Increasing the Potential Interacting Area of Nanomedicine Enhances Its Homotypic Cancer Targeting Efficacy

Natural lignin nanoparticles target tumor by saturating the phagocytic capacity of Kupffer cells in the liver

Ligand-receptor recognition serves as the fundamental driving force for active targeting, yet it is still constrained by off-target effects. Herein, we demonstrate that circumventing or blocking the mononuclear phagocyte system (MPS) are both viable strategies to address off-target effects. Naturally derived lignin nanoparticles (LNPs) show great potential to block MPS due to its good stability, low toxicity, and degradability. We further demonstrate the impact of LNPs dosage on in vivo tumor targeting and antitumor efficacy. Our results show that a high dose of LNPs (300 mg/kg) leads to significant accumulation at the tumor site for a duration of 14 days after intravenous administration. In contrast, the low-dose counterparts (e.g., 50, 150 mg/kg) result in almost all LNPs accumulating in the liver. This discovery indicates that the liver is the primary site of LNP capture, leaving only the surplus LNPs the chance to reach the tumor. In addition, although cell membrane-engineered LNPs can rapidly penetrate tumors, they are still prone to capture by the liver during subsequent circulation in the bloodstream. Excitingly, comparable therapeutic efficacy is obtained for the above two strategies. Our findings may offer valuable insights into the targeted delivery of drugs for disease treatment.

Heating tumors with tumor cell-derived nanoparticles to enhance chemoimmunotherapy for colorectal cancer

Aim: To investigate the mechanism of doxorubicin (DOX)-induced immunogenic cell death (ICD) and to improve immunotherapy efficacy. Materials & methods: In this study, hybrid vesicles containing DOX (HV-DOX) were prepared by thin-film hydration with extrusion, and the formulated nanoparticles were characterized physically. Furthermore, in vitro experiments and animal models were used to investigate the efficacy and new mechanisms of chemotherapy combined with immunotherapy. Results: DOX improved tumor immunogenicity by alkalinizing lysosomes, inhibiting tumor cell autophagy and inducing ICD. HVs could activate dendritic cell maturation, synergistically enhancing chemotherapeutic immunity. Conclusion: The mechanism of DOX-induced ICD was explored, and antitumor immunity was synergistically activated by HV-DOX to improve chemotherapeutic drug loading and provide relevant antigenic information.

Cell-derived nanomaterials for biomedical applications

The ever-growing use of nature-derived materials creates exciting opportunities for novel development in various therapeutic biomedical applications. Living cells, serving as the foundation of nanoarchitectonics, exhibit remarkable capabilities that enable the development of bioinspired and biomimetic systems, which will be explored in this review. To understand the foundation of this development, we first revisited the anatomy of cells to explore the characteristics of the building blocks of life that is relevant. Interestingly, animal cells have amazing capabilities due to the inherent functionalities in each specialized cell type. Notably, the versatility of cell membranes allows red blood cells and neutrophils' membranes to cloak inorganic nanoparticles that would naturally be eliminated by the immune system. This underscores how cell membranes facilitate interactions with the surroundings through recognition, targeting, signalling, exchange, and cargo attachment. The functionality of cell membrane-coated nanoparticles can be tailored and improved by strategically engineering the membrane, selecting from a variety of cell membranes with known distinct inherent properties. On the other hand, plant cells exhibit remarkable capabilities for synthesizing various nanoparticles. They play a role in the synthesis of metal, carbon-based, and polymer nanoparticles, used for applications such as antimicrobials or antioxidants. One of the versatile components in plant cells is found in the photosynthetic system, particularly the thylakoid, and the pigment chlorophyll. While there are challenges in consistently synthesizing these remarkable nanoparticles derived from nature, this exploration begins to unveil the endless possibilities in nanoarchitectonics research.

Cancer Cell Membrane-Based Materials for Biomedical Applications

The nanodelivery system provides a novel direction for disease diagnosis and treatment; however, its delivery effectiveness is restricted by the short biological half-life and inadequate tumor targeting. The immune evasion properties and homologous targeting capabilities of natural cell membranes, particularly those of cancer cell membranes (CCM), have gained significant interest. The integration of CCM and nanoparticles has resulted in the emergence of CCM-based nanoplatforms (CCM-NPs), which have gained significant attention due to their unique properties. CCM-NPs not only prolong the blood circulation time of core nanoparticles, but also direct them for homologous tumor targeting. Herein, the history and development of CCM-NPs as well as how these platforms have been used for biomedical applications are discussed. The application of CCM-NPs for cancer therapy will be described in detail. Translational efforts are currently under way and further research to address key areas of need will ultimately be required to facilitate the successful clinical adoption of CCM-NPs.

One-Pot Synthesis of Tumor-Microenvironment Responsive Degradable Nanoflower-Medicine for Multimodal Cancer Therapy with Reinvigorating Antitumor Immunity

Multimodal cancer therapies show great promise in synergistically enhancing anticancer efficacy through different mechanisms. However, most current multimodal therapies either rely on complex assemblies of multiple functional nanomaterials and drug molecules or involve the use of nanomedicines with poor in vivo degradability/metabolizability, thus restricting their clinical translatability. Herein, a nanoflower-medicine using iron ions, thioguanine (TG), and tetracarboxylic porphyrin (TCPP) are synthesized as building blocks through a one-step hydrothermal method for combined chemo/chemodynamic/photodynamic cancer therapy. The resulting nanoflowers, consisting of low-density Fe2 O3 core and iron complex (Fe-TG and Fe-TCPP compounds) shell, exhibit high accumulation at the tumor site, desirable degradability in the tumor microenvironment (TME), robust suppression of tumor growth and metastasis, as well as effective reinvigoration of host antitumor immunity. Triggered by the low pH in tumor microenvironment, the nanoflowers gradually degrade after internalization, contributing to the effective drug release and initiation of high-efficiency catalytic reactions precisely in tumor sites. Moreover, iron ions can be eliminated from the body through renal clearance after fulfilling their mission. Strikingly, it is also found that the multimodal synergistic therapy effectively elicits the host antitumor immunity without inducing additional toxicity. This easy-manufactured and degradable multimodal therapeutic nanomedicine is promising for clinical precision oncology.

