A NanoFlare-Based Strategy for In Situ Tumor Margin Demarcation and Neoadjuvant Gene/Photothermal Therapy

Nucleic Acid-Modified Nanoparticles for Cancer Therapeutic Applications

Nanomaterials including metal or metal oxide nanoparticles, carbonous nanomaterial (e.g., carbon dots) or metal-organic framework nanoparticles provide porous, catalytically active surfaces and functional interfaces for binding of ions or molecular agents. By the conjugation of nucleic acids to the nanoparticles, hybrid nanostructures revealing emerging multimodal catalytic/photocatalytic activities, high loading capacities, and effective targeted cell permeation efficacies are formed. The review article exemplifies the application of nucleic acid-modified nanoparticles conjugates for therapeutic treatment of cancer cells. Stimuli-responsive reconfiguration of nucleic acid strands and the specific recognition and catalytic function of oligonucleotides associated with porous, catalytic, and photocatalytic nanoparticles yield hybrid composites demonstrating cooperative synergistic properties for medical applications. The targeted chemodynamic, photodynamic, photothermal and chemotherapeutic treatment of cancer cells by the oligonucleotide/nanoparticle conjugates is addressed. In addition, the application of oligonucleotide/nanoparticle conjugates for gene therapy treatment of cancer cells is discussed.

A ZIF-8-based dual-modal smart responsive nanoplatform for overcoming radiotherapy resistance in advanced tumors

Radiation therapy is one of the core means of tumor treatment, playing an irreplaceable role in local control and radical treatment. However, radiotherapy resistance is one of the major challenges in current clinical practice. Tumor cells have a strong ability to repair DNA damage, which can effectively resist DNA double-strand breaks caused by X-rays, thus weakening the killing effect of radiotherapy. In addition, the complexity of the tumor microenvironment (TME) will further reduce the sensitivity of radiotherapy, leading to poor treatment results. With the rapid development of nanotechnology, the use of multi-modal combined therapy nanoplatforms has gradually become a new strategy to overcome radiotherapy resistance. These nanoplatforms achieve synergies by integrating multiple therapeutic approaches, such as radiation sensitization, photothermal therapy and chemotherapy. In this study, we utilized ZIF-8, a type of metal-organic framework, to simultaneously load ICG and rapamycin for X-ray sensitization and combined photothermal therapy. In this formulation, rapamycin enhances tumor cells' sensitivity to radiotherapy by inhibiting the mTOR signaling pathway, increasing DNA damage, regulating the cell cycle, and stimulating the STING pathway, which amplifies the tumor immune response. Meanwhile, ICG, as a photosensitizer, effectively converts light energy into heat, achieving tumor photothermal ablation. The modified drug-delivery system becomes a tumor-microenvironment-responsive smart carrier, increasing tumor cell uptake, prolonging retention at the tumor site, and achieving targeted drug delivery. It releases drugs in the specific tumor microenvironment, enhancing photothermal and radiotherapy sensitization effects. The results show that the smart dual-loaded nanoplatform effectively combines photothermal therapy and external-beam sensitization, reshapes the immunosuppressive tumor microenvironment and significantly inhibits tumor proliferation in the HepG2 subcutaneous xenograft model, demonstrating marked antitumor activity and good biosafety.

Protein corona potentiates the recovery of nanoparticle-induced disrupted tight junctions in endothelial cells

Nanoparticle interactions with biological systems are intricate processes influenced by various factors, among which the formation of protein corona plays a pivotal role. This research investigates a novel aspect of nanoprotein corona-cell interactions, focusing on the impact of the protein corona on the recovery of disrupted tight junctions in endothelial cells. We demonstrate that the protein corona formed on the surface of star-shaped nanoparticles induces the aggregates of ZO-1, which is quite important for the barriers' integrity. Our research emphasizes that the APOA1 pre-coating on the nanoparticles reduces the ZO-1 expression of endothelial cells offering a promising strategy for overcoming the bio barriers. These findings contribute to our understanding of the interplay between nanoparticles, protein corona, and endothelial cell junctions, offering insights for developing innovative therapeutic approaches targeting the blood-brain barrier integrity. Our study holds promise for the future of nanomedicine, nano drug delivery systems and development of strategies to mitigate potential adverse effects.

