In situ activation of platelets with checkpoint inhibitors for post-surgical cancer immunotherapy

Platelets in cancer and immunotherapy: functional dynamics and therapeutic opportunities

Platelets play a critical role in tumor immunity, particularly in promoting cancer progression. Numerous studies suggest that platelets could serve as a novel target for cancer immunotherapy, however, no comprehensive reviews have yet summarized and discussed this potential. Our review provides an in-depth discussion of the roles and mechanisms of platelets within both the immunosuppressive tumor microenvironment and the anti-tumor immune microenvironment. Additionally, we summarize the key therapeutic targets and approaches for clinical translation. This work offers essential insights for reprogramming platelets to shift their function from tumor promotion to tumor suppression, providing a foundation for the development of novel immunotherapeutic strategies and related research.

Advanced biomaterials for the targeted delivery of immune checkpoint inhibitors to solid tumors

Immune checkpoint inhibitors (ICIs) have revolutionized the way cancer is treated by engaging the patient's own immune system to attack cancer. ICIs can also achieve favorable outcomes in patients whose cancers are unresponsive or resistant to first-line therapies. Despite these exciting prospects, ICIs are ineffective in many patients and cause immune-related adverse events (irAEs) in up to 89 % of patients. Therefore, there is a clear clinical need to reduce irAEs while maintaining or improving the therapeutic efficacy of ICIs. The local administration of ICIs through intratumoral injection or peritumoral administration has been shown to increase the potency of these therapeutics while reducing irAEs and extending survival in preclinical models. However, the rapid systemic distribution of intratumorally delivered drugs (hours) prevents this strategy from achieving even better efficacy and reduced toxicity; this is particularly problematic for ICIs due to their long biological (weeks), consequently acting at non-target sites for weeks before being cleared by the body. Engineered biomaterials have the potential to enhance local administration by improving permeation and retention, employing antibody-mediated targeting, leveraging tumor microenvironment sense-and-respond systems, or taking advantage of cell trafficking. This paper reviews the cutting-edge delivery strategies shown to improve the safety and efficacy of drugs targeting PD-1, PD-L1, and CTLA-4 and identifies the most promising strategies for clinical translation.

In vitro and in vivo metabolic tagging and modulation of platelets

Platelets play a critical role in hemostasis at sites of injury and are capable of interacting with various types of cells in the bloodstream. The promise of utilizing platelets for diagnostic and therapeutic applications has motivated the development of facile strategies to functionalize platelets. However, platelets with a small size, lack of nucleus and efficient protein machinery, and low tolerance to chemicals and transfection agents have posed significant challenges for chemical or genetic engineering. Here, for the first time, we report successful metabolic glycan labeling of platelets to introduce chemical tags (e.g., azido groups) onto the membrane of platelets. We demonstrate that azido-sugars can metabolically label platelets in a concentration dependent manner, with cell-surface azido groups detectable at as early as 4 hours. The cell-surface azido groups enable the conjugation of various macromolecular cargos including proteins and polymers onto platelets via efficient click chemistry. Small-molecule drugs such as doxorubicin can also be conjugated onto azido-labeled platelets and become subsequently released to kill surrounding cancer cells, demonstrating the feasibility of utilizing platelets as a drug delivery vehicle. We further show that azido-sugars, upon intraperitoneal injection, can metabolically label platelets with azido groups in vivo, which persist for up to 4 days in mice (nearly the life-span of murine platelets). This in vitro and in vivo platelet labeling and targeting technology opens a new avenue to platelet-based diagnostics and therapeutics.

Engineering colloidal systems for cell manipulation, delivery, and tracking

Men-made colloidal systems are widely presented across various aspects of biomedical science. There is a strong demand for engineering colloids to tailor their functions and properties to meet the requirements of biological and medical tasks. These requirements are not only related to size, shape, capacity to carry bioactive compounds as drug delivery systems, and the ability to navigate via chemical and physical targeting. Today, the more challenging aspects of colloid design are how the colloidal particles interact with biological cells, undergo internalization by cells, how they reside in the cell interior, and whether we can explore cells with colloids, intervene with biochemical processes, and alter cell functionality. Cell tracking, exploitation of cells as natural transporters of internalized colloidal carriers loaded with drugs, and exploring physical methods as external triggers of cell functions are ongoing topics in the research agenda. In this review, we summarize recent advances in these areas, focusing on how colloidal particles interact and are taken up by mesenchymal stem cells, dendritic cells, neurons, macrophages, neutrophils and lymphocytes, red blood cells, and platelets. The engineering of colloidal vesicles with cell membrane fragments and exosomes facilitates their application. The perspectives of different approaches in colloid design, their limitations, and obstacles on the biological side are discussed.

Long-acting bioengineered platelets with internal doxorubicin loaded and external quercetin liposomes anchored for post-surgical tumor therapy

Due to its natural tumor targeting ability, platelet-based drug delivery platform shows the great potential for tumor targeted treatment. However, both limited in vitro storage stability and rapid in vivo clearance rate severely restrict its clinical application. Here, utilizing the spatial structure of platelets precisely, chemotherapy drug doxorubicin (Dox) and liposomes-containing quercetin (Que) are loaded inside and anchored outside platelets, respectively, for establishing the engineered platelet platform (PDQLs). Dox plays the important role in inhibiting tumor growth, while Que mainly inhibits platelet apoptosis through activating serine/threonine protein kinase. PDQLs show the strong ability to resist external stimulation and physical damage. After being stored at room temperature for 4 days, more than 70 % of the platelets remain active. Given the natural wound tropism and tumor targeting abilities, the tumor accumulation of PDQLs is 1.02-fold higher than that of the solution. Base on the stealth characteristics of platelets and the continuous action of Que, PDQLs exhibit 10.63-fold increase area under the curve of solution. PDQLs can balance the anti-tumor recurrence and metastasis efficacy after surgery and safety. Our findings open a promising perspective and new sights for the development of bioengineered platelet platform in clinical application.

Implantable Immunostimulant Microneedle Patch for Post-Surgical Prevention of Cancer Recurrence and Distant Tumor Inhibition

Cancer recurrence after surgical resection remains a grand challenge in achieving long-term eradication. Here, we develop a biocompatible and implantable immunostimulant microneedle patch designed to suppress local tumor recurrence after surgery. The patch, fabricated using methacrylate-modified hyaluronic acid, incorporates 2'3'-cGAMP, a STING agonist, and IL-2, a cytokine approved for clinical cancer immunotherapy that expands T cells. The patch enables controlled release of cGAMP to induce dendritic cell maturation, antitumor macrophage polarization (M1 macrophage), and T cell priming and activation. Simultaneously, localized IL-2 activates CD8+ T cells and recruits immune cells to the tumor microenvironment. When combined with an anti-CTLA-4 antibody, an immune checkpoint blockade, the hybrid microneedle patch significantly reduces Treg cells at the surgery sites, enhancing immune responses and effectively inhibiting the progression of distant tumors in both prophylactic and therapeutic models. Compared with traditional postsurgical chemotherapy and radiotherapy, this patch-mediated immunotherapy demonstrates superior efficacy in mitigating tumor relapse while offering higher biocompatibility. Our findings suggest that this immunotherapeutic patch has potential as a translational tool to prevent cancer recurrence in patients with resectable tumors.

