Prodrug-Based Nanoreactors with Tumor-Specific In Situ Activation for Multisynergistic Cancer Therapy

Emerging glucose oxidase-delivering nanomedicines for enhanced tumor therapy

Abnormalities in glucose metabolism have been shown to characterize malignant tumors. Glucose depletion by glucose oxidase (GOD) has shown great potential in tumor therapy by causing tumor starvation. Since 2017, nanomedicines have been designed and utilized to deliver GOD for more precise and effective glucose modulation, which can overcome intrinsic limitations of different cancer therapeutic modalities by remodeling the tumor microenvironment to enhance antitumor therapy. To date, the topic of GOD-delivering nanomedicines for enhancing tumor therapy has not been comprehensively summarized. Herein, this review aims to provide an overview and discuss in detail recent advances in GOD delivery and directly involved starvation therapy strategies, GOD-sensitized various tumor therapy strategies, and GOD-mediated multimodal antitumor strategies. Finally, the challenges and outlooks for the future progress of the emerging tumor therapeutic nanomedicines are discussed. This review provides intuitive and specific insights to a broad audience in the fields of nanomedicines, biomaterials, and cancer therapy.

Advances in the Delivery, Activation and Therapeutics Applications of Bioorthogonal Prodrugs

Traditional prodrug strategies have been leveraged to overcome many inherent drawbacks of active native drugs in the drug research and development. However, endogenous stimuli such as specific microenvironment or enzymes are relied on to achieve the prodrug activation, resulting in unintended drug release and systemic toxicity. Alternatively, bioorthogonal cleavage reaction-enabled bioorthogonal prodrugs activation via exogenous triggers has emerged as a valuable approach, featuring spatiotemporally controlled drug release. Such bioorthogonal prodrug strategies would ensure targeted drug delivery and/or in situ generation, further circumventing systemic toxicity or premature elimination of active drugs. In recent years, metal-free bioorthogonal cleavage reactions with fast kinetics have boomed in the bioorthogonal prodrug design. Meanwhile, transition-metal-catalyzed and photocatalytic deprotection reactions have also been developed to trigger prodrug activation in biological systems. Besides traditional small molecule prodrugs, gasotransmitters have been successfully delivered to specific organelles or cells via bioorthogonal reactions, and nanosystems have been devised into bioorthogonal triggers as well. Herein, we present an overview of the latest advances in these bioorthogonally-uncaged prodrugs, focused on the delivery, activation and therapeutics applications.

Focused starvation of tumor cells using glucose oxidase: A comprehensive review

Starvation therapy targets the high metabolic demand of tumor cells. It primarily leans over the consumption of intracellular glucose and simultaneous blockade of alternative metabolic pathways. The strategy involves the use of glucose oxidase (GOx) for catalyzing the conversion of glucose into gluconic acid and hydrogen peroxide. Under these conditions, metabolic re-programming of tumor cells enables the utilization of substrates such as amino acids, fatty acids and lipids. This can be overcome by co-administration of chemo-, photo- and immuno-therapeutics together with glucose oxidase. Targeted delivery of glucose oxidase at tumor site can be enabled with the use of nanoformulations. In this review, we highlight that the outcomes of starvation therapy can be improved using rationally developed nano-formulations. It is possible to load synergistically acting bioactives in these formulations and deliver in site-specific manner and hence achieve the elimination of tumors cells with greater efficacy.

Opportunities for nanomaterials in enzyme therapy

In recent years, enzyme therapy strategies have rapidly evolved to catalyze essential biochemical reactions with therapeutic potential. These approaches hold particular promise in addressing rare genetic disorders, cancer treatment, neurodegenerative conditions, wound healing, inflammation management, and infectious disease control, among others. There are several primary reasons for the utilization of enzymes as therapeutics: their substrate specificity, their biological compatibility, and their ability to generate a high number of product molecules per enzyme unit. These features have encouraged their application in enzyme replacement therapy where the enzyme serves as the therapeutic agent to rectify abnormal metabolic and physiological processes, enzyme prodrug therapy where the enzyme initiates a clinical effect by activating prodrugs, and enzyme dynamic or starving therapy where the enzyme acts upon host substrate molecules. Currently, there are >20 commercialized products based on therapeutic enzymes, but approval rates are considerably lower than other biologicals. This has stimulated nanobiotechnology in the last years to develop nanoparticle-based solutions that integrate therapeutic enzymes. This approach aims to enhance stability, prevent rapid clearance, reduce immunogenicity, and even enable spatio-temporal activation of the therapeutic catalyst. This comprehensive review delves into emerging trends in the application of therapeutic enzymes, with a particular emphasis on the synergistic opportunities presented by incorporating enzymes into nanomaterials. Such integration holds the promise of enhancing existing therapies or even paving the way for innovative nanotherapeutic approaches.

