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Archive for the ‘Uncategorized’ Category


Extraordinary Breakthrough in Artificial Eyes and Artificial Muscle Technology

Reporter: Irina Robu, PhD

Metalens, flat surface that use nanostructures to focus light promise to transform optics by replacing the bulky, curved lenses presently used in optical devices with a simple, flat surface.

Scientists at the Harvard John A. Paulson School of Engineering and Applied Sciences designed metalens who are mainly focused on light and minimizes spherical aberrations through a dense pattern of nanostructures, since the information density in each lens will be high due to nanostructures being small.

According to Federico Capasso, “This demonstrates the feasibility of embedded optical zoom and auto focus for a wide range of applications, including cell phone cameras, eyeglasses, and virtual and augmented reality hardware. It also shows the possibility of future optical microscopes, which operate fully electronically and can correct many aberrations simultaneously.”

However, when scientists tried to scale up the lens, the file size of the design alone would balloon up to gigabytes or even terabytes. And as a result, create a new algorithm in order to shrivel the file size to make the metalens flawless with the innovation currently used to create integrated circuits. Afterward, scientists follow the large metalens to an artificial muscle without conceding its ability to focus light. In the human eye, the lens is enclosed by ciliary muscle, which stretches or compresses the lens, changing its shape to adjust its focal length. Scientists at that moment choose a thin, transparent dielectric elastomer with low to attach to the lens.

Within the experiment, when the voltage is applied to elastomers, it stretches, the position of nanopillars on the surface of the lens shift. The scientists as a result show that the lens can focus instantaneous, control abnormalities triggered by astigmatisms, and achieve image shift. Since the adaptive metalens is flat, you can correct those deviations and assimilate diverse optical capabilities onto a single plane of control.

SOURCE

https://news.harvard.edu/gazette/story/2018/02/researchers-combine-artificial-eye-and-artificial-muscle

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3D Print Shape-Shifting Smart Gel

Reporter: Irina Robu, PhD

Hydrogel scaffolds that mimic the native extracellular matrix (ECM) environment play a crucial role in tissue engineering and they are ubiquitously in our lives, including in contact lenses, diapers and the human body.

Researchers at Rutgers have invented a printing method for a smart gel that can be used to create materials for transporting small molecules like drugs to human organs. The approach includes printing a 3D object with a hydrogel that changes shape over time when temperature changes. The potential of the smart hydrogels could be to create a new are of soft robotics and enable new applications in flexible sensors and actuators, biomedical devices and platforms or scaffolds for cells to grow.

Rutgers engineers operated with a hydrogel that has been in use for decades in devices that generate motion and biomedical applications such as scaffolds for cells to grow on. The engineers learned how to precisely control hydrogel growth and shrinkage. In temperatures below 32 degrees Celsius, the hydrogel absorbs more water and swells in size. When temperatures exceed 32 degrees Celsius, the hydrogel begins to expel water and shrinks, the study showed.

According to the Rutgers engineers, the objects they can produce with the hydrogel range from the width of a human hair to several millimeters long. The engineers also showed that they can grow one area of a 3D-printed object by changing temperatures.

Source

https://news.rutgers.edu/rutgers-engineers-3d-print-shape-shifting-smart-gel/20180131

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A magnetic wire could replace the lottery of cancer blood tests

Reporter: Irina Robu, PhD

Stanford University scientists developed a magnetic wire which doctors can use to detect cancer before symptoms are detected in patients. The device is threaded into a vein, screens for the disease by attracting scarce and hard to capture tumor cells just like a magnet. The wire would be predominantly valuable to detect ‘silent killers’ such as pancreatic, ovarian and kidney cancer where symptoms only seem in the late stages when it has spread too far to treat. The magnetic wire can save thousands of lives by catching the disease at a time when drugs would be effective. Cells that have broken off a tumor to wander the bloodstream easily can assist as cancer biomarkers signaling the presence of the disease.

Dr. Gambhir’s team published the results in Nature Biomedical Engineering which described how using a wire that has magnetic nano-particles engineered to stick to cancerous cells. The original experiment is on pigs, which are structurally alike to humans and suffer from the same genetic malfunctions that cause cancer. The wire captured 10 to 80 times more tumor cells and was placed in a vein near the pig’s ear which can be removed from and the cells can be used for analysis. In real standings it chosen up 500 to 5,000 more cancerous cells than normal blood samples.

The circulating tumor cells were magnetized with nanoparticles containing an antibody that latch onto them. When attached, the cell carries the tiny magnet around with it and flows past the wire to veer from its regular path in the bloodstream and stick to the wire.  Professor Gambhir hopes that this approach will enrich detection capability and give insight how circulating tumor cells are and how early on they exist once the cancer is present. Once the technology is accepted for humans, the goal is to mature it into a multi-pronged tool that will increase detection, diagnosis, treatment and evaluation of cancer therapy.