Cuproptosis-immunotherapy using PD-1 overexpressing T cell membrane-coated nanosheets efficiently treats tumor

The cuproptosis cell death pathway brings fresh opportunities for tumor therapy. However, efficient and targeted cuproptosis induction in tumors is still a challenge. Unfortunately, the well-known cuproptosis initiator, disulfiram and copper complex (DSF/Cu2+), also increases PD-L1 level in tumors, which may diminish the final therapeutic outcome. In this study, DSF/Cu2+-loading MXene nanosheets are coated with PD-1 overexpressing T cell membrane to generate CuX-P system. CuX-P could recognize and stick to PD-L1 on tumor cells like a patch, which promotes the endocytosis of both CuX-P and PD-L1 by tumor cells. Following internalization and release of DSF/Cu2+ in the cytoplasm, PD-L1 expression is upregulated. However, due to the presence of CuX-P in the tumor microenvironment, the then supplemented PD-L1 on tumor surface again binds CuX-P for internalization. This feedback loop keeps blocking and consuming the PD-L1 on tumor surface and promotes the enrichment of CuX-P in tumors to induce cuproptosis. After CuX-P treatment with laser irradiation, strong anti-tumor immune responses are stimulated in a mouse model with triple-negative breast cancer. Thus, this study develops a tumor-targeted biomimetic system that offers simultaneous cuproptosis killing, photothermal therapy (PTT) and immunotherapy in mice.

Black phosphorus quantum dots camouflaged with platelet-osteosarcoma hybrid membrane and doxorubicin for combined therapy of osteosarcoma

BACKGROUND

Osteosarcoma (OS) is the most prevalent primary malignant bone tumor. However, single-agent chemotherapy exhibits limited efficacy against OS and often encounters tumor resistance. Therefore, we designed and constructed an integrated treatment strategy of photothermal therapy (PTT) combined with chemotherapy and used a surface-encapsulated platelet-osteosarcoma hybrid membrane (OPM) that enhances circulation time and enables OS-specific targeting.

RESULTS

The OPM functions as a shell structure, encapsulating multiple drug-loaded nanocores (BPQDs-DOX) and controlling the release rate of doxorubicin (DOX). Moreover, near-infrared light irradiation accelerates the release of DOX, thereby extending circulation time and enabling photostimulation-responsive release. The OPM encapsulation system improves the stability of BPQDs, enhances their photothermal conversion efficiency, and augments PTT efficacy. In vitro and ex vivo experiments demonstrate that BPQDs-DOX@OPM effectively delivers drugs to tumor sites with prolonged circulation time and specific targeting, resulting in superior anti-tumor activity compared to single-agent chemotherapy. Furthermore, these experiments confirm the favorable biosafety profile of BPQDs-DOX@OPM.

CONCLUSIONS

Compared to single-agent chemotherapy, the combined therapy using BPQDs-DOX@OPM offers prolonged circulation time, targeted drug delivery, enhanced anti-tumor activity, and high biosafety, thereby introducing a novel approach for the clinical treatment of OS.

Chitosan-Based Smart Biomaterials for Biomedical Applications: Progress and Perspectives

Over the past decade, smart and functional biomaterials have escalated as one of the most rapidly emerging fields in the life sciences because the performance of biomaterials could be improved by careful consideration of their interaction and response with the living systems. Thus, chitosan could play a crucial role in this frontier field because it possesses many beneficial properties, especially in the biomedical field such as excellent biodegradability, hemostatic properties, antibacterial activity, antioxidant properties, biocompatibility, and low toxicity. Furthermore, chitosan is a smart and versatile biopolymer due to its polycationic nature with reactive functional groups that allow the polymer to form many interesting structures or to be modified in various ways to suit the targeted applications. In this review, we provide an up-to-date development of the versatile structures of chitosan-based smart biomaterials such as nanoparticles, hydrogels, nanofibers, and films, as well as their application in the biomedical field. This review also highlights several strategies to enhance biomaterial performance for fast growing fields in biomedical applications such as drug delivery systems, bone scaffolds, wound healing, and dentistry.

Recent Advances in Ferroelectric-Enhanced Low-Dimensional Optoelectronic Devices

Ferroelectric (FE) materials, including BiFeO₃ , P(VDF-TrFE), and CuInP₂ S₆ , are a type of dielectric material with a unique, spontaneous electric polarization that can be reversed by applying an external electric field. The combination of FE and low-dimensional materials produces synergies, sparking significant research interest in solar cells, photodetectors (PDs), nonvolatile memory, and so on. The fundamental aspects of FE materials, including the origin of FE polarization, extrinsic FE materials, and FE polarization quantification are first discussed. Next, the state-of-the-art of FE-based optoelectronic devices is focused. How FE materials affect the energy band of channel materials and how device structures influence PD performance are also summarized. Finally, the future directions of this rapidly growing field are discussed.

Metal-Organic Frameworks Applications in Synergistic Cancer Photo-Immunotherapy

Conventional cancer therapies, such as radiotherapy and chemotherapy, can have long-term side effects. Phototherapy has significant potential as a non-invasive alternative treatment with excellent selectivity. Nevertheless, its applicability is restricted by the availability of effective photosensitizers and photothermal agents, and its low efficacy when it comes to avoiding metastasis and tumor recurrence. Immunotherapy can promote systemic antitumoral immune responses, acting against metastasis and recurrence; however, it lacks the selectivity displayed by phototherapy, sometimes leading to adverse immune events. The use of metal-organic frameworks (MOFs) in the biomedical field has grown significantly in recent years. Due to their distinct properties, including their porous structure, large surface area, and inherent photo-responsive properties, MOFs can be particularly useful in the fields of cancer phototherapy and immunotherapy. MOF nanoplatforms have successfully demonstrated their ability to address several drawbacks associated with cancer phototherapy and immunotherapy, enabling an effective and low-side-effect combinatorial synergistical treatment for cancer. In the coming years, new advancements in MOFs, particularly regarding the development of highly stable multi-function MOF nanocomposites, may revolutionize the field of oncology.

