Sequence‐Dependent DNA Functionalization of Upconversion Nanoparticles and Their Programmable Assemblies

Evaluation of Pharmacokinetics, Immunogenicity, and Immunotoxicity of DNA Tetrahedral and DNA Polymeric Nanostructures

Deoxyribonucleic acid (DNA) nanostructures have been extensively explored in biomedical applications and have emerged as a promising platform for drug delivery, bioanalysis, and therapeutics. Their in vivo behaviors have received much attention, a prerequisite for clinical applications. Herein, the pharmacokinetics, immunogenicity, and immunotoxicity of two representative DNA nanostructures: DNA tetrahedron (TDN) and DNA nanoparticle (DNP) are studied. The pharmacokinetics of DNA nanostructures are monitored in a mouse model via tracking of 32P radiolabeled, and the half-lives of TDN and DNP are 9.88 and 19.80 min, respectively. TDN and DNP preferentially accumulate in the liver and kidney in one half-life and are metabolized through liver, kidney, and excreta after 24 h. Meanwhile, TDN and DNP elicit a weak pro-inflammatory immune response with low immunogenicity and are non-immunotoxic, as shown by immunotoxicity evaluation, histopathology, and serum biochemical index analysis. This research shows that the DNA nanostructures of TDN and DNP are safe for biological systems, indicating that TDN and DNP can be developed as promising therapeutic platforms in biomedicine.

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.

Arsenic Nanoparticles Trigger Apoptosis via Anoikis Induction in OECM-1 Cells

Arsenic compounds have been used as therapeutic alternatives for several diseases including cancer. In the following work, we obtained arsenic nanoparticles (AsNPs) produced by an anaerobic bacterium from the Salar de Ascotán, in northern Chile, and evaluated their effects on the human oral squamous carcinoma cell line OECM-1. Resazurin reduction assays were carried out on these cells using 1-100 µM of AsNPs, finding a concentration-dependent reduction in cell viability that was not observed for the non-tumoral gastric mucosa-derived cell line GES-1. To establish if these effects were associated with apoptosis induction, markers like Bcl2, Bax, and cleaved caspase 3 were analyzed via Western blot, executor caspases 3/7 via luminometry, and DNA fragmentation was analyzed by TUNEL assay, using 100 µM cisplatin as a positive control. OECM-1 cells treated with AsNPs showed an induction of both extrinsic and intrinsic apoptotic pathways, which can be explained by a significant decrease in P-Akt/Akt and P-ERK/ERK relative protein ratios, and an increase in both PTEN and p53 mRNA levels and Bit-1 relative protein levels. These results suggest a prospective mechanism of action for AsNPs that involves a potential interaction with extracellular matrix (ECM) components that reduces cell attachment and subsequently triggers anoikis, an anchorage-dependent type of apoptosis.

Sunflower Pollen-Derived Microspheres Selectively Absorb DNA for microRNA Detection

Herein, we report the finding that a naturally sunflower pollen-derived microspheres (HSECs) with hierarchical structures can selectively absorb polyC and polyA with high efficiency and affinity. HSECs exhibit the capability to selectively absorb polyC and polyA ssDNA under neutral and acidic conditions. It has been observed that the presence of metal cations, specifically Ca2+, enhances the absorption efficiency of HSECs. Mechanically, this absorption phenomenon can be attributed to both electrostatic interactions and cation-π interactions. Such an appealing property enables the functionalization of HSECs for broad potential biomedical applications, such as microRNA detection.