Tumor Microenvironment Triggered In Situ Coagulation of Supramolecularly Engineered Platelets for Precise Tumor Embolization

Although embolization therapy has demonstrated success in impeding tumor growth, concerns persist regarding potential tumor recurrence and inadvertent embolization of non-target tissues. In this study, drawing inspiration from the natural targeting and coagulation process of platelets in injured blood vessels, platelets are engineered by integrating acid-sensitive, morphology-transformable nanoparticles onto their surface through supramolecular conjugation (PLT-NP). The nanoparticles are constructed through the self-assembly of a β-amyloid derived peptide (FFVLK) terminally functionalized with Fmoc, hexahistidine (His6), and a polyethylene glycol (PEG)-functionalized cyclodextrin (CD). The supramolecularly engineered platelets actively accumulate in the tumor tissue upon inducing a tumor blood vessel injury through tumor resection. In response to the local acidic microenvironment, the nanoparticles undergo a morphological transformation into nanofibers via spontaneous assembly of FFLVK into fibril structures through hydrogen bonding and β-sheet interactions, to artificially enhance the coagulation and aggregation of platelets, causing occlusion of tumor blood vessels. The supramolecularly engineered platelets efficiently embolize tumor blood vessels in a specific manner, effectively suppressing tumor growth, metastasis, and recurrence, thus offering a promising paradigm for combating cancer.

Cancer Biology and the Perioperative Period: Opportunities for Disease Evolution and Challenges for Perioperative Care

Efforts to deconvolve the complex interactions of cancer cells with other components of the tumor micro- and macro-environment have exposed a common tendency for cancers to subvert systems physiology and exploit endogenous programs involved in homeostatic control of metabolism, immunity, regeneration, and repair. Many such programs are engaged in the healing response to surgery which, together with other abrupt biochemical changes in the perioperative period, provide an opportunity for the macroevolution of residual disease. This review relates contemporary perspectives of cancer as a systemic disease with the overlapping biology of host responses to surgery and events within the perioperative period. With a particular focus on examples of cancer cell plasticity and changes within the host, we explore how perioperative inflammation and acute metabolic, neuroendocrine, and immune dyshomeostasis might contribute to cancer evolution within this contextually short, yet crucially influential timeframe, and highlight potential therapeutic opportunities within to further optimize surgical cancer care and its long-term oncological outcomes.

Pyridinium Rotor Strategy toward a Robust Photothermal Agent for STING Activation and Multimodal Image-Guided Immunotherapy for Triple-Negative Breast Cancer

The immunosuppressive tumor microenvironment in triple-negative breast cancer could hinder the response to thorough immunotherapy and diminish the antitumor efficacy. Although the STING pathway emerges as a promising target to remedy defects, uncertain drug delivery might lead to off-target inflammatory reactions. Here, we manifest a novel phototheranostic agent with an aggregation-induced emission property that guided the pharmacological activation of a STING agonist for photothermal immunotherapy to create an immunologically "hot" tumor. A pyridinium rotor strategy is proposed to develop a positively charged TBTP-Bz, which is stably coincorporated with a STING agonist MSA-2 into thermal-responsive exosome-liposome hybrid nanoparticles for tumor-targeting delivery. TBTP-Bz exhibits aggregation-enhanced NIR-II emission and a photoacoustic signal, accomplishing real-time tumor tracking. Its photothermal stimulation induces immunogenic cancer cell death and promotes the precise release of MSA-2, thus boosting STING activation and STING-mediated type I interferon production. Significantly, single-dose photoimmunotherapy effectively suppresses abscopal tumor growth and provokes an immune memory effect to inhibit postsurgical recurrent and rechallenged tumors. This demonstrates promising clinical potential for poorly immunogenic breast cancer.

Microwave-Responsive Engineered Platelet Microneedle Patch for Deep Tumor Penetration and Precision Therapy

Controllable and precise delivery of therapeutic agents is critical for effective tumor therapy. However, tumor targeting and the deep penetration of drugs remain among the most challenging issues in achieving controlled delivery. Herein, a novel engineered platelet microneedle patch with a microwave-responsive magnetic biometal-organic framework is proposed to facilitate the combination of the engineered platelet and microwave hyperthermia, enhancing deep drug penetration into tumors and enabling precision therapy. The prepared magnetic biometal-organic framework as nanomedicine exhibits excellent microwave thermal effects. The engineered platelets could be activated in the tumor microenvironment to release PMPs and nanomedicines combined with microwave hyperthermia for enhancing both cell uptake and deep drug penetration into tumors. The developed separable microneedle patch system allows the microneedle tip to be quickly detached from the backing layer and retained within the target tissue for repeated local cancer hyperthermia treatments. By integration of engineered platelets into the microneedle patch, the transdermal deep delivery of drugs could be effectively enhanced for local microwave thermochemotherapy of tumors. This work represents the first attempt to graft microwave-responsive inorganic nanomedicines onto platelets as cell drugs, offering a novel strategy for precise drug delivery activated by microwave thermal therapy.

Platelet backpacking nanoparticles based on bacterial outer membrane vesicles enhanced photothermal-immune anti-tumor therapy

Bacterial outer membrane vesicles (OMVs), produced by Gram-negative bacteria, retain the immunostimulatory capacity of parental bacteria. OMVs have been recognized as potent natural immune adjuvants and drug delivery vehicles. Photothermal therapy that triggers immunogenic cell death further stimulates the immune system by releasing damage-associated molecular patterns. This therapeutic effect can be synergized with OMVs to achieve enhanced anti-tumor outcomes. We also observed that tumors can recruit platelets. Leveraging the phenomenon, we have innovatively employed platelets as "couriers" to boost the tumor-targeting delivery efficiency of both OMVs and photothermal agents. In detail, based on OMVs, we meticulously engineered nanoparticles (IR780-SLN@O-P) with platelet-binding capacity. These "courier" platelets carry "cargo" IR780-SLN@O-P NPs to tumor sites via P-selectin, ensuring targeted delivery. Under laser irradiation, the photothermal agents generate significant photothermal effects, which combined with the immune-stimulating properties of OMVs, creating a robust anti-tumor immune response. For "cold" tumors such as triple-negative breast cancer (TNBC), our IR780-SLN@O-P NPs not only prolonged the survival of mice bearing 4T1 orthotopic tumors, but also significantly suppressed tumor growth. Moreover, they facilitated dendritic cell maturation and the infiltration of CD8+ T cells to ameliorate the immunosuppressive tumor environment. Our research aims to highlight the unique advantages of OMVs and explore the potential of the tumor-targeting strategy that synergizes photothermal therapy with immunotherapy. We hope that our findings can offer insights into TNBC clinical treatments.

Bioengineered therapeutic systems for improving antitumor immunity

Immunotherapy, a monumental advancement in antitumor therapy, still yields limited clinical benefits owing to its unguaranteed efficacy and safety. Therapeutic systems derived from cellular, bacterial and viral sources possess inherent properties that are conducive to antitumor immunotherapy. However, crude biomimetic systems have restricted functionality and may produce undesired toxicity. With advances in biotechnology, various toolkits are available to add or subtract certain properties of living organisms to create flexible therapeutic platforms. This review elaborates on the creation of bioengineered systems, via gene editing, synthetic biology and surface engineering, to enhance immunotherapy. The modifying strategies of the systems are discussed, including equipment for navigation and recognition systems to improve therapeutic precision, the introduction of controllable components to control the duration and intensity of treatment, the addition of immunomodulatory components to amplify immune activation, and the removal of toxicity factors to ensure biosafety. Finally, we summarize the advantages of bioengineered immunotherapeutic systems and possible directions for their clinical translation.

