Programming the morphology of DNA origami crystals by magnesium ion strength.

Harnessing the programmable nature of DNA origami for controlling structural features in crystalline materials affords opportunities to bring crystal engineering to a remarkable level. However, the challenge of crystallizing a single type of DNA origami unit into varied structural outcomes remains, given the requirement for specific DNA designs for each targeted structure. Here, we show that crystals with distinct equilibrium phases and shapes can be realized using a single DNA origami morphology with an allosteric factor to modulate the binding coordination. As a result, origami crystals undergo phase transitions from a simple cubic lattice to a simple hexagonal (SH) lattice and eventually to a face-centered cubic (FCC) lattice. After selectively removing internal nanoparticles from DNA origami building blocks, the body-centered tetragonal and chalcopyrite lattice are derived from the SH and FCC lattices, respectively, revealing another phase transition involving crystal system conversions. The rich phase space was realized through the de novo synthesis of crystals under varying solution environments, followed by the individual characterizations of the resulting products. Such phase transitions can lead to associated transitions in the shape of the resulting products. Hexagonal prism crystals, crystals characterized by triangular facets, and twinned crystals are observed to form from SH and FCC systems, which have not previously been experimentally realized by DNA origami crystallization. These findings open a promising pathway toward accessing a rich phase space with a single type of building block and wielding other instructions as tools to develop crystalline materials with tunable properties.

Dynamically Reconfigurable DNA Origami Crystals Driven by a Designated Path Diagram.

Constructing adaptable and switchable crystal structures renders it possible to dynamically control the properties and functions of adaptive materials, thereby expanding the potential application of these structures in fields such as optics, biology, and catalysis. Recently, researchers have developed various dynamic crystals possessing phase transition abilities. However, manufacturing switchable crystals with multiple-phase-transition ability by integrating various responsive behaviors into different dimensions of a single lattice remains considerably challenging. Herein, we built a set of dynamically reconfigurable DNA origami crystals by orthogonally integrating multiple dynamic effectors into the prescribed dimensions of the octahedral DNA origami frames. Further, we independently manipulated and logically combined the dynamic behaviors of the effectors in different dimensions. The initial mother phase and three derived daughter phases were interconnected into a path diagram by six elementary paths. Furthermore, these paths could be superimposed under multiple stimulus instructions by design to obtain the desired intricate transition routes. Moreover, finer manipulations were also applied to these paths to obtain extra new phase stations for the path diagram. To conveniently detect these phase transitions, a color-based visualization strategy was developed that converted the microscopic symmetry transformation of the lattices into macroscopic color changes that could be observed via a fluorescence microscope. Hence, this strategy lays the foundation for artificially constructing biomimetic functional crystals.

Two-Stage Assembly of Nanoparticle Superlattices with Multiscale Organization.

Self-assembly processes, while promising for enabling the fabrication of complexly organized nanomaterials from nanoparticles, are often limited in creating structures with multiscale order. These limitations are due to difficulties in practically realizing the assembly processes required to achieve such complex organizations. For a long time, a hierarchical assembly attracted interest as a potentially powerful approach. However, due to the experimental limitations, intermediate-level structures are often heterogeneous in composition and structure, which significantly impacts the formation of large-scale organizations. Here, we introduce a two-stage assembly strategy: DNA origami frames scaffold a coordination of nanoparticles into designed 3D nanoclusters, and then these clusters are assembled into ordered lattices whose types are determined by the clusters' valence. Through modulating the nanocluster architectures and intercluster bindings, we demonstrate the successful formation of complexly organized nanoparticle crystals. The presented two-stage assembly method provides a powerful fabrication strategy for creating nanoparticle superlattices with prescribed unit cells.

DNA origami single crystals with Wulff shapes.

DNA origami technology has proven to be an excellent tool for precisely manipulating molecules and colloidal elements in a three-dimensional manner. However, fabrication of single crystals with well-defined facets from highly programmable, complex DNA origami units is a great challenge. Here, we report the successful fabrication of DNA origami single crystals with Wulff shapes and high yield. By regulating the symmetries and binding modes of the DNA origami building blocks, the crystalline shapes can be designed and well-controlled. The single crystals are then used to induce precise growth of an ultrathin layer of silica on the edges, resulting in mechanically reinforced silica-DNA hybrid structures that preserve the details of the single crystals without distortion. The silica-infused microcrystals can be directly observed in the dry state, which allows meticulous analysis of the crystal facets and tomographic 3D reconstruction of the single crystals by high-resolution electron microscopy.

