A Near-Infrared Peptide Probe with Tumor-Specific Excretion-Retarded Effect for Image-Guided Surgery of Renal Cell Carcinoma

Effective strategies to enhance the diagnosis and treatment of RCC: The application of biocompatible materials

Renal cell carcinoma (RCC) is recognized as one of the three primary malignant tumors affecting the urinary system, posing a significant risk to human health and life. Despite advancements in understanding RCC, challenges persist in its diagnosis and treatment, particularly in early detection and diagnosis due to issues of low specificity and sensitivity. Consequently, there is an urgent need for the development of effective strategies to enhance diagnostic accuracy and treatment outcomes for RCC. In recent years, with the extensive research on materials for applications in the biomedical field, some materials have been identified as promising for clinical applications, e.g., in the diagnosis and treatment of many tumors, including RCC. Herein, we summarize the latest materials that are being studied and have been applied in the early diagnosis and treatment of RCC. While focusing on their adjuvant effects, we also discuss their technical principles and safety, thus highlighting the value and potential of their application. In addition, we also discuss the limitations of the application of these materials and possible future directions, providing new insights for improving RCC diagnosis and treatment.

A Transformable Specific-Responsive Peptide for One-Step Synergistic Therapy of Bladder Cancer

Synergistic therapy has shown greater advantages compared with monotherapy. However, the complex multiple-administration plan and potential side effects limit its clinical application. A transformable specific-responsive peptide (TSRP) is utilized to one-step achieve synergistic therapy integrating anti-tumor, anti-angiogenesis and immune response. The TSRP is composed of: i) Recognition unit could specifically target and inhibit the biological function of FGFR-1; ii) Transformable unit could self-assembly and trigger nanofibers formation; iii) Reactive unit could specifically cleaved by MMP-2/9 in tumor micro-environment; iv) Immune unit, stimulate the release of immune cells when LTX-315 (Immune-associated oncolytic peptide) exposed. Once its binding to FGFR-1, the TSRP could cleaved by MMP-2/9 to form the nanofibers on the cell membrane, with a retention time of up to 12 h. Through suppressing the phosphorylation levels of ERK 1/2 and PI3K/AKT signaling pathways downstream of FGFR-1, the TSRP significant inhibit the growth of tumor cells and the formation of angioginesis. Furthermore, LTX-315 is exposed after TSRP cleavage, resulting in Calreticulin activation and CD8+ T cells infiltration. All above processes together contribute to the increasing survival rate of tumor-bearing mice by nearly 4-folds. This work presented a unique design for the biological application of one-step synergistic therapy of bladder cancer.

Small Peptide-Based Nanodelivery Systems for Cancer Therapy and Diagnosis

Developing nano-biomaterials with tunable topology, size, and surface characteristics has shown tremendously favorable benefits in various biologic and clinical applications. Among various nano-biomaterials, peptide-based drug delivery systems offer multiple merits over other synthetic systems due to their enhanced bio- and cytocompatibility and desirable biochemical and biophysical properties. Currently, around 100 peptide-based drugs are clinically available for numerous therapeutic purposes. In conjugation with chemotherapeutic moieties, peptides demonstrate a remarkable ability to reduce nonspecific drug effects by improving drug targetability at cancer sites. This review encompasses a wide-ranging role played by different peptide-based nanostructures in cancer theranostics. Section 1 introduces the rising concern about cancer as a disease and further describes peptide-based nanomaterials as biomedical agents to tackle the ailment. The subsequent section explores the mechanistic pathways behind the self-assembly of peptides to form hierarchically distinct assemblies. The crux of our review lies in an exhaustive exploration of the applications of various types of peptide-based nanostructures in cancer therapy and diagnosis. SIGNIFICANCE STATEMENT: Peptide-based drug delivery systems possess superior biocompatibility, biochemical, and biophysical properties compared to other synthetic alternatives. The development of these nano-biomaterials with customizable topology, size, and surface characteristics have shown promising outcomes in biomedical contexts. Peptides in conjunction with chemotherapeutic agents exhibit the ability to enhance drug targetability at cancer sites, reducing nonspecific drug effects. This comprehensive review emphasizes the pivotal role of diverse peptide-based nanostructures as cancer theranostics, elucidating their potential in revolutionizing cancer therapy and diagnosis.

Self-Assembly of Peptides as an Alluring Approach toward Cancer Treatment and Imaging

Cancer is a severe threat to humans, as it is the second leading cause of death after cardiovascular diseases and still poses the biggest challenge in the world of medicine. Due to its higher mortality rates and resistance, it requires a more focused and productive approach to provide the solution for it. Many therapies promising to deliver favorable results, such as chemotherapy and radiotherapy, have come up with more negatives than positives. Therefore, a new class of medicinal solutions and a more targeted approach is of the essence. This review highlights the alluring properties, configurations, and self-assembly of peptide molecules which benefit the traditional approach toward cancer therapy while sparing the healthy cells in the process. As targeted drug delivery systems, self-assembled peptides offer a wide spectrum of conjugation, biocompatibility, degradability-controlled responsiveness, and biomedical applications, including cancer treatment and cancer imaging.

Stimuli-responsive peptide assemblies: Design, self-assembly, modulation, and biomedical applications

Peptide molecules have design flexibility, self-assembly ability, high biocompatibility, good biodegradability, and easy functionalization, which promote their applications as versatile biomaterials for tissue engineering and biomedicine. In addition, the functionalization of self-assembled peptide nanomaterials with other additive components enhances their stimuli-responsive functions, promoting function-specific applications that induced by both internal and external stimulations. In this review, we demonstrate recent advance in the peptide molecular design, self-assembly, functional tailoring, and biomedical applications of peptide-based nanomaterials. The strategies on the design and synthesis of single, dual, and multiple stimuli-responsive peptide-based nanomaterials with various dimensions are analyzed, and the functional regulation of peptide nanomaterials with active components such as metal/metal oxide, DNA/RNA, polysaccharides, photosensitizers, 2D materials, and others are discussed. In addition, the designed peptide-based nanomaterials with temperature-, pH-, ion-, light-, enzyme-, and ROS-responsive abilities for drug delivery, bioimaging, cancer therapy, gene therapy, antibacterial, as well as wound healing and dressing applications are presented and discussed. This comprehensive review provides detailed methodologies and advanced techniques on the synthesis of peptide nanomaterials from molecular biology, materials science, and nanotechnology, which will guide and inspire the molecular level design of peptides with specific and multiple functions for function-specific applications.

