Ionic Strength-Mediated "DNA Corona Defects" for Efficient Arrangement of Single-Walled Carbon Nanotubes.

Single-stranded DNA oligonucleotides wrapping on the surface of single-walled carbon nanotubes (SWCNTs), described as DNA corona, are often used as a dispersing agent for SWCNTs. The uneven distribution of DNA corona along SWCNTs is related to the photoelectric properties and the surface activity of SWCNTs. An ionic strength-mediated "DNA corona defects" (DCDs) strategy is proposed to acquire an exposed surface of SWCNTs (accessible surface) as large as possible while maintaining good dispersibility via modulating the conformation of DNA corona. By adjusting the solution ionic strength, the DNA corona phase transitioned from an even-distributed and loose conformation to a locally compact conformation. The resulting enlarged exposed surface of SWCNTs is called DCDs, which provide active sites for molecular adsorption. This strategy is applied for the arrangement of SWCNTs on DNA origami. SWCNTs with ≈11 nm DCD, providing enough space for the adsorption of "capture ssDNA" (≈7 nm width required for 24-nt) extended from DNA origami structures are fabricated. The DCD strategy has potential applications in SWCNT-based optoelectronic devices.

The controllable patterning of tannic acid on DNA origami.

Tannic acid-based patterning is crucial for its applications in bioengineering, including multifunctional coatings, biosensors, and biochips. However, tannic acid (TA) patterning is challenging owing to the rapid polymerization kinetics of tannins and their strong adhesion towards most surfaces or objects. Herein, we report a strategy for controllable TA nanopatterning based on DNA origami templates. Protruding clustered ssDNA (pcDNA) from DNA origami tiles served as indexes for the selective deposition of TA due to the high flexibility of ssDNA and exposed aromatic bases, which provide active sites for TA-DNA interactions. Next, by exploiting the pH-sensitive degradation of TA polymers, controllable 'erasing' and 'rewriting' of TA nanopatterns were performed. Finally, combining the high adhesion and selective deposition, the TA polymers as a glue modified on the edges of origami tiles directed the reversible association/disassociation of origami multimers. Our strategy provides a simple approach for the controllable nanopatterning of TA, enabling its unique properties to tailor surface patterns for applications in materials science and biomedicine.

Surface Engineering of Lipid Vesicles Based on DNA Nanotechnology.

Lipid vesicle research is of great significance in the field of biomedicine and great progress has been made in recent years, in which the surface engineering on lipid membranes plays an important role. By introducing new active sites on membrane surface, the physicochemical properties of vesicles are regulated and the biological functions are extended. DNA nanotechnology is an excellent tool for surface engineering of vesicles and has attracted more and more attention. In this Review, the interaction between DNA and lipid membrane is presented. Subsequently, recent advances in the applications of vesicle-surface-engineering based on DNA nanotechnology are highlighted. DNA nanostructures are used to mimic membrane proteins in the system of artificial liposome vesicles. Surface-engineered extracellular vesicles (EVs) based on DNA nanotechnology are applied to achieve non-invasive early screening of diseases with high sensitivity and precision. Finally, challenges and prospects for future development in this field are discussed.

Effect of the stiffness of one-layer protein-based microcapsules on dendritic cell uptake and endocytic mechanism.

Microcapsules are one of the most promising microscale drug carriers due to their facile fabrication, excellent deformability, and high efficacy in drug storage and delivery. Understanding the effects of their physicochemical properties (size, shape, rigidity, charge, surface chemistry, etc.) on both in vitro and in vivo performance is not only highly significant and interesting but also very challenging. Stiffness, an important design parameter, has been extensively explored in recent years, but how the rigidity of particles influences cellular internalization and uptake mechanisms remains controversial. Here, one-layered lysozyme-based microcapsules with well-controlled stiffness (modulus ranging from 3.49 ± 0.18 MPa to 26.14 ± 1.09 MPa) were prepared and used to investigate the effect of stiffness on the uptake process in dendritic cells and the underlying mechanism. The cellular uptake process and endocytic mechanism were investigated with laser scanning confocal microscopy, mechanism inhibitors, and pathway-specific antibody staining. Our data demonstrated that the stiffness of protein-based microcapsules could be a strong regulator of intracellular uptake and endocytic kinetics but had no obvious effect on the endocytic mechanism. We believe our results will provide a basic understanding of the intracellular uptake process of microcapsules and the endocytic mechanism and inspire strategies for the further design of potential drug delivery microcarriers.

One-Pot Generating Subunit Vaccine with High Encapsulating Efficiency and Fast Lysosome Escape for Potent Cellular Immune Response.