Recent Progress in Anti-Tumor Nanodrugs Based on Tumor Microenvironment Redox Regulation

The growth state of tumor cells is strictly affected by the specific abnormal redox status of the tumor microenvironment (TME). Moreover, redox reactions at the biological level are also central and fundamental to essential energy metabolism reactions in tumors. Accordingly, anti-tumor nanodrugs targeting the disruption of this abnormal redox homeostasis have become one of the hot spots in the field of nanodrugs research due to the effectiveness of TME modulation and anti-tumor efficiency mediated by redox interference. This review discusses the latest research results of nanodrugs in anti-tumor therapy, which regulate the levels of oxidants or reductants in TME through a variety of therapeutic strategies, ultimately breaking the original "stable" redox state of the TME and promoting tumor cell death. With the gradual deepening of study on the redox state of TME and the vigorous development of nanomaterials, it is expected that more anti-tumor nano drugs based on tumor redox microenvironment regulation will be designed and even applied clinically.

Cascade strategy for glucose oxidase-based synergistic cancer therapy using nanomaterials

Nanomaterial-based cancer therapy faces significant limitations due to the complex nature of the tumor microenvironment (TME). Starvation therapy is an emerging therapeutic approach that targets tumor cell metabolism using glucose oxidase (GOx). Importantly, it can provide a material or environmental foundation for other diverse therapeutic methods by manipulating the properties of the TME, such as acidity, hydrogen peroxide (H2O2) levels, and hypoxia degree. In recent years, this cascade strategy has been extensively applied in nanoplatforms for ongoing synergetic therapy and still holds undeniable potential. However, only a few review articles comprehensively elucidate the rational designs of nanoplatforms for synergetic therapeutic regimens revolving around the conception of the cascade strategy. Therefore, this review focuses on innovative cascade strategies for GOx-based synergetic therapy from representative paradigms to state-of-the-art reports to provide an instructive, comprehensive, and insightful reference for readers. Thereafter, we discuss the remaining challenges and offer a critical perspective on the further advancement of GOx-facilitated cancer treatment toward clinical translation.

Tumor-targeted glycogen nanoparticles loaded with hemin and glucose oxidase to promote tumor synergistic therapy

Strategies which are used to address the low levels of intracellular hydrogen peroxide and the development of biocompatible catalysts still need to be fulfilled in tumor chemodynamic therapy. Therefore, a novel tumor-targeted glycogen-based nanoparticle system (GN/He/GOx/HA) was developed to co-deliver hemin (He) and GOx, which can self-supply glucose formed upon degradation of glycogen by α-glycosidase in the lysosome environment, in order to achieve synergistic antitumor therapy. Hyaluronic acid (HA) was selected as the outer shell to protect the activity of GOx, and to increase the uptake by tumor cells via CD44 receptor-mediated endocytosis. GN/He/GOx/HA NPs had a good stability in the blood circulation, but fast release of the therapeutic cargos upon intracellular uptake. Hemin had a cascade catalytic reaction with GOx. Furthermore, GN/He/GOx/HA NPs had the strongest cytotoxicity in Hela cells in a glucose concentration dependent manner. The NPs could efficiently produce reactive oxygen species in tumor cells, resulting in a decrease in the mitochondrial membrane potential and apoptosis of tumor cells. The in vivo results showed that the drug-loaded nanoparticles had good safety, biocompatibility, and efficacious antitumor effect. Therefore, the glycogen-based nanoparticle delivery system provides potential application for self-enhancing CDT, which can be used for effective antitumor therapy.

