Advanced Thermoactive Nanomaterials for Thermomedical Tissue Regeneration: Opportunities and Challenges

Nanomaterials usually possess remarkable properties, including excellent biocompatibility, unique physical and chemical characteristics, and bionic attributes, which make them highly promising for applications in tissue regeneration. Thermal therapy has emerged as a versatile approach for wound healing, nerve repair, bone regeneration, tumor therapy, and antibacterial tissue regeneration. By combining nanomaterials with thermal therapy, multifunctional nanomaterials with thermogenic effects and tissue regeneration capabilities can be engineered to achieve enhanced therapeutic outcomes. This study provides a comprehensive review of the effects of thermal stimulation on cellular and tissue regeneration. Furthermore, it highlights the applications of photothermal, magnetothermal, and electrothermal nanomaterials, and thermally responsive drug delivery systems in tissue engineering. In Addition, the bioactivities and biocompatibilities of several representative thermal nanomaterials are discussed. Finally, the challenges facing thermal nanomaterials are outlined, and future prospects in the field are presented with the aim of offering new opportunities and avenues for the utilization of thermal nanomaterials in tissue regeneration.

Charge-Reversal Nano-Drug Delivery Systems in the Tumor Microenvironment: Mechanisms, Challenges, and Therapeutic Applications

The charge-reversal nano-drug delivery system (CRNDDS) is a promising system for delivering chemotherapy drugs and has gained widespread application in cancer treatment. In this review, we summarize the recent advancements in CRNDDSs in terms of cancer treatment. We also delve into the charge-reversal mechanism of the CRNDDSs, focusing on the acid-responsive, redox-responsive, and enzyme-responsive mechanisms. This study elucidates how these systems undergo charge transitions in response to specific microenvironmental stimuli commonly found in tumor tissues. Furthermore, this review explores the pivotal role of CRNDDSs in tumor diagnosis and treatment, and their potential limitations. By leveraging the unique physiological characteristics of tumors, such as the acidic pH, specific redox potential, and specific enzyme activity, these systems demonstrate enhanced accumulation and penetration at tumor sites, resulting in improved therapeutic efficacy and diagnostic accuracy. The implications of this review highlight the potential of charge-reversal drug delivery systems as a novel and targeted strategy for cancer therapy and diagnosis.

Wound microenvironment-responsive peptide hydrogel with multifunctionalities for accelerating wound healing

The fabrication of wound microenvironment-responsive peptide hydrogels with hemostatic ability, antibacterial activity, and wound healing potential remains a challenge. Herein, we constructed a multifunctional dressing by inducing the self-assembly of a peptide (Pep-1) and water-soluble new methylene blue (NMB) through electrostatic interaction. The self-assembly mechanism was demonstrated using a combination of transmission electron microscopy, circular dichroism spectrum, fluorescence spectrum, Zeta potential, and rheological analysis. The Pep-1/NMB hydrogel also exhibited a faster drug release rate in wound acidic environment. Furthermore, when Pep-1/NMB was exposed to a 635 nm laser, its antibacterial ratios increased sharply to 95.3%, indicating remarkably improved antibacterial effects. The findings from the blood coagulation and hemostasis assay indicated that Pep-1/NMB effectively enhanced the speed of blood clotting in vitro and efficiently controlled hemorrhage in a mouse liver hemorrhage model. Meanwhile, hemolytic and cytotoxicity evaluation revealed that the hydrogel had excellent hemocompatibility and cytocompatibility. Finally, the findings from the wound healing studies and H&E staining indicated that the Pep-1/NMB hydrogel had a significant impact on cell migration and wound repair. The results indicated that wound microenvironment-responsive Pep-1/NMB hydrogel had significant potential as a highly effective wound dressing platform, offering rapid hemostasis, antibacterial, and wound healing acceleration properties.