Smart Stimuli-Responsive Spherical Nucleic Acids: Cutting-Edge Platforms for Biosensing, Bioimaging, and Therapeutics

Spherical nucleic acids (SNAs) with exceptional colloidal stability, multiple modularity, and programmability are excellent candidates to address common molecular delivery-related issues. Based on this, the higher targeting accuracy and enhanced controllability of stimuli-responsive SNAs render them precise nanoplatforms with inestimable prospects for diverse biomedical applications. Therefore, tailored diagnosis and treatment with stimuli-responsive SNAs may be a robust strategy to break through the bottlenecks associated with traditional nanocarriers. Various stimuli-responsive SNAs are engineered through the incorporation of multifunctional modifications to meet biomedical demands with the development of nucleic acid functionalization. This review provides a comprehensive overview of prominent research in this area and recent advancements in the utilization of stimuli-responsive SNAs in biosensing, bioimaging, and therapeutics. For each aspect, SNA nanoplatforms that exhibit responsive behavior to both internal stimuli (including sequence, enzyme, redox reactions, and pH) and external stimuli (such as light and temperature) are highlighted. This review is expected to offer inspiration and guidance strategies for the rational design and development of stimuli-responsive SNAs in the field of biomedicine.

Spherical nucleic acids: emerging amplifiers for therapeutic nanoplatforms

Gene therapy is a revolutionary treatment approach in the 21st century, offering significant potential for disease prevention and treatment. However, the efficacy of gene delivery is often compromised by the inherent challenges of gene properties and vector-related defects. It is crucial to explore ways to enhance the curative effect of gene drugs and achieve safer, more widespread, and more efficient utilization, which represents a significant challenge in amplification gene therapy advancements. Spherical nucleic acids (SNAs), with their unique physicochemical properties, are considered an innovative solution for scalable gene therapy. This review aims to comprehensively explore the amplifying contributions of SNAs in gene therapy and emphasize the contribution of SNAs to the amplification effect of gene therapy from the aspects of structure, application, and recent clinical translation - an aspect that has been rarely reported or explored thus far. We begin by elucidating the fundamental characteristics and scaling-up properties of SNAs that distinguish them from traditional linear nucleic acids, followed by an analysis of combined therapy treatment strategies, theranostics, and clinical translation amplified by SNAs. We conclude by discussing the challenges of SNAs and provide a prospect on the amplification characteristics. This review seeks to update the current understanding of the use of SNAs in gene therapy amplification and promote further research into their clinical translation and amplification of gene therapy.

Zipper-Confined DNA Nanoframe for High-Efficient and High-Contrast Imaging of Heterogeneous Tumor Cell

Current study in the heterogeneity and physiological behavior of tumor cells is limited by the fluorescence in situ hybridization technology in terms of probe assembly efficiency, background suppression capability, and target compatibility. In a typically well-designed assay, hybridization probes are constructed in a confined nanostructure to achieve a rapid assembly for efficient signal response, while the excessively high local concentration between different probes inevitably leads to nonspecific background leakage. Inspired by the fabric zipper, we propose a novel confinement reaction pattern in a zipper-confined DNA nanoframe (ZCDN), where two kinds of hairpin probes are independently anchored respective tracks. The metastable states of the dual tracks can well avoid signal leakage caused by the nonspecific probe configuration change. Biomarker-mediated proximity ligation reduces the local distance of dual tracks, kinetically triggering an efficient allosteric chain reaction between the hairpin probes. This method circumvents nonspecific background leakage while maintaining a high efficiency in responding to targets. ZCDN is employed to track different cancer biomarkers located in both the cytoplasm and cytomembrane, of which the expression level and oligomerization behavior can provide crucial information regarding intratumoral heterogeneity. ZCDN exhibits high target response efficiency and strong background suppression capabilities and is compatible with various types of biological targets, thus providing a desirable tool for advanced molecular diagnostics.

Gene and Photothermal Combination Therapy: Principle, Materials, and Amplified Anticancer Intervention

Gene therapy (GT) and photothermal therapy (PTT) have emerged as promising alternatives to chemotherapy and radiotherapy for cancer treatment, offering noninvasiveness and reduced side effects. However, their efficacy as standalone treatments is limited. GT exhibits slow response rates, while PTT is confined to local tumor ablation. The convergence of GT and PTT, known as GT-PTT, facilitated by photothermal gene nanocarriers, has attracted considerable attention across various disciplines. In this integrated approach, GT reciprocates PTT by sensitizing cellular response to heat, while PTT benefits GT by improving gene translocation, unpacking, and expression. Consequently, this integration presents a unique opportunity for cancer therapy with rapid response and improved effectiveness. Extensive efforts over the past few years have been dedicated to the development of GT-PTT, resulting in notable achievements and rapid progress from the laboratory to potential clinical applications. This comprehensive review outlines recent advances in GT-PTT, including synergistic mechanisms, material systems, imaging-guided therapy, and anticancer applications. It also explores the challenges and future prospects in this nascent field. By presenting innovative ideas and insights into the implementation of GT-PTT for enhanced cancer therapy, this review aims to inspire further progress in this promising area of research.

