Connect with us

Published

on

By Pooja Toshniwal Paharia Apr 30 2024 Reviewed by Lily Ramsey, LLM

In a recent study published in Scientific Advances, researchers created a bioresorbable, cordless, passive sensor that monitors pH locally and detects stomach leakage early on.

Study:  Bioresorbable, wireless, passive sensors for continuous pH measurements and early detection of gastric leakage . Image Credit: sasirin pamai/Shutterstock.com Background

Biomarkers surrounding internal organs can give postoperative information, such as intra-abdominal pH changes following stomach surgery. Traditional radiological procedures are neither biocompatible nor appropriate for temporary implants.

An implanted, wireless pH sensor might be the most efficient method for rapid detection. Recent improvements in response-generating hydrogels show promise for point-of-care medical diagnostics.

Incorporating pH-responsive hydrogels into wireless electrical devices may be an effective engineering strategy. About the study

In the present study, researchers developed a bioresorbable device for early detection of anastomotic leaks following gastric surgery, using passive analog-type wireless communications to ensure rapid reaction times and early clinical outcomes.

A pH-sensitive hydrogel functioned as the transducer, connecting to a mechanically designed inductor-capacitor circuit, enabling wireless reading. The hydrogel is functionalized with pH-responsive-type tertiary amines, resulting in specific, mechanically durable, biodegradable, and pH-responsive hydrogels.

This material provided supporting matrices for inductor-capacitor (LC) resonance circuits, rapidly converting dimensional alterations into resonant frequency shifts in magnitudes measured precisely by inductive connections to external reading devices.

Mechanics models help inform decisions on the optimum hydrogel and circuit component geometries, particularly that of the sensor inductor. Systematic investigations in animals and device setups in vitro confirm the device's continuous pH monitoring ability.

The researchers established the technology's biocompatibility and bioresorbability by histological examinations, complete blood count (CBC) testing, and serum chemistry. Related StoriesEngineered peptides show promise in cancer immunotherapyResearchers elucidate how gene mutation mechanism causes autismStudy finds high microplastic levels in Mediterranean fish despite low chemical contaminants

The fabrication technique included combining poly(ethylene glycol)diacrylate (PEGDA), poly[2- (diisopropylamine)ethyl methacrylate (PDPAEMA), and 2,2- dimethoxy- 2- phenyl acetophenone (DMPA), curing the hydrogel with UV radiation, and laser cutting Zn foils to form an inductor with spiral coils.

Molten bioresorbable wax was infused into the channels, resulting in a homogeneous, electrically insulating layer. The location of the inductor and capacitor was determined by demolding the wax-coated Zn coil and casting the pH-responsive hydrogel prepolymer.

The researchers defined the capacitor's top and bottom electrodes by laser-cutting Zn foil discs. The reading system consists of a VNA and a single-turn coil. Setting the VNA to reflective mode allows for measurements of the actual and virtual portions of the S-matrix element S11.

The pH of all buffer solutions and biofluids is calibrated and verified with an ion-sensitive field-effect transistor pH meter.

The study included adult male Lewis rats aged 14-16 weeks acclimatized for up to 7 days before surgery. During the implantation procedure, the rats were given general anesthesia via inhaled isoflurane vapor.

The team conducted functional tests on euthanized pigs and several rat models. They obtained blood samples four, six, and twelve weeks after implantation and preserved the explanted organs in neutral-buffered formalin for histological research. Results

The platform monitors gastric fluid leakage during the crucial risk phase after laparoscopic sleeve gastrectomy (LSG). It uses wireless readout coils to measure the sensor circuit's resonance frequency, which is affected by the surrounding biological fluid acidity.

Any leaking stomach contents (pH 1.0 to 3.0) infiltrate the hydrogel, causing edema and sudden resonant frequency (FS) shift, necessitating surgical intervention. The device degrades spontaneously following the healing time, reducing the dangers and expenses associated with future extraction operations.

