An orthogonally regulatable DNA nanodevice for spatiotemporally controlled biorecognition and tumor treatment

Two-step upconversion-driven PDT/CDT cooperative phototherapeutic platform based on surface magnetic field modulation

Photodynamic therapy utilizes photosensitizer to generate reactive oxygen species (ROS) under irradiation of light for anticancer. However, due to the strong absorption of visible light by tissues and organs, photodynamic therapy meets challenges in deep tissues. Herein, we propose an upconversion-driven photodynamic therapy combined with chemodynamic therapy based on UCNP@SiO2@Fe3O4@MC540. Upon the excitation of 980 nm laser, the visible emission of upconversion nanoparticles activates MC540 to produce ROS, which is enhanced by Fe3O4 through magnetic field modulation. Subsequently, Fe3O4 degrades under acidic conditions to produce ·OH via Fenton-reaction for chemodynamic therapy. The in vitro and in vivo experiments indicate that the two-step cooperative strategy exhibits significant anticancer efficacy. Besides, Finite Difference Time Domain (FDTD) simulation reveals that the enhancement stems from surface electric field and light absorption. It offers a deeper understanding of phototherapeutic process.

The nucleic acid reactions on the nanomaterials surface for biomedicine

Integrating nucleic acids (NAs) with nanomaterials has substantially advanced biomedical research, enabling critical applications in biosensing, drug delivery, therapeutics, and the synthesis of nanomaterials. At the core of these advances are the reactions of NAs on nanomaterial surfaces, encompassing conjugation (covalent and non-covalent), detachment (physical and chemical), and signal amplification (enzyme-mediated signal amplification, enzyme-free signal amplification, and DNA Walker). Here, we review the fundamental mechanisms and recent progress in nucleic acid reactions on nanomaterial surfaces, discuss emerging applications for diagnostics, nanomedicine, and gene therapy, and explore persistent challenges in the field. We offer a forward-looking perspective on how future developments could better control, optimize, and harness these reactions for transformative advances in nanomedicine and biomedical engineering.

Harnessing Nanomaterials for Enhanced DNA-Based Biosensing and Therapeutic Performance

The integration of nanomaterials with DNA-based systems has emerged as a transformative approach in biosensing and therapeutic applications. Unique features of DNA, like its programmability and specificity, complement the diverse functions of nanomaterials, leading to the creation of advanced systems for detecting biomarkers and delivering treatments. Here, we review the developments in DNA-nanomaterial conjugates, emphasizing their enhanced functionalities and potential across various biomedical applications. We first discuss the methodologies for synthesizing these conjugates, distinguishing between covalent and non-covalent interactions. We then categorize DNA-nanomaterials conjugates based on the properties of the DNA and nanomaterials involved, respectively. DNA probes are classified by their application into biosensing or therapeutic uses, and, several nanomaterials are highlighted by their recent progress in living biological. Finally, we discuss the current challenges and future prospects in this field, anticipating that significant progress in DNA-nanomaterial conjugates will greatly enhance precision medicine.

Development of NIR photocleavable nanoparticles with BDNF for vestibular neuron regeneration

Among nanoparticle platforms, light or photoresponsive nanoparticles have emerged as a promising drug delivery strategy with spatiotemporal control while minimizing off-target effects. The characteristic absorption spectrum of the photoresponsive moiety dictates the wavelength of light needed to activate bond cleavage. However, the low tissue penetration depth limit and short-wavelength ultraviolet (UV) cellular toxicity are considered disadvantageous. This study developed a vestibular ganglion neuron organoid as a model for vestibulopathy. UV and near-infrared (NIR) radiation targeted the inner ear and neural cells, followed by toxicity evaluation. A significantly smaller toxicity of NIR light was confirmed. The photocleavage release of brain-derived neurotrophic factor (BDNF) was used by applying NIR wavelength. The results indicate that polyethylene glycol octamethylene diamine derivative conjugated with leucomethylene blue with an ethanolamine linker nanoparticle can be effectively disassembled and release BDNF when using the 808 nm laser as a trigger. The findings of the cytotoxicity assay suggest that photocleavable nanoparticles (PCNs) and laser irradiation are safe and biocompatible for human-derived and neural progenitor types of cells. Phototriggered BDNF release by NIR laser supported the growth and differentiation of human neural progenitor cells in culture. In addition, the vestibulopathy organoid exhibited a significant regenerative effect. This study harnesses the full potential of NIR laser PCNs to treat vestibular neuropathies.

Full-color tuning in multi-layer core-shell nanoparticles from single-wavelength excitation

Lanthanide-based luminescent materials have shown great capabilities in addressing scientific problems encountered in diverse fields. However, achieving full-color switchable output under single-wavelength irradiation has remained a daunting challenge. Here we report a conceptual model to realize this aim by the temporal control of full upconversion evolution in a multi-layer core-shell nanostructure upon a single commercial 980-nm laser, instead of two or more excitation wavelengths as reported previously. We show that it is able to realize the red-to-green color change (from Er3+) under non-steady state excitation by constructing the cooperative modulation effect in the Er-Tm-Yb triple system, and single out the blue light (from Tm3+) by filtering out the short-decay emissions via a time-gating technique. The key role of Tm3+ in manipulating up-transition dynamics of Er3+ is further demonstrated. Our results present a deep insight into the photophysics of lanthanides, and help develop new generation of smart luminescent materials toward emerging photonic applications.

Dual-Mode Tumor Diagnosis and Guided Precise Photodynamic Therapy Based on MicroRNA Fluorescence Signal Amplification and Magnetic Resonance Imaging

Accurate and early tumor diagnosis is critical for effective cancer treatment, yet current diagnostic modalities often face limitations. Fluorescence imaging (FLI) and magnetic resonance imaging (MRI) both offer substantial potential for cancer diagnosis. However, FLI suffers from poor tissue penetration, while MRI lacks molecular specificity. To address these limitations, we proposed a dual-modal diagnostic strategy by combining FLI and MRI for precise photodynamic therapy (PDT) of tumors. A degradable tumor microenvironment (TME)-responsive nanoplatform, i.e., UCNPs-MB@MnO2-H1/H2 (UBMD), was developed. Intracellular overexpression of miRNA-21 triggers an in situ hybridization chain reaction between H1-TAMRA and H2-FAM, which significantly amplifies fluorescence resonance energy transfer and enables FLI of miRNA-21 in living cancer cells. On the other hand, UBMD activates MRI in the TME to remarkably amplify tumor MRI signals and to effectively compensate for the shortcoming of weak penetration of FLI in deep tissues. UBMD exhibits an NIR-activated PDT capability to enable tumor-specific in situ diagnostics and imaging. In vivo miRNA-21 FLI and MR imaging in living mice actively guide precise and efficient PDT of tumors.

