Design and Evaluation of a Novel Composite Chitosan-Poly(lactide-co-glycolide) Microsphere Based System for Bone Tissue Engineering Applications

Nearly 60% to 67% of all injuries that occur annually within the US are due to musculoskeletal injuries, with over a million people requiring implants and bone grafting materials to reconstruct bone defects. Our lab has previously developed composite chitosan/nano-hydroxyapatite microsphere based bone grafts that had good compressive strengths, supported bone cell growth and mineralization in vitro, demonstrated biocompatibility and osteoconductivity in a rat calvarial defect model, and when loaded with rhBMP-2 was osteoinductive in a rat muscle pouch model. However, degradation of these scaffolds was very slow which may have limited the amount of new bone formed in vivo. The objectives of this research was to develop a novel composite Chitosan-PLGA microsphere based system prepared via a precipitation method with improved degradation and biological characteristics as compared to plain chitosan (CTS) microspheres. The effect of varying PLGA amounts within the CTS microspheres was evaluated via degradation and biocompatibility studies in addition to physiochemical properties. PLGA particles in the composite CTS-PLGA microspheres segregated to the surface of the microspheres resulting in roughened surface textures. In addition, composite microspheres also had reduced crystallinity resulting in reduced exothermic peak temperatures as seen from XRD and DSC studies; showed increased degradation and better osteoblast attachment as compared to plain CTS microspheres. However, no effect was seen on osteoblast proliferation over a 7 day cell culture period. The results of this study showed that composite CTS-PLGA microsphere based systems have the potential to be used in bone tissue engineering applications and future studies will be aimed at evaluating its potential as a dual drug delivery vehicle

Design of Linearity Improved Low Noise Amplifier using Derivative Superposition

This paper proposes different implementation of derivative superposition technique to improve the linearity of “Low Noise Amplifier” used in the receiver part of communication system. Derivative superposition is proved to be the promising technique for the improvement of linearity of LNA. This paper introduces the DS techniques in different forms by varying W, L or VGS to achieve higher IIP3. Also the results in the implementations are compared to other existing methods. The proposed scheme just not only provides high IIP3 values but it remains stable for a large variations in VGS, which is not the case with other existing techniques

A Study to Assess Knowledge, Attitude and Practice Regarding Tuberculosis among Tuberculosis Patients at Health Centre Nadiad

Tuberculosis is well known contagious infection that spreads though the inhalation of droplet produced by the coughs or sneezes of and infected person. TB usually affect the lungs (pulmonary TB) but can also affect multiple other organs Aims: To Assess the level of Knowledge, Attitude, and Practice among Tuberculosis Patients.  Methodology: A quantitative study was conducted among 100 tuberculosis patients of selected health center Nadiad city by using purposive sampling technique. Data were obtained using knowledge questionnaire (19), Likert’s attitude scale (10) and practice questionnaire (10) with interview technique. Descriptive statics were used to analyze the demographic data.  Result :In this study total 100 tuberculosis patients are participated the result revealed than 14(14%) tuberculosis patients have good knowledge, 66(66%) tuberculosis patients have average knowledge, and 20(20%) tuberculosis patients have poor knowledge, about attitude the shoes that 21(21%) tuberculosis patients have favorable attitude,3(3%) tuberculosis patients have unfavorable attitude and 76(76%) patients have Moderate attitude about practice shows that 20(20%) tuberculosis patients have good practices, 1(1%) tuberculosis patients have poor practices and 79(79%) average practice. The finding tuberculosis patient having good knowledge, Moderate attitudes, and average practice. Conclusion: In this study, the knowledge of patients about TB were found within a low level of perception. Therefore, implementation of health education and awareness program are required to reduce the prevalence of TB

Tending towards Non-fouling: A study of the interaction between proteins and surfaces prepared by radio frequency glow-discharge plasma

Thesis (Ph.D.)--University of Washington, 2019All proteins adsorb irreversibly onto surfaces and often results in denaturation, aggregation and loss of activity. This has serious implications not only for medical devices that are used clinically for the treatment of disease but also for the pharmaceutical industry that deals with handling, storage and delivery of protein-based drugs. In this work, we explore radio frequency (RF) glow-discharge plasma technology as a method of creating non-fouling surfaces. We achieve this through two distinct strategies: a) prepare a highly-reactive surface initiators that could be used to grow HEMA polymer brushes via SI-ARGET ATRP, and b) create novel quasi-zwitterionic or mixed-charged surfaces that closely resemble the chemistry of zwitterionic polymers and therefore are capable of reducing protein adsorption. In addition to preparing non-fouling surfaces to prevent protein adsorption, it is also equally important to properly evaluate the surface-protein interaction. This work explores and describes new protocols involving radiolabeling protein studies, radioimmunoassay and substrate-based direct ELISA to better understand the adsorption, retention and changes in biological activity of the protein once it comes in contact with a biomaterial surface, which further informs the biocompatibility of the surface. Finally, we take the lessons learned from using RF glow-discharge plasma to create non-fouling surfaces and developing new protocols to study surface-protein interaction, and apply it to a real world application where we coat hypodermic syringes with a copolymer of HMDSO and MA to prevent protein adsorption while maintaining syringe lubricity. Overall, this research showcases the ability of RF glow-discharge plasma technology to create a variety of non-fouling surfaces that prevents protein adsorption and can be easily clinically translated for a variety of medical applications