Engineered platelets as targeted protein degraders and application to breast cancer models

Clinical application of chimeric molecules for targeted protein degradation has been limited by unfavorable drug-like properties and biosafety concerns arising from nonspecific biodistribution after systemic administration. Here we develop a method to engineer platelets for degradation of either intracellular or extracellular proteins of interest (POIs) in vivo by covalently labeling heat shock protein 90 (HSP90) in platelets with a POI ligand. The degrader platelets (DePLTs) target wound areas and undergo activation. Depending on the tethered POI ligand and transport mechanism of the prelabeled HSP90, activated DePLTs can mediate targeted protein degradation in the target cell through the ubiquitin-proteasome machinery or the lysosome. HSP90 packaged into platelet-derived microparticles uses the ubiquitin-proteasome system to degrade intracellular POIs, whereas released free HSP90 redirects extracellular POIs to lysosomal degradation. In postsurgical breast cancer mouse models, DePLTs engineered with corresponding POI ligands effectively degrade intracellular bromodomain-containing protein 4 or extracellular programmed cell death ligand 1, thereby suppressing cancer recurrence or metastasis.

Advances in drug delivery systems utilizing blood cells and their membrane-derived microvesicles

The advancement of drug delivery systems (DDSs) in recent decades has demonstrated significant potential in enhancing the efficacy of pharmacological agents. Despite the approval of certain DDSs for clinical use, challenges such as rapid clearance from circulation, toxic accumulation in the body, and ineffective targeted delivery persist as obstacles to successful clinical application. Blood cell-based DDSs have emerged as a popular strategy for drug administration, offering enhanced biocompatibility, stability, and prolonged circulation. These DDSs are well-suited for systemic drug delivery and have played a crucial role in formulating optimal drug combinations for treating a variety of diseases in both preclinical studies and clinical trials. This review focuses on recent advancements and applications of DDSs utilizing blood cells and their membrane-derived microvesicles. It addresses the current therapeutic applications of blood cell-based DDSs at the organ and tissue levels, highlighting their successful deployment at the cellular level. Furthermore, it explores the mechanisms of cellular uptake of drug delivery vectors at the subcellular level. Additionally, the review discusses the opportunities and challenges associated with these DDSs.

Liquid biopsy: paving a new avenue for cancer research

The current constraints associated with cancer diagnosis and molecular profiling, which rely on invasive tissue biopsies or clinical imaging, have spurred the emergence of the liquid biopsy field. Liquid biopsy involves the extraction of circulating tumor cells (CTCs), circulating free or circulating tumor DNA (cfDNA or ctDNA), circulating cell-free RNA (cfRNA), extracellular vesicles (EVs), and tumor-educated platelets (TEPs) from bodily fluid samples. Subsequently, these components undergo molecular characterization to identify biomarkers that are critical for early cancer detection, prognosis, therapeutic assessment, and post-treatment monitoring. These innovative biosources exhibit characteristics analogous to those of the primary tumor from which they originate or interact. This review comprehensively explores the diverse technologies and methodologies employed for processing these biosources, along with their principal clinical applications.

Protecting Against Postsurgery Oral Cancer Recurrence with an Implantable Hydrogel Vaccine for In Situ Photoimmunotherapy

Oral squamous cell carcinoma (OSCC) often recurs aggressively and metastasizes despite surgery and adjuvant therapy, driven by postoperative residual cancer cells near the primary tumor site. An implantable in situ vaccine hydrogel was designed to target residual OSCC cells post-tumor removal. This hydrogel serves as a reservoir for the sustained localized release of δ-aminolevulinic acid (δ-ALA), enhancing protoporphyrin IX-mediated photodynamic therapy (PDT), and a polydopamine-hyaluronic acid composite for photothermal therapy (PTT). Additionally, immune adjuvants, including anti-CD47 antibodies (aCD47) and CaCO3 nanoparticles, are directly released into the resected tumor bed. This approach induces apoptosis of residual OSCC cells through sequential near-infrared irradiation, promoting calcium interference therapy (CIT). The hydrogel further stimulates immunogenic cell death (ICD), facilitating the polarization of tumor-associated macrophages from the M2 to the M1 phenotype. This facilitates phagocytosis, dendritic cell activation, robust antigen presentation, and cytotoxic T lymphocyte-mediated cytotoxicity. In murine OSCC models, the in situ vaccine effectively prevents local recurrence, inhibits orthotopic OSCC growth and pulmonary metastases, and provides long-term protective immunity against tumor rechalle nge. These findings support postoperative in situ vaccination with a biocompatible hydrogel implant as a promising strategy to minimize residual tumor burden and reduce recurrence risk after OSCC resection.

STING-activating dendritic cell-targeted nanovaccines that evoke potent antigen cross-presentation for cancer immunotherapy

Recently, nanovaccine-based immunotherapy has been robustly investigated due to its potential in governing the immune response and generating long-term protective immunity. However, the presentation of a tumor peptide-major histocompatibility complex to T lymphocytes is still a challenge that needs to be addressed for eliciting potent antitumor immunity. Type 1 conventional dendritic cell (cDC1) subset is of particular interest due to its pivotal contribution in the cross-presentation of exogenous antigens to CD8+ T cells. Here, the DC-derived nanovaccine (denoted as Si9GM) selectively targets cDC1s with marginal loss of premature antigen release for effective stimulator of interferon genes (STING)-mediated antigen cross-presentation. Bone marrow dendritic cell (BMDC)-derived membranes, conjugated to cDC1-specific antibody (αCLEC9A) and binding to tumor peptide (OVA257-264), are coated onto dendrimer-like polyethylenimine (PEI)-grafted silica nanoparticles. Distinct molecular weight-cargos (αCLEC9A-OVA257-264 conjugates and 2'3'-cGAMP STING agonists) are loaded in hierarchical center-radial pores that enables lysosome escape for potent antigen-cross presentation and activates interferon type I, respectively. Impressively, Si9GM vaccination leads to the upregulation of cytotoxic T cells, a reduction in tumor regulatory T cells (Tregs), M1/M2 macrophage polarization, and immune response that synergizes with αPD-1 immune checkpoint blockade. This nanovaccine fulfills a dual role for both direct T cell activation as an artificial antigen-presenting cell and DC subset maturation, indicating its utility in clinical therapy and precision medicine.

In vivo gene editing of T-cells in lymph nodes for enhanced cancer immunotherapy

Immune checkpoint blockade (ICB) therapy, while promising for cancer treatment, faces challenges like unexpected side effects and limited objective responses. Here, we develop an in vivo gene-editing strategy for improving ICB cancer therapy in a lastingly effective manner. The approach uses a conductive hydrogel-based electroporation system to enable nucleofection of programmed cell death protein 1 (PD1) targeted CRISPR-Cas9 DNAs into T-cells directly within the lymph nodes, and subsequently produces PD1-deficient T-cells to combat tumor growth, metastasis and recurrence in different melanoma models in mice. Following in vivo gene editing, animals show enhanced cellular and humoral immune responses along with multi-fold increases of effector T-cells infiltration to the solid tumors, preventing tumor recurrence and prolonging their survival. These findings provide a proof-of-concept for direct in vivo T-cell engineering via localized gene-editing for enhanced cancer immunotherapy, and also unlock the possibilities of using this method to treat more complex human diseases.