The sensitive part of the monitoring device is the pH-reactive hydrogel enclosed in an inductor with a serpentine spiral shape.

The hydrogel degrades in biological fluids by hydrolyzing the constituent ester groups or ether cleavage during oxidation, rendering it water-soluble, harmless, and removable from the human body. The inductor design seeks to reduce mechanical compliance while maintaining low resistance and a high quality (Q) factor.

Performance assessments centered on the wireless readout showed that the sensor could achieve accuracy across a wide range of approximately 3.0 cm through the air and 2.0 cm through fat and lean tissues. 

Non-destructive medical imaging technologies, such as ultrasonography, can aid in determining the precise placement of deployed sensors during routine bedside examinations. Additional trials show that the sensor can respond to acid injected up to 6.0 cm away within an hour.  

The researchers used small and large animal models to test stability and appropriate functioning during a seven-day therapeutically relevant timeframe.

The study shows that implantation of a pH sensor in rat models does not harm organ tissues or produce inflammatory responses such as immune cell aggregation.

The study presents a wireless device for postoperative monitoring of gastric leakage and biosorption following surgery. The sensor, which causes water and hydrogen ion diffusion into a biodegradable hydrogel, enables volumetric expansion and inductance changes.

These changes can be wirelessly sensed as shifts in the resonance frequency and recorded via near-field coupling to an external reader. Mechanical models help guide design decisions, and potential enhancements include increasing wireless sensing range and merging tethered and deployable hydrogel device designs. Journal reference:

Shuo Li et al. (2024) Bioresorbable, wireless, passive sensors for continuous pH measurements and early detection of gastric leakage. Sci. Adv. 2024, 10, eadj0268, doi: 10.1126/sciadv.adj0268. https://www.science.org/doi/10.1126/sciadv.adj0268

Continue Reading

Sports

Oilers ‘make it stressful,’ defeat Canucks in G7

Published

on

By

Oilers 'make it stressful,' defeat Canucks in G7

With a slightly fading voice and a ticket to the Western Conference final in hand, Connor McDavid said what many were surely thinking about his team’s latest performance.

“We know how to make it stressful,” McDavid told Sportsnet.

McDavid and the Edmonton Oilers saw their three-goal lead come under threat late in the third period with the Vancouver Canucks scoring twice. Even with those goals, the Oilers held firm in a 3-2 win Monday in Game 7 of the Western Conference final.

Now, the Oilers will travel to Dallas where they will face the Dallas Stars in the conference final for the right to advance to the Stanley Cup final. For the Oilers, this will be their second trip to the conference final in the last three years while the Stars are making a consecutive appearance.

Three second-period goals from Cody Ceci, Zach Hyman and Ryan Nugent-Hopkins meant the Oilers were 20 minutes away from the conference final.

Then, their lead was cut to 3-1 on a goal from Conor Garland with less than nine minutes left. Nearly four minutes later, Filip Hronek scored to cut the Oilers lead to 3-2 and give the Canucks new life with 4:36 remaining in the third.

Oilers coach Kris Knoblauch immediately called a timeout after Hronek’s goal, a decision that McDavid praised for a few reasons.

“I thought it was a great timeout,” McDavid told reporters. “Even Darnell (Nurse) he was getting guys together and showing great leadership. That’s what he is, a great leader. He’s big in this room and showed great leadership there bringing everybody in. … It just settled everyone down and we were able to close it out.”

Another aspect of that reset was it appeared to have played a role in the Oilers preventing what could have been another comeback. It started in Game 1 when the Oilers lost a three-goal lead to lose 5-4, which began a trend of the Canucks winning their three games after previously trailing.

Except that didn’t happen Monday.

The Canucks not only struggled to setup in the Oilers’ zone following the timeout, but they failed to get a clean look on net. Dylan Holloway blocked Nikita Zadorov‘s shot while Leon Draisaitl used his stick to disrupt passing lanes before Hyman blocked Hronek’s final attempt with three second left.