GSH-activatable camptothecin prodrug-loaded gold nanostars coated with hyaluronic acid for targeted breast cancer therapy via multiple radiosensitization strategies

Breast cancer has overtaken lung cancer to rank as the top malignant tumor in terms of incidence. Herein, a gold nanostar (denoted as AuNS) is used for loading disulfide-coupled camptothecin-fluorophore prodrugs (denoted as CPT-SS-FL) to form a nanocomposite of AuNS@CPT-SS-FL (denoted as AS), which, in turn, is further encapsulated with hyaluronic acid (HA) to give the final nanoplatform of AuNS@CPT-SS-FL@HA (denoted as ASH). ASH effectively carries the prodrug and targets the CD44 receptor on the surface of tumor cells. The endogenously overexpressed glutathione (GSH) in tumor cells breaks the disulfide bond to activate the prodrug and release the radiosensitizer drug camptothecin (CPT) and the fluorescence imaging reagent rhodamine derivative as a fluorophore (FL). The released FL can track the precise release position of the radiosensitizer camptothecin in tumor cells in real time. The AuNS has strong X-ray absorption and deposition ability due to the high atomic coefficient of elemental Au (Z = 79). At the same time, the AuNS can alleviate the tumor microenvironment (TME) hypoxia through its mild photothermal therapy (PTT). Therefore, through the multiple radiosensitizing effects of GSH depletion, the high atomic coefficient of Au, and hypoxia alleviation, accompanied by the radiosensitizer camptothecin, the designed ASH nanoplatform can effectively induce strong immunogenic cell death (ICD) at the tumor site via radiosensitizing therapy combined with PTT. This work provides a new way of constructing a structurally compact and highly functionalized hierarchical system toward efficient breast cancer treatment through ameliorating the TME with multiple modalities.

Spherical nucleic acids-based nanoplatforms for tumor precision medicine and immunotherapy

Precise diagnosis and treatment of tumors currently still face considerable challenges due to the development of highly degreed heterogeneity in the dynamic evolution of tumors. With the rapid development of genomics, personalized diagnosis and treatment using specific genes may be a robust strategy to break through the bottleneck of traditional tumor treatment. Nevertheless, efficient in vivo gene delivery has been frequently hampered by the inherent defects of vectors and various biological barriers. Encouragingly, spherical nucleic acids (SNAs) with good modularity and programmability are excellent candidates capable of addressing traditional gene transfer-associated issues, which enables SNAs a precision nanoplatform with great potential for diverse biomedical applications. In this regard, there have been detailed reviews of SNA in drug delivery, gene regulation, and dermatology treatment. Still, to the best of our knowledge, there is no published systematic review summarizing the use of SNAs in oncology precision medicine and immunotherapy, which are considered new guidelines for oncology treatment. To this end, we summarized the notable advances in SNAs-based precision therapy and immunotherapy for tumors following a classification standard of different types of precise spatiotemporal control on active species by SNAs. Specifically, we focus on the structural diversity and programmability of SNAs. Finally, the challenges and possible solutions were discussed in the concluding remarks. This review will promote the rational design and development of SNAs for tumor-precise medicine and immunotherapy.

Recent advances in nanotechnology approaches for non-viral gene therapy

Gene therapy has shown great potential in the treatment of many diseases by downregulating the expression of certain genes. The development of gene vectors as a vehicle for gene therapy has greatly facilitated the widespread clinical application of nucleic acid materials (DNA, mRNA, siRNA, and miRNA). Currently, both viral and non-viral vectors are used as delivery systems of nucleic acid materials for gene therapy. However, viral vector-based gene therapy has several limitations, including immunogenicity and carcinogenesis caused by the exogenous viral vectors. To address these issues, non-viral nanocarrier-based gene therapy has been explored for superior performance with enhanced gene stability, high treatment efficiency, improved tumor-targeting, and better biocompatibility. In this review, we discuss various non-viral vector-mediated gene therapy approaches using multifunctional biodegradable or non-biodegradable nanocarriers, including polymer-based nanoparticles, lipid-based nanoparticles, carbon nanotubes, gold nanoparticles (AuNPs), quantum dots (QDs), silica nanoparticles, metal-based nanoparticles and two-dimensional nanocarriers. Various strategies to construct non-viral nanocarriers based on their delivery efficiency of targeted genes will be introduced. Subsequently, we discuss the cellular uptake pathways of non-viral nanocarriers. In addition, multifunctional gene therapy based on non-viral nanocarriers is summarized, in which the gene therapy can be combined with other treatments, such as photothermal therapy (PTT), photodynamic therapy (PDT), immunotherapy and chemotherapy. We also provide a comprehensive discussion of the biological toxicity and safety of non-viral vector-based gene therapy. Finally, the present limitations and challenges of non-viral nanocarriers for gene therapy in future clinical research are discussed, to promote wider clinical applications of non-viral vector-based gene therapy.

