Multifunctional Fe₃O₄@polydopamine core-shell nanocomposites for intracellular mRNA detection and imaging-guided photothermal therapy

Polydopamine-Based Biomaterials in Orthopedic Therapeutics: Properties, Applications, and Future Perspectives

Polydopamine is a versatile and modifiable polymer, known for its excellent biocompatibility and adhesiveness. It can also be engineered into a variety of nanoparticles and biomaterials for drug delivery, functional modification, making it an excellent choice to enhance the prevention and treatment of orthopedic diseases. Currently, the application of polydopamine biomaterials in orthopedic disease prevention and treatment is in its early stages, despite some initial achievements. This article aims to review these applications to encourage further development of polydopamine for orthopedic therapeutic needs. We detail the properties of polydopamine and its biomaterial types, highlighting its superior performance in functional modification on nanoparticles and materials. Additionally, we also explore the challenges and future prospects in developing optimal polydopamine biomaterials for clinical use in orthopedic disease prevention and treatment.

Metal-Coordinated Polydopamine Structures for Tumor Imaging and Therapy

Meticulously engineered nanomaterials achieve significant advances in the diagnosis and therapy of solid tumors by improving tumor delivery efficiency; and thereby, enhancing imaging and therapeutic efficacy. Currently, polydopamine (PDA) attracts widespread attention because of its biocompatibility, simplicity of preparation, abundant surface groups, and high photothermal conversion efficiency, which can be applied in drug delivery, photothermal therapy, theranostics, and other nanomedicine fields. Inspired by PDA structures that are rich in catechol and amino functional groups that can coordinate with various metal ions, which have charming qualities and characteristics, metal-coordinated PDA structures are exploited for tumor theranostics, but are not thoroughly summarized. Herein, this review summarizes the recent progress in the fabrication of metal-coordinated PDA structures and their availabilities in tumor imaging and therapy, with further in-depth discussion of the challenges and future perspectives of metal-coordinated PDA structures, with the aim that this systematic review can promote interdisciplinary intersections and provide inspiration for the further growth and clinical translation of PDA materials.

A novel nanodrug for the sensitization of photothermal chemotherapy for breast cancer in vitro

Owing to the complexity of tumor treatment, clinical tumor treatment has evolved from a single treatment mode to multiple combined treatment modes. Reducing the tolerance of tumors to heat and the toxicity of chemotherapy drugs to the body, as well as increasing the sensitivity of tumors to photothermal therapy and chemotherapy drugs, are key issues that urgently need to be addressed in the current cancer treatment. In this work, polylactic acid-based drug nanoparticles (PLA@DOX/GA/ICG) were synthesized with good photothermal conversion ability by encapsulating the water-soluble anticancer drug doxorubicin (DOX), photothermal conversion agent indocyanine green (ICG) and liposoluble drug gambogic acid (GA) using a double emulsion method. The preparation process of PLA@DOX/GA/ICG was examined. Gambogic acid entrapped in PLA@DOX/GA/ICG nanoparticles could act as an HSP90 protein inhibitor to achieve bidirectional sensitization to chemotherapy and photothermal therapy under 808 nm laser irradiation for the first time, effectively ablating breast cancer cells in vitro. This nanodrug was expected to be used for the efficient treatment of tumors.

Construct a Magnetic Pt/Ru Alloy Peroxidase Mimic As a Reusable and Cost-Effective "Signal-Off" Sensing Platform for Sensitive and Wide-Linear-Range Assay

"Signal-off" nanozyme sensing platforms are usually employed to detect analytes (e.g., ascorbic acid (AA) and alkaline phosphatase (ALP)), which are mostly based on oxidase (OXD) nanozymes. However, their drawbacks, like dissolved oxygen-dependent catalysis capability, relatively low enzyme activity, limited amount, and kind, may not favor sensing platforms' optimization. Meanwhile, with the need for sustainable development, a reusable "signal-off" sensing platform is essential for cutting down the cost of the assay, but it is rarely developed in previous studies. Magnetic peroxidase (POD) nanozymes potentially make up the deficiencies and become reusable and better "signal-off" sensing platforms. As a proof of concept, we first construct Fe3O4@polydopamine-supported Pt/Ru alloy nanoparticles (IOP@Pt/Ru) without stabilizers. IOP@Pt/Ru shows high POD activity with Vmax of 83.24 × 10-8 M·s-1 for 3,3',5,5'-Tetramethylbenzidine (TMB) oxidation. Meanwhile, its oxidation rate for TMB is slower than the reduction of oxidized TMB by reducers, favorable for a more significant detection signal. On the other hand, IOP@Pt/Ru possesses great magnet-responsive capability, making itself be recycled and reused for at least 15-round catalysis. When applying IOP@Pt/Ru for AA (ALP) detection, it performs better detectable adaptability, with a linear range of 0.01-0.2 mM (0.1-100 U/L) and a limit of detection of 0.01 mM (0.05 U/L), superior to most of OXD nanozyme-based ALP sensing platform. Finally, IOP@Pt/Ru's reusable assay was demonstrated in real blood samples for ALP assay, which has never been explored in previous studies. Overall, this study develops a reusable "signal-off" nanozyme sensing platform with superior assay capabilities than traditional OXD nanozymes, paves a new way to optimize nanozyme-based "signal-off" sensing platforms, and provides an idea for constructing inexpensive and sustainable sensing platforms.

Effect of Polymer and Cell Membrane Coatings on Theranostic Applications of Nanoparticles: A Review

The recent decade has witnessed a remarkable surge in the field of nanoparticles, from their synthesis, characterization, and functionalization to diverse applications. At the nanoscale, these particles exhibit distinct physicochemical properties compared to their bulk counterparts, enabling a multitude of applications spanning energy, catalysis, environmental remediation, biomedicine, and beyond. This review focuses on specific nanoparticle categories, including magnetic, gold, silver, and quantum dots (QDs), as well as hybrid variants, specifically tailored for biomedical applications. A comprehensive review and comparison of prevalent chemical, physical, and biological synthesis methods are presented. To enhance biocompatibility and colloidal stability, and facilitate surface modification and cargo/agent loading, nanoparticle surfaces are coated with different synthetic polymers and very recently, cell membrane coatings. The utilization of polymer- or cell membrane-coated nanoparticles opens a wide variety of biomedical applications such as magnetic resonance imaging (MRI), hyperthermia, photothermia, sample enrichment, bioassays, drug delivery, etc. With this review, the goal is to provide a comprehensive toolbox of insights into polymer or cell membrane-coated nanoparticles and their biomedical applications, while also addressing the challenges involved in translating such nanoparticles from laboratory benchtops to in vitro and in vivo applications. Furthermore, perspectives on future trends and developments in this rapidly evolving domain are provided.

A target-triggered strand displacement-assisted target recycling based on carbon dots-based fluorescent probe and MSNs@PDA nanoparticles for miRNA amplified detection and fluorescence imaging

A target-triggered strand displacement-assisted target recycling based on carbon dots-based fluorescent probe and mesoporous silica nanoparticles@polydopamine (MSNs@PDA) was established to detect miRNA. The surface of MSNs rich in mesopores was coated with a layer of PDA, which can adsorb and quench the fluorescence of single-stranded Fuel DNA with fluorescent carbon dots (CDs) modified at the end through fluorescence resonance energy transfer (FRET). After adding double-stranded DNA-gold nanoparticles (dsDNA-AuNPs) and target let-7a, it will trigger two toehold-mediated strand displacement reactions (TSDR), leading to the recovery of fluorescence and the recycling of target let-7a (excitation wavelength: 380 nm; emission wavelength: 458 nm). The recovery value of fluorescence is proportional to the logarithm of the target microRNA let-7a concentration, thus realizing the sensitivity amplification detection of disease markers. The MSNs@PDA@Fuel DNA-CDs/dsDNA-AuNPs nanoplatform based on the strategy of "on-off-on" and TSDR cyclic amplification may hold great potential as an effective and safe nanoprobe for accurate fluorescence imaging of diseases related to miRNA with low abundances.

