Fluorescence Molecular Targeting of Colon Cancer to Visualize the Invisible

Colorectal cancer (CRC) is a common cause of cancer and cancer-related death. Surgery is the only curative modality. Fluorescence-enhanced visualization of CRC with targeted fluorescent probes that can delineate boundaries and target tumor-specific biomarkers can increase rates of curative resection. Approaches to enhancing visualization of the tumor-to-normal tissue interface are active areas of investigation. Nonspecific dyes are the most-used approach, but tumor-specific targeting agents are progressing in clinical trials. The present narrative review describes the principles of fluorescence targeting of CRC for diagnosis and fluorescence-guided surgery with molecular biomarkers for preclinical or clinical evaluation.

Ten Years of Pediatric Lung Ultrasound: A Narrative Review

Lung diseases are the most common conditions in newborns, infants, and children and are also the primary cause of death in children younger than 5 years old. Traditionally, the lung was not thought to be a target for an ultrasound due to its inability to penetrate the gas-filled anatomical structures. With the deepening of knowledge on ultrasound in recent years, it is now known that the affected lung produces ultrasound artifacts resulting from the abnormal tissue/gas/tissue interface when ultrasound sound waves penetrate lung tissue. Over the years, the application of lung ultrasound (LUS) has changed and its main indications in the pediatric population have expanded. This review analyzed the studies on lung ultrasound in pediatrics, published from 2010 to 2020, with the aim of highlighting the usefulness of LUS in pediatrics. It also described the normal and abnormal appearances of the pediatric lung on ultrasound as well as the benefits, limitations, and possible future challenges of this modality.

Finite Element Modeling of Magnitude and Location of Brain Micromotion Induced Strain for Intracortical Implants

Micromotion-induced stress remains one of the main determinants of life of intracortical implants. This is due to high stress leading to tissue injury, which in turn leads to an immune response coupled with a significant reduction in the nearby neural population and subsequent isolation of the implant. In this work, we develop a finite element model of the intracortical probe-tissue interface to study the effect of implant micromotion, implant thickness, and material properties on the strain levels induced in brain tissue. Our results showed that for stiff implants, the strain magnitude is dependent on the magnitude of the motion, where a micromotion increase from 1 to 10 μm induced an increase in the strain by an order of magnitude. For higher displacement over 10 μm, the change in the strain was relatively smaller. We also showed that displacement magnitude has no impact on the location of maximum strain and addressed the conflicting results in the literature. Further, we explored the effect of different probe materials [i.e., silicon, polyimide (PI), and polyvinyl acetate nanocomposite (PVAc-NC)] on the magnitude, location, and distribution of strain. Finally, we showed that strain distribution across cortical implants was in line with published results on the size of the typical glial response to the neural probe, further reaffirming that strain can be a precursor to the glial response.

An unsteady analysis of two-phase binding of drug in an asymmetric stenosed vessel

In this paper, we investigate endovascular delivery to get a step ahead of the pharmacological limitations it has due to the complexity of dealing with a patient-specific vessel through a mathematical model. We divide the domain of computation into four sub-domains: the lumen, the lumen-tissue interface, the upper tissue and the lower tissue which are extracted from an asymmetric atherosclerotic image derived by the intravascular ultrasound (IVUS) technique. The injected drug at the luminal inlet is transported with the streaming blood which is considered Newtonian. An irreversible uptake kinetics of the injected drug at the lumen-tissue interface from the luminal side to the tissue domains is assumed. Subsequently, the drug is dispersed within the tissue followed by its retention in the extracellular matrix (ECM) and by receptor-mediated binding. The Marker and Cell (MAC) method has been leveraged to get a quantitative insight into the model considered. The effect of the wall absorption parameter on the concentration of all drug forms (free as well as two-phase bound) has been thoroughly investigated, and some other important factors, such as the averaged concentration, the tissue content, the fractional effect, the concentration variance and the effectiveness of drug have been graphically analyzed to gain a clear understanding of endovascular delivery. The simulated results predict that with increasing values of the absorption parameter, the averaged concentrations of all drug forms do decrease. An early saturation of binding sites takes place for smaller values of the absorption parameter, and also rapid saturation of ECM binding sites occurs as compared to receptor binding sites. Results also predict the influence of surface roughness as well as asymmetry of the domain about the centerline on the distribution and retention of drug. A thorough sensitivity analysis has been carried out to determine the influence of some parameters involved.

Developing Mg-Zn-Fish Bone Derived Hydroxyapatite Composites for Biomedical Applications: In vitro Degradation Studies

The study of magnesium (Mg) based biomaterials has emerged as a potential research area in recent times. Controlling the rapid corrosion and improving the implant-tissue interface kinetics for better tissue regeneration are the prime interests behind developing novel Mg-based composites. In the current work, the metal matrix composites of Mg-Zn, dispersed with nano-hydroxyapatite derived from fish bones (fHA), were produced by powder metallurgy route. The powders were mixed with the help of ball milling in the presence of ethanol and then sintered at 440 °C. From the microstructural studies, micro-lamellar morphology was noticed for the sintered compacts due to the flake-like morphology of the milled powders. The sintered compacts were then subjected to in vitro biodegradation studies in simulated conditions for one week. From the results, the presence of fHA was found to be highly influential in increasing the rate of mineral deposition on the surface of the composites. These higher mineral depositions protected the surface of the composites from further degradation. The results demonstrate that adding fHA to Mg accelerates biomineralization and controls degradation, leading to better implant-tissue interactions.