Modified Aerotaxy for the Plug-in Manufacture of Cell-Penetrating Fenton Nanoagents for Reinforcing Chemodynamic Cancer Therapy

The assemblies of anisotropic nanomaterials have attracted considerable interest in advanced tumor therapeutics because of the extended surfaces for loading of active molecules and the extraordinary responses to external stimuli for combinatorial therapies. These nanomaterials were usually constructed through templated or seed-mediated hydrothermal reactions, but the lack of uniformity in size and morphology, as well as the process complexities from multiple separation and purification steps, impede their practical use in cancer nanotherapy. Gas-phase epitaxy, also called aerotaxy (AT), has been introduced as an innovative method for the continuous assembly of anisotropic nanomaterials with a uniform distribution. This process does not require expensive crystal substrates and high vacuum conditions. Nevertheless, AT has been used limitedly to build high-aspect-ratio semiconductor nanomaterials. With these considerations, a modified AT was designed for the continuous in-flight assembly of the cell-penetrating Fenton nanoagents (Mn-Fe CaCO₃ (AT) and Mn-Fe SiO₂ (AT)) in a single-pass gas flow because cellular internalization activity is essential for cancer nanotherapeutics. The modified AT of Mn-Fe CaCO₃ and Mn-Fe SiO₂ to generate surface nanoroughness significantly enhanced the cellular internalization capability because of the preferential contact mode with the cancer cell membrane for Fenton reaction-induced apoptosis. In addition, it was even workable for doxorubicin (DOX)-resistant cancer cells after DOX loading on the nanoagents. After combining with immune-checkpoint blockers (antiprogrammed death-ligand 1 antibodies), the antitumor effect was improved further with no systemic toxicity as chemo-immuno-chemodynamic combination therapeutics despite the absence of targeting ligands and external stimuli.

Antimicrobial Peptide-Loaded Gelatinase-Responsive Photothermal Nanogel for the Treatment of Staphylococcus aureus-Infected Wounds

As the most common pathogen of community and nosocomial infection, the resistance of Staphylococcus aureus (S. aureus) to traditional antibiotics is still increasing with years. Although the potent antibacterial activity of antimicrobial peptides (AMPs) has been widely confirmed, the unpredictable cytotoxicity remains the biggest obstacle to their clinical application. The development of a targeted drug delivery system for S. aureus is a practical strategy to ameliorate the inherent limitations of AMPs. In this work, we constructed an AMP release nanogel (cypate-GNPs@Cy3-AMP, CGCA) of S. aureus infection microenvironment using gelatinase nanoparticles (GNPs) for toxicity control and bacterial clearance. Gelatinase present in the infected site degrades GNPs, thus releasing Cy3-AMP in situ to destroy bacterial cells. Cypate modified on the surface of GNPs supports CGCA to generate localized heat under near-infrared (NIR) laser irradiation, which together with AMPs could cause irreversible physical damage to bacteria. In addition, the encapsulation from GNPs not only effectively limited the toxicity of AMPs but also significantly promoted cell proliferation and migration in vitro. In the mouse infection model, CGCA also exhibited excellent effects of bacterial clearance and wound healing, providing a potential direction for the correct use of AMPs.