Single-particle Förster resonance energy transfer from upconversion nanoparticles to organic dyes

Single-particle detection and sensing, powered by Förster resonance energy transfer (FRET), offers precise monitoring of molecular interactions and environmental stimuli at a nanometric resolution. Despite its potential, the widespread use of FRET has been curtailed by the rapid photobleaching of traditional fluorophores. This study presents a robust single-particle FRET platform utilizing upconversion nanoparticles (UCNPs), which stand out for their remarkable photostability, making them superior to conventional organic donors for energy transfer-based assays. Our comprehensive research demonstrates the influence of UCNPs' size, architecture, and dye selection on the efficiency of FRET. We discovered that small particles (∼14 nm) with a Yb3+-enriched outermost shell exhibit a significant boost in FRET efficiency, a benefit not observed in larger particles (∼25 nm). 25 nm UCNPs with an inert NaLuF4 shell demonstrated a comparable level of emission enhancement via FRET as those with a Yb3+-enriched outermost shell. At the single-particle level, these FRET-enhanced UCNPs manifested an upconversion green emission intensity that was 8.3 times greater than that of their unmodified counterparts, while maintaining notable luminescence stability. Our upconversion FRET system opens up new possibilities for developing more effective high-brightness, high-sensitivity single-particle detection, and sensing modalities.

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.

Z-Scheme Heterojunction Excited by DNA-Programmed Upconversion Nanotransducers for a Near-Infrared Light-Actuated Lab-on-Paper Device

Herein, a flexible near-infrared (NIR) light-actuated photoelectrochemical (PEC) lab-on-paper device was constructed toward miRNA-122 detection, utilizing the combination of DNA-programmed NaYF4/Yb,Tm upconversion nanoparticles (UCNPs) and the Z-scheme AgI/WO3 heterojunction grown in situ on gold nanoparticle-decorated 3D cellulose fibers. The UCNPs were employed as light transducers for converting NIR light into ultraviolet/visible (UV/vis) light to excite the nanojunction. The multiple diffraction of NaYF4/Yb,Tm matched the absorption band of the Z-scheme AgI/WO3 heterojunction, resulting in enhanced PEC photocurrent output. This prepared Z-scheme heterojunction effectively directed charge migration and highly facilitated the electron-hole pair separation. Target miRNA-122 activated the nonenzyme catalytic hairpin assembly signal amplification strategy, generating duplexes which caused the exfoliation of NaYF4/Yb,Tm UCNPs from the biosensor electrode and lowered the photocurrent under 980 nm irradiation. Under optimized circumstances, the proposed NIR-actuated PEC lab-on-paper device presented accurate miRNA-122 detection within a wide linear range of 10 fM-100 nM with a low limit of detection of 2.32 fM, providing a reliable strategy in the exploration of NIR-actuated PEC biosensors for low-cost, high-performance bioassay in clinical applications.

DNA-functionalized metal or metal-containing nanoparticles for biological applications

The conjugation of DNA molecules with metal or metal-containing nanoparticles (M/MC NPs) has resulted in a number of new hybrid materials, enabling a diverse range of novel biological applications in nanomaterial assembly, biosensor development, and drug/gene delivery. In such materials, the molecular recognition, gene therapeutic, and structure-directing functions of DNA molecules are coupled with M/MC NPs. In turn, the M/MC NPs have optical, catalytic, pore structure, or photodynamic/photothermal properties, which are beneficial for sensing, theranostic, and drug loading applications. This review focuses on the different DNA functionalization protocols available for M/MC NPs, including gold NPs, upconversion NPs, metal-organic frameworks, metal oxide NPs and quantum dots. The biological applications of DNA-functionalized M/MC NPs in the treatment or diagnosis of cancers are discussed in detail.

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.

How Synthesis of Algal Nanoparticles Affects Cancer Therapy? - A Complete Review of the Literature

The necessity to engineer sustainable nanomaterials for the environment and human health has recently increased. Due to their abundance, fast growth, easy cultivation, biocompatibility and richness of secondary metabolites, algae are valuable biological source for the green synthesis of nanoparticles (NPs). The aim of this review is to demonstrate the feasibility of using algal-based NPs for cancer treatment. Blue-green, brown, red and green micro- and macro-algae are the most commonly participating algae in the green synthesis of NPs. In this process, many algal bioactive compounds, such as proteins, carbohydrates, lipids, alkaloids, flavonoids and phenols, can catalyze the reduction of metal ions to NPs. In addition, many driving factors, including pH, temperature, duration, static conditions and substrate concentration, are involved to facilitate the green synthesis of algal-based NPs. Here, the biosynthesis, mechanisms and applications of algal-synthesized NPs in cancer therapy have been critically discussed. We also reviewed the effective role of algal synthesized NPs as anticancer treatment against human breast, colon and lung cancers and carcinoma.