Aptamer-based Immune Checkpoint Inhibition for Cancer Immunotherapy

Cancer has long been a significant threat to human life and health. The advent of immune checkpoint blockade strategies has reversed cancer-induced immune suppression, advanced the development of immunotherapy, and offered new hope in the fight against cancer. Aptamers, which possess the same specificity and affinity as antibodies, are advantageous due to their synthetic accessibility and ease of modification, providing novel insights for immune checkpoint research. In this review, we outline the key aptamers currently developed for immune checkpoints such as CTLA-4, PD-1, PD-L1 and Siglec-15. We explore their potential in therapeutic strategies, including functionalizing or engineering aptamers for covalent binding, valency control, and nanostructure assembly, as well as investigating molecular mechanisms such as glycosylated protein functions and cell-cell interactions. Finally, the future applications of aptamers in immunotherapy are discussed.

Programmable Intelligent DNA Nanoreactors (iDNRs) for in vivo Tumor Diagnosis and Therapy

With the rapid advancement of DNA technology, intelligent DNA nanoreactors (iDNRs) have emerged as sophisticated tools that harness the structural versatility and programmability of DNA. Due to their structural and functional programmability, iDNRs play an important and unique role in in vivo tumor diagnosis and therapy. This review provides an overview of the structural design methods for iDNRs based on advanced DNA technology, including enzymatic reaction-mediated and enzyme-free strategies. This review also focuses on how iDNRs achieve intelligence through functional design, as well as the applications of iDNRs for in vivo tumor diagnosis and therapy. In summary, this review summarizes current advances in iDNRs technology, discusses existing challenges, and proposes future directions for expanding their applications, which are expected to provide insights into the development of the field of in vivo tumor diagnostics and targeted therapies.

Tunable Tri‐Channel Orthogonal Full‐Color Luminescence in Nanostructure toward Anticounterfeiting and Information Security

Tunable orthogonal full‐color luminescence has emerged as a new class of smart luminescence phenomenon with wide applications ranging from photonics to biomedicine. However, the current research is focused on complex multilayer core‐shell nanostructures (e.g., 5–8 shell layers) with a single upconversion mode, greatly limiting their synthesis and practical application. Herein, this work proposes a simple core‐shell structure to integrate upconversion and downshifting dual‐mode luminescence based on Gd3+‐mediated interfacial energy transfer and Ce3+‐assisted cross relaxation. This design is able to suppress cross‐talk of multiple emissions and simplify the sample structure by removing the conventionally required intermediate isolation layer. Importantly, it further enables the arbitrarily controllable multicolor output at a single nanoparticle level by adopting the tri‐channel selective excitation wavelengths (980/808/254 nm), greatly expanding the conventional red‐green‐blue (RGB) color gamut. Moreover, the use of these nanoparticles promotes the information security level and the complexity of anti‐counterfeiting modes by adopting a pre‐set logic Morse information encryption and decryption strategy. These results provide effective guidance for the rational nanostructure design of novel orthogonal trichromatic emissive materials for a variety of frontier applications such as advanced anticounterfeiting and information security.

Dual electrochemical signal "signal-on-off" sensor based on CHA-Td-HCR and CRISPR-Cas12a for MUC1 detection

Mucin 1 (MUC1) is frequently overexpressed in various cancers and is essential for early cancer detection. Current methods to detect MUC1 are expensive, time-consuming, and require skilled personnel. Therefore, developing a simple, sensitive, highly selective MUC1 detection sensor is necessary. In this study, we proposed a novel "signal-on-off" strategy that, in the presence of MUC1, synergistically integrates catalytic hairpin assembly (CHA) with DNA tetrahedron (Td)-based nonlinear hybridization chain reaction (HCR) to enhance the immobilization of electrochemically active methylene blue (MB) on magnetic nanoparticles (MNP), marking the MB signal "on". Concurrently, the activation of CRISPR-Cas12a by isothermal amplification products triggers the cleavage of single-stranded DNA (ssDNA) at the electrode surface, resulting in a reduction of MgAl-LDH@Fc-AuFe-MIL-101 (containing ferrocene, Fc) on the electrode, presenting the "signal-off" state. Both MB and MgAl-LDH@Fc-AuFe-MIL-101 electrochemical signals were measured and analyzed. Assay parameters were optimized, and sensitivity, stability, and linear range were assessed. Across a concentration spectrum of MUC1 spanning from 10 fg/mL to 100 ng/mL, the MB and MgAl-LDH@Fc-AuFe-MIL-101 signals were calibrated with each other, demonstrating a "signal-on-off" dual electrochemical signaling pattern. This allows for the precise and quantitative detection of MUC1 in clinical samples, offering significant potential for medical diagnosis.

Aptamer-controlled stimuli-responsive drug release

Aptamers have been widely researched and applied in nanomedicine due to their programmable, activatable, and switchable properties. However, there are few reviews on aptamer-controlled stimuli-responsive drug delivery. This article highlights the mechanisms and advantages of aptamers in the construction of stimuli-responsive drug delivery systems. We summarize the assembly/reconfiguration mechanisms of aptamers in controlled release systems. The assembly and drug release strategies of drug delivery systems are illustrated. Specifically, we focus on the binding mechanisms to the target and the factors that induce/inhibit the binding to the stimuli, such as strand, pH, light, and temperature. The applications of aptamer-based stimuli-responsive drug release are elaborated. The challenges are discussed, and the future directions are proposed.

Titanium Carbide-Based Spatiotemporally Selectable-Activated Entropy-Driven DNA Nanoplatform for Amplified MicroRNA Imaging and Photothermal Therapy In Vivo

Engineering an elaborate nanotheranostic platform that can achieve spatiotemporally selective microRNA (miRNA) imaging and imaging-guided therapy in time is critical for precise cancer diagnosis and efficient treatment, yet remains a challenge. Herein, we present an on-site-activatable nanotheranostic platform (Ti3C2-NEDR) that engineers a photothermal-activated entropy-driven strand displacement reaction (NEDR) module on a photothermal conversion module (Ti3C2) for achieving spatiotemporally controlled miRNA-21 imaging in vivo and imaging-guided photothermal therapy only by varying the power of the near-infrared (NIR) laser. The upstream NIR photothermal conversion module, Ti3C2, can act not only as a DNA circuit carrier to deliver the NEDR module but also as a photothermal agent to activate the downstream NEDR module in low-power NIR laser irradiation. Once the NEDR module is activated by the NIR laser, the entropy-driven strand displacement reaction can be innated by intracellular miRNA-21 to generate an amplified fluorescence signal for the spatiotemporally selective imaging of miRNA-21 in vivo. Thereafter, the imaging-guided in vivo photothermal therapy can be achieved in time only by switching to the high-power NIR laser. It is envisioned that this strategy of NIR light-activated spatiotemporally selective miRNA imaging and imaging-guided on-demand therapy may expand the nanotheranostic platform for precise cancer diagnosis and personalized therapy in time, providing a remarkable prospect in biomedical diagnosis and therapy.

