Introduction to Biomedical Engineering - Assignment Example

1. Saccharides (sugars) end in –one. A polar functional group called the polymers makes the saccharides soluble in water.
2. Cellulose is the most common plant fiber.
3. The most commonly used synthetic hydrogels are polymers of acrylic acid, acrylamide, and 2-hydroxyethyl, methacrylate. The most biocompatible synthetic hydrogel is poly (2- hydroxyethyl methacrylate). It is commonly used for contact or intraocular lenses.
4. A sketch of the L-DOPA O

HO                                                                OH

                                                   NH2

HO

5. Quinones are free-radical former (polymerization initiator) that L-DOPA secretes.
6. Fluid Flow in most non-biological applications falls non-biological applications fall into either the laminar flow region for gas-phase flows or the turbulent region for liquid phase flows. For biological flows, one is often in the molecular flow regime.
7. 9. Yes, if the Knudsen number is greater than one (>1), the molecular is more likely to bump into another molecular or wall.
8. Molecular flow is also important in cell separation, especially in blood cell separation, cell manipulation, and protein analysis.
9. 1 (a) Artificial Kidney: Polyhydroxyethylmethacrylate (PHEMA) which is a cross-linked hydrogel. It is not absorbed by the body, capable of withstanding heat sterilization without damage, has resistance to degradation and contains water content similar to living tissue.

(b) Blood Vessels: Nitinol, a shape memory alloys is used as an artificial blood vessel-like a coronary artery.  The memory alloy has the capability of being deformed and going back to its original shape when pressure is released. The materials should be non-corrosive, have resistance to blood platelet, be durable, and non-toxic.

(c) Contact Lenses: Polyhydroxyethylmethacrylate (PHEMA) is also used in the production of contact lenses. It is selected since it can be organized into any shape or form; it can withstand degradation and can’t be absorbed by the body.

(d)  Artificial Heart: Polyethylene terephthalate (Knitted Dacron) and Polytetrafluoroethylene (PTFE) as vascular graft are in common use for the creation of artificial heart components. Materials should exhibit resistance to platelet and blood clotting, it should have biomechanical strength and durability, non-toxicity, and biocompatibility.

(e) Hip & Knee replacement: Materials used for hip & knee replacement are metallic biomaterials divided into 3 groups namely; cobalt-base alloys, iron-base alloys which are the same as stainless steels, and titanium-base alloys.  Metals are picked since they are high in strength, they resist corrosion and fracture

(f) Dental Implants, adhesives/types of cement: Selected alloys of titanium or cobalt chrome are commonly used as dental implants since they are less corrosive and do not cause unnecessary stress to the adjacent organ because they are less stiff. 

(G). Drug Delivery Encapsulation: Calcium alginate hydrogel is used in encapsulating drugs vulnerable to ultrasound disruption.  The materials used are should be non-biodegradable but capable of surviving immune response.  Secondly, the biofunctional molecule used should be able to bond with the appropriate type of cell and finally, be able to respond to appropriate stimuli e.g. absorption of suitable biomarkers

11. 2 (a) Possible applications for silicone rubber include cooking, baking, and food storage products, medical devices and implants, and thirdly, attires like sportswear and undergarments. Silicone rubber is preferred due to its un-reactive nature, stability, and resistance to severe environments and still maintains its usefulness.

(b) Applications of Teflon (polytetrafluoroethylene) are non-stick coating on cooking pans, inner coating of containers and pipe-works for reactive and corrosive chemicals, and as a lubricant in moving mechanical parts.

This is b

1. Enderle John & Bronzino Joseph, Introduction to Biomedical Engineering, Third Edition, Academic Press Series

because of its non-reactive nature and its ability to reduce friction and energy consumption of machinery.

(c) Poly (2-hydroxyethyl methacrylate) is mostly used as it produces a minimal local reaction and it resists degradation in tissues. Its applications include contact or intraocular lenses.

5. 5. On polar surfaces, the bio-adhesive used for bonding is hydrogen bonding while on the non-polar surface,
6. 6. The tough protective covering or structural support of some organisms e.g. arthropods are known as chitin. Chitin is a polymer containing polysaccharides. Chitosan is a byproduct of chitin through deacetylation.

Insects like grasshoppers, crustaceans like crabs, and shelled mollusks are some of the biological organisms that have chitin either in egg sac or exoskeletons.