Biomimetic material degradation for synergistic enhanced therapy by regulating endogenous energy metabolism imaging under hypothermia

Inefficient tumour treatment approaches often cause fatal tumour metastases. Here, we report a biomimetic multifunctional nanoplatform explicitly engineered with a Co-based metal organic framework polydopamine heterostructure (MOF-PDA), anethole trithione (ADT), and a macrophage membrane. Co-MOF degradation in the tumour microenvironment releases Co²⁺, which results in the downregulation of HSP90 expression and the inhibition of cellular heat resistance, thereby improving the photothermal therapy effect of PDA. H₂S secretion after the enzymatic hydrolysis of ADT leads to high-concentration gas therapy. Moreover, ADT changes the balance between nicotinamide adenine dinucleotide/flavin adenine dinucleotide (NADH/FAD) during tumour glycolysis. ATP synthesis is limited by NADH consumption, which triggers a certain degree of tumour growth inhibition and results in starvation therapy. Potentiated 2D/3D autofluorescence imaging of NADH/FAD is also achieved in liquid nitrogen and employed to efficiently monitor tumour therapy. The developed biomimetic nanoplatform provides an approach to treat orthotopic tumours and inhibit metastasis.

Metal organic frameworks (MOF) coated with mammalian cell membranes have good biocompatibility. Here, the authors develop a cobalt based hydrogen sulphide producing MOF cloaked with a macrophage membrane and show that the subsequent system can reduce tumour growth in mice.

Enzymatically Controlled Nanoflares for Specific Molecular Recognition and Biosensing

In situ sensing of physiological and pathological species in cancer cells is of great importance to unravel their molecular and cellular processes. However, the biosensing with conventional probes is often limited by the undesired on-target off-tumor interference. Here, we report a novel strategy to design enzymatically controlled nanoflares for sensing and imaging molecular targets in tumor cells. The triggerable nanoflare was designed via rational engineering of structure-switching aptamers with the incorporation of an enzyme-activatable site and further conjugation on gold nanoparticles. The nanoflare sensors did not respond to target molecules in normal cells, but they could be catalytically activated by specific enzymes in cancer cells, thereby enabling cancer-specific sensing and imaging in vitro and in vivo with improved tumor specificity. Considering that diverse aptamers were selected, we expect that this strategy would facilitate the precise detection of a broad range of targets in tumors and may promote the development of smart probes for cancer diagnosis.

Gold nanostar‐based complexes applied for cancer theranostics

Cancer remains a major health problem that plagues human beings, calling widespread attention to develop novel theranostics to achieve sensitive diagnosis and efficient therapy. Multifunctional nanomedicine that can integrate diagnosis with treatment formulations has been emerging as a powerful strategy to overcome the current drawbacks in conventional clinical cancer treatments. Due to the good biocompatibility, easy surface modification, surface‐enhanced Raman spectroscopy (SERS)/computed tomography (CT)/photoacoustic (PA) imaging properties, and exceptional photothermal performance of gold nanostars (AuNSs), various AuNS‐based complexes or nanohybrids including metal compound/AuNSs, SiO2/AuNSs, polymer/AuNSs, and dendrimer/AuNSs, and so forth have been developed, holding great blueprint in cancer theranostics. Herein, we concisely review the recent progresses in the intriguing design of AuNS‐based nanoplatforms, and their applications in bioimaging, therapy and imaging‐guided cancer treatment, and clarify the possible future perspectives for the design of AuNS‐facilitated cancer theranostics.

Multitarget Reaction Programmable Automatic Diagnosis and Treatment Logic Device

Accurate diagnosis and precise and effective treatment are currently the two magic weapons for dealing with cancer. However, a single marker is often associated with multiple cellular events, which is not conducive to accurate diagnosis, and overly mild treatment methods often make the treatment effect unsatisfactory. In this paper, we construct a Au/Pd octopus nanoparticle-DNA nanomachine (Au/Pd ONP-DNA nanomachine) as a fully automatic diagnosis and treatment logic system. In this system, multiple DNA components are targeting detection units, Au/Pd ONPs act as carriers, and Au/Pd ONPs with an 808 nm laser is the treatment unit. In order to achieve the purpose of precise treatment, we will detect two secondary markers under the premise of detecting one major tumor marker. When all of the designated targets are detected (the logic system input is (1, 1, 1), and the output is (1, 1)), the 808 nm laser can be programmed to automatically radiate tumors and perform photothermal therapy and photodynamic therapy. In vivo and in vitro experiments show that this logic system not only can accurately identify tumor cells but also has considerable therapeutic effects.

