Properties and Functions of Bone

Natural bone is a composite material composed of organic compounds (mainly collagen) reinforced with inorganic compounds (minerals). Apparently, the single mineral phase of bone is too brittle and easy to break while the single collagen phase is too soft and does not have mechanical stability (such as compression strength). The composite chemistry of bone provides both strength and resilience so that the skeleton can absorb energy when stressed without breaking. The detailed composition of bone...

Surface Treatment on Mg Alloys for Controlling Biofunctionality and Biodegradation

The surface of Mg alloys can be treated with bioresorbable ceramics or polymers along with novel signaling biomolecules (such as growth factors, DNA, and proteins) or pharmaceutical agents (such as antibiotics, anti-inflammatory drugs) to control their biodegradation and biofunctionality. 3.4.1 Bioresorbable Ceramic Coatings on Mg Alloys Surface treatment can improve the biocompatibility of Mg alloys by reducing the degradation rate and inducing better tissue-implant integration. Calcium...

Disadvantages of QDs

The main disadvantages of QDs are due to their composition of heavy metals (e.g., Cd, Pb, and Se which are known to be toxic to vertebrate systems at parts-per-million concentrations (Hardman 2006)) and the instability of uncoated QDs when exposed to UV radiation which leads to the release of heavy metal ions. For example, the free cadmium in solution can bind to sulfhydryl groups of critical mitochondrial proteins. Thiol group inactivation then leads to oxidative stress and mitochondrial...

Quantum Dots in Cancer Imaging and Treatment 521 Active and Passive Targeting for QDs

Having superior light-emitting properties, QDs are excellent candidates for tumor imaging if they can be effectively delivered to tumor sites. Both passive and active targeting mechanisms are being aggressively pursued in order to achieve this goal. Numerous studies have reported methods to lengthen circulation time of QDs in the blood and target QDs to cancerous tissues Gao et al. 2004a kerman et al. 2002 Rosenthal et al. 2002 . Coating QDs with polymers such as PEG to avoid uptake by the RES,...

Liposomes and their Advantages in Drug Delivery

Liposomes are spherical, self-closed vesicles formed by one or several concentric lipid bilayers with an aqueous phase inside and between the lipid bilayers Fig. 3a . Therefore, liposomes usually have hydrophilic outer surfaces, hydrophilic inner cores, and hydrophobic matrices in between. Figure 3b gives an example of a transmission electron microscope TEM image of liposomes adapted with permission from reference Ran et al. 2002 . There are several advantages of using liposomes for drug...

Conductive and Piezoelectric Materials

Piezoelectric Aebischer et al. 1987 materials have also been shown to enhance neural cell function without any external electrical stimulation. Conductive polymers, typically PPy, have been shown to be a permissive substrate for axonal growth in vitro and in vivo. However, studies have shown that an electrical stimulus applied to the conducting polymer was needed to enhance axon outgrowth to levels beyond that which would be expected on an inert, biocompatible polymer Schmidt et al. 1997 Zhang...

Carbon Nanotube Based Orthopedic Implant Sensors

Abstract In this chapter, the use of multiwalled carbon nanotubes MWCNTs as sensors for healthy bone growth will be discussed. MWCNTs are cytocompat-ible with osteoblasts bone-forming cells and enhance osteoblast calcium deposition, and thus, bone formation. Moreover, here, MWCNTs have been grown out of nanopores of anodized titanium MWCNT-Ti , which has a surface layer of titanium oxide a popular chemistry for orthopedic implants , to serve as a novel in situ orthopedic implant sensor. The...

Repair Strategies in the PNS

While damaged tissue in the PNS is able to spontaneously regenerate after injury, the regeneration rate is quite slow. Axonal growth rates have been estimated at about 0.5-1 mm day Archibald et al. 1995 . Although those growth rates may translate into the bridging of a several millimeter nerve gap in a matter of days, reinnervation of target tissue can take months. Accelerating recovery is desirable due to the loss of function prior to appreciable tissue regeneration. The slow growth of axons...

Piezoelectric Nanomaterials

The next generation of biomaterials should include combinations of the above known stimulatory cues. Conductive or piezoelectric nanomaterials may elicit superior regenerative response compared to conductive, piezoelectric, or nanoscale materials alone. To date, few studies have combined nanomaterials with such known stimulatory electrical cues. An electrical stimulus may be incorporated into a nanomaterial scaffold by selecting a material that is piezoelectric. Ceramics, such as zinc oxide ZnO...

Electrically Active Neural Biomaterials

Webster Abstract Numerous biomaterials have provided promising results toward improving the function of nervous system tissue. However, significant hurdles, such as delayed or incomplete tissue regeneration, remain toward full functional recovery of peripheral and central nervous system CNS tissue. Because of this continual need for better nervous system biomaterials, more recent approaches to design the next generation of tissue engineering scaffolds for the...

Wireless Medical Monitor Advantages and Disadvantages The Concept

There are two essential categories of wireless medical devices 1 wireless medical monitors and 2 wireless medical devices. Differences between these categories involve whether the devices only monitor health or also treat a medical problem. Wireless physiological measurements have a number of advantages over wired measurements, including ease of use, reduced risk of infection, reduced risk of failure, reduced user discomfort, enhanced mobility, and lower cost of care delivery Fig. 1 An...

Monitoring Tissue Healing Through Nanosensors

Abstract Nanotechnology is the use of materials with at least one dimension less than 100 nm. Nanotechnology has already revolutionized numerous fields, from construction to computers. Recently, nanotechnology has also been used to improve disease detection and treatment by developing wireless in situ sensors. Importantly, the use of wireless technologies in medicine, such as wireless body area networks and wireless personal area networks, is not new as they provide many promising applications...

Disadvantages of SPMNPs

In spite of the very exciting properties SPMNPs can offer, there are still several problems associated with using these nanoparticles in cancer diagnostics and therapeutics, especially for magnetically targeted drug delivery Lubbe et al. 1999 . The first limitation lies in the use of magnets for attracting superparamagnetic particles. When dealing with the tumors which have a large distance to possibly position the magnets, magnetic field strength at the tumor site will not be enough to attract...