Inorganic nanoparticles as scaffolds for bioorthogonal catalysts

Bioorthogonal transition metal catalysts (TMCs) transform therapeutically inactive molecules (pro-drugs) into active drug compounds. Inorganic nanoscaffolds protect and solubilize catalysts while offering a flexible design space for decoration with targeting elements and stimuli-responsive activity. These "drug factories" can activate pro-drugs in situ, localizing treatment to the disease site and minimizing off-target effects. Inorganic nanoscaffolds provide structurally diverse scaffolds for encapsulating TMCs. This ability to define the catalyst environment can be employed to enhance the stability and selectivity of the TMC, providing access to enzyme-like bioorthogonal processes. The use of inorganic nanomaterials as scaffolds TMCs and the use of these bioorthogonal nanozymes in vitro and in vivo applications will be discussed in this review.

Synchronized delivery of dual-drugs for potentiating combination chemotherapy based on smart triple-responsive polymeric micelles

Here, we combined reversible addition-fragmentation chain transfer (RAFT) polymerization and amide coupling reaction to develop a novel drug-polymer conjugate using poly(AMA-co-IMMA)-b-poly(OEGMA) (termed as PAIPO) as nanocarriers. In order to enhance cellular uptake and obtain subsequent endo/lysosomal escape capacity, the dual-drugs-conjugated prodrug was then coupled with 2,3-dimethylmaleimide (DA) moieties and implanted with imidazolyl groups, respectively. Paclitaxel (PTX) was conjugated to PAIPO via 3,3'-dithiodipropionic acid (DPA) to construct a GSH-responsive moiety, while doxorubicin (DOX) was conjugated to PAIPO via 4-formyl benzoic acid to construct a pH-responsive moiety, which synergistically enabled a synchronized and precise drug delivery. The micelles self-assembled from DOX/PTX@PAIPO^DA showed an ideal average diameter (163.2-178.3 nm), contributing to passive targeting by the EPR effect. Moreover, a switch of the surface Zeta potential of micelles from steady negatively charged (- 9.74 ± 0.54 mV) at pH 7.4 to positively charged (+ 6.33 ± 1.25 mV) at pH 6.5, facilitated the long blood circulation and cellular endocytosis of micelles, respectively. More importantly, in vitro studies confirmed that ^DAM(DOX_n/PTX) exhibited a strong synergism against tumor cells, and under slightly acidic conditions (pH 6.5), the combination index (CI) values for ^DAM(DOX₁/PTX) on HeLa and Skov-3 cells were estimated to be 0.47 and 0.49 (previous to be 0.50 and 0.56 at pH 7.4), respectively. And in vivo results showed effective tumor accumulation potential, remarkable biosafety, and biocompatibility. Combined, such synchronized delivery approach based on multi-responsive micelles might potentiate the efficacy of combination chemotherapy in clinical cancer treatment.

Passing of Nanocarriers across the Histohematic Barriers: Current Approaches for Tumor Theranostics

Over the past several decades, nanocarriers have demonstrated diagnostic and therapeutic (i.e., theranostic) potencies in translational oncology, and some agents have been further translated into clinical trials. However, the practical application of nanoparticle-based medicine in living organisms is limited by physiological barriers (blood-tissue barriers), which significantly hampers the transport of nanoparticles from the blood into the tumor tissue. This review focuses on several approaches that facilitate the translocation of nanoparticles across blood-tissue barriers (BTBs) to efficiently accumulate in the tumor. To overcome the challenge of BTBs, several methods have been proposed, including the functionalization of particle surfaces with cell-penetrating peptides (e.g., TAT, SynB1, penetratin, R8, RGD, angiopep-2), which increases the passing of particles across tissue barriers. Another promising strategy could be based either on the application of various chemical agents (e.g., efflux pump inhibitors, disruptors of tight junctions, etc.) or physical methods (e.g., magnetic field, electroporation, photoacoustic cavitation, etc.), which have been shown to further increase the permeability of barriers.

Dual-prodrug cascade activation for chemo/chemodynamic mutually beneficial combination cancer therapy

The combination of chemodynamic therapy (CDT) and chemotherapy has shown promise for achieving improved cancer treatment outcomes. However, due to the lack of synergy rationale, a simple one-plus-one combination therapy remains suboptimal in overcoming the obstacles of each treatment approach. Herein, we report a nanoplatform consisting of a pH-sensitive ferrocene- and cinnamaldehyde-based polyprodrug and a hydrogen peroxide-responsive doxorubicin (DOX) prodrug. Under an acidic tumor environment, the cinnamaldehyde polyprodrug will be activated to release free cinnamaldehyde, which can increase the intracellular hydrogen peroxide level and enhance the Fenton reaction. Subsequently, due to the collapse of nanoparticle structures, the DOX prodrug will be released and activated under a hydrogen peroxide stimulus. Meanwhile, the quinone methide produced during DOX prodrug activation can consume glutathione, an important antioxidant, and thus in turn enhance the efficacy of CDT. This design of a nanoplatform with dual-prodrug cascade activation provides a promising mutually beneficial cooperation mode between chemotherapy and CDT for enhancing antitumor efficacy.