Utilizing nanoparticles to deliver subunit vaccine is considered to be a promising strategy to improve immune response. However, currently reported systems suffered from one or more points, for example, delicate design on molecular structures and elaborate synthesis process, low antigen and/or adjuvant encapsulation efficiency, involvement of toxic materials, and denaturing of bioactivity of antigen and/or adjuvant. To address these issues, here, for the first time, we developed a one-pot method to produce a subunit vaccine by using hexa-histidine metal assembly (HmA) to codeliver tumor-associated antigens (GP100, a peptide KTWGQYWQV) and adjuvant (CpG). The generation of subunit vaccines was detailedly characterized by various techniques, including dynamic scatter, scanning electron microscopy, transmission electron microscopy, UV-visible spectroscopy, agarose gel electrophoresis, etc. HmA displayed high efficiency on encapsulating both subunits (GP100 and CpG) under mild conditions, and the generated subunit vaccine showed a pH-dependent release profile of loaded subunits. In the cellular tests, these subunit vaccines behaved with a quick endocytosis into immune cells and a fast endo/lysosomes escape, inducing maturation of antigen presentative cells and stimulating a potent cellular immune response. These results suggested that HmA is a robust platform for fabricating subunit vaccine, with immense potential for the immunotherapy of various diseases.

Hexahistidine-Metal Assemblies: A Facile and Effective Codelivery System of Subunit Vaccines for Potent Humoral and Cellular Immune Responses.

Fully effective vaccines must induce both potent humoral and cellular immunities. Nanoparticles coencapsulating antigens and adjuvants have shown promising advantages as subunit vaccines in many aspects. However, the low loading efficiency and complicated synthesis process of these nanomaterials need to be improved. Here, we utilized hexahistidine (His6)-metal assembly (HmA) particles as carriers to codeliver ovalbumin peptides and cytosine-phosphate-guanine oligodeoxynucleotides (CpG ODNs). We found that antigen/adjuvant-carrying HmA can efficiently enter into antigen-presenting cells and help the antigens escape from lysosomes to induce the maturation of these cells in vitro, characterized by increasing expression levels of costimulatory molecules and cytokines. More importantly, the vaccines with high biocompatibility can elicit strong humoral and cellular immunities by improving secretion of specific antibodies and cytokines, enhancing activation of DCs and T cells in vivo. Our results suggest that HmA provides a new approach for subunit vaccines by codelivery of antigens and adjuvants.

Evaluation of His6-Metal Assemblies as a Drug Delivery Vehicle in the Treatment of Anterior Segment Disease Using a Corneal Inflammation Model.

Keratitis is a common ophthalmological disease and also a common cause of blindness (second only to cataracts). This disease is routinely treated by topical administration of dexamethasone sodium phosphate (Dexp). However, due to the presence of anatomical and physiological barriers, frequent administration is needed, often resulting in poor patient compliance and diverse side effects. In this work, Dexp was in situ encapsulated into a His6-metal assembly (HmA) to generate Dexp@HmA, which was utilized in the ocular delivery of Dexp. The physicochemical properties of HmA and Dexp@HmA particles were characterized in detail using various techniques such as dynamic light scattering (DLS), scanning electron microscopy (SEM), and UV-vis spectroscopy. Compared to commercial Eudragi and reported PLGA nanoparticles, HmA showed higher encapsulation efficiency (EE%) and higher loading capacity (LC wt %) of Dexp. Dexp@HmA displayed pH-dependent release; after 33 days at pH 5.8, 6.5, and 7.2, 100%, 65%, and 42% of Dexp, respectively, had been released. In addition, HmA and Dexp@HmA showed low cytotoxicity to macrophages and to all common ocular cell types tested. The effect of Dexp@HmA on corneal inflammation was evaluated using in vitro and in vivo models. Our results demonstrate that Dexp@HmA is much superior to free Dexp in both in vitro and in vivo models. These positive results suggest that HmA may represent a promising candidate nanocarrier for the treatment of various diseases of the anterior segment of the eye.

A Strategy to Fight against Triple-Negative Breast Cancer: pH-Responsive Hexahistidine-Metal Assemblies with High-Payload Drugs.

Triple-negative breast cancer (TNBC), an aggressive subtype of breast cancer, is difficult to be targeted therapeutically due to negative expression of the bioreceptor, which leads to the poorest overall four-year survival rate among all cancer subtypes. We proposed that the nanomedicine featuring high payload and pH-responsive release of the loaded drugs could assist the TNBC treatment. In the present study, the His6-metal assemblies (HmA) were employed to encapsulate the doxorubicin (Dox), and the effect of HmA loaded with Dox (HmA@Dox) on treating TNBC was evaluated in vitro and in vivo. We found that the participation of Dox in the formation of HmA leads to high loading efficiency (99.4% for concentration ≤ 1 mg/mL) and the loading capacity (50.7% for concentration ≥ 10 mg/mL) of Dox encapsulated into HmA. HmA@Dox exhibited a narrow size distribution on the nanoscale, a pH-responsive release of loaded Dox, a quick endocytosis process, and fast lysosome escape. Most importantly, the HmA@Dox showed high efficacy in killing various breast cancer cells (MCF-7, MDA-MB-231, and MDA-MB-453) in vitro and depressing the development of TNBC in vivo. Our results demonstrated that such a strategy for designing a nanomedicine with high payload and responsive release of drugs to the environment around the tumor was of great importance to treat TNBC.