A Spatiotemporally Controlled Gene-Regulation Strategy for Combined Tumor Therapy Based on Upconversion Hybrid Nanosystem

The lack of precise spatiotemporal gene modulation and therapy impedes progress in medical applications. Herein, a 980 nm near-infrared (NIR) light-controlled nanoplatform, namely URMT, is developed, which can allow spatiotemporally controlled photodynamic therapy and trigger the enzyme-activated gene expression regulation in tumors. URMT is constructed by engineering an enzyme-activatable antisense oligonucleotide, which combined with an upconversion nanoparticle (UCNP)-based photodynamic nanosystem, followed by the surface functionalization of triphenylphosphine (TPP), a mitochondria-targeting ligand. URMT allows for the 980 nm NIR light-activated generation of reactive oxygen species, which can induce the translocation of a DNA repair enzyme (namely apurinic/apyrimidinic endonuclease 1, APE1) from the nucleus to mitochondria. APE1 can recognize the basic apurinic/apyrimidinic (AP) sites in DNA double-strands and perform cleavage, thereby releasing the functional single-strands for gene regulation. Overall, an augmented antitumor effect is observed due to NIR light-controlled mitochondrial damage and enzyme-activated gene regulation. Altogether, the approach reported in this study offers high spatiotemporal precision and shows the potential to achieve precise and specific gene regulation for targeted tumor treatment.

High-content tailoring strategy to improve the multifunctionality of functional nucleic acids

Functional nucleic acids (FNAs) have attracted increasing attention in recent years due to their diverse physiological functions. The understanding of their conformational recognition mechanisms has advanced through nucleic acid tailoring strategies and sequence optimization. With the development of the FNA tailoring techniques, they have become a methodological guide for nucleic acid repurposing. Therefore, it is necessary to systematize the relationship between FNA tailoring strategies and the development of nucleic acid multifunctionality. This review systematically categorizes eight types of FNA multifunctionality, and introduces the traditional FNA tailoring strategy from five aspects, including deletion, substitution, splitting, fusion and elongation. Based on the current state of FNA modification, a new generation of FNA tailoring strategy, called the high-content tailoring strategy, was unprecedentedly proposed to improve FNA multifunctionality. In addition, the multiple applications of rational tailoring-driven FNA performance enhancement in various fields were comprehensively summarized. The limitations and potential of FNA tailoring and repurposing in the future are also explored in this review. In summary, this review introduces a novel tailoring theory, systematically summarizes eight FNA performance enhancements, and provides a systematic overview of tailoring applications across all categories of FNAs. The high-content tailoring strategy is expected to expand the application scenarios of FNAs in biosensing, biomedicine and materials science, thus promoting the synergistic development of various fields.

DNA response element-based smart drug delivery systems for precise drug release

Smart drug delivery systems (DDSs) that respond to, interact with, or are actuated by biological signals or pathological abnormalities (e.g., the tumor microenvironment) for controllable drug release are appealing therapeutic platforms for cancer treatment. Owing to their inherent self-assembled nature, nucleic acids have emerged as programmable materials for the development of multifunctional structures. In response to external environmental stimuli, DNA response elements can serve as switches to trigger conformational changes in DNA structures. Their stimulus-responsive properties make them promising candidates for constructing smart DDSs, and advancements in DNA response element-based DDSs in the field of biomedicine have been made. This review summarizes different types of DNA response elements, including DNA aptamers, DNAzymes, disulfide bond-modified DNA, pH-responsive DNA motifs, and photocleavable DNA building blocks, and highlights the advancements in DNA response element-based smart DDSs for precise drug release. Finally, future challenges and perspectives in this field are discussed.

Biomimetic and multifunctional nanocomposites for precision fungi theranostics

Fungi infection is a serious threat to public health, but an effective antifungal strategy remains a challenge. Herein, a biomimetic nanocomposite with multifunctionalities, including fungi diagnosis, antifungal adhesion, precise fungi elimination, and cytokine sequestration, is constructed for battling Candida albicans (C. albicans) infection. By screening a range of cells, we find that the polarized macrophage cells have the strongest binding tendency toward C. albicans. Thus, their membranes were exfoliated to camouflage UCNPs and then decorated with photosensitizers (methylene blue, MB) and DNA sensing elements. The resulting nanocomposite can tightly bind to fungal surfaces, promote DNA recognition, and squeeze pro-inflammatory cytokines to relieve inflammation. Consequently, this nanocomposite can detect C. albicans with enhanced sensitivity and precisely eliminate fungal cells through photodynamic therapy with minimal phototoxicity because of its switchable fluorescence behavior. The developed nanocomposite with good biocompatibility achieves a satisfactory diagnostic and therapeutic effect in a C. albicans-infected mouse model, which offers a unique approach to fight fungi infection.

Construction of Smart DNA-Based Drug Delivery Systems for Cancer Therapy

Due to the disadvantages of poor targeting, slow action, and low effectiveness of current commonly used cancer treatments, including surgery, chemotherapy, and radiotherapy, researchers have turned to DNA as a biomaterial for constructing drug delivery nanocarriers. DNA is favored for its biocompatibility and programmability. In order to overcome the limitations associated with traditional drug delivery systems (DDSs), researchers have developed smart-responsive DNA DDSs that can control drug release in response to specific physical or chemical stimuli at targeted sites. In this review, a summary of multiple targeted ligand structures is provided, various shapes of stable DNA nanomaterials, and different stimuli-responsive drug release strategies in DNA DDSs. Specifically, targeted cell recognition, in vivo stable transport, and controlled drug release of smart DDSs are focused. Finally, the further development prospects and challenges of clinical application of DNA nanomaterials in the field of smart drug delivery are discussed. The objective of this review is to enhance researchers' comprehension regarding the potential application of DNA nanomaterials in precision drug delivery, with the aim of expediting the clinical implementation of intelligent DDSs.