Development of Solid Lipid Nanoparticles for Controlled Amiodarone Delivery

In various drug delivery systems, solid lipid nanoparticles are dominantly lipid-based nanocarriers. Amiodarone hydrochloride is an antiarrhythmic agent used to treat severe rhythm disturbances. It has variable and hard-to-predict absorption in the gastrointestinal tract because of its low solubility and high permeability. The aims of this study were to improve its solubility by encapsulating amiodarone into solid lipid nanoparticles using two excipients-Compritol® 888 ATO (pellets) (C888) as a lipid matrix and Transcutol® (T) as a surfactant. Six types of amiodarone-loaded solid lipid nanoparticles (AMD-SLNs) were obtained using a hot homogenization technique followed by ultrasonication with varying sonication parameters. AMD-SLNs were characterized by their size distribution, polydispersity index, zeta potential, entrapment efficiency, and drug loading. Based on the initial evaluation of the entrapment efficiency, only three solid lipid nanoparticle formulations (P1, P3, and P5) were further tested. They were evaluated through scanning electron microscopy, Fourier-transform infrared spectrometry, near-infrared spectrometry, thermogravimetry, differential scanning calorimetry, and in vitro dissolution tests. The P5 formulation showed optimum pharmaco-technical properties, and it had the greatest potential to be used in oral pharmaceutical products for the controlled delivery of amiodarone.

Erythrocyte membrane-camouflaged DNA-functionalized upconversion nanoparticles for tumor-targeted chemotherapy and immunotherapy

A synergistic combination of treatment with immunogenic cell death (ICD) inducers and immunoadjuvants may be a practical way to boost the anticancer response and successfully induce an immune response. The use of HR@UCNPs/CpG-Apt/DOX, new biomimetic drug delivery nanoparticles generated to combat breast cancer, is reported here as a unique strategy to produce immunogenicity and boost cancer immunotherapy. HR@UCNPs/CpG-Apt/DOX (HR-UCAD) consists of two parts. The core is composed of an immunoadjuvant CpG (a toll-like receptor 9 agonist) fused with a dendritic cell-specific aptamer sequence (CpG-Apt) to decorate upconversion nanoparticles (UCNPs) with the successful intercalation of doxorubicin (DOX) into the consecutive base pairs of Apt-CpG to construct an immune nanodrug UCNPs@CpG-Apt/DOX. The targeting molecule hyaluronic acid (HA) was inserted into a red blood cell membrane (RBCm) to form the shell (HR). HR-UCAD possessed a strong capacity to specifically induce ICD. Following DOX-induced ICD of cancer cells, sufficient exposure to tumor antigens and UCNPs@CpG-Apt (UCA) activated the tumor-specific immune response and reversed the immunosuppressive tumor microenvironment. In addition, HR-UCAD has good biocompatibility and increases the active tumor-targeting effect. Furthermore, HR-UCAD exhibits excellent near-infrared upconversion luminescence emission at 804 nm under irradiation with a 980 nm laser, which has great potential in biomedical imaging. Thus, the RBCm-camouflaged drug delivery system is a promising targeted chemotherapy and immunotherapy nanocomplex that could be used for effective targeted breast cancer treatment.