Cell Membrane as A Promising Therapeutic Target: From Materials Design to Biomedical Applications

The cell membrane is a crucial component of cells, protecting their integrity and stability while facilitating signal transduction and information exchange. Therefore, disrupting its structure or impairing its functions can potentially cause irreversible cell damage. Presently, the tumor cell membrane is recognized as a promising therapeutic target for various treatment methods. Given the extensive research focused on cell membranes, it is both necessary and timely to discuss these developments, from materials design to specific biomedical applications. This review covers treatments based on functional materials targeting the cell membrane, ranging from well-known membrane-anchoring photodynamic therapy to recent lysosome-targeting chimaeras for protein degradation. The diverse therapeutic mechanisms are introduced in the following sections: membrane-anchoring phototherapy, self-assembly on the membrane, in situ biosynthesis on the membrane, and degradation of cell membrane proteins by chimeras. In each section, we outline the conceptual design or general structure derived from numerous studies, emphasizing representative examples to understand advancements and draw inspiration. Finally, we discuss some challenges and future directions in membrane-targeted therapy from our perspective. This review aims to engage multidisciplinary readers and encourage researchers in related fields to advance the fundamental theories and practical applications of membrane-targeting therapeutic agents.

Nerve Visualization using Phenoxazine-Based Near-Infrared Fluorophores to Guide Prostatectomy

Fluorescence-guided surgery (FGS) is poised to revolutionize surgical medicine through near-infrared (NIR) fluorophores for tissue- and disease-specific contrast. Clinical open and laparoscopic FGS vision systems operate nearly exclusively at NIR wavelengths. However, tissue-specific NIR contrast agents compatible with clinically available imaging systems are lacking, leaving nerve tissue identification during prostatectomy a persistent challenge. Here, it is shown that combining drug-like molecular design concepts and fluorophore chemistry enabled the production of a library of NIR phenoxazine-based fluorophores for intraoperative nerve-specific imaging. The lead candidate readily delineated prostatic nerves in the canine and iliac plexus in the swine using the clinical da Vinci Surgical System that has been popularized for minimally invasive prostatectomy procedures. These results demonstrate the feasibility of molecular engineering of NIR nerve-binding fluorophores for ready integration into the existing surgical workflow, paving the path for clinical translation to reduce morbidity from nerve injury for prostate cancer patients.

JS-K Combined with a Melanin-Based Theranostic Agent: A Novel Sequential Delivery Strategy to Enhance the Near-Infrared Fluorescence Imaging of Pancreatic Ductal Adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is an aggressive malignancy with a 5 year survival rate less than 12%. This malignancy is closely related to the unique tumor microenvironment (TME), which is characterized by a hypovascular and hyperdense extracellular matrix, making it difficult for drugs to permeate the tumor center. Near-infrared fluorescence (NIRF) imaging, which has high sensitivity and resolution, may improve the survival rate of PDAC patients. In this study, we first used JS-K (O2-(2,4-dinitrophenyl) 1-[(4-ethoxycarbonyl) piperazine-1-yl] diazene-1-ium-1,2-diolate) to specifically dilate blood vessels within the TME of PDAC patients and subsequently injected IR820-PEG-MNPs (IPM NPs) to diagnose and treat orthotopic PDAC. We found that JS-K promoted the accumulation of IPM NPs in orthotopic Pan02 tumor-bearing mice and was able to increase the tumor signal-to-background ratio (SBR) in the orthotopic PDAC area by 41.5%. In addition, surgical navigation in orthotopic Pan02 tumor-bearing mice and complete tumor resection based on fluorescence imaging were achieved with a detection sensitivity of 81.0%. Moreover, we verified the feasibility of the combination of laparoscopy and photothermal ablation (PTA) for the treatment of PDAC. Finally, we demonstrated that IPM NPs had greater affinity for human PDAC tissues than for normal pancreatic tissues ex vivo, preliminarily highlighting the potential for clinical translation of these NPs. In conclusion, we developed and validated a novel sequential delivery strategy that promotes the accumulation of nanoagents in the tumor area and can be used for the diagnosis and treatment of PDAC.

Unfolded Protein-Based Sandwich AIE Probe Imparts High Fluorescent Contrast for Pan-Cancer Surgical Navigation

Fluorescence imaging-guided navigation for cancer surgery has a promising clinical application. However, pan-cancer encompasses a wide variety of cancer types with significant heterogeneity, resulting in the lack of universal and highly contrasted fluorescent probes for surgical navigation. Here, we developed an aggregation-induced emission (AIE) probe (MI-AIE-TsG, MAT) with dual activation for pan-cancer surgical navigation. MAT weakly activates fluorescence by targeting the SUR1 protein on the endoplasmic reticulum (ER) through the TsG group. Subsequently, the sulfhydryl groups on the unfolded proteins, which are highly enriched in cancer ER, react with the maleimide (MI) of MAT through the thiol-ene click reaction, further enhancing the fluorescence. The formation of a SUR1-MAT-unfolded protein sandwich complex reinforces the restriction of intramolecular motion and eliminates photoinduced electron transfer of MAT, leading to high signal-to-noise (9.2) fluorescence imaging and use for surgical navigation of pan-cancer. The generally high content of unfolded proteins in cancer cells makes MAT imaging generalizable, and it currently has proven feasibility in ovarian, cervical, and breast cancers. Meanwhile, MAT promotes cellular autophagy by hindering protein folding, thereby inhibiting cancer cell proliferation. This generalizable, high-contrast AIE fluorescent probe spans the heterogeneity of pancreatic cancer, enabling precise pancreatic cancer surgery navigation and treatment.

Multistage Self-Assembled Nanomaterials for Cancer Immunotherapy

Advances in nanotechnology have brought innovations to cancer therapy. Nanoparticle-based anticancer drugs have achieved great success from bench to bedside. However, insufficient therapy efficacy due to various physiological barriers in the body remains a key challenge. To overcome these biological barriers and improve the therapeutic efficacy of cancers, multistage self-assembled nanomaterials with advantages of stimuli-responsiveness, programmable delivery, and immune modulations provide great opportunities. In this review, we describe the typical biological barriers for nanomedicines, discuss the recent achievements of multistage self-assembled nanomaterials for stimuli-responsive drug delivery, highlighting the programmable delivery nanomaterials, in situ transformable self-assembled nanomaterials, and immune-reprogramming nanomaterials. Ultimately, we perspective the future opportunities and challenges of multistage self-assembled nanomaterials for cancer immunotherapy.

Celebrating 20 Years of NCNST: Innovation in Nanoscience and Nanotechnology

With the development of nanoscience and technology, it has become an essential part of various research directions, changing our way of life, such as advanced accurate manufacturing in nanotechnology that facilitates reducing chip sizes, progress made in health care via nanoscience that provides hope to patients, and so on. As the nation's flagship institution of nanoscience and technology in China, the National Center for Nanoscience and Technology, China (NCNST), established in December 2003, has played a crucial role in promoting cutting-edge technologies in the field of nanoscience and expediting interdisciplinary fusion. With a strong research team and state-of-the-art research equipment, NCNST currently carries out frontier research and world-class technology innovation, including nanosystems and hierarchical fabrication, biological effects of nanomaterials and nanosafety, standardization and measurements for nanotechnology, as well as theoretical simulations. Serving as one of the most prestigious institutions in nanoscience and nanotechnology in China, NCNST will continue to foster impactful international cooperation, cultivate young talents, and boost inspiring innovation.

