Tag Archives: Albert Kim

Smart dental implant resists bacterial growth and generates own electricity

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A “smart” dental implant could improve upon current devices by employing biofilm-resisting nanoparticles and a light powered by biomechanical forces to promote health of the surrounding gum tissue. (Image: Courtesy of Albert Kim)

A September 9, 2021 news item on ScienceDaily announces research into ‘smart’ dental implants,

More than 3 million people in America have dental implants, used to replace a tooth lost to decay, gum disease, or injury. Implants represent a leap of progress over dentures or bridges, fitting much more securely and designed to last 20 years or more.

But often implants fall short of that expectation, instead needing replacement in five to 10 years due to local inflammation or gum disease, necessitating a repeat of a costly and invasive procedure for patients.

“We wanted to address this issue, and so we came up with an innovative new implant,” says Geelsu Hwang, an assistant professor in the University of Pennsylvania School of Dental Medicine, who has a background in engineering that he brings to his research on oral health issues.

The novel implant would implement two key technologies, Hwang says. One is a nanoparticle-infused material that resists bacterial colonization. And the second is an embedded light source to conduct phototherapy, powered by the natural motions of the mouth, such as chewing or toothbrushing. In a paper in the journal ACS Applied Materials & Interfaces and a 2020 paper in the journal Advanced Healthcare Materials, Hwang and colleagues lay out their platform, which could one day be integrated not only into dental implants but other technologies, such as joint replacements, as well.

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A September 9, 2021 University of Pennsylvania news release (also on EurekAlert), which originated the news item, provides more technical details about the proposed technology,

“Phototherapy can address a diverse set of health issues,” says Hwang. “But once a biomaterial is implanted, it’s not practical to replace or recharge a battery. We are using a piezoelectric material, which can generate electrical power from natural oral motions to supply a light that can conduct phototherapy, and we find that it can successfully protect gingival tissue from bacterial challenge.”

In the paper, the material the researchers explored was barium titanate (BTO), which has piezoelectric properties that are leveraged in applications such as capacitators and transistors, but has not yet been explored as a foundation for anti-infectious implantable biomaterials. To test its potential as the foundation for a dental implant, the team first used discs embedded with nanoparticles of BTO and exposed them to Streptococcus mutans, a primary component of the bacterial biofilm responsible for tooth decay commonly known as dental plaque. They found that the discs resisted biofilm formation in a dose-dependent manner. Discs with higher concentrations of BTO were better at preventing biofilms from binding.

While earlier studies had suggested that BTO might kill bacteria outright using reactive oxygen species generated by light-catalyzed or electric polarization reactions, Hwang and colleagues did not find this to be the case due to the short-lived efficacy and off-target effects of these approaches. Instead, the material generates enhanced negative surface charge that repels the negatively charged cell walls of bacteria. It’s likely that this repulsion effect would be long-lasting, the researchers say.

“We wanted an implant material that could resist bacterial growth for a long time because bacterial challenges are not a one-time threat,” Hwang says.

The power-generating property of the material was sustained and in tests over time the material did not leach. It also demonstrated a level of mechanical strength comparable to other materials used in dental applications.

Finally, the material did not harm normal gingival tissue in the researchers’ experiments, supporting the idea that this could be used without ill effect in the mouth.

The technology is a finalist in the Science Center’s research accelerator program, the QED Proof-of-Concept program. As one of 12 finalists, Hwang and colleagues will receive guidance from experts in commercialization. If the project advances to be one of three finalists, the group has the potential to receive up to $200,000 in funding.

In future work, the team hopes to continue to refine the “smart” dental implant system, testing new material types and perhaps even using assymetric properties on each side of the implant components, one that encourages tissue integration on the side facing the gums and one that resists bacterial formation on the side facing the rest of the mouth.

“We hope to further develop the implant system and eventually see it commercialized so it can be used in the dental field,” Hwang says.

Here’s a link to and a citation for the paper,

Bimodal Nanocomposite Platform with Antibiofilm and Self-Powering Functionalities for Biomedical Applications by Atul Dhall, Sayemul Islam, Moonchul Park, Yu Zhang, Albert Kim, and Geelsu Hwang. ACS Appl. Mater. Interfaces 2021, 13, 34, 40379–40391 DOI: https://doi.org/10.1021/acsami.1c11791 Publication Date:August 18, 2021 Copyright © 2021 American Chemical Society

This paper is behind a paywall.

The work from 2020, mentioned in the news release, laid groundwork for the latest paper.

Human Oral Motion-Powered Smart Dental Implant (SDI) for In Situ Ambulatory Photo-biomodulation Therapy by Moonchul Park, Sayemul Islam, Hye-Eun Kim, Jonathan Korosto, Markus B. Blatz, Geelsu Hwang, and Albert Kim. Adv. Healthcare Mater. 2020, 9, 2000658 DOI: 10.1002/adhm.202000658 First published: 01 July 2020 © 2020 WILEY-VCH Verlag GmbH & Co. KGaA, WeinheimHuman

This paper is behind a paywall.