Design and Development of Cost effective Automatic Fertilization System for Small Scale Farm

Most of the developing countries economy largely depends on the agriculture. More than half of the population rely on agriculture related activities for their survival. In spite of dependency on agriculture, the technological development of agricultural work in developing country is not comparable to the countries like Australia or Israel. The main reason behind the lack of development is the small size of farms. Such farmers cannot afford expensive technology available in the market due to limited profit margins. The report describes an autonomous fertilization system that takes care of the fertilization requirements of the small scale farms at affordable rates. The system is divided in two parts namely User Interface and Control System. The user interface is designed using the state of the art Raspberry Pi board and a touch screen LCD. The control system is developed using the Arduino platform and can control five fertilizers at a time. The output of the system is the mix of the fertilizer, which is forced into the drip irrigation system of the farm. The system has built in data for the fertilization requirement for important crops and vegetation. The system also facilitates the customize fertilization requirements to be added in the system as per the user requirements

In-vitro Study on Genotoxicity of Green Synthesized Silver Nanoparticles

The wide use of metal nanoparticles has raised the concern of their release in the environment and their biological safety. The use of silver nanoparticles (Ag NPs) as effective antimicrobial agent is also questioned due to the resistance developed by pathogens and the biosafety for the host. The genotoxicity caused by such particles need to be assessed to ensure that they are safe to use. In this study, green synthesized Ag NPs were used and the biosafety in terms of genotoxicity was evaluated by in vitro Chromosome aberration (CA) assay using short-term cultures of human peripheral blood. The physicochemical parameters of these Ag NPs were studied for stability in nano form. The transmission electron microscopy (TEM) and energy-dispersive spectroscopy (EDS) were carried out. The dynamic light scattering and zeta potential measurements revealed stable nano particles. The UV visible & fluorescence spectroscopy for binding affinity of Ag NPs did not suggest significant DNA interaction. The exposure of whole blood cultures to Ag NPs for 24 h showed dose dependent increase in frequency of CA per cell at 350, 650 and 1000 μL (P = NS, P < 0.05 and P < 0.001 respectively). Our study demonstrates that genotoxicity of Ag NPs can be reduced by the use of green synthesized Ag NPs at low dose exposure, which will guide selecting right concentrations of NP for further in vivo studies, and future applications

Effect of molecular weight of chitosan degraded by microwave irradiation on lyophilized scaffold for bone tissue engineering applications

Chitosan (CTS) is biocompatible, biodegradable, and can be formed into 3D porous structures for bone tissue engineering applications. Although studies have reported on the effects of molecular weight (MW) on CTS physicochemical properties, studies evaluating CTS biological property relationships often do not account for MW that confounds interpretation of study results. The aim of this study was to evaluate the effect of MW on CTS physicochemical and biological properties. CTS materials were treated for 6, 18, and 30 min by microwave irradiation to decrease MW without affecting deacetylation (DDA). Materials were evaluated for crystallinity using X-ray diffraction, thermal degradation using differential scanning calorimetry, water content, swelling ratio, and in vitro compatibility using Saos-2. Results showed that microwave treatments did not affect DDA but decreased MW and swelling ratio by 45.78% and 36.75%, respectively, after 30 min of microwave treatment. Microwave-treated CTS showed reduced or no crystalline peaks. Initial increase in exothermic peak temperatures with short (6 min) microwave treatment times were followed by a decrease with longer (18 and 30 min) treatment times. Cell growth over 7 days on samples was proportional to MW with the number of cells being 62% higher on CTS with the highest MW (3.71 ± 0.25 × 105 g/mol) when compared with the lower MW CTS (2.38 ± 0.12 × 105 g/mol). These results demonstrate the importance of MW of CTS to both its physicochemical characteristics and biological properties, providing researchers with another tool for the modulation and optimization of CTS for different biomedical applications. © 2011 Wiley Periodicals, Inc

Balancing mechanical strength with bioactivity in chitosan-calcium phosphate 3D microsphere scaffolds for bone tissue engineering: Air- vs. freeze-drying processes

The objective of this study was to evaluate the potential benefit of 3D composite scaffolds composed of chitosan and calcium phosphate for bone tissue engineering. Additionally, incorporation of mechanically weak lyophilized microspheres within those air-dried (AD) was considered for enhanced bioactivity. AD microsphere, alone, and air- and freeze-dried microsphere (FDAD) 3D scaffolds were evaluated in vitro using a 28-day osteogenic culture model with the Saos-2 cell line. Mechanical testing, quantitative microscopy, and lysozyme-driven enzymatic degradation of the scaffolds were also studied. FDAD scaffold showed a higher concentration (p \u3c 0.01) in cells per scaffold mass vs. AD constructs. Collagen was ∼31% greater (p \u3c 0.01) on FDAD compared to AD scaffolds not evident in microscopy of microsphere surfaces. Alternatively, AD scaffolds demonstrated a superior threefold increase in compressive strength over FDAD (12 vs. 4 MPa) with minimal degradation. Inclusion of FD spheres within the FDAD scaffolds allowed increased cellular activity through improved seeding, proliferation, and extracellular matrix production (as collagen), although mechanical strength was sacrificed through introduction of the less stiff, porous FD spheres. © 2013 Copyright Taylor and Francis Group, LLC