Heavy Metal Stabilization of DNA Origami Nanostructures.

DNA origami is a powerful tool to fold 3-dimensional DNA structures with nanometer precision. Its usage, however, is limited as high ionic strength, temperatures below ∼60 °C, and pH values between 5 and 10 are required to ensure the structural integrity of DNA origami nanostructures. Here, we demonstrate a simple and effective method to stabilize DNA origami nanostructures against harsh buffer conditions using [PdCl4]2-. It provided the stabilization of different DNA origami nanostructures against mechanical compression, temperatures up to 100 °C, double-distilled water, and pH values between 4 and 12. Additionally, DNA origami superstructures and bound cargos are stabilized with yields of up to 98%. To demonstrate the general applicability of our approach, we employed our protocol with a Pd metallization procedure at elevated temperatures. In the future, we think that our method opens up new possibilities for applications of DNA origami nanostructures beyond their usual reaction conditions.

DNA Mold-Based Fabrication of Palladium Nanostructures.

DNA origami molds allow a shape-controlled growth of metallic nanoparticles. So far, this approach is limited to gold and silver. Here, the fabrication of linear palladium nanostructures with controlled lengths and patterns is demonstrated. To obtain nucleation centers for a seeded growth, a synthesis procedure of palladium nanoparticles (PdNPs) using Bis(p-sulfonatophenyl)phenylphosphine (BSPP) both as reductant and stabilizer is developed to establish an efficient functionalization protocol of the particles with single-stranded DNA. Attaching the functionalized particles to complementary DNA strands inside DNA mold cavities supports subsequently a highly specific seeded palladium deposition. This provides rod-like PdNPs with diameters of 20-35 nm of grainy morphology. Using an annealing procedure and a post-reduction step with hydrogen, homogeneous palladium nanostructures can be obtained. With the adaptation of the procedure to palladium the capabilities of the mold-based tool-box are expanded. In the future, this may allow a facile adaptation of the mold approach to less noble metals including magnetic materials such as Ni and Co.

Trapping of protein cargo molecules inside DNA origami nanocages.

The development of the DNA origami technique has directly inspired the idea of using three-dimensional DNA cages for the encapsulation and targeted delivery of drug or cargo molecules. The cages would be filled with molecules that would be released at a site of interest upon cage opening triggered by an external stimulus. Though different cage variants have been developed, efficient loading of DNA cages with freely-diffusing cargo molecules that are not attached to the DNA nanostructure and their efficient retention within the cages has not been presented. Here we address these challenges using DNA origami nanotubes formed by a double-layer of DNA helices that can be sealed with tight DNA lids at their ends. In a first step we attach DNA-conjugated cargo proteins to complementary target strands inside the DNA tubes. After tube sealing, the cargo molecules are released inside the cavity using toehold-mediated strand displacement by externally added invader strands. We show that DNA invaders are rapidly entering the cages through their DNA walls. Retention of ∼70 kDa protein cargo molecules inside the cages was, however, poor. Guided by coarse-grained simulations of the DNA cage dynamics, a tighter sealing of the DNA tubes was developed which greatly reduced the undesired escape of cargo proteins. These improved DNA nanocages allow for efficient encapsulation of medium-sized cargo molecules while remaining accessible to small molecules that can be used to trigger reactions, including a controlled release of the cargo via nanocage opening.

Sequential Pull-Down Purification of DNA Origami Superstructures.

Higher-order superstructures of individual DNA origami building blocks are frequently used in DNA nanotechnology in order to increase the structure dimensions and complexity. Here, a purification method is presented to specifically enrich a fully assembled superstructure out of an excess of substructures. The approach is based on pull-down reactions with magnetic beads, where superstructures are captured via an anchor strand on a specific terminus and then become separated from terminus-free structures. By carrying out several pull-down reactions sequentially on different termini, the full superstructures that possess all termini become finally enriched. The approach is demonstrated by purifying linear origami superstructures with up to nine monomers by two-sided pull-down reactions and a T-shaped superstructure in a three-sided pull-down reaction. In all cases, high recovery yields and purities are obtained. A crucial prerequisite for the sequential pull-down scheme is the establishment of highly specific, orthogonal sequence sets for capture, and anchor strands. It is expected that the introduced approach provides a useful and universal method to purify complex DNA origami superstructures with high specificity and yield and this way allows the massive parallel fabrication of nanostructures at high homogeneity.

Casting of Gold Nanoparticles with High Aspect Ratios inside DNA Molds.

DNA nanostructures provide a powerful platform for the programmable assembly of nanomaterials. Here this approach is extended to synthesize rod-like gold nanoparticles in a full DNA controlled manner. The approach is based on DNA molds containing elongated cavities. Gold is deposited inside the molds using a seeded-growth procedure. By carefully exploring the growth parameters it is shown that gold nanostructures with aspect ratios of up to 7 can be grown from single seeds. The highly anisotropic growth is in this case controlled only by the rather soft and porous DNA walls. The optimized seeded growth procedure provides a robust and simple routine to achieve continuous gold nanostructures using DNA templating.

Differential relationships of PTSD and childhood trauma with the course of substance use disorders.

