Science Essays

Abstract

Today, breast cancer is the most widespread cancer among women and each year, many women will die from this disease. For this reason, the diagnosis of breast cancer in the avoidance of women death is very effective. Many new techniques have been urban to detect breast cancer. One of them is the use of Nano particles. Various types of Nano particles both alone or in combination with other methods, such as CT scan and MRI used to diagnosis of breast cancer. In this paper we compared the advantages and disadvantages of two gold Nano particles and quantum dots. In this study, gold Nano particles with different shapes and sizes and quantum dots with the 566 and 556 wavelength used .They are binding to HER2 and Ki67 antibodies help to detect breast cancer. The diagnosis of cancer is probable by these nano particles which emission fluorescence lights. Also these two types of Nano particles in terms of optical properties, toxicity, cellular uptake and binding to the antibodies are compared together. Despite all the advances in medical nanotechnology there is still a long way from lab to clinical practice.

Introduction

There are various different type of cell in the body, and a lot of different type of malignancy which arise from different type of cell. (1) One of this is the breast cancer each year more than one million person are diagnose by breast cancer worldwide .more than semi of them will die from this sickness(2 ). Breast cancer is characterized by the uncontrolled expansion of abnormal cells in the milk producing glands of the breast or in the ducts that send milk to the nipple. The majority of breast tumors are carcinomas.(3) There are many way to identify breast cancer counting mammography can be noted that the traditional way.(4) New ways to detect breast cancer have been urbanized which are include using of the Nano particles. There are many profit of using Nano particles These include lower cost, higher precision, resolution at the cellular level, and early detection.(5-6) In this review article, we compare advantages and disadvantages of gold Nano particles and quantum dots, which are used for the detection of breast cancer by binding them to Her_2 and Ki67 anti bodies .

In the past few decades, technology has set immeasurable strides to let visualization, identification, and quantization in biological systems. Several of this technological advancement is occurring on the nanometer range, where multiple scientific disciplines are combining to make novel material by improved property. The integration of inorganic synthetic approaches with a size decrease to the Nano-scale has lead to the formation of a novel category of visual reporters, called qds. (7)

These semiconductor qd Nano crystals have emerged as a different from organic dyes and fluorescent proteins. The broad absorption spectrum, thin emission, photo-stability, not have of photo-bleaching, and high-quantum efficiency have ready these nanostructures very attractive imaging/sensing materials in contrast with the dye flour probes. (7-8-9)

Quantum dots have tunable optical property that have proved practical in a wide range of applications from multiplexed analysis such as DNA detection and cell organization and tracking, to most recently demonstrating promise for in vivo imaging and diagnostics. (10)usually, the fluorescence of QDs depends on the size or shape of the intrinsic Nano particle. QDs can be finely modified via their size and composition to get suitable excitation profiles and high absorption coefficients. (10-9) also, QDs show large Stokes shifts and can endure photo bleaching. For the biological applications of QDs, it is important to manage the surface of core with other semiconductor materials with higher band gap than the core as well as biocompatible polymer. In most of studies, zinc sulfide (ZnS) has been use to cover the core. (10-11)

QDs optical properties can be studied in the assembly or single molecular of physical materials have distinct absorption and emission spectrum for themselves that can be used to recognize for them. They make significant data as stoke shift, inhomogeneous broadening, and thermal spectrum view. (12)

The inhomogeneous broadening arise from variety in QDs size and there is strongly related to electronic organization; optical properties, and particle size. In the absorption spectrum, the decreasing of QD size shifts the onset of it to a visible area due to the growing of band gap energy, moreover by change of the QD size, its emission wavelength and color can be adjusted. (13)

The impact of advances in nanotechnology is particularly related in bio diagnostics, where Nano particle based assays have been urbanized for specific detection of bio analyses of clinical importance.(14, 15) Gold Nano particles show simply tuned physical properties, counting unique optical properties, robustness, and high surface areas, make them ideal candidates for developing biomarker platforms. (16)Modulation of these physicochemical properties can be easily achieved by satisfactory synthetic strategy and give gold Nano particles advantages over conventional detection methods currently used in clinical diagnostics (17)

The surface of gold Nano particles can be modified by ligand fictionalization to selectively attach biomarkers. Thiol-linking of DNA and chemical fictionalization of gold Nano particles for specific protein/antibody binding are the most ordinary approach. Simple and cheap methods based on these bio-Nano probes. (17,18)

AuNP-based diagnostics can be generally divided in three different Approaches:

1. Utilization of the AuNP color variety upon aggregation, the best characterized example being AuNPs functionalized by ssDNA capable of specifically hybridizing to a complementary goal for the detection of specific nucleic acid sequence in biological samples (19);

2. Use of AuNPs as a core/seed that can be modified with a wide variety of surface functionalities to give highly selective Nano probes for diagnosis (20);