PROTAC Nanoplatform with Targeted Degradation of NAD(P)H:Quinone Oxidoreductase 1 to Enhance Reactive Oxygen Species-Mediated Apoptosis

Apoptosis mediated by reactive oxygen species (ROS) has emerged as a promising therapeutic strategy for tumors. However, the overexpression of NAD(P)H:quinone oxidoreductase 1 (NQO1) protein restricted ROS production through a negative feedback pathway in tumor cells, promoting tumor progression, and weakening the effect of drug therapy. Here, a PROTACs nanodrug delivery system (PN) was constructed to increase ROS generation by degrading the NQO1 protein. Specifically, a PROTAC (proteolytic targeting chimera) molecule DQ was designed and synthesized. Then DQ and withaferin A (WA, an inducer of ROS) were loaded into PNs. DQ degraded the overexpressed NQO1 protein in tumor cells through a protein ubiquitination degradation pathway, thereby weakening the antioxidant capacity of tumor cells. Meanwhile, the reduction of NQO1 could inhibit the negative feedback effect of ROS production, thus increasing ROS generation. It has been demonstrated that PNs can significantly increase ROS production and possess potent antitumor properties in vitro and in vivo. This nanoplatform may offer an alternative approach to treating tumors with NQO1 overexpression.

In Situ-Activated Phospholipid-Mimic Artemisinin Prodrug via Injectable Hydrogel Nano/Microsphere for Rheumatoid Arthritis Therapy

In situ-activated therapy is a decent option for localized diseases with improved efficacies and reduced side effects, which is heavily dependent on the local conversion or activation of bioinert components. In this work, we applied a phospholipid-mimic artemisinin prodrug (ARP) for preparing an injectable nano/microsphere to first realize an in situ-activated therapy of the typical systemically administrated artemisinin-based medicines for a localized rheumatoid arthritis (RA) lesion. ARP is simultaneously an alternative of phospholipids and an enzyme-independent activable prodrug, which can formulate "drug-in-drug" co-delivery liposomes with cargo of partner drugs (e.g., methotrexate). To further stabilize ARP/methotrexate "drug-in-drug" liposomes (MTX/ARPL) for a long-term intra-articular retention, a liposome-embedded hydrogel nano/microsphere (MTX/ARPL@MS) was prepared. After the local injection, the MTX/ARPL could be slowly released because of imine hydrolysis and targeted to RA synovial macrophages and fibroblasts simultaneously. ARP assembly is relatively stable before cellular internalization but disassembled ARP after lysosomal escape and converted into dihydroartemisinin rapidly to realize the effective in situ activation. Taken together, phospholipid-mimic ARP was applied for the firstly localized in situ-activated RA therapy of artemisinin-based drugs, which also provided a brand-new phospholipid-mimic strategy for other systemically administrated prodrugs to realize a remodeling therapeutic schedule for localized diseases.

Simultaneous self-supply of H2O2 and GSH-depleted intracellular oxidative stress for enhanced photodynamic/photothermal/chemodynamic therapy

Herein, we designed a new nanoplatform for combined PDT/PTT/CDT through simultaneously self-supplying H₂O₂ and depleting GSH using one single laser irradiation. The nanoplatform was capable of generating multiple reactive oxygen species (ROS), such as ¹O₂, O₂^-˙ and ˙OH, resulting in cell death. Moreover, the nanoplatform demonstrated low dark toxicity, high phototoxicity and better biosafety. In vivo animal experiments showed that the tumor growth was efficiently inhibited.