Cell-mediated nanoparticle delivery systems: towards precision nanomedicine

Cell-mediated nanoparticle delivery systems (CMNDDs) utilize cells as carriers to deliver the drug-loaded nanoparticles. Unlike the traditional nanoparticle drug delivery approaches, CMNDDs take the advantages of cell characteristics, such as the homing capabilities of stem cells, inflammatory chemotaxis of neutrophils, prolonged blood circulation of red blood cells, and internalization of macrophages. Subsequently, CMNDDs can easily prolong the blood circulation, cross biological barriers, such as the blood-brain barrier and the bone marrow-blood barrier, and rapidly arrive at the diseased areas. Such advantageous properties make CMNDDs promising delivery candidates for precision targeting. In this review, we summarize the recent advances in CMNDDs fabrication and biomedical applications. Specifically, ligand-receptor interactions, non-covalent interactions, covalent interactions, and internalization are commonly applied in constructing CMNDDs in vitro. By hitchhiking cells, such as macrophages, red blood cells, monocytes, neutrophils, and platelets, nanoparticles can be internalized or attached to cells to construct CMNDDs in vivo. Then we highlight the recent application of CMNDDs in treating different diseases, such as cancer, central nervous system disorders, lung diseases, and cardiovascular diseases, with a brief discussion about challenges and future perspectives in the end.

Cell-drug conjugates

By combining living cells with therapeutics, cell-drug conjugates can potentiate the functions of both components, particularly for applications in drug delivery and therapy. The conjugates can be designed to persist in the bloodstream, undergo chemotaxis, evade surveillance by the immune system, proliferate, or maintain or transform their cellular phenotypes. In this Review, we discuss strategies for the design of cell-drug conjugates with specific functions, the techniques for their preparation, and their applications in the treatment of cancers, autoimmune diseases and other pathologies. We also discuss the translational challenges and opportunities of this class of drug-delivery systems and therapeutics.

Engineering supramolecular peptide nanofibers for in vivo platelet-hitchhiking beyond ligand-receptor recognition

Ex vivo or in vivo cell-hitchhiking has emerged as a potential means for efficient drug delivery and various disease therapies. However, many challenges remain, such as the complicated engineering process and dependence on ligand-receptor interaction. Here, we present a simple in vivo platelet-hitchhiking strategy based on self-assembling peptides without ligand modification. The engineered peptide nanofibers can hitchhike ultrafast (<5 s) and efficiently on both resting and activated platelets in a receptor-independent and species-independent manner. Mechanistic studies showed that unique secondary structure of nanofibers, which lead to surface exposure of hydrophobic and hydrogen bond-forming groups, might primarily contribute to the selective and efficient platelet-hitchhiking behavior. After intravenous injection, these peptide nanofibers hitchhiked in situ on circulating platelets and achieved almost 20-fold lung accumulation. Our study provides not only a different paradigm of in vivo platelet-hitchhiking beyond ligand-receptor recognition but also a potential strategy for lung-targeted drug delivery and pulmonary disease therapy.

Bioresponsive Immunotherapeutic Materials

The human immune system is an interaction network of biological processes, and its dysfunction is closely associated with a wide array of diseases, such as cancer, infectious diseases, tissue damage, and autoimmune diseases. Manipulation of the immune response network in a desired and controlled fashion has been regarded as a promising strategy for maximizing immunotherapeutic efficacy and minimizing side effects. Integration of "smart" bioresponsive materials with immunoactive agents including small molecules, biomacromolecules, and cells can achieve on-demand release of agents at targeted sites to reduce overdose-related toxicity and alleviate off-target effects. This review highlights the design principles of bioresponsive immunotherapeutic materials and discusses the critical roles of controlled release of immunoactive agents from bioresponsive materials in recruiting, housing, and manipulating immune cells for evoking desired immune responses. Challenges and future directions from the perspective of clinical translation are also discussed.

Engineered Platelet for In Situ Natural Killer Cell Activation to Inhibit Tumor Recurrence

Natural killer (NK) cells offer profound advantages against tumor recurrence due to their unique immunological behavior. NK cell therapies associated with the antibody-dependent cell-mediated cytotoxicity (ADCC) effect have made remarkable progress while being limited by insufficient antibody binding and the exhausted state of NK cells in the postsurgical immunosuppressive microenvironment. Leveraging the adherence of PLT to tumor cells, we developed an exogenously implanted platelet (PLT)-based NK cell-driven system (PLT-IgG-IL15) to improve the identifiability of residual tumors with IgG antibody labeling for NK cells catching and engaging, which consequently restored the ADCC effect and promoted the recovery of their killing function. Furthermore, interleukin-15 (IL-15) participated in the augmentation of NK cell function. Collectively, PLT-IgG-IL15 served as an NK cell tumor cell engager as well as an NK cell charger, achieving a <40% recurrence rate in mouse tumor models.

Platelet-Drug Conjugates Engineered via One-step Fusion Approach for Metastatic and Postoperative Cancer Treatment

The exploration of cell-based drug delivery systems for cancer therapy has gained growing attention. Approaches to engineering therapeutic cells with multidrug loading in an effective, safe, and precise manner while preserving their inherent biological properties remain of great interest. Here, we report a strategy to simultaneously load multiple drugs in platelets in a one-step fusion process. We demonstrate doxorubicin (DOX)-encapsulated liposomes conjugated with interleukin-15 (IL-15) could fuse with platelets to achieve both cytoplasmic drug loading and surface cytokine modification with a loading efficiency of over 70 % within minutes. Due to their inherent targeting ability to metastatic cancers and postoperative bleeding sites, the engineered platelets demonstrated a synergistic therapeutic effect to suppress lung metastasis and postoperative recurrence in mouse B16F10 melanoma tumor models.

From bench to bedside: Platelet biomimetic nanoparticles as a promising carriers for personalized drug delivery

In recent decades, there has been a burgeoning interest in cell membrane coating strategies as innovative approach for targeted delivery systems in biomedical applications. Platelet membrane-coated nanoparticles (PNPs), in particular, are gaining interest as a new route for targeted therapy due to their advantages over conventional drug therapies. Their stepwise approach blends the capabilities of the natural platelet membrane (PM) with the adaptable nature of manufactured nanomaterials, resulting in a synergistic combination that enhances drug delivery and enables the development of innovative therapeutics. In this context, we present an overview of the latest advancements in designing PNPs with various structures tailored for precise drug delivery. Initially, we describe the types, preparation methods, delivery mechanisms, and specific advantages of PNPs. Next, we focus on three critical applications of PNPs in diseases: vascular disease therapy, cancer treatment, and management of infectious diseases. This review presents our knowledge of PNPs, summarizes their advancements in targeted therapies and discusses the promising potential for clinical translation of PNPs.

