  In this paper, we propose a new Multiple-Input Multiple-Output (MIMO)
Molecular Communication (MC) system where multiple types of molecules are
utilized for transmission and reception of information. We call the proposed
framework as Multiple-type Transmission and Multiple-type Reception (MTMR). We
also obtain the bit error rate (BER) of the system and an optimization problem
is formulated to minimize BER by optimizing the drug dosage for designing drug
release mechanism. As numerical analysis shows, the BER of MIMO-MTMR in MC is
minimized to $\text{3.7}\times\text{10}^{\text{-3}}$ by considering the budget
of molecules as 10000. Furthermore, MIMO-MTMR outperforms Single-type
Transmission Single-type Reception MIMO from the BER performance point of view
approximately 54% for time slot 10s.
