Quantum dots (QDs) have a great potential to be applied as a biosensor to detect cancer cells because of their properties such as high photoluminescence, photo stability, narrow peak of luminescence, etc. However, cadmium sulphide (CdS) quantum dots are toxic and hydrophobic, making it impossible to be applied into biomaterials. A template is needed to make CdS QDs nontoxic and hydrophilic. The optical properties of these QDs are needed to be protected. To achieve this purpose, the template for CdS QDs has been designed by capping CdS QDs with apo-ferritin shells before aligning them onto cylindrical perpendicular PS-b-P2VP template, with the aim of locating CdS QDs appropriately in sequence. A host-guest system can be developed.