Nanoscale coordination polymers enabling antioxidants inhibition for enhanced chemodynamic therapy

Reactive oxygen species (ROS) generation to induce cell death is an effective strategy for cancer therapy. In particular, chemodynamic therapy (CDT), using Fenton-type reactions to generate highly cytotoxic hydroxyl radical (•OH), is a promising treatment modality. However, the therapeutic efficacy of ROS-based cancer treatment is still limited by some critical challenges, such as overexpression of enzymatic and non-enzymatic antioxidants by tumor cells, as well as the low tumor targeting efficiency of therapeutic agents. To address those problems, biomimetic CuZn protoporphyrin IX nanoscale coordination polymers have been developed, which significantly amplify oxidative stress against tumors by simultaneously inhibiting enzymatic and non-enzymatic antioxidants and initiating the CDT. In this design, cancer cell membrane camouflaged nanoparticle exhibits an excellent homotypic targeting effect. After being endocytosed into tumor cells, the nanoparticles induce depletion of the main non-enzymatic antioxidant glutathione (GSH) by undergoing a redox reaction with GSH. Afterward, the redox reaction generated cuprous ion (Cu⁺) works as a CDT agent for •OH generation. Furthermore, the released Zn protoporphyrin IX strongly inhibits the activity of the typical enzymatic antioxidant heme oxygenase-1. This tetra-modal synergistic strategy endows the biomimetic nanoparticles with great capability for anticancer therapy, which has been demonstrated in both in vitro and in vivo studies.

Targeting treatment of bladder cancer using PTK7 aptamer-gemcitabine conjugate

BACKGROUND

Gemcitabine (GEM) is one of the first-line chemotherapies for bladder cancer (BC), but the GEMs cannot recognize cancer cells and have a low long-term response rate and high recurrence rate with side effects during the treatment of BC. Targeted transport of GEMs to mediate cytotoxicity to tumor and avoid the systemic side effects remains a challenge in the treatment of BC.

METHODS

Based on a firstly confirmed biomarker in BC-protein tyrosine kinase 7 (PTK7), which is overexpressed on the cell membrane surface in BC cells, a novel targeting system protein tyrosine kinase 7 aptamer-Gemcitabine conjugate (PTK7-GEMs) was designed and synthesized using a specific PTK7 aptamer and GEM through auto-synthesis method to deliver GEM against BC. In addition, the antitumor effects and safety evaluation of PTK7-GEMs was assessed with a series of in vitro and in vivo assays.

RESULTS

PTK7-GEMs can specifically bind and enter to BC cells dependent on the expression levels of PTK7 and via the macropinocytosis pathway, which induced cytotoxicity after GEM cleavage from PTK7-GEMs respond to the intracellular phosphatase. Moreover, PTK7-GEMs showed stronger anti-tumor efficacy and excellent biosafety in three types of tumor xenograft mice models.

CONCLUSION

These results demonstrated that PTK7-GEMs is a successful targeted aptamer-drug conjugates strategy (APDCs) to treat BC, which will provide new directions for the precision treatment of BC in the field of biomarker-oriented tumor targeted therapy.

Decrease in Tumor Interstitial Pressure for Enhanced Drug Intratumoral Delivery and Synergistic Tumor Therapy

Currently, one of the main reasons for the ineffectiveness of tumor treatment is that the abnormally high tumor interstitial pressure (TIP) hinders the delivery of drugs to the tumor center and promotes intratumoral cell survival and metastasis. Herein, we designed a "nanomotor" by in situ growth of Ag₂S nanoparticles on the surface of ultrathin WS₂ to fabricate Z-scheme photocatalytic drug AWS@M, which could rapidly enter tumors by splitting water in interstitial liquid to reduce TIP, along with O₂ generation. Moreover, the O₂ would be further converted to reactive oxygen species (ROS), accompanied by increased local temperature of tumors, and the combination of ROS with thermotherapy could eliminate the deep tumor cells. Therefore, the "nanomotor'' could effectively reduce the TIP levels of cervical cancer and pancreatic cancer (degradation rates of 40.2% and 36.1%, respectively) under 660 nm laser irradiation, further enhance intratumor drug delivery, and inhibit tumor growth (inhibition ratio 95.83% and 87.61%, respectively), and the related mechanism in vivo was explored. This work achieves efficiently photocatalytic water-splitting in tumor interstitial fluid to reduce TIP by the nanomotor, which addresses the bottleneck problem of blocking of intratumor drug delivery, and provides a general strategy for effectively inhibiting tumor growth.

Homotypic Targeted Photosensitive Nanointerferer for Tumor Cell Cycle Arrest to Boost Tumor Photoimmunotherapy

Recent advances in tumor immunotherapy mainly tend to remodel the immunosuppressive tumor microenvironment (TME) for immune enhancement. However, the complexity of TME makes it unlikely to achieve satisfactory therapeutic effects with any single intervention alone. Here, we focus on exposing intrinsic features of tumor cells to trigger direct pleiotropic antitumor immunity. We develop a photosensitive nanointerferer that is engineered with a nanoscale metal-organic framework decorated with tumor cell membranes for targeted delivery of a photosensitizer and small interfering RNA, which is used to knock down cyclin-dependent kinase 4 (Cdk4). Cdk4 blockade can arrest the cell cycle of tumor cells to facilitate antigen exposure and increase the expression level of programmed cell death protein ligand 1 (PD-L1). Under laser irradiation, photodynamic damage triggered by the nanointerferer induces the release of tumor antigens and recruitment of dendritic cells (DCs), thereby promoting the antitumor activity of CD8⁺ T cells in combination with anti-PD-L1 antibodies. Ultimately, these events markedly retard tumor progression in a mouse model of ectopic colon tumor with negligible adverse effects. This study provides an alternative treatment for effective antitumor immunity by exciting the intrinsic potential of tumor cells to initiate immune responses while reducing immune-related toxicities.

