Protein Corona Inhibits Endosomal Escape of Functionalized DNA Nanostructures in Living Cells

Photochemical Stabilization of Self-Assembled Spherical Nucleic Acids

Oligonucleotide therapeutics, including antisense oligonucleotides and small interfering RNA, offer promising avenues for modulating the expression of disease-associated proteins. However, challenges such as nuclease degradation, poor cellular uptake, and unspecific targeting hinder their application. To overcome these obstacles, spherical nucleic acids have emerged as versatile tools for nucleic acid delivery in biomedical applications. Our laboratory has introduced sequence-defined DNA amphiphiles which self-assemble in aqueous solutions. Despite their advantages, self-assembled SNAs can be inherently fragile due to their reliance on non-covalent interactions and fall apart in biologically relevant conditions, specifically by interaction with serum proteins. Herein, this challenge is addressed by introducing two methods of covalent crosslinking of SNAs via UV irradiation. Thymine photodimerization or disulfide crosslinking at the micellar interface enhance SNA stability against human serum albumin binding. This enhanced stability, particularly for disulfide crosslinked SNAs, leads to increased cellular uptake. Furthermore, this crosslinking results in sustained activity and accessibility for release of the therapeutic nucleic acid, along with improvement in unaided gene silencing. The findings demonstrate the efficient stabilization of SNAs through UV crosslinking, influencing their cellular uptake, therapeutic release, and ultimately, gene silencing activity. These studies offer promising avenues for further optimization and exploration of pre-clinical, in vivo studies.

AI-Based Prediction of Protein Corona Composition on DNA Nanostructures

DNA nanotechnology has emerged as a powerful approach to engineering biophysical tools, therapeutics, and diagnostics because it enables the construction of designer nanoscale structures with high programmability. Based on DNA base pairing rules, nanostructure size, shape, surface functionality, and structural reconfiguration can be programmed with a degree of spatial, temporal, and energetic precision that is difficult to achieve with other methods. However, the properties and structure of DNA constructs are greatly altered in vivo due to spontaneous protein adsorption from biofluids. These adsorbed proteins, referred to as the protein corona, remain challenging to control or predict, and subsequently, their functionality and fate in vivo are difficult to engineer. To address these challenges, we prepared a library of diverse DNA nanostructures and investigated the relationship between their design features and the composition of their protein corona. We identified protein characteristics important for their adsorption to DNA nanostructures and developed a machine-learning model that predicts which proteins will be enriched on a DNA nanostructure based on the DNA structures' design features and protein properties. Our work will help to understand and program the function of DNA nanostructures in vivo for biophysical and biomedical applications.

Elucidating the uptake and trafficking of nanostructured lipid carriers as delivery systems for miRNA

Cationic nanostructured lipid carriers (cNLCs) represent promising non-viral carriers for nucleic acids, such as miRNAs, forming stable self-assembled miRNA complexes due to electrostatic interactions. Prepared by high-pressure homogenization, cNLC formulations, both with and without Nile Red dye demonstrated stable particle sizes in the range of 100-120 nm and positive surface charges (>30 mV), which are necessary for effective cellular uptake. The miRNA complexes formed at mass ratios of 1:2.5 and 1:5 showed similar stability and size, with positive zeta potentials, as well as high cell viability (> 80 %) in 3T3-L1 and MCF-7 cell lines. The cellular uptake studies of miRNA:cNLC complexes in both cell lines revealed that uptake was time- and concentration-dependent, with rapid initial uptake in 30 min and a zig-zag pattern over 24 h. To elucidate the endocytosis mechanism of miRNA:cNLC complexes, 3T3-L1 and MCF-7 cells were incubated with different inhibitors (chlorpromazine, 5-[N-ethyl-N-isopropyl] amiloride, dynasore, nystatin, or sodium azide with 2-deoxy-d-glucose). Results showed significant inhibition of uptake at low temperatures and with ATP depletion, suggesting endocytosis, particularly macropinocytosis, as the main uptake mechanism in 3T3-L1 cells. In MCF-7 cells, the uptake was less inhibited by the substances, indicating the need for more specific methods to fully decipher the endocytic mechanisms involved. Confocal laser scanning microscopy images revealed that the complexes are internalized in vesicles, and are primarily localized in the juxtanuclear region, suggesting trafficking through the endolysosomal system. Colocalization study with LysoTracker™ Green DND-26 showed significant colocalization of miRNA:cNLC complexes with lysosomes in 3T3-L1 cells, indicating trafficking through the endolysosomal system. In MCF-7 cells, colocalization was lower, suggesting macropinocytosis as the primary uptake mechanism. Additional studies showed partial colocalization between labeled NLCs and miRNA, indicating that about 50 % of miRNA is released from NLCs within 30 min post-transfection.

