Complex multicomponent patterns rendered on a 3D DNA-barrel pegboard.

DNA origami, in which a long scaffold strand is assembled with a many short staple strands into parallel arrays of double helices, has proven a powerful method for custom nanofabrication. However, currently the design and optimization of custom 3D DNA-origami shapes is a barrier to rapid application to new areas. Here we introduce a modular barrel architecture, and demonstrate hierarchical assembly of a 100 megadalton DNA-origami barrel of ~90 nm diameter and ~250 nm height, that provides a rhombic-lattice canvas of a thousand pixels each, with pitch of ~8 nm, on its inner and outer surfaces.

Lipid Membrane Encapsulation of a 3D DNA Nano Octahedron.

Structural DNA nanotechnology methods such as DNA origami allow for the synthesis of highly precise nanometer-scale materials (Rothemund, Nature 440:297-302, 2006; Douglas et al., Nature 459:414-418, 2009). These offer compelling advantages for biomedical applications.

Addressing the instability of DNA nanostructures in tissue culture.

DNA nanotechnology is an advanced technique that could contribute diagnostic, therapeutic, and biomedical research devices to nanomedicine. Although such devices are often developed and demonstrated using in vitro tissue culture models, these conditions may not be compatible with DNA nanostructure integrity and function. The purpose of this study was to characterize the sensitivity of 3D DNA nanostructures produced via the origami method to the in vitro tissue culture environment and identify solutions to prevent loss of nanostructure integrity.

Virus-inspired membrane encapsulation of DNA nanostructures to achieve in vivo stability.

DNA nanotechnology enables engineering of molecular-scale devices with exquisite control over geometry and site-specific functionalization. This capability promises compelling advantages in advancing nanomedicine; nevertheless, instability in biological environments and innate immune activation remain as obstacles for in vivo application. Natural particle systems (i.

Purification of DNA-origami nanostructures by rate-zonal centrifugation.

Most previously reported methods for purifying DNA-origami nanostructures rely on agarose-gel electrophoresis (AGE) for separation. Although AGE is routinely used to yield 0.1-1 µg purified DNA nanostructures, obtaining >100 µg of purified DNA-origami structure through AGE is typically laborious because of the post-electrophoresis extraction, desalting and concentration steps.

In vivo assembly of nanoparticle components to improve targeted cancer imaging.

Many small molecular anticancer agents are often ineffective at detecting or treating cancer due to their poor pharmacokinetics. Using nanoparticles as carriers can improve this because their large size reduces clearance and improves retention within tumors, but it also slows their rate of transfer from circulation into the tumor interstitium. Here, we demonstrate an alternative strategy whereby a molecular contrast agent and engineered nanoparticle undergo in vivo molecular assembly within tumors, combining the rapid influx of the smaller and high retention of the larger component.

Synthesis and surface modification of highly monodispersed, spherical gold nanoparticles of 50-200 nm.

Elucidating the impact of nanoparticle size and shape on biological systems is of fundamental importance to nanotoxicology and biomedicine. Currently, the ability to determine this is limited by the lack of a model nanoparticle system having a narrow size and shape distribution over the relevant size range (2-200 nm). Hydroquinone can be used to produce 50-200 nm gold nanoparticles that are relatively monodispersed in size with nearly spherical shapes.

Mediating tumor targeting efficiency of nanoparticles through design.

Here we systematically examined the effect of nanoparticle size (10-100 nm) and surface chemistry (i.e., poly(ethylene glycol)) on passive targeting of tumors in vivo.

Characterization of canine embryonic stem cell lines derived from different niche microenvironments.

Embryo-derived stem cells hold enormous potential for producing cell-based transplantation therapies, allowing high-throughput drug screening and delineating early embryonic development. However, potential clinical applications must first be tested for safety and efficacy in preclinical animal models. Due to physiological and genetic parity to humans, the domestic dog is widely used as a clinically relevant animal model for cardiovascular, neurodegenerative, orthopedic, and oncologic diseases.

Human immunodeficiency virus co-infection increases placental parasite density and transplacental malaria transmission in Western Kenya.

Plasmodium falciparum malaria and human immunodeficiency virus (HIV)-1 adversely interact in the context of pregnancy, however little is known regarding the influence of co-infection on the risk of congenital malaria. We aimed to determine the prevalence of placental and congenital malaria and impact of HIV co-infection on trans-placental malaria transmission in 157 parturient women and their infants by microscopy and by quantitative real-time polymerase chain reaction (PCR) in western Kenya. The prevalence of placental and cord blood infections were 17.

S-adenosylhomocysteine treatment of adult female fibroblasts alters X-chromosome inactivation and improves in vitro embryo development after somatic cell nuclear transfer.

The poor outcome of somatic cell nuclear transfer (SCNT) is thought to be a consequence of incomplete reprogramming of the donor cell. The objective of this study was to investigate the effects of treatment with S-adenosylhomocysteine (SAH) a DNA demethylation agent, on DNA methylation levels and X-chromosome inactivation status of bovine female fibroblast donor cells and the subsequent impact on developmental potential after SCNT. Compared with non-treated controls, the cells treated with SAH revealed (i) significantly (P<0.

Low oxygen delays fibroblast senescence despite shorter telomeres.

It has been widely accepted that telomere shortening acts as a cell division counting mechanism that beyond a set critical length signals cells to enter replicative senescence. In this study, we demonstrate that by simply lowering the oxygen content of the cell culture environment 10-fold (20-2%) extends the replicative lifespan of fetal bovine fibroblasts at least five-times (30-150 days). Although, low oxygen fibroblasts display a slightly slower rate (P > 0.

Convergence of quantum dot barcodes with microfluidics and signal processing for multiplexed high-throughput infectious disease diagnostics.

Through the convergence of nano- and microtechnologies (quantum dots and microfluidics), we have created a diagnostic system capable of multiplexed, high-throughput analysis of infectious agents in human serum samples. We demonstrate, as a proof-of-concept, the ability to detect serum biomarkers of the most globally prevalent blood-borne infectious diseases (i.e.

Telomere length status of somatic cell sheep clones and their offspring.

This study was carried out to determine the telomere length status of sheep clones and their offspring, and to examine telomere dynamics and chromosomal abnormalities in culture propagated donor cells. Skin samples were collected from somatic cell nuclear transfer-derived sheep clones, and three of their progeny generated by natural mating. Samples were collected from control animals (n = 35), spanning in age from 1 month to 36 months of age.

Telomere length analysis in goat clones and their offspring.

Incomplete epigenetic reprogramming of the donor genome is believed to be the cause behind the high rate of developmental mortality and post-natal anomalies observed in animal clones. It appears that overt phenotypic abnormalities are not transmitted to their progeny suggesting that epigenetic errors are corrected in the germline of clones. Here, we show variation in telomere lengths among Nigerian dwarf goat clones derived from different somatic cell types and that the offspring of two male clones have significantly shorter telomere lengths than age-matched noncloned animals.

Global gene expression response to telomerase in bovine adrenocortical cells.

The infinite proliferative capability of most immortalized cells is dependent upon the presence of the enzyme telomerase and its ability to maintain telomere length and structure. However, telomerase may be involved in a greater system than telomere length regulation, as recent evidence has shown it capable of increasing wound healing in vivo, and improving cellular proliferation rate and survival from apoptosis in vitro. Here, we describe the global gene expression response to ectopic telomerase expression in an in vitro bovine adrenocortical cell model.