Novel design of low voltage DC source for bio nano diagnostic applications

Recently, thin film sheets are produced by vapour deposition and self assembly techniques. But we introduced a novel method by using nano particles deposited using electrodepositing method mixed with the collagen thin film sheet. In this research paper we introduced a novel technique for thin film fabrication, impregnated with silver nano particles by electro deposition technique using constant voltage 12V DC or 9V DC. Due to low cost fabrication technique, many commercial integrated circuits (IC) such as regulated power supplies (RPS) are available for the past two decades. The power supply designed by us includes fairly simple, fixed voltage types of high quality precision regulators. These IC regulators have much improved performances as compared to those made from the discrete components. They have a number of unique built-in features such as current limiting, self protected against over temperature remote control operation over a wide range of input voltages and feedback current limiting. We used the IC regulators available in the market that produces fixed positive output voltages making them useful in a wide range of bio medical applications.


Introduction
Recently, thin film sheets are produced by vapour deposition and self assembly techniques. But we introduced a novel method by using nano particles deposited using electrodepositing method mixed with the collagen thin film sheet 1,2 . In this research paper we introduced a novel technique for thin film fabrication, impregnated with silver nano particles by electro deposition technique using constant voltage 12V DC or 9V DC. Due to low cost fabrication technique, many commercial integrated circuits (IC) such as regulated power supplies (RPS) are available for the past two decades. The power supply designed by us includes fairly simple, fixed voltage types of high quality precision regulators. These IC regulators have much improved performances as compared to those made from the discrete components. They have a number of unique built-in features such as current limiting, self protected against over temperature remote control operation over a wide range of input voltages and feedback current limiting. We used the IC regulators available in the market that produces fixed positive output voltages making them useful in a wide range of bio medical applications.

Procedure
By using the combination of electrochemical and electrophoretic technique, we prepared the hydroxyapatitechitosan film. "The migration of charged particles under the influence of electric field" was the basic principle for an electrodeposition of film. It consists of two electrodes such as anode and cathode. The cathode consists of Small Square of stainless steel plate for electrodeposition of film. The dissolved chitosan in hydrochloric acid contain the pH near three. After filtering undisclosed material, the pH of the chitosan solution was adjusted to seven using sodium hydroxide (1M). For electro deposition, cathode and anode electrodes were immersed in a suspension containing chitosan solution. Deposition was performed by connecting both the cathode and anode to a alternative current power supply and applying a voltage of 12V side by side added hydroxyapatite solution and maintain the pH of 7 using 0.1N sodium hydroxide. Chitosan contain free amino group which was migrated towards the cathode. When hydroxyapatite suspended in the chitosan became entrapped and deposited on the steel plate which was placed on the cathode. After deposition the electrodes were disconnected from the power supply, removed from the suspension, rinsed with distilled water and dried at room temperature. Then the film was examined by Fourier transform infrared spectroscopy (FT-IR). It has three terminals labelled as input, output and ground. The IC7812 is +12 Volt regulator and IC7809 is +9volt regulator. The filter consists of two capacitors namely C 1 and C 2 . The capacitor(C 1 ) with 0.33µF is required if power supply filter is located 3inches from the IC regulator and the capacitor(C 2 ) with 0.01 µF acts basically as line filter to improve transient response. Figure 2 shows the circuit indicating the use of 7805 as an adjustable voltage regulator the output voltage is given by the following equation V out = For the above equation 7805IC regulator, when the V fixed = 5Volt, Let R 1 and R 2 = 1kΩ and I q = 2mA, then its output voltage is V out = 15Volts. The input voltage for the IC regulator must be at least 2volt and above the output voltage. This is required in order to maintain regulation. The input voltage should not be more than 35 or 45Volts depending upon the requirement. The circuit inside all the IC regulators have internal thermal overload protection and short circuit current limiting features. Thermal overload in a IC regulator occurs whenever the internal power dissipation becomes excessive and the temperature of the device exceeds a certain value. IJBAR (2013) 04 (10) www.ssjournals.com

Power supply design and fabrication
The prototype power supply with anode and cathode terminals attached with DC power supply of 12 V, 1A with Stirrer. Stirrer is attached with 9V/750 mA power supply. The stirrer speed can be varied from low rpm to high rpm [up to 1200 rpm]. The anode and cathode terminals are immersed in electrolyte with silver nano particle. Due to electro deposition method the silver nano particles are deposited on the cathode terminal. The chitosan with silver nano particle in the form of paste is deposited on the cathode and the the paste is later made as a thin film using self assembly method.

