Atomic Force Microscopy on Biological Materials Related to Pathological Conditions

<div>(a) Force-distance curves. Interaction forces versus distance between the tip and the sample’s surface. (b) The Lennard–Jones potential. If <span class="nowrap"><svg height="14.6529pt" id="M7" style="vertical-align:-5.36457pt" version="1.1" viewbox="-0.0498162 -9.28833 38.5351 14.6529" width="38.5351pt" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink"><g transform="matrix(.013,0,0,-0.013,0,0)"><path d="M530 686C535 705 530 712 521 712C504 712 448 684 359 674L358 648H393C437 648 439 646 429 593L400 435C372 447 345 448 332 448C286 448 194 414 144 373C68 311 23 203 23 111C23 26 57 -12 91 -12C120 -12 147 3 188 29C227 54 290 102 341 170H343L322 71C308 6 320 -12 341 -12C373 -12 442 27 501 96L485 120C455 91 422 67 408 67C401 67 401 76 404 91C440 294 479 473 530 686ZM387 375L355 241C326 187 200 53 142 53C126 53 109 73 109 130C109 217 154 337 218 381C240 396 265 404 297 404S372 390 387 375Z"></path></g><g transform="matrix(.013,0,0,-0.013,10.847,0)"><path d="M512 230V281L75 514V456L453 256V254L75 55V-3L512 230Z"></path></g><g transform="matrix(.013,0,0,-0.013,22.11,0)"><path d="M530 686C535 705 530 712 521 712C504 712 448 684 359 674L358 648H393C437 648 439 646 429 593L400 435C372 447 345 448 332 448C286 448 194 414 144 373C68 311 23 203 23 111C23 26 57 -12 91 -12C120 -12 147 3 188 29C227 54 290 102 341 170H343L322 71C308 6 320 -12 341 -12C373 -12 442 27 501 96L485 120C455 91 422 67 408 67C401 67 401 76 404 91C440 294 479 473 530 686ZM387 375L355 241C326 187 200 53 142 53C126 53 109 73 109 130C109 217 154 337 218 381C240 396 265 404 297 404S372 390 387 375Z"></path></g><g transform="matrix(.0091,0,0,-0.0091,29.26,3.132)"><path d="M380 106C343 72 306 56 265 56C195 56 116 112 115 248C235 252 361 262 377 265C396 269 400 277 400 297C400 374 333 449 250 449H249C198 449 144 421 103 376S37 269 37 201C37 88 109 -12 232 -12C263 -12 332 6 395 84L380 106ZM225 412C281 412 315 364 314 312C314 297 308 292 290 292C232 290 176 289 120 289C135 370 180 412 225 412Z"></path></g><g transform="matrix(.0091,0,0,-0.0091,33.173,3.132)"><path d="M515 -240V-213C445 -206 438 -202 438 -132V332C438 399 440 418 441 439L437 442C421 434 408 431 402 431C394 430 389 431 375 435C363 440 342 445 306 449C168 450 38 341 38 197C38 101 108 -12 253 -12L359 30V-130C359 -201 353 -207 274 -213V-240H515ZM359 60C340 51 316 44 285 44C211 44 128 109 128 230C128 348 194 408 262 408C294 408 336 392 359 366V60Z"></path></g></svg>,</span> the resultant force is attractive, and if <span class="nowrap"><svg height="14.6529pt" id="M8" style="vertical-align:-5.36457pt" version="1.1" viewbox="-0.0498162 -9.28833 38.5351 14.6529" width="38.5351pt" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink"><g transform="matrix(.013,0,0,-0.013,0,0)"><path d="M530 686C535 705 530 712 521 712C504 712 448 684 359 674L358 648H393C437 648 439 646 429 593L400 435C372 447 345 448 332 448C286 448 194 414 144 373C68 311 23 203 23 111C23 26 57 -12 91 -12C120 -12 147 3 188 29C227 54 290 102 341 170H343L322 71C308 6 320 -12 341 -12C373 -12 442 27 501 96L485 120C455 91 422 67 408 67C401 67 401 76 404 91C440 294 479 473 530 686ZM387 375L355 241C326 187 200 53 142 53C126 53 109 73 109 130C109 217 154 337 218 381C240 396 265 404 297 404S372 390 387 375Z"></path></g><g transform="matrix(.013,0,0,-0.013,10.847,0)"><path d="M512 -3V55L134 254V256L512 456V514L75 281V230L512 -3Z"></path></g><g transform="matrix(.013,0,0,-0.013,22.11,0)"><path d="M530 686C535 705 530 712 521 712C504 712 448 684 359 674L358 648H393C437 648 439 646 429 593L400 435C372 447 345 448 332 448C286 448 194 414 144 373C68 311 23 203 23 111C23 26 57 -12 91 -12C120 -12 147 3 188 29C227 54 290 102 341 170H343L322 71C308 6 320 -12 341 -12C373 -12 442 27 501 96L485 120C455 91 422 67 408 67C401 67 401 76 404 91C440 294 479 473 530 686ZM387 375L355 241C326 187 200 53 142 53C126 53 109 73 109 130C109 217 154 337 218 381C240 396 265 404 297 404S372 390 387 375Z"></path></g><g transform="matrix(.0091,0,0,-0.0091,29.26,3.132)"><path d="M380 106C343 72 306 56 265 56C195 56 116 112 115 248C235 252 361 262 377 265C396 269 400 277 400 297C400 374 333 449 250 449H249C198 449 144 421 103 376S37 269 37 201C37 88 109 -12 232 -12C263 -12 332 6 395 84L380 106ZM225 412C281 412 315 364 314 312C314 297 308 292 290 292C232 290 176 289 120 289C135 370 180 412 225 412Z"></path></g><g transform="matrix(.0091,0,0,-0.0091,33.173,3.132)"><path d="M515 -240V-213C445 -206 438 -202 438 -132V332C438 399 440 418 441 439L437 442C421 434 408 431 402 431C394 430 389 431 375 435C363 440 342 445 306 449C168 450 38 341 38 197C38 101 108 -12 253 -12L359 30V-130C359 -201 353 -207 274 -213V-240H515ZM359 60C340 51 316 44 285 44C211 44 128 109 128 230C128 348 194 408 262 408C294 408 336 392 359 366V60Z"></path></g></svg>,</span> the resultant force is repulsive. In the case that <i>d</i> = <i>d</i><sub>eq</sub>, the resultant force is zero. (c) Repulsive and attractive forces on the tip. Forces applied on the AFM tip in three different regions.</div>

Scanning

fig2

Figure 2

Figure 2: Atomic Force Microscopy on Biological Materials Related to Pathological Conditions 