Programmable melanoma-targeted radio-immunotherapy via fusogenic liposomes functionalized with multivariate-gated aptamer assemblies

Radio-immunotherapy exploits the immunostimulatory features of ionizing radiation (IR) to enhance antitumor effects and offers emerging opportunities for treating invasive tumor indications such as melanoma. However, insufficient dose deposition and immunosuppressive microenvironment (TME) of solid tumors limit its efficacy. Here we report a programmable sequential therapeutic strategy based on multifunctional fusogenic liposomes (Lip@AUR-ACP-aptPD-L1) to overcome the intrinsic radio-immunotherapeutic resistance of solid tumors. Specifically, fusogenic liposomes are loaded with gold-containing Auranofin (AUR) and inserted with multivariate-gated aptamer assemblies (ACP) and PD-L1 aptamers in the lipid membrane, potentiating melanoma-targeted AUR delivery while transferring ACP onto cell surface through selective membrane fusion. AUR amplifies IR-induced immunogenic death of melanoma cells to release antigens and damage-associated molecular patterns such as adenosine triphosphate (ATP) for triggering adaptive antitumor immunity. AUR-sensitized radiotherapy also upregulates matrix metalloproteinase-2 (MMP-2) expression that combined with released ATP to activate ACP through an "and" logic operation-like process (AND-gate), thus triggering the in-situ release of engineered cytosine-phosphate-guanine aptamer-based immunoadjuvants (eCpG) for stimulating dendritic cell-mediated T cell priming. Furthermore, AUR inhibits tumor-intrinsic vascular endothelial growth factor signaling to suppress infiltration of immunosuppressive cells for fostering an anti-tumorigenic TME. This study offers an approach for solid tumor treatment in the clinics.

Colorimetric aptasensor based on temporally controllable light-stimulated oxidase-mimicking fluorescein for the sensitive detection of exosomes in mild conditions

Analysis of exosomes provides important information for rapid and non-invasive screening of tumors. However, sensitive and convenient detection of exosomes remains technically challenging to date. Herein, a colorimetric aptasensor based on the light-stimulated oxidase-mimicking activity of FITC was constructed for detecting ovarian cancer (OC) exosomes. The aptasensor contained an EpCAM aptamer to capture OC exosomes. Cholesterol and fluorescein (FITC) were used to modify either end of the DNA (DNA anchor). The DNA anchor could combine with exosomes through a hydrophobic reaction between cholesterol and the lipid membrane. FITC oxidized 3,3',5,5'-tetramethylbenzidine (TMB) under a 365 nm LED light source in a temporally controllable manner under mild conditions, causing the solution to change from colorless to blue, and the corresponding UV-vis absorbance increased. Based on this principle, the exosomes were qualitatively analyzed by observing the color change with the naked eye. In parallel, the exosome concentration was also detected using UV-vis spectrophotometry. The linear range was from 2 × 105 to 100 × 105 particles per mL with a limit of detection of 1.77 × 105 particles per mL. The developed aptasensor also exhibited favorable selectivity and could discriminate the exosomes from OC cells and normal cells. Besides, the receiver operating characteristic (ROC) curve demonstrates that it is possible to distinguish between patients with OC and healthy donors (HDs) using exosomes as the biomarker. Our technology may expand the applications of DNA-based detection method-enabled OC diagnostic tools.

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.

Self-Assembled DNA Nanospheres Driven by Carbon Dots for MicroRNAs Imaging in Tumor via Logic Circuit

DNA nanostructures with diverse biological functions have made significant advancements in biomedical applications. However, a universal strategy for the efficient production of DNA nanostructures is still lacking. In this work, a facile and mild method is presented for self-assembling polyethylenimine-modified carbon dots (PEI-CDs) and DNA into nanospheres called CANs at room temperature. This makes CANs universally applicable to multiple biological applications involving various types of DNA. Due to the ultra-small size and strong cationic charge of PEI-CDs, CANs exhibit a dense structure with high loading capacity for encapsulated DNA while providing excellent stability by protecting DNA from enzymatic hydrolysis. Additionally, Mg2+ is incorporated into CANs to form Mg@CANs which enriches the performance of CANs and enables subsequent biological imaging applications by providing exogenous Mg2+. Especially, a DNAzyme logic gate system that contains AND and OR Mg@CANs is constructed and successfully delivered to tumor cells in vitro and in vivo. They can be specifically activated by endogenic human apurinic/apyrimidinic endonuclease 1 and recognize the expression levels of miRNA-21 and miRNA-155 at tumor sites by logic biocomputing. A versatile pattern for delivery of diverse DNA and flexible logic circuits for multiple miRNAs imaging are developed.

Light Responsive DNA Nanomaterials and Their Biomedical Applications

DNA nanomaterials have been widely employed for various biomedical applications. With rapid development of chemical modification of nucleic acid, serials of stimuli-responsive elements are included in the multifunctional DNA nanomaterials. In this review, we summarize the recent advances in light responsive DNA nanomaterials based on photocleavage/photodecage, photoisomerization, and photocrosslinking for efficient bioimaging (including imaging of small molecule, microRNA, and protein) and drug delivery (including delivery of small molecule, nucleic acid, and gene editing system). We also discuss the remaining challenges and future perspectives of the light responsive DNA nanomaterials in biomedical applications.

A DNA/Upconversion Nanoparticle Complex Enables Controlled Co-Delivery of CRISPR-Cas9 and Photodynamic Agents for Synergistic Cancer Therapy

Photodynamic therapy (PDT) depends on the light-irradiated exciting of photosensitizer (PS) to generate reactive oxygen species (ROS), which faces challenges and limitations in hypoxia and antioxidant response of cancer cells, and limited tissue-penetration of light. Herein, a multifunctional DNA/upconversion nanoparticles (UCNPs) complex is developed which enables controlled co-delivery of CRISPR-Cas9, hemin, and protoporphyrin (PP) for synergistic PDT. An ultralong single-stranded DNA (ssDNA) is prepared via rolling circle amplification (RCA), which contains recognition sequences of single guide RNA (sgRNA) for loading Cas9 ribonucleoprotein (RNP), G-quadruplex sequences for loading hemin and PP, and linker sequences for combining UCNP. Cas9 RNP cleaves the antioxidant regulator nuclear factor E2-related factor 2 (Nrf2), improving the sensitivity of cancer cells to ROS, and enhancing the synergistic PDT effect. The G-quadruplex/hemin DNAzyme mimicks horseradish peroxidase (HRP) to catalyze the endogenous H2O2 to O2, overcoming hypoxia condition in tumors. The introduced UCNP converts NIR irradiation with deep tissue penetration to light with shorter wavelength, exciting PP to transform the abundant O2 to 1O2. The integration of gene editing and PDT allows substantial accumulation of 1O2 in cancer cells for enhanced cell apoptosis, and this synergistic PDT has shown remarkable therapeutic efficacy in a breast cancer mouse model.

Spatiotemporal control of photochromic upconversion through interfacial energy transfer

Dynamic control of multi-photon upconversion with rich and tunable emission colors is stimulating extensive interest in both fundamental research and frontier applications of lanthanide based materials. However, manipulating photochromic upconversion towards color-switchable emissions of a single lanthanide emitter is still challenging. Here, we report a conceptual model to realize the spatiotemporal control of upconversion dynamics and photochromic evolution of Er3+ through interfacial energy transfer (IET) in a core-shell nanostructure. The design of Yb sublattice sensitization interlayer, instead of regular Yb3+ doping, is able to raise the absorption capability of excitation energy and enhance the upconversion. We find that a nanoscale spatial manipulation of interfacial interactions between Er and Yb sublattices can further contribute to upconversion. Moreover, the red/green color-switchable upconversion of Er3+ is achieved through using the temporal modulation ways of non-steady-state excitation and time-gating technique. Our results allow for versatile designs and dynamic management of emission colors from luminescent materials and provide more chances for their frontier photonic applications such as optical anti-counterfeiting and speed monitoring.