Structure-function relationships in polymeric multilayer capsules designed for cancer drug delivery

The targeted delivery of cancer drugs to tumor-specific molecular targets represents a major challenge in modern personalized cancer medicine. Engineering of micron and submicron polymeric multilayer capsules allows the obtaining of multifunctional theranostic systems serving as controllable stimulus-responsive tools with a high clinical potential to be used in cancer therapy and detection. The functionalities of such theranostic systems are determined by the design and structural properties of the capsules. This review (1) describes the current issues in designing cancer cell-targeting polymeric multilayer capsules, (2) analyzes the effects of the interactions of the capsules with the cellular and molecular constituents of biological fluids, and (3) presents the key structural parameters determining the effectiveness of capsule targeting. The influence of the morphological and physicochemical parameters and the origin of the structural components and surface ligands on the functional activity of polymeric multilayer capsules at the molecular, cellular, and whole-body levels are summarized. The basic structural and functional principles determining the future trends of theranostic capsule development are established and discussed.

Synthesis of Renal-Clearable Multicolor Fluorescent Silicon Nanodots for Tumor Imaging and In Vivo H2O2 Profiling

Fluorescent silicon nanodots have shown great prospects for bioimaging and biosensing applications. Although various fluorescent silicon-containing nanodots (SiNDs) have been developed, there are few reports about renal-clearable multicolor SiNDs. Herein, renal-clearable multicolor fluorescent SiNDs are synthesized by using silane molecules and organic dyes through a facile one-step hydrothermal method. The fluorescence of the resulting SiNDs can be tuned to blue (bSiNDs), green (gSiNDs), and red (rSiNDs) by simply changing the categories of silane reagents or dye molecules. The as-prepared SiNDs exhibit strong fluorescence with a quantum yield up to 72%, excellent photostability, and good biocompatibility with 12 h renal clearance rate as high as 86% ID. These properties enabled the SiNDs for tumor fluorescence imaging and H₂O₂ imaging in living cells and tissue through in situ reduction reaction-lighted fluorescence of the nanoprobe. Our results provide an invaluable methodology for the synthesis of renal-clearable multicolor SiNDs and their potential applications for fluorescence imaging and biomarker sensing. These SiNDs are also promising for various biological and biomedical applications.

Multifunctional Lipid Bilayer Nanocarriers for Cancer Immunotherapy in Heterogeneous Tumor Microenvironments, Combining Immunogenic Cell Death Stimuli with Immune Modulatory Drugs

In addition to the contribution of cancer cells, the solid tumor microenvironment (TME) has a critical role in determining tumor expansion, antitumor immunity, and the response to immunotherapy. Understanding the details of the complex interplay between cancer cells and components of the TME provides an unprecedented opportunity to explore combination therapy for intervening in the immune landscape to improve immunotherapy outcome. One approach is the introduction of multifunctional nanocarriers, capable of delivering drug combinations that provide immunogenic stimuli for improvement of tumor antigen presentation, contemporaneous with the delivery of coformulated drug or synthetic molecules that provide immune danger signals or interfere in immune-escape, immune-suppressive, and T-cell exclusion pathways. This forward-looking review will discuss the use of lipid-bilayer-encapsulated liposomes and mesoporous silica nanoparticles for combination immunotherapy of the heterogeneous immune landscapes in pancreatic ductal adenocarcinoma and triple-negative breast cancer. We describe how the combination of remote drug loading and lipid bilayer encapsulation is used for the synthesis of synergistic drug combinations that induce immunogenic cell death, interfere in the PD-1/PD-L1 axis, inhibit the indoleamine-pyrrole 2,3-dioxygenase (IDO-1) immune metabolic pathway, restore spatial access to activated T-cells to the cancer site, or reduce the impact of immunosuppressive stromal components. We show how an integration of current knowledge and future discovery can be used for a rational approach to nanoenabled cancer immunotherapy.

Tumor-targeted nano-delivery system of therapeutic RNA

The birth of RNAi technology has pioneered actionability at the molecular level. Compared to DNA, RNA is less stable and therefore requires more demanding delivery vehicles. With their flexible size, shape, structure, and accessible surface modification, non-viral vectors show great promise for application in RNA delivery. Different non-viral vectors have different ways of binding to RNA. Low immunotoxicity gives RNA significant advantages in tumor treatment. However, the delivery of RNA still has many limitations in vivo. This manuscript summarizes the size-targeting dependence of different organs, followed by a summary of nanovesicles currently in or undergoing clinical trials. It also reviews all RNA delivery systems involved in the current study, including natural, bionic, organic, and inorganic systems. It summarizes the advantages and disadvantages of different delivery methods, which will be helpful for future RNA vehicle design. It is hoped that this will be helpful for gene therapy of clinical tumors.

Bio-interactive nanoarchitectonics with two-dimensional materials and environments

Like the proposal of nanotechnology by Richard Feynman, the nanoarchitectonics concept was initially proposed by Masakazu Aono. The nanoarchitectonics strategy conceptually fuses nanotechnology with other research fields including organic chemistry, supramolecular chemistry, micro/nanofabrication, materials science, and bio-related sciences, and aims to produce functional materials from nanoscale components. In this review article, bio-interactive nanoarchitectonics and two-dimensional materials and environments are discussed as a selected topic. The account gives general examples of nanoarchitectonics of two-dimensional materials for energy storage, catalysis, and biomedical applications, followed by explanations of bio-related applications with two-dimensional materials such as two-dimensional biomimetic nanosheets, fullerene nanosheets, and two-dimensional assemblies of one-dimensional fullerene nanowhiskers (FNWs). The discussion on bio-interactive nanoarchitectonics in two-dimensional environments further extends to liquid-liquid interfaces such as fluorocarbon-medium interfaces and viscous liquid interfaces as new frontiers of two-dimensional environments for bio-related applications. Controlling differentiation of stem cells at fluidic liquid interfaces is also discussed. Finally, a conclusive section briefly summarizes features of bio-interactive nanoarchitectonics with two-dimensional materials and environments and discusses possible future perspectives.

