How can I fit this equation into my empirical cumulative density function (CDF) to find the unknowns?

The following equation is the theoretical equation for the cumulative density function (cdf) for my problem:

p0 is the matrix for initial value and p1 is the matrix for final values of unknowns.

Many thanks for your help in advance,

Farnood

KB= 1.38064852*(10^-23);  %Boltzmann constant
Temp = 273+22.3;            %Room Temperature in Kelvin
Beta = (KB*Temp)^(-1);
Vel = 81.38e-9;             % Tip Velocity (m/sec)
X_nano = (10^-9).*X;        % The Lateral Forces in Newton
Stat_DX_nano = (10^-9).*Stat_DELXX1_Trace;       %The DeltaX stats in meter (average and standard deviation)
mean_K_eff1_array = mean(K_eff1_array);          %Average of the stiffnesses

fun = @(p1,X_nano) 1-exp(-(p1(1,1)/(Vel*mean_K_eff1_array)).*X_nano(:,1)...
    .*exp(-Beta.*(p1(1,2)-Stat_DX_nano(1,1).*X_nano(:,1)))).*(1+...
    (Beta^2).*(p1(1,1)/(Vel*mean_K_eff1_array)).*X_nano(:,1)...
    .*exp(-Beta.*(p1(1,2)-Stat_DX_nano(1,1).*X_nano(:,1))).*...
    (p1(1,3)+(X_nano(:,1).*Stat_DX_nano(1,2)).^2)).^(-1/2);

p01(1) = 7.5;
p01(2) = 3.0200381506371e-9;
p01(3) = 1.0066793835457e-9;

[p1,res] = lsqcurvefit(fun,p01,X_nano,Y);%,lb,ub);%,options)

f_o1 = p1(1,1);
U_o1 = p1(1,2);
Var_U_o = p1(1,3);

yfit1 = fun(p1,X_nano);