Photoactivation Inducing Multifunctional Coupling of Fluorophore for Efficient Tumor Therapy In Situ

Photoactivatable molecules, with high-precision spatialtemporal control, have largely promoted bioimaging and phototherapy applications of fluorescent dyes. Here, the first photoactivatable sensor (BI) is described that can be triggered by broad excitation light (405-660 nm), which further undergoes intersystem crossing and H-atom transfer processes to forming superoxide anion radicals (O2 -• ) and carbon radicals. Particularly, the photoinduced gain of carbon-centered radicals (BI•) allows for radical-radical coupling to afford the combined crosslink product (BI─BI), which would be oxidized in the presence of O2 -• to produce an extended conjugate system with near infrared emission (820 nm). Besides, the photochemically generated product (Cy─BI) possesses ultra-high photothermal conversion efficiency up to 90.9%, which optimized phototherapy potential. What's more, Western Blot assay reveals that both BI and the photoproduct Cy─BI can efficiently inhibit the expression of CHK1, and the irradiation of BI and Cy─BI further induces apoptosis and ultimately enhances the phototherapeutic effects. Thus, the combination of cell cycle block inducing apoptosis, photodynamic therapy and photothermal therapy treatments significantly suppress solid tumor in vivo antitumor efficacy explorations. This is a novel finding in developing photoactivatable molecules, as well as the broad applicability of photoimaging and phototherapy in tumor-related areas.

Spatiotemporally Programmed Disassembly of Multifunctional Integrated DNAzyme Nanoplatfrom for Amplified Intracellular MicroRNA Imaging

The sensing performance of DNAzymes in live cells is tremendously hampered by the inefficient and inhomogeneous delivery of DNAzyme probes and their incontrollable off-site activation, originating from their susceptibility to nuclease digestion. This requires the development of a more compact and robust DNAzyme-delivering system with site-specific DNAzyme activation property. Herein, a highly compact and robust Zn@DDz nanoplatform is constructed by integrating the unimolecular microRNA-responsive DNA-cleaving DNAzyme (DDz) probe with the requisite DNAzyme Zn2+ -ion cofactors, and the amplified intracellular imaging of microRNA via the spatiotemporally programmed disassembly of Zn@DDz nanoparticles is achieved. The multifunctional Zn@DDz nanoplatform is simply composed of a structurally blocked self-hydrolysis DDz probe and the inorganic Zn2+ -ion bridge, with high loading capacity, and can effectively deliver the initially catalytic inert DDz probe and Zn2+ into living cells with enhanced stabilities. Upon their entry into the acidic microenvironment of living cells, the self-sufficient Zn@DDz nanoparticle is disassembled to release DDz probe and simultaneously supply Zn2+ -ion cofactors. Then, endogenous microRNA-21 catalyzes the reconfiguration and activation of DDz for generating the amplified readout signal with multiply guaranteed imaging performance. Thus, this work paves an effective way for promoting DNAzyme-based biosensing systems in living cells, and shows great promise in clinical diagnosis.

Mitochondria-Targeting Upconversion Nanoparticles@MOF for Multiple-Enhanced Photodynamic Therapy in Hypoxic Tumor

The effect of photodynamic therapy (PDT) is severely limited by tumor hypoxia and the short half-life of reactive oxygen species (ROS). Herein, we constructed a near-infrared (NIR) light-regulated PDT nanoplatform (TPP-UCNPs@MOF-Pt) consisting of an upconversion nanoparticle (UCNP) core and porphyrin-based metal-organic framework (MOF) shell with platinum nanoparticles (PtNPs) and a mitochondria-targeting triphenylphosphine (TPP) group on the surface. TPP-UCNPs@MOF-Pt could effectively relieve the tumor hypoxia by converting intracellular H₂O₂ to oxygen (O₂) and elevated the ROS level to enhance PDT efficacy under NIR light irradiation. In addition, the mitochondria-targeting TPP-UCNPs@MOF-Pt was localized on the mitochondria, leading to severe depolarization of the mitochondrial membrane and activation of the apoptotic pathway, further amplifying the therapeutic efficacy. In vitro and in vivo experiments demonstrated that the greatly enhanced photodynamic therapeutic efficacy of TPP-UCNPs@MOF-Pt was achieved by combining relief of tumor hypoxia with mitochondrial targeting and NIR activation. This study provides a promising strategy for construction of an MOF-based multifunctional nanoplatform to address the current limitations of PDT treatment for hypoxic tumors.

Phosphorothioated DNA Engineered Liposomes as a General Platform for Stimuli-Responsive Cell-Specific Intracellular Delivery and Genome Editing

Intracellular protein delivery is highly desirable for protein drug-based cell therapy. Established technologies suffer from poor cell-specific cytosolic protein delivery, which hampers the targeting therapy of specific cell populations. A fusogenic liposome system enables cytosolic delivery, but its ability of cell-specific and controllable delivery is quite limited. Inspired by the kinetics of viral fusion, we designed a phosphorothioated DNA coatings-modified fusogenic liposome to mimic the function of viral hemagglutinin. The macromolecular fusion machine docks cargo-loaded liposomes at the membrane of target cells, triggers membrane fusion upon pH or UV light stimuli, and facilitates cytosolic protein delivery. Our results showed efficient cell-targeted delivery of proteins of various sizes and charges, indicating the phosphorothioated DNA plug-in unit on liposomes could be a general strategy for spatial-temporally controllable protein delivery both in vitro and in vivo.

Photoallosteric Polymersomes toward On-Demand Drug Delivery and Multimodal Cancer Immunotherapy

Allosteric transitions can modulate the self-assembly and biological function of proteins. It remains, however, tremendously challenging to design synthetic allosteric polymeric assemblies with spatiotemporally switchable hierarchical structures and functionalities. Here, a photoallosteric polymersome is constructed that undergoes a rapid conformational transition from β-sheet to α-helix upon exposure to near-infrared light irradiation. In addition to improving nanoparticle cell penetration and lysosome escape, photoinduced allosteric behavior reconstructs the vesicular membrane structure, which stimulates the release of hydrophilic cytolytic peptide melittin and hydrophobic kinase inhibitor sorafenib. Combining on-demand delivery of multiple therapeutics with phototherapy results in apoptosis and immunogenic death of tumor cells, remold the immune microenvironment and achieve an excellent synergistic anticancer efficacy in vivo without tumor recurrence and metastasis. Such a light-modulated allosteric transition in non-photosensitive polymers provides new insight into the development of smart nanomaterials for biosensing and drug delivery applications.