Black Phosphorus nanoparticles for dual therapy of non-small cell lung cancer

Lung cancer remains one of the leading causes of death in humans. Gefitinib is an inhibitor of epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI) commonly used to suppress tumor growth. However, constantly use of gefitinib results in drug-resistance, reduced efficacy, and undesired side effects. To circumvent these drawbacks, targeted and photothermal therapies have emerged as effective strategies. Herein, we are first to adopt a black phosphorus nanoparticle-based novel delivering strategy by combining gefitinib and cancer cytomembrane to treat non-small cell lung cancer (NSCLC). In these gefitinib-containing nano-carrier, cyanine5 (Cy5) biotin-labeled black phosphorus was incorporated with cancer membrane and then consist of a nanomaterial (BPGM), which enabled to deliver gefitinib to the tumors effectively. The combination of BPGM showed reinforcing effects to suppress NSCLC cells and xenograft tumors without apparent adverse effects both in vitro and in vivo. BPGM facilitated the delivery of gefitinib to tumor tissue and extended its retention time within tumors. These studies thus suggest that black phosphorus may serve as novel delivery strategy for lung cancer.

Plasmonic Gold Nanoparticles Stain Hydrogels for the Portable and High-Throughput Monitoring of Mercury Ions

The hybrid of l-cysteine and agarose can reduce HAuCl₄ and support the rapid growth of plasmonic gold nanoparticles (Au NPs) in the hydrogel phase. The l-cysteine-doped agarose hydrogel (C-AGH) not only offers the substrate the capacity to reduce Au(III) ions but also stabilizes and precisely modulates the in situ grown Au NPs with high repeatability, easy operation, and anti-interference performance. Herein, before the incubation of HAuCl₄, the improved hydrogel is preincubated in the aqueous solution containing mercury ions, and the cysteine can specifically conjugate with mercury via the thiol groups. Subsequently, the responsive allochroic bands from dark blue to red can be identified in the solid hydrogel after the incubation of HAuCl₄, which is attributed to the formation of regulated Au-Hg nanoamalgams. As a proof-of-concept, toxic Hg²⁺ ions are exploited as targets for constructing novel sensing assays based on the improved C-AGH protocol. Based on naked-eye recognition, Hg²⁺ could be rapidly and simply measured. Additionally, the high-throughput and trace analysis with a low limit of detection (3.7 nM) is performed using a microplate reader. On the basis of the filtering technique and remodeling of hydrogels, C-AGH working as the filtering membrane can even achieve the integration of enrichment and measurement with enhanced sensitivity. Significantly, the strategy of using an allochroic hydrogel with the staining of Au NPs can promote the rapid and primary assessment of water quality in environmental analysis.

Oxygenic Enrichment in Hybrid Ruthenium Sulfide Nanoclusters for an Optimized Photothermal Effect

Transition-metal dichalcogenide (TMD)-based nanomaterials have been extensively explored for the photonic therapy. To the best of our knowledge, near-infrared (NIR) light is a requirement for the photothermal therapy (PTT) to achieve the feature of deep-tissue penetration, whereas no obvious absorption peaks existing in the NIR region for existing TMD nanomaterials limit their therapeutic efficacy. As one category of TMD nanomaterials, ruthenium sulfide-based nanomaterials have been less exploited in biomedical applications including tumor therapy so far. Here, we develop a facile biomineralization-assisted bottom-up strategy to synthesize oxygenic hybrid ruthenium sulfide nanoclusters (RuS_x NCs) by regulating the oxygen amounts and sulfur defects for the optimized PTT. By regulating the increasing initial molar ratios of Ru to S, RuS_x NCs with small sizes were endowed with increasing oxygen contents and sulfur defects, leading to the photothermal conversion efficiency (PCE) increasing from 32.8 to 41.9%, which were higher than that of most small-sized inorganic photothermal nanoagents. In contrast to commercial indocyanine green, these RuS_x NCs exhibited higher photostability under NIR laser irradiation. The high PCE and superior photostability allowed RuS_x NCs to effectively and completely ablate cancer cells. Thus, the proposed defect engineering strategy endows RuS_x NCs with an excellent photothermal effect for the PTT of tumors of living mice, which also proves the potential of further exploring the properties of RuS_x NCs for future biomedical applications.

Recent advances in cell membrane camouflage-based biosensing application

Cell membrane, a semi-permeable membrane composed of phospholipid bilayers, is a natural barrier to prevent extracellular substances from freely entering the cell. Cell membrane with selective permeability and fluidity ensures the relative stability of the intracellular environment and enables various biochemical reactions to smoothly operate in an orderly manner. Inspired by the natural composition and transport process, various cell membranes and synthetic bionic films as the mimics of cell membranes have emerged as appealing camouflage materials for biosensing applications. The membranes are devoted to surface modification and substance delivery, and realize the detection or in situ analysis of multiple biomarkers, such as glucose, nucleic acids, virus, and circulating tumor cells. In this review, we summarize the recent advances in cell membrane camouflage-based biosensing applications, mainly focusing on the use of the membranes extracted from natural cells (e.g., blood cells and cancer cells) as well as biomimetic membranes. Materials and surfaces camouflaged with cell membranes are shown to have superior stability and biocompatibility as well as intrinsic properties of original cells, which greatly facilitate their use in biosensing. In specific, camouflage with blood cell membranes bestows low immunogenicity and prolonged blood circulation time, camouflage with cancer cell membranes provides homologous targeting ability, and camouflage with biomimetic membranes endows considerable plasticity for functionalization. Further research is expected to focus on the deeper understanding of cell-specific properties of membranes and the exploration of hybrid membranes, which might provide new development opportunities for cell membrane camouflage-based biosensing application.

Near infrared photothermal conversion materials: mechanism, preparation, and photothermal cancer therapy applications

Photothermal therapy (PTT) has been widely applied in cancer therapy as a result of its non-invasive, localized treatment and good therapeutic effect. In general, the final therapeutic effect of PTT mainly depends on the photothermal materials, which can be further considered to be determined by the photothermal conversion efficiency, biocompatibility, and photothermal stability of photothermal materials. In this review, photothermal materials including inorganic materials, organic materials, and organic-inorganic composite materials in recent years have been summarized in terms of the mechanism, preparation, and cancer therapy applications. In the end, the perspectives and obstacles in their further development are overviewed.

