Fig. 3

Representative force–distance curves measured in different experimental groups a1 Aβ42 monolayer incubated in blank solution for 24 h; a2 Aβ42 monolayer incubated in blank solution for 48 h; b1 Aβ42 monolayer incubated in the presence of Zn²⁺ for 24 h; b2 Aβ42 monolayer incubated in the presence of Zn²⁺ for 48 h; c1 Aβ42 monolayer incubated in the presence of Ca²⁺ for 24 h; c2 Aβ42 monolayer incubated in the presence of Ca²⁺ for 48 h; d1 Aβ42 monolayer incubated in the presence of Al³⁺ for 24 h; d2 Aβ42 monolayer incubated in the presence of Al³⁺ for 48 h. (red line––approach trace, blue line––retract trace)