Mitochondrial transfer of drug-loaded artificial mitochondria for enhanced anti-Glioma therapy through synergistic apoptosis/ferroptosis/immunogenic cell death

Mitochondrial targeting in gliomas represents a novel therapeutic strategy with significant potential to enhance drug sensitivity by effectively killing glioma cells at the mitochondrial level. In this study, we developed artificial mitochondria derived from mitochondrial membrane-based nanovesicles, enabling precise mitochondrial targeting of doxorubicin (Dox) to selectively eradicate cancer cells by amplifying multiple cell death pathways. It was found that Dox-encapsulating mitochondria-based nanovesicles (DOX-MitoNVs) exhibited an extraordinary ability to penetrate the blood-brain barrier (BBB), specifically targeting gliomas. By targeting mitochondria instead of locating at the nucleus, DOX-MitoNVs not only amplified Dox mediated apoptosis effects through the overloading of intracellular Ca2+ but also intensified ferroptosis by generating reactive oxygen species (ROS). Furthermore, DOX-MitoNVs demonstrated a significant ability to modulate the tumor immune microenvironment, thereby inducing pronounced immunogenic cell death (ICD) effects. In summary, it presents a novel therapeutic strategy utilizing DOX-MitoNVs for precise mitochondrial targeting in gliomas, enhancing drug sensitivity, inducing multiple cell death pathways, and modulating the tumor immune microenvironment to promote immunogenic cell death. STATEMENT OF SIGNIFICANCE: Mitochondrial targeting in gliomas is a promising therapeutic strategy that enhances drug sensitivity by exploiting glioma cells' mitochondrial vulnerabilities. We engineered mitochondrial membrane-based nanovesicles as artificial mitochondria for precise mitochondrial targeting of Dox. This approach facilitates selective cancer cell eradication and amplifies multiple cell death pathways alongside immunogenic chemotherapy. Notably, DOX-MitoNVs effectively cross the BBB and specifically target gliomas. By focusing on mitochondria, Dox induces apoptosis and intensifies ferroptosis through ROS generation. Additionally, DOX-MitoNVs can transform the tumor immune microenvironment, promoting ICD. Overall, DOX-MitoNVs offer a promising platform for enhanced glioma therapy.

Radiation and DNA Origami Nanotechnology: Probing Structural Integrity at the Nanoscale

DNA nanotechnology has emerged as a groundbreaking field, using DNA as a scaffold to create nanostructures with customizable properties. These DNA nanostructures hold potential across various domains, from biomedicine to studying ionizing radiation-matter interactions at the nanoscale. This review explores how the various types of radiation, covering a spectrum from electrons and photons at sub-excitation energies to ion beams with high-linear energy transfer influence the structural integrity of DNA origami nanostructures. We discuss both direct effects and those mediated by secondary species like low-energy electrons (LEEs) and reactive oxygen species (ROS). Further we discuss the possibilities for applying radiation in modulating and controlling structural changes. Based on experimental insights, we identify current challenges in characterizing the responses of DNA nanostructures to radiation and outline further areas for investigation. This review not only clarifies the complex dynamics between ionizing radiation and DNA origami but also suggests new strategies for designing DNA nanostructures optimized for applications exposed to various qualities of ionizing radiation and their resulting byproducts.