“They’re a good team, you give them any life, they’re going to push,” Nugent-Hopkins said. “I thought we did a great job of sticking with it, staying composed and not imploding and having each other’s backs.”

For the Canucks, losing Game 7 brings an end to a season that initially started with questions and finished being one of the best campaigns in the club’s history.

The decision to fire Bruce Boudreau in January 2023 and hire Rick Tocchet saw the Canucks go through growing pains as part of a transition that saw them win 20 of the 36 games in which Tocchet was in charge last season.

Tocchet’s teachings carried over into the start of a 2023-24 season that saw the Canucks go from early season surprise to a team that could seriously contend for a Stanley Cup. After splitting the first two games of their quarterfinal series against the Predators, all but one of the Canucks’ remaining playoff games were decided by a goal.

“S—. I mean, I’ve lost games in junior that I still stay up at night and think about,” Garland said. “This will hurt for a long time.”

Being able to tie the game after falling behind early comes as the Canucks were without star winger Brock Boeser. The 27-year-old, who led the team in goals and points, was ruled out for Game 7 after it was reported Sunday that a blood-clotting issue was found in his leg.

Losing Boeser on the eve of one of the biggest games in franchise history came in a postseason that saw the Canucks play all but one game without star goaltender and Vezina Trophy finalist Thatcher Demko, who was injured after Game 1.

As was the case with Demko, the Canucks said after the game they didn’t see losing Boeser as an excuse for why they lost.

“I don’t feel sorry for us. I feel sorry for Brock,” Miller said. “He’s worked his ass off all year long and had a career year. With how far he’s come as a player since I’ve been here. Being out there, blocking shots with the goalie pulled. He’s that type of player. For him not to be out there today must suck for him and I feel for him. It’s not about us right now. It’s about being there for him.”

Continue Reading

Sports

Sweden stays perfect; Britain, Poland relegated

Published

on

By

Sweden stays perfect; Britain, Poland relegated

PRAGUE — Sweden beat France 3-1 to preserve a perfect record at the ice hockey world championship and clinch a group top spot Monday.

Lucas Raymond scored and added an assist, defenseman Erik Karlsson scored his fourth goal of the tournament on a power play, and Andre Burakovsky had an empty net goal for Sweden to record a sixth win in six Group B matches.

Charles Bertrand scored the lone goal for France, which is seventh.

In Group A, Norway beat last-place Britain 5-2 and was sixth.

The Brits remain pointless with a game to go in the group stage and are relegated after one year in the top division.

Later Monday, Hannes Bjorninen and Rasmus Rissanen scored 1:37 apart in the final period to help Finland pass Denmark 3-1, a result that keep the Finns in contention for fourth place in the group and a playoff spot.

Finland has three more points than Austria with both to play one more game. In their encounter, Austria defeated Finland 3-2 and would advance if they are tied on points.

In Group B, Kazakhstan rallied past newcomer Poland 3-1. Poland qualified for the worlds after 22 years only to be immediately relegated after collecting only one point. Kazakhstan moved to sixth with six points.

Continue Reading

World

Iranian protesters express ‘joy’ over death of President Ebrahim Raisi in helicopter crash

Published

on

By

Iranian protesters express 'joy' over death of President Ebrahim Raisi in helicopter crash

Iranian protesters have expressed “joy” over the death of President Ebrahim Raisi who was dubbed the “Butcher of Tehran”.

Speaking to Sky News’ The World With Yalda Hakim, three Iranians spoke on the condition of anonymity over fears of being tracked down by the country’s regime.

A protest leader – who is currently in hiding – suggested Sunday’s crash, that also killed Iran’s foreign minister, was “pre-planned”.

Please use Chrome browser for a more accessible video player

Rescuers reach helicopter crash site

“We may not be across everything, but it’s been a known fact for a long time that Raisi was a serious contender to replace the Supreme Leader Khamenei, and perhaps some didn’t want that to happen.

“But all in all, this was very good news.