Photocaged amplified FRET nanoflares: spatiotemporal controllable of mRNA-powered nanomachines for precise and sensitive microRNA imaging in live cells

There is considerable interest in creating a precise and sensitive strategy for in situ visualizing and profiling intracellular miRNA. Present here is a novel photocaged amplified FRET nanoflare (PAFN), which spatiotemporal controls of mRNA-powered nanomachine for precise and sensitive miRNA imaging in live cells. The PAFN could be activated remotely by light, be triggered by specific low-abundance miRNA and fueled by high-abundance mRNA. It offers high spatiotemporal control over the initial activity of nanomachine at desirable time and site, and a ‘one-to-more’ ratiometric signal amplification model. The PAFN, an unprecedented design, is quiescent during the delivery process. However, upon reaching the interest tumor site, it can be selectively activated by light, and then be triggered by specific miRNA, avoiding undesirable early activation and reducing nonspecific signals, allowing precise and sensitive detection of specific miRNA in live cells. This strategy may open new avenues for creating spatiotemporally controllable and endogenous molecule-powered nanomachine, facilitating application at biological and medical imaging.

A transformable gold nanocluster aggregate-based synergistic strategy for potentiated radiation/gene cancer therapy

Nano-radiosensitizers provide a powerful tool for cancer radiation therapy. However, their limited tumor retention/penetration and the inherent or adaptive radiation resistance of tumor cells hamper the clinical success of radiation therapy. Herein, we report a synergistic strategy for potentiated cancer radiation/gene therapy based on transformable gold nanocluster aggregates loaded with antisense oligonucleotide-targeting survivin mRNA (named AuNC-ASON). AuNC-ASON exhibited acidic pH-triggered structure splitting from a gold nanocluster aggregate (around 80 nm) to gold nanocluster (<2 nm), leading to the tumor microenvironment-responsive size transformation of the nano-radiosensitizer and activated release of the loaded antisense oligonucleotides to perform gene silencing. The in vitro experiments demonstrated that AuNC-ASON could amplify and improve the radio-sensitivity of tumor cells (the sensitization enhancement ratio was about 1.81) as a result of the synergistic effect of the transformable gold nanocluster radiosensitizer and survivin gene interference. Remarkably, the size transformation capability realized the high tumor retention/penetration and renal metabolism of AuNC-ASON in vivo and boosted the radio-susceptibility of cancer cells with the assistance of survivin gene interference, synergistically achieving potentiated tumor radiation/gene therapy. The proposed concept of transformable nano-radiosensitizer aggregate-based synergistic therapy can be utilized as a general strategy to guide the design of activatable multifunctional nanosystems for cancer theranostics.

Covalent Amide-Bonded Nanoflares for High-Fidelity Intracellular Sensing and Targeted Therapy: A Superstable Nanosystem Free of Nonspecific Interferences

A nanoflare, a conjugate of Au nanoparticles (NPs) and fluorescent nucleic acids, is believed to be a powerful nanoplatform for diagnosis and therapy. However, it highly suffers from the nonspecific detachment of nucleic acids from the AuNP surface because of the poor stability of Au-S linkages, thereby leading to the false-positive signal and serious side effects. To address these challenges, we report the use of covalent amide linkage and functional Au@graphene (AuG) NP to fabricate a covalent conjugate system of DNA and AuG NP, label-rcDNA-AuG. Covalent coating of abundant amino groups (-NH₂) onto the graphitic shell of AuG NP efficiently facilitates the coupling with carboxyl-labeled capture DNA sequences through simple, but strong, amide bonds. Importantly, such an amide-bonded nanoflare possesses excellent stability and anti-interference capability against the biological agents (nuclease, DNA, glutathione (GSH), etc.). By accurately monitoring the intracellular miR-21 levels, this covalent nanoflare is able to identify the positive cancer cells even in a mix of cancer and normal cells. Moreover, it allows for efficient photodynamic therapy of the targeted cancer cells with minimized side effects on normal cells. This work provides a facile approach to develop a superstable nanosystem showing promising potential in clinical diagnostics and therapy.

Enzyme-responsive turn-on nanoprobes for in situ fluorescence imaging and localized photothermal treatment of multidrug-resistant bacterial infections