Shape-Regulated Photothermal-Catalytic Tumor Therapy Using Polydopamine@Pt Nanozymes with the Elicitation of an Immune Response

Recently, nanozyme-based photothermal-catalytic therapy has emerged as a promising strategy for antitumor treatment. Extensive research has focused on optimizing the catalytic activity and photothermal conversion performance of nanozymes through size, morphology, and surface property regulations. However, the biological effects of nanozymes, such as cellular uptake and cytotoxicity, resulting from their physicochemical properties, remain largely unexplored. In this study, two types of polydopamine/platinum (PDA@Pt) nanozymes, flower-like (FPDA@Pt) and mesoporous spherical-like (MPDA@Pt), to comprehensively compare their enzyme-mimicking activity, photothermal conversion capacity, and antitumor efficiency are designed. These findings revealed that FPDA@Pt exhibited superior peroxidase-like activity and higher photothermal conversion efficiency compared to MPDA@Pt. This led to enhanced production of reactive oxygen species (ROS) and increased heat generation at tumor sites. Importantly, it is observed thatthe flower-like structure of FPDA@Pt facilitated enhanced cellular uptake, leading to an increased accumulation of nanozymes within tumor cells. Furthermore, the light irradiation on tumors also triggered a series of anti-tumor immune responses, further enhancing the therapeutic efficacy. This work provides a possible design orientation for nanozyme-based photothermal-catalytic tumor therapy, highlighting the importance of considering the physicochemical properties of nanozymes to optimize their therapeutic potential in antitumor strategies.

Adhesion molecule-targeted magnetic particle imaging nanoprobe for visualization of inflammation in acute lung injury

PURPOSE

Uncontrolled intra-alveolar inflammation is a central pathogenic feature, and its severity translates into a valid prognostic indicator of acute lung injury (ALI). Unfortunately, current clinical imaging approaches are unsuitable for visualizing and quantifying intra-alveolar inflammation. This study aimed to construct a small-sized vascular cell adhesion molecule-1 (VCAM-1)-targeted magnetic particle imaging (MPI) nanoprobe (ESPVPN) to visualize and accurately quantify intra-alveolar inflammation at the molecular level.

METHODS

ESPVPN was engineered by conjugating a peptide (VHPKQHRGGSK(Cy7)GC) onto a polydopamine-functionalized superparamagnetic iron oxide core. The MPI performance, targeting, and biosafety of the ESPVPN were characterized. VCAM-1 expression in HUVECs and mouse models was evaluated by western blot. The degree of inflammation and distribution of VCAM-1 in the lungs were assessed using histopathology. The expression of pro-inflammatory markers and VCAM-1 in lung tissue lysates was measured using ELISA. After intravenous administration of ESPVPN, MPI and CT imaging were used to analyze the distribution of ESPVPN in the lungs of the LPS-induced ALI models.

RESULTS

The small-sized (~10 nm) ESPVPN exhibited superior MPI performance compared to commercial MagImaging® and Vivotrax, and ESPVPN had effective targeting and biosafety. VCAM-1 was highly expressed in LPS-induced ALI mice. VCAM-1 expression was positively correlated with the LPS-induced dose (R = 0.9381). The in vivo MPI signal showed positive correlations with both VCAM-1 expression (R = 0.9186) and representative pro-inflammatory markers (MPO, TNF-α, IL-6, IL-8, and IL-1β, R > 0.7).

CONCLUSION

ESPVPN effectively targeted inflammatory lungs and combined the advantages of MPI quantitative imaging to visualize and evaluate the degree of ALI inflammation.

MgO@polydopamine Nanoparticle-Loaded Photothermal Microneedle Patches Combined with Chitosan Gel Dressings for the Treatment of Infectious Wounds

As for wound drug delivery, microneedles (MNs) have attracted wide attention. However, while effective at increasing the depth of drug delivery, traditional MNs often have limited drug loads and have difficulty penetrating scabs on wounds. Herein, we develop a drug delivery system combining MgO@polydopamine (MgO@PDA) nanoparticle-loaded photothermal MN patches and chitosan (CS) gel to inhibit the formation of scabs and deliver sufficient drugs into deep tissue. When inserted into the wound, the MN system can keep the wound bed moist and weakly acidic to inhibit the formation of scabs and accelerate wound closure. The released MgO@PDA nanoparticles from both the tips and the backing layer, which immensely increase the drug load, continuously release Mg2+ in the moist, weakly acidic wound bed, promoting tissue migration and the formation of microvessels. MgO@PDA nanoparticles show excellent antibacterial activity under near-infrared irradiation synergized with the CS gel, and the PDA coating can also overcome the adverse effects of oxidative stress. Through in vitro and in vivo experiments, the MN system showed remarkable antibacterial, antioxidant, anti-inflammatory, and pro-angiogenic effects, indicating its potential in the treatment of infectious wounds.

Synergistic effect of photothermal and magnetic hyperthermia for in situ activation of Fenton reaction in tumor microenvironment for chemodynamic therapy

Traditional cancer treatments are ineffective and cause severe adverse effects. Thus, the development of chemodynamic therapy (CDT) has the potential for in situ catalysis of endogenous molecules into highly toxic species, which would then effectively destroy cancer cells. However, the shortage of high-performance nanomaterials hinders the broad clinical application of this approach. In present study, an effective therapeutic platform was developed using a simple hydrothermal method for the in-situ activation of the Fenton reaction within the tumor microenvironment (TME) to generate substantial quantities of •OH and ultimately destroy cancer cells, which could be further synergistically increased by photothermal therapy (PHT) and magnetic hyperthermia (MHT) aided by FeMoO4 nanorods (NRs). The produced FeMoO4 NRs were used as MHT/PHT and Fenton catalysts. The photothermal conversion efficiency of the FeMoO4 NRs was 31.75 %. In vitro and \ experiments demonstrated that the synergistic combination of MHT/PHT/CDT notably improved anticancer efficacy. This work reveals the significant efficacy of CDT aided by both photothermal and magnetic hyperthermia and offers a feasible strategy for the use of iron-based nanoparticles in the field of biomedical applications.

HOF-101-based dual-mode biosensor for photoelectrochemical/electrochemiluminescence detection and imaging of oxytetracycline

A unique hydrogen-bonded organic frameworks (HOF-101)-based photoelectrochemical (PEC) and electrochemiluminescence (ECL) dual-mode biosensor using polydopamine nanoparticles (PDAs) as quencher was constructed for ultrasensitive detection and imaging of oxytetracycline (OXY). In particular, HOF-101 was a superior ECL material and can be observed with the naked eye. Furthermore, it also had outstanding PEC signal, so HOF-101 was a new dual-signal material with excellent performance, thus it was explored to realize dual-mode detection. As the main component of natural melanin, PDAs not only had good biocompatibility, but also contained rich functional groups on the surface. Additionally, PDAs had excellent light absorption ability and poor conductivity, which made it the excellent photoquencher. In this work, PDAs were introduced on the surface of HOF-101 to quench its ECL and PEC signals by using the dual-aptamer sandwich method, achieving ultrasensitive detection of antibiotic OXY. Particularly for ECL detection, HOF-101 was firstly used to visually detect OXY. The detection range can reach 0.1 pM-100 nM, and the limit of detection (LOD) can reach 0.04 pM. This work showed a great contribution to the development of new ECL-PEC materials and ECL visualization analysis, which had outstanding application potential in the fields of food safety and biochemical analysis.

Renal clearable magnetic nanoparticles for magnetic resonance imaging and guided therapy

Magnetic resonance imaging (MRI) is a non-invasive, radiation-free imaging technique widely used for disease detection and therapeutic evaluation due to its infinite penetration depth. Magnetic nanoparticles (MNPs) have unique magnetic and physicochemical properties, making them ideal as contrast agents for MRI. However, the in vivo toxicity of MNPs, resulting from metal ion leakage and long-term accumulation in the reticuloendothelial system (RES), limits their clinical application. To overcome these challenges, there is considerable interest in the development of renal-clearable MNPs that can be completely cleared through the kidney, reducing retention time and potential toxic risks. In this review, we provide an overview of recent advancements in the development of renal-clearable MNPs for disease imaging and treatment. We discuss the factors influencing renal clearance, summarize the types of renal-clearable MNPs, their synthesis methods, and biomedical applications. This review aims to offer comprehensive information for the design and clinical translation of renal-clearable MNPs. This article is categorized under: Nanotechnology Approaches to Biology > Nanoscale Systems in Biology Diagnostic Tools > Biosensing.