Nanomediator-Effector Cascade Systems for Amplified Protein Kinase Activity Imaging and Phosphorylation-Induced Drug Release In Vivo

Protein kinases constitute a rich pool of biomarkers and therapeutic targets of tremendous diseases including cancer. However, sensing kinase activity in vivo while implementing treatments according to kinase hyperactivation remains challenging. Herein, we present a nanomediator-effector cascade system that can in situ magnify the subtle events of kinase-catalyzed phosphorylation via DNA amplification machinery to achieve kinase activity imaging and kinase-responsive drug release in vivo. In this cascade, the phosphorylation-mediated disassembly of DNA/peptide complex on the nanomediators initiated the detachment of fluorescent hairpin DNAs from the nanoeffectors via hybridization chain reaction (HCR), leading to fluorescence recovery and therapeutic cargo release. We demonstrated that this nanosystem simultaneously enabled trace protein kinase A (PKA) activity imaging and on-demand drug delivery for inhibition of tumor cell growth both in vitro and in vivo, affording a kinase-specific sense-and-treat paradigm for cancer theranostics.

Thermostability, Tunability, and Tenacity of RNA as Rubbery Anionic Polymeric Materials in Nanotechnology and Nanomedicine-Specific Cancer Targeting with Undetectable Toxicity

RNA nanotechnology is the bottom-up self-assembly of nanometer-scale architectures, resembling LEGOs, composed mainly of RNA. The ideal building material should be (1) versatile and controllable in shape and stoichiometry, (2) spontaneously self-assemble, and (3) thermodynamically, chemically, and enzymatically stable with a long shelf life. RNA building blocks exhibit each of the above. RNA is a polynucleic acid, making it a polymer, and its negative-charge prevents nonspecific binding to negatively charged cell membranes. The thermostability makes it suitable for logic gates, resistive memory, sensor set-ups, and NEM devices. RNA can be designed and manipulated with a level of simplicity of DNA while displaying versatile structure and enzyme activity of proteins. RNA can fold into single-stranded loops or bulges to serve as mounting dovetails for intermolecular or domain interactions without external linking dowels. RNA nanoparticles display rubber- and amoeba-like properties and are stretchable and shrinkable through multiple repeats, leading to enhanced tumor targeting and fast renal excretion to reduce toxicities. It was predicted in 2014 that RNA would be the third milestone in pharmaceutical drug development. The recent approval of several RNA drugs and COVID-19 mRNA vaccines by FDA suggests that this milestone is being realized. Here, we review the unique properties of RNA nanotechnology, summarize its recent advancements, describe its distinct attributes inside or outside the body and discuss potential applications in nanotechnology, medicine, and material science.

Recent progress in targeted delivery vectors based on biomimetic nanoparticles

Over the past decades, great interest has been given to biomimetic nanoparticles (BNPs) since the rise of targeted drug delivery systems and biomimetic nanotechnology. Biological vectors including cell membranes, extracellular vesicles (EVs), and viruses are considered promising candidates for targeted delivery owing to their biocompatibility and biodegradability. BNPs, the integration of biological vectors and functional agents, are anticipated to load cargos or camouflage synthetic nanoparticles to achieve targeted delivery. Despite their excellent intrinsic properties, natural vectors are deliberately modified to endow multiple functions such as good permeability, improved loading capability, and high specificity. Through structural modification and transformation of the vectors, they are pervasively utilized as more effective vehicles that can deliver contrast agents, chemotherapy drugs, nucleic acids, and genes to target sites for refractory disease therapy. This review summarizes recent advances in targeted delivery vectors based on cell membranes, EVs, and viruses, highlighting the potential applications of BNPs in the fields of biomedical imaging and therapy industry, as well as discussing the possibility of clinical translation and exploitation trend of these BNPs.

Natural discoidal lipoproteins with tiny modification for tumor extracellular dissociation in antitumor chemoimmunotherapy

Appealing cancer immunotherapy requires synchronous presentation of tumor antigens and immunoadjuvant. Herein, a "one-step" modification strategy is proposed to tinily remould endogenous discoidal high density lipoprotein (dHDL) for tumor-homing and site-specific chemoimmunotherapy. For molecular targeting therapy, lipophilic immunoadjuvant CpG oligodeoxynucleotides is conjugated to facilitate HDL-surface anchoring; and GC nucleotides provide enough reservoir for completion of doxorubicin (Dox) "sandwich". After administration, the tiny size (~30 nm) of disc nanodrug can maneuver deeply into tumors for receptor binding and in situ structural collapse. The intracellular concentrated CpG-Dox induce potent immunogenic cell death from burst Dox liberation at acidic pH. In turn, the released antigens and CpG motifs are simultaneously recognized by dendritic cells for antigen presentation and antitumor T cell responses. Combination chemoimmunotherapy with discoidal nanodrugs performed highest tumor weight inhibitory of 93.2% and extend the median survival time at a safe level. Collectively, this study suggests that the minimalist revolution of natural dHDL particulates may provide a biomimicry nanoplatform for site-specific amplified chemoimmunotherapy.

Recent Progress of Alkyl Radicals Generation-Based Agents for Biomedical Applications

Photodynamic therapy (PDT) is extensively explored for anticancer and antibacterial applications. It typically relies on oxygen-dependent generation of reactive oxygen species (ROS) to realize its killing effect. This type of therapy modality shows compromised therapeutic results for treating hypoxic tumors or bacteria-infected wounds. Recently, alkyl radicals attracted much attention as they can be generated from some azo-based initiators only under mild heat stimulus without oxygen participation. Many nanocarriers or hydrogel systems have been developed to load and deliver these radical initiators to lesion sites for theranostics. These systems show good anticancer or antimicrobial effect in hypoxic environment and some of them possess specific imaging abilities providing precise guidance for treatment. This review summarizes the developed materials that aim at treating hypoxic cancer and bacteria-infected wound by using this kind of oxygen-irrelevant alkyl radicals. Based on the carrier components, these agents are divided into three groups: inorganic, organic, as well as inorganic and organic hybrid carrier-based therapeutic systems. The construction of these agents and their specific advantages in biomedical field are highlighted. Finally, the existing problems and future promising development directions are discussed.