Peptide-coated DNA nanostructures as a platform for control of lysosomal function in cells

DNA nanotechnology is a rapidly growing field that provides exciting tools for biomedical applications. Targeting lysosomal functions with nanomaterials, such as DNA nanostructures (DNs), represents a rational and systematic way to control cell functionality. Here we present a versatile DNA nanostructure-based platform that can modulate a number of cellular functions depending on the concentration and surface decoration of the nanostructure. Utilizing different peptides for surface functionalization of DNs, we were able to rationally modulate lysosomal activity, which in turn translated into the control of cellular function, ranging from changes in cell morphology to modulation of immune signaling and cell death. Low concentrations of decalysine peptide-coated DNs induced lysosomal acidification, altering the metabolic activity of susceptible cells. In contrast, DNs coated with an aurein-bearing peptide promoted lysosomal alkalization, triggering STING activation. High concentrations of decalysine peptide-coated DNs caused lysosomal swelling, loss of cell-cell contacts, and morphological changes without inducing cell death. Conversely, high concentrations of aurein-coated DNs led to lysosomal rupture and mitochondrial damage, resulting in significant cytotoxicity. Our study holds promise for the rational design of a new generation of versatile DNA-based nanoplatforms that can be used in various biomedical applications, like the development of combinatorial anti-cancer platforms, efficient systems for endolysosomal escape, and nanoplatforms modulating lysosomal pH.

AI-based Prediction of Protein Corona Composition on DNA Nanostructures

DNA nanotechnology has emerged as a powerful approach to engineering biophysical tools, therapeutics, and diagnostics because it enables the construction of designer nanoscale structures with high programmability. Based on DNA base pairing rules, nanostructure size, shape, surface functionality, and structural reconfiguration can be programmed with a degree of spatial, temporal, and energetic precision that is difficult to achieve with other methods. However, the properties and structure of DNA constructs are greatly altered in vivo due to spontaneous protein adsorption from biofluids. These adsorbed proteins, referred to as the protein corona, remain challenging to control or predict, and subsequently, their functionality and fate in vivo are difficult to engineer. To address these challenges, we prepared a library of diverse DNA nanostructures and investigated the relationship between their design features and the composition of their protein corona. We identified protein characteristics important for their adsorption to DNA nanostructures and developed a machine-learning model that predicts which proteins will be enriched on a DNA nanostructure based on the DNA structures' design features and protein properties. Our work will help to understand and program the function of DNA nanostructures in vivo for biophysical and biomedical applications.

Physiological Barriers and Strategies of Lipid-Based Nanoparticles for Nucleic Acid Drug Delivery

Lipid-based nanoparticles (LBNPs) are currently the most promising vehicles for nucleic acid drug (NAD) delivery. Although their clinical applications have achieved success, the NAD delivery efficiency and safety are still unsatisfactory, which are, to a large extent, due to the existence of multi-level physiological barriers in vivo. It is important to elucidate the interactions between these barriers and LBNPs, which will guide more rational design of efficient NAD vehicles with low adverse effects and facilitate broader applications of nucleic acid therapeutics. This review describes the obstacles and challenges of biological barriers to NAD delivery at systemic, organ, sub-organ, cellular, and subcellular levels. The strategies to overcome these barriers are comprehensively reviewed, mainly including physically/chemically engineering LBNPs and directly modifying physiological barriers by auxiliary treatments. Then the potentials and challenges for successful translation of these preclinical studies into the clinic are discussed. In the end, a forward look at the strategies on manipulating protein corona (PC) is addressed, which may pull off the trick of overcoming those physiological barriers and significantly improve the efficacy and safety of LBNP-based NADs delivery.

DNA polyhedrons cube, prism, and square pyramid protect the catalytic activity of catalase: A thermodynamics and kinetics study