Sensitization Strategies of Lateral Flow Immunochromatography for Gold Modified Nanomaterials in Biosensor Development

Gold nanomaterials have become very attractive nanomaterials for biomedical research due to their unique physical and chemical properties, including size dependent optical, magnetic and catalytic properties, surface plasmon resonance (SPR), biological affinity and structural suitability. The performance of biosensing and biodiagnosis can be significantly improved in sensitivity, specificity, speed, contrast, resolution and so on by utilizing multiple optical properties of different gold nanostructures. Lateral flow immunochromatographic assay (LFIA) based on gold nanoparticles (GNPs) has the advantages of simple, fast operation, stable technology, and low cost, making it one of the most widely used in vitro diagnostics (IVDs). However, the traditional colloidal gold (CG)-based LFIA can only achieve qualitative or semi-quantitative detection, and its low detection sensitivity cannot meet the current detection needs. Due to the strong dependence of the optical properties of gold nanomaterials on their shape and surface properties, gold-based nanomaterial modification has brought new possibilities to the IVDs: people have attempted to change the morphology and size of gold nanomaterials themselves or hybrid with other elements for application in LFIA. In this paper, many well-designed plasmonic gold nanostructures for further improving the sensitivity and signal output stability of LFIA have been summarized. In addition, some opportunities and challenges that gold-based LFIA may encounter at present or in the future are also mentioned in this paper. In summary, this paper will demonstrate some feasible strategies for the manufacture of potential gold-based nanobiosensors of post of care testing (POCT) for faster detection and more accurate disease diagnosis.

Progress of cell membrane-derived biomimetic nanovesicles for cancer phototherapy

In recent years, considerable attention has been given to phototherapy, including photothermal and photodynamic therapy to kill tumor cells by producing heat or reactive oxygen species (ROS). It has the high merits of noninvasiveness and limited drug resistance. To fully utilize this therapy, an extraordinary nanovehicle is required to target phototherapeutic agents in the tumor cells. Nanovesicles embody an ideal strategy for drug delivery applications. Cell membrane-derived biomimetic nanovesicles represent a developing type of nanocarrier. Combining this technique with cancer phototherapy could enable a novel strategy. Herein, efforts are made to describe a comprehensive overview of cell membrane-derived biomimetic nanovesicles for cancer phototherapy. The description in this review is mainly based on representative examples of exosome-derived biomimetic nanomedicine research, ranging from their comparison with traditional nanocarriers to extensive applications in cancer phototherapy. Additionally, the challenges and future prospectives for translating these for clinical application are discussed.

Polydopamine-coated hexagonal boron nitride-based electrochemical immunosensing of T-Tau as a marker of Alzheimer's disease

Alzheimer's disease (AD) is a complex pathological process that is one of the leading causes of dementia globally. The demand for diagnostic tools that are minimally invasive, timely, and accurate is on the rise. Total tau (T-Tau) protein in blood serum is a promising biomarker for predicting early-stage AD diagnosis. In this study, the hexagonal boron nitride (HBN) based immunosensor platform was developed to detect T-Tau in artificial blood serum. After the exfoliation of HBN, its surface was coated with polydopamine (PDA) in alkaline conditions. The Anti-T-Tau was immobilized on a hydrophilic nanocomposite surface using PDA's reactive catechol and quinone groups, eliminating the need for extra crosslinkers. The working electrode surface of the screen-printed carbon electrode (SPCE) was coated with HBN-PDA nanocomposite using the drop-casting method. The biofunctional surface was created by directly immobilizing Anti-T-Tau on the HBN-PDA nanocomposite-modified SPCE. The analytical performance of the HBN-PDA/Anti-T-Tau/T-Tau immunosensor in the presence of T-Tau isoforms was determined through electrochemical measurements. The linear detection range was 1-30 pg/mL with a detection limit of 0.42 pg/mL for T-Tau, which is suitable for detecting T-Tau in the blood serum.

Chitosan functionalized gold nanostars as a theranostic platform for intracellular microRNA detection and photothermal therapy

The development of a theranostic platform that integrates both diagnostic and therapeutic capabilities is in great need for precise and personalized medicine. Here, we present a novel nanoplatform (AuNS@CS-hpDNA) formulated by chitosan functionalized gold nanostar composites and further complexed with fluorescent hairpin DNA (hpDNA) probes for tumor-related miRNA imaging and photothermal therapy (PTT). The optimized AuNS@CS-hpDNA nanoplatform mediated efficient hpDNA probe loading and intracellular delivery. Subsequently, the cytosol transfer of the hpDNA probe enabled specific hybridization using the targeted miRNA, which triggered the recovery of fluorescence for the precise detection of biomarker miR21 in living cells and realized the distinguishing cancer cell line MCF-7 and normal cells. Meanwhile, the AuNS@CS-hpDNA nanoplatform exhibited excellent photothermal conversion properties, which induced efficient cancer cell killing under laser irradiation. Thus, the developed AuNS@CS-hpDNA nanoplatform could simultaneously realize the precise detection of cancer cells and accurately initiate efficient PTT, which represents a promising strategy for precise cancer therapy.

Dual-Responsive Turn-On T1 Imaging-Guided Mild Photothermia for Precise Apoptotic Cancer Therapy

Apoptosis has gained increasing attention in cancer therapy as an intrinsic signaling pathway, which leads to minimal leakage of waste products from a dying cell to neighboring normal cells. Among various stimuli to trigger apoptosis, mild hyperthermia is attractive but confronts limitations of non-specific heating and acquired resistance from elevated expression of heat shock proteins. Here, a dual-stimulation activated turn-on T1 imaging-based nanoparticulate system (DAS) is developed for mild photothermia (≈43 °C)-mediated precise apoptotic cancer therapy. In the DAS, a superparamagnetic quencher (ferroferric oxide nanoparticles, Fe3 O4 NPs) and a paramagnetic enhancer (Gd-DOTA complexes) are connected via the N6-methyladenine (m6 A)-caged, Zn2+ -dependent DNAzyme molecular device. The substrate strand of the DNAzyme contains one segment of Gd-DOTA complex-labeled sequence and another one of HSP70 antisense oligonucleotide. When the DAS is taken up by cancer cells, overexpressed fat mass and obesity-associated protein (FTO) specifically demethylates the m6 A group, thereby activating DNAzymes to cleave the substrate strand and simultaneously releasing Gd-DOTA complex-labeled oligonucleotides. The restored T1 signal from the liberated Gd-DOTA complexes lights up the tumor to guide the location and time of deploying 808 nm laser irradiation. Afterward, locally generated mild photothermia works in concert with HSP70 antisense oligonucleotides to promote apoptosis of tumor cells. This highly integrated design provides an alternative strategy for mild hyperthermia-mediated precise apoptotic cancer therapy.

Semiconducting Polymer Nanospherical Nucleic Acid Probe for Transcriptomic Imaging of Cancer Chemo-Immunotherapy

Real-time in vivo imaging of RNA can enhance the understanding of physio-pathological processes. However, most nucleic acid-based sensors have poor resistance to nucleases and limited photophysical properties, making them suboptimal for this purpose. To address this, a semiconducting polymer nanospherical nucleic acid probe (SENSE) for transcriptomic imaging of cancer immunity in living mice is developed. SENSE comprises a semiconducting polymer (SP) backbone covalently linked with recognition DNA strands, which are complemented by dye-labeled signal DNA strands. Upon detection of targeted T lymphocyte transcript (Gzmb: granzyme B), the signal strands are released, leading to a fluorescence enhancement correlated to transcript levels with superb sensitivity. The always-on fluorescence of the SP core also serves as an internal reference for tracking SENSE uptake in tumors. Thus, SENSE has the dual-signal channel that enables ratiometric imaging of Gzmb transcripts in the tumor of living mice for evaluating chemo-immunotherapy; moreover, it has demonstrated sensitivity and specificity comparable to flow cytometry and quantitative polymerase chain reaction,  yet offering a faster and simpler means of T cell detection in resected tumors. Therefore, SENSE represents a promising tool for in vivo RNA imaging.