It can also be used to gather genetic information about tumors located in places from where it’s hard to take biopsies.

Source

http://med.stanford.edu/news/all-news/2018/07/magnetized-wire-could-be-used-to-detect-cancer-in-people.html

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Print’s Technology Used to Help Produce 3D Printed Glass Molds for Droplet Microfluidic Chips

Reporter: Irina Robu, PhD

Scientists from Leibniz HKI, Friedrich Schiller University, the Ilmenau University of Technology, FEMTOprint  and the Fraunhofer Institute for Applied Optics and Precision Engineering fabricated 3D polydimethylsiloxane (PDMS) chips for droplet microfluidics by using FEMTOprint’s innovative glass technology to make 3D printed glass molds. The 3D printed glass mold can pack 192 nozzles into a design that’s 25 mm long and 4 mm wide, including all inlets and outlets, which produce monodisperse droplets of 70 µm. It’s also easy to scale this structure so it is capable of holding 1,000 nozzles in a 6.5 cm structure.

FEMTOprint’s direct writing process makes it possible to produce microfluidic designs with diverse levels, continuously changing heights, and complex 3D shapes, along with sub-micrometric resolution. 3D printed glass molds are used to combine the replication and ease of production that soft lithography is capable of with the advantages of high-resolution prototyping. Moreover, it can facilitate fabrication of multilevel structures even ones with gradients of confinement, which can make important droplet microfluidic operations better.

This technique, paired with simple polydimethylsiloxane replica molding, can offer users with a solution for non-specialized and specialized labs in order to customize and expand microfluidic experimentation. In order to leverage the immense potential of droplet microfluidics, the process of chip design and fabrication needs to be simplified. While the PDMS replica molding has significantly transformed the chip-production process, its dependence on 2D-limited photolithography has limited the design possibilities, as well as further dissemination of microfluidics to non-specialized labs. The technique permits new possibilities in the university, meanwhile as of right now, no other methodology exists except this one that allows architectures with structures from 15 µm to hundreds of micrometers in all dimensions to be produced.

According to FEMTOprint, 3D printed glass structures characterize a negative part, and can be used as chips by bonding them to a PDMS slab or glass, which makes it possible to utilize structures, like mirrors, lenses, and filters, that replica molding cannot recreate. Chip fabrication doesn’t have to be the holdup for non-microfluidic labs adopting microfluidic approaches, instead it should be looked at as a way to device novel functionalities, like optical fiber incorporation for fluorescence detection.

 SOURCE

https://www.industrial-lasers.com/articles/2018/07/3d-printing-creates-molds-for-droplet-microfluidic-chips.html

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Stem Cells Used as Delivery Truck for Brain Cancer Drugs

Reporter: Irina Robu, PhD

Medulloblastoma, common brain cancer in children has been very difficult to treat therapeutically with traditional interventions which relies on surgical techniques to remove the bulk of the cancerous tissue. The researchers seen the need for novel treatments of medulloblastomas that have recurred, as well as for treatments that are less toxic overall. For this reason, data from University of North Carolina (UNC) Lineberger Comprehensive Cancer Center and  Eshelman School of Pharmacy published a study in PLOS named “Intra-cavity stem cell therapy inhibits tumor progression in a novel murine model of medulloblastoma surgical resection”, validates how cancer-hunting stem cells can track down and deliver a drug to terminate medulloblastoma cells hiding after surgery.

The technology in the research is an extension of a discovery that won researchers a Nobel Prize in 2012 and showed they could transform skin cells into stem cells. The research team started by reprogramming skin cells into stem cells and genetically engineered them to manufacture a substance that becomes toxic to other cells when exposed to another drug. Inserting the drug carries the stem cells into the brain of laboratory models after surgery decreased the size of tumors by 15 times and extended median survival in mice by 133%.

In this study, the scientists indicated they could shrink tumors in murine models of medulloblastoma, hence extending the rodents life. The approach holds promise for reducing side effects and helping more children with medulloblastoma. Amazingly the researchers also developed a laboratory model of medulloblastoma that allowed them to simulate the way standard care is currently delivered—surgery followed by drug therapy. Using this model, they discovered that after surgically removing a tumor, the cancer cells that remained grew faster.

According to the study investigator, Shawn Hingtgen, PhD, the cells are like a FedEx truck that will deliver cytotoxic agents directly into the tumor to a particular location. In earlier studies, Dr. Hingtgen and his colleagues showed that they could flip skin cells into stem cells that hunt and transport cancer-killing drugs to glioblastoma, the deadliest malignant brain tumor in adults.

Medulloblastoma is cancer that happens mostly in kids between ages of three and eight, and while current therapy has changed survival pretty dramatically, it can still be pretty toxic. The ability to use a patient’s own cells to target the tumor directly would be “the holy grail” of therapy, the investigators trust it could hold capacity for other rare, and sometimes fatal, brain cancer types that occur in children as well.