Review of NIR-responsive ''Smart'' carriers for photothermal chemotherapy

This review focuses on the versatile applications of near-infrared (NIR)-responsive smart carriers in biomedical applications, particularly drug delivery and photothermal chemotherapy. These carriers demonstrate multi-responsive theranostics capabilities, including pH-dependent drug release, targeted delivery of chemotherapeutics, heat-mediated drug release, and photothermal tumor damage. Biological samples are transparent to NIR light with a suitable wavelength, and therefore, NIR light is advantageous for deep-tissue penetration. It also generates sufficient heat in tissue samples, which is beneficial for on-demand NIR-responsive drug delivery in vivo systems. The development of biocompatible materials with sufficient NIR light absorption properties and drug-carrying functionality has shown tremendous growth in the last five years. Thus, this review offers insights into the current research development of NIR-responsive materials with therapeutic potential and prospects aimed at overcoming challenges to improve the therapeutic efficacy and safety in the dynamic field of NIR-responsive drug delivery.

Emerging strategies for combating Fusobacterium nucleatum in colorectal cancer treatment: Systematic review, improvements and future challenges

Colorectal cancer (CRC) is generally characterized by a high prevalence of Fusobacterium nucleatum (F. nucleatum), a spindle-shaped, Gram-negative anaerobe pathogen derived from the oral cavity. This tumor-resident microorganism has been closely correlated with the occurrence, progression, chemoresistance and immunosuppressive microenvironment of CRC. Furthermore, F. nucleatum can specifically colonize CRC tissues through adhesion on its surface, forming biofilms that are highly resistant to commonly used antibiotics. Accordingly, it is crucial to develop efficacious non-antibiotic approaches to eradicate F. nucleatum and its biofilms for CRC treatment. In recent years, various antimicrobial strategies, such as natural extracts, inorganic chemicals, organic chemicals, polymers, inorganic-organic hybrid materials, bacteriophages, probiotics, and vaccines, have been proposed to combat F. nucleatum and F. nucleatum biofilms. This review summarizes the latest advancements in anti-F. nucleatum research, elucidates the antimicrobial mechanisms employed by these systems, and discusses the benefits and drawbacks of each antimicrobial technology. Additionally, this review also provides an outlook on the antimicrobial specificity, potential clinical implications, challenges, and future improvements of these antimicrobial strategies in the treatment of CRC.

The Advances and Biomedical Applications of Imageable Nanomaterials

Nanomedicine shows great potential in screening, diagnosing and treating diseases. However, given the limitations of current technology, detection of some smaller lesions and drugs’ dynamic monitoring still need to be improved. With the advancement of nanotechnology, researchers have produced various nanomaterials with imaging capabilities which have shown great potential in biomedical research. Here, we summarized the researches based on the characteristics of imageable nanomaterials, highlighted the advantages and biomedical applications of imageable nanomaterials in the diagnosis and treatment of diseases, and discussed current challenges and prospects.

Caging and photo-triggered uncaging of singlet oxygen by excited state engineering of electron donor-acceptor-linked molecular sensors

Singlet oxygen (¹O₂), one of the most sought-after species in oxidative chemical reactions and photodynamic cancer therapy, is activated and neutralized in the atmosphere and living cells. It is essential to see "when" and "where" ¹O₂ is produced and delivered to understand and utilize it. There is an increasing demand for molecular sensor tools to capture, store, and supply ¹O₂, controlled by light and engineered singlet and triplet states, indicating the ¹O₂-capturing-releasing state. Here, we demonstrate the outstanding potential of an aminocoumarin-methylanthracene-based electron donor–acceptor molecule (1). Spectroscopic measurements confirm the formation of an endoperoxide (1-O₂) which is not strongly fluorescent and remarkably different from previously reported ¹O₂ sensor molecules. Moreover, the photoexcitation on the dye in 1-O₂ triggers fluorescence enhancement by the oxidative rearrangement and a competing ¹O₂ release. The unique ability of 1 will pave the way for the spatially and temporally controlled utilization of ¹O₂ in various areas such as chemical reactions and phototherapies.