Recent advances on the construction of long-wavelength emissive supramolecular coordination complexes for photo-diagnosis and therapy

Recently, metal-based drugs have attracted relentless interest in the biomedical field. However, their short excitation/emission wavelengths and unsatisfactory therapeutic efficiency limit their biological applications in vivo. Currently, the second near-infrared window (NIR-II, 1000-1700 nm) provides more accurate imaging and therapeutic options. Thus, there has been a constant focus on developing multifunctional NIR metal agents for imaging and therapy that have deeper tissue penetration. Fortunately, supramolecular coordination complexes (SCCs) formed by the coordination-driven self-assembly of NIR-II emissive ligands can address the above issues. Importantly, metal receptors with chemotherapeutic properties in SCCs can bind to luminescent ligands, thus becoming a versatile therapeutic platform for chemotherapy, imaging and phototherapy. In this context, we systematically summarize the evolution of NIR-II emissive SCCs for biomedical applications and discuss future challenges and prospects.

Polydopamine-Based Nanoprobes Application in Optical Biosensing

Polydopamine (PDA), the synthetic counterpart of melanin, is a widely investigated bio-inspired material for its chemical and photophysical properties, and in the last few years, bio-application of PDA and PDA-based materials have had a dramatic increase. In this review, we described PDA application in optical biosensing, exploring its multiple roles as a nanomaterial. In optical sensing, PDA can not only be used for its intrinsic fluorescent and photoacoustic properties as a probe: in some cases, a sample optical signal can be derived by melanin generation in situ or it can be enhanced in another material thanks to PDA modification. The various possibilities of PDA use coupled with its biocompatibility will indeed widen even more its application in optical bioimaging.

Advances in Intelligent Stimuli-Responsive Microneedle for Biomedical Applications

Microneedles (MNs) are a new type of drug delivery method that can be regarded as an alternative to traditional transdermal drug delivery systems. Recently, MNs have attracted widespread attention for their advantages of effectiveness, safety, and painlessness. However, the functionality of traditional MNs is too monotonous and limits their application. To improve the efficiency of disease treatment and diagnosis by combining the advantages of MNs, the concept of intelligent stimulus-responsive MNs is proposed. Intelligent stimuli-responsive MNs can exhibit unique biomedical functions according to the internal and external environment changes. This review discusses the classification and principles of intelligent stimuli-responsive MNs, such as magnet, temperature, light, electricity, reactive oxygen species, pH, glucose, and protein. This review also highlights examples of intelligent stimuli-responsive MNs for biomedical applications, such as on-demand drug delivery, tissue repair, bioimaging, detection and monitoring, and photothermal therapy. These intelligent stimuli-responsive MNs offer the advantages of high biocompatibility, targeted therapy, selective detection, and precision treatment. Finally, the prospects and challenges for the application of intelligent stimuli-responsive MNs are discussed.

Polydopamine-containing nano-systems for cancer multi-mode diagnoses and therapies: A review

Polydopamine (PDA) has fascinating properties such as inherent biocompatibility, simple preparation, strong near-infrared absorption, high photothermal conversion efficiency, and strong metal ion chelation, which have catalyzed extensive research in PDA-containing multifunctional nano-systems particularly for biomedical applications. Thus, it is imperative to overview synthetic strategies of various PDA-containing nanoparticles (NPs) for state-of-the-art cancer multi-mode diagnoses and therapies applications, and offer a timely and comprehensive summary. In this review, we will focus on the synthetic approaches of PDA NPs, and summarize the construction strategies of PDA-containing NPs with different structure forms. Additionally, the application of PDA-containing NPs in bioimaging such as photoacoustic imaging, fluorescence imaging, magnetic resonance imaging and other imaging modalities will be reviewed. We will especially offer an overview of their therapeutic applications in tumor chemotherapy, photothermal therapy, photodynamic therapy, photocatalytic therapy, sonodynamic therapy, radionuclide therapy, gene therapy, immunotherapy and combination therapy. At the end, the current trends, limitations and future prospects of PDA-containing nano-systems will be discussed. This review aims to provide guidelines for new scientists in the field of how to design PDA-containing NPs and what has been achieved in this area, while offering comprehensive insights into the potential of PDA-containing nano-systems used in cancer diagnosis and treatment.

Photothermal theranostics with glutathione depletion and enhanced reactive oxygen species generation for efficient antibacterial treatment

Drug-resistant bacteria caused by the abuse of antibiotics have brought great challenges to antimicrobial therapy. Herein an antibiotic-free polydopamine (PDA) modified metal-organic framework (PDA-FDM-23) with photothermal-enhanced chemodynamic effect was developed for synergistic antibacterial treatment. The PDA-FDM-23 antibacterial agent exhibited high peroxidase-like activity. Moreover, the process was significantly accelerated by consuming glutathione (GSH) to generate more efficient oxidizing Cu⁺. In addition, the photothermal therapy (PTT) derived from PDA improved the chemodynamic therapy (CDT) activity triggering a reactive oxygen species explosion. This PTT-enhanced CDT strategy illustrated 100% antibacterial efficiency against both Staphylococcus aureus and Escherichia coli. Cytotoxicity and hemolysis analyses fully demonstrated the excellent biocompatibility of PDA-FDM-23. Overall, our work highlighted the strong peroxidase catalytic activity, excellent GSH consumption and photothermal performance of PDA-FDM-23, providing a new strategy for antibiotic-free reactive oxygen species (ROS) synergistic sterilization.

Functionalized Magnetic Nanoparticles for NIR-Induced Photothermal Therapy of Potential Application in Cervical Cancer

Photothermal therapy (PTT) holds great promise for cancer treatment with its effective ablation of solid tumors. As the essential core point, photothermal agents (PTAs) with excellent photothermal properties and good biocompatibility could help to fulfill highly efficient PTT. Herein, a novel type of nanoplatform Fe₃O₄@PDA/ICG (FPI) nanoparticle (NP) was designed and synthesized, which was composed of magnetic Fe₃O₄ and near-infrared excitable indocyanine green via encapsulation of polydopamine. The FPI NPs showed spherical structures in shape with uniform distribution and good chemical stability. Under 793 nm laser irradiation, FPI NPs could generate hyperthermia of 54.1 °C and photothermal conversion efficiency of 35.21%. The low cytotoxicity of FPI NPs was further evaluated and confirmed on HeLa cells with a high survival rate (90%). Moreover, under laser irradiation (793 nm), FPI NPs showed effective photothermal therapeutic characteristics for HeLa cells. Therefore, FPI NPs, as one of the promising PTAs, have great potential in the field of PTT for tumor treatment.

Electrospinning Preparation, Structure, and Properties of Fe3O4/Tb(acac)3phen/Polystyrene Bifunctional Microfibers

Compared to single functional materials, multifunctional materials with magnetism and luminescence are more attractive and promising; Thus, it has become an important subject. In our work, bifunctional Fe₃O₄/Tb(acac)₃phen/polystyrene) microfibers with magnetic and luminescent properties (acac: acetylacetone, phen: 1,10-phenanthroline) were synthesized by simple electrospinning process. The doping of Fe₃O₄ and Tb(acac)₃phen made the fiber diameter larger. The surface of pure polystyrene microfibers and microfibers doped only with Fe₃O₄ nanoparticles were chapped similar to bark, whereas the surface of the microfibers was smoother after doping with Tb(acac)₃phen complexes. The luminescent properties of the composite microfibers were systematically studied in contrast to pure Tb(acac)₃phen complexes, including excitation and emission spectra, fluorescence dynamics, and the temperature dependence of intensity. Compared with the pure complexes, the thermal activation energy and thermal stability of composite microfiber was significantly improved, and the luminescence of the unit mass of Tb(acac)₃phen complexes in composite microfibers was stronger than that in pure Tb(acac)₃phen complexes. The magnetic properties of the composite microfibers were also investigated using hysteresis loops, and an interesting experimental phenomenon was found that the saturation magnetization of the composite microfibers gradually increased with the increase in the doping proportion of terbium complexes.