Bidirectional near-infrared regulation of motor behavior using orthogonal emissive upconversion nanoparticles

Bidirectional optogenetic manipulation enables specific neural function dissection and animal behaviour regulation with high spatial-temporal resolution. It relies on the respective activation of two or more visible-light responsive optogenetic sensors, which inevitably induce signal crosstalk due to their spectral overlap, low photoactivation efficiency and potentially high biotoxicity. Herein, a strategy that combines dual-NIR-excited orthogonal emissive upconversion nanoparticles (OUCNPs) with a single dual-colour sensor, BiPOLES, is demonstrated to achieve bidirectional, crosstalk-free NIR manipulation of motor behaviour in vivo. Core@shell-structured OUCNPs with Tm³⁺ and Er³⁺ dopants in isolated layers exhibit orthogonal blue and red emissions in response to excitation at 808 and 980 nm, respectively. The OUCNPs subsequently activate BiPOLES-expressing excitatory cholinergic motor neurons in C. elegans, leading to significant inhibition and excitation of motor neurons and body bends, respectively. Importantly, these OUCNPs exhibit negligible toxicity toward neural development, motor function and reproduction. Such an OUCNP-BiPOLES system not only greatly facilitates independent, bidirectional NIR activation of a specific neuronal population and functional dissection, but also greatly simplifies the bidirectional NIR optogenetics toolset, thus endowing it with great potential for flexible upconversion optogenetic manipulation.

Engineered photoresponsive biohybrids for tumor therapy

Engineered biohybrids have recently emerged as innovative biomimetic platforms for cancer therapeutic applications. Particularly, engineered photoresponsive biohybrids hold tremendous potential against tumors due to their intriguing biomimetic properties, photoresponsive ability, and enhanced biotherapeutic functions. In this review, the design principles of engineered photoresponsive biohybrids and their latest progresses for tumor therapy are summarized. Representative engineered photoresponsive biohybrids are highlighted including biomolecules-associated, cell membrane-based, eukaryotic cell-based, bacteria-based, and algae-based photoresponsive biohybrids. Representative tumor therapeutic modalities of the engineered photoresponsive biohybrids are presented, including photothermal therapy, photodynamic therapy, synergistic therapy, and tumor therapy combined with tissue regeneration. Moreover, the challenges and future perspectives of these photoresponsive biohybrids for clinical practice are discussed.

An orthogonally activatable CRISPR-Cas13d nanoprodrug to reverse chemoresistance for enhanced chemo-photodynamic therapy

Orthogonal therapy that combines CRISPR-based gene editing and prodrug-based chemotherapy is a promising approach to combat multidrug-resistant cancer. However, its potency to precisely regulate different therapeutic modalities in vivo is limited due to the lack of an integrated platform with high spatiotemporal resolution. Taking advantage of CRISPR technology, a Pt(iv)-based prodrug and orthogonal emissive upconversion nanoparticles (UCNPs), we herein rationally designed the first logic-gated CRISPR-Cas13d-based nanoprodrug for orthogonal photomodulation of gene editing and prodrug release for enhanced cancer therapy. The nanoprodrug (URL) was constructed by encapsulating a green light-activatable Pt(iv) prodrug and UV light-activatable Cas13d gene editing tool into UCNPs. We demonstrated that URL maintained excellent orthogonal emission behaviors under 808 and 980 nm excitations, allowing wavelength-selective photoactivation of Cas13d and the prodrug for downregulation of the resistance-related gene and induction of chemo-photodynamic therapy, respectively. Moreover, the photomodulation superiority of URL for overcoming drug resistance was highlighted by integrating it with a Boolean logic gate for programmable modulation of multiple cell behaviors. Importantly, in vivo studies demonstrated that URL can promote Pt(iv) prodrug activation and ROS generation and massively induce on-target drug accumulation by Cas13d-mediated drug resistance attenuation, delivering an ultimate chemo-photodynamic therapeutic performance in efficiently eradicating primary tumors and preventing further liver metastasis. Collectively, our results suggest that URL expands the Cas13d-based genome editing toolbox into prodrug nanomedicine and accelerates the discovery of new orthogonal therapeutic approaches.

Tumor-specific activated nano-domino-CRISPR to amplify intrinsic oxidative and activate endogenous apoptosis for spatiotemporally specific therapy

As a non-invasive modality with unique spatiotemporal selectivity, photodynamic therapy (PDT) is emerging as a candidate in cancer treatment. Nevertheless, intrinsic anti-oxidative stress factors represented by the up-regulated B cell lymphoma/leukemia-2 (Bcl-2) and the attenuated-PDT activity along the light path are still the major concerns, therefore exploring the PDT-based synergistic and augmented strategies is challenging but imperative. Here, a tumor-specific activated nano-domino-CRISPR (TAN) is fabricated and coloaded with chlorins e6 (Ce6) and CRISPR/Cas9 plasmid targeting Bcl-2 gene to amplify intrinsic oxidative and activate endogenous apoptosis for spatiotemporally specific therapy. Inert TAN acting as the first domino is activated in enzyme-abundant intracellular environment to strip the shell. The activated TAN pushes the subsequent dominos, encompassing orderly efficient lysosomal escape, gene delivery, precise disruption of Bcl-2 protein and PDT effect induced by the shell containing Ce6 with light to trigger further domino effects. For tumor cells located superficial sites, down-regulated Bcl-2 reduces cellular GSH content and potentiates oxidative stress of PDT. Cells located deep sites are triggered endogenous apoptosis by disruption of Bcl-2. The high anti-tumor efficacy of TAN is demonstrated both in vitro and in vivo. Overall, our work offers a valuable emerging approach for conquering the therapeutical deficiency of PDT.

Orthogonal Trichromatic Upconversion with High Color Purity in Core-Shell Nanoparticles for a Full-Color Display

Materials with tunable emission colors has attracted increasing interest in both fundamental research and applications. As a key member of light-emitting materials family, lanthanide doped upconversion nanoparticles (UCNPs) have been intensively demonstrated to emit light in any color upon near-infrared excitation. However, realizing the trichromatic emission in UCNPs with a fixed composition remains a great challenge. Here, without excitation pulsed modulation and three different near-infrared pumping, we report an experimental design to fine-control emission in the full color gamut from core-shell-structured UCNPs by manipulating the energy migration through dual-channel pump scheme. We also demonstrate their potential application in full-color display. These findings may benefit the future development of convenient and versatile optical methos for multicolor tuning and open up the possibility of constructing full-color volumetric display systems with high spatiotemporal resolution.

