DNA nanostructures are promising drug carriers with their intrinsic biocompatibility, uniformity and versatility. However, rapid serum disintegration leads to low bioavailability at targeted sites following systemic administration, hindering their biomedical applications. Here we demonstrate transdermal delivery of framework nucleic acids (FNAs) through topical applications. By designing FNAs with distinct shapes and sizes, we interrogate their penetration on mice and human skin explant. Skin histology reveals size-dependent penetration, with FNAs ≤75 nm effectively reaching dermis layer. 17 nm-tetrahedral FNAs show greatest penetration to 350 µm from skin periphery. Importantly, structural integrity is maintained during the skin penetration. Employing a mouse melanoma model, topical application of doxorubicin-loaded FNAs accommodates ≥2-fold improvement in drug accumulation and tumor inhibition relative to topically-applied free doxorubicin, or doxorubicin loaded in liposomes and polymeric nanoparticles. Programmable penetration with minimal systemic biodistribution underlines FNA potential as localized transdermal drug delivery carriers.

In this study, we used imaging and proteomics to identify the presence of virus-associated cellular proteins that may play a role in respiratory syncytial virus (RSV) maturation. Fluorescence microscopy of virus-infected cells revealed the presence of virus-induced cytoplasmic inclusion bodies and mature virus particles, the latter appearing as virus filaments. In situ electron tomography suggested that the virus filaments were complex structures that were able to package multiple copies of the virus genome. The virus particles were purified, and the protein content was analyzed by one-dimensional nano-LC MS/ MS. In addition to all the major virus structural proteins, 25 cellular proteins were also detected, including proteins associated with the cortical actin network, energy pathways, and heat shock proteins (HSP70, HSC70, and HSP90). Representative actin-associated proteins, HSC70, and HSP90 were selected for further biological validation. The presence of ␤-actin, filamin-1, cofilin-1, HSC70, and HSP90 in the virus preparation was confirmed by immunoblotting using relevant antibodies. Immunofluorescence microscopy of infected cells stained with antibodies against relevant virus and cellular proteins confirmed the presence of these cellular proteins in the virus filaments and inclusion bodies. The relevance of HSP90 to virus infection was examined using the specific inhibitors 17-N-Allylamino-17-demethoxygeldanamycin. Although virus protein expression was largely unaffected by these drugs, we noted that the formation of virus particles was inhibited, and virus transmission was impaired, suggesting an important role for HSP90 in virus maturation. This study highlights the utility of proteomics in facilitating both our understanding of the role that cellular proteins play during RSV maturation and, by extrapolation, the identification of new potential targets for antiviral therapy. Molecular & Cellular Proteomics 9:1829 -1848, 2010. Respiratory syncytial virus (RSV)1 belongs to the paramyxovirus group of viruses, and it is the most important respiratory virus causing lower respiratory tract infection in young children and neonates. The mature RSV particle comprises a ribonucleoparticle (RNP) core formed by the interaction between the viral genomic RNA (vRNA), the nucleocapsid (N) protein (42 kDa), the phospho (P) protein (35 kDa), and the large (L) protein (250 kDa). The RNP core is visualized by electron microscopy as a strand of repeating N protein subunits that form a herringbone-like structure of ϳ10 -20 nm in diameter (1). Although the minimal functional polymerase activity requires an association between the N, P, and L proteins and the virus genome vRNA (2-4), additional viral proteins called the M2-1 protein (22 kDa), M2-2 protein, and M protein (28 kDa) regulate the activity of the polymerase (5-8). The virus is surrounded by a lipid envelope that is formed from the host cell during the budding process in which the three virus membrane proteins are inserted. The G protein (90 kDa) mediates attachment of...

No abstract

Early detection of skin diseases is imperative for their effective treatment. However, fluorescence molecular probes that allow this are rare. The first activatable near-infrared (NIR) fluorescent molecular probe is reported for sensitive imaging of keloid cells, skin cells from abnormal scar fibrous lesions. As keloid cells have high expression levels of fibroblast activation protein-alpha (FAPα), the probe (FNP1) is designed to have a caged NIR dye and a FAPα-cleavable peptide substrate linked by a self-immolative segment. FNP1 can quickly and specifically turn on its fluorescence at 710 nm by 45-fold in the presence of FAPα, allowing it to effectively recognize keloid cells from normal skin cells. Integration of FNP1 with a simple microneedle-assisted topical application enables sensitive detection of keloid cells in metabolically-active human skin tissue with a theoretical limit of detection down to 20 000 cells.

In recent years, the potential of stem cell research for tissue engineering-based therapies and regenerative medicine clinical applications has become well established. In 2006, Chung pioneered the first entire organ transplant using adult stem cells and a scaffold for clinical evaluation. With this a new milestone was achieved, with seven patients with myelomeningocele receiving stem cell-derived bladder transplants resulting in substantial improvements in their quality of life. While a bladder is a relatively simple organ, the breakthrough highlights the incredible benefits that can be gained from the cross-disciplinary nature of tissue engineering and regenerative medicine (TERM) that encompasses stem cell research and stem cell bioprocessing. Unquestionably, the development of bioprocess technologies for the transfer of the current laboratory-based practice of stem cell tissue culture to the clinic as therapeutics necessitates the application of engineering principles and practices to achieve control, reproducibility, automation, validation and safety of the process and the product. The successful translation will require contributions from fundamental research (from developmental biology to the 'omics' technologies and advances in immunology) and from existing industrial practice (biologics), especially on automation, quality assurance and regulation. The timely development, integration and execution of various components will be critical-failures of the past (such as in the commercialization of skin equivalents) on marketing, pricing, production and advertising should not be repeated. This review aims to address the principles required for successful stem cell bioprocessing so that they can be applied deftly to clinical applications.