Macrophage Reprogramming via the Modulation of Unfolded Protein Response with siRNA-Loaded Magnetic Nanoparticles in a TAM-like Experimental Model

New therapeutic strategies are required in cancer therapy. Considering the prominent role of tumor-associated macrophages (TAMs) in the development and progression of cancer, the re-education of TAMs in the tumor microenvironment (TME) could represent a potential approach for cancer immunotherapy. TAMs display an irregular unfolded protein response (UPR) in their endoplasmic reticulum (ER) to endure environmental stress and ensure anti-cancer immunity. Therefore, nanotechnology could be an attractive tool to modulate the UPR in TAMs, providing an alternative strategy for TAM-targeted repolarization therapy. Herein, we developed and tested polydopamine-coupled magnetite nanoparticles (PDA-MNPs) functionalized with small interfering RNAs (siRNA) to downregulate the protein kinase R (PKR)-like ER kinase (PERK) expression in TAM-like macrophages derived from murine peritoneal exudate (PEMs). After the evaluation of the cytocompatibility, the cellular uptake, and the gene silencing efficiency of PDA-MNPs/siPERK in PEMs, we analyzed their ability to re-polarize in vitro these macrophages from M2 to the M1 inflammatory anti-tumor phenotype. Our results indicate that PDA-MNPs, with their magnetic and immunomodulator features, are cytocompatible and able to re-educate TAMs toward the M1 phenotype by PERK inhibition, a UPR effector contributing to TAM metabolic adaptation. These findings can provide a novel strategy for the development of new tumor immunotherapies in vivo.

Preparation of quasi-core/shell structured composite energetic materials to improve combustion performance

Composite explosives with fast reaction rate, high energy release efficiency, and remarkable combustion performance can be obtained by the interaction between homogeneous energetic materials and heterogeneous energetic materials and have broad application prospects. However, ordinary physical mixtures can easily cause separation between the components in the preparation process, which is not conducive to reflecting the advantages of composite materials. In this study, high-energy composite structured explosives with RDX modified by polydopamine as the core and PTFE/Al as the shell were prepared using a simple ultrasonic method. The study of morphology, thermal decomposition, heat release, and combustion performance demonstrated that the quasi-core/shell structured samples have higher exothermic energy, faster combustion rate, more stable combustion characteristics, and lower mechanical sensitivity than the physical mixture.

Parameters optimization of Fe3O4 NPs synthesis by Tamarindus indica leaf extract possessing both peroxidase as well as excellent dye removal activity

This study reports optimized conditions for the green synthesis of iron (II,III) oxide nanoparticles (Fe₃O₄ NPs) from Tamarindus indica (T. indica) leaf extract. The synthetic parameters like concentration of leaf extract, solvent system, buffer, electrolyte, pH, and time were optimized for Fe₃O₄ NPs synthesis. Fe₃O₄ NPs were obtained from the synthesis protocol by measuring size (80 ± 3 nm approx.), characteristics color changes, and an absorption peak between 270 nm and 280 nm using a UV-visible spectrophotometer, scanning electron microscope (SEM), and an energy dispersive X-ray spectrometer (EDS) study. Peroxidase activity was tested with 3,3,5,5-Tetramethylbenzidine (TMB) oxidation in the presence of hydrogen peroxide and dye removal activity was tested with malachite green (MG). The results indicated that the successful synthesis of Fe₃O₄ nanoparticles using aqueous leaf extract of T. indica is a practical alternative for biomedical applications due to its potent peroxidase activity and high dye removal capacity (about 93% with UV light and 55% with room light).

Polydopamine Nanomaterials for Overcoming Current Challenges in Cancer Treatment

In efforts to overcome current challenges in cancer treatment, multifunctional nanoparticles are attracting growing interest, including nanoparticles made with polydopamine (PDA). PDA is a nature-inspired polymer with a dark brown color. It has excellent biocompatibility and is biodegradable, offering a range of extraordinary inherent advantages. These include excellent drug loading capability, photothermal conversion efficiency, and adhesive properties. Though the mechanism of dopamine polymerization remains unclear, PDA has demonstrated exceptional flexibility in engineering desired morphology and size, easy and straightforward functionalization, etc. Moreover, it offers enormous potential for designing multifunctional nanomaterials for innovative approaches in cancer treatment. The aim of this work is to review studies on PDA, where the potential to develop multifunctional nanomaterials with applications in photothermal therapy has been demonstrated. Future prospects of PDA for developing applications in enhancing radiotherapy and/or immunotherapy, including for image-guided drug delivery to boost therapeutic efficacy and minimal side effects, are presented.

Synergistic antibacterial effect of multifunctional TiO2-X-based nanoplatform loading arginine and polydopamine for promoting infected wounds healing

The gas therapy of some endogenous signaling molecules to treat diseases has caused extensive research, among which NO gas has shown great potential in fighting infection with various pathogens, promoting wound healing, etc. Here, we propose a photothermal/photodynamic/NO synergistic antibacterial nanoplatform by loading L-arginine (LA) on mesoporous TiO₂ and then encapsulating it with polydopamine. The obtained TiO_2-x-LA@PDA nanocomposite possesses both the excellent photothermal effect and ROS generation ability of mesoporous TiO₂, and the release of nitric oxide (NO) from L-arginine under near-infrared (NIR) light irradiation, while the sealing layer of PDA could induce NIR-triggered NO controlled release. In vitro antibacterial experiments confirmed that the synergistic effect of TiO_2-x-LA@PDA nanocomposites has excellent antibacterial effects against Gram-negative and Gram-positive bacteria, while in vivo experiments showed that it has lower toxicity. It is worth noting that compared with the pure photothermal effect and ROS, the generated NO showed a better bactericidal effect, and NO had a better ability to promote wound healing. In conclusion, the developed TiO_2-x-LA@PDA nanoplatform can be used as a nanoantibacterial agent, which can be further explored in the related biomedical field of photothermal activation of multimodal combined antibacterial therapy.

Magnetic Response Combined with Bioactive Ion Therapy: A RONS-Scavenging Theranostic Nanoplatform for Thrombolysis and Renal Ischemia-Reperfusion Injury

Currently, the limited efficacy of antithrombotic treatments is attributed to the inadequacy of pure drugs and the low ability of drugs to target the thrombus site. More importantly, timely thrombolysis is essential to reduce the sequelae of cardiovascular disease, but ischemia-reperfusion injury (IRI) remains a major challenge that must be solved after blood flow recovery. Herein, a multifunctional therapeutic nanoparticle (NP) based on Fe₃O₄ and strontium ions encapsulated in mesoporous polydopamine was successfully constructed and then loaded with TNK-tPA (FeM@Sr-TNK NPs). The NPs (59.9 min) significantly prolonged the half-life of thrombolytic drugs, which was 3.04 times that of TNK (19.7 min), and they had good biological safety. The NPs were shown to pass through vascular models with different inner diameters, curvatures, and stenosis under magnetic targeting and to enable accurate diagnosis of thrombi by photoacoustic imaging. NPs combined with the magnetic hyperthermia technique were used to accelerate thrombolysis and quickly open blocked blood vessels. Then, renal IRI-induced functional metabolic disorder and tissue damage were evidently attenuated by scavenging toxic reactive oxygen and nitrogen species and through the protective effects of bioactive ion therapy, including reduced apoptosis, increased angiogenesis, and inhibited fibrosis. In brief, we constructed a multifunctional nanoplatform for integrating a "diagnosis-therapy-protection" approach to achieve comprehensive management from thrombus to renal IRI, promoting the advancement of related technologies.

Tetrahedral DNA Nanostructure-Engineered Paper-Based Sensor with an Enhanced Antifouling Ability for Photoelectrochemical Sensing

Herein, a newly designed two-in-one tetrahedral DNA (TDN) nanostructure with an antifouling surface and backbone-rigidified interfacial tracks was developed for highly sensitive and selective detection of miRNA-182-5p. The well-regulated TDN tracks were assembled onto the surface of the TiO₂/MIL-125-NH₂-functionalized paper electrode, which efficiently avoided the obstacle of DNA strand tangling and decreased the probability of suspension during the walking process, thus greatly promoting the moving efficiency of DNA walkers. More interestingly, the TDN-modified sensing interfaces demonstrated incomparable antifouling ability against protein samples and interfering miRNAs due to the strong hydrophilic capacity and special molecular conformations, which addressed the dilemma of low sensitivity from traditional antifouling coating strategies. As a proof of concept, the designed bifunctional tetrahedron-modified paper-based photoelectrochemical sensor was successfully used to quantify miRNA-182-5p with a low detection limit of 0.09 fM and high specificity and was validated for monitoring of miRNA-182-5p in real samples. This TDN-engineered biointerface could be used as a universal platform for tracking various targets by substituting the biorecognition events, providing great promise for bioanalysis and clinical diagnosis.