Environment-Resistant DNA Origami Crystals Bridged by Rigid DNA Rods with Adjustable Unit Cells.

The crystallization methodology of DNA origami frames has found salient utility in large-scalely integrating multifarious functional components following organized arrangements, thus opening up the possibilities for optical, biological, and other interdisciplinary applications. However, the single strand-dominated spacing region between adjacent DNA origami units has extremely restricted the adjustment of DNA origami separations, leading the soft crystals susceptible to environmental influences. Herein, we developed a cocrystallization pathway by incorporating rigid DNA rods into a DNA origami assembly system to achieve mutually ordered bridging on a three-dimensional scale. The intervention of DNA rods significantly improved the rigidity and crushing resistance of entire cocrystals and rendered DNA origami units exhibiting different spacing distances within the obtained crystal phase when varying DNA rod structures artificially. Such a tuning strategy that uses DNA rods as allosteric factors would provide a rational method for accessing diverse crystalline states and even modulating the tailorable properties of materials on demand.

DNA origami: an outstanding platform for functions in nanophotonics and cancer therapy.

Due to the proposal and evolution of the DNA origami technique over the past decade, DNA molecules have been utilized as building blocks for the precise construction of nanoscale architectures. Benefiting from the superior programmability of DNA molecules, the sequence-dependent recognition mechanism and robust complementation among DNA strands make it possible to customize almost arbitrary structures. Such an assembly strategy bypasses some of the limits of conventional fabrication methods; the fabrication accuracy and complexity of the target product are unprecedentedly promoted as well. Furthermore, due to the spatial addressability of the final products, nanostructures assembled through the DNA origami technique can also serve as a versatile platform for the spatial positioning of functional elements, represented by colloidal nanoparticles (NPs). The subsequent fabrication of heterogeneous functional nanoarchitectures is realized via modifying colloidal NPs with DNA strands and manipulating them to anchor into DNA origami templates. This has given rise to investigations of their novel properties in nanophotonics and therapeutic effects towards some diseases. In this review, we survey the crucial progress in the development of DNA origami design, assembly and structural analysis and summarize available applications in nanophotonics and cancer therapy based on the object-dressed DNA origami complex. Moreover, we elucidate the development of this field and discuss the potential directions of this kind of application-oriented nanomanufacturing.

Programmable Cocrystallization of DNA Origami Shapes.

Assembly of distinct types of species, particularly possessing anisotropic configurations, is the premise to broaden structural diversity and explore materials' collective properties. However, it remains a great challenge to programmably cocrystallize manifold anisotropic nanoparticles with the desired assembly mode, because it requires not only the complementarity of both sizes and shapes but also the control over their directional interactions. Here, by introducing DNA origami technique into lattice engineering, we synthesize two types of DNA nano-objects with different symmetries and program the heterogeneous functional patches precisely on their surfaces with nanometer-level precision, which could guide further assembly of these nano-objects. We show that these anisotropic DNA nano-objects could be cocrystallized along specified modes via modulating the combination of surface patches. The highly ordered DNA crystals were thoroughly evidenced by techniques including small-angle X-ray scattering and electron microscopy after careful encapsulation of a thin layer of silica on these DNA nano-objects. Our strategy endows distinct shapes of organic DNA origami structures with regulation features to control the sophisticated modes of cocrystallization of these diverse components, laying a foundation for designing and fabricating customized three-dimensional structures with given optical and mechanical properties.

Stepwise assembly of nanoclusters guided by DNA origami frames with high-throughput.

We contrive two strategies to assemble well-defined nanoclusters with high-throughput guided by DNA origami frames either by (1) introducing a micro-sized surface to fabricate patchy particles for binding with DNA structures or (2) restricting the assembly process of free nanoparticles and DNA origami frames on the fixed sites. Both the strategies can omit the process of gel purification of the final products.

Programmable Assembly of Nano-architectures through Designing Anisotropic DNA Origami Patches.

Programmable assembly of nanoparticles (NPs) into well-defined architectures has attracted attention because of tailored properties resulting from coupling effects. However, general and precise approaches to control binding modes between NPs remain a challenge owing to the difficulty in manipulating the accurate positions of the functional patches on the surface of NPs. Here, a strategy is developed to encage spherical NPs into pre-designed octahedral DNA origami frames (DOFs) through DNA base-pairings. The DOFs logically define the arrangements of functional patches in three dimensions, owing to the programmability of DNA hybridization, and thus control the binding modes of the caged nanoparticle with designed anisotropy. Applying the node-and-spacer approach that was widely used in crystal engineering to design coordination polymers, patchy NPs could be rationally designed with lower symmetry encoded to assemble a series of nano-architectures with high-order geometries.