NIR-II Luminescent and Multi-Responsive Rare Earth Nanocrystals for Improved Chemodynamic Therapy

Chemodynamic therapy (CDT) based on the Fe²⁺-mediated Fenton reaction can amplify intracellular oxidative stress by producing toxic •OH. However, the high-dose need for Fe²⁺ delivery in tumors and its significant cytotoxicity to normal tissues set a challenge. Therefore, a controllable delivery to activate the Fenton reaction and enhance Fe²⁺ tumor accumulation has become an approach to solve this conflict. Herein, we report a rare-earth-nanocrystal (RENC)-based Fe²⁺ delivery system using light-control techniques and DNA nanotechnology to realize programmable Fe²⁺ delivery. Ferrocenes, the source of Fe²⁺, are modified on the surface of RENCs through pH-responsive DNAs, which are further shielded by a PEG layer to elongate blood circulation and "turn off" the cytotoxicity of ferrocene. The up-/down-conversion dual-mode emissions of RENCs endow the delivery system with both capabilities of diagnosis and delivery control. The down-conversion NIR-II fluorescence can locate tumors. Consequently, up-conversion UV light spatiotemporally activates the catalytic activity of Fe²⁺ by shedding off the protective PEG layer. The exposed ferrocene-DNAs not only can "turn on" Fenton catalytic activity but also respond to tumor acidity, driving cross-linking and enhanced Fe²⁺ enrichment in tumors by 4.5-fold. Accordingly, this novel design concept will be inspiring for developing CDT nanomedicines in the future.

Surface Engineering of Lanthanide Nanoparticles for Oncotherapy

Surface-modified lanthanide nanoparticles have been widely developed as an emerging class of therapeutics for cancer treatment because they exhibit several unique properties. First, lanthanide nanoparticles exhibit a variety of diagnostic capabilities suitable for various image-guided therapies. Second, a large number of therapeutic molecules can be accommodated on the surface of lanthanide nanoparticles, which can simultaneously achieve combined cancer therapy. Third, multivalent targeting ligands on lanthanide nanoparticles can be easily modified to achieve high affinity and specificity for target cells. Last but not least, lanthanide nanoparticles can be engineered for spatially and temporally controlled tumor therapy, which is critical for developing precise and personalized tumor therapy. Surface-modified lanthanide-doped nanoparticles are widely used in cancer phototherapy. This is due to their unique optical properties, including large anti-Stokes shifts, long-lasting luminescence, high photostability, and the capacity for near-infrared or X-ray excitation. Upon near-infrared irradiation, these nanoparticles can emit ultraviolet to visible light, which activates photosensitizers and photothermal agents to destroy tumor cells. Surface modification with special ligands that respond to tumor microenvironment changes, such as acidic pH, hypoxia, or redox reactions, can turn lanthanide nanoparticles into a smart nanoplatform for light-guided tumor chemotherapy and gene therapy. Surface-engineered lanthanide nanoparticles can include antigens that elicit tumor-specific immune responses, as well as immune activators that boost immunity, allowing distant and metastatic tumors to be eradicated. The design of ligands and surface chemistry is crucial for improving cancer therapy without causing side effects. In this Account, we classify surface-modified lanthanide nanoparticles for tumor therapy into four main domains: phototherapy, radiotherapy, chemotherapy, and biotherapy. We begin by introducing fundamental bioapplications and then discuss recent developments in tumor phototherapy (photodynamic therapy and photothermal therapy), radiotherapy, chemotherapy, and biotherapy (gene therapy and immunotherapy). We also assess the viability of a variety of strategies for eliminating tumor cells through innovative pathways. Finally, future opportunities and challenges for the development of more efficient lanthanide nanoprobes are discussed.

Inducible Degradation of Oncogenic Nucleolin Using an Aptamer-Based PROTAC

While proteolysis-targeting chimeras (PROTACs) are showing promise for targeting previously undruggable molecules, their application has been limited by difficulties in identifying suitable ligands and undesired on-target toxicity. Aptamers can virtually recognize any protein through their unique and switchable conformations. Here, by exploiting aptamers as targeting warheads, we developed a novel strategy for inducible degradation of undruggable proteins. As a proof of concept, we chose oncogenic nucleolin (NCL) as the target and generated a series of NCL degraders, and demonstrated that dNCL#T1 induced NCL degradation in a ubiquitin-proteasome-dependent manner, thereby inhibiting NCL-mediated breast cancer cell proliferation. To reduce on-target toxicity, we further developed a light-controllable PROTAC, opto-dNCL#T1, by introducing a photolabile complementary oligonucleotide to hybridize with dNCL#T1. UVA irradiation liberated dNCL#T1 from caged opto-dNCL#T1, leading to dNCL#T1 activation and NCL degradation. These results indicate that aptamer-based PROTACs are a viable alternative approach to degrade proteins of interest in a highly tunable manner.

Stimuli-responsive nucleic acid nanostructures for efficient drug delivery

Based on complementary base pairing, nucleic acid molecules have acted as engineerable building blocks to prepare versatile nanostructures with unique shapes and sizes. Benefiting from excellent programmability and biocompatibility, rationally designed nucleic acid nanostructures have been widely employed in biomedical applications. With the development of the chemical biology of nucleic acids, various stimuli-responsive nucleic acid nanostructures have been constructed by tailored chemical modification with multifunctional components. In this minireview, we summarize the representative and latest research about the employment of stimuli-responsive nucleic acid nanostructures for drug delivery in response to endogenous and exogenous stimuli (redox gradient, pH, nuclease, biomacromolecule, and light). We also discuss the broad prospects and remaining challenges of nucleic acid nanotechnology in biomedical applications.

A pH-Responsive Covalent Nanoscale Device Enhancing Temporal and Force Stability for Specific Tumor Imaging

Approaches to DNA probe-mediated precision medicine have been extensively explored for the diagnosis and treatment of diverse types of cancer. Despite this, simple nanoscale devices with the required recognition specificity and sensitivity for clinical application have remained elusive until now. Here, we report a pH-driven covalent nanoscale device that integrates pH-responsive, switchable structure and proximity-driven covalent cross-linking. A tumor acidic, pH-driven mechanism eliminates "on-target, off-tumor" nonspecific recognition. By manipulating covalent binding to target molecule on the cell surface, this nanodevice avoids binding-then-shedding to improve the sensitivity of tumor recognition. We envision that this pH-driven covalent nanoscale device will inspire more clinical applications toward specific, long-term tumor imaging in the cancer microenvironment.