A large body of research documents the link between Posttraumatic Stress Disorder (PTSD) and the course of Substance Use Disorders (SUD). Similar relationships have been reported between Childhood Trauma (CT) and the course of illness in patients with SUD even in the absence of PTSD, but few studies have examined differential effects of PTSD and CT (independent of PTSD) in this population. We used the International Diagnostic Checklist (IDCL) and the Posttraumatic Diagnostic Scale (PDS) to diagnose PTSD in a sample of patients with SUD (N = 459). The Childhood Trauma Questionnaire (CTQ) and the European Addiction Severity Index (EuropASI) were administered to assess childhood trauma and addiction related problems including comorbid psychopathological symptoms. The sample was divided into three groups: patients with experiences of CT and PTSD (CT-PTSD), experiences of CT without PTSD (CT-only), and neither experiences of CT nor PTSD (No trauma) to examine their differential associations with the course and severity of SUD. Patients of both the CT-PTSD (n = 95) and the CT-only group (n = 134) reported significantly higher levels of anxiety and depression as well as more suicidal thoughts and suicide attempts during their lifetime than the No trauma group (n = 209). Regarding most variables a graded association became apparent, with the highest level of symptoms in the CT-PTSD group, an intermediate level in the CT-only group and the lowest level in the No trauma group. The CT-PTSD group also differed in almost all substance use variables significantly from the No trauma group, including a younger age at first use of alcohol and cannabis, more cannabis use in the last month, and more lifetime drug overdoses. Our results confirm the relationships of both CT and PTSD with psychiatric symptoms in patients with SUD. Thus, it seems important to include both domains into the routine assessment of SUD patients. Specific treatments for comorbid PTSD but also for other consequences of childhood trauma should be integrated into SUD treatment programs.

["Nicht von schlechten Eltern - NischE": A Family Orientated Collaborative Care Approach to Support Children in Families with Mentally Ill Parents]. / Nicht von schlechten Eltern ­ NischE: Ein Brückenkonzept familienorientierter Versorgung von Kindern mit psychisch oder suchtbelasteten Eltern.

"Nicht von schlechten Eltern - NischE": A Family Orientated Collaborative Care Approach to Support Children in Families with Mentally Ill Parents The present work describes the setting- and multi-professional offer "NischE" in Gütersloh, a systemic approach for the care of children and their mentally ill parents. Children of mentally ill parents are a special risk group for developing their own mental illness. The aim of the collaborative care model between child and adolescent psychiatry, youth services and adult psychiatry is to enable affected families in terms of family-focused practice a low threshold access to different services. For this purpose, two positions have been created to advise the affected families and support access to the help system in the sense of a systemic case management in a project. The article describes the background and the need for the development of the offer, the current scientific knowledge base on the subject and illustrates the procedure using a case study from practice.

Childhood trauma and dissociation in patients with alcohol dependence, drug dependence, or both-A multi-center study.

BACKGROUND: The aims of this study were to examine the level of dissociative symptoms in patients with different substance related disorders (alcohol dependence, drug dependence, and combined alcohol and drug dependence), and to investigate the influence of potentially traumatic events in childhood, age, gender, and posttraumatic stress disorder on the relationship between dissociative symptoms and type of substance abuse. METHODS: Of the 459 participants (59.7% male) 182 (39.7%) were alcohol-dependent (A), 154 (33.6%) were drug-dependent (D), and 123 (26.8%) were dependent on both, alcohol and drugs (AD) based on the DSM-IV criteria for a current diagnosis. Participants completed the Childhood Trauma Questionnaire (CTQ) and the Dissociative Experiences Scale (DES). The International Diagnostics Checklist (IDCL) was administered to diagnose PTSD. RESULTS: Higher levels of dissociation were observed in patients with drug dependence as compared to patients with mere alcohol dependence (mean DES group A: 9.9+/-8.8; group D: 12.9+/-11.7; group AD: 15.1+/-11.3). However, when severity of potentially traumatic events in childhood, PTSD, age and gender were included in the analysis, the influence of the type of substance abuse did not prove to be statistically significant. The variable most strongly related to dissociative symptoms was severity of potentially traumatic events in childhood, in particular emotional abuse, even after controlling for PTSD and other potential confounders. CONCLUSIONS: It seems appropriate to screen SUD patients for dissociative symptoms, especially those with a more complex risk profile including (additional) drug abuse, female gender, younger age and most importantly a history of childhood trauma.

Trauma and PTSD in patients with alcohol, drug, or dual dependence: a multi-center study.

BACKGROUND: We investigated (1) the prevalence of posttraumatic stress disorder (PTSD) in treatment-seeking subjects with substance use dependence (SUD), (2) the association between comorbid PTSD and the severity and course of addiction and psychopathology, and (3) this association in patients with subsyndromal PTSD, and in trauma exposure without PTSD. METHODS: In this cross-sectional study, 459 subjects in 14 German addiction treatment centers participated with alcohol-dependence (A) in 39.7%, drug-dependence (D) in 33.6%, or both (AD) 26.8%. The diagnostic measures included the International Diagnostic Checklists (IDCL), Posttraumatic Diagnostic Scale (PDS), Addiction Severity Index (ASI), and the Brief Psychiatric Rating Scale (BPRS). Associations between independent characteristics and outcomes were analysed by univariate and multivariate statistics. RESULTS: 25.3% of the subjects had PTSD confirmed by both IDCL and PDS with higher rates in the AD (34.1%) and D (29.9%) groups compared with group A (15.4%, p < 0.001). In 22.8%, PTSD was subsyndromal (either IDCL or PDS positive) without significant differences between SUD groups, and 18.3% met PTSD trauma criteria A without PTSD (exposure). After controlling for SUD and gender, trauma subgroups significantly differed regarding the onset of alcohol-related symptoms (p < 0.02), numbers of previous admissions (p < 0.03), severity of SUD (p < 0.001), current craving (p < 0.02), and psychopathology (p < 0.001). We observed the worst outcome in PTSD, while trauma exposure had no effects. CONCLUSIONS: The prevalence of PTSD is higher in drug than in alcohol dependence. The more strictly PTSD is diagnosed (by interviewer and questionnaire) the more clearly are associations with characteristics of SUD. PTSD seems to be an independent risk factor for an unfavorable outcome of SUD.