Bioorthogonal Disassembly of Hierarchical DNAzyme Nanogel for High-Performance Intracellular microRNA Imaging

Rolling circle amplification (RCA) enables the facile construction of compact and versatile DNA nanoassemblies which are yet rarely explored for intracellular analysis. This is might be ascribed to the uncontrollable and inefficient probe integration/activation. Herein, by encoding with tandem allosteric deoxyribozyme (DNA-cleaving DNAzyme), a multifunctional RCA nanogel was established for realizing the efficient intracellular microRNA imaging via the successive activation of the RCA-disassembly module and signal amplification module. The endogenous microRNA stimulates the precise degradation of DNA nanocarriers, thus leading to the efficient exposure of RCA-entrapped DNAzyme biocatalyst for an amplified readout signal. Our bioorthogonal DNAzyme disassembly strategy achieved the robust analysis of intracellular biomolecules, thus showing more prospects in clinical diagnosis.

Rapid point-of-care detection of SARS-CoV-2 RNA with smartphone-based upconversion luminescence diagnostics

Accurate COVID-19 screening via molecular technologies is still hampered by bulky instrumentation, complicated procedure, high cost, lengthy testing time, and the need for specialized personnel. Herein, we develop point-of-care upconversion luminescence diagnostics (PULD), and a streamlined smartphone-based portable platform facilitated by a ready-to-use assay for rapid SARS-CoV-2 nucleocapsid (N) gene testing. With the complementary oligo-modified upconversion nanoprobes and gold nanoprobes specifically hybridized with the target N gene, the luminescence resonance energy transfer effect leads to a quenching of fluorescence intensity that can be detected by the easy-to-use diagnostic system. A remarkable detection limit of 11.46 fM is achieved in this diagnostic platform without the need of target amplification, demonstrating high sensitivity and signal-to-noise ratio of the assay. The capability of the developed PULD is further assessed by probing 9 RT-qPCR-validated SARS-CoV-2 variant clinical samples (B.1.1.529/Omicron) within 20 min, producing reliable diagnostic results consistent with those obtained from a standard fluorescence spectrometer. Importantly, PULD is capable of identifying the positive COVID-19 samples with superior sensitivity and specificity, making it a promising front-line tool for rapid, high-throughput screening and infection control of COVID-19 or other infectious diseases.

Assembly of Rolling Circle Amplification-Produced Ultralong Single-Stranded DNA to Construct Biofunctional DNA Materials

The Review by Yang, Yao and colleagues (DOI: 10.1002/chem.202202673) describes recent developments in biofunctional DNA hydrogels and DNA nanocomplexes based on rolling circle amplification (RCA) and introduces assembly strategies and functionalization methods of the ultralong single-strand DNA produced by RCA to construct biofunctional materials.

Recent Development in Sensitizers for Lanthanide-Doped Upconversion Luminescence

The attractive features of lanthanide-doped upconversion luminescence (UCL), such as high photostability, nonphotobleaching or photoblinking, and large anti-Stokes shift, have shown great potentials in life science, information technology, and energy materials. Therefore, UCL modulation is highly demanded toward expected emission wavelength, lifetime, and relative intensity in order to satisfy stringent requirements raised from a wide variety of areas. Unfortunately, the majority of efforts have been devoted to either simple codoping of multiple activators or variation of hosts, while very little attention has been paid to the critical role that sensitizers have been playing. In fact, different sensitizers possess different excitation wavelengths and different energy transfer pathways (to different activators), which will lead to different UCL features. Thus, rational design of sensitizers shall provide extra opportunities for UCL tuning, particularly from the excitation side. In this review, we specifically focus on advances in sensitizers, including the current status, working mechanisms, design principles, as well as future challenges and endeavor directions.

Protein-Mimicking Nanoparticles in Biosystems

Proteins are essential elements for almost all life activities. The emergence of nanotechnology offers innovative strategies to create a diversity of nanoparticles (NPs) with intrinsic capacities of mimicking the functions of proteins. These artificial mimics are produced in a cost-efficient and controllable manner, with their protein-mimicking performances comparable or superior to those of natural proteins. Moreover, they can be endowed with additional functionalities that are absent in natural proteins, such as cargo loading, active targeting, membrane penetrating, and multistimuli responding. Therefore, protein-mimicking NPs have been utilized more and more often in biosystems for a wide range of applications including detection, imaging, diagnosis, and therapy. To highlight recent progress in this broad field, herein, representative protein-mimicking NPs that fall into one of the four distinct categories are summarized: mimics of enzymes (nanozymes), mimics of fluorescent proteins, NPs with high affinity binding to specific proteins or DNA sequences, and mimics of protein scaffolds. This review covers their subclassifications, characteristic features, functioning mechanisms, as well as the extensive exploitation of their great potential for biological and biomedical purposes. Finally, the challenges and prospects in future development of protein-mimicking NPs are discussed.