Sensitive diagnosis and elimination of multidrug-resistant bacterial infections at an early stage remain paramount challenges. Herein, we present a gelatinase-responsive turn-on nanoprobe for in situ near-infrared (NIR) fluorescence imaging and localized photothermal treatment (PTT) of in vivo methicillin-resistant Staphylococcus aureus (MRSA) infections. The designed nanoprobe (named AuNS-Apt-Cy) is based on gold nanostars functionalized with MRSA-identifiable aptamer and gelatinase-responsive heptapeptide linker (CPLGVRG)-cypate complexes. The AuNS-Apt-Cy nanoprobe is non-fluorescent in aqueous environments due to the fluorescence resonance energy transfer between the gold nanostar core and cypate dye. We demonstrate that the AuNS-Apt-Cy nanoprobe can achieve MRSA targeting and accumulation as well as gelatinase (overexpressed in MRSA environments)-responsive turn-on NIR fluorescence due to the cleavage of the CPLGVRG linker and localized in vitro PTT via a mechanism involving bacterial cell wall and membrane disruption. In vivo experiments show that the AuNS-Apt-Cy nanoprobe can enable rapid (1 h post-administration) and in situ turn-on NIR fluorescence imaging with high sensitivity (105 colony-forming units) in diabetic wound and implanted bone plate mouse models. Remarkably, the AuNS-Apt-Cy nanoprobe can afford efficient localized PTT of diabetic wound and implanted bone plate-associated MRSA infections under the guidance of turn-on NIR fluorescence imaging, showing robust capability for early diagnosis and treatment of in vivo MRSA infections. In addition, the nanoprobe exhibits negligible damage to surrounding healthy tissues during PTT due to its targeted accumulation in the MRSA-infected site, guaranteeing its excellent in vivo biocompatibility and solving the main bottlenecks that hinder the clinical application of PTT-based antibacterial strategies.

Cyanine conjugates in cancer theranostics

Cyanine is a meritorious fluorogenic core for the construction of fluorescent probes and its phototherapeutic potential has been enthusiastically explored as well. Alternatively, the covalent conjugation of cyanine with other potent therapeutic agents not only boosts its therapeutic efficacy but also broadens its therapeutic modality. Herein, we summarize miscellaneous cyanine-therapeutic agent conjugates in cancer theranostics from literature published between 2014 and 2020. The application scenarios of such theranostic cyanine conjugates covered common cancer therapeutic modalities, including chemotherapy, phototherapy and targeted therapy. Besides, cyanine conjugates that serve as nanocarriers for drug delivery are introduced as well. In an additional section, we analyze the potential of these conjugates for clinical translation. Overall, this review is aimed to stimulate research interest in exploring unattempted therapeutic agents and novel conjugation strategies and hopefully, accelerate clinical translation in this field.

Design and enhanced gene silencing activity of spherical 2'-fluoroarabinose nucleic acids (FANA-SNAs)

Drug delivery vectors for nucleic acid therapeutics (NATs) face significant barriers for translation into the clinic. Spherical nucleic acids (SNAs) – nanoparticles with an exterior shell made up of DNA strands and a hydrophobic interior – have recently shown great potential as vehicles to improve the biodistribution and efficacy of NATs. To date, SNA design has not taken advantage of the powerful chemical modifications available to NATs. Here, we modify SNAs with 2′-deoxy-2′-fluoro-d-arabinonucleic acid (FANA-SNA), and show increased stability, enhanced gene silencing potency and unaided uptake (gymnosis) as compared to free FANA. By varying the spacer region between the nucleic acid strand and the attached hydrophobic polymer, we show that a cleavable DNA based spacer is essential for maximum activity. This design feature will be important when implementing functionalized nucleic acids into nanostructures for gene silencing. The modularity of the FANA-SNA was demonstrated by silencing two different targets. Transfection-free delivery was superior for the modified SNA compared to the free FANA oligonucleotide.

Optimizing FANA modified spherical nucleic acids (FANA-SNAs) for highly efficient delivery of nucleic acid therapeutics.

A Dendron-Based Fluorescence Turn-On Probe for Tumor Detection

Specifically amplifying the emission signals of optical probes in tumors is an effective way to improve the tumor-imaging sensitivity and contrast. In this paper, the first case of dendron-based fluorescence turn-on probes mediated by a Förster resonance energy transfer (FRET) mechanism is reported. Dendrons up to the fourth generation with a hydrophilic oligo(ethylene glycol) scaffold are synthesized by a solid-phase synthesis strategy, and show precise and defect-free chemical structures. To construct the fluorescence turn-on probe, one Cy5.5 molecule is conjugated to the focal of a G3 dendron through a robust linkage and eight Black Hole Quencher 3 (BHQ-3) molecules are conjugated to its periphery through a PEG chain bearing a reductively cleavable disulfide linkage. By in vitro and in vivo experiments, it is demonstrated that the fluorescence of the dendron-based probe can be activated effectively and rapidly in the reductive environments of tumor cells and tissues, and the probe thus exhibits amplified tumor signals and weak normal tissue signals. Compared with the reported nanoscale turn-on probes, the dendron-based probe has several significant advantages, such as well-defined chemical structure, precisely controllable fluorophore/quencher conjugation sites and ratio, desirable chemical stability, and reproducible pharmacokinetic and pharmacological profiles, and is very promising in tumor detection.

