exam 3- NP's in surgery Flashcards
(32 cards)
NP’s can enhance therapeutic effects of certain drugs by:
- increasing circulation time
- increasing stability/compatibility
- promoting cellular internalization
- targeted delivery
NP’s can enhance medical diagnosis by:
- improve detection limit of target molecules or cells
- reduce the amt of sample needed (or cost)
- faster
- less invasive methods
nanomedicine can improve surgery in 2 ways:
direct- when surgeon is performing surgery
indirect- not during surgery process, but prevents post-surgical complications
3 direct methods of how nanomedicine helps improve surgery
1- nano-endoscopy
2- nanocoated surgical blades
3- better bandage promotes powerful healing (hemostatic NPs)
performance of surgical blades can be enhanced significantly when hard metal is coated with ___ (___ or ___ structures)
diamonds
micro or nano
nanocoating of surgical tools with diamond NPs would allow cutting edge diameter in the region of ____
5 nm - 1 um
what can be the problem with regular surgical blades and how do diamonds help fix this?
surgical tools are metal, have to use pressure to cut through tissues, this can cause post-surgical inflammation
- diamond has a low friction coefficient, decreasing the penetration force (pressure) necessary
describe nanodiamonds- its properties and what its made of
- diamond is a solid form of the element carbon with its atoms arranged in a crystal structure called diamond cubic
- diamond has the highest hardness and thermal conductivity of any natural material (cutting and polishing tools)
- diamonds are made of carbon so they form as carbon atoms under high temp and pressure - they bond together to start growing crystals
nanodiamonds have excellent ___ and ___ properties, high ___ and turnable ___
they are also ___, which makes them well suited to biomedical applications
mechanical & optical
high surface areas
surface structures
non-toxic
why not have surgical blades completely made of diamonds?
surgeons still need some friction to know and feel what they are cutting through
describe the synthesis of nanodiamonds in labs
explosives with a negative oxygen balance (60% TNT & 40% hexogen) are detonated in a closed metallic chamber in an atmosphere of N2, CO2, and liquid or solid H2O
–> so you trigger the explosion –> waves of heat and energy where chemical rxn’s happen –> formation of carbon nanoclusters –> crystallization & growth of nanodiamonds
what is the purpose of hemostatic NPs
improve survival following blunt trauma (help prevent excessive bleeding, both internal & external bleeds)
- a solider can bleed out in 5-10 mins
hemostatic NPs (____) that can be administered intravenously to reduce bleeding times by ___% in a model of rat femoral artery injury
RGD-NPs
50%
structure of hemostatic NP
RGD-NPs : 400 nm core made of biodegradable block copolymer of PLGA with lysine component (PLL) with PEG arms terminated with arginine-glycine aspardic acid (GRG)- based targeting ligands
how do hemostatic NPs (RGD-NPs) help prevent bleeding
they enhance the aggregation of platelets (can resist very high temps)
clotting is the process by…
describe the components involved
the process by which blood changes from a liquid to a gel
platelets- a special type of blood cell that clumps after blood vessel injury
fibrinogen- fibrous protein
glycoprotein IIIb/IIa - the surface receptors on platelets
clotting process: the surface receptor (IIIb/IIa) grabs fibrinogen, another platelet grabs the same one —> they clot
what do the hemostatic NPs (RGD-NPs) target to enhance platelet clotting
they target the glycoprotein IIIb/IIa receptors on activated platelets (the NP works as an alternative to fibrinogen)
experiment done with mice to test the RGD-NPs
mice exposed to trauma to cause internal bleeding (liver clot triggered) & analyze survival 1 hour post-injury –>
saline control: mice only given saline –> 45% survived
mice given RGD-NPs –> 85% survive
peritoneal adhesions are mostly induced by…
surgical procedures in peritoneal cavity or pelvic area (abdominal area)
what are adhesions?
basically a film of connective tissue (fibrous bridge) containing blood vessels and nerve tissue that connect 2 organs (in a bad way)
what is the prevalence of peritoneal adhesions after major surgery procedures?
63 to 97%
when can symptoms of peritoneal adhesions begin to appear?
after years b/c adhesions can take years to grow
- bowel obstruction
- abdominal pain
- infertility
what is the current solution for peritoneal adhesions
incorporations of hydrogels into the area during surgery (hydrogel = water-swollen, and cross-linked polymeric network- polymer made of sugars
–> but these polymers can also trigger adhesions
how do hydrogels work
physical barriers- separate the injured regions during peritoneal healing- often made of polysaccharides or hydrogels
- both systems are rapidly cleared (cationic surface)
