Forever young: how to control the elongation, differentiation, and proliferation of cells using nanotechnology.

Within the emerging field of stem cells there is a need for an environment that can regulate cell activity, to slow down differentiation or proliferation, in vitro or in vivo while remaining invisible to the immune system. By creating a nanoenvironment surrounding PC12 cells, Schwann cells, and neural precursor cells (NPCs), we were able to control the proliferation, elongation, differentiation, and maturation in vitro. We extended the method, using self-assembling nanofiber scaffold (SAPNS), to living animals with implants in the brain and spinal cord. Here we show that when cells are placed in a defined system we can delay their proliferation, differentiation, and maturation depending on the density of the cell population, density of the matrix, and the local environment. A combination of SAPNS and young cells can be implanted into the central nervous system (CNS), eliminating the need for immunosuppressants.

Using nanotechnology to design potential therapies for CNS regeneration.

The nanodelivery of therapeutics into the brain will require a step-change in thinking; overcoming the blood brain barrier is one of the major challenges to any neural therapy. The promise of nanotechnology is that the selective delivery of therapeutics can be delivered through to the brain without causing secondary damage. There are several formidable barriers that must be overcome in order to achieve axonal regeneration after injury in the CNS. The development of new biological materials, in particular biologically compatible scaffolds that can serve as permissive substrates for cell growth, differentiation and biological function is a key area for advancing medical technology. This review focuses on four areas: First, the barriers of delivering therapies to the central nervous system and how nanotechnology can potentially solve them; second, current research in neuro nanomedicine featuring brain repair, brain imaging, nanomachines, protein misfolding diseases, nanosurgery, implanted devices and nanotechnologies for crossing the blood brain barrier; third, health and safety issues and fourth, the future of neuro nanomedicine as it relates to the pharmaceutical industry.

Behavioral testing and preliminary analysis of the hamster visual system.

The dependence of visual orienting ability in hamsters on the axonal projections from retina to midbrain tectum provides experimenters with a good model for assessing the functional regeneration of this central nervous system axonal pathway. For reliable testing of this behavior, male animals at least 10-12 weeks old are prepared by regular pretesting, with all procedures carried out during the less active portion of the daily activity cycle. Using a sunflower seed attached to a small black ball held at the end of a stiff wire, and avoiding whisker contact, turning movements toward visual stimuli are video recorded from above. Because at the eye level, the nasal-most 30 degrees of the visual field can be seen by both the eyes, this part of the field is avoided in assessments of a single side. Daily sessions consist of ten presentations per side. Measures are frequency of responding and detailed turning trajectories. Complete assessment of the functional return of behavior in this testing paradigm takes 3-6 months to complete.