Polymeric Delivery of Therapeutic Nucleic Acids

The advent of genome editing has transformed the therapeutic landscape for several debilitating diseases, and the clinical outlook for gene therapeutics has never been more promising. The therapeutic potential of nucleic acids has been limited by a reliance on engineered viral vectors for delivery. Chemically defined polymers can remediate technological, regulatory, and clinical challenges associated with viral modes of gene delivery. Because of their scalability, versatility, and exquisite tunability, polymers are ideal biomaterial platforms for delivering nucleic acid payloads efficiently while minimizing immune response and cellular toxicity. While polymeric gene delivery has progressed significantly in the past four decades, clinical translation of polymeric vehicles faces several formidable challenges. The aim of our Account is to illustrate diverse concepts in designing polymeric vectors towards meeting therapeutic goals of in vivo and ex vivo gene therapy. Here, we highlight several classes of polymers employed in gene delivery and summarize the recent work on understanding the contributions of chemical and architectural design parameters. We touch upon characterization methods used to visualize and understand events transpiring at the interfaces between polymer, nucleic acids, and the physiological environment. We conclude that interdisciplinary approaches and methodologies motivated by fundamental questions are key to designing high-performing polymeric vehicles for gene therapy.

Self-Assembled Organic Nanomaterials for Drug Delivery, Bioimaging, and Cancer Therapy

Over the past few decades, tremendous progress has been made in the development of engineering nanomaterials, which opened new horizons in the field of diagnosis and treatment of various diseases. In particular, self-assembled organic nanomaterials with intriguing features including delicate structure tailoring, facile processability, low cost, and excellent biocompatibility have shown outstanding potential in biomedical applications because of the enhanced permeability and retention (EPR) effect and multifunctional properties. In this review, we briefly introduce distinctive merits of self-assembled organic nanomaterials for biomedical applications. The main focus will be placed on summarizing recent advances in self-assembled organic nanomedicine for drug delivery, bioimaging, and cancer phototherapy, followed by highlighting a critical perspective on further development of self-assembled organic nanomaterials for future clinical translation. We believe that the above themes will appeal to researchers from different fields, including material, chemical, and biological sciences, as well as pharmaceutics.

Stimuli-Responsive Materials for Tissue Engineering and Drug Delivery

Smart or stimuli-responsive materials are an emerging class of materials used for tissue engineering and drug delivery. A variety of stimuli (including temperature, pH, redox-state, light, and magnet fields) are being investigated for their potential to change a material's properties, interactions, structure, and/or dimensions. The specificity of stimuli response, and ability to respond to endogenous cues inherently present in living systems provide possibilities to develop novel tissue engineering and drug delivery strategies (for example materials composed of stimuli responsive polymers that self-assemble or undergo phase transitions or morphology transformations). Herein, smart materials as controlled drug release vehicles for tissue engineering are described, highlighting their potential for the delivery of precise quantities of drugs at specific locations and times promoting the controlled repair or remodeling of tissues.

Biomaterial-assisted photoimmunotherapy for cancer

The biomaterials have been well designed as photoabsorbing/sensitizing agents or effective carriers to enhance the photoimmunotherapeutic efficacy and evade their side effects.

Co-delivery of chlorin e6 and doxorubicin using PEGylated hollow nanocapsules for ‘all-in-one’ tumor theranostics

Aim: Hollow mesoporous copper sulfide nanocapsules conjugated with poly(ethylene glycol) (PEG), doxorubicin and chlorin e6 (HPDC) were synthesized for fluorescence imaging and multimodal tumor therapy. Materials & methods: HPDC were synthesized by encapsulating chlorin e6 and doxorubicin into PEGylated nanocapsules via a simple precipitation method. The photothermal/photodynamic effects, drug release, cellular uptake, imaging capacities and antitumor effects of the HPDCs were evaluated. Results: This smart nanoplatform is stimulus-responsive toward an acidic microenvironment and near infrared laser irradiation. Moreover, fluorescence imaging-guided and combined photothermal/photodynamic/chemotherapies of tumors were promoted under laser activation and led to efficient tumor ablation, as evidenced by exploring animal models in vivo. Conclusion: HPDCs are expected to serve as potent and reliable nanoagents for achieving superior therapeutic outcomes in cancer management.