Activatable probes with potential for intraoperative tumor-specific fluorescence-imaging guided surgery

Owing to societal development and aging population, the impact of cancer on human health and quality of life has increased. Early detection and surgical treatment are the most effective approaches for most cancer patients. As the scope of conventional tumor resection is determined by auxiliary examination and surgeon experience, there is often insufficient recognition of tiny tumors. The ability to detect such tumors can be improved by using fluorescent tumor-specific probes for surgical navigation. This review mainly describes the design principles and mechanisms of activatable probes for the fluorescence imaging of tumors. This type of probe is nonfluorescent in normal tissue but exhibits obvious fluorescence emission upon encountering tumor-specific substrates, such as enzymes or bioactive molecules, or changes in the microenvironment, such as a low pH. In some cases, a single-factor response does not guarantee the effective fluorescence labeling of tumors. Therefore, two-factor-activatable fluorescence imaging probes that react with two specific factors in tumor cells have also been developed. Compared with single biomarker testing, the simultaneous monitoring of multiple biomarkers may provide additional insight into the role of these substances in cancer development and aid in improving the accuracy of early cancer diagnosis. Research and progress in this field can provide new methods for precision medicine and targeted therapy. The development of new approaches for early diagnosis and treatment can effectively improve the prognosis of cancer patients and help enhance their quality of life.

Biomedical applications of magnetosomes: State of the art and perspectives

Magnetosomes, synthesized by magnetotactic bacteria (MTB), have been used in nano- and biotechnological applications, owing to their unique properties such as superparamagnetism, uniform size distribution, excellent bioavailability, and easily modifiable functional groups. In this review, we first discuss the mechanisms of magnetosome formation and describe various modification methods. Subsequently, we focus on presenting the biomedical advancements of bacterial magnetosomes in biomedical imaging, drug delivery, anticancer therapy, biosensor. Finally, we discuss future applications and challenges. This review summarizes the application of magnetosomes in the biomedical field, highlighting the latest advancements and exploring the future development of magnetosomes.

A Self-Assembled Organic Probe with Activatable Near-Infrared Fluoro-Photoacoustic Signals for In Vivo Evaluation of the Radiotherapy Effect

Early evaluation and prediction of the radiotherapy effect against tumors are crucial for effective radiotherapy management. The clinical approach generally relies on anatomical changes in tumor size, which is unable to promptly reflect clinical outcomes and guide a timely adjustment of therapy regimens. To resolve it, we herein develop a self-assembled organic probe (dCyFFs) with caspase-3 (Casp-3)-activatable near-infrared (NIR) fluoro-photoacoustic signals for early evaluation and prediction of radiotherapy efficacy. The probe contains an NIR dye that is caged with a Casp-3-cleavable substrate and linked to a self-assembly initiating moiety. In the presence of Casp-3, the self-assembled probe can undergo secondary assembly into larger nanoparticles and simultaneously activate NIR fluoro-photoacoustic signals. Such a design endows a superior real-time longitudinal imaging capability of Casp-3 generated by radiotherapy as it facilitates the passive accumulation of the probe into tumors, activated signal output with enhanced optical stability, and retention capacity relative to a nonassembling small molecular control probe (dCy). As a result, the probe enables precise prediction of the radiotherapy effect as early as 3 h posttherapy, which is further evidenced by the changes in tumor size after radiotherapy. Overall, the probe with Casp-3-mediated secondary assembly along with activatable NIR fluoro-photoacoustic signals holds great potential for evaluating and predicting the response of radiotherapy in a timely manner, which can also be explored for utilization in other therapeutic modalities.

Photostable Cascade-Activatable Peptide Self-Assembly on a Cancer Cell Membrane for High-Performance Identification of Human Bladder Cancer

Missed or residual tumor burden results in high risk for bladder cancer relapse. However, existing fluorescent probes cannot meet the clinical needs because of inevitable photobleaching properties. Performance can be improved by maintaining intensive and sustained fluorescence signals via resistance to intraoperative saline flushing and intrinsic fluorescent decay, providing surgeons with sufficiently clear and high-contrast surgical fields, avoiding residual tumors or missed diagnosis. This study designs and synthesizes a photostable cascade-activatable peptide, a target reaction-induced aggregation peptide (TRAP) system, which can construct polypeptide-based nanofibers in situ on the cell membrane to achieve long-term and stable imaging of bladder cancer. The probe has two parts: a target peptide (TP) targets CD44v6 to recognize bladder cancer cells, and a reaction-induced aggregation peptide (RAP) is introduced, which effectively reacts with the TP via a click reaction to enhance the hydrophobicity of the whole molecule, assembling into nanofibers and further nanonetworks. Accordingly, probe retention on the cell membrane is prolonged, and photostability is significantly improved. Finally, the TRAP system is successfully employed in the high-performance identification of human bladder cancer in ex vivo bladder tumor tissues. This cascade-activatable peptide molecular probe based on the TRAP system enables efficient and stable imaging of bladder cancer.

In situ stimulus-responsive self-assembled nanomaterials for drug delivery and disease treatment

The individual motifs that respond to specific stimuli for the self-assembly of nanomaterials play important roles. In situ constructed nanomaterials are formed spontaneously without human intervention and have promising applications in bioscience. However, due to the complex physiological environment of the human body, designing stimulus-responsive self-assembled nanomaterials in vivo is a challenging problem for researchers. In this article, we discuss the self-assembly principles of various nanomaterials in response to the tissue microenvironment, cell membrane, and intracellular stimuli. We propose the applications and advantages of in situ self-assembly in drug delivery and disease diagnosis and treatment, with a focus on in situ self-assembly at the lesion site, especially in cancer. Additionally, we introduce the significance of introducing exogenous stimulation to construct self-assembly in vivo. Based on this foundation, we put forward the prospects and possible challenges in the field of in situ self-assembly. This review uncovers the relationship between the structure and properties of in situ self-assembled nanomaterials and provides new ideas for innovative drug molecular design and development to solve the problems in the targeted delivery and precision medicine.

Enzyme-Instructed Aggregation/Dispersion of Fluorophores for Near-Infrared Fluorescence Imaging In Vivo

Near-infrared (NIR) fluorescence is a noninvasive, highly sensitive, and high-resolution modality with great potential for in vivo imaging. Compared with "Always-On" probes, activatable NIR fluorescent probes with "Turn-Off/On" or "Ratiometric" fluorescent signals at target sites exhibit better signal-to-noise ratio (SNR), wherein enzymes are one of the ideal triggers for probe activation, which play vital roles in a variety of biological processes. In this review, we provide an overview of enzyme-activatable NIR fluorescent probes and concentrate on the design strategies and sensing mechanisms. We focus on the aggregation/dispersion state of fluorophores after the interaction of probes and enzymes and finally discuss the current challenges and provide some perspective ideas for the construction of enzyme-activatable NIR fluorescent probes.

