Patterned neuronal networks using nanodiamonds and the effect of varying nanodiamond properties on neuronal adhesion and outgrowth.

OBJECTIVE: Detonation nanodiamond monolayer coatings are exceptionally biocompatible substrates for in vitro cell culture. However, the ability of nanodiamond coatings of different origin, size, surface chemistry and morphology to promote neuronal adhesion, and the ability to pattern neurons with nanodiamonds have yet to be investigated. APPROACH: Various nanodiamond coatings of different type are investigated for their ability to promote neuronal adhesion with respect to surface coating parameters and neurite extension. Nanodiamond tracks are patterned using photolithography and reactive ion etching. MAIN RESULTS: Universal promotion of neuronal adhesion is observed on all coatings tested and analysis shows surface roughness to not be a sufficient metric to describe biocompatibility, but instead nanoparticle size and curvature shows a significant correlation with neurite extension. Furthermore, neuronal patterning is achieved with high contrast using patterned nanodiamond coatings down to at least 10 µm. SIGNIFICANCE: The results of nanoparticle size and curvature being influential upon neuronal adhesion has great implications towards biomaterial design, and the ability to pattern neurons using nanodiamond tracks shows great promise for applications both in vitro and in vivo.

A collaborative evaluation of a needle exchange program for youth.

Limited research has been conducted to examine the effectiveness of existing HIV prevention and harm reduction interventions targeted to injection drug-using youth. Moreover, although there are a growing number of needle exchange programs being developed for youth throughout the United States, the effects of these services have yet to be systematically evaluated. This article describes a collaborative evaluation conducted by the Division of Adolescent Medicine, Childrens Hospital Los Angeles, and Clean Needles Now, a needle exchange serving young injection drug users. The evaluation employed a multimethod research design that included both qualitative and quantitative methods. Findings are presented about how a community-based agency's service delivery philosophy can affect the design and implementation of an evaluation. Lessons learned from this collaborative evaluation are presented, including the potential benefits of incorporating harm reduction principles into research activities.

Drug use, needle sharing, and HIV risk among injection drug-using street youth.

Infection drug use is the second most common HIV risk behavior in the United States, but little is known about injection drug use and needle-sharing behavior among street youth, a group at high risk for HIV infection. This study investigates the drug use histories, injection drug use behaviors, and needle-sharing practices of 106 injection drug using youth in Los Angeles, California. Respondents report high rates of injection drug use and needle sharing, indicating that these youth are at particularly high risk for HIV infection. Results suggest a need for outreach services tailored to the unique needs of injection drug-using adolescents.