Oral sildenafil treatment for Eisenmenger syndrome: a prospective, open-label, multicentre study.

BACKGROUND: Although sildenafil has been shown to be safe and effective in idiopathic pulmonary arterial hypertension (PAH) and PAH related to connective tissue disease, its effects in Eisenmenger syndrome are less clear. OBJECTIVE: To investigate whether long-term treatment (12 months) with the phosphodiesterase type 5 inhibitor sildenafil improves clinical and haemodynamic parameters in patients with Eisenmenger syndrome. DESIGN: Prospective, open-label, multicentre study. SETTING: Four pulmonary hypertension centres in China. PATIENTS: 84 Eisenmenger syndrome functional class II-IV patients. INTERVENTIONS: Oral sildenafil 20 mg orally three times a day. OUTCOME MEASURES: 6-min walk distance (6MWD) test, resting systemic arterial blood oxygen saturation (SaO(2)) in room air, haemodynamic parameters assessed by right heart catheterisation, safety and tolerability. RESULTS: The overall treatment effects at 12 months versus baseline (mean changes with 95% CIs) were 56 m increase (42 to 69, p<0.0001) in 6MWD, and 2.4% increase (1.8% to 2.9%, p<0.0001) in resting room air SaO(2). Improvements were also seen in mean pulmonary arterial pressure and pulmonary vascular resistance index (-4.7 mm Hg (-7.5 to -1.9), p=0.001; and -474 dyn×s×cm(-5)×m(2) (-634 to -314), p<0.0001, respectively). Sildenafil was well tolerated. Most adverse events were mild and transient, and occurred in the first 2 weeks of treatment. CONCLUSIONS: Twelve months of oral sildenafil treatment was well tolerated and appeared to improve exercise capacity, systemic arterial oxygen saturation and haemodynamic parameters in patients with Eisenmenger syndrome.

[The efficacy and safety of bosentan therapy for Chinese patients with idiopathic pulmonary arterial hypertension: an open-label, prospective multicenter study].

OBJECTIVE: To investigate the efficacy, safety and tolerance of bosentan, a dual endothelin receptor antagonist, in Chinese patients with idiopathic pulmonary arterial hypertension (IPAH). METHODS: Totally 79 IPAH patients (hemodynamic criteria confirmed by right heart catheterization) were included in this open-label, prospective multicenter study. Patients received 62.5 mg of bosentan twice daily for the first 4 weeks, and then up-titrated to 125 mg twice daily for another 12 weeks. The primary end point was the change in exercise capacity showed by six-minute walk distance (6MWD) from baseline to 16 weeks. Secondary end points included the change in World Health Organization (WHO) functional class, Borg dyspnoea scale and systolic pulmonary artery pressure measured by echocardiography. RESULTS: The 6MWD increased from (343.7 ± 93.7) meters at baseline to (397.5 ± 104.4) meters after 16 weeks (P < 0.01), WHO functional class and Borg dyspnoea scale were also significantly improved after 16 weeks therapy compared to baseline levels (all P < 0.01). Furthermore, the systolic pulmonary artery pressure was significantly decreased from (97.8 ± 25.2) mm Hg (1 mm Hg = 0.133 kPa) to (92.8 ± 29.5) mm Hg (P < 0.05) after 16 weeks bosentan treatment. There was no patient withdrawal from this study for safety consideration. CONCLUSION: Bosentan therapy is well tolerated and can improve the exercise capacity and WHO functional class in Chinese IPAH patients.

Survival of Chinese patients with pulmonary arterial hypertension in the modern treatment era.

