation. Currently, PMMA beads are used in treating chronic osteomyelitis at home and abroad, but the chain beads need to be removed after a second operation, inconveniences patients. Biodegradable materials have been extensively studied as optimal options for antibiotic encapsulation and delivery, bringing new hope for treating chronic osteomyelitis. This article reviews the research progress of local drug delivery systems based on biodegradable polymers, including natural and synthetic ones, in treating chronic osteomyelitis.

Recombinant protein polymers as carriers of chemotherapeutic agents

Chemotherapy is the standard of care for the treatment of cancer and infectious diseases. However, its use is associated with severe toxicity and resistance arising mainly due to non-specificity, resulting in disease progression. The advancement in recombinant technology has led to the synthesis of genetically engineered protein polymers like Elastin-like polypeptide (ELP), Silk-like polypeptide (SLP), hybrid protein polymers with specific sequences to impart precisely controlled properties and to target proteins that have provided satisfactory preclinical outcomes. Such protein polymers have been exploited for the formulation and delivery of chemotherapeutics for biomedical applications. The use of such polymers has not only solved the limitation of conventional chemotherapy but has also improved the therapeutic index of typical drug delivery systems. This review, therefore, summarizes the development of such advanced recombinant protein polymers designed to deliver chemotherapeutics and also discusses the key challenges associated with their current usage and their application in the future.

Advancements in antimicrobial nanoscale materials and self-assembling systems

Antimicrobial resistance is directly responsible for more deaths per year than either HIV/AIDS or malaria and is predicted to incur a cumulative societal financial burden of at least $100 trillion between 2014 and 2050. Already heralded as one of the greatest threats to human health, the onset of the coronavirus pandemic has accelerated the prevalence of antimicrobial resistant bacterial infections due to factors including increased global antibiotic/antimicrobial use. Thus an urgent need for novel therapeutics to combat what some have termed the 'silent pandemic' is evident. This review acts as a repository of research and an overview of the novel therapeutic strategies being developed to overcome antimicrobial resistance, with a focus on self-assembling systems and nanoscale materials. The fundamental mechanisms of action, as well as the key advantages and disadvantages of each system are discussed, and attention is drawn to key examples within each field. As a result, this review provides a guide to the further design and development of antimicrobial systems, and outlines the interdisciplinary techniques required to translate this fundamental research towards the clinic.

Bioengineering of spider silks for the production of biomedical materials

Spider silks are well known for their extraordinary mechanical properties. This characteristic is a result of the interplay of composition, structure and self-assembly of spider silk proteins (spidroins). Advances in synthetic biology have enabled the design and production of spidroins with the aim of biomimicking the structure-property-function relationships of spider silks. Although in nature only fibers are formed from spidroins, in vitro, scientists can explore non-natural morphologies including nanofibrils, particles, capsules, hydrogels, films or foams. The versatility of spidroins, along with their biocompatible and biodegradable nature, also placed them as leading-edge biological macromolecules for improved drug delivery and various biomedical applications. Accordingly, in this review, we highlight the relationship between the molecular structure of spider silk and its mechanical properties and aims to provide a critical summary of recent progress in research employing recombinantly produced bioengineered spidroins for the production of innovative bio-derived structural materials.

Nanotechnology in the Diagnosis and Treatment of Osteomyelitis

Infection remains one of the largest threats to global health. Among those infections that are especially troublesome, osteomyelitis, or inflammation of the bone, typically due to infection, is a particularly difficult condition to diagnose and treat. This difficulty stems not only from the biological complexities of opportunistic infections designed to avoid the onslaught of both the host immune system as well as exogenous antibiotics, but also from changes in the host vasculature and the heterogeneity of infectious presentations. While several groups have attempted to classify and stage osteomyelitis, controversy remains, often delaying diagnosis and treatment. Despite a host of preclinical treatment advances being incubated in academic and company research and development labs worldwide, clinical treatment strategies remain relatively stagnant, including surgical debridement and lengthy courses of intravenous antibiotics, both of which may compromise the overall health of the bone and the patient. This manuscript reviews the current methods for diagnosing and treating osteomyelitis and then contemplates the role that nanotechnology might play in the advancement of osteomyelitis treatment.