DNA is widely used as building block material for the construction of polyhedral nanostructures. DNA polyhedrons (DNA prism, cube, and square pyramid) are small 3D wireframed nanostructures with tunable shapes and sizes. Despite substantial progress in synthesis, the study regarding cellular responses to DNA polyhedrons is limited. Herein, the molecular interaction between DNA polyhedrons and the antioxidant enzyme, catalase has been explored. The enzymatic activity of bovine liver catalase (BLC) remains unaltered in the presence of DNA polyhedrons after 1 h of incubation. However, the activity of BLC was protected after 24 h of incubation in the presence of DNA polyhedrons as compared to the natural unfolding. The kinetics study confirmed the protective role of DNA polyhedrons on BLC with lower KM and higher catalytic efficiency. Furthermore, no profound conformational changes of BLC occur in the presence of DNA polyhedrons as observed in spectroscopic studies. From fluorescence quenching data we confirmed the binding between DNA polyhedrons and BLC. The thermodynamic parameters indicate that non-covalent bonds played a major role during the interaction of BLC with DNA polyhedrons. Moreover, the hepatic catalase activity remains unaltered in the presence of DNA polyhedrons. The cytotoxicity assay revealed that DNA polyhedrons were biocompatible in the cellular environment. The protective role of DNA polyhedrons on enzyme activity and the unaltered conformational change of protein ensures the biocompatibility of DNA polyhedrons in the cellular environment.

Structural DNA nanotechnology at the nexus of next-generation bio-applications: challenges and perspectives

DNA nanotechnology has significantly progressed in the last four decades, creating nucleic acid structures widely used in various biological applications. The structural flexibility, programmability, and multiform customization of DNA-based nanostructures make them ideal for creating structures of all sizes and shapes and multivalent drug delivery systems. Since then, DNA nanotechnology has advanced significantly, and numerous DNA nanostructures have been used in biology and other scientific disciplines. Despite the progress made in DNA nanotechnology, challenges still need to be addressed before DNA nanostructures can be widely used in biological interfaces. We can open the door for upcoming uses of DNA nanoparticles by tackling these issues and looking into new avenues. The historical development of various DNA nanomaterials has been thoroughly examined in this review, along with the underlying theoretical underpinnings, a summary of their applications in various fields, and an examination of the current roadblocks and potential future directions.

M2 Macrophage Hybrid Membrane-Camouflaged Targeted Biomimetic Nanosomes to Reprogram Inflammatory Microenvironment for Enhanced Enzyme-Thermo-Immunotherapy

Excessive inflammatory reactions caused by uric acid deposition are the key factor leading to gout. However, clinical medications cannot simultaneously remove uric acid and eliminate inflammation. An M2 macrophage-erythrocyte hybrid membrane-camouflaged biomimetic nanosized liposome (USM[H]L) is engineered to deliver targeted self-cascading bienzymes and immunomodulators to reprogram the inflammatory microenvironment in gouty rats. The cell-membrane-coating endow nanosomes with good immune escape and lysosomal escape to achieve long circulation time and intracellular retention times. After being uptaken by inflammatory cells, synergistic enzyme-thermo-immunotherapies are achieved: uricase and nanozyme degraded uric acid and hydrogen peroxide, respectively; bienzymes improved the catalytic abilities of each other; nanozyme produced photothermal effects; and methotrexate has immunomodulatory and anti-inflammatory effects. The uric acid levels markedly decrease, and ankle swelling and claw curling are effectively alleviated. The levels of inflammatory cytokines and ROS decrease, while the anti-inflammatory cytokine levels increase. Proinflammatory M1 macrophages are reprogrammed to the anti-inflammatory M2 phenotype. Notably, the IgG and IgM levels in USM[H]L-treated rats decrease substantially, while uricase-treated rats show high immunogenicity. Proteomic analysis show that there are 898 downregulated and 725 upregulated differentially expressed proteins in USM[H]L-treated rats. The protein-protein interaction network indicates that the signaling pathways include the spliceosome, ribosome, purine metabolism, etc.

Addressing the in vivo delivery of nucleic-acid nanostructure therapeutics

DNA and RNA nanostructures are being investigated as therapeutics, vaccines, and drug delivery systems. These nanostructures can be functionalized with guests ranging from small molecules to proteins with precise spatial and stoichiometric control. This has enabled new strategies to manipulate drug activity and to engineer devices with novel therapeutic functionalities. Although existing studies have offered encouraging in vitro or pre-clinical proof-of-concepts, establishing mechanisms of in vivo delivery is the new frontier for nucleic-acid nanotechnologies. In this review, we first provide a summary of existing literature on the in vivo uses of DNA and RNA nanostructures. Based on their application areas, we discuss current models of nanoparticle delivery, and thereby highlight knowledge gaps on the in vivo interactions of nucleic-acid nanostructures. Finally, we describe techniques and strategies for investigating and engineering these interactions. Together, we propose a framework to establish in vivo design principles and advance the in vivo translation of nucleic-acid nanotechnologies.