Three-dimensional in vitro model of the device-tissue interface reveals innate neuroinflammation can be mitigated by antioxidant ceria nanoparticles

The recording instability of neural implants due to neuroinflammation at the device-tissue interface (DTI) is a primary roadblock to broad adoption of brain-machine interfaces. While a multiphasic immune response, marked by glial scaring, oxidative stress (OS), and neurodegeneration, is well-characterized, the independent contributions of systemic and local innate immune responses are not well-understood. Three-dimensional primary neural cultures provide a unique environment for studying the drivers of neuroinflammation by decoupling the innate and systemic immune systems, while conserving an endogenous extracellular matrix and structural and functional network complexity. We created a three-dimensional in vitro model of the DTI by seeding primary cortical cells around microwires. Live imaging of microtissues over time revealed independent innate neuroinflammation, marked by increased OS, decreased neuronal density, and increased functional connectivity. We demonstrated the use of this model for therapeutic screening by directly applying drugs to neural tissue, bypassing low bioavailability through the in vivo blood brain barrier. As there is growing interest in long-acting antioxidant therapies, we tested efficacy of perpetual antioxidant ceria nanoparticles, which reduced OS, increased neuronal density, and protected functional connectivity. Overall, our avascular in vitro model of the DTI exhibited symptoms of OS-mediated innate neuroinflammation which were mitigated by antioxidant intervention.

Biomechanical Influences on Mesh-Related Complications in Incisional Hernia Repair

Aim: Hernia repair strengthens the abdominal wall with a textile mesh. Recurrence and pain indicate weak bonds between mesh and tissue. It remains a question which biomechanical factors strengthen the mesh-tissue interface, and whether surgeons can enhance the bond between mesh and tissue.Material and Methods: This study assessed the strength of the mesh-tissue interface by dynamic loads. A self-built bench test delivered dynamic impacts. The test simulated coughing. Porcine and bovine tissue were used for the bench test. Tissue quality, mesh adhesiveness, and fixation intensity influenced the retention power. The influences were condensed in a formula to assess the durability of the repair. The formula was applied to clinical work. The relative strength of reconstruction was related to the individual human abdominal wall. From computerized tomography at rest and during Valsalva's Maneuver, the tissue quality of the individual patient was determined before surgery.Results: The results showed that biomechanical parameters observed in porcine, bovine, and human tissue were in the same range. Tissues failed in distinct patterns. Sutures slackened or burst at vulnerable points. Both the load duration and the peak load increased destruction. Stress concentrations elevated failure rates. Regional areas of force contortions increased stress concentrations. Hernia repair improved strain levels. Measures for improvement included the closure of the defect, use of higher dynamic intermittent strain (DIS) class meshes, increased mesh overlap, and additional fixation. Surgeons chose the safety margin of the reconstruction as desired.Conclusion: The tissue quality has now been introduced into the concept of a critical and a gained resistance toward pressure-related impacts. A durable hernia repair could be designed from available coefficients. Using biomechanical principles, surgeons could minimize pain levels. Mesh-related complications such as hernia recurrence can potentially be avoided in incisional hernia repair.

Peri-implant soft tissue au gmentation with connective tissue graft using „Two stage“ technique

Soft tissue augmentation using autogenous gingival grafts is a procedure often used in implantology and periodontal surgery. The technique of connective tissue grafting refers to the placement of connective tissue under a flap of partial thickness, which aims to induce the formation of keratinized tissue. It is indicated for partially or totally edentulous patients to increase the areas with the absence or reduction of the height of the keratinized tissue, as well as to increase the volume of soft tissue. The structural differences between the implant / bone tissue interface and the natural tooth / bone tissue make dental implants more susceptible to the development of inflammatory processes and bone loss. For these reasons, the intangibility of the seal around the implants is one of the primary objectives in its success over a long period of time. The function of the peri–implant seal is to “maintain internal homeostasis in response to external environmental challenges.”

Electrophoretic Deposition of Biocompatible and Bioactive Hydroxyapatite-Based Coatings on Titanium

Current trends in biomaterials science address the issue of integrating artificial materials as orthopedic or dental implants with biological materials, e.g., patients’ bone tissue. Problems arise due to the simple fact that any surface that promotes biointegration and facilitates osteointegration may also provide a good platform for the rapid growth of bacterial colonies. Infected implant surfaces easily lead to biofilm formation that poses a major healthcare concern since it could have destructive effects and ultimately endanger the patients’ life. As of late, research has centered on designing coatings that would eliminate possible infection but neglected to aid bone mineralization. Other strategies yielded surfaces that could promote osseointegration but failed to prevent microbial susceptibility. Needless to say, in order to assure prolonged implant functionality, both coating functions are indispensable and should be addressed simultaneously. This review summarizes progress in designing multifunctional implant coatings that serve as carriers of antibacterial agents with the primary intention of inhibiting bacterial growth on the implant-tissue interface, while still promoting osseointegration.