Ultrastable Near-Infrared Nonlinear Organic Chromophore Nanoparticles with Intramolecular Charge Transfer for Dually Photoinduced Tumor Ablation

Near-infrared (NIR) light-responsive nanoparticles (NPs) of organic photosensitizers (PS) hold great promise as phototherapeutic agents for precision photoinduced cancer therapy. However, highly photostable PS nanoparticles with extraordinary photoconversion capacities are urgently desired to fully realize potent phototherapy. Here, NIR nonlinear organic chromophore nanoparticles (NOC-NPs) are shown as single-component PS for dually cooperative phototherapy. Upon 785 nm irradiation, excited NOC-NPs pass through intrinsic intramolecular charge transfer (ICT) channel to generate both abundant singlet oxygen and local hyperthermia, affording synergistic photodynamic therapy (PDT) and photothermal therapy (PTT) for tumor ablation. Furthermore, NOC-NPs exhibit dramatic photostability, enhanced cellular uptake, effective cytoplasmic translocation, as well as preferable tumor accumulation, further ensuring favorable in vivo singlet oxygen generation and hyperthermia for photoinduced tumor ablation. Thus, NOC-NPs may represent novel high-performance PS for synergistic photoinduced cancer therapy, providing new insights into the development of potent PS for clinical translation.

Nucleic acid nanotechnology for cancer treatment

Cancer is one of the most prevalent potentially lethal diseases. With the increase in the number of investigations into the uses of nanotechnology, many nucleic acid (NA)-based nanostructures such as small interfering RNA, microRNA, aptamers, and immune adjuvant NA have been applied to treat cancer. Here, we discuss studies on the applications of NA in cancer treatment, recent research trends, and the limitations and prospects of specific NA-mediated gene therapy and immunotherapy for cancer treatment. The NA structures used for cancer therapy consist only of NA or hybrids comprising organic or inorganic substances integrated with functional NA. We also discuss delivery vehicles for therapeutic NA and anti-cancer agents, and recent trends in NA-based gene therapy and immunotherapy against cancer.

Advanced Nanotechnology Leading the Way to Multimodal Imaging-Guided Precision Surgical Therapy

Surgical resection is the primary and most effective treatment for most patients with solid tumors. However, patients suffer from postoperative recurrence and metastasis. In the past years, emerging nanotechnology has led the way to minimally invasive, precision and intelligent oncological surgery after the rapid development of minimally invasive surgical technology. Advanced nanotechnology in the construction of nanomaterials (NMs) for precision imaging-guided surgery (IGS) as well as surgery-assisted synergistic therapy is summarized, thereby unlocking the advantages of nanotechnology in multimodal IGS-assisted precision synergistic cancer therapy. First, mechanisms and principles of NMs to surgical targets are briefly introduced. Multimodal imaging based on molecular imaging technologies provides a practical method to achieve intraoperative visualization with high resolution and deep tissue penetration. Moreover, multifunctional NMs synergize surgery with adjuvant therapy (e.g., chemotherapy, immunotherapy, phototherapy) to eliminate residual lesions. Finally, key issues in the development of ideal theranostic NMs associated with surgical applications and challenges of clinical transformation are discussed to push forward further development of NMs for multimodal IGS-assisted precision synergistic cancer therapy.

Intracellular MicroRNA imaging using telomerase-catalyzed FRET ratioflares with signal amplification

Intracellular microRNA (miRNA) detection has attracted increasing attention, resulting in significant achievements. However, the development of an available tool that possesses a satisfactory signal-to-background ratio and high sensitivity for miRNA detection remains challenging. Herein, a class of telomerase-catalyzed FRET (fluorescence resonance energy transfer) ratioflares has been developed for the accurate sensing of low-abundance cancer-related miRNA both in a fluorescence assay and living cell imaging with signal amplification capacity. In this work, endogenous telomerase is led in a miRNA test system with signal amplification for the first time, wherein telomerase extends hexamer telomeric repeats (TTAGGG) using the 3' end of the capture probe as the primer. The synergetic work of telomerase and the catalyst strand (CS) makes the target miRNA circulate in the system, resulting in high sensitivity and an enhanced FRET signal an improved detection limit of 2.27 × 10-15 M. Meanwhile, telomerase-catalyzed FRET ratioflares allow the difference between cancer cells and normal cells to be increased reliably. Furthermore, low false positive signals resulting from chemical interference and minimized system fluctuations are achieved through ratiometric measurements.