Molecularly Stimuli-Responsive Self-Assembled Peptide Nanoparticles for Targeted Imaging and Therapy

Self-assembly has emerged as an extensively used method for constructing biomaterials with sizes ranging from nanometers to micrometers. Peptides have been extensively investigated for self-assembly. They are widely applied owing to their desirable biocompatibility, biodegradability, and tunable architecture. The development of peptide-based nanoparticles often requires complex synthetic processes involving chemical modification and supramolecular self-assembly. Stimuli-responsive peptide nanoparticles, also termed "smart" nanoparticles, capable of conformational and chemical changes in response to stimuli, have emerged as a class of promising materials. These smart nanoparticles find a diverse range of biomedical applications, including drug delivery, diagnostics, and biosensors. Stimuli-responsive systems include external stimuli (such as light, temperature, ultrasound, and magnetic fields) and internal stimuli (such as pH, redox environment, salt concentration, and biomarkers), facilitating the generation of a library of self-assembled biomaterials for biomedical imaging and therapy. Thus, in this review, we mainly focus on peptide-based nanoparticles built by self-assembly strategy and systematically discuss their mechanisms in response to various stimuli. Furthermore, we summarize the diverse range of biomedical applications of peptide-based nanomaterials, including diagnosis and therapy, to demonstrate their potential for medical translation.

An "AND" Molecular Logic Gate as a Super-Enhancers for De Novo Designing Activatable Probe and Its Application in Atherosclerosis Imaging

Developing activatable fluorescent probes with superlative fluorescence enhancement factor (F/F0 ) to improve the signal-to-noise (S/N) ratio is still an urgent issue. "AND" molecular logic gates are emerging as a useful tool for enhanced probes selectivity and accuracy. Here, an "AND" logic gate is developed as super-enhancers for designing activatable probes with huge F/F0 and S/N ratio. It utilizes lipid-droplets (LDs) as controllable background input and sets the target analyte as variable input. The fluorescence is tremendously quenching due to double locking, thus an extreme F/F0 ratio of target analyte is obtained. Importantly, this probe can transfer to LDs after a response occurs. The target analyte can be directly visualized through the spatial location without a control group. Accordingly, a peroxynitrite (ONOO- ) activatable probe (CNP2-B) is de novo designed. The F/F0 of CNP2-B achieves 2600 after reacting with ONOO- . Furthermore, CNP2-B can transfer from mitochondria to lipid droplets after being activated. The higher selectivity and S/N ratio of CNP2-B are obtained than commercial probe 3'-(p-hydroxyphenyl) fluorescein (HPFin vitro and in vivo. Therefore, the atherosclerotic plaques at mouse models are delineated clearly after administration with in situ CNP2-B probe gel. Such input controllable "AND" logic gate is envisioned to execute more imaging tasks.

Activatable fluorescent probes for real-time imaging-guided tumor therapy

Surgery and drug therapy are the two principal options for cancer treatment. However, their clinical benefits are hindered by the difficulty of accurate location of the tumors and timely monitoring of the treatment efficacy of drugs, respectively. Rapid development of imaging techniques provides promising tools to address these challenges. Compared with conventional imaging techniques such as magnetic resonance imaging and computed tomography etc., fluorescence imaging exhibits high spatial resolution, real-time imaging capability, and relatively low costs devices. The advancements in fluorescent probes further accelerate the implementation of fluorescence imaging in tumor diagnosis and treatment monitoring. In particular, the emergence of site-specifically activatable fluorescent probes fits the demands of tumor delineation and real-time feedback of the treatment efficacy. A variety of small molecule probes or nanoparticle-based probes have been developed and explored for the above-mentioned applications. This review will discuss recent advances in fluorescent probes with a special focus on activatable nanoprobes and highlight the potential implementation of activatable nanoprobes in fluorescence imaging-guided surgery as well as imaging-guided drug therapy.

PKM2 allosteric converter: A self-assembly peptide for suppressing renal cell carcinoma and sensitizing chemotherapy

Stronger intrinsic Warburg effect and resistance to chemotherapy are the responses to high mortality of renal cell carcinoma (RCC). Pyruvate kinase M2 (PKM2) plays an important role in this process. Promoting PKM2 conversion from dimer to tetramer is a critical strategy to inhibit Warburg effect and reverse chemotherapy resistance. Herein, a PKM2 allosteric converter (PAC) is constructed based on the "in vivo self-assembly" strategy, which is able to continuously stimulate PKM2 tetramerization. The PAC contains three motifs, a serine site that is protected by enzyme cleavable β-N-acetylglucosamine, a self-assembly peptide and a AIE motif. Once PAC nanoparticles reach tumor site via the EPR effect, the protective and hydrophilic β-N-acetylglucosamine will be removed by over-expressed O-GlcNAcase (OGA), causing self-assembled peptides to transform into nanofibers with large serine (PKM2 tetramer activator) exposure and long-term retention, which promotes PKM2 tetramerization continuously. Our results show that PAC-induced PKM2 tetramerization inhibits aberrant metabolism mediated by Warburg effect in cytoplasm. In this way, tumor proliferation and metastasis behavior could be effectively inhibited. Meanwhile, PAC induced PKM2 tetramerization impedes the nuclear translocation of PKM2 dimer, which restores the sensitivity of cancer cells to first-line anticancer drugs. Collectively, the innovative PAC effectively promotes PKM2 conversion from dimer to tetramer, and it might provide a novel approach for suppressing RCC and enhancing chemotherapy sensitivity.

A bispecific glycopeptide spatiotemporally regulates tumor microenvironment for inhibiting bladder cancer recurrence

Up to 75% of bladder cancer patients suffer from recurrence due to postoperative tumor implantation. However, clinically used Bacillus Calmette-Guerin (BCG) treatment failed to inhibit the recurrence. Here, we report a bispecific glycopeptide (bsGP) that simultaneously targets CD206 on tumor-associated macrophages (TAMs) and CXCR4 on tumor cells. bsGP repolarizes protumoral M2-like TAMs to antitumor M1-like that mediated cytotoxicity and T cell recruitment. Meanwhile, bsGP is cleaved by the MMP-2 enzyme to form nanostructure for the long-term inhibition of CXCR4 downstream signaling, resulting in reduced tumor metastasis and promoted T cell infiltration. In orthotopic bladder tumor models, bsGP reduced the postoperative recurrence rate to 22%. In parallel, the recurrence rates of 89 and 78% were treated by doxycycline and BCG used in clinic, respectively. Mechanistic studies reveal that bsGP reduces the matrix microenvironment barrier, increasing the spatially redirected CD8⁺ T cells to tumor cells. We envision that bis-targeting CD206 and CXCR4 may pave the way to inhibit tumor metastasis and recurrence.