Superhydrophobic aerogel blanket with magnetic and solar heating effect enables efficient continuous cleanup of highly viscous crude oil

Rapid cleanup of highly-viscous oil spills the sea is eagerly desired while still remains a great challenge. Hydrophobic and lipophilic adsorbents are regarded as ideal candidate for oil spill remediation. However, traditional adsorbents are not suitable for viscous crude oil, which would block the porous structure and lead to poor adsorption efficiency. In this work, a non-contact responsive superhydrophobic SiO₂ aerogel blankets (SAB) with excellent magnetic and solar heating effect for efficient removal of viscosity oils under harsh environments was developed, via assembled MXene and Fe₃O₄/polydimethylsiloxane layer-by-layer along the SAB skeleton (Fe₃O₄/MXene@SAB). The Fe₃O₄/MXene@SAB exhibited excellent compression tolerance (compression stress 70.69 kPa), superhydrophobic performance (water contact angle 166°), and corrosion resistance (weak acid/strong base). Due to high water repellency and stable porous structure, the Fe₃O₄/MXene@SAB could successfully separate oil-water mixture, while with remarkable separation flux (1.50-3.19 × 10⁴ L m^-2 h^-1), and separation efficiency (99.91-99.98 %). Furthermore, the responsive Fe₃O₄/MXene@SAB also showed outstanding magnetic-heating and solar-heating conversion efficiency, which could continuously separate high viscosity crude oil from seawater by pump even under relatively low magnetic fields and mild sun. The superhydrophobic blankets hold great promise for efficient treatment of heavy oil spills.

Application of aptamer-drug delivery system in the therapy of breast cancer

Despite significant treatment advances, breast cancer remains the leading cause of cancer death in women. From the current treatment situation, in addition to developing chemoresistant tumours, distant organ metastasis, and recurrences, patients with breast cancer often have a poor prognosis. Aptamers as "chemical antibodies" may be a way to resolve this dilemma. Aptamers are single-stranded, non-coding oligonucleotides (DNA or RNA), resulting their many advantages, including stability for long-term storage, simplicity of synthesis and function, and low immunogenicity, a high degree of specificity and antidote. Aptamers have gained popularity as a method for diagnosing and treating specific tumors in recent years. This article introduces the application of ten different aptamer delivery systems in the treatment and diagnosis of breast cancer, and systematically reviews their latest research progress in breast cancer treatment and diagnosis. It provides a new direction for the clinical treatment of breast cancer.

Synthesis and Characterization of SPIONs Encapsulating Polydopamine Nanoparticles and Their Test for Aqueous Cu2+ Ion Removal

The removal of pollutants, such as heavy metals, aromatic compounds, dyes, pesticides and pharmaceuticals, from water is still an open challenge. Many methods have been developed and exploited for the purification of water from contaminants, including photocatalytic degradation, biological treatment, adsorption and chemical precipitation. Absorption-based techniques are still considered among the most efficient and commonly used approaches thanks to their operational simplicity. In recent years, polydopamine-coated magnetic nanoparticles have emerged for the uptake of heavy metals in water treatment, since they combine specific affinity towards pollutants and magnetic separation capacity. In this context, this work focuses on the synthesis of polydopamine (PDA)-coated Super Paramagnetic Iron Oxide Nanoparticles (PDA@SPIONs) as adsorbents for Cu²⁺ ions, designed to serve as functional nanostructures for the removal of Cu²⁺ from water by applying a magnetic field. The synthetic parameters, including the amount of SPIONs and PDA, were thoroughly investigated to define their effects on the nanostructure features and properties. Subsequently, the ability of the magnetic nanostructures to bind metal ions was assessed on Cu²⁺-containing solutions. A systematic investigation of the prepared functional nanostructures was carried out by means of complementary spectroscopic, morphological and magnetic techniques. Inductively coupled plasma atomic emission spectroscopy (ICP-AES) measurements were performed in order to estimate the Cu²⁺ binding ability. The overall results indicate that these nanostructures hold great promise for future bioremediation applications.

Combinatorial Polydopamine-Liposome Nanoformulation as an Effective Anti-Breast Cancer Therapy

Introduction

Drug delivery systems (DDSs) based on liposomes are potential tools to minimize the side effects and substantially enhance the therapeutic efficacy of chemotherapy. However, it is challenging to achieve biosafe, accurate, and efficient cancer therapy of liposomes with single function or single mechanism. To solve this problem, we designed a multifunctional and multimechanism nanoplatform based on polydopamine (PDA)-coated liposomes for accurate and efficient combinatorial cancer therapy of chemotherapy and laser-induced PDT/PTT.

Methods

ICG and DOX were co-incorporated in polyethylene glycol modified liposomes, which were further coated with PDA by a facile two-step method to construct PDA-liposome nanoparticles (PDA@Lipo/DOX/ICG). The safety of nanocarriers was investigated on normal HEK-293 cells, and the cellular uptake, intracellular ROS production capacity, and combinatorial treatment effect of the nanoparticles were assessed on human breast cancer cells MDA-MB-231. In vivo biodistribution, thermal imaging, biosafety assessment, and combination therapy effects were estimated based on MDA-MB-231 subcutaneous tumor model.

Results

Compared with DOX·HCl and Lipo/DOX/ICG, PDA@Lipo/DOX/ICG showed higher toxicity on MDA-MB-231 cells. After endocytosis by target cells, PDA@Lipo/DOX/ICG produced a large amount of ROS for PDT by 808 nm laser irradiation, and the cell inhibition rate of combination therapy reached up to 80.4%. After the tail vein injection (DOX equivalent of 2.5 mg/kg) in mice bearing MDA-MB-231 tumors, PDA@Lipo/DOX/ICG significantly accumulated at the tumor site at 24 h post injection. After 808 nm laser irradiation (1.0 W/cm², 2 min) at this timepoint, PDA@Lipo/DOX/ICG efficiently suppressed the proliferation of MDA-MB-231 cell and even thoroughly ablated tumors. Negligible cardiotoxicity and no treatment-induced side effects were observed.

Conclusion

PDA@Lipo/DOX/ICG is a multifunctional nanoplatform based on PDA-coated liposomes for accurate and efficient combinatorial cancer therapy of chemotherapy and laser-induced PDT/PTT.

Application of a Dual-Probe Coloading Nanodetection System in the Process Monitoring and Efficacy Assessment of Photodynamic Therapy: An In Vitro Study

The oxygen-consuming property of photodynamic therapy (PDT) affects its effects and aggravates tumor hypoxia, thus upregulating the vascular endothelial growth factor (VEGF) to exacerbate tumor metastasis and lead to treatment failure. Therefore, it is necessary to monitor the dynamic changes in the factors related to PDT and tumor development trends in real time, thus helping to improve PDT efficiency. This study fabricated a fluorescent probe, TPE-2HPro, and a fluorescein-labeled aptamer probe, FAM-Aptamer_VEGF, to detect hydrogen peroxide (H₂O₂) and VEGF through the photoinduced electron-transfer effect and the specific affinity of the aptamer to VEGF, respectively. The two probes were loaded into the inner pores and absorbed on the surface of polydopamine coating-wrapped mesoporous silica nanoparticles (MSN@PDA) to construct the dual-probe-loaded system, MSN_TH@PDA_Apt, which was kept stable in fetal bovine serum (FBS) solution and achieved pH-responsive release behavior, thus helping to increase the accumulation of the two probes in tumor cells. The dichloroacetic acid-mediated in vitro antitumor tests showed that the changing trends of H₂O₂ and VEGF levels were consistent with the results of related mechanism studies and could be monitored by MSN_TH@PDA_Apt. The in vitro chlorin e6 (Ce6)-mediated PDT treatment demonstrated that when the illumination condition was 650 nm, 50 mW/cm² for 10 min, cells were more inclined to metastasis and invasion rather than death due to a substantial increase in VEGF expression at the low Ce6 concentrations. With the increase of the Ce6 concentration, the growth of the H₂O₂ level gradually exceeded that of VEGF, and the reactive oxygen species (ROS)-mediated cell death dominated when the Ce6 concentration was about 2 times its IC₅₀ values. Besides, hypoxia also affected the H₂O₂ and VEGF changes. These results demonstrated that MSN_TH@PDA_Apt could precisely monitor and assess the tumor development trends during PDT treatment, thus helping improve the treatment effect.

