Not enough input arguments in line 9

I am trying to solve this ODE, but don't seem to have enough input arguments, am I incorrectly indexing time? Here's the code:

t= [0:90]; %length of dialysis, 90 min, 1 min increments
A = 21000; %Surface area of membrane cm^2
K = 0.01; %mass transfer coefficient of membrane
CBio = 0.1; % inital blood creatinine concentration mg/mL
VBdot = 200; %mg/min volumetric flow rate of blood
VDdot= 300; %mg/min volumetric flow rate of dialysate
VB = 5000; % mL volume of blood
CDi = 0; % concentration of creatinine in incoming dialysate solution
CBi(t) = CBio*exp^((VBdot/VB)*(exp^((-K*A)/VBdot)-1)*t); %amount of creatitine in blood vs. time available to remove
CBo(t) = CBi(t)-CDo; % amount of creatinine in blood leaving dialysis machine
CDo= 0;
[t,CDo] = ode45(@(t,CDo) K*A*((CBi(t)-(CBi(t)-2*CDo))/ln(CBi(t)/(CBi(t)-2*CDo)))/VDdot,t,CDo);
plot(t,CDo,'0')