Multifunctional Self-Assembled Peptide Hydrogels for Biomedical Applications

Self-assembly is a growth mechanism in nature to apply local interactions forming a minimum energy structure. Currently, self-assembled materials are considered for biomedical applications due to their pleasant features, including scalability, versatility, simplicity, and inexpensiveness. Self-assembled peptides can be applied to design and fabricate different structures, such as micelles, hydrogels, and vesicles, by diverse physical interactions between specific building blocks. Among them, bioactivity, biocompatibility, and biodegradability of peptide hydrogels have introduced them as versatile platforms in biomedical applications, such as drug delivery, tissue engineering, biosensing, and treating different diseases. Moreover, peptides are capable of mimicking the microenvironment of natural tissues and responding to internal and external stimuli for triggered drug release. In the current review, the unique characteristics of peptide hydrogels and recent advances in their design, fabrication, as well as chemical, physical, and biological properties are presented. Additionally, recent developments of these biomaterials are discussed with a particular focus on their biomedical applications in targeted drug delivery and gene delivery, stem cell therapy, cancer therapy and immune regulation, bioimaging, and regenerative medicine.

Nanomedicine for renal cell carcinoma: imaging, treatment and beyond

The kidney is a vital organ responsible for maintaining homeostasis in the human body. However, renal cell carcinoma (RCC) is a common malignancy of the urinary system and represents a serious threat to human health. Although the overall survival of RCC has improved substantially with the development of cancer diagnosis and management, there are various reasons for treatment failure. Firstly, without any readily available biomarkers, timely diagnosis has been greatly hampered. Secondly, the imaging appearance also varies greatly, and its early detection often remains difficult. Thirdly, chemotherapy has been validated as unavailable for treating renal cancer in the clinic due to its intrinsic drug resistance. Concomitant with the progress of nanotechnological methods in pharmaceuticals, the management of kidney cancer has undergone a transformation in the recent decade. Nanotechnology has shown many advantages over widely used traditional methods, leading to broad biomedical applications ranging from drug delivery, prevention, diagnosis to treatment. This review focuses on nanotechnologies in RCC management and further discusses their biomedical translation with the aim of identifying the most promising nanomedicines for clinical needs. As our understanding of nanotechnologies continues to grow, more opportunities to improve the management of renal cancer are expected to emerge.

Micro-Ultrasound in the Diagnosis and Staging of Prostate and Bladder Cancer: A Comprehensive Review

Background and Objectives: Multiparametric magnetic resonance imaging (mpMRI) of the prostate and prostate-specific membrane antigen positron emission tomography (PSMA PET) are some examples of how the advancement of imaging techniques have revolutionized the diagnosis, staging, and consequently management of patients with prostate cancer (PCa). Although with less striking results, novel radiological modalities have also been proposed for bladder cancer (BCa) in recent years. Micro-ultrasound (MUS) is an imaging examination characterized by high real-time spatial resolution, recently introduced in the urological field. This article aimed to describe the current evidence regarding the application of MUS for the diagnosis and staging of PCa and BCa. Materials and Methods: We designed a narrative review. A comprehensive search in the MEDLINE, Scopus, and Cochrane Library databases was performed. Articles in English-language and published until July 2022 were deemed eligible. Retrospective and prospective primary clinical studies, as well as meta-analyses, were included. Results: MUS-guided prostate biopsy showed high sensitivity (0.91, 95% CI, 0.79-0.97) in the diagnosis of clinically significant PCa (csPCa). It was associated with a higher detection rate of csPCa than a systematic biopsy (1.18, 95% CI 0.83-1.68). No significant difference was found between MUS and mpMRI-guided biopsy in the total detection of PCa (p = 0.89) and in the detection of Grade Groups ≥ 2 (p = 0.92). The use of MUS to distinguish between non-muscle-invasive and muscle-invasive BCa was described, highlighting an up-staging with MUS only in a minority of cases (28.6%). Conclusions: Promising findings have emerged regarding the feasibility and accuracy of MUS in the diagnosis and staging of PCa and BCa. However, the available evidence is limited and should be considered preliminary.

Intracellular Enzyme-Instructed Self-Assembly of Peptides (IEISAP) for Biomedical Applications

Despite the remarkable significance and encouraging breakthroughs of intracellular enzyme-instructed self-assembly of peptides (IEISAP) in disease diagnosis and treatment, a comprehensive review that focuses on this topic is still desirable. In this article, we carefully review the advances in the applications of IEISAP, including the development of various bioimaging techniques, such as fluorescence imaging, photoacoustic imaging, magnetic resonance imaging, positron-emission tomography imaging, radiation imaging, and multimodal imaging, which are successfully leveraged in visualizing cancer tissues and cells, bacteria, and enzyme activity. We also summarize the utilization of IEISAP in disease treatments, including anticancer, antibacterial, and antiinflammation applications, among others. We present the design, action modes, structures, properties, functions, and performance of IEISAP materials, such as nanofibers, nanoparticles, nanoaggregates, and hydrogels. Finally, we conclude with an outlook towards future developments of IEISAP materials for biomedical applications. It is believed that this review may foster the future development of IEISAP with better performance in the biomedical field.

Transformable ECM Deprivation System Effectively Suppresses Renal Cell Carcinoma by Reversing Anoikis Resistance and Increasing Chemotherapy Sensitivity

Extracellular matrix (ECM) is crucial in various biological functions during tumor progression, including induction of anoikis resistance and cell adhesion-mediated drug resistance (CAM-DR). Fibronectin (FN) is a vital ECM component with direct regulatory effects on ECM-mediated anoikis resistance and CAM-DR, making it an attractive and innovative therapeutic target for depriving ECM in tumor tissue. Herein, an ECM deprivation system (EDS) is developed based on FN targeting self-assembly peptide for constructing nanofibers in the ECM of renal cell carcinoma (RCC), which contributes to: i) targeting and recognizing FN to form nanofibers for long-term retention in ECM, ii) reversing anoikis resistance via arresting the FN signaling pathway, and iii) serving as a drug-loading platform for sensitizing chemotherapy by ameliorating CAM-DR. The results reveal that EDS significantly reverses anoikis resistance of RCC cells by inhibiting the phosphorylation of FAK, a positive regulator of the FN signaling pathway. Meanwhile, EDS serves as a chemotherapy-sensitizer of cancer, exerting significant synergistic effects with doxorubicin (DOX). In vivo validation experiments show that EDS effectively suppresses metastasis and tumor growth with chemotherapy resistance. Collectively, the innovative EDS notably inhibits the tumor-promoting effect of ECM and may provide a novel approach for suppressing ECM and enhancing chemo-drug sensitivity.

