Edunomia – Un diari sobre aspectes de la Universitat – per Miquel Duran

Nanodiamants i medicina


Un article del Chemical & Engineering News titulat Nanodiamonds Fight Cancer comenta la utilitat de petits cristalls de carboni (nanodiamants) per ficar-se dins de les cèl.lules tumorals tot anar enganxats amb molècules d’un fàrmac antitumoral. Es tracta d’un exemple d’enginyeria biomèdica, en aquest cas del grup de recerca del prof. Dearn Ho, de la universitat americana Northwestern University (veure’n un comentari a Futura-Santé per a la teràpia gènica), ha estat publicat a Science Translational Medicine (Nanodiamond Therapeutic Delivery Agents Mediate Enhanced Chemoresistant Tumor Treatment ). Segons el C&EN,

By binding the cancer agent doxorubicin to nanodiamonds, Ho and his team demonstrated particle-mediated delivery of the drug to both liver and mammary gland tumor cells in mice. In both cases, seven days after injection, the drug-loaded nanodiamonds killed about three times as many tumor cells as doxorubicin alone. They also circulated in the blood of the mice 10 times as long as the unbound cancer agent.

When treated with a high dose (200 µg) of doxorubicin, mice riddled with mammary gland tumors died after 15 days. But those treated with an equivalent dose of a nanodiamond-doxorubicin complex , which is thought to release the drug slowly over time, had a nearly 100% survival rate over the course of the eight-week study, and their tumors decreased in size by about 50%.

“What is new and striking” about this work, says Fuyu Tamanoi, a biochemist at the University of California, Los Angeles, is that the nanodiamond-doxorubicin formulation blocks tumor growth in the mice with drug-resistant mammary gland tumors cells. “This suggests that nanodiamonds can overcome drug resistance,” he says.

Aquests nanodiamants són nanopartícules de diamant (és a dir, de carboni) de mida entre 2 i 8 nanometres (la distància d’enllaç carboni-carboni és aproximadament 0,15 nanometres), i sembla que tenen propietats electrostàtiques especials. Alguns dels carbonis són substituïts per altres elements (nitrogen), cosa que fa que hi hagi alguns defectes a l’estructura d’aquests materials (al menys en els nanodiamants generats per detonació d’un diamant mitjançant TNT).

Els nanodiamants tenen diferents aplicacions, entre elles l’esmentada en biomedicina, segons el web sobre diamants abazias :

Nanodiamonds have been used as light beacons for chemotherapy, medical treatment that sees chemicals killing harmful microorganisms, usually cancer cells. The nanodiamonds are used as light when they are attached to cancer cells as well as tumors. Now, medicine can be delivered to the right zone with increased accuracy. This shows you how small these nanometer-sized diamonds really are, that they actually attach to microscopic cells.

Additionally, scientists have found that carbon based nanodiamonds are soluble in water, and have goof biocompatibility. This means that these nanadiamonds, when used along with treatment, cause little to no inflammation in the body. This is a promising finding, though research is by no means complete. There are still scientists seeking to test the level of toxicity of these small diamonds, and how long they can remain in a person’s body before becoming toxic or from dissipating altogether. While it is known that nanodiamonds have a useful life, they are far from “forever” like full size diamonds. This is why using nanodiamonds in medical procedures is still experimental. Science is not quite at the point where full-scale clinical trials can commence. However, when more is learned regarding the affect of nanodiamonds in the body then more options may open up.

Segons la wikipedia , a més del seu interès en biomedicina, els nanodiamants tenen els usos

Lapping and polishing (e.g. Sufipol);
Additives to engine oils (e.g. ADDO);
Dry lubricants for metal industry (Drawing of W-, Mo-, V-, Rh-wires);
Reinforcing fillers for plastics and rubbers;
Additives to galvanic electrolytes (e.g. DiamoSilb).

A la mateixa wikipèdia s’hi fa referència a una altra versió del diamant: l‘hiperdiamant, generat per alta compressió de pols de ful.lerita (o sigui, de ful.lerens). Més encara, es pot trobar informació sobre diamantoids , que són molècules de carboni amb enllaços sp3 de diferent mida. El més senzill és l’adamantà. Tot plegat és un interessant camp interdisciplinar.



This entry was posted on 23/04/2011 by in Ciència and tagged .