3. Utilization of AuNPs in electrochemical based methods.

That can be joined with metal deposition for signal enhancement. (21)Gold Nano particles have been broadly studied for their unique optical properties arising from their surface Plasmon resonance (SPR) (18, 22, 23). Au NPs have extremely high absorption coefficients, allowing higher sensitivity in visual detection methods than usual dyes. (22-24) typically, colloidal solutions of sphere-shaped Au NPs are red with the SPR band centered at ca. 520 nm. This band is feebly dependant on the size of the particle and the refractive index of the immediate media but strongly changes by shape, and inter-particle distance The Morphology and surface chemistry of Nano particles is typically controlled by using suitable synthetic methods (25)

The great enhancement of electromagnetic field at the surface of AuNPs by interaction with electromagnetic waves offers other attractive optical properties with great potential for bio diagnostic assay. For example, AuNPs have been used for single-molecule detection by surface-enhanced Raman spectroscopy (SERS) (26) the successful operation of AuNPs in biological assays relies on the availability of synthetic methods generating Nano particles with the desired characteristics, namely high solubility in water, and adequate morphology, size dispersion, and surface functionalities (27).

Her-2 and Ki 67 antibodies:

Your pathology report might contain information concerning the rate of cell growth — what proportion of the cancer cells within the tumor are growing and dividing to make new tumor cells. A higher percentage suggests a faster-growing, extra aggressive cancer, rather than a slower, “laid back”

one of this examination is measurement of the Ki67.(28) Antigen Ki-67 in addition known as Ki-67 or MKI67 is a protein that in humans is encoded by the MKI67 gene antigen identified by monoclonal antibody Ki-67As a marker for tumor cell proliferation, Ki67 has significant impacts on breast cancer (BC) prognosis Ki-67 is a cancer antigen that is found in growing, dividing cells but is not present in the resting phase of cell growth. This characteristic makes Ki-67 a good cancer marker. This experiment is done on a section of tumor tissue, to help predict your prognosis. (28, 29)

Ki67 is a nuclear antigen firstly identified by Gerdes et al in the early 1980s, by using a mouse monoclonal antibody against a nuclear antigen from a Hodgkin lymphoma-derived cell line. The antigen named following the researcher’s location, Ki67 for Kiel University, Germany, with the 67 label referring to the clone number on the 96-well plate. (30) As a wildly used proliferation marker, Ki67 has attracted increasing notice in current years. a lot of studies showed that Ki67 appearance levels were negatively correlated with BC prognosis (30,31). on the other hand, it is hard to manually measure the Ki67 expression precisely and objectively, significantly limiting its clinical application. The majority common analysis method of Ki-67 antigen is the immune histo chemical evaluation. It was shown that Ki-67 nuclear antigen is expressed in certain phases of the cell sequence namely S, G1, G2, and M phases, but is non existing in G0 (32). In samples from normal breast tissue, it was found that Ki-67 is also expressed at low level (3 % of cells) in ER-negative cells, but not in ER-positive cells In breast cancer, a result of fewer than 10% is considered low, 10-20% borderline, and high if more than 20%.(31-33)

Receptor tyrosine-protein kinas erbB-2, too known as CD340 (cluster of differentiation 340), proto-oncogene Neu, Erbb2 (rodent), or ERBB2 (human). It is a protein that in humans is encoded by the ERBB2 gene, and it is also often called HER2 (from human epidermal growth factor receptor 2) or HER2/neu. (34) HER2 is a member of the human epidermal growth factor receptor (HER/EGFR/ERBB) family. Amplification or over-expression of this oncogene has been shown to play an significant role in the development and progression of certain aggressive types of breast cancer. In recent time the protein has become an important biomarker and aim of therapy for about 30% of breast cancer patients. (34, 35)

Her-2 a known proto-oncogene, is placed at the long arm of human chromosome 17(36)

The ErbB family consists of four plasma membrane-bound receptor tyrosine kinesis. One of which is erbB-2, and the other members being epidermal growth factor receptor, erbB-3 (neuregulin-binding; lack kinas domain), and erbB-4. (37)All four have an extracellular ligand binding domain, a trans membrane domain, and an intracellular domain that be able to interact by a large amount of signaling molecules and show both ligand-dependent and ligand-independent activity. Particularly, no ligands for HER2 have yet been acknowledged. HER2 can heterodimerise by any of the other three receptors and is considered to be the ideal dimidiation equal of the other ErbB receptors. (38)

Amplification, too known as the over-expression of the her2 gene, occurs in about 15-30% of breast cancers. It is robustly related with increased disease recurrence and a poor prognosis. Over-expression is too known to occur in ovarian, stomach, causes adenoid carcinoma of the lung. Review this essay:

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