AFM Studies Of Structure And Properties Of Stem Cells And Collagen

BALB/c murine embryonic stem(ES) cell membrane was observed by atomic force microscope(AFM) and scanning electron microscope(SEM) and the inner structure of ES cells was studied by transmission electron microscope(TEM)in order to gain the morphological characteristics of BALB/c murine embryonic stem(ES) cells.The three techniques were compared and the results showed that each technique had its advantages.Therefore,the newer technique(AFM) should be combined with the classical ones(SEM and TEM).The normal hematopoietic stem cells(HSC) or CD34+ cells were observed by AFM.The AFM images of single HSC and the ultrastructure of HSC membrane were gained.Meanwhile we observed the ultrastructure of red blood cell membrane .Five parameters(Rp-v, Median height, Mean height, Rrms and Ra) were measured to quantitatively compare the characteristics of hematopoietic stem cell membrane and red blood cell membrane.The difference of aggregation behavior of type I collagen from different species was investigated by means of AFM.The results indicated that the aggregation behavior of collagen molecules was different under the same experimental conditions due to the difference of species.Our conclusions can be as reference for the development and improvement of collagen products.The imaging conditions of near-field optical microscope(NSOM) were explored Through comparison experiments.the effects of probes and feedback system on the quality of NSOM images were investigated.With different scan size,the transmission-mode and reflection-mode NSOM optical images were achieved of self-assembled collagen.The NSOM technique was also compared with AFM.