Peptide-Based Nanoparticles for Systemic Extrahepatic Delivery of Therapeutic Nucleotides

Peptide-based nanoparticles (PBN) for nucleotide complexation and targeting of extrahepatic diseases are gaining recognition as potent pharmaceutical vehicles for fine-tuned control of protein production (up- and/or down-regulation) and for gene delivery. Herein, we review the principles and mechanisms underpinning self-assembled formation of PBN, cellular uptake, endosomal release, and delivery to extrahepatic disease sites after systemic administration. Selected examples of PBN that have demonstrated recent proof of concept in disease models in vivo are summarized to offer the reader a comparative view of the field and the possibilities for clinical application.

DNA Nanomaterials-Based Platforms for Cancer Immunotherapy

The past few decades have witnessed the evolving paradigm for cancer therapy from nonspecific cytotoxic agents to selective, mechanism-based therapeutics, especially immunotherapy. In particular, the integration of nanomaterials with immunotherapy is proven to improve the therapeutic outcome and minimize off-target toxicity in the treatment. As a novel nanomaterial, DNA-based self-assemblies featuring uniform geometries, feasible modifications, programmability, surface addressability, versatility, and intrinsic biocompatibility, are extensively exploited for innovative and effective cancer immunotherapy. In this review, the successful employment of DNA nanoplatforms for cancer immunotherapy, including the delivery of immunogenic cell death inducers, adjuvants and vaccines, immune checkpoint blockers as well as the application in immune cell engineering and adoptive cell therapy is summarized. The remaining challenges and future perspectives regarding the pharmacokinetics/pharmacodynamics, in vivo fate and immunogenicity of DNA materials, and the design of intelligent DNA nanomedicine for individualized cancer immunotherapy are also discussed.

Lysosomal nanotoxicity: Impact of nanomedicines on lysosomal function

Although several nanomedicines got clinical approval over the past two decades, the clinical translation rate is relatively small so far. There are many post-surveillance withdrawals of nanomedicines caused by various safety issues. For successful clinical advancement of nanotechnology, it is of unmet need to realize cellular and molecular foundation of nanotoxicity. Current data suggest that lysosomal dysfunction caused by nanoparticles is emerging as the most common intracellular trigger of nanotoxicity. This review analyzes prospect mechanisms of lysosomal dysfunction-mediated toxicity induced by nanoparticles. We summarized and critically assessed adverse drug reactions of current clinically approved nanomedicines. Importantly, we show that physicochemical properties have great impact on nanoparticles interaction with cells, excretion route and kinetics, and subsequently on toxicity. We analyzed literature on adverse reactions of current nanomedicines and hypothesized that adverse reactions might be linked with lysosomal dysfunction caused by nanomedicines. Finally, from our analysis it becomes clear that it is unjustifiable to generalize safety and toxicity of nanoparticles, since different particles possess distinct toxicological properties. We propose that the biological mechanism of the disease progression and treatment should be central in the optimization of nanoparticle design.

Mechanical Regulation of Mitochondrial Dynamics and Function in a 3D-Engineered Liver Tumor Microenvironment

It has become evident that physical stimuli of the cellular microenvironment transmit mechanical cues regulating key cellular functions, such as proliferation, migration, and malignant transformation. Accumulating evidence suggests that tumor cells face variable mechanical stimuli that may induce metabolic rewiring of tumor cells. However, the knowledge of how tumor cells adapt metabolism to external mechanical cues is still limited. We therefore designed soft 3D collagen scaffolds mimicking a pathological mechanical environment to decipher how liver tumor cells would adapt their metabolic activity to physical stimuli of the cellular microenvironment. Here, we report that the soft 3D microenvironment upregulates the glycolysis of HepG2 and Alexander cells. Both cell lines adapt their mitochondrial activity and function under growth in the soft 3D microenvironment. Cells grown in the soft 3D microenvironment exhibit marked mitochondrial depolarization, downregulation of mitochondrially encoded cytochrome c oxidase I, and slow proliferation rate in comparison with stiff monolayer cultures. Our data reveal the coupling of liver tumor glycolysis to mechanical cues. It is proposed here that soft 3D collagen scaffolds can serve as a useful model for future studies of mechanically regulated cellular functions of various liver (potentially other tissues as well) tumor cells.

