Nuestro Coloquio de Hoy

[Guillermo Hinojosa-Aguirre <hinojosa@xxxxxxxxxxxxxx>]

 Mensaje sin acentos.

 Estimados Colegas,

 Nuestro coloquio de hoy estara a cargo del Prof. Matthew R. Libera del
 Departamento de Ingenieria Quimica del Instituto Stevens de Tecnologia.
 Su platica se titula:

                      "Infection-Resisting Biomaterials"

 Esperamos contar con su amable presencia el dia de hoy miercoles 12 de
 mayo a las 5:30 PM en el auditorio del Instituto de Ciencias Fisicas de
 la UNAM- Campus Morelos.

 Atentamente:

 Maximino Aldana y Guillermo Hinojosa.

                                 ~ Abstract ~

 Infections are now recognized as a leading cause of failure in implanted
 biomedical devices. They occur when bacteria colonize a device surface,
 develop into a biofilm, and infect the surrounding tissue. Biofilms are
 extremely resistant to traditional antibiotic treatments, and
 implant-related failures can often only be resolved by removing the
 implant, clearing the infection, and later re-implanting a second device.
 The consequences to both patient wellbeing and the health-care system are
 enormous. The problem is particularly challenging for implants that
 require integration of the surrounding tissue. Many of the same
 properties that promote tissue-cell adhesion also
 promote bacterial adhesion. We have been learning to modify such surfaces
 with the goal of conferring upon them the new property of differential
 cell adhesion where desirable tissue-cell adhesion is preserved while
 bacterial adhesion is inhibited. One strategy is to laterally modulate
 surface cell adhesiveness at length scales comparable to the size of an
 individual bacterium. We prepare these surfaces using electron-beam
 patterning of poly(ethylene glycol) [PEG] thin films. We work with PEG
 because of its well-known antifouling properties. Energetic
 electrons can both crosslink PEG into microgel particles, with ~200 nm
 diameter, and graft them to the underlying substrate. These gel particles
 can be e-beam patterned at controllable inter-gel spacings with
 cell-adhesive surface in between them. We have found that the adhesion of
 staphylococcal bacteria to these surfaces decreases significantly as the
 inter-gel spacing approaches one micron, the characteristic size of these
 bacteria. Relevant tissue cells such as osteoblasts and fibroblasts, on
 the other hand, are nevertheless able to interact favorably
 with the micron-scale cell-adhesive regions that comprise the remainder
 of the surface. To translate this concept of length-scale-mediated
 differential cell adhesion into commercializable technology, we are also
 exploring the use of emulsion-polymerized PEG microgel particles. These
 can be deposited onto topographically complex surfaces by electrostatic
 self assembly, and we are finding similar differential cell-interactive
 behavior with these self-assembled surfaces.-