Cancer-Responsive Multifunctional Nanoplatform Based on Peptide Self-Assembly for Highly Efficient Combined Cancer Therapy by Alleviating Hypoxia and Improving the Immunosuppressive Microenvironment

Hypoxia, as a main feature of the tumor microenvironment, has greatly limited the efficacy of photodynamic therapy (PDT), as well as its clinical application. Here, a multifunctional composite nanoplatform, the peptide/Ce6/MnO₂ nanocomposite (RKCM), has been constructed to alleviate tumor hypoxia and increase the efficacy of PDT using rationally designed peptide fibrils to encapsulate chlorin e6 (Ce6) inside and to mineralize MnO₂ nanoparticles on the surface. As a result, RKCM significantly improved the PDT efficacy by increasing reactive oxygen species (ROS) generation, decreasing tumor cell viability, and inhibiting tumor growth and metastasis. Besides, decreased HIF-1α expression and increased immune-activated cell infiltration were also observed in RKCM/laser treatment xenograft. Mechanically, (1) Ce6 can induce singlet oxygen (¹O₂) generation under laser irradiation to give photodynamic therapy (PDT); (2) MnO₂ can react with H₂O₂ in situ to supply additional O₂ to alleviate tumor hypoxia; and (3) the released Mn²⁺ ions can induce a Fenton-like reaction to generate ^•OH for chemical dynamic therapy (CDT). Moreover, RKCM/laser treatment also presented with an abscopal effect to block the occurrence of lung metastasis by remolding the pre-metastasis immune microenvironment. With these several aspects working together, the peptide/Ce6/MnO₂ nanoplatform can achieve highly efficient tumor therapy. Such a strategy based on peptide self-assembly provides a promising way to rationally design a cancer-responsive multifunctional nanoplatform for highly efficient combined cancer therapy by alleviating hypoxia and improving the immune microenvironment.

Metal-organic frameworks: A promising option for the diagnosis and treatment of Alzheimer's disease

Beta-amyloid (Aβ) peptide is one of the main characteristic biomarkers of Alzheimer's disease (AD). Previous clinical investigations have proposed that unusual concentrations of this biomarker in cerebrospinal fluid, blood, and brain tissue are closely associated with the AD progression. Therefore, the critical point of early diagnosis, prevention, and treatment of AD is to monitor the levels of Aβ. In view of the potential of metal-organic frameworks (MOFs) for diagnosing and treating the AD, much attention has been focused in recent years. This review discusses the latest advances in the applications of MOFs for the early diagnosis of AD via fluorescence and electrochemiluminescence (ECL) detection of AD biomarkers, fluorescence detection of the main metal ions in the brain (Zn²⁺, Cu²⁺, Mn²⁺, Fe³⁺, and Al³⁺) in addition to magnetic resonance imaging (MRI) of the Aβ plaques. The current challenges and future strategies for translating the in vitro applications of MOFs into in vivo diagnosis of the AD are discussed.

Nanotechnology meets glioblastoma multiforme: Emerging therapeutic strategies

Glioblastoma multiforme (GBM) represents the most common and fatal form of primary invasive brain tumors as it affects a great number of patients each year and has a median overall survival of approximately 14.6 months after diagnosis. Despite intensive treatment, almost all patients with GBM experience recurrence, and their 5-year survival rate is approximately 5%. At present, the main clinical treatment strategy includes surgical resection, radiotherapy, and chemotherapy. However, tumor heterogeneity, blood-brain barrier, glioma stem cells, and DNA damage repair mechanisms hinder efficient GBM treatment. The emergence of nanometer-scale diagnostic and therapeutic approaches in cancer medicine due to the establishment of nanotechnology provides novel and promising tools that will allow us to overcome these difficulties. This review summarizes the application and recent progress in nanotechnology-based monotherapies (e.g., chemotherapy) and combination cancer treatment strategies (chemotherapy-based combined cancer therapy) for GBM and describes the synergistic enhancement between these combination therapies as well as the current standard therapy for brain cancer and its deficiencies. These combination therapies that can reduce individual drug-related toxicities and significantly enhance therapeutic efficiency have recently undergone rapid development. The mechanisms underlying these different nanotechnology-based therapies as well as the application of nanotechnology in GBM (e.g., in photodynamic therapy and chemodynamic therapy) have been systematically summarized here in an attempt to review recent developments and to identify promising directions for future research. This review provides novel and clinically significant insights and directions for the treatment of GBM, which is of great clinical importance. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease Diagnostic Tools > In Vivo Nanodiagnostics and Imaging.

Acid-triggered in vivo aggregation of Janus nanoparticles for enhanced imaging-guided photothermal therapy

Poor tumor delivery efficiency remains a significant challenge for the integrated nanoplatform for diagnosis and treatment. Nanotherapeutics capable of aggregation in response to the tumor microenvironment has received considerable attention because of its ability to enhance tumor delivery efficiency and accumulation. We prepared smart Au-Fe₃O₄ Janus nanoparticles (GIJ NPs) modified with mixed-charged ligands (3,4-dihydroxyhydrocinnamic acid [DHCA] and trimethylammonium dopamine [TMAD]). The obtained GIJ@DHCA-TMAD could be stable at the pH of the blood and normal tissues, but aggregated into larger particles in response to the tumor acidic microenvironment, leading to greatly enhanced accumulation in cancer cells. The hydrodynamic diameters of GIJ@DHCA-TMAD increased from 28.2 to 105.7 nm when the pH decreased from 7.4 to 5.5. Meanwhile, the T ₂ magnetic resonance imaging (MRI) contrast capability, photoacoustic imaging (PAI) performance, and photothermal conversion efficiency of GIJ@DHCA-TMAD were also enhanced with increasing diameter. Tumor-specific enhanced MRI and PAI can precisely locate tumor boundaries and can be used to perform preliminary photothermal tumor ablation therapy: the pH-sensitive GIJ@DHCA-TMAD can be used in dual-mode, tumor-specific imaging-guided photothermal therapy to better meet the multiple requirements for in vivo applications.

Graphene Oxide-Magnetic Nanoparticles Loaded Polystyrene-Polydopamine Electrospun Nanofibers Based Nanocomposites for Immunosensing Application of C-Reactive Protein

The large surface area/volume ratio and controllable surface conformation of electrospun nanofibers (ENFs) make them highly attractive in applications where a large surface area is desired, such as sensors and affinity membranes. In this study, nanocomposite-based ENFs were produced and immobilization of Anti-CRP was carried out for the non-invasive detection of C-reactive protein (CRP). Initially, the synthesis of graphene oxide (GO) was carried out and it was modified with magnetic nanoparticles (MNP, Fe₃O₄) and polydopamine (PDA). Catechol-containing and quinone-containing functional groups were created on the nanocomposite surface for the immobilization of Anti-CRP. Polystyrene (PS) solution was mixed with rGO-MNP-PDA nanocomposite and PS/rGO-MNP-PDA ENFs were produced with bead-free, smooth, and uniform. The surface of the screen-printed carbon electrode (SPCE) was covered with PS/rGO-MNP-PDA ENFs by using the electrospinning technique under the determined optimum conditions. Next, Anti-CRP immobilization was carried out and the biofunctional surface was created on the PS/rGO-MNP-PDA ENFs coated SPCE. Moreover, PS/rGO-PDA/Anti-CRP and PS/MNP-PDA/Anti-CRP immunosensors were also prepared and the effect of each component in the nanocomposite-based electrospun nanofiber (MNP, rGO) on the sensor response was investigated. The analytic performance of the developed PS/rGO-MNP-PDA/Anti-CRP, PS/rGO-PDA/Anti-CRP, and PS/MNP-PDA/Anti-CRP immunosensors were examined by performing electrochemical measurements in the presence of CRP. The linear detection range of PS/rGO-MNP-PDA/Anti-CRP immunosensor was found to be from 0.5 to 60 ng/mL and the limit of detection (LOD) was calculated as 0.33 ng/mL for CRP. The PS/rGO-MNP-PDA/Anti-CRP immunosensor also exhibited good repeatability with a low coefficient of variation.

