Microstructural characteristics of thin biofilms through optical and scanning electron microscopy

CORTIZO MC,; FERNÁNDEZ LORENZO DE MELE, M

WORLD JOURNAL OF MICROBIOLOGY & BIOTECHNOLOGY

SPRINGER

Año: 2003 vol. 19 p. 805 - 810

0959-3993

The combination of a conventional optical microscope with a specially designed glass flow cell was used to visualize?in situ? biofilms formed on opaque thin biomaterials through a simple non-invasive way (optical microscopy of thinbiofilms, OMTB). Comparisons of OMTB with scanning electron microscopy (SEM) images were made. Thinmetallic dental biomaterials were used as substrata. They were immersed in a synthetic saliva and in a modifiedMitis?Salivarius medium inoculated with a consortium of oral microorganisms. To study the effect of bacterialmotility, Pseudomonas fluorescens cultures were also used. The processes which give rise to the formation of thebiofilm were monitored through OMTB. Biofilm microstructures like pores, water channels, streamers and chains ofStreptococci, attached to the surface or floating in the viscous interfacial environment, could be distinguished.Thickness and roughness of the biofilms formed on thin substrata could also be evaluated. Distortions introducedby pretreatments carried out to prepare biological materials for SEM observations could be detected by comparingOMTB and SEM images. SEM images (obtained at high magnification but ex situ, not in real time and withpretreatment of the samples) and OMTB images (obtained in situ, without pretreatments, in real time but at lowmagnification) in combination provided complementary information to study biofilm processes on thin substrata.