Nanorods to kill bugs, cancer
doi:10.1038/nindia.2011.88 Published online 23 June 2011
Researchers have designed a new type of nanorod by hydroxyapatite (HAp) crystals with lanthanum. The new nanorods are able to carry and deliver antibiotics and cancer drugs, which could be useful for treating bacterial infection and cancers.
HAp crystals are composed primarily of calcium phosphate, which forms part of natural bone. These crystals can also be synthesized in a laboratory to repair bone defects, tooth decay and maxillofacial reconstruction. However, pure HAp crystals have limited applications, owing to their low mechanical strength.
The researchers doped nanorod-shaped HAp crystals with lanthanum and tested their efficacy for delivering antibiotics and cancer drugs. The crystals were between 75 nm and 100 nm in size. The researchers studied the efficacy of the doped crystals for delivering the antibiotic amoxicillin, as well as their inhibitory effects on four strains of bacteria: Escherichia coli, Staphylococcus aureus, Bacillus subtilis and Pseudomonas aeruginosa.
The doped crystals proved more effective than pure crystals for inhibiting the growth of the four bacterial strains. Doping increased both the hardness and surface area of the crystals, which might have played a vital role in achieving the sustained release of amoxicillin. The presence of lanthanum was found to inhibit the dissolution rate of HAp crystals in simulated body fluids, which could be used to prevent tooth decay. Doping with lanthanum also extended the sustained release of antibiotics by up to 76 hours, which could be used to prevent various infections during surgery.
The researchers say that the lanthanum-doped HAp crystals also demonstrated the sustained release of the anticancer drug 5-fluorouracil, an important drug in cancer chemotherapy. They assert that this will be helpful in the treatment of drug-resistant cancers.