Facile synthesis of phycocyanin/polydopamine hierarchical nanocomposites for synergizing PTT/PDT against cancer

The exceptional biocompatibility and biosafety of natural proteins have made them a popular choice for tumor therapy in recent years, but their therapeutic effectiveness is severely constrained by factors including physiological instability, insufficient delivery, limited accumulation in tumor cells, etc. Here, a novel Mn-doped phycocyanin (Pc)/polydopamine (PDA) hierarchical nanostructure (MnPc@P) with excellent optical absorption, photothermal conversion, and photodynamic performances, is first designed and fabricated by a simply one-pot reaction, which not only successfully encapsulates natural protein Pc with intact activity in the nanostructure of MnPc@P but also gives them better biocompatibility. Upon laser irradiation, PDA-mediated hyperthermia and Pc-induced ROS elevation in tumor cells have been demonstrated, leading to drastic tumor cell death via combined PTT/PDT effect, greater than single PTT or PDT. In general, the expert fusion of Pc and PDA into a single nanomedicine opens fascinating perspectives in the delivery of natural proteins and tumor therapy.

Polydopamine-Engineered Theranostic Nanoscouts Enabling Intracellular HSP90 mRNAs Fluorescence Detection for Imaging-Guided Chemo-Photothermal Therapy

The combination of photothermal therapy (PTT) and chemotherapy is considered a promising tumor treatment modality, nevertheless, cellular resistance induced by heat shock proteins (HSPs) overexpressed in tumor cells will restrict the therapeutic effect. Herein, a multifunctional nanobeacon DOX/HCuS@PDA-MB (D/CP-MB) with a scout function for HSP90 mRNA fluorescence detection and near-infrared (NIR) triggered drug release for sensitizing chemo-photothermal therapy, is proposed. In the theranostic nanobeacons, HSP90MBs not only enable fluorescence detection of intracellular HSP90 mRNAs, but also downregulate the expression of HSP90 to reduce cell resistance. With the assistance of NIR and guidance of fluorescence imaging, spatiotemporal doxorubicin release can be achieved by the trigger of the photothermal effect, allowing for combined chemotherapy and photothermal treatment. Furthermore, the dual photothermal effect of hollow mesoporous CuS (HCuS) and polydopamine will lead to a better photothermal effect. Moreover, compared with other control groups, D/CP-MB nanobeacons exhibit effective boost therapeutic efficacy by inducing significant suppression of tumor proliferation and enhancement of apoptosis both in vitro and in vivo. In summary, this work provides novel theranostic nanobeacons that integrate imaging and therapy in a single nanoparticle, this strategy of imaging-guided therapy can enable precise tumor treatment and effectively improve tumor treatment efficacy.

Simultaneous Enhancement of Magnetothermal and Photothermal Responses by Zn, Co Co-Doped Ferrite Nanoparticles

Reducing nanoparticle (NP) dosage for hyperthermia therapy has remained a great challenge. In this work, efficiencies of alternating current (AC) magnetic field and near-infrared (NIR) heating are simultaneously enhanced by Zn and Co co-doping of magnetite NPs. The optimum magnetic anisotropy for maximized loss power under each magnetic field is achieved by tuning the doping concentration. The specific loss power of Zn_0.3 Co_0.08 Fe_2.62 O₄ @SiO₂ NPs reaches 2428 W g^-1 under an AC field of 27 kA m^-1 at 430 kHz; 12 296 W g^-1 under NIR laser irradiation at 808 nm and 2.5 W cm^-2 ; and an unprecedented value of 14 724 W g^-1 under dual mode. These values far exceed what has been achieved previously in iron oxide NPs. Ex vivo experiments on sacrificial mice show that while the NP dosage is substantially reduced to that used for magnetic resonance imaging, the surface body temperature of the mice reaches 50 °C after exposure to both AC field and laser irradiation under field parameters and laser intensity below safety limits. This nanoplatform is thus promising for multi-modal local hyperthermia therapy.

Multifunctional microrobot with real-time visualization and magnetic resonance imaging for chemoembolization therapy of liver cancer

Microrobots that can be precisely guided to target lesions have been studied for in vivo medical applications. However, existing microrobots have challenges in vivo such as biocompatibility, biodegradability, actuation module, and intra- and postoperative imaging. This study reports microrobots visualized with real-time x-ray and magnetic resonance imaging (MRI) that can be magnetically guided to tumor feeding vessels for transcatheter liver chemoembolization in vivo. The microrobots, composed of a hydrogel-enveloped porous structure and magnetic nanoparticles, enable targeted delivery of therapeutic and imaging agents via magnetic guidance from the actuation module under real-time x-ray imaging. In addition, the microrobots can be tracked using MRI as postoperative imaging and then slowly degrade over time. The in vivo validation of microrobot system-mediated chemoembolization was demonstrated in a rat liver with a tumor model. The proposed microrobot provides an advanced medical robotic platform that can overcome the limitations of existing microrobots and current liver chemoembolization.

Perylene-Derived Hydrophilic Carbon Dots with Polychromatic Emissions as Superior Bioimaging and NIR-Responsive Photothermal Bactericidal Agent

Little progress has been achieved on the synthesis of hydrophilic carbon dots (CDs), derived from polycyclic aromatic hydrocarbons, as an excellent photothermal agent. In this study, a strategy was developed to synthesize highly photoluminescent greenish-yellow emissive CDs based on nitration followed by hydrothermal carbonization of the polycyclic aromatic hydrocarbon precursor, perylene. The perylene-derived CDs (PY-CDs) exhibited an excellent NIR-light (808 nm) harvesting property toward high photothermal conversion efficiency (PCE = ∼56.7%) and thus demonstrated remarkable NIR-light responsive photothermal bactericidal performance. Furthermore, these fluorescent PY-CD nanoprobes displayed excitation-dependent polychromatic emissions in the range of 538-600 nm, with the maximum emission at 538 nm. This enables intense multicolor biological imaging of cellular substances with long-term photostability, nontoxicity, and effective subcellular distribution. The bactericidal action of PY-CDs is likely due to the elevated reactive oxygen species amplification in cooperation with the hyperthermia effect. This study offers a potential substitute for multicolor imaging-guided metal-free carbon-based photothermal therapy.

Stem cell membrane-coated abiotic nanomaterials for biomedical applications

Nanoscale materials have been extensively employed for diagnostic and therapeutic purposes. However, the developed nanosystems still suffer from some limitations, namely the rapid elimination by the immune system, lack of targeting to specific cells, and insufficient biocompatibility. Therefore, novel strategies based upon a biomimetic approach have received attention to improving the pharmacokinetics and safety profile of nanosystems. One promising strategy is the application of a biomimetic coating consisting of cell membranes derived from different cell types onto nanoparticle cores. Stem cells have been investigated to develop targeted nanodevices owing to their excellent intrinsic tissue-specific homing features, protecting them from the immune system to reach the sites of inflammation. This targeting ability is conferred by a surface repertoire of stem cell-associated biomolecules. Such nanoscopical materials offer sustained circulation and boosted drug accumulation at target sites, augmenting therapeutic efficacy and safety. Additionally, the coating of nanoparticles with cell membranes acts as a camouflage mechanism to increase their circulation time. The current review explores the particular features of stem cell membrane coating as multifunctional biomimetic surface functionalization agents to camouflage nanoparticle cores. Biomedical applications of engineered stem cell membrane-coated nanoparticles, challenges in clinical translation, and their future prospects are addressed.