Nano technology

NANO TECHNOLOGYNANO ARTHOPEDICS

INTRODUCTION:-

In orthopedic implants, biomaterials (usually titanium and/or titanium alloys) often become encapsulated with undesirable soft fibrous but not hard bony tissue.

Considering electrical and mechanical properties for neural and orthopedic applications, carbon Nano fibers (CNs)/nanotubes have not been widely considered for these applications previously.

CN-reinforced polycarbonate urethane ( PU ) composite in an attempt to determine the possibility of using CNs as orthopedic prosthetic devices.

prosthetic= substitute

Reducing reaction to orthopedic implants

These materials enhanced osteoblast (bone-forming cell) functions whereas functions of cells that contribute to fibrous-tissue encapsulation events for bone implants (fibroblasts) decreased on PU composites containing increasing amounts of CNs.

super lattice coatings, which are nanostructures composed of alternating layers of dissimilar materials exhibit hardness and wear resistance far superior to their constituent materials.

Enhancing the Activity of Bone Cells on the Surface of Orthopedic Implants:-

It is very important to increase the activity of bone cells on the surface of materials used in the design of orthopedic implants so that such cells can promote either integration of these materials into surrounding bone or complete replacement with naturally produced bone if biodegradable materials are used.

It is generally accepted that a successful material should enhance osteoblast function, leading to more bone deposition and, consequently, increased strength of the interface between the material and juxtaposed bone.

A study has provided evidence of greater osteoblast function on carbon and alumina formulations that mimic the Nano dimensional crystal geometry of hydroxyapatite(HA) found in bone.

Juxtaposed=to place side by side, especially to contrast or comparison.

Nano bone implants:-

Resembles basic structure of bone. It uses the pH-induced self-assembly of a peptide amphiphile.

Design of peptide-amphiphile allows the Nano fibers to be reversibly cross linked to enhance or decrease their structural integrity.

. After crosslinking, the fibers are able to direct mineralization of HA to form a composite material in which the crystallographic c axes of HA are aligned with the long axes of the fibers.

Nano fibers, approximately 8nm in size, come in the form of a gel that could be injected into a broken bone to help the fracture-mending crystallization process.


Other than bone repairs, It could lead to development of a hardening gel that speeds the healing of fractures.

The three-dimensional porous scaffold materials mimic the microstructure of cancellous bone.

Cell culture and animal model tests showed that the composite material is bioactive. The Osteoblasts adhered, spread, and proliferated throughout the pores of the scaffold material within a week.

osteoblasts were separated from the neonatal rat calvaria. Osteoblasts adhered, spread, and proliferated throughout the pores of the scaffold material within the bone.

Cancellous=having low density and strength but high surface area of the kind that fills the inner cavity of long bones.

Scaffold=mould Proliferate=inc in no. Neonatal=new born Calvaria=dome or roof of da skull.


The technology has been found to be effective in repairing small bones ranging from 1 to 2cm in length, making the technology useful after removal of bone tumors.

Research is being performed on larger bone of 4 cm length.

Aligning nano tubesto improve artificial jonts :-

artificial joints might be improved by making the implants out of tiny carbon tubes ( diameter 60nm) and filaments that are all aligned in the same direction, mimicking the alignment of collagen fibers and natural ceramic crystals in real bones.

Nanotubes and nano fibers are aligned in the same direction and this orientation is similar to the way collagen and natural ceramic crystals, called hydroxyapatite, are aligned in bone.

One-third more bone forming cells (osteoblasts) attach to CNTs that possess surface bumps about as wide as 100nm than to conventional titanium, which has surface features on the scale of microns.


. The nanometer-scale bumps mimic surface features of proteins and natural tissues, prompting cells to stick better and promoting the growth of new cells.

There are two methods to align the tiny nanotube structures:-i. . In one method,researches mixed the nanotubes in a polymer and passed an

electric current through the mixture(Because nanotubes have the same natural electrical charge, they react to electricity by orienting themselves in the same direction. Once the polymer solidifies, the nanotubes are fixed in the aligned position.)


2)) In the second method, the nanotubes are poured into grids of tiny channels(Because the channels are so narrow, the tubes can only fit lengthwise, causing them to become aligned.)::::Future research may focus on combining the two methods for aligning nanotubes.

Cartilage Disorders of Knee Joint:-

The meniscus(knee’s shock absorber.It is a cartilage spacer for preventing friction and absorbing approximately one-third of the impact load that the joint cartilage surface experiences).

Unlike other body tissues, the meniscus does not repair itself because only a very small part receives blood.

Although the results are generally good in terms of relief of pain and recovery of function of the joint, there are long-term effects if the cartilage is lost and degenerative changes in the joints may occur.

. Procedures such as debridement, lavage, micro fracturing,subchondral bone drilling, and abrasion arthroplasty may perhaps alleviate symptoms, but cannot restore the hyaline articular cartilage.

Role of Nanotechnology in Engineering of a Replacement for Cartilage:-

is the use of nanotechnology to produce viable structural and functional scaffolds capable of promoting the growth of mesenchymal stem cells (MSCs), and differentiate these cells into meniscal tissue using a specially designed bioreactor.

they will attempt to create an artificial environment mimicking as closely as possible the meniscus and capable of recruiting cells from within the meniscal cavity to differentiate these cells into the various types that make up a healthy meniscus.

A thorough understanding is needed of how MSCs interact with scaffolds and how to optimize conditions promoting the cell growth around these scaffolds, which should not only encourage cell growth, but also degrade at the correct rate so that all that remains is meniscal tissue.

Nanotechnology as an Aid to Arthroscopy:-

Arthroscopy of joints, particularly the knee joint, is an established procedure for diagnosis and treatment.

. The first step was the study of cartilage by AFM as a basis for the construction of a scanning force arthroscope.

Cartilage stiffness was measured ex vivo at the micrometer and nanometer scales to explore structure–mechanical property relationships at smaller scales than has been done previously

From results of AFM imaging of cartilage, the micrometer-scale spherical tips resolved no fine structure except some chondrocytes, whereas the nanometer-scale pyramidal tips resolved individual collagen fibers and their 67-nm axial repeat distance.

Scanning Force Arthroscope:-

A prototype of the device constructed at Muller Institute for Structural Biology (Basel, Switzerland) combines both diagnostics and therapeutics in a single tube in contrast to the conventional arthroscopes which have two tubes:-

I. visualizationII. Manipulation It is user friendly. It provides information not obtainable by conventional methods. It is expected to

have an affordable price tag.

Thank you.. SARITA RAI (BM 3RD YR)

Nano technology

Engineering

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