Pharmaceutical: How to measure the compressibility of intraocular devices
For AIDS patients, retinitis (contracted from the cytomegalovirus) is among the most common opportunistic infections, which if left untreated inevitably results in blindness. To replace intravitreal therapy, which is highly invasive, among the most promising developments are intraocular implants/devices designed to deliver drugs with precision directly to the required areas offering several advantages to alternative therapies. However, such devices are extremely complicated to manufacture, are prohibitively expensive and (as they are not biodegradable) at the point of removal may increase the risk of wound leaking.
As a result, researchers developed a small implantable doughnut-shaped minitablet that erodes in the body. Their TA.XTplus Texture Analyser was used to characterise the compressibility of the polymers used in making the device using a ball probe indentation of the tablet to obtain its Brinell hardness number. The low compression forces of the polymer material chosen deemed it suitable for the device with regard to wear on major tableting equipment such as punches and dies.
Pharmaceutical: How to measure the mechanical properties of temporary scaffolds
Tissue engineering is a promising technology for treating tissue defects or replacing nonfunctional tissues/organs. It relies upon a temporary scaffold that is basically an artificial structure which provides the support for 3D tissue formation or organogenesis.
Ideally, scaffolds should be able to accommodate human cells, orchestrate their growth and differentiation leading to tissue regeneration and ultimately make it feasible for implantation. Since ligament injury is most common and ligament-alone grafts are not so successful to replace the injured ligaments, the researchers are experimenting with the construction of a composite scaffold which can guide the stem cells to differentiate into fibrocartilage that bridges the bone-ligament interface, i.e. enthesis.
Scientists at the Indian National Institute of Technology in Rourkela used their Texture Analyser for the publication ‘Fabrication of silk-based composite scaffold for bone-ligament-bone graft using aqueous polymeric dispersion technique’. Tensile tests were carried out on temporary scaffolds that provide support for 3D tissue formation. Silk-based multi-compartmental scaffolds were found to be suitable for enthesis tissue engineering due to their porosity and matching mechanical properties.
Medical: How to measure tablet dispersion
Aprecia Pharmaceuticals announced some exciting news in March 2016 for people who take Levetiracetem, a medication that helps prevent seizures. Levetiracetem comes in a large pill format that can be difficult for many adults and children to swallow. Doctors have long been aware of what happens if the experience of taking the medication is unpleasant. It’s common in these cases that patients will often skip, forgot, or avoid taking their medication.
Aprecia has developed a method called ZipDose that uses to 3D printing to manufacture Levetiracetem. The 3D printed tablets deliver a highly efficient dose and dissolve instantly with a sip of water. The drug’s new form is expected to greatly improve the experience of patients who take the medicine.
The TA.XTplus Texture Analyser was used to test and analyse the tablet’s dispersion time in aqueous fluid.
Medical: How to measure the mechanical strength of nanocomposite sponges
The field of orthopedic tissue engineering is quickly expanding with the development of novel materials and strategies designed for rapid bone regeneration. While autologous bone grafts continue to be the standard of care, drawbacks include donor-site morbidity and short tissue supplies.
Researchers at North Western University developed a novel nanocomposite sponge composed of poly(1,8-octanediol-co-citrate) (POC) and the bioactive ceramic β-tricalcium phosphate (TCP). used their TA.XTplus Texture Analyser to publish ‘Advanced Nanocomposites for bone regeneration’. The Texture Analyser was used to assess the mechanical strength of a novel nanocomposite sponge using repeat compression tests.
The researchers showed that these nanocomposite sponges could be used as a depot for bone-producing (osteogenic) growth factors and supported the use of this sponge for future bone tissue engineering efforts.
Medical: How to measure the tensile strength of cartilage grafts
Bioprinting is an emerging technology for the fabrication of patient-specific, anatomically complex tissues and organs. A novel bioink for printing cartilage grafts was developed based on two unmodified FDA-compliant polysaccharides, gellan and alginate, combined with the clinical product BioCartilage (cartilage extracellular matrix particles).
Researchers at ETH Zürich published a paper of their work entitled 'Bioprinting Complex Cartilaginous Structures with Clinically Compliant Biomaterials' that employed their TA.XTplus Texture Analyser to perform tensile tests on dumbbell shaped samples of bioprinted cartilage grafts, finding them to be strong and ductile. This enabled the development of patient-specific cartilage grafts with good mechanical and biological properties.
The versatile method can be used with any type of tissue particles to create tissue-specific and bioactive scaffolds.
Medical Devices: How to measure the biomechanics of sternum closures
Poor healing of median sternotomy can significantly increase morbidity, mortality, and hospital costs. Effective union requires reliable sternal fixation. Although wire has proven the most reliable and widely used sternotomy closure material, no experimental studies had compared a large variety of wiring techniques in a human model.
At the University of Missouri-Columbia, researchers developed an easily reproducible experimental model using cadaveric human sterna and compared several wiring methods to assess closure strength and stability. They employed their Texture Analyser to carry out a study on the biomechanics of sternum closures after a sternotomy.
Fifty-three fresh adult human cadaveric sternal plates with adjacent ribs were fixed with specially designed spiked stainless steel clamps and attached to a TA.HD Texture Analyser. The texture analyser was used to assess stiffness and displacement using perpendicular repetitive variable force loads of 800 Newtons cycling at a rate of 0.5mm/s. A range of closures were assessed.
This new way of sternotomy closure testing was found to be reliable, inexpensive, and easily reproducible and distinguished the suitable closures from the unsuitable.
Medical Devices: How to measure the cyclical compressive strength of intravaginal rings
Researchers, and experts at physical characterisation at Queen’s University Belfast, have been using their TA.XTplus extensively for many years in both pharmaceutical and medical device applications. More recently they used their Texture Analyser to study the cyclical compressive strength of a range of formulations for intravaginal rings for HIV microbicide delivery.
The mechanical properties of an IVR must ensure optimal vaginal compatibility and user acceptability. If the mechanical strength is too low, the ring could either be expulsed from the vagina or be prone to rupture. If the mechanical strength is too high, the inflexibility of the device could cause irritation or ulceration of the vaginal tissue.
Additionally, the mechanical characteristics of the rings before and after release were tested to look at the influence of the presence of active drugs on their mechanical characteristics.