Micro and Nanosystems - Volume 8, Issue 1, 2016

Conservation practices are aimed to implement minimal, targeted and less invasive treatments. The conservation profession's challenges and best practices are there- fore becoming more global and mobile, especially when dealing with treatments involving temperature (e.g. painting conservation). The near future of heating devices in art conservation will be with mobile, versatile, accurate and cost effective "smart" devices. For these reasons, the design and manufacturing of heating mats for applications in the Cultural Heritage field moved from early concepts mainly based on electrically heated mats towards more accurate thermoelectrical mild heating devices, especially based on nanomaterials. Despite great scientific efforts have been spent in the last years to create more efficient devices for conservation, there is still room for practically implementing them and, moreover, for protecting new concepts by patenting them. To help the scientific community in getting an overview on the patent state of the art on this important sector, the present work is aimed to provide a survey of patents related to nanomaterials-based heaters to be adopted for artworks conservation. Starting from early works, the paper explores recent patents by selecting the domains referred to nanotechnology sec- tor that are mainly relevant for the heating devices field.

Background: Nanoporous copper (NPC) is one of the attractive inexpen- sive nanoporous materials with prospects for many applications such as catalyst, electronics and package. A unique approach to fabricate NPC films and patterned NPC films on various substrates was reported. It will have important implications for fabricating novel microsensors with more complex porous structures from multi- phase alloy families. Methods: The fabrication process includes the electrodeposition of CuZn alloy films in citrate-based electrolytes, followed by subsequent chemical dealloying of CuZn films in HCl solution. Results: The characteristic of NPC films was dependent on the composition and microstructure of precursor CuZn alloy films. A three dimensional bicontinuous NPC structure was formed with pore sizes of 80 to 150 nm after chemical dealloying. The NPC dealloyed from Cu36Zn64 alloy films exhibits high Brunauer-Emmett-Teller (BET) surface area (16.79 m2/g). Conclusion: A novel strategy for the fabrication of nanoporous copper (NPC) films and their arrays on various substrates were developed.

Background: ZnO is an important semiconductor transparent conductive material. The optical and electrical properties can be enhanced by some dopings. This work focus on the effect of Pr doping. Methods: A series of ZnO: Pr films with Pr contents of 0-2.0 at % were deposited by a chemical solution deposition. The deposited films were characterized by X-ray diffraction, field emission scanning electron microscopy, UV-vis and luminescent spectrophotometry, and electrical property measurement. Results: Pr-doping resulted in an obvious variation of optical transmittance in the UV-visible light range, band gap and electrical resistance. The film with a Pr content of 1.5 at.% showed optimal optical and electrical properties. The films also showed a strong band gap emission and two weak emissions related to intrinsic defects of ZnO and defects introduced by the Pr substitution. The emission intensity was related with Pr content. Some other optical parameters were also calculated based on the ultraviolet visible spectra. Conclusion: The optical and electrical properties of ZnO film can be enhanced by small amount of Pr doping. This is of significance to the optical and electrical applications of the Sm-doped ZnO materials.

Aim: The aim of the present investigation is to prepare mefenamic acid nano-particles by desolvation technique using ethanol and isopropanol as desolvating agents. Methodology: To 1% aqueous solution of mefenamic acid the desolvating agent was added intermittently at the rate of 1 ml per every five minutes till the solution become turbid.Then a cross linking agent was added and kept for stirring for a period of 8 hours. Results: Two formulations F1 and F2 were prepared by using ethanol and isopropanol as desolvating agents respectively. The product yield, drug content, entrapment efficiency and loading capacity of F1 was found to be 67.9%, 73.7%, 70.85% and 49.6% respectively. The drug release was found to be 88.57% in a time period of 9hours. The product yield, drug content, entrapment efficiency and loading capacity of F2 was found to be 65%, 53.5%, 92.6% and 61.76% respectively. The drug release was sustained up to 10 hrs with a release rate of 71.47%. Conclusion: Based on the results F1 formulation was considered as the best formulation because of less particle size, greater stability, good entrapment efficiency and high release rate.