Click and photo-release dual-functional nucleic acid nanostructures

We functionalize nucleic acid nanostructures with click chemistry (for attachment of cargos) and a photocleavable linker (for release). We demonstrate cargo attachment using a fluorescein dye and release using UV trigger from an RNA three-way junction, a DNA star motif and a DNA tetrahedron. Such multifunctional nucleic acid nanostructures have potential in targeted drug delivery.

Photoresponsive Drug/Gene Delivery Systems

Light as an external stimulus can be precisely manipulated in terms of irradiation time, site, wavelength, and density. As such, photoresponsive drug/gene delivery systems have been increasingly pursued and utilized for the spatiotemporal control of drug/gene delivery to enhance their therapeutic efficacy and safety. In this review, we summarized the recent research progress on photoresponsive drug/gene delivery, and two major categories of delivery systems were discussed. The first category is the direct responsive systems that experience photoreactions on the vehicle or drug themselves, and different materials as well as chemical structures responsive to UV, visible, and NIR light are summarized. The second category is the indirect responsive systems that require a light-generated mediator signal, such as heat, ROS, hypoxia, and gas molecules, to cascadingly trigger the structural transformation. The future outlook and challenges are also discussed at the end.

Gas-Stabilizing Gold Nanocones for Acoustically Mediated Drug Delivery

The efficient penetration of drugs into tumors is a major challenge that remains unmet. Reported herein is a strategy to promote extravasation and enhanced penetration using inertial cavitation initiated by focused ultrasound and cone-shaped gold nanoparticles that entrap gas nanobubbles. The cones are capable of initiating inertial cavitation under pressures and frequencies achievable with existing clinical ultrasound systems and of promoting extravasation and delivery of a model large therapeutic molecule in an in vitro tissue mimicking flow phantom, achieving penetration depths in excess of 2 mm. Ease of functionalization and intrinsic imaging capabilities provide gold with significant advantages as a material for biomedical applications. The cones show neither cytotoxicity in Michigan Cancer Foundation (MCF)-7 cells nor hemolytic activity in human blood at clinically relevant concentrations and are found to be colloidally stable for at least 5 d at 37 °C and several months at 4 °C.

Selective cancer treatment via photodynamic sensitization of hypoxia-responsive drug delivery

The precise and selective delivery of chemodrugs into tumors represents a critical requirement for anti-cancer therapy. Intelligent delivery systems that are responsive to a single internal or external stimulus often lack sufficient cancer selectivity, which compromises the drug efficacy and induces undesired side effects. To overcome this dilemma, we herein report a cancer-targeting vehicle which allows highly cancer-selective drug release in response to cascaded external (light) and internal (hypoxia) dual triggers. In particular, doxorubicin (DOX)-loaded, hypoxia-dissociable nanoparticles (NPs) were prepared from self-assembled polyethylenimine-nitroimidazole (PEI-NI) micelles that were further co-assembled with hyaluronic acid-Ce6 (HC). Upon accumulation in tumor cells, tumor site-specific light irradiation (660 nm, 10 mW cm^-2) generated high levels of reactive oxygen species (ROS) and greatly enhanced the hypoxic levels to induce NP dissociation and accordingly DOX release. A synergistic anti-cancer efficacy between DOX-mediated chemotherapy and Ce6-mediated photodynamic therapy (PDT) was thus achieved, resulting in reduced side effects to normal tissues/cells. This study therefore provides an effective method to control the cancer-specific drug delivery by responding to cascaded multiple triggers, and it renders promising applications for the programmed combination of chemotherapy and PDT toward cancer treatment.

Mechanistic insight into the singlet oxygen-triggered expansion of hypoxia-responsive polymeric micelles

Singlet oxygen can trigger the oxidation of nitroimidazole-bearing micelles for on-demand cargo release.

Noninvasive rapid bacteria-killing and acceleration of wound healing through photothermal/photodynamic/copper ion synergistic action of a hybrid hydrogel

Bacterial infection often delays healing of wounded tissues and so it is essential to improve the antibacterial efficiency in situ.