Recent Trends and Developments in Multifunctional Nanoparticles for Cancer Theranostics

Conventional anticancer treatments, such as radiotherapy and chemotherapy, have significantly improved cancer therapy. Nevertheless, the existing traditional anticancer treatments have been reported to cause serious side effects and resistance to cancer and even to severely affect the quality of life of cancer survivors, which indicates the utmost urgency to develop effective and safe anticancer treatments. As the primary focus of cancer nanotheranostics, nanomaterials with unique surface chemistry and shape have been investigated for integrating cancer diagnostics with treatment techniques, including guiding a prompt diagnosis, precise imaging, treatment with an effective dose, and real-time supervision of therapeutic efficacy. Several theranostic nanosystems have been explored for cancer diagnosis and treatment in the past decade. However, metal-based nanotheranostics continue to be the most common types of nonentities. Consequently, the present review covers the physical characteristics of effective metallic, functionalized, and hybrid nanotheranostic systems. The scope of coverage also includes the clinical advantages and limitations of cancer nanotheranostics. In light of these viewpoints, future research directions exploring the robustness and clinical viability of cancer nanotheranostics through various strategies to enhance the biocompatibility of theranostic nanoparticles are summarised.

Functionalized-DNA nanostructures as potential targeted drug delivery systems for cancer therapy

Seeman's pioneer idea has led to the foundation of DNA nanostructures, resulting in a remarkable advancement in DNA nanotechnology. Over the last few decades, remarkable advances in drug delivery techniques have resulted in the self-assembly of DNA for encapsulating candidate drug molecules. The nuclear targeting capability of DNA nanostructures is lies within their high spatial addressability and tremendous potential for active targeting. However, effective programming and assembling those DNA molecules remains a challenge, making the path to DNA nanostructures for real-world applications difficult. Because of their small size, most nanostructures are self-capable of infiltrating into the tumor cellular environment. Furthermore, to enable controlled and site-specific delivery of encapsulated drug molecules, DNA nanostructures are functionalized with special moieties that allow them to bind specific targets and release cargo only at targeted sites rather than non-specific sites, resulting in the prevention/limitation of cellular toxicity. In light of this, the current review seeks to shed light on the versatility of the DNA molecule as a targeting and encapsulating moiety for active drugs in order to achieve controlled and specific drug release with spatial and temporal precision. Furthermore, this review focused on the challenges associated with the construction of DNA nanostructures as well as the most recent advances in the functionalization of DNA nanostructures using various materials for controlled and targeted delivery of medications for cancer therapy.

Upconversion Luminescence-Boosted Escape of DNAzyme from Endosomes for Enhanced Gene-Silencing Efficacy

Despite the enormous potential of DNAzyme for gene therapy, its efficacy is hampered by the limited endosomal escape capability. Here, we develop a near-infrared (NIR) light-controlled DNAzyme delivery platform to achieve enhanced gene-silencing efficacy. The nanoplatform is composed of therapeutic DNAzyme, photosensitizers (PSs) and upconversion nanoparticles (UCNPs) that can convert NIR light to visible light. The system allows NIR light-activatable generation of cytotoxic reactive oxygen species due to the energy transfer from the UCNPs to PSs, which boosts the endosomal escape of DNAzyme for an improved gene-silencing efficacy. We demonstrate that the nanocomposites represent a promising platform to integrate DNAzyme-based gene therapy with NIR light-triggered photodynamic therapy for combinational tumor treatment. This work highlights a robust approach to combat the current limitations of DNAzyme delivery systems.

Specific-Tuning Band Structure in Hetero-Semiconductor Nanorods to Match with Reduction of Oxygen Molecules for Low-Intensity Yet Highly Effective Sonodynamic/Hole Therapy of Tumors

Sonosensitizers-assisted sonodynamic therapy (SDT) has been emerging as a promising treatment for cancers, and yet few specific regulations of band structure of sonosensitizers have been reported in relation to oxygen in tissues. Herein, by a gradient doping technique to modulate the band structure of hetero-semiconductor nanorods, it is found that the reduction potential of band-edge is very critical to reactive oxygen species (ROS) production under low-intensity ultrasound (US) irradiation and particularly, when aligned with the reduction of oxygen, ROS generation is found to be most significantly enhanced. Withal, US-generated oxidation holes are found to be effective in consuming overexpressed glutathione in tumor lesions, which amplifies cellular oxidative stress and finally induces tumor cell death. Moreover, the intrinsic fluorescence property of semiconductors provides imaging capability to illumine tumor area and guide the SDT process. This study demonstrates that the reduction potential state of sonosensitizers is of crucial importance in ROS generation and the proposed reduction potential-tailored hetero-semiconductor nanorods materialize low-intensity US irradiation yet highly effective SDT and synergetic hole therapy of tumors with imaging guidance and reduced radiation injury.

Spatially Selective Monitoring of Subcellular Enzyme Dynamics in Response to Mitochondria-Targeted Photodynamic Therapy

Tracking spatial and temporal dynamics of bioactive molecules such as enzymes responding to therapeutic treatment is highly important for understanding of the related functions. However, in situ molecular imaging at subcellular level during photodynamic therapy (PDT) has been hampered by the limitations of existing methods. Herein, we present a multifunctional nanoplatform (termed as UR-HAPT) that is able to simultaneously monitor subcellular dynamics of human apurinic/apyrimidinic endonuclease 1 (APE1) during the near-infrared (NIR) light-mediated PDT. UR-HAPT was constructed by the combination of an upconversion nanoparticle-based PDT design and a mitochondria-targeting strategy with an APE1-responsive DNA reporter. Benefiting from the gain-of-function approach, activatable mitochondrial accumulation of APE1 in response to the oxidative stress was observed during the NIR light-triggered, mitochondria-targeted PDT process. We envision that this nanoplatform can be applicable to screen and evaluate potential enzyme inhibitors to improve the PDT efficacy.

Upconversion nanomaterials and delivery systems for smart photonic medicines and healthcare devices

In the past decade, upconversion (UC) nanomaterials have been extensively investigated for the applications to photomedicines with their unique features including biocompatibility, near-infrared (NIR) to visible conversion, photostability, controllable emission bands, and facile multi-functionality. These characteristics of UC nanomaterials enable versatile light delivery for deep tissue biophotonic applications. Among various stimuli-responsive delivery systems, the light-responsive delivery process has been greatly advantageous to develop spatiotemporally controllable on-demand "smart" photonic medicines. UC nanomaterials are classified largely to two groups depending on the photon UC pathway and compositions: inorganic lanthanide-doped UC nanoparticles and organic triplet-triplet annihilation UC (TTA-UC) nanomaterials. Here, we review the current-state-of-art inorganic and organic UC nanomaterials for photo-medicinal applications including photothermal therapy (PTT), photodynamic therapy (PDT), photo-triggered chemo and gene therapy, multimodal immunotherapy, NIR mediated neuromodulations, and photochemical tissue bonding (PTB). We also discuss the future research direction of this field and the challenges for further clinical development.