AN INNOVATIVE STRATEGY FOR THE DELIVERY OF DRUG-LOADED NANO-CARRIERS TO DEMINERALIZED DENTIN SUBSTRATES AND RESIN-DENTIN BONDED INTERFACE

Ph.DDOCTOR OF PHILOSOPH

Effect of antimicrobial agents on biofilm cells and invitro development of resistance in planktonic cells of pseudomonas aeruginosa PA01

97 p.The antimicrobial activity of western as well as eastern drugs against infections caused by P. aeruginosa has become an important area of study in recent years. This study revolves around the use of an effective western drug (Wl), a plant derived chemical or Eastern antibiotic (El) and their combinations against PA01 strain of P. aeruginosa. The synergistic effect of these drugs against biofilm formation was determined using quantification assay technique and their visual evidence was confirmed by Scanning Electron Microscopy. The results of this study indicate that biofilm formation is inhibited in the presence of El even at a sub minimum inhibitory concentration (MIC) value when compared to Wl treated at the same sub MIC value. This study also confirms the presence of moderate synergism between El and Wl in inhibiting biofilm formation. A parallel experiment involved in the development of resistance by planktonic cells of P. aeruginosa against the same antimicrobial agents was carried out. The results showed promising development of resistance at a very high concentration (10 MIC) of Wl within 3 subcultures, at a moderate concentration (5 MIC) of El within 15 subcultures, both of which were treated separately. Resistance to the combination of these drugs (Wl+El) was developed at a concentration of 5 MIC within 13 subcultures.Master of Science (Biomedical Engineering

3D-printed bioreactors for in vitro modeling and analysis

In recent years, three-dimensional (3D) printing has markedly enhanced the functionality of bioreactors by offering the capability of manufacturing intricate architectures, which changes the way of conducting in vitro biomodeling and bioanalysis. As 3D-printing technologies become increasingly mature, the architecture of 3D-printed bioreactors can be tailored to specific applications using different printing approaches to create an optimal environment for bioreactions. Multiple functional components have been combined into a single bioreactor fabricated by 3D-printing, and this fully functional integrated bioreactor outperforms traditional methods. Notably, several 3D-printed bioreactors systems have demonstrated improved performance in tissue engineering and drug screening due to their 3D cell culture microenvironment with precise spatial control and biological compatibility. Moreover, many microbial bioreactors have also been proposed to address the problems concerning pathogen detection, biofouling, and diagnosis of infectious diseases. This review offers a reasonably comprehensive review of 3D-printed bioreactors for in vitro biological applications. We compare the functions of bioreactors fabricated by various 3D-printing modalities and highlight the benefit of 3D-printed bioreactors compared to traditional methods.Nanyang Technological UniversityPublished versionThe authors are thankful for the support by HP-NTU Digital Manufacturing Corporate Lab, Nanyang Technological University, Singapore. The content is solely the responsibility of the authors. This research was conducted in collaboration with HP Inc. and supported/partially supported by the Singapore Government through the Industry Alignment Fund-Industry Collaboration Projects Grant

Powder-based 3D printing for the fabrication of device with micro and mesoscale features

Customized manufacturing of a miniaturized device with micro and mesoscale features is a key requirement of mechanical, electrical, electronic and medical devices. Powder-based 3D-printing processes offer a strong candidate for micromanufacturing due to the wide range of materials, fast production and high accuracy. This study presents a comprehensive review of the powder-based three-dimensional (3D)-printing processes and how these processes impact the creation of devices with micro and mesoscale features. This review also focuses on applications of devices with micro and mesoscale size features that are created by powder-based 3D-printing technology.Nanyang Technological UniversityPublished versionThe authors are thankful for the support by Nanyang Technological University, Singapore

3D printing and 3D-printed electronics: applications and future trends in smart drug delivery devices

Drug delivery devices which can control the release of drugs on demand allow for improved treatment to a patient. These smart drug delivery devices allow for the release of drugs to be turned on and off as needed, thereby increasing the control over the drug concentration within the patient. The addition of electronics to the smart drug delivery devices increases the functionality and applications of these devices. Through the use of 3D printing and 3D-printed electronics, the customizability and functions of such devices can also be greatly increased. With the development in such technologies, the applications of the devices will be improved. In this review paper, the application of 3D-printed electronics and 3D printing in smart drug delivery devices with electronics as well as the future trends of such applications are covered.Published versio

3D printing biocompatible materials with multi jet fusion for bioreactor applications

In the evolving three-dimensional (3D) printing technology, the involvement of different materials in any new 3D printing process necessitates a thorough evaluation of the product's biocompatibility for biomedical application. Here, we examined the ability of Multi Jet Fusion (MJF)-printed PA-12 to support cell proliferation and osteogenesis. Our results show that leachate from MJF-printed PA-12 does not inhibit the growth of L929 fibroblast and MC3T3e1 osteoblast. The substrate supports the attachment and proliferation of both cell types, though not at a level comparable to conventional polystyrene culture plate. Neither plasma treatment, poly-D-lysine, nor collagen coatings narrowed the gap substantially, suggesting the possible influence of other limiting factors. The substrate can also support MC3T3e1 osteogenesis. However, MJF-printed PA-12 exhibits varying ability in supporting the proliferation of different cell types, especially in subsequent passages. While L929's proliferation is comparable from passage-to-passage, MC3T3e1's growth ability is noticeably compromised. Interestingly, our results show that L929 subcultured back to polystyrene plate retains the ability to grow as robustly as those on the conventional plate, suggesting that MJF-printed PA-12 does not permanently impair cell proliferation. In addition, we have shown the successful culture of bacterial Escherichia coli on MJF-printed PA-12. Together, our study demonstrated the potential of MJF-printed PA-12 for biological applications.Published versionThis research was conducted in collaboration with HP Inc. and supported/partially supported by the Singapore Government through the Industry Alignment Fund-Industry Collaboration Projects Grant