Programmable design and self assembly of peptide conjugated AIEgens for biomedical applications

Aggregation-induced emission luminogens (AIEgens) possess enhanced fluorescence in highly aggregated states, thus enabling AIEgens as a promising module for highly emissive fluorescence biomaterials. So far, AIEgens-based nanomaterials and their hybrids have been reported for biomedical applications. Benefiting from the intrinsic biocompatibility and biofunction-editing properties of peptides, peptide-AIEgens hybrid biomaterials reveal unlimited possibilities including target capacity, specificity, stimuli-responsiveness, self-assembly, controllable structural transformation, etc.. In the last two decades, peptide-AIEgens hybrid nanomaterials with a unique design concept in aggregated states have achieved various biomedical applications such as biosensing, bioimaging, imaging-guided surgery, drug delivery and therapy. More recently, programmable design of peptide-AIEgens for in situ self-assembly provides a unique strategy for constructing intelligent entities with defined biological functions. In this review, we summarize the basic design principle of programmable peptide-AIEgens, structure-effect relationship and their unusual biomedical effects. Finally, an outlook and perspective toward future challenges and developments of peptide-AIEgens nanomaterials are concluded.

Enhancing the Contrast of Tumor Imaging for Image-Guided Surgery Using a Tumor-Targeting Probiotic with the Continuous Expression of a Biomarker

Tumor recurrence commonly results from tumor-positive resection margins and metastatic lesions. The complete removal of tumor-positive margins is particularly essential in clinics. Thus, we designed a strategy based on Escherichia coli Nissle 1917 (EcN) nitroreductase (NTR) with a polyethylene glycol (PEG) polymer coating (PC-EcN-NTR) to specifically target and colonize in tumors for high-contrast tumor imaging by providing a large amount of NTR as biomarkers in situ. NTR is a favorable biomarker for tumor detection and imaging. The nfsB-encoding plasmid with a 16S promoter was transfected into EcN for the continuous and stable expression of NTR (E. coli. NfsB). PC-EcN-NTR can accumulate and proliferate for a long time in tumors to substantially express NTR. When the NTR-activated fluorescence (FL) probe was sprayed on the tumor, the tumor region showed fluorescence signals within 5 min. Compared to the tumor without colonization with bacteria, the PC-EcN-NTR-colonized tumors displayed 3.15× enhanced fluorescence signals. Furthermore, the fluorescence signals of the whole tumor can last at least 3 h, which is suitable for a long and meticulous surgical operation. More importantly, in the PC-EcN-NTR-harboring tumor, obvious FL appeared even at the very edge (approximately 200 μm away from the edge) of the tumor tissue. A TCF-Based near-infrared-II fluorescent probe (probe 2) was designed and synthesized. Results similar to those of probe 1 were observed when probe 2 was used for in vivo tumor imaging, which further proved the generality of the enhancing ability of the tumor-targeting probiotic. This strategy will hopefully guide the surgical resection of tumors via monitoring intense NTR activity. It may spur the use of tumor-targeting probiotic and enzyme-activated fluorescent probes for the processes of tumor diagnosis and image-guided surgery.

In situ self-assembled peptide enables effective cancer immunotherapy by blockage of CD47

Treatment of late-stage lung cancer has witnessed limited advances. In contrast to the tremendous efforts toward improving adaptive immunity, approaches to modulating innate immunity are relatively immature. As important innate immune cells, tumor-associated macrophages (TAMs) account for a substantial fraction of tumor-infiltrating lymphocytes, which not only reverses the immune-suppressive tumor microenvironment but also facilitates an adaptive immune response. In this study, we developed a tumor-specific MMP-2-responsive CD47 blockage (TMCB) strategy to enable effective cancer immunotherapy. Briefly, the matrix metalloproteinase-2 (MMP-2)-responsive self-assembly peptide specifically recognizes CD47, which is highly expressed in lung tumor cells. Second, the MMP-2-responsive self-assembly peptide is efficiently cleaved by MMP-2, which is overexpressed in the tumor microenvironment. Finally, the generated residual peptide naturally self-assembles into peptide-based nanofibers. The in situ constructed nanofibers inhibit the canonical CD47 "Do not eat me" signal expressed on tumor cells to promote phagocytosis of tumor cells by macrophages, which further induces effective antigen presentation and initiates T cell-mediated adaptive immune responses to inhibit tumor growth. Thus, we described a peptide-based TMCB strategy that induces both innate and adaptive immune systems to inhibit tumor growth.

Near-Infrared Fluorescence Imaging of Renal Cell Carcinoma with ASP5354 in a Mouse Model for Intraoperative Guidance

Renal cell carcinoma is a prevalent disease associated with high morbidity and mortality rates. Partial nephrectomy is a first-line surgical option because it allows the preservation of renal function. Clear differentiation between normal and cancerous tissues is critical for increasing the negative margin rates. This study investigated the capability of the near-infrared (NIR) fluorescent imaging agent ASP5354 for in vivo fluorescence imaging of renal cell carcinoma. ASP5354 at a single dose of 12 nmol (0.037 mg)/kg body weight was intravenously administered to healthy and orthotopic renal cell carcinoma mice under anesthesia. NIR images of the abdominal cavity were obtained using a near-infrared fluorescence (NIRF) camera system. In addition, the cancerous kidneys were harvested, and the NIRF in their sections was measured using an NIRF microscope. Normal renal tissue emitted strong NIRF but the cancer tissue did not. The difference in NIRF intensity between the normal and cancer tissues clearly presented the boundary between the normal and cancer tissues in macro and micro NIRF imaging. ASP5354 can distinguish cancer tissue from normal tissue using NIRF. Thus, ASP5354 is a promising agent for renal cell carcinoma tissue imaging in partial nephrectomy for renal cell carcinoma patients.

Nanomedicine for urologic cancers: diagnosis and management

Urologic cancers accounted for more than 2 million new cases and around 0.8 million deaths in 2020. Although surgery, chemotherapy, and radiotherapy, as well as castration for prostate cancer, remain the cornerstones for managing urologic neoplasms, they can result in severe adverse effects, poor patient compliance, and unsatisfactory survival rates, thus, it is essential to develop novel options that enable the early detection of these malignancies, together with providing accurate diagnoses, and more efficient treatment strategies. Nanomedicine represents an emerging approach that can deliver formulations or drugs across traditional biological barriers in the body and be directed to specific cell types within target organs via active targeting or passive targeting, thus, showing potential to improve the management of urologic cancers. In this review, we discussed the most recent updates on the application of nanomedicines in the diagnosis and treatment of urologic cancers, with focus on prostate, bladder and kidney tumors. We also presented the anti-tumor molecular mechanisms of newly designed nanomedicine for treating urologic cancers, mainly including image-guided surgery, chemotherapy, radiotherapy, gene therapy, immunotherapy, and their synergetic therapy. Current studies have demonstrated the potential advantages of nanomedicine over conventional approaches. However, most developments and new findings in this area have not been validated in clinical trials yet, and therefore, efforts shall be made to translate these research insights into clinical practices for urologic cancers.