“All I can say is that the only thing that has made me truly happy over the past five years has been the news of Raisi’s death.”

Iranian President Ebrahim Raisi speaks during a meeting in Azerbaijan on Sunday. Pic: Reuters
Image:
Ebrahim Raisi. Pic: Reuters

Mr Raisi’s time in charge included major protests over Mahsa Amini – the woman who died after she was arrested for allegedly not wearing her hijab properly.

The US said Mr Raisi had “blood on his hands” as the former hardline cleric was “a brutal participant in the repression of the Iranian people for nearly four decades”.

Iran also took the unprecedented decision in April to launch a drone and missile attack on Israel.

Please use Chrome browser for a more accessible video player

Iranians mourn death of president

A 23-year-old student – who has taken part in a number of protests – said: “The death of Raisi has made the people of Iran very happy.

“On the streets, people were handing out sweets, they were smiling at each other.

“That’s the extent to which this news has spread joy amongst people.”

Read more:
Who was hardliner Iranian president Ebrahim Raisi?
‘Butcher of Tehran’ had fearsome reputation – many will fear instability

Raisi’s death may not mean immediate change for Iran


Dominic Waghorn - Diplomatic editor

Dominic Waghorn

International affairs editor

@DominicWaghorn

From the voices speaking out on The World with Yalda Hakim from inside Iran there was a sense of celebration on the eve of the funeral of their dead president but also a sense of realism.

One dead president the fall of a regime does not make. That is the bitter truth for those brave Iranians speaking out and the millions of Iranians they represent. They detest a man who presided over a brutal crackdown on protests that saw hundreds killed on the streets, and thousands incarcerated, tortured, raped or killed after their arbitrary arrest.

But there are reasons for Iranians to find some hope in the news of the president’s death.

Analysts have compared the Iranian theocratic Islamic regime to the Soviet Union in its dying days.

It is ideologically bankrupt. Its people do not believe in what it stands for anymore. It is morally bankrupt too, after the brutal repression that crushed the Women, Life and Freedom protests. But it remains powerful, with many people on its payroll and it is hard to predict how or when it falls.

Iran’s people want one thing though, and its government the opposite, and that ultimately is impossible to sustain.

Raisi had a unique skill set. He was both a zealous idealogue and an ex-judge. A man who understood how both Iran’s judiciary and presidency works. He combined a passionate belief in the Iranian revolution with an expertise in how its regime operated.

It has been said many times in the last 24 hours that Ayatollah Khamenei, Iran’s supreme leader, will find another hardliner to replace him. There are plenty more where he came from.

But no one with quite his skills and expertise. That may not be important immediately but at the moment of greatest danger in the not so distant future when Khamenei dies, it could make all the difference.

With no anointed successor, the supreme leader’s passing could usher in a period of instability and weakness for the regime. Raisi was seen as a potential successor but also a powerful stabilising force as president in that perilous hiatus, someone who could hold the ring while the new order is established and power struggles fought out.

Raisi’s death may well not mean immediate change for Iran but it could ultimately hasten its end.

A housewife, who was beaten up for taking parting in the “Woman, Life, Protest” movements, said: “The public hatred towards this regime is not a secret to anyone.

“Raisi’s death proved that the pain that this inflicted on our people will one day hit them back.

“My personal reaction to the death of Raisi… I was very happy.

“I’m not upset at all. Even though I never wish death on anyone, but this man, not only did he not do anything for our nation, but he ordered the death of countless young innocent people.”

Following news of Mr Raisi’s death, US State department spokesperson Matt Miller said the Iranian president “was involved in numerous horrific human rights abuses, including playing a key role in the extra judicial killing of thousands of political prisoners in 1988”.

“Some of the worst human rights abuses occurred during his tenure as president, especially the human rights abuses against the women and girls of Iran,” he added.

The US approach to Iran “will not change” because of Mr Raisi’s death, Mr Miller said.

Continue Reading

Trending