Development of Polymeric Nanoparticles for Blood-Brain Barrier Transfer-Strategies and Challenges

Neurological disorders such as Alzheimer's disease, stroke, and brain cancers are difficult to treat with current drugs as their delivery efficacy to the brain is severely hampered by the presence of the blood-brain barrier (BBB). Drug delivery systems have been extensively explored in recent decades aiming to circumvent this barrier. In particular, polymeric nanoparticles have shown enormous potentials owing to their unique properties, such as high tunability, ease of synthesis, and control over drug release profile. However, careful analysis of their performance in effective drug transport across the BBB should be performed using clinically relevant testing models. In this review, polymeric nanoparticle systems for drug delivery to the central nervous system are discussed with an emphasis on the effects of particle size, shape, and surface modifications on BBB penetration. Moreover, the authors critically analyze the current in vitro and in vivo models used to evaluate BBB penetration efficacy, including the latest developments in the BBB-on-a-chip models. Finally, the challenges and future perspectives for the development of polymeric nanoparticles to combat neurological disorders are discussed.

Immunogenic Hybrid Nanovesicles of Liposomes and Tumor-Derived Nanovesicles for Cancer Immunochemotherapy

Exploring a rational delivery system of integrating chemotherapy with immunotherapy to broaden benefits of cancer immunochemotherapy is still under challenge. Herein, we developed doxorubicin (DOX)-loaded biomimetic hybrid nanovesicles (DOX@LINV) via fusing artificial liposomes (LIPs) with tumor-derived nanovesicles (TNVs) for combinational immunochemotherapy. DOX@LINV with a homologous targeting ability could deliver DOX to tumor tissue and elicit an effective immunogenic cell death response to improve the immunogenicity of a tumor. Meanwhile, the preserved tumor antigens and endogenous danger signals in DOX@LINV activated dendritic cells and induced a subsequent antigen-specific T cell immune response. DOX@LINV displayed a specific antitumor effect on murine melanoma, Lewis lung cancer, and 4T1 breast cancer based on the infiltration of effector immune cells and improvement of the immunosuppressive tumor microenvironment. Furthermore, the combination of DOX@LINV with immune checkpoint inhibitor amplified antitumor efficacy with 33.3% of the mice being tumor-free. Therefore, the hybrid LINV is a promising drug delivery platform with a boosted antitumor immune response for effective immunochemotherapy.

Controllable synthesis and formation mechanism study of homoleptic alkynyl-protected Au nanoclusters: recent advances, grand challenges, and great opportunities

In the past decade, atomically precise coinage metal nanoclusters have been a subject of major interest in nanoscience and nanotechnology because of their determined compositions and well-defined molecular structures, which are beneficial for establishing structure-property relationships. Recently ligand engineering has been extended to alkynyl molecules. Homoleptic alkynyl-protected Au nanoclusters (Au NCs) have emerged as a hotspot of research interest, mainly due to their unique optical properties, molecular configuration, and catalytic functionalities, and more importantly, they are used as a counterpart object for fundamental study to compare with the well-established thiolate Au NCs. In this review, we first summarize the recently reported various controllable synthetic strategies for atomically precise homoleptic-alkynyl-protected Au NCs, with particular emphasis on the ligand exchange method, direct reduction of the precursor, one-pot synthesis, and the synchronous nucleation and passivation strategy. After that, we switch our focus to the formation mechanism and structure evolution process of homoleptic alkynyl-protected Au NCs, where Au144(PA)60 and Au36(PA)24 (PA = phenylacetylide) are given as examples, along with the prediction of the possible formation mechanism of some other cluster molecules. In the end of this review, the outlook and perspective of this rapidly developing field including grand challenges and great opportunities are discussed. This review can stimulate more research efforts towards developing new synthetic strategies to enrich the limited examples and unravel the formation/growth mechanism of homoleptic alkynyl-protected Au NCs.

Cell-Membrane-Display Nanotechnology

Advances in material science have set the stage for nanoparticle-based research with potent applications for the diagnosis, bioimaging, and precise treatment of diseases. Despite the wide range of biomaterials developed, the rational design of biomaterials with predictable bioactivity and safety remains a critical challenge. In recent years, the field of cell-membrane-based therapeutics has emerged as a promising platform for addressing unmet medical needs. The utilization of natural cell membranes endows biomaterials with a remarkable ability to serve as biointerfaces that interact with the host environment. To improve the function and efficacy of cell-membrane-based therapeutics, a series of novel strategies is developed as cell-membrane-display nanotechnology, which utilizes various methods to selectively display therapeutic molecules of cell membranes on nanoparticles. Although cell-membrane-display nanotechnology remains in the early phases, considerable work is currently being conducted in the field. This review discusses details of innovative strategies for displaying cell-membrane molecules, including the following: 1) displaying molecules of cell membranes on biomaterials, 2) pretreating cell membranes to induce increased expression of inherent molecules of cell membranes and enhance their function, and 3) inserting additional functional molecules on cell membranes. For each area, the theoretical basis, application scenarios, and potential development are highlighted.

Increased photodynamic therapy sensitization in tumors using a nitric oxide-based nanoplatform with ATP-production blocking capability

Photodynamic therapy (PDT) efficacy in cancer cells is affected by sub-physiological hypoxia caused by dysregulated and “chaotic” tumor microvasculature. However, current traditional O₂-replenishing strategies are undergoing their own intrinsic deficiencies. In addition, resistance mechanisms activated during PDT also lead the present situation far from satisfactory.

