Multifunctional Nanofibrous Scaffolds Capable of Localized Delivery of Theranostic Nanoparticles for Postoperative Cancer Management

Postoperative recovery of cancer patients can be affected by complications, such as tissue dysfunction or disability caused by tissue resection, and also cancer recurrence resulting from residual cancer cells. Despite impressive progress made for tissue engineering scaffolds that assist tissue regeneration for postoperative cancer patients, the majority of existing tissue engineering scaffolds still lack functions for monitoring and killing residual cancer cells, if there are any, upon their detection. In this study, multifunctional scaffolds that comprise biodegradable nanofibers and core-shell structured microspheres encapsulated with theranostic nanoparticles (NPs) are developed. The multifunctional scaffolds possess an extracellular matrix-like nanofibrous architecture and soft tissue-like mechanical properties, making them excellent tissue engineering patch candidates for assisting in the repair and regeneration of tissues at the cancerous sites after surgery. Furthermore, they are capable of localized delivery of theranostic NPs upon quick degradation of core-shell structured microspheres that contain theranostic NPs. Leveraging on folic acid-mediated ligand-receptor binding, surface-enhanced Raman scattering activity, and near-infrared-responsive photothermal effect of the theranostic gold NPs (AuNPs) delivered locally, the multifunctional scaffolds display excellent active targeting, diagnosis, and photothermal therapy functions for cancer cells, showing great promise for adaptive postoperative cancer management.

Single-Component Self-Healing Antibacterial Anti-Inflammatory Intracellular-Antioxidative Poly(itaconic acid-pluronic) Hydrogel for Rapid Repair of MRSA-Impaired Wound

The rapid healing and repair of multidrug-resistant bacteria infected wound is still a challenge in the field of wound surgery. It is an effective strategy to develop multifunctional bioactive biomaterials with anti-infection therapy and promoting tissue regeneration. However, most of conventional multifunctional wound healing biomaterials possess the complicated composition and fabrication procedure, which may limit their clinical transformation. Herein, we report a single-component multifunctional bioactive self-healing scaffold (itaconic acid-pluronic-itaconic acid) (FIA) with robust antibacterial antioxidant anti-inflammatory bioactivity for treating methicillin-resistant Staphylococcus aureus (MRSA) impaired wound. FIA scaffolds exhibited the temperature-responsive sol-gel behavior, good injectability, and broad-spectrum antibacterial activity (100% inhibition rate against S. aureus, E. coli, and MRSA). FIA possessed favorable hemocompatibility and cell compatibility and even stimulated the cellular proliferation. FIA could efficiently scavenge the intracellular reactive oxygen species (ROS), decrease the inflammation factors expression, promote endotheliocyte migration and blood tube formation, and reduce the M1 phenotype of macrophages in vitro. FIA could significantly clear the MRSA infection, speed up the MRSA-infected wound healing and rapid formation of the normal epithelial layer and skin appendages. This work may provide a simple and efficient multifunctional bioactive biomaterial strategy for overcoming the challenge of the MRSA-impaired wound.

Multifunctional Scaffolds Based on Emulsion and Coaxial Electrospinning Incorporation of Hydroxyapatite for Bone Tissue Regeneration

Tissue engineering is nowadays a powerful tool to restore damaged tissues and recover their normal functionality. Advantages over other current methods are well established, although a continuous evolution is still necessary to improve the final performance and the range of applications. Trends are nowadays focused on the development of multifunctional scaffolds with hierarchical structures and the capability to render a sustained delivery of bioactive molecules under an appropriate stimulus. Nanocomposites incorporating hydroxyapatite nanoparticles (HAp NPs) have a predominant role in bone tissue regeneration due to their high capacity to enhance osteoinduction, osteoconduction, and osteointegration, as well as their encapsulation efficiency and protection capability of bioactive agents. Selection of appropriated polymeric matrices is fundamental and consequently great efforts have been invested to increase the range of properties of available materials through copolymerization, blending, or combining structures constituted by different materials. Scaffolds can be obtained from different processes that differ in characteristics, such as texture or porosity. Probably, electrospinning has the greater relevance, since the obtained nanofiber membranes have a great similarity with the extracellular matrix and, in addition, they can easily incorporate functional and bioactive compounds. Coaxial and emulsion electrospinning processes appear ideal to generate complex systems able to incorporate highly different agents. The present review is mainly focused on the recent works performed with Hap-loaded scaffolds having at least one structural layer composed of core/shell nanofibers.