Optimized Bionic Drug-Delivery-Inducing Immunogenic Cell Death and cGAS-STING Pathway Activation for Enhanced Photodynamic-Chemotherapy-Driven Immunotherapy in Prostate Cancer

Prostate cancer presents as a challenging disease, as it is often characterized as an immunologically "cold" tumor, leading to suboptimal outcomes with current immunotherapeutic approaches in clinical settings. Photodynamic therapy (PDT) harnesses reactive oxygen species generated by photosensitizers (PSs) to disrupt the intracellular redox equilibrium. This process induces DNA damage in both the mitochondria and nucleus, activating the process of immunogenic cell death (ICD) and the cGAS-STING pathway. Ultimately, this cascade of events leads to the initiation of antitumor immune responses. Nevertheless, existing PSs face challenges, including suboptimal tumor targeting, aggregation-induced quenching, and insufficient oxygen levels in the tumor regions. To this end, a versatile bionic nanoplatform has been designed for the simultaneous delivery of the aggregation-induced emission PS TPAQ-Py-PF6 and paclitaxel (PTX). The cell membrane camouflage of the nanoplatform leads to its remarkable abilities in tumor targeting and cellular internalization. Upon laser irradiation, the utilization of TPAQ-Py-PF6 in conjunction with PTX showcases a notable and enhanced synergistic antitumor impact. Additionally, the nanoplatform has the capability of initiating the cGAS-STING pathway, leading to the generation of cytokines. The presence of damage-associated molecular patterns induced by ICD collaborates with these aforementioned cytokines lead to the recruitment and facilitation of dendritic cell maturation. Consequently, this elicits a systemic immune response against tumors. In summary, this promising strategy highlights the use of a multifunctional biomimetic nanoplatform, combining chemotherapy, PDT, and immunotherapy to enhance the effectiveness of antitumor treatment.

A bioinspired doxorubicin-carried albumin Nanocage against aggressive Cancer via systemic targeting of tumor and lymph node metastasis

Cancer metastasis and recurrence are obstacles to successful treatment of aggressive cancer. To address this challenge, chemotherapy is indispensable as an essential part of comprehensive cancer treatment, particularly for subsequent therapy after surgical resection. However, small-molecule drugs for chemotherapy always cause inadequate efficacy and severe side effects against cancer metastasis and recurrence caused by lymph node metastases. Here, we developed doxorubicin-carried albumin nanocages (Dox-AlbCages) with appropriate particle sizes and pH/enzyme-responsive drug release for tumor and lymph node dual-targeted therapy by exploiting the inborn transport properties of serum albumin. Inspired by the protein-templated biomineralization and remote loading of doxorubicin into liposomes, we demonstrated the controlled synthesis of Dox-AlbCages via the aggregation or crystallization of doxorubicin and ammonium sulfate within albumin nanocages using a biomineralization strategy. Dox-AlbCages allowed efficient encapsulation of Dox in the core protected by the albumin corona shell, exhibiting favorable properties for enhanced tumor and lymph node accumulation and preferable cellular uptake for tumor-specific chemotherapy. Intriguingly, Dox-AlbCages effectively inhibited tumor growth and metastasis in orthotopic 4T1 breast tumors and prevented postsurgical tumor recurrence and lung metastasis. At the same time, Dox-AlbCages had fewer side effects than free Dox. This nanoplatform provides a facile strategy for designing tumor- and lymph node-targeted nanomedicines for suppressing cancer metastasis and recurrence.

Enhancing in situ cancer vaccines using delivery technologies

In situ cancer vaccination refers to any approach that exploits tumour antigens available at a tumour site to induce tumour-specific adaptive immune responses. These approaches hold great promise for the treatment of many solid tumours, with numerous candidate drugs under preclinical or clinical evaluation and several products already approved. However, there are challenges in the development of effective in situ cancer vaccines. For example, inadequate release of tumour antigens from tumour cells limits antigen uptake by immune cells; insufficient antigen processing by antigen-presenting cells restricts the generation of antigen-specific T cell responses; and the suppressive immune microenvironment of the tumour leads to exhaustion and death of effector cells. Rationally designed delivery technologies such as lipid nanoparticles, hydrogels, scaffolds and polymeric nanoparticles are uniquely suited to overcome these challenges through the targeted delivery of therapeutics to tumour cells, immune cells or the extracellular matrix. Here, we discuss delivery technologies that have the potential to reduce various clinical barriers for in situ cancer vaccines. We also provide our perspective on this emerging field that lies at the interface of cancer vaccine biology and delivery technologies.

Bioorthogonal targeted cell membrane vesicles/cell-sheet composites reduce postoperative tumor recurrence and scar formation of melanoma

While surgical resection is the predominant clinical strategy in the treatment of melanoma, postoperative recurrence and undetectable metastasis are both pernicious drawbacks to this otherwise highly successful approach. Furthermore, the deep cavities result from tumor excision can leave long lasting wounds which are slow to heal and often leave visible scars. These unmet needs are addressed in the present work through the use of a multidimensional strategy, and also promotes wound healing and scar reduction. In the first phase, cell membrane-derived nanovesicles (NVs) are engineered to show PD-1 and dibenzocyclooctyne (DBCO). These are capable of reactivating T cells by blocking the PD-1/PD-L1 pathway. In the second phase, azido (N3) labeled mesenchymal stem cells (MSCs) are cultured into cell sheets using tissue engineering, then apply directly to surgical wounds to enhance tissue repair. Owing to the complementary association between DBCO and N3 groups, PD-1 NVs were accumulated at the site of excision. This strategy can inhibit postoperative tumor recurrence and metastasis, whilst also promoting wound healing and reducing scar formation. The results of this study set a precedent for a new and innovative multidimensional therapeutic strategy in the postoperative treatment of melanoma.

Grooved Microneedle Patch Augments Adoptive T Cell Therapy Against Solid Tumors via Diverting Regulatory T Cells

The efficacy of adoptive T cell therapy (ACT) for the treatment of solid tumors remains challenging. In addition to the poor infiltration of effector T (Teff) cells limited by the physical barrier surrounding the solid tumor, another major obstacle is the extensive infiltration of regulatory T (Treg) cells, a major immunosuppressive immune cell subset, in the tumor microenvironment. Here, this work develops a grooved microneedle patch for augmenting ACT, aiming to simultaneously overcome physical and immunosuppressive barriers. The microneedles are engineered through an ice-templated method to generate the grooved structure for sufficient T-cell loading. In addition, with the surface modification of chemokine CCL22, the MNs could not only directly deliver tumor-specific T cells into solid tumors through physical penetration, but also specifically divert Treg cells from the tumor microenvironment to the surface of the microneedles via a cytokine concentration gradient, leading to an increase in the ratio of Teff cells/Treg cells in a mouse melanoma model. Consequently, this local delivery strategy of both T cell receptor T cells and chimeric antigen receptor T cells via the CCL22-modified grooved microneedles as a local niche could significantly enhance the antitumor efficacy and reduce the on-target off-tumor toxicity of ACT.

Organic Semiconducting Sono-Metallo-Detonated Immunobombs for Ultrasensitized Domestication of Immunosuppressive Cells

Cancer immunotherapy harnesses the immune system to combat cancer, yet tumors often evade immune surveillance through immunosuppressive cells. Herein, we report an organic semiconducting sono-metallo-detonated immunobomb (SMIB) to spatiotemporally tame immunosuppressive cells in situ. SMIB consists of an amphiphilic semiconducting polymer (SP) with a repeatable thiophene-based Schiff base serving as an iron ion chelator (Fe3+). SMIB increases sonochemical activity through iron chelation and reduces immunosuppressive cell differentiation with metals and sonochemicals, thereby decreasing the irradiation dose. Upon ultrasound irradiation, SMIB acts as a sono-metallo-detonated immunobomb and inhibits Tregs via the mTOR pathway and M2 macrophage polarization through GPX4 regulation. Ultrasensitized sono-generated reactive oxygen species also promote activation of antigen-presenting cells in deep solid tumors (1 cm), resulting in cytotoxic T cell infiltration and enhanced antitumor efficacy. This platform provides a versatile approach for synergistic sono- and metalloregulation of immunosuppressive cells in situ.