Nanocomposites based on lanthanide-doped upconversion nanoparticles: diverse designs and applications

Lanthanide-doped upconversion nanoparticles (UCNPs) have aroused extraordinary interest due to the unique physical and chemical properties. Combining UCNPs with other functional materials to construct nanocomposites and achieve synergistic effect abound recently, and the resulting nanocomposites have shown great potentials in various fields based on the specific design and components. This review presents a summary of diverse designs and synthesis strategies of UCNPs-based nanocomposites, including self-assembly, in-situ growth and epitaxial growth, as well as the emerging applications in bioimaging, cancer treatments, anti-counterfeiting, and photocatalytic fields. We then discuss the challenges, opportunities, and development tendency for developing UCNPs-based nanocomposites.

Recent Advances in Self-Assembled DNA Nanostructures for Bioimaging

DNA nanotechnology has been proven to be a powerful platform to assist the development of imaging probes for biomedical research. The attractive features of DNA nanostructures, such as nanometer precision, controllable size, programmable functions, and biocompatibility, have enabled researchers to design and customize DNA nanoprobes for bioimaging applications. However, DNA probes with low molecular weights (e.g., 10-100 nt) generally suffer from low stability in physiological buffer environments. To improve the stability of DNA nanoprobes in such environments, DNA nanostructures can be designed with relatively larger sizes and defined shapes. In addition, the established modification methods for DNA nanostructures are also essential in enhancing their properties and performances in a physiological environment. In this review, we begin with a brief recap of the development of DNA nanostructures including DNA tiles, DNA origami, and multifunctional DNA nanostructures with modifications. Then we highlight the recent advances of DNA nanostructures for bioimaging, emphasizing the latest developments in probe modifications and DNA-PAINT imaging. Multiple imaging modules for intracellular biomolecular imaging and cell membrane biomarkers recognition are also summarized. In the end, we discuss the advantages and challenges of applying DNA nanostructures in bioimaging research and speculate on its future developments.

Nanoparticles in Clinical Translation for Cancer Therapy

The advent of cancer therapeutics brought a paradigm shift from conventional therapy to precision medicine. The new therapeutic modalities accomplished through the properties of nanomaterials have extended their scope in cancer therapy beyond conventional drug delivery. Nanoparticles can be channeled in cancer therapy to encapsulate active pharmaceutical ingredients and deliver them to the tumor site in a more efficient manner. This review enumerates various types of nanoparticles that have entered clinical trials for cancer treatment. The obstacles in the journey of nanodrug from clinic to market are reviewed. Furthermore, the latest developments in using nanoparticles in cancer therapy are also highlighted.

Aptamer-based biosensing through the mapping of encoding upconversion nanoparticles for sensitive CEA detection

An aptamer-based assay through the mapping and enumeration of encoding UCNPs for digital detection of CEA is reported.

miR122-controlled all-in-one nanoplatform for in situ theranostic of drug-induced liver injury by visualization imaging guided on-demand drug release

Drug-induced liver injury (DILI) is a challenging clinical problem with respect to both diagnosis and management. As a newly emerging biomarker of liver injury, miR122 shows great potential in early and sensitive in situ detection of DILI. Glycyrrhetinic acid (GA) possesses desirable therapeutic effect on DILI, but its certain dose-dependent side effects after long-term and/or high-dose administration limit its clinical application. In this study, in order to improve the precise diagnosis and effective treatment of DILI, GA loaded all-in-one theranostic nanoplatform was designed by assembling of upconversion nanoparticles and gold nanocages. As a proof of concept, we demonstrated the applicability of this single-wavelength laser-triggered theranostic nanoplatform for the spatiotemporally controllable in situ imaging of DILI and miR122-controlled on-demand drug release in vitro and in vivo. This novel nanoplatform opens a promising avenue for the clinical diagnosis and treatment of DILI.