Fig.3 FTR spectrum of chitosan-hydroxyapatite.
Fourier Transform Infrared Spectroscopy spectrum of chitosan-hydroxyapatite composite film shows the characteristic peaks of chotosan and hydroxyapatite. The free ammonia groups are shown at 1637 cm -1 .The-CH 2 -CH 2 -Vibration were observed at 2920 cm-1,the vibration modes of V 1 ,V 3 and V 4 of phosphate ion absorbed from the spectrum, well dissolved bands at 602,580 and 536 represent V 4 vibration modes.
Chitosan is a linear polysaccharide composed of randomly distributed β-(1-4)-linked D-glucosamine (deacetylated unit) and N-acetyl-D-glucosamine (acetylated unit). It is made by treating shrimp and other crustacean shells with the alkali sodium hydroxide.

Hydroxyapatite
The term "apatite"applies to a group of compounds (not only at calcium phosphates) with a general formula in the form M 10 (XO 4 ) 6 Z 2 , where M 2+ is a metal and species XO 43 -and Z-are anions. The particular name of each apatite depends on the elements or radicals M, X and Z. In these terms, hydroxyapatite (HAp) has the molecular structure of apatite, where M is calcium (Ca 2+ ), X is phosphorus (P 5+ ) and Z is the hydroxyl radical (OH-). This is known as stoichiometric hydroxyapatite and its atomic ratio Ca/P is 1.67. Its chemical formula is Ca 10 (PO 4 ) 6 (OH) 2 , with 39% by weight of Ca, IJBAR (2013) 04 (10) www.ssjournals.com 18.5% P and 3.38% of OH. Hydroxyapatite crystallizes in a hexagonal system, although with some exception in a monoclinic system. The system belongs to the hexagonal space group P63/m, with hexagonal rotational symmetry and a reflection plane and with cell parameters of a=b=9.418 Å y c=6.884 Å. Figure 1 shows the unit cell of hydroxyapatite. HAp structure is formed by a tetrahedral arrangement of phosphate (PO 43-), which constitute the "skeleton" of the unit cell. Two of the oxygens are aligned with the c axis and the other two are in a horizontal plane. Within the unit cell, phosphates are divided into two layers, with heights of 1/4 and 3/4, respectively, resulting in the formation of two types of channels along the c axis, denoted by A and B(figure.4).

Figure.5. Chitosan powder from sea foods
The first patent on producing chitosan was taken out in the 1920`s, since then there havecdf been taken out several hundred patents on production and even more on application. Although there have been used extensive resources on both research and development of processes and application, it's only the last two decades chitosan has been an industrial available product in large scale quantities.

A polysaccharide
Chitosan is made by alkaline N-deacetylation of chitin, (Fig. 5). The term chitosan does not refer to a uniquely defined compound, it merely refers to a family of copolymers with various fractions of acetylated units. It consists of two types of monomers; chitin-monomers and chitosan-monomers. Chitin is a linear polysaccharide consisting of (1-4)-linked 2acetamido-2-deoxy-b -D-glucopyranose. Chitosan is a linear polysaccharide consisting of (1-4)-linked 2-amino-2-deoxy-b-D-glucopyranose.Commercial, chitin and chitosan consists of both types of monomers. Chitosan is found in nature, to a lesser extent than chitin, in the cell walls of fungi. Chitin is believed to be the second most abundant biomaterial after cellulose. The annual biosynthesis of chitin has been estimated to 10 9 to 10 11 tons. Chitin is widely distributed in the nature. Among several sources the exoskeleton of crustaceans consist of 15-20 % chitin of dry weight. Chitin found in nature is a renewable Bio-resource. Chitin is similar to cellulose both in chemical structure and in biological function as a structural polymer. The crystalline structure of chitin has been shown to be similar to cellulose in the arrangements of inter-and intrachain hydrogen bonding. It has been proposed to define chitosan and chitin as soluble or insoluble in 0.1 M acetic acid, respectively or by degree of deacetylation, >20 % of deacetylation is proposed defined as chitosan.

Cationic Nature
The main interest in chitosan derives from its cationic nature in acidic solutions, which provides unique properties relative to other polysaccharides which are usually neutral or negatively charged. The cationic nature allows chitosan to be used in among other applications waste-water treatment. Positively charged chitosans reacts with organic solids and cell surfaces which are usually negatively charged. Another useful property is that it is possible to control the solubility and the charge density by varying the mole fraction of N-acetylated units. Regarding potential applications of chitosan in watersolutions, control of the solubility of the chitosans is of primary importance.In general, the solubility of heteroglucans are influenced by the polarity and size of the monomers, distribution of the monomers along the chain, the flexibility of the chain, branching, charge density and molecular weight of the polymer.

