Abstract: The present invention disclose a computerized system for designing nucleic acid sequences for gene expression comprising; (a) a server [103] for hosting a database [106] (b) a network connection [102] and (c) a computer readable medium [101] comprising functional modules including (i) a design module for enabling designing of nucleic acid constructs; (ii) interactive user interface module for visualizing biological information relating to design operations; (iii) transaction module for purchasing a user-designed or pre-stocked nucleic acid constructs (iv) a detecting module for detecting designed nucleic acid sequences comprises harmful sequences; the system is operating in a method of: (a) visualizing biological information; (b) designing nucleic acid sequences; (c) detecting and notifying when harmful sequences are designed; (d) providing means for transactions regarding ordering and purchasing said synthesized nucleic acids.