Detecting protein aggregates on untreated human tissue samples by atomic force microscopy recognition imaging

We apply topography and recognition (TREC) imaging to the analysis of whole, untreated human tissue for what we believe to be the first time. Pseudoexfoliation syndrome (PEX), a well-known cause of irreversible blindness worldwide, is characterized by abnormal protein aggregation on the anterior lens capsule of the eye. However, the development of effective therapies has been hampered by a lack of detailed knowledge of the protein constituents in these pathological deposits and their distribution. Using both TREC and immunofluorescence, one of the proteins implicated in the PEX pathology--the apolipoprotein clusterin--was detected, and differences in its distribution pattern on the surface of untreated human lens capsule tissue in both PEX and normal control samples were investigated. Our study shows the potential of TREC imaging for the analysis of whole, untreated human tissue samples.