Shape Effect of Nanoparticles on Tumor Penetration in Monolayers Versus Spheroids.

The physical properties of nanoparticles (NPs), such as size, surface chemistry, elasticity, and shape, have exerted a profound influence on tumor penetration. However, the effect of shape on cellular uptake and tumor penetration is still unclear because of the different chemical compositions and shapes of tested particles and the use of inapposite cellular models. To discover the effect of NP shapes on cellular uptake and tumor penetration and bridge the gap between models in vivo and in vitro, elongated polystyrene (PS) NPs with a fixed volume, an identical chemical composition, and the same zeta potential, but with different aspect ratios (ARs), were generated. The physical properties, cellular uptake, tumor penetration, and corresponding mechanisms of these NPs were thoroughly investigated. We discovered that the elongated PS particles with higher ARs had lower uptake rates in the 2-dimensional cell monolayer culture model in vitro, but they showed optimal ARs in the evaluated three-dimensional spheroid model. Although the elongated PS particles had a similar tumor penetration mechanism (mainly through extracellular pathways), the percentage of penetration using these mechanisms was strongly dependent on the ARs. As an alternative model for studies in vivo, spheroids were used instead of the cell monolayer for the development of drug delivery systems. In addition, the physicochemical properties of NPs must be delicately balanced and adjusted to achieve the best therapeutic outcomes.

Hexahistidine-metal assemblies: A promising drug delivery system.

It is of considerable interest to construct an ideal drug delivery system (i.e., high drug payload, minimal cytotoxicity, rapid endocytosis, and lysosomal escape) under mild conditions for disease treatment, tissue engineering, bioimaging, etc. Inspired by the coordinative interactions between histidine and metal ions, we present the facile synthesis of hexahistidine (His6)-metal assembly (HmA) particles under mild conditions for the first time. The HmA particles presented a high loading capacity, a wide variety of loadable drugs, minimal cytotoxicity, quick internalization, the ability to bypass the lysosomes, and rapid intracellular drug release. In addition, HmA encapsulation largely improved the antitumor ability of camptothecin (CPT) relative to free CPT. By capitalizing on these promising features in drug delivery, HmA will have great potential in various biomedical fields. STATEMENT OF SIGNIFICANCE: It is of considerable interest to construct an ideal drug delivery system (i.e., high drug payload, minimal cytotoxicity, rapid endocytosis, and lysosomal escape) under mild conditions. Inspired by the coordinative interactions between histidine and metal ions, we present for the first time the facile synthesis of Hexahistidine (His6)-metal assembly (HmA) particles under mild conditions. The HmA particles exhibited a high loading capacity, a wide variety of loadable drugs, minimal cytotoxicity, quick internalization, the ability to bypass the lysosomes, and rapid intracellular drug release. By capitalizing on these promising features in drug delivery, HmA will have great potential in various biomedical fields.

Designing nanoparticles with improved tumor penetration: surface properties from the molecular architecture viewpoint.

Cancer is the second most common cause of death, and nanomedicine is regarded as one of the strategies that may revolutionize cancer treatments. However, the tumor microenvironment (e.g., increased interstitial fluid pressure and dense extracellular matrix) hinders the penetration of nanomedicine into tumor cells, which leads to a short acting time and low drug concentration with tumors, eventually leading to a high recurrence rate and therapeutic failure in clinics. Developing a delivery system with deep penetration ability into the tumor has always been pursued and highly desirable for cancer treatments. Inspired by the high cellular uptake efficiency of enveloped viruses with rough and nanoscale surfaces, we constructed polystyrene nanoparticles (NPs) with similar sizes and charges, but with different surface topologies at the molecular level, by conjugating poly(propylene imine) (PPI) dendrimers with different generations onto the NPs. We found that subtle changes made to the surficial chemical properties led to changes in surface roughness and wettability, which considerably influenced the cellular internalization, endocytosis mechanism, and penetration into the tumor model both in vitro and in vivo. This will shed light on the future design of drug delivery vehicles and facilitate understanding the interactions between NP surfaces and cells, as well as tumor penetration.