Nucleic acid nanostructures for in vivo applications: The influence of morphology on biological fate

The development of programmable biomaterials for use in nanofabrication represents a major advance for the future of biomedicine and diagnostics. Recent advances in structural nanotechnology using nucleic acids have resulted in dramatic progress in our understanding of nucleic acid-based nanostructures (NANs) for use in biological applications. As the NANs become more architecturally and functionally diverse to accommodate introduction into living systems, there is a need to understand how critical design features can be controlled to impart desired performance in vivo. In this review, we survey the range of nucleic acid materials utilized as structural building blocks (DNA, RNA, and xenonucleic acids), the diversity of geometries for nanofabrication, and the strategies to functionalize these complexes. We include an assessment of the available and emerging characterization tools used to evaluate the physical, mechanical, physiochemical, and biological properties of NANs in vitro. Finally, the current understanding of the obstacles encountered along the in vivo journey is contextualized to demonstrate how morphological features of NANs influence their biological fates. We envision that this summary will aid researchers in the designing novel NAN morphologies, guide characterization efforts, and design of experiments and spark interdisciplinary collaborations to fuel advancements in programmable platforms for biological applications.

Uptake and stability of DNA nanostructures in cells: a cross-sectional overview of the current state of the art

The physical and chemical properties of synthetic DNA have transformed this prototypical biopolymer into a versatile nanoscale building block material in the form of DNA nanotechnology. DNA nanotechnology is, in turn, providing unprecedented precision bioengineering for numerous biomedical applications at the nanoscale including next generation immune-modulatory materials, vectors for targeted delivery of nucleic acids, drugs, and contrast agents, intelligent sensors for diagnostics, and theranostics, which combines several of these functionalities into a single construct. Assembling a DNA nanostructure to be programmed with a specific number of targeting moieties on its surface to imbue it with concomitant cellular uptake and retention capabilities along with carrying a specific therapeutic dose is now eminently feasible due to the extraordinary self-assembling properties and high formation efficiency of these materials. However, what remains still only partially addressed is how exactly this class of materials is taken up into cells in both the native state and as targeted or chemically facilitated, along with how stable they are inside the cellular cytosol and other cellular organelles. In this minireview, we summarize what is currently reported in the literature about how (i) DNA nanostructures are taken up into cells along with (ii) what is understood about their subsequent stability in the complex multi-organelle environment of the cellular milieu along with biological fluids in general. This allows us to highlight the many challenges that still remain to overcome in understanding DNA nanostructure-cellular interactions in order to fully translate these exciting new materials.

Protein-Nanoparticle Interactions Govern the Interfacial Behavior of Polymeric Nanogels: Study of Protein Corona Formation at the Air/Water Interface

Biomedical applications of nanoparticles require a fundamental understanding of their interactions and behavior with biological interfaces. Protein corona formation can alter the morphology and properties of nanomaterials, and knowledge of the interfacial behavior of the complexes, using in situ analytical techniques, will impact the development of nanocarriers to maximize uptake and permeability at cellular interfaces. In this study we evaluate the interactions of acrylamide-based nanogels, with neutral, positive, and negative charges, with serum-abundant proteins albumin, fibrinogen, and immunoglobulin G. The formation of a protein corona complex between positively charged nanoparticles and albumin is characterized by dynamic light scattering, circular dichroism, and surface tensiometry; we use neutron reflectometry to resolve the complex structure at the air/water interface and demonstrate the effect of increased protein concentration on the interface. Surface tensiometry data suggest that the structure of the proteins can impact the interfacial properties of the complex formed. These results contribute to the understanding of the factors that influence the bio-nano interface, which will help to design nanomaterials with improved properties for applications in drug delivery.