Music can recharge sensors in your body

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According to a Jan.26, 2012 news item written by Emil Venere at Purdue University and posted on Nanowerk, researchers have found a new way to recharge batteries in new medical sensors that could be implanted in individuals stricken with aneurysms or bladder incontinence due to paralysis. From the news item,

“You would only need to do this for a couple of minutes every hour or so to monitor either blood pressure or pressure of urine in the bladder,” Ziaie [Babak Ziaie, a Purdue University professor of electrical and computer engineering and biomedical engineering] said. “It doesn’t take long to do the measurement.”

Findings are detailed in a paper (“A Novel Electromechanical Interrogation Scheme for Implantable Passive Transponders”) to be presented during the IEEE [Institute of Electrical and Electronics Engineers] MEMS [Micro Electro Mechanical Systems] 2012 conference, which will be Jan. 29 to Feb. 2 in Paris. The paper was written by doctoral student Albert Kim, research scientist Teimour Maleki and Ziaie.

“This paper demonstrates the feasibility of the concept,” he said.

As you may have guessed from that last line, this hasn’t been tried on people. According to the news item, the concept was tested using a water-filled balloon.

I checked out Venere’s Jan. 26, 2012 news release on the Purdue University website and am excerpting a few details about how these medical sensors work,

The sensor is capable of monitoring pressure in the urinary bladder and in the sack of a blood vessel damaged by an aneurism. Such a technology could be used in a system for treating incontinence in people with paralysis by checking bladder pressure and stimulating the spinal cord to close the sphincter that controls urine flow from the bladder. More immediately, it could be used to diagnose incontinence. The conventional diagnostic method now is to insert a probe with a catheter, which must be in place for several hours while the patient remains at the hospital.

The writer goes on to describe some of the reasons for why this new technology is being pursued,

“A wireless implantable device could be inserted and left in place, allowing the patient to go home while the pressure is monitored,” Ziaie said.

The new technology offers potential benefits over conventional implantable devices, which either use batteries or receive power through a property called inductance, which uses coils on the device and an external transmitter. Both approaches have downsides. Batteries have to be replaced periodically, and data are difficult to retrieve from devices that use inductance; coils on the implanted device and an external receiver must be lined up precisely, and they can only be about a centimeter apart.

The following image is  the researchers’ new sensor, balanced on a coin,

Researchers have created a new type of miniature pressure sensor, shown here, designed to be implanted in the body. Acoustic waves from music or plain tones drive a vibrating device called a cantilever, generating a charge to power the sensor. (Birck Nanotechnology Center, Purdue University)

I found the description of how the cantilever works and can be recharged quite interesting,

The heart of the sensor is a vibrating cantilever, a thin beam attached at one end like a miniature diving board. Music within a certain range of frequencies, from 200-500 hertz, causes the cantilever to vibrate, generating electricity and storing a charge in a capacitor …

The cantilever beam is made from a ceramic material called lead zirconate titanate, or PZT, which is piezoelectric, meaning it generates electricity when compressed. The sensor is about 2 centimeters long …

A receiver that picks up the data from the sensor could be placed several inches from the patient. Playing tones within a certain frequency range also can be used instead of music.

“But a plain tone is a very annoying sound,” Ziaie said. “We thought it would be novel and also more aesthetically pleasing to use music.”

Researchers experimented with four types of music: rap, blues, jazz and rock.

“Rap is the best because it contains a lot of low frequency sound, notably the bass,” Ziaie said.

“The music reaches the correct frequency only at certain times, for example, when there is a strong bass component,” he said. “The acoustic energy from the music can pass through body tissue, causing the cantilever to vibrate.”

When the frequency falls outside of the proper range, the cantilever stops vibrating, automatically sending the electrical charge to the sensor, which takes a pressure reading and transmits data as radio signals. Because the frequency is continually changing according to the rhythm of a musical composition, the sensor can be induced to repeatedly alternate intervals of storing charge and transmitting data.

“You would only need to do this for a couple of minutes every hour or so to monitor either blood pressure or pressure of urine in the bladder,” Ziaie said. “It doesn’t take long to do the measurement.”

It’s usually a long time from testing a concept (in this case, on a water balloon) to bringing a product to the marketplace. In the meantime, I wonder if this concept will work in the ‘wild’ where people are exposed to rap music accidentally or they like to listen to it themselves, all day long, or they loathe rap music and don’t want to listen for a few minutes every hour.

Finally, I have some special appreciation for Venere as he very neatly explained terms I’ve seen many times but for which I’ve only been able to find complicated definitions. Thank you, Mr. Venere and for a very clear description of this technology.