Glucose Metabolism Intervention-Facilitated Nanomedicine Therapy

Ordinarily, cancer cells possess features of abnormally increased nutrient intake and metabolic pathways. The disorder of glucose metabolism is the most important among them. Therefore, starvation therapy targeting glucose metabolism specifically, which results in metabolic disorders, restricted synthesis, and inhibition of tumor growth, has been developed for cancer therapy. However, issues such as inadequate targeting effectiveness and drug tolerance impede their clinical transformation. In recent years, nanomaterial-assisted starvation treatment has made significant progress in addressing these challenges, whether as a monotherapy or in combination with other medications. Herein, representative researches on the construction of nanosystems conducting starvation therapy are introduced. Elaborate designs and interactions between different treatment mechanisms are meticulously mentioned. Not only are traditional treatments based on glucose oxidase involved, but also newly sprung small molecule agents targeting glucose metabolism. The obstacles and potential for advancing these anticancer therapies were also highlighted in this review.

Nanoparticles: From synthesis to applications and beyond

In modern-day research, nanoparticles (size < 100nm) are an indispensable tool for various applications, especially in the field of biomedicine. Although enormous efforts have been made to understand the properties and specificities of nanoparticles, many questions are still not answered and the new ones arise. In this review we summarize current trends in the nanoparticle synthesis and characterization and interpret the stability of nanoparticles in various media from aqueous solutions to biological milieu important for the in vitro and in vivo studies. To get more detailed insight into nanoparticle charging properties and interactions of nanoparticles with interfaces the theoretical models are presented. Finally, the overview of nanoparticle applications is given and the future prospects are discussed.

Improving the Therapeutic Efficiency of Hypoxic-Activated Prodrugs by Enhancing Hypoxia in Solid Tumors

The low sensitivity of hypoxic regions in solid tumors to radiotherapy and chemotherapy remains a major obstacle to cancer treatment. By taking advantage of hypoxic-activated prodrugs, tirapazamine (TPZ), generating cytotoxic reductive products and the glucose oxidase (GO_x)-based glucose oxidation reaction, we designed a nanodrug-loading system that combined TPZ-induced chemotherapy with GO_x-mediated cancer-orchestrated starvation therapy and cancer oxidation therapy. In this work, we first prepared mesoporous silica (MSN) loaded with TPZ. Then, in order to prevent the leakage of TPZ in advance, the surface was coated with a layer of carMOF formed by Fe³⁺ and carbenicillin (car), and GO_x was adsorbed on the outermost layer to form the final nanosystem MSN-TPZ@carMOF-GO_x (MT@c-G). GO_x could effectively consume oxygen and catalyzed glucose into gluconic acid and hydrogen peroxide. First, the generated gluconic acid lowered the pH of tumor tissues, promoted the decomposition of carMOF, and released TPZ. Second, oxygen consumption could improve the degree of hypoxia in tumor tissues, so that enhanced the activity of TPZ. Furthermore, GO_x could generate cancer-orchestrated starvation/oxidation therapy. Therefore, our study provided a new strategy that TPZ combined with GO_x achieved starvation/oxidation/chemotherapy for enhancing anticancer effects in hypoxic regions.

Ion channel-targeting near-infrared photothermal switch with synergistic effect for specific cancer therapy

Despite significant achievement in chemotherapy, the off-target actions and low pharmaceutical selectivity of the therapeutic agents still limit their clinical efficacy. Herein, a multifunctional nanoplatform which integrates chemotherapy, chemodynamic therapy (CDT) and photoactivation of TRPV1 channels has been successfully established for specific cancer therapy. Polydopamine (PDA) coated hollow prussian blue nanocages (hPBNCs) are used as the photothermal switches and drug carriers for loading chemotherapeutic drug, doxorubicin (Dox). Conjugating with the TRPV1 antibodies enables the nanoplatform to bind specifically to TRPV1 channels on the plasma membrane of the TRPV1-positive cancer cells and then activate them by local heating upon NIR irradiation, leading to the over-influx of Ca²⁺. Critically, the laser irradiation can be carefully controlled to not only open the TRPV1 channels but also avoid burning of tumors by hyperthermia. Moreover, the exposed hPBNCs in the acidic tumor cells can decompose endogenous H₂O₂ into ˙OH by Fenton reaction to realize CDT, which further aggravates cancer cell apoptosis. Together with the chemotherapy caused by Dox, our nanoplatform displays an enhanced anticancer effect both in vitro and in vivo. Our work provides a powerful means for site-specific cancer synergetic therapy with high spatial and temporal resolution.

