Silver Carboxylate-doped Titanium Dioxide-Polydimethylsiloxane Coating decreases Cutibacterium acnes Adherence and Biofilm Formation on Polyether Ether Ketone

Implant surface design has evolved to meet oral rehabilitation challenges in both healthy and compromised bone. For example, to conquer the most common dental implant-related complications, peri-implantitis, and subsequent implant loss, implant surfaces have been modified to introduce desired properties to a dental implant and thus increase the implant success rate and expand their indications. Until now, a diversity of implant surface modifications, including different physical, chemical, and biological techniques, have been applied to a broad range of materials, such as titanium, zirconia, and polyether ether ketone, to achieve these goals. Ideal modifications enhance the interaction between the implant’s surface and its surrounding bone which will facilitate osseointegration while minimizing the bacterial colonization to reduce the risk of biofilm formation. This review article aims to comprehensively discuss currently available implant surface modifications commonly used in implantology in terms of their impact on osseointegration and biofilm formation, which is critical for clinicians to choose the most suitable materials to improve the success and survival of implantation.

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Nanocomposite membrane by incorporating graphene oxide in sulfonated polyether ether ketone for direct methanol fuel cell

Materials Today Proceedings ◽

10.1016/j.matpr.2021.03.614 ◽

2021 ◽

Author(s):

Nuor Sariyan Suhaimin ◽

Juhana Jaafar ◽

Madzlan Aziz ◽

A.F. Ismail ◽

M.H.D. Othman ◽

...

Keyword(s):

Graphene Oxide ◽

Fuel Cell ◽

Direct Methanol Fuel Cell ◽

Nanocomposite Membrane ◽

Polyether Ether Ketone ◽

Sulfonated Polyether Ether Ketone ◽

Direct Methanol ◽

Ether Ketone ◽

Methanol Fuel Cell

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Effect of Titanium Dioxide Nanoparticles on the Expression of Efflux Pump and Quorum-Sensing Genes in MDR Pseudomonas aeruginosa Isolates

Antibiotics ◽

10.3390/antibiotics10060625 ◽

2021 ◽

Vol 10 (6) ◽

pp. 625

Author(s):

Fatma Y. Ahmed ◽

Usama Farghaly Aly ◽

Rehab Mahmoud Abd El-Baky ◽

Nancy G. F. M. Waly

Keyword(s):

Titanium Dioxide ◽

Quorum Sensing ◽

Biofilm Formation ◽

Antimicrobial Agents ◽

Efflux Pump ◽

Titanium Dioxide Nanoparticles ◽

Sol Gel ◽

Efflux Pumps ◽

Antibiofilm Activity ◽

The Impact

Most of the infections caused by multi-drug resistant (MDR) P. aeruginosa strains are extremely difficult to be treated with conventional antibiotics. Biofilm formation and efflux pumps are recognized as the major antibiotic resistance mechanisms in MDR P. aeruginosa. Biofilm formation by P. aeruginosa depends mainly on the cell-to-cell communication quorum-sensing (QS) systems. Titanium dioxide nanoparticles (TDN) have been used as antimicrobial agents against several microorganisms but have not been reported as an anti-QS agent. This study aims to evaluate the impact of titanium dioxide nanoparticles (TDN) on QS and efflux pump genes expression in MDR P. aeruginosa isolates. The antimicrobial susceptibility of 25 P. aeruginosa isolates were performed by Kirby–Bauer disc diffusion. Titanium dioxide nanoparticles (TDN) were prepared by the sol gel method and characterized by different techniques (DLS, HR-TEM, XRD, and FTIR). The expression of efflux pumps in the MDR isolates was detected by the determination of MICs of different antibiotics in the presence and absence of carbonyl cyanide m-chlorophenylhydrazone (CCCP). Biofilm formation and the antibiofilm activity of TDN were determined using the tissue culture plate method. The effects of TDN on the expression of QS genes and efflux pump genes were tested using real-time polymerase chain reaction (RT-PCR). The average size of the TDNs was 64.77 nm. It was found that TDN showed a significant reduction in biofilm formation (96%) and represented superior antibacterial activity against P. aeruginosa strains in comparison to titanium dioxide powder. In addition, the use of TDN alone or in combination with antibiotics resulted in significant downregulation of the efflux pump genes (MexY, MexB, MexA) and QS-regulated genes (lasR, lasI, rhll, rhlR, pqsA, pqsR) in comparison to the untreated isolate. TDN can increase the therapeutic efficacy of traditional antibiotics by affecting efflux pump expression and quorum-sensing genes controlling biofilm production.

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Encapsulation of Capacitive Micromachined Ultrasonic Transducers (CMUTs) for the Acoustic Communication between Medical Implants

Sensors ◽

10.3390/s21020421 ◽

2021 ◽

Vol 21 (2) ◽

pp. 421

Author(s):

Jorge Oevermann ◽

Peter Weber ◽

Steffen H. Tretbar

Keyword(s):

Data Security ◽

Ultrasonic Transducers ◽

Surrounding Tissue ◽

Center Frequency ◽

Medical Implants ◽

Research Groups ◽

Capacitive Micromachined Ultrasonic Transducers ◽

Polyether Ether Ketone ◽

High Bandwidth ◽

Ether Ketone

The aim of this work was to extend conventional medical implants by the possibility of communication between them. For reasons of data security and transmitting distances, this communication should be realized using ultrasound, which is generated and detected by capacitive micromachined ultrasonic transducers (CMUTs). These offer the advantage of an inherent high bandwidth and a high integration capability. To protect the surrounding tissue, it has to be encapsulated. In contrast to previous results of other research groups dealing with the encapsulation of CMUTs, the goal here is to integrate the CMUT into the housing of a medical implant. In this work, CMUTs were designed and fabricated for a center frequency of 2 MHz in water and experimentally tested on their characteristics for operation behind layers of Polyether ether ketone (PEEK) and titanium, two typical materials for the housings of medical implants. It could be shown that with silicone as a coupling layer it is possible to operate a CMUT behind the housing of an implant. Although it changes the characteristics of the CMUT, the setup is found to be well suited for communication between two transducers over a distance of at least 8 cm.

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