Background: Present work deals with the development of a hydrophilic drug encapsulated self healed microparticles. Objective: To develop encapsulated microparticles of Ciprofloxacin, model hydrophilic drug. Method: A modified o/o/w multi emulsion solvent evaporation method was used for the development of Ciprofloxacin encapsulated microparticles. Aluminium hydroxide was used as a healing agent. This method produced encapsulated carrier for hydrophilic drug and sustained release system. Microparticles were evaluated by using 3-level factorial design. Results: The obtained encapsulated microparticles were characterized by FTIR, FESEM and elemental analysis. The variables such as plymer (X1) and aluminium hydroxide (X2) were optimized for the maximum encapsulation efficiency (Y1) and the optimum drug release (Y2) with the help of the response surface methodology (RSM). The RSM predicted that, both X1 and X2 were significant for the Y1 (pvalues- 0.0006 & 0.0023) and Y2 (p- values-0.0003 & <0.0001). An increase in the concentrations of the polymer and aluminium hydroxide increased Y1 and decreased Y2. The obtained optimum value of Y1 and Y2 were 80.86 and 55.34, respectively. Those were well in agreement with the predicted value by RSM. In- vitro drug release study was also performed and data were checked for various kinetic models to confirm the sustained release behaviour of the microparticles. Conclusion: The results showed that concentration of ethylcellulose and aluminium hydroxide greatly influenced the % encapsulation efficiency and drug release. The absence of drug polymer interactions was confirmed by FTIR spectroscopy. In-vitro drug release analysis and its kinetic modelling confirmed the sustained release behaviour of the microparticles.

Background: Nanoparticles have been considered for a wide range of applications both in soluble and insoluble forms. We take an advantage of soluble form of cellulose nanoparticle (CNP) for encapsulation of antibiotic/drug. Methods: The CNP was prepared by micro-emulsion method using organic and oil as the continuous phase and tween-80 as the emulsifying agent. Results: Formation of uniform-sized CNPs was evidenced by scanning and atomic force microscopic studies, measured as the average size of }50 nm. CNP prepared under acidic and neutral conditions did not show improvement for the inhibition of Escherichia coli growth. However, when CNP was alkalinized, it yielded higher antibiotic loading and showed greater rate of bactericidal effect with 3 folds higher efficiency. Increase in the amount of cellulose did not increase the encapsulation rate. Conclusion: This study demonstrates the application antibiotic encapsulated CNP for microbial inhibi- tion and highly applicable for drug delivery system.

Background: Rigidity is a crucial index for the flexible micro-motion mechanism design and research. Most of the researchers studied the correlated characteristics by a selected rigidity analysis method. The rigidity models based on Lagrange equation and work-energy theorem can both fulfill the requirements for common usage. Unfortunately, there is no sufficient contrastive analysis between the two broadly used methods and definite applicable fields for a given method, leading to an ambiguous selection for the rigidity analysis method. Methods: Taking micro displacement amplifier module (MDAM) as example, the relationship of all components' elastic deformations is built up to obtain the accurate motion equation based on pseudo-rigid-body method. In view of energy conversion relationship, two kinds of rigidity model are established separately by Lagrange equation and work-energy theorem. Differences between the two methods are compared. Results: The input displacement and the output displacement are non-linear for MDAM. The changing curves of needed input force according to the output displacement by work-energy theorem and Lagrange equation based methods are almost completely parallel to each other. But there still exist a certain difference, which becomes greater as the input displacement increases. Conclusion: For MDAM, the theoretical rigidity modeling method based on Lagrange equation has taken the components' micro displacement into consideration and it has a higher precision compared with work-energy theorem method.

Background: In this paper, we considered an approach to increase compactness of field-effect heterotransistor with several sources. In this approach, we considered a heterostructure, which consists of a substrate with required type of conductivity (p or n) and epitaxial layer. Required areas of the epitaxial layer have been doped by diffusion or ion implantation to manufacture reverse type of conductivity (n or p). After that we considered an optimized annealing of dopant and/or ra- diation defects to obtain most homogenous distribution of concentration of dopant in doped area and at the same time to decrease quantity of the dopant in the nearest areas. We also introduced an analytical approach for the prognosis of technological process. Methods: Analytical modeling of physical processes is used during manufacturing of a heterotransistor with several sources. Results: We formulate conditions to optimize technological process to decrease dimensions of field-effect heterotransistor with several sources. Conclusion: In this paper, we introduced an approach to decrease dimensions of field-effect heterotransistor with several sources. The approach is based on manufacturing heterostructure, which consists of a substrate with required type of conductivity (p or n) and epitaxial layer. Required areas of the epitaxial layer have been doped by diffusion or ion implantation to manufacture reverse type of conductivity (n or p). After that, we considered an optimized annealing of dopant and/or radiation defects to obtain most homogenous distribution of concentration of dopant in doped area and at the same time to decrease quantity of the dopant in the nearest areas. We also introduced an analytical approach to prognosis mass and heat transport during technological process. Based on the analysis, we formulated conditions to obtain maximal compromise between increasing of homogeneity of distribution of concentration of dopant in doped area and at the same time decreasing quantity of the dopant in the nearest areas.