A Mitochondria-Localized Iridium(III)-Chlorin E6 Conjugate for Synergistic Sonodynamic and Two-Photon Photodynamic Therapy Against Melanoma

While melanoma in its early stages can be successfully treated, the prognosis strongly worsens with an increasing depth of the tumor. Capitalizing on this, there is an urgent need for...

Acid-responsive endosomolytic polymeric nanoparticles with amplification of intracellular oxidative stress for prodrug delivery and activation

Prodrug strategy especially in the field of chemotherapy of cancers possesses significant advantages reducing the side toxicity of anticancer drugs. However, high-efficiency delivery and in situ activation of prodrugs for tumor growth suppression are still a great challenge. Herein, we report rationally engineered pH-responsive endosomolytic polymeric micelles for the delivery of an oxidation-activable prodrug into the cytoplasm of cancer cells and amplification of intracellular oxidative stress for further prodrug activation. The prepared block copolymers consist of a poly(ethylene glycol) (PEG) block and a segment grafted by endosomolytic moieties and acetal linkage-connected cinnamaldehyde groups. The amphiphilic diblock copolymers can self-assemble to form micelles in water for loading the oxidation-activable phenylboronic pinacol ester-caged camptothecin prodrug (ProCPT). The obtained micelles can release free cinnamaldehyde under acidic conditions in tumor tissues and endo/lysosomes followed by efficient endosomal escape, which further induces enhancement of intracellular reactive oxygen species (ROS) to activate the prodrugs. Simultaneously, intracellular glutathione (GSH) can be reduced by quinone methide that was produced during prodrug activation. The ProCPT-loaded micelles can finally achieve efficient tumor accumulation and retention as well as effective tumor growth inhibition. More importantly, hematological and pathological analysis of toxicity reveals that the ProCPT-loaded micelles do not cause obvious toxic side effects toward important organs of mice. A positive immunomodulatory microenvironment in tumor tissue and serum can be detected after treatment with ProCPT-loaded micelles. Therefore, the endosomolytic ProCPT-loaded micelles exert synergistic therapeutic effects toward tumors through amplification of intracellular oxidative stress and activation of the prodrugs.

Recent advances in prodrug-based nanoparticle therapeutics

Extensive research into prodrug modification of active pharmaceutical ingredients and nanoparticle drug delivery systems has led to unprecedented levels of control over the pharmacological properties of drugs and resulted in the approval of many prodrug or nanoparticle-based therapies. In recent years, the combination of these two strategies into prodrug-based nanoparticle drug delivery systems (PNDDS) has been explored as a way to further advance nanomedicine and identify novel therapies for difficult-to-treat indications. Many of the PNDDS currently in the clinical development pipeline are expected to enter the market in the coming years, making the rapidly evolving field of PNDDS highly relevant to pharmaceutical scientists. This review paper is intended to introduce PNDDS to the novice reader while also updating those working in the field with a comprehensive summary of recent efforts. To that end, first, an overview of FDA-approved prodrugs is provided to familiarize the reader with their advantages over traditional small molecule drugs and to describe the chemistries that can be used to create them. Because this article is part of a themed issue on nanoparticles, only a brief introduction to nanoparticle-based drug delivery systems is provided summarizing their successful application and unfulfilled opportunities. Finally, the review's centerpiece is a detailed discussion of rationally designed PNDDS formulations in development that successfully leverage the strengths of prodrug and nanoparticle approaches to yield highly effective therapeutic options for the treatment of many diseases.

Nanoparticles and bioorthogonal chemistry joining forces for improved biomedical applications

Bioorthogonal chemistry comprises chemical reactions that can take place inside complex biological environments, providing outstanding tools for the investigation and elucidation of biological processes. Its use in combination with nanotechnology can lead to further developments in diverse areas of biomedicine, such as molecular bioimaging, targeted delivery, in situ drug activation, study of cell-nanomaterial interactions, biosensing, etc. Here, we summarise the recent efforts to bring together the unique properties of nanoparticles and the remarkable features of bioorthogonal reactions to create a toolbox of new or improved biomedical applications. We show how, by joining forces, bioorthogonal chemistry and nanotechnology can overcome some of the key current limitations in the field of nanomedicine, providing better, faster and more sensitive nanoparticle-based bioimaging and biosensing techniques, as well as therapeutic nanoplatforms with superior efficacy.