BACKGROUND: In a previous study of Chinese patients with idiopathic pulmonary arterial hypertension (IPAH) in the nontargeted therapy era (defined as the time before 2006 when new pulmonary arterial hypertension-specific drugs were not available in China), we reported 1- and 3-year survival estimates of only 68% and 39%, respectively. However, it is not yet known whether the survival of patients with pulmonary arterial hypertension is improved in the modern treatment era (defined in China as after 2006). METHODS: A retrospective cohort study was undertaken in 276 consecutive patients with newly diagnosed incident IPAH and connective tissue disease-related pulmonary arterial hypertension (CTDPAH) who were referred between 2007 and 2009. Baseline characteristics and survival rates in the two groups were compared. RESULTS: The 1- and 3-year survival estimates were 92.1% and 75.1%, respectively, in patients with IPAH, and 85.4% and 53.6%, respectively, in patients with CTDPAH. Patients with CTDPAH had a significantly lower mean pulmonary artery pressure, more pericardial effusion, and more severe impairment of the diffusion capacity of the lung for carbon monoxide than patients with IPAH. A diagnosis of CTDPAH, World Health Organization functional class III or IV, single-breath diffusion capacity of the lung for carbon monoxide < 80% predicted, and the presence of pericardial effusion were independent predictors of mortality. The 1- and 3-year survival rates of male patients were 93.5% and 77.5%, respectively, in those with IPAH, and 71.1% and 47.4%, respectively, in those with CTDPAH. CONCLUSIONS: The survival rates of patients with pulmonary arterial hypertension have improved in China in the modern treatment era, despite the high costs of treatment and financial constraints. However, the survival rates of patients with CTDPAH are inferior to those of patients with IPAH. Our study also indicates poorer survival rates in male patients with CTDPAH.

[Diagnosis value of electrocardiogram in patients with pulmonary artery hypertension].

OBJECTIVES: To analyze the diagnostic value of electrocardiogram (ECG) in patients with pulmonary artery hypertension (PAH) confirmed by right-heart catheterization (RHC). METHODS: A total of 64 patients with suspected PAH [sPAP > or = 36 mm Hg (1 mm Hg = 0.133 kPa) estimated by echocardiography] were enrolled in this study. All patients were examined by 12-lead ECG within half an hour before RHC. RESULTS: PAH was excluded in 26 patients and confirmed in 38 patients. ECG analysis showed that S amplitude > 0.21 mV in lead I, QRS axis > 87 degrees , R(V1) + S(V5) > 0.76 mV were good parameters for diagnosing PAH with sensibility and specificity of 89%, 81%; 86%, 92%; 84%, 83%, respectively. QRS axis was positively correlated with mean pulmonary artery pressure (mPAP) (r = 0.75, P < 0.001), R(V1) + S(V5) was positively correlated with pulmonary vascular resistance (PVR) (r = 0.74, P < 0.001), R(V1) + S(V5) and S amplitude in lead I was negatively correlated with cardiac index (CI) (r = -0.62, P < 0.001). CONCLUSION: ECG combined with echocardiography are adequate screening tools to rule out the presence of PAH. QRS axis, R(V1) + S(V5) and S amplitude in lead I were significantly correlated with hemodynamic parameters derived from RHC in PAH patients.

[Clinical efficacy of intravenous L-carnitine in patients with right-sided heart failure induced by pulmonary arterial hypertension].

OBJECTIVE: To investigate the efficacy of L-carnitine in patients with right-sided heart failure induced by pulmonary arterial hypertension (PAH). METHODS: A total of 66 pulmonary arterial hypertension patients (14 idiopathic, 36 congenital heart disease associated and 16 connective-tissue disease associated PAH, WHO heart functional class III, n = 38 or IV, n = 28) were enrolled in this study and divided into control group (26 cases) and L-carnitine group (40 cases). All patients received conventional treatment according to guideline for treatment of right-sided heart failure. The patients in L-carnitine group received 5 g/d L-carnitine intravenously for seven days. Six-minute walking distance, WHO heart functional class, physical examination, and serum markers were evaluated at baseline and 7 days after enrollment. RESULTS: Compared to the baseline, six-minute walking distance was significantly increased (75 m vs. 45 m, P < 0.05), WHO heart functional class significantly improved (improved 2 classes in 16 patients, improved 1 class in 13, no improved in 6, worsen in 5 vs. 3, 8, 9, 6 respectively in the control, P = 0.04), BNP level significant decreased (58.16 ng/L vs. 33.29 ng/L, P = 0.01) and systolic blood pressure significantly increased [8.1 mm Hg vs. 2.4 mm Hg (1 mm Hg = 0.133 kPa), P = 0.03] in L-carnitine group compared with those in control group. No patient was withdrawn from this study for safety reasons. CONCLUSIONS: L-carnitine could improve short-term exercise capacity and WHO heart functional class in right-sided heart failure patients induced by PAH.