Engineering DNA on the Surface of Upconversion Nanoparticles for Bioanalysis and Therapeutics

Surface modification of inorganic nanomaterials with biomolecules has enabled the development of composites integrated with extensive properties. Lanthanide ion-doped upconversion nanoparticles (UCNPs) are one class of inorganic nanomaterials showing optical properties that convert photons of lower energy into higher energy. Additionally, DNA oligonucleotides have exhibited powerful capabilities for organizing various nanomaterials with versatile topological configurations. Through rational design and nanotechnology, DNA-based UCNPs offer predesigned functionality and potential. To fully harness the capabilities of UCNPs integrated with DNA, various DNA-UCNP composites have been developed for diagnosis and therapeutics. In this review, beginning with the introduction of the UCNPs and the conjugation of DNA strands on the surface of UCNPs, we present an overview of the recent progress of DNA-UCNP composites while focusing on their applications for bioanalysis and therapeutics.

DNA-based plasmonic nanostructures and their optical and biomedical applications

In the past few decades, DNA nanotechnology has been developed a lot due to their appealing features such as structural programmability and easy functionalization. In the emerging field of DNA nanotechnology, DNA molecules are regarded not only as biological information carriers but also as building blocks in the assembly of various two-dimensional and three-dimensional nanostructures, serving as outstanding templates for the bottom-up fabrication of plasmonic nanostructures. By arranging nanoparticles with different components and morphologies on the predesigned DNA templates, various static and dynamic plasmonic nanostructures with tailored optical properties have been obtained. In this review, we summarized recent advances in the design and construction of static and dynamic DNA-based plasmonic nanostructures. In addition, we addressed their emerging applications in the fields of optics and biosensors. At the end of this review, the open questions and future directions of DNA-based plasmonic nanostructure are also discussed.

A luminescent view of the clickable assembly of LnF3 nanoclusters

Nanoclusters (NCs) bridge the gap between atoms and nanomaterials in not only dimension but also physicochemical properties. Precise chemical and structural control, as well as clear understanding of formation mechanisms, have been important to fabricate NCs with high performance in optoelectronics, catalysis, nanoalloys, and energy conversion and harvesting. Herein, taking advantage of the close chemical properties of Ln³⁺ (Ln = Eu, Nd, Sm, Gd, etc.) and Gd³⁺–Eu³⁺ energy transfer ion-pair, we report a clickable LnF₃ nanoparticle assembly strategy allowing reliable fabrication of diversely structured NCs, including single-component, dimeric, core-shelled/core-shell-shelled, and reversely core-shelled/core-shell-shelled, particularly with synergized optical functionalities. Moreover, the purposely-embedded dual luminescent probes offer great superiority for in situ and precise tracking of tiny structural variations and energy transfer pathways within complex nanoarchitectures.

Precisely controlling the chemical composition and structure of nanoclusters is an ongoing challenge. Here, the authors report a clickable assembly strategy to construct widely varied lanthanide nanoclusters with synergized optical functionalities.

Exploring Heterostructured Upconversion Nanoparticles: From Rational Engineering to Diverse Applications

Upconversion nanoparticles (UCNPs) represent a class of optical nanomaterials that can convert low-energy excitation photons to high-energy fluorescence emissions. On the basis of UCNPs, heterostructured UCNPs, consisting of UCNPs and other functional counterparts (metals, semiconductors, polymers, etc.), present an intriguing system in which the physicochemical properties are largely influenced by the entire assembled particle and also by the morphology, dimension, and composition of each individual component. As multicomponent nanomaterials, heterostructured UCNPs can overcome challenges associated with a single component and exhibit bifunctional or multifunctional properties, which can further expand their applications in bioimaging, biodetection, and phototherapy. In this review, we provide a summary of recent achievements in the field of heterostructured UCNPs in the aspects of construction strategies, synthetic approaches, and types of heterostructured UCNPs. This review also summarizes the trends in biomedical applications of heterostructured UCNPs and discusses the challenges and potential solutions in this field.