Novel Drug Delivery Systems: An Important Direction for Drug Innovation Research and Development

The escalating demand for enhanced therapeutic efficacy and reduced adverse effects in the pharmaceutical domain has catalyzed a new frontier of innovation and research in the field of pharmacy: novel drug delivery systems. These systems are designed to address the limitations of conventional drug administration, such as abbreviated half-life, inadequate targeting, low solubility, and bioavailability. As the disciplines of pharmacy, materials science, and biomedicine continue to advance and converge, the development of efficient and safe drug delivery systems, including biopharmaceutical formulations, has garnered significant attention both domestically and internationally. This article presents an overview of the latest advancements in drug delivery systems, categorized into four primary areas: carrier-based and coupling-based targeted drug delivery systems, intelligent drug delivery systems, and drug delivery devices, based on their main objectives and methodologies. Additionally, it critically analyzes the technological bottlenecks, current research challenges, and future trends in the application of novel drug delivery systems.

Engineering unactivated platelets for targeted drug delivery

As a vital component of blood, platelets play crucial roles in hemostasis and maintaining vascular integrity, and actively participate in inflammation and immune regulation. The unique biological properties of natural platelets have enabled their utilization as drug delivery vehicles. The advancement and integration of various techniques, including biological, chemical, and physicochemical methods, have enabled the preparation of engineered platelets. Platelets can serve as drug delivery platforms combined with immunotherapy and chemokine therapy to enhance their therapeutic impact. This review focuses on the recent advancements in the application of unactivated platelets for drug delivery. The construction strategies of engineered platelets are comprehensively summarized, encompassing internal loading, surface modification, and genetic engineering techniques. Engineered platelets hold vast potential for treating cardiovascular diseases, cancers, and infectious diseases. Furthermore, the challenges and potential considerations in creating engineered platelets with natural activity are discussed.

Platelet Contributions to the (Pre)metastatic Tumor Microenvironment

Alongside their conventional roles in thrombosis and hemostasis, platelets have long been associated with nonhemostatic pathologies, including tumor cell metastasis. Numerous mechanistic studies have since demonstrated that the direct binding of platelets to intravascular tumor cells promotes key hallmarks of metastasis, including survival in circulation and tumor cell arrest at secondary sites. However, platelets also interact with nonmalignant cells that make up the stromal and immune compartments within both primary and metastatic tumors. This review will first provide a brief historical perspective on platelet contributions to metastatic disease before discussing the emerging roles that platelets play in creating microenvironments that likely support successful tumor cell metastasis.

Engineered platelet-based immune engager for tumor post-surgery treatment

Tumor metastasis and recurrence are principal reasons for the high mortality and poor prognosis of cancers. Inefficient engagement between T cell and tumor cell, as well as the universal existence of immune checkpoints, are important factors to the limited immunological surveillance of the immune systems to tumor cells. Herein, an immune engager based on engineered platelets with CD3 antibody modification (P-aCD3) was constructed to facilitate the contact between T cell and tumor cell via providing the anchoring sites of above two cells. Combined with the immune checkpoint blockade strategy, P-aCD3 effectively enhanced T cell mediated cytotoxicity and inhibited tumor recurrence and metastasis in mice melanoma postoperative model and breast cancer model, resulting in significantly prolonged survival of mice.

Platelet-derived microparticles and their cargos: The past, present and future

All eukaryotic cells can secrete extracellular vesicles, which have a double-membrane structure and are important players in the intercellular communication involved in a variety of important biological processes. Platelets form platelet-derived microparticles (PMPs) in response to activation, injury, or apoptosis. This review introduces the origin, pathway, and biological functions of PMPs and their importance in physiological and pathological processes. In addition, we review the potential applications of PMPs in cancer, vascular homeostasis, thrombosis, inflammation, neural regeneration, biomarkers, and drug carriers to achieve targeted drug delivery. In addition, we comprehensively report on the origin, biological functions, and applications of PMPs. The clinical transformation, high heterogeneity, future development direction, and limitations of the current research on PMPs are also discussed in depth. Evidence has revealed that PMPs play an important role in cell-cell communication, providing clues for the development of PMPs as carriers for relevant cell-targeted drugs. The development history and prospects of PMPs and their cargos are explored in this guidebook.

Tackling Esophageal Squamous Cell Carcinoma with ITFn-Pt(IV): A Novel Fusion of PD-L1 Blockade, Chemotherapy, and T-cell Activation

PD-1/PD-L1 blockade immunotherapy has gained approval for the treatment of a diverse range of tumors; however, its efficacy is constrained by the insufficient infiltration of T lymphocytes into the tumor microenvironment, resulting in suboptimal patient responses. Here, a pioneering immunotherapy ferritin nanodrug delivery system denoted as ITFn-Pt(IV) is introduced. This system orchestrates a synergistic fusion of PD-L1 blockade, chemotherapy, and T-cell activation, aiming to augment the efficacy of tumor immunotherapy. Leveraging genetic engineering approach and temperature-regulated channel-based drug loading techniques, the architecture of this intelligent responsive system is refined. It is adept at facilitating the precise release of T-cell activating peptide Tα1 in the tumor milieu, leading to an elevation in T-cell proliferation and activation. The integration of PD-L1 nanobody KN035 ensures targeted engagement with tumor cells and mediates the intracellular delivery of the encapsulated Pt(IV) drugs, culminating in immunogenic cell death and the subsequent dendritic cell maturation. Employing esophageal squamous cell carcinoma (ESCC) as tumor model, the potent antitumor efficacy of ITFn-Pt(IV) is elucidated, underscored by augmented T-cell infiltration devoid of systemic adverse effects. These findings accentuate the potential of ITFn-Pt(IV) for ESCC treatment and its applicability to other malignancies resistant to established PD-1/PD-L1 blockade therapies.

Targeted platelet with hydrogen peroxide responsive behavior for non-alcoholic steatohepatitis detection

The most common chronic liver illness, non-alcoholic fatty liver disease (NAFLD), refers to a range of abnormalities of the liver with varying degrees of steatosis. When the clinical symptoms including liver damage, inflammation, and fibrosis, are added to the initial steatosis, NAFLD becomes non-alcoholic steatohepatitis (NASH), the problematic and severe stage. The diagnosis of NASH at the right time could therefore effectively prevent deterioration of the disease. Considering that platelets (PLTs) could migrate to the sites of inflamed liver sinusoids with oxidative stress during the development of NASH, we purified the PLTs from fresh blood and engineered their surface with hydrogen peroxide (H2O2) responsive fluorescent probe (5-DP) through lipid fusion. The engineered PLT-DPs were recruited and trapped in the inflammation foci of the liver with NASH through interaction with the extracellular matrix, including hyaluronan and Kupffer cells. Additionally, the fluorescence of 5-DP on the surface of PLT-DP was significantly enhanced upon reacting with the elevated level of H2O2 in the NASH liver. Thus, PLT-DP has great promise for NASH fluorescence imaging with high selectivity and sensitivity.