Functionalizing DNA origami to investigate and interact with biological systems

DNA origami has emerged as a powerful method to generate DNA nanostructures with dynamic properties and nanoscale control. These nanostructures enable complex biophysical studies and the fabrication of next-generation therapeutic devices. For these applications, DNA origami typically needs to be functionalized with bioactive ligands and biomacromolecular cargos. Here, we review methods developed to functionalize, purify, and characterize DNA origami nanostructures. We identify remaining challenges, such as limitations in functionalization efficiency and characterization. We then discuss where researchers can contribute to further advance the fabrication of functionalized DNA origami.

The Yin and Yang of the protein corona on the delivery journey of nanoparticles

Nanoparticles-based drug delivery systems have attracted significant attention in biomedical fields because they can deliver loaded cargoes to the target site in a controlled manner. However, tremendous challenges must still be overcome to reach the expected targeting and therapeutic efficacy in vivo. These challenges mainly arise because the interaction between nanoparticles and biological systems is complex and dynamic and is influenced by the physicochemical properties of the nanoparticles and the heterogeneity of biological systems. Importantly, once the nanoparticles are injected into the blood, a protein corona will inevitably form on the surface. The protein corona creates a new biological identity which plays a vital role in mediating the bio-nano interaction and determining the ultimate results. Thus, it is essential to understand how the protein corona affects the delivery journey of nanoparticles in vivo and what we can do to exploit the protein corona for better delivery efficiency. In this review, we first summarize the fundamental impact of the protein corona on the delivery journey of nanoparticles. Next, we emphasize the strategies that have been developed for tailoring and exploiting the protein corona to improve the transportation behavior of nanoparticles in vivo. Finally, we highlight what we need to do as a next step towards better understanding and exploitation of the protein corona. We hope these insights into the "Yin and Yang" effect of the protein corona will have profound implications for understanding the role of the protein corona in a wide range of nanoparticles.

Geometry of a DNA Nanostructure Influences Its Endocytosis: Cellular Study on 2D, 3D, and in Vivo Systems

Fabrication of nanoscale DNA devices to generate 3D nano-objects with precise control of shape, size, and presentation of ligands has shown tremendous potential for therapeutic applications. The interactions between the cell membrane and different topologies of 3D DNA nanostructures are crucial for designing efficient tools for interfacing DNA devices with biological systems. The practical applications of these DNA nanocages are still limited in cellular and biological systems owing to the limited understanding of their interaction with the cell membrane and endocytic pathway. The correlation between the geometry of DNA nanostructures and their internalization efficiency remains elusive. We investigated the influence of the shape and size of 3D DNA nanostructures on their cellular internalization efficiency. We found that one particular geometry, i.e., the tetrahedral shape, is more favored over other designed geometries for their cellular uptake in 2D and 3D cell models. This is also replicable for cellular processes like cell invasion assays in a 3D spheroid model, and passing the epithelial barriers in in vivo zebrafish model systems. Our work provides detailed information for the rational design of DNA nanodevices for their upcoming biological and biomedical applications.

The interactions between DNA nanostructures and cells: A critical overview from a cell biology perspective

DNA nanotechnology has yielded remarkable advances in  composite materials with diverse applications in biomedicine. The specificity and predictability of building 3D structures at the nanometer scale make DNA nanotechnology a promising tool for uses in biosensing, drug delivery, cell modulation, and bioimaging. However, for successful translation of DNA nanostructures to real-world applications, it is crucial to understand how they interact with living cells, and the consequences of such interactions. In this review, we summarize the current state of knowledge on the interactions of DNA nanostructures with cells. We identify key challenges, from a cell biology perspective, that influence progress towards the clinical translation of DNA nanostructures. We close by providing an outlook on what questions must be addressed to accelerate the clinical translation of DNA nanostructures. STATEMENT OF SIGNIFICANCE: Self-assembled DNA nanostructures (DNs) offers unique opportunities to overcome persistent challenges in the nanobiotechnology field. However, the interactions between engineered DNs and living cells are still not well defined. Critical systematization of current cellular models and biological responses triggered by DNs is a crucial foundation for the successful clinical translation of DNA nanostructures. Moreover, such an analysis will identify the pitfalls and challenges that are present in the field, and provide a basis for overcoming those challenges.