Bioactive Anti-Inflammatory Thermocatalytic Nanometal-Polyphenol Polypeptide Scaffolds for MRSA-Infection/Tumor Postsurgical Tissue Repair

Postsurgical tumor recurrence, infection, and tissue defect are still the challenges in clinical medicine. The development of multifunctional biomaterial scaffolds with a microenvironment-responsive tumor-infection therapy-tissue repair is highly desirable. Herein, we report a bioactive, injectable, adhesive, self-healing, antibacterial, and anti-inflammatory metal-polyphenol polypeptide nanocomposite scaffold (PEAPF) with temporal-spatial-controlled inflammation-triggered therapeutic properties for efficient infection and postsurgical tumor therapy and skin repair. PEAPF scaffolds showed sustained and inherent inflammation-triggered Fenton catalysis and mild thermochemical effect for specifically inhibiting tumor recurrence in vitro and in vivo. The PEAPF scaffolds significantly facilitated skin tissue regeneration in MRSA-infected chronic wounds and postsurgical tissue defects after tumor resection. This study presents the multifunctional scaffold-based safe and efficient therapeutic strategy to prevent local tumor recurrence and enhance postsurgical tissue regeneration.

Injectable self-healing ceria-based nanocomposite hydrogel with ROS-scavenging activity for skin wound repair

Excessive reactive oxygen species (ROS) in the injured skin may impede the wound repair and skin regeneration. Herein, we develop an injectable self-healing ceria-based nanocomposite hydrogel with ROS-scavenging activity to accelerate wound healing. The nanocomposite hydrogels were successfully prepared by coating cerium oxide nanorods with polyethylenimine and crosslinked with benzaldehyde-terminated F127 (F127-CHO) through the dynamic Schiff-base reaction (FVEC hydrogel). The results showed that the FVEC hydrogel possessed the good thermosensitivity, injectability, self-healing ability and ROS scavenging activity. The subcutaneous implantation experiments in mice confirmed that FVEC hydrogels are biocompatible and biodegradable in vivo. The full-thickness skin wound studies showed that FVEC hydrogel could significantly enhance the wound healing and epithelium regeneration with the formation of hair follicle and adipocyte tissue. This work provides a new strategy for the development of multifunctional Ce-based nanocomposite hydrogel for full-thickness skin wound healing and regeneration.

Self-Assembly and Mechanical Properties of Engineered Protein Based Multifunctional Nanofiber for Accelerated Wound Healing

The present work reports a new route for preparing tunable multifunctional biomaterials through the combination of synthetic biology and material chemistry. Genetically encoded catechol moiety is evolved in a nanofiber mat with defined surface and secondary reactive functional chemistry, which promotes self-assembly and wet adhesion property of the protein. The catechol moiety is further exploited for the controlled release of boric acid that provides a congenial cellular microenvironment for accelerated wound healing. The presence of 3,4-dihydroxyphenylalanine in the nanofiber mat act as a stimulus to trigger cell proliferation, migration, and vascularization to accelerate wound healing. Electron paramagnetic resonance, NMR, FTIR, and circular dichroism spectroscopy confirm the structural integrity, antioxidant property, and controlled release of boric acid. Fluorescent and scanning electron microscopy reveals the 3D architecture of nanofiber mat, which favors fibroblast growth, endothelial cell attachment, and tube formation, which are the desirable properties of a wound-healing material. Animal studies in the murine wound healing model assert that the multifunctional biomaterial significantly improve re-epithelialization and accelerate wound closure.

Present and future of tissue engineering scaffolds for dentin-pulp complex regeneration

More than two thirds of the global population suffers from tooth decay, which results in cavities with various levels of lesion severity. Clinical interventions to treat tooth decay range from simple coronal fillings to invasive root canal treatment. Pulp capping is the only available clinical option to maintain the pulp vitality in deep lesions, but irreversible pulp inflammation and reinfection are frequent outcomes for this treatment. When affected pulp involvement is beyond repair, the dentist has to perform endodontic therapy leaving the tooth non-vital and brittle. On-going research strategies have failed to overcome the limitations of existing pulp capping materials so that healthy and progressive regeneration of the injured tissues is attained. Preserving pulp vitality is crucial for tooth homeostasis and durability, and thus, there is a critical need for clinical interventions that enable regeneration of the dentin-pulp complex to rescue millions of teeth annually. The identification and development of appropriate biomaterials for dentin-pulp scaffolds are necessary to optimize clinical approaches to regenerate these hybrid dental tissues. Likewise, a deep understanding of the interactions between the micro-environment, growth factors, and progenitor cells will provide design basis for the most fitting scaffolds for this purpose. In this review, we first introduce the long-lasting clinical dental problem of rescuing diseased tooth vitality, the limitations of current clinical therapies and interventions to restore the damaged tissues, and the need for new strategies to fully revitalize the tooth. Then, we comprehensively report on the characteristics of the main materials of naturally-derived and synthetically-engineered polymers, ceramics, and composite scaffolds as well as their use in dentin-pulp complex regeneration strategies. Finally, we present a series of innovative smart polymeric biomaterials with potential to overcome dentin-pulp complex regeneration challenges.