A Lysosome-Targeting Self-Condensation Prodrug-Nanoplatform System for Addressing Drug Resistance of Cancer

Lysosome-targeting self-assembling prodrugs had emerged as an attractive approach to overcome the acquisition of resistance to chemotherapeutics by inhibiting lysosomal sequestration. Taking advantage of lysosomal acidification induced intracellular hydrolytic condensation, we developed a lysosomal-targeting self-condensation prodrug-nanoplatform (LTSPN) system for overcoming lysosome-mediated drug resistance. Briefly, the designed hydroxycamptothecine (HCPT)-silane conjugates self-assembled into silane-based nanoparticles, which were taken up into lysosomes by tumor cells. Subsequently, the integrity of the lysosomal membrane was destructed because of the acid-triggered release of alcohol, wherein the nanoparticles self-condensed into silicon particles outside the lysosome through intracellular hydrolytic condensation. Significantly, the LTSPN system reduced the half-maximal inhibitory concentration (IC₅₀) of HCPT by approximately 4 times. Furthermore, the LTSPN system realized improved control of large established tumors and reduced regrowth of residual tumors in several drug-resistant tumor models. Our findings suggested that target destructing the integrity of the lysosomal membrane may improve the therapeutic effects of chemotherapeutics, providing a potent treatment strategy for malignancies.

In Situ Constructed Nano-Drug Depots through Intracellular Hydrolytic Condensation for Chemotherapy of Bladder Cancer

Intravesical administration of first-line drugs has shown failure in the treatment of bladder cancer owing to the poor tumor retention time of chemotherapeutics. Herein, we report an intracellular hydrolytic condensation (IHC) system to construct long-term retentive nano-drug depots in situ, wherein sustained drug release results in highly efficient suppression of bladder cancer. Briefly, the designed doxorubicin (Dox)-silane conjugates self-assemble into silane-based prodrug nanoparticles, which condense into silicon particle-based nano-drug depots inside tumor cells. Significantly, we demonstrate that the IHC system possesses highly potent antitumor efficacy, which leads to the regression and eradication of large established tumors and simultaneously extends the overall survival of air pouch bladder cancer mice compared with that of mice treated with Dox. The concept of intracellular hydrolytic condensation can be extended via conjugating other chemotherapeutic drugs, which may facilitate rational design of novel nanomedicines for augmentation of chemotherapy.

Supramolecular Nanomedicines of In-Situ Self-Assembling Peptides

Nanomedicines provide distinct clinical advantages over traditional monomolecular therapeutic and diagnostic agents. Supramolecular nanomedicines made from in-situ self-assembling peptides have emerged as a promising strategy in designing and fabricating nanomedicines. In-situ self-assambly (SA) allows the combination of nanomedicines approach with prodrug approach, which exhibited both advantages of these strategies while addressed the problems of both and thus receiving more and more research attention. In this review, we summarized recently designed supramolecular nanomedicines of in-situ SA peptides in the manner of applications and design principles, and the interaction between the materials and biological environments was also discussed.

Lipid-Activatable Fluorescent Probe for Intraoperative Imaging of Atherosclerotic Plaque Using In Situ Patch

The surgical removal of lesions is among the most common and effective treatments for atherosclerosis. It is often the only curative treatment option, and the ability to visualize the full extent of atherosclerotic plaque during the operation has major implications for the therapeutic outcome. Fluorescence imaging is a promising approach for the inspection of atherosclerotic plaques during surgery. However, there is no systematic strategy for intraoperative fluorescent imaging in atherosclerosis. In this study, the in situ attachment of a lipid-activatable fluorescent probe (CN-N2)-soaked patch to the outer arterial surface is reported for rapid and precise localization of the atherosclerotic plaque in ApoE-deficient mouse during surgery. Stable imaging of the plaque is conducted within 5 min via rapid recognition of abnormally accumulated lipid droplets (LDs) in foam cells. Furthermore, the plaque/normal ratio (P/N) is significantly enhanced to facilitate surgical delineation of carotid atherosclerotic plaques. Visible fluorescence bioimaging using lipid-activatable probes can accurately delineate plaque sizes down to diameters of <0.5 mm, and the images can be swiftly captured within the stable plaque imaging time window. These findings on intraoperative fluorescent imaging of plaques via the in situ attachment of the CN-N2 patch hold promise for effective clinical applications.

A bioactivated in vivo assembly nanotechnology fabricated NIR probe for small pancreatic tumor intraoperative imaging

Real-time imaging of the tumour boundary is important during surgery to ensure that sufficient tumour tissue has been removed. However, the current fluorescence probes for bioimaging suffer from poor tumour specificity and narrow application of the imaging window used. Here, we report a bioactivated in vivo assembly (BIVA) nanotechnology, demonstrating a general optical probe with enhanced tumour accumulation and prolonged imaging window. The BIVA probe exhibits active targeting and assembly induced retention effect, which improves selectivity to tumours. The surface specific nanofiber assembly on the tumour surface increases the accumulation of probe at the boundary of the tumor. The blood circulation time of the BIVA probe is prolonged by 110 min compared to idocyanine green. The assembly induced metabolic stability broaden the difference between the tumor and background, obtaining a delayed imaging window between 8-96 h with better signal-to-background contrast (>9 folds). The fabricated BIVA probe permits precise imaging of small sized (<2 mm) orthotopic pancreatic tumors in vivo. The high specificity and sensitivity of the BIVA probe may further benefit the intraoperative imaging in a clinical setting.

Assembly Transformation Jointly Driven by the LAP Enzyme and GSH Boosting Theranostic Capability for Effective Tumor Therapy

Developing intelligent and morphology-transformable nanomaterials that can spatiotemporally undergo stimulus-responsive size transformation holds great promise for improving the tumor delivery efficiency of drugs in vivo. Here, we report a smart size-transformable theranostic probe Ce6-Leu consisting of a leucine amino peptidase (LAP) and glutathione (GSH) dual-responsive moiety, an 1,2-aminothiol group, and a clinically used photosensitizer Ce6. This probe tends to self-assemble into uniform nanoparticles with an initial size of ∼80 nm in aqueous solution owing to the amphiphilic feature. Surprisingly, taking advantage of the biocompatible CBT-Cys condensation reaction, the large nanoprobes can be transformed into tiny nanoparticles (∼23 nm) under the joint action of LAP and GSH in a tumor microenvironment, endowing them with great tumor accumulation and deep tissue penetration. Concomitantly, this LAP/GSH-driven disassembly and size shrinkage of Ce6-Leu can also activate the fluorescence/magnetic resonance signals and the photodynamic effect for enhanced multimodal imaging-guided photodynamic therapy of human liver HepG2 tumors in vivo. More excitingly, the Mn²⁺-chelating probe (Ce6-Leu@Mn²⁺) was demonstrated to have the capability to catalyze endogenous H₂O₂ to persistently release O₂ at the hypoxic tumor site, as a consequence improving the oxygen supply to boost the radiotherapy effect. We thus believe that this LAP/GSH-driven size-transformable nanosystem would offer a novel advanced technology to improve the drug delivery efficiency for achieving precise tumor diagnosis and treatment.