Self-assembly of colloidal inorganic nanocrystals: nanoscale forces, emergent properties and applications

The self-assembly of colloidal nanoparticles has made it possible to bridge the nanoscopic and macroscopic worlds and to make complex nanostructures. The nanoparticle-mediated assembly enables many potential applications, from biodetection and nanomedicine to optoelectronic devices. Properties of assembled materials are determined not only by the nature of nanoparticle building blocks, but also by spatial positions of nanoparticles within the assemblies. A deep understanding of nanoscale interactions between nanoparticles is a prerequisite to controlling nanoparticle arrangement during assembly. In this review, we present an overview of interparticle interactions governing their assembly in a liquid phase. Considerable attention is devoted to examples that illustrate nanoparticle assembly into ordered superstructures using different types of building blocks, including plasmonic nanoparticles, magnetic nanoparticles, lanthanide-doped nanophosphors, and quantum dots. We also cover the physicochemical properties of nanoparticle ensembles, especially those arising from particle coupling effects. We further discuss future research directions and challenges in controlling self-assembly at a level of precision that is most crucial to technology development.

Polyvalent Metal Ion Promoted Adsorption of DNA Oligonucleotides by Montmorillonite

Montmorillonite (MMT) is a two-dimensional (2D) clay material. Its abundance on the early earth has attracted studies for its role in prebiotic reactions, and adsorption of DNA to MMT is potentially important for understanding the origin of life. Although several possible models of DNA adsorption on MMT have been established, a consensus on the adsorption mechanism has yet to be formed, thereby a fundamental adsorption study is performed here. Adding up to 300 mM NaCl failed to promote DNA adsorption on MMT, Al₂O₃, or SiO₂ nanoparticles. For polyvalent metals, DNA adsorption was achieved following the order Ce³⁺ > Cu²⁺ > Ni²⁺ > Zn²⁺. Among them, Ce³⁺ and Cu²⁺ inverted the surface charge of MMT to positive. In addition, using washing experiments, Cu²⁺- and Ce³⁺-mediated adsorption mainly depended on the DNA phosphate backbone, while Ni²⁺ and Zn²⁺ interacted with the backbone phosphate groups and adenine bases of DNA. Overall, these polyvalent metal ions promoted DNA adsorption via a cation bridge model. This research provides new insights into the surface interactions of MMT and DNA, which is conducive to future work on the interaction between clays and biopolymers.

Stronger Adsorption of Phosphorothioate DNA Oligonucleotides on Graphene Oxide by van der Waals Forces

Finding DNA sequences that can adsorb strongly on nanomaterials is critical for bioconjugate and biointerface chemistry. In most previous work, unmodified DNA with a phosphodiester backbone (PO DNA) were screened or selected for adsorption on inorganic surfaces. In this work, the adsorption of phosphorothioate (PS)-modified DNA (PS DNA) on graphene oxide (GO) is studied. By use of fluorescently labeled oligonucleotides as probes, all the tested PS DNA strands are adsorbed more strongly on GO compared to the PO DNA of the same sequence. The adsorption mechanism is probed by washing the adsorbed DNA with proteins, surfactants, and urea. Molecular dynamics simulations show that van der Waals forces are responsible for the tighter adsorption of PS DNA. Polycytosine (poly-C) DNA, in general, has a high affinity for the GO surface, and PS poly-C DNA can adsorb even stronger, making it an ideal anchoring sequence on GO. With this knowledge, noncovalent functionalization of GO with a diblock DNA is demonstrated, where a PS poly-C block is used to anchor on the surface. This conjugate achieves better hybridization than the PO DNA of the same sequence for hybridization with the complementary DNA.