Evaluation of Olive Oil Quality with Electrochemical Sensors and Biosensors: A Review

Electrochemical sensors, sensor arrays and biosensors, alongside chemometric instruments, have progressed remarkably of late, being used on a wide scale in the qualitative and quantitative evaluation of olive oil. Olive oil is a natural product of significant importance, since it is a rich source of bioactive compounds with nutritional and therapeutic properties, and its quality is important both for consumers and for distributors. This review aims at analysing the progress reported in the literature regarding the use of devices based on electrochemical (bio)sensors to evaluate the bioactive compounds in olive oil. The main advantages and limitations of these approaches on construction technique, analysed compounds, calculus models, as well as results obtained, are discussed in view of estimation of future progress related to achieving a portable, practical and rapid miniature device for analysing the quality of virgin olive oil (VOO) at different stages in the manufacturing process.

Three-Dimensional Modeling and 3D Printing of Biocompatible Orthodontic Power-Arm Design with Clinical Application

Three-dimensional (3D) printing with biocompatible resins offers new competition to its opposition—subtractive manufacturing, which currently dominates in dentistry. Removing dental material layer-by-layer with lathes, mills or grinders faces its limits when it comes to the fabrication of detailed complex structures. The aim of this original research was to design, materialize and clinically evaluate a functional and resilient shape of the orthodontic power-arm by means of biocompatible 3D printing. To improve power-arm resiliency, we have employed finite element modelling and analyzed stress distribution to improve the original design of the power-arm. After 3D printing, we have also evaluated both designs clinically. This multidisciplinary approach is described in this paper as a feasible workflow that might inspire application other individualized biomechanical appliances in orthodontics. The design is a biocompatible power-arm, a miniature device bonded to a tooth surface, translating significant bio-mechanical force vectors to move a tooth in the bone. Its design must be also resilient and fully individualized to patient oral anatomy. Clinical evaluation of the debonding rate in 50 randomized clinical applications for each power-arm-variant showed significantly less debonding incidents in the improved power-arm design (two failures = 4%) than in the original variant (nine failures = 18%).

Capillary Transport of Miniature Soft Ribbons

Manipulation of soft miniature devices is important in the construction of soft robots, wearable devices, and biomedical devices. However, transport of soft miniature devices is still a challenging task, and few studies has been conducted on the subject. This paper reports a droplet-based micromanipulation method for transporting miniature soft ribbons. We show that soft ribbons can be successfully picked up and released to the target location using water droplets. We analyze the forces involved during the process numerically and investigate the influence of the width of the ribbon on the deformation. We verify that the deformation of a soft ribbon caused by elasto-capillary phenomena can be calculated using a well-known equation for calculating the deflection of a cantilever beam. The experimental and theoretical results show that the deformability of a soft miniature device during manipulation depends on its width.

Theoretical evaluation of a fiber-optic SPR biosensor based on a gold layer treated with thiol acid

In the present work, we have investigated the surface plasmons resonance (SPR) biosensor based on optical fiber applied for the detection of pathogenic bacteria (Escherichia coli), in order to overcome the stresses caused by the massive prism and to obtain a reliable and efficient miniature device. The modeling procedure is based on a matrix formalism developed for the optical studies of multilayer media. We have tested the response of the fiber optic biosensor based on a golden substrate functionalized with thiol acid. The results show that the SPR biosensor sensitivity is improved by treating the gold electrode with thiol. An improved SPR biosensor with a high resolution is obtained.

Cellular microfluidic technologies for biomodeling of pathological processes

Стремительный технический прогресс способствует появлению все новых подходов в клеточной биологии, одним из них является клеточная микрофлюидика. Применение технологий микрофлюидики открыло новые возможности по культивированию, прецизионному анализу и манипулированию как популяциями клеток, так и отдельными клетками. Основой новой технологии является микрофлюидный чип - миниатюрное устройство, содержащее систему микро- и наноканалов, полостей, мембран и других элементов. Возможность прецизионного управления пространственным расположением клеток и их микроокружением предоставляет уникальные и беспрецедентные возможности для биомоделирования in vitro фунциональных элементов органов и тканей. В данном обзоре приведены примеры построения и применения таких трехмерных микрофлюидных клеточных моделей для анализа протекающих в них физиологических и патологических процессов. Особое внимание уделено влиянию клеточного микроокружения клетки на её функционирование. Significant technological progress has brought new approaches to cell biology. Using microfluidic technologies has opened new opportunities for cultivation, analysis, and manipulation of both individual cells and their populations. The basis of the new technology is a microfluidic chip, a miniature device containing a system of micro- and nanochannels, cavities, membranes, and other elements. The precise control of spatial arrangement of cells and their microenvironment opens new prospects for in vitro biomodeling of functional elements of organs and tissues. This review shows examples for construction and application of such three-dimensional microfluidic cellular models for analysis of physiological and pathological processes. Particular attention is paid to the influence of cellular microenvironment on cell functioning.