Activatable molecular probes for fluorescence-guided surgery, endoscopy and tissue biopsy

The real-time, dynamic optical visualization of lesions and margins ensures not only complete resection of the malignant tissues but also better preservation of the vital organs/tissues during surgical procedures. Most imaging probes with an "always-on" signal encounter high background noise due to their non-specific accumulation in normal tissues. By contrast, activatable molecular probes only "turn on" their signals upon reaction with the targeted biomolecules that are overexpressed in malignant cells, offering high target-to-background ratios with high specificity and sensitivity. This review summarizes the recent progress of activatable molecular probes in surgical imaging and diagnosis. The design principle and mechanism of activatable molecular probes are discussed, followed by specific emphasis on applications ranging from fluorescence-guided surgery to endoscopy and tissue biopsy. Finally, potential challenges and perspectives in the field of activatable molecular probe-enabled surgical imaging are discussed.

Lipid Droplet-Specific Probe for Rapidly Locating Atherosclerotic Plaques and Intraoperative Imaging via In Situ Spraying

The ability to visualize the full extent of atherosclerotic plaques during surgery has major implications for therapeutic outcomes. Fluorescence imaging is a promising approach for atherosclerotic plaque inspection during surgery. However, a specific strategy for the intraoperative fluorescence imaging of atherosclerosis has not been established. This study presents an in situ spraying aerosol of a lipid droplet-specific probe to rapidly and precisely locate atherosclerotic plaques during surgery. Stable imaging of the plaque was achieved within 5 min by nebulizing the aqueous solution of the lipid droplet-specific probe (CN-PD) into 3 μm droplets and rapidly permeating it in situ. The visible fluorescence bioimaging of CN-PD can accurately delineate the plaque margins and size even with a diameter ≤0.5 mm, which are capable of being swiftly captured during the stable plaque imaging window (>2 h). This strategy combines the consideration of a specific probe design and an efficient in situ delivery, which results in weak interference from the background signals. Therefore, the plaque-to-normal tissue ratio (P/N) is sufficient to facilitate the surgical delineation of carotid atherosclerotic plaques. The originality of the intraoperative fluorescence imaging of the plaques via in situ delivery of the lipid droplet-specific probe holds promise for effective clinical application.

An activated excretion-retarded tumor imaging strategy towards metabolic organs

Intraoperative fluorescence-based tumor imaging plays a crucial role in performing the oncological safe tumor resection with the advantage of differentiating tumor from normal tissues. However, the application of these fluorescence contrast agents in renal cell carcinoma (RCC) and hepatocellular carcinoma (HCC) was dramatically hammered as a result of lacking active targeting and poor retention time in tumor, which limited the Signal to Noise Ratio (SNR) and narrowed the imaging window for complicated surgery. Herein, we reported an activated excretion-retarded tumor imaging (AERTI) strategy, which could be in situ activated with MMP-2 and self-assembled on the surface of tumor cells, thereby resulting in a promoted excretion-retarded effect with an extended tumor retention time and enhanced SNR. Briefly, the AERTI strategy could selectively recognize the Integrin α_vβ₃. Afterwards, the AERTI strategy would be activated and in situ assembled into nanofibrillar structure after specifically cleaved by MMP-2 upregulated in a variety of human tumors. We demonstrated that the AERTI strategy was successfully accumulated at the tumor sites in the 786-O and HepG2 xenograft models. More importantly, the modified modular design strategy obviously enhanced the SNR of AERTI strategy in the imaging of orthotopic RCC and HCC. Taken together, the results presented here undoubtedly confirmed the design and advantage of this AERTI strategy for the imaging of tumors in metabolic organs.

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Fluorescence-based tumor imaging plays a crucial role in performing the oncological safe tumor resection.

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Self-assembled peptide possesses the advantage of active targeting and long-term retention time in tumor.

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The activated excretion-retarded tumor imaging strategy extended the tumor retention time and enhanced SNR.

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Assembly-mediated peptide probe successfully achieved the accurate identification of tumor boundaries and detection of minimal tumors (<2 mm).

Supramolecular biomaterials for bio-imaging and imaging-guided therapy

Benefiting from their unique advantages, including reversibly switchable structures, good biocompatibility, facile functionalization, and sensitive response to biological stimuli, supramolecular biomaterials have been widely applied in biomedicine. In this review, the representative achievements and trends in the design of supramolecular biomaterials (mainly those derived from biomacromolecules) with specific macromolecules including peptides, deoxyribonucleic acid, and polysaccharides, as well as their applications in bio-imaging and imaging-guided therapy are summarized. This review will serve as an important summary and "go for" reference for explorations of the applications of supramolecular biomaterials in bio-imaging and image-guided therapy, and will promote the development of supramolecular chemistry as an emerging interdisciplinary research area.

Recent Progresses in NIR-I/II Fluorescence Imaging for Surgical Navigation

Cancer is still one of the main causes of morbidity and death rate around the world, although diagnostic and therapeutic technologies are used to advance human disease treatment. Currently, surgical resection of solid tumors is the most effective and a prior remedial measure to treat cancer. Although medical treatment, technology, and science have advanced significantly, it is challenging to completely treat this lethal disease. Near-infrared (NIR) fluorescence, including the first near-infrared region (NIR-I, 650-900 nm) and the second near-infrared region (NIR-II, 1,000-1,700 nm), plays an important role in image-guided cancer surgeries due to its inherent advantages, such as great tissue penetration, minimal tissue absorption and emission light scattering, and low autofluorescence. By virtue of its high precision in identifying tumor tissue margins, there are growing number of NIR fluorescence-guided surgeries for various living animal models as well as patients in clinical therapy. Herein, this review introduces the basic construction and operation principles of fluorescence molecular imaging technology, and the representative application of NIR-I/II image-guided surgery in biomedical research studies are summarized. Ultimately, we discuss the present challenges and future perspectives in the field of fluorescence imaging for surgical navigation and also put forward our opinions on how to improve the efficiency of the surgical treatment.

Smart Nanogatekeepers for Tumor Theranostics

Nanoparticulate drug delivery systems (nano-DDSs) are required to reliably arrive and persistently reside at the tumor site with minimal off-target side effects for clinical theranostics. However, due to the complicated environment and high interstitial pressure in tumor tissue, they can return to the bloodstream and cause secondary side effects in normal organs. Recently, a number of nanogatekeepers have been engineered via structure-transformable/stable strategies to overcome this undesirable dilemma. The emerging structure-transformable nanogatekeepers for tumor imaging and therapy are first overviewed here, particularly for nanogatekeepers undergoing structural transformation in tumor microenvironments, cell membranes, and organelles. Thereafter, intelligent structure-stable nanogatekeepers through reversible activation and artificial individualization receptors are overviewed. Finally, the ongoing challenges and prospects of nanogatekeepers for clinical translation are briefly discussed.