Source

https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0198596

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New Liver Tissue Implants Showing Potential

Reporter: Irina Robu,PhD

To develop new tissues, researchers at the Medical Research Council Center for Regenerative Medicine at the University of Edinburgh have found that stem cells transformed into 3-D liver tissue can support liver function when implanted into the mice suffering with a liver disease.

The scientists stimulated human embryonic stem cells and induced pluripotent stem cells to mature pluripotent stem cells into liver cells, hepatocytes. Hepatocytes are the chief functional cells of the liver and perform an astonishing number of metabolic, endocrine and secretory functions. Hepatocytes are exceptionally active in synthesis of protein and lipids for export. The cells are grown in 3-D conditions as small spheres for over a year. However, keeping the stem cells as liver cells for a long time is very difficult, because the viability of hepatocytes decreases in-vitro conditions.

Succeeding the discovery, the team up with materials chemists and engineers to detect appropriate polymers that have already been approved for human use that can be developed into 3-D scaffolds. The best material to use a biodegradable polyester, called polycaprolactone (PCL).PCL is degraded by hydrolysis of its ester linkages in physiological conditions (such as in the human body) and it is especially interesting for the preparation of long term implantable devices, owing to its degradation which is even slower than that of polylactide. They spun the PCL into microscopic fibers that formed a scaffold one centimeter square and a few millimeters thick.

At the same time, hepatocytes derived from embryonic cells had been grown in culture for 20 days and were then loaded onto the scaffolds and implanted under the skin of mice.Blood vessels successfully grew on the scaffolds with the mice having human liver proteins in their blood, demonstrating that the tissue had successfully integrated with the circulatory system. The scaffolds were not rejected by the animals’ immune systems.

The scientists tested the liver tissue scaffolds in mice with tyrosinaemia,a potentially fatal genetic disorder where the enzymes in the liver that break down the amino acid tyrosine are defective, resulting in the accumulation of toxic metabolic products. The implanted liver tissue aided the mice with tyrosinaemia to break down tyrosine and the mice finally lost less weight, had less buildup of toxins in the blood and exhibited fewer signs of liver damage than the control group that received empty scaffolds.

According to Rob Buckle, PhD, Chief Science Officer at the MRC, “Showing that such stem cell-derived tissue is able to reproduce aspects of liver function in the lab also offers real potential to improve the testing of new drugs where more accurate models of human tissue are needed”. It is believed that the discovery could be the next step towards harnessing stem cell reprogramming technologies to provide renewable supplies of liver tissue products for transplantation.

SOURCE

https://www.rdmag.com/article/2018/08/new-liver-tissue-implants-showing-promise?et_cid=6438323

 

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Reporter and Curator: Dr. Sudipta Saha, Ph.D.

 

Researchers have embraced CRISPR gene-editing as a method for altering genomes, but some have reported that unwanted DNA changes may slip by undetected. The tool can cause large DNA deletions and rearrangements near its target site on the genome. Such alterations can confuse the interpretation of experimental results and could complicate efforts to design therapies based on CRISPR. The finding is in line with previous results from not only CRISPR but also other gene-editing systems.

 

CRISPR -Cas9 gene editing relies on the Cas9 enzyme to cut DNA at a particular target site. The cell then attempts to reseal this break using its DNA repair mechanisms. These mechanisms do not always work perfectly, and sometimes segments of DNA will be deleted or rearranged, or unrelated bits of DNA will become incorporated into the chromosome.

 

Researchers often use CRISPR to generate small deletions in the hope of knocking out a gene’s function. But when examining CRISPR edits, researchers found large deletions (often several thousand nucleotides) and complicated rearrangements of DNA sequences in which previously distant DNA sequences were stitched together. Many researchers use a method for amplifying short snippets of DNA to test whether their edits have been made properly. But this approach might miss larger deletions and rearrangements.

 

These deletions and rearrangements occur only with gene-editing techniques that rely on DNA cutting and not with some other types of CRISPR modifications that avoid cutting DNA. Such as a modified CRISPR system to switch one nucleotide for another without cutting DNA and other systems use inactivated Cas9 fused to other enzymes to turn genes on or off, or to target RNA. Overall, these unwanted edits are a problem that deserves more attention, but this should not stop anyone from using CRISPR. Only when people use it, they need to do a more thorough analysis about the outcome.

 

References:

 

https://www.nature.com/articles/d41586-018-05736-3?utm_source=briefing-dy

 

https://www.ncbi.nlm.nih.gov/pubmed/28561021

 

https://www.ncbi.nlm.nih.gov/pubmed/30010673

 

https://www.ncbi.nlm.nih.gov/pubmed/24651067

 

https://www.ncbi.nlm.nih.gov/pubmed/25398350

 

https://www.ncbi.nlm.nih.gov/pubmed/24838573

 

https://www.ncbi.nlm.nih.gov/pubmed/25200087

 

https://www.ncbi.nlm.nih.gov/pubmed/25757625

 

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