In situ injectable hydrogel encapsulating Mn/NO-based immune nano-activator for prevention of postoperative tumor recurrence

Postoperative tumor recurrence remains a predominant cause of treatment failure. In this study, we developed an in situ injectable hydrogel, termed MPB-NO@DOX + ATRA gel, which was locally formed within the tumor resection cavity. The MPB-NO@DOX + ATRA gel was fabricated by mixing a thrombin solution, a fibrinogen solution containing all-trans retinoic acid (ATRA), and a Mn/NO-based immune nano-activator termed MPB-NO@DOX. ATRA promoted the differentiation of cancer stem cells, inhibited cancer cell migration, and affected the polarization of tumor-associated macrophages. The outer MnO2 shell disintegrated due to its reaction with glutathione and hydrogen peroxide in the cytoplasm to release Mn2+ and produce O2, resulting in the release of doxorubicin (DOX). The released DOX entered the nucleus and destroyed DNA, and the fragmented DNA cooperated with Mn2+ to activate the cGAS-STING pathway and stimulate an anti-tumor immune response. In addition, when MPB-NO@DOX was exposed to 808 nm laser irradiation, the Fe-NO bond was broken to release NO, which downregulated the expression of PD-L1 on the surface of tumor cells and reversed the immunosuppressive tumor microenvironment. In conclusion, the MPB-NO@DOX + ATRA gel exhibited excellent anti-tumor efficacy. The results of this study demonstrated the great potential of in situ injectable hydrogels in preventing postoperative tumor recurrence.

Engineered platelet cell motors for boosted cancer radiosensitization

Design of engineered cells to target and deliver nanodrugs to the hard-to-reach regions has become an exciting research area. However, the limited penetration and retention of cell-based carriers in tumor tissue restricted their therapeutic efficiency. Inspired by the enhanced delivery behavior of mobile micro/nanomotors, herein, urease-powered platelet cell motors (PLT@Au@Urease) capable of active locomotion, tumor targeting, and radiosensitizers delivery were designed for boosting radiosensitization. The engineered platelet cell motors were constructed by in situ synthesis and loading of radiosensitizers gold nanoparticles in platelets, and then conjugation with urease as the engine. Under physiological concentration of urea, thrust around PLT@Au@Urease motors can be generated via the biocatalytic reactions of urease, leading to rapid tumor cell targeting and enhanced cellular uptake of radiosensitizers. Encouragingly, in comparison with engineered PLT without propulsion capability (PLT@Au), the self-propelled PLT@Au@Urease motors could significantly increase intracellular ROS level and exacerbate nuclear DNA damage induced by γ-radiation, resulting in a remarkably high sensitization enhancement rate (1.89) than that of PLT@Au (1.08). In vivo experiments with 4 T1-bearing mice demonstrated that PLT@Au@Urease in combination with radiation therapy possessed good antitumor performance. Such an intelligent cell motor would provide a promising approach to enhance radiosensitization and broaden the applications of cell motor-based delivery systems.

Recent Biomaterial-Assisted Approaches for Immunotherapeutic Inhibition of Cancer Recurrence

Biomaterials possess distinctive properties, notably their ability to encapsulate active biological products while providing biocompatible support. The immune system plays a vital role in preventing cancer recurrence, and there is considerable demand for an effective strategy to prevent cancer recurrence, necessitating effective strategies to address this concern. This review elucidates crucial cellular signaling pathways in cancer recurrence. Furthermore, it underscores the potential of biomaterial-based tools in averting or inhibiting cancer recurrence by modulating the immune system. Diverse biomaterials, including hydrogels, particles, films, microneedles, etc., exhibit promising capabilities in mitigating cancer recurrence. These materials are compelling candidates for cancer immunotherapy, offering in situ immunostimulatory activity through transdermal, implantable, and injectable devices. They function by reshaping the tumor microenvironment and impeding tumor growth by reducing immunosuppression. Biomaterials facilitate alterations in biodistribution, release kinetics, and colocalization of immunostimulatory agents, enhancing the safety and efficacy of therapy. Additionally, how the method addresses the limitations of other therapeutic approaches is discussed.

Upconversion dual-photosensitizer-expressing bacteria for near-infrared monochromatically excitable synergistic phototherapy

Synergistic phototherapy stands for superior treatment prospects than a single phototherapeutic modality. However, the combined photosensitizers often suffer from incompatible excitation mode, limited irradiation penetration depth, and lack of specificity. We describe the development of upconversion dual-photosensitizer-expressing bacteria (UDPB) for near-infrared monochromatically excitable combination phototherapy. UDPB are prepared by integrating genetic engineering and surface modification, in which bacteria are encoded to simultaneously express photothermal melanin and phototoxic KillerRed protein and the surface primary amino groups are derived to free thiols for biorthogonal conjugation of upconversion nanoparticles. UDPB exhibit a near-infrared monochromatic irradiation-mediated dual-activation characteristic as the photothermal conversion of melanin can be initiated directly, while the photodynamic effect of KillerRed can be stimulated indirectly by upconverted visible light emission. UDPB also show living features to colonize hypoxic lesion sites and inhibit pathogens via bacterial community competition. In two murine models of solid tumor and skin wound infection, UDPB separately induce robust antitumor response and a rapid wound healing effect.

Dual-crosslinking immunostimulatory hydrogel synchronously suppresses pancreatic fistula and pancreatic cancer relapse post-resection

In pancreatic cancer (PC), surgical resection remains the sole curative option, albeit patients undergoing resection are susceptible to postoperative pancreatic fistula (PF) formation and tumor recurrence. An unmet need exists for a unified strategy capable of concomitantly averting PF and tumor relapse to mitigate morbidity in PC patients after surgery. Herein, an original dual crosslinked biological sealant hydrogel (methacrylate-hyaluronic acid-dopamine (MA-HA-DA) and sulfhydryl-hyaluronic acid-dopamine (SH-HA-DA)) was engineered as a drug depot and loaded with polydopamine-cloaked cytokine interleukin-15 and platelets conjugated with anti-TIGIT. In vitro analyses validated favorable tissue adhesion, cytocompatibility, and stability of the hydrogels. In a PF rodent model, the hydrogel effectively adhered to the pancreatic stump, sealing the severed pancreatic end and impeding post-operative elevations in amylase and lipase. In PC murine models, hydrogels potently stimulated CD8+ T and NK cells to deter residual tumor re-growth and distant metastasis. This innovative hydrogel strategy establishes a new framework for concomitant prevention of PF and PC recurrence.