Methods: We propose a nitric oxide (NO)-based theranostic nanoplatform by using biocompatible poly-lactic-co-glycolic acid nanoparticles (PLGA NPs) as carriers, in which the outer polymeric layer embeds chlorin e6 (Ce6) and incorporates L-Arginine (L-Arg). This nanoplatform (L-Arg@Ce6@P NPs) can reduce hyperactive O₂ metabolism of tumor cells by NO-mediated mitochondrial respiration inhibition, which should raise endogenous O₂ tension to counteract hypoxia. Furthermore, NO can also hinder oxidative phosphorylation (OXPHOS) which should cause intracellular adenosine triphosphate (ATP) depletion, inhibiting tumor cells proliferation and turning cells more sensitive to PDT.

Results: When the L-Arg@Ce6@P NPs accumulate in solid tumors by the enhanced permeability and retention (EPR) effect, locally released L-Arg is oxidized by the abundant H₂O₂ to produce NO. In vitro experiments suggest that NO can retard hypoactive O₂ metabolism and save intracellular O₂ for enhancing PDT efficacy under NIR light irradiation. Also, lower intracellular ATP hinders proliferation of DNA, improving PDT sensitization. PDT phototherapeutic efficacy increased by combining these two complementary strategies in vitro/in vivo.

Conclusion: We show that this NO-based nanoplatform can be potentially used to alleviate hypoxia and sensitize tumor cells to amplify the efficacy of phototherapy guided by photoacoustic (PA) imaging.

Aggregation-induced responses (AIR) of 2D-derived layered nanostructures enable emerging colorimetric and fluorescence sensors

Layered nanostructures (LNs), including two-dimensional nanosheets, nanoflakes, and planar nanodots, show large surface-to-volume ratios, unique optical properties, and desired interfacial activities. LNs are highly promising as alternative probes and platforms due to numerous merits, e.g. signal amplification, improved recognition ability, and anti-interference capacity, for emerging sensing applications. Significantly, when stimuli-responsive aggregation occurs, the modified LNs show engineered morphologies, attractive optical absorption and fluorescence characteristics, which are remarkably programmable. On the basis of the altered aggregation behaviours of LNs, as well as their modulated physical and chemical characteristics, a series of novel sensing assays exhibiting enhanced sensitivity, simple operation, multiple functions, and improved anti-interference capacity are reported, contributing to both point-of-care testing and high-throughput measurements. Herein, the aggregation-induced response sensing strategies of LNs are comprehensively summarized with the classification of materials and variation of aggregated routes aiming at understanding dimension-dependent features, expanding nanoscale biosensor applications, and addressing key issues in disease diagnosis and environmental analysis.

Molecular recognition at the air-water interface: nanoarchitectonic design and physicochemical understanding

Although molecular recognition at the air-water interface has been researched for over 30 years, investigations on its fundamental aspects are still active research targets in current science. In this perspective article, developments and future possibilities of molecular recognition at the air-water interface from pioneering research efforts to current examples are overviewed especially from the physico-chemical viewpoints. Significant enhancements of binding constants for molecular recognition are actually observed at the air-water interface although molecular interactions such as hydrogen bonding are usually suppressed in aqueous media. Recent advanced analytical strategies for direct characterization of interfacial molecules also confirmed the promoted formation of hydrogen bonding at the air-water interfaces. Traditional quantum chemical approaches indicate that modulation of electronic distributions through effects from low-dielectric phases would be the origin of enhanced molecular interactions at the air-water interface. Further theoretical considerations suggest that unusual potential changes for enhanced molecular interactions are available only within a limited range from the interface. These results would be related with molecular recognition in biomolecular systems that is similarly supported by promoted molecular interactions in interfacial environments such as cell membranes, surfaces of protein interiors, and macromolecular interfaces.

Overcoming bacterial physical defenses with molecule-like ultrasmall antimicrobial gold nanoclusters

The size of metal nanoparticles (NPs) is crucial in their biomedical applications. Although abundant studies on the size effects of metal NPs in the range of 2-100 nm have been conducted, the exploration of the ultrasmall metal nanoclusters (NCs) of ~1 nm in size with unique features is quite limited. We synthesize three different sized gold (Au) NCs of different Au atom numbers and two bigger sized Au NPs protected by the same ligand to study the size influence on antimicrobial efficacy. The ultrasmall Au NCs can easily traverse the cell wall pores to be internalized inside bacteria, inducing reactive oxygen species generation to oxidize bacterial membrane and disturb bacterial metabolism. This explains why the Au NCs are antimicrobial while the Au NPs are non-antimicrobial, suggesting the key role of size in antimicrobial ability. Moreover, in contrast to the widely known size-dependent antimicrobial properties, the Au NCs of different atom numbers demonstrate molecule-like instead of size-dependent antimicrobial behavior with comparable effectiveness, indicating the unique molecule-like feature of ultrasmall Au NCs. Overcoming the bacterial defenses at the wall with ultrasmall Au NCs changes what was previously believed to harmless to the bacteria instead to a highly potent agent against the bacteria.

Retooling Cancer Nanotherapeutics' Entry into Tumors to Alleviate Tumoral Hypoxia

Anti-hypoxia cancer nanomedicine (AHCN) holds exciting potential in improving oxygen-dependent therapeutic efficiencies of malignant tumors. However, most studies regarding AHCN focus on optimizing structure and function of nanomaterials with presupposed successful entry into tumor cells. From such a traditional perspective, the main barrier that AHCN needs to overcome is mainly the tumor cell membrane. However, such an oversimplified perspective would neglect that real tumors have many biological, physiological, physical, and chemical defenses preventing the current state-of-the-art AHCNs from even reaching the targeted tumor cells. Fortunately, in recent years, some studies are beginning to intentionally focus on overcoming physiological barriers to alleviate hypoxia. In this Review, the limitations behind the traditional AHCN delivery mindset are addressed and the key barriers that need to be surmounted before delivery to cancer cells and some good ways to improve cell membrane attachment, internalization, and intracellular retention are summarized. It is aimed to contribute to Review literature on this emerging topic through refreshing perspectives based on this work and what is also learnt from others. This Review would therefore assist AHCNs researchers to have a quick overview of the essential information and glean thought-provoking ideas to advance this sub-field in cancer nanomedicine.