Product characterization
Both chitin and chitosan are naturally biodegrable and nontoxic products. Chitosan can be described in general by the following parameters:Degree of deacetylation in %, Dry matter in %,Ash in %,Protein in %, Viscosity in Centipoise, Intrinsic viscosity in ml/g, Molecular weight in g/mol: average MW of 4.5 x 10(4) g/mol and a numerical MW of 1.7 x 10(4) g/mol, Turbidity in NTU units. All these parameters can be adjusted to the application chitosan is being used for. The main parameters that influence on the product properties is as mentioned above, the degree of deacetylation and viscosity. The deacetylation is very important to get a soluble product. But it`s not only the degree of deacetylation that influence on the solubility. The distributions of the acetyl groups are also important. Viscosity can be adjusted to each application, by controlling our process parameters. The range of viscosity is from 10 to 5000 cp( Figure.6 &7).

Applications
Chitosan is unique, with a polyamin character which makes it soluble (at acid pH), positively charged, different viscosity and easily modified chemically. These properties confer upon chitosan potential applications in: Bio-medicine, Biotechnology, Agriculture, Cosmetics, Shampoo, Toothpaste, Contact lenses, Clarification, Recovery of proteins, Emulsions, Coatings, Pollution treatment, Adhesives, Industry.  (10) www.ssjournals.com Chitosan has a number of commercial and possible biomedical uses. It can be used in agriculture as a seed treatment and bio pesticide, helping plants to fight off fungal infections. In winemaking it can be used as a fining agent, also helping to prevent spoilage. In industry, it can be used in a self-healing polyurethane paint coating. In medicine, it may be useful in bandages to reduce bleeding and as an antibacterial agent; it can also be used to help deliver drugs through the skin.
The FTIR spectra of HA and 20CS-80HA powders are given in Fig. 8. In the FTIR of 500±C-sintered pure HA ( Fig. 8(a)), the absorption bands around 1037, 963 and 603, 565 cm -1 are ascribed to the stretching vibration and bending vibration of PO 4 respectively 10 . The double peaks at 1416, 1464 cm -1 and absorption peak of 873 cm -1 were the typical absorption peaks of CO 23 , indicating that HA contained CO 3/2 . 11 The absorption peaks of 3426 and 1635 cm -1 were caused by absorbed water and stretching vibration of the O-H group. The FTIR analysis of 500±C-sintered 20CS-80HA showed that the strong peaks at 564, 604, 1044 and 3415 cm -1 caused by PO 3/4 and OH vibration still existed, but the peaks of CO 2/3 disappeared (Fig. 3(b)). From the FTIR spectra of 20CS-80HA dried at 130±C, it can be seen that the typical peaks of PO 4/3 (1034, 603 and 561 cm -1 ) still existed but the intensity was sharply reduced compared with pure HA. And the intensity of the peak at 3466 cm -1 increased evidently, indicating that OH content increased, which is ascribed to the existence of chitosan. The FTIR spectrum of 130±C-dried 20CS-80HA is similar with that of pure chitosan, which indicates that chitosan in the CS-HA composites was not decomposed at 130±C. Whereas, as shown in Fig. 3(b), there are many absorption peaks between 544{604 cm -1 and 982{1121 cm -1 for 500±C-sintered 20CS-80HA powders, which indicates that the decomposition of chitosan occurred( Figure.8).

Conclusion
The cost of the 12V & 9V power supply is Rs 350 and Rs 300 respectively and the stirrer cost is Rs 300.2. The electrodes anode and cahode can be attached and detached .This is to facilitate the choice of two different electrodes for research and development. Hydroxy apatite was prepared using stainless steel as cathode. The hydroxy apatite has shown characteristic phosphate vibration bands of synthetic hydroxy apatite. XRD pattern of the hydroxyl apatite is comparable that of synthetic hydroxy apatite and the SEM picture has shown rectangular shape hydroxyl apatite crystal on the surface of chitosan film. The TGA studies have shown that 30% of the hydroxy apatite was deposited in the composite film. It is concluded that hydroxyapatite crystals can be synthesized on the surface of chitosan using electrode position technique. These types low voltage power supplies are very useful for nano-biomedical applications for diagnostics.