A combination of PD-L1-targeted IL-15 mRNA nanotherapy and ultrasound-targeted microbubble destruction for tumor immunotherapy

PD-1/PD-L1-based immune checkpoint blockade therapy has shown limited benefits in tumor patients, partially attributed to the inadequate infiltration of immune effector cells within tumors. Here, we established a nanoplatform named DPPA/IL-15 NPs to target PD-L1 for the tumor delivery of IL-15 messenger RNA (mRNA). DPPA/IL-15 NPs were endowed with ultrasound responsiveness and contrast-enhanced ultrasound (CEUS) imaging performance. They effectively protected IL-15 mRNA from degradation and specifically transfected it into tumor cells through the utilization of ultrasound-targeted microbubble destruction (UTMD). This resulted in the activation of IL-15-related immune effector cells while blocking the PD-1/PD-L1 pathway. In addition, UTMD could generate reactive oxygen species (ROS) that induce endoplasmic reticulum (ER) stress-driven immunogenic cell death (ICD), initiating anti-tumor immunity. In vitro and in vivo studies revealed that this combination therapy could induce a robust systemic immune response and enhance anti-tumor efficacy. Thus, this combination therapy has the potential for clinical translation through enhanced immunotherapy and provides real-time ultrasound imaging guidance.

Roles of Tumor-Educated Platelets (TEPs) in the biology of Non-Small Cell Lung Cancer (NSCLC): A systematic review. "Re-discovering the neglected biosources of the liquid biopsy family"

Due to their interactions with the neoplasm, platelets undergo various proteomic and transcriptomic modifications, resulting in the development of what is known as the "Tumor-Educated Platelets (TEPs) phenotype". Consequently, in addition to their suitability for Liquid Biopsy (LB) applications, they play a pivotal role in the malignancy by communicating with Circulating Tumor Cells (CTCs), Tumor Microenvironment (TME), and the tumor itself through multiple mechanisms and at multiple levels, ultimately promoting the metastasis of cancer. Therefore, this Systematic Review of MEDLINE and the Cochrane Library present in-depth insights into these phenomena, with the aim of enhancing the understanding of the complex interplay between TEPs and Non-Small Cell Lung Cancer (NSCLC). This endeavor serves to provide context and drive medical research efforts, which are increasingly focused on developing novel diagnostic and therapeutic technologies that leverage the specific binding of these platelets to the disease.

Cell membrane-coated biomimetic nanomedicines: productive cancer theranostic tools

As the second-leading cause of human death, cancer has drawn attention in the area of biomedical research and therapy from all around the world. Certainly, the development of nanotechnology has made it possible for nanoparticles (NPs) to be used as a carrier for delivery systems in the treatment of tumors. This is a biomimetic approach established to craft remedial strategies comprising NPs cloaked with membrane obtained from various natural cells like blood cells, bacterial cells, cancer cells, etc. Here we conduct an in-depth exploration of cell membrane-coated NPs (CMNPs) and their extensive array of applications including drug delivery, vaccination, phototherapy, immunotherapy, MRI imaging, PET imaging, multimodal imaging, gene therapy and a combination of photothermal and chemotherapy. This review article provides a thorough summary of the most recent developments in the use of CMNPs for the diagnosis and treatment of cancer. It critically assesses the state of research while recognizing significant accomplishments and innovations. Additionally, it indicates ongoing problems in clinical translation and associated queries that warrant deeper research. By doing so, this study encourages creative thinking for future projects in the field of tumor therapy using CMNPs while also educating academics on the present status of CMNP research.

Chemotactic Micro/Nanomotors for Biomedical Applications

In nature, many organisms respond chemotactically to external chemical stimuli in order to extract nutrients or avoid danger. Inspired by this natural chemotaxis, micro/nanomotors with chemotactic properties have been developed and applied to study a variety of disease models. This chemotactic strategy has shown promising results and has attracted the attention of an increasing number of researchers. This paper mainly reviews the construction methods of different types of chemotactic micro/nanomotors, the mechanism of chemotaxis, and the potential applications in biomedicine. First, based on the classification of materials, the construction methods and therapeutic effects of chemotactic micro/nanomotors based on natural cells and synthetic materials in cellular and animal experiments will be elaborated in detail. Second, the mechanism of chemotaxis of micro/nanomotors is elaborated in detail: chemical reaction induced chemotaxis and physical process driven chemotaxis. In particular, the main differences and significant advantages between chemotactic micro/nanomotors and magnetic, electrical and optical micro/nanomotors are described. The applications of chemotactic micro/nanomotors in the biomedical fields in recent years are then summarized, focusing on the mechanism of action and therapeutic effects in cancer and cardiovascular disease. Finally, the authors are looking forward to the future development of chemotactic micro/nanomotors in the biomedical fields.

In-situ-sprayed therapeutic hydrogel for oxygen-actuated Janus regulation of postsurgical tumor recurrence/metastasis and wound healing

Surgery is the mainstay of treatment modality for malignant melanoma. However, the deteriorative hypoxic microenvironment after surgery is recognized as a stemming cause for tumor recurrence/metastasis and delayed wound healing. Here we design and construct a sprayable therapeutic hydrogel (HIL@Z/P/H) encapsulating tumor-targeted nanodrug and photosynthetic cyanobacteria (PCC 7942) to prevent tumor recurrence/metastasis while promote wound healing. In a postsurgical B16F10 melanoma model in female mice, the nanodrug can disrupt cellular redox homeostasis via the photodynamic therapy-induced cascade reactions within tumor cells. Besides, the photosynthetically generated O2 by PCC 7942 can not only potentiate the oxidative stress-triggered cell death to prevent local recurrence of residual tumor cells, but also block the signaling pathway of hypoxia-inducible factor 1α to inhibit their distant metastasis. Furthermore, the long-lasting O2 supply and PCC 7942-secreted extracellular vesicles can jointly promote angiogenesis and accelerate the wound healing process. Taken together, the developed HIL@Z/P/H capable of preventing tumor recurrence/metastasis while promoting wound healing shows great application potential for postsurgical cancer therapy.

TME-Related Biomimetic Strategies Against Cancer

The tumor microenvironment (TME) plays an important role in various stages of tumor generation, metastasis, and evasion of immune monitoring and treatment. TME targeted therapy is based on TME components, related pathways or active molecules as therapeutic targets. Therefore, TME targeted therapy based on environmental differences between TME and normal cells has been widely studied. Biomimetic nanocarriers with low clearance, low immunogenicity, and high targeting have enormous potential in tumor treatment. This review introduces the composition and characteristics of TME, including cancer‑associated fibroblasts (CAFs), extracellular matrix (ECM), tumor blood vessels, non-tumor cells, and the latest research progress of biomimetic nanoparticles (NPs) based on TME. It also discusses the opportunities and challenges of clinical transformation of biomimetic nanoparticles.

Oxidized Dextran/Chitosan Hydrogel Engineered with Tetrasulfide-Bridged Silica Nanoparticles for Postsurgical Treatment

Tumor recurrence and wound microbial infection after tumor excision are serious threats to patients. Thus, the strategy to supply a sufficient and sustained release of cancer drugs and simultaneously engineer antibacterial properties and satisfactory mechanical strength is highly desired for tumor postsurgical treatment. Herein, A novel double-sensitive composite hydrogel embedded with tetrasulfide-bridged mesoporous silica (4S-MSNs) is developed. The incorporation of 4S-MSNs into oxidized dextran/chitosan hydrogel network, not only enhances the mechanical properties of hydrogels, but also can increase the specificity of drug with dual pH/redox sensitivity, thereby allowing more efficient and safer therapy. Besides, 4S-MSNs hydrogel preserves the favorable physicochemical properties of polysaccharide hydrogel, such as high hydrophilicity, satisfactory antibacterial activity, and excellent biocompatibility. Thus, the prepared 4S-MSNs hydrogel can be served as an efficient strategy for postsurgical bacterial infection and inhibition of tumor recurrence.