Novel Approach to Non-Invasive Blood Glucose Monitoring Based on Transmittance and Refraction of Visible Laser Light

Current blood glucose monitoring (BGM) techniques are invasive as they require a finger prick blood sample, a repetitively painful process that creates the risk of infection. BGM is essential to avoid complications arising due to abnormal blood glucose levels in diabetic patients. Laser light-based sensors have demonstrated a superior potential for BGM. Existing near-infrared (NIR)-based BGM techniques have shortcomings, such as the absorption of light in human tissue, higher signal-to-noise ratio, and lower accuracy, and these disadvantages have prevented NIR techniques from being employed for commercial BGM applications. A simple, compact, and cost-effective non-invasive device using visible red laser light of wavelength 650 nm for BGM (RL-BGM) is implemented in this paper. The RL-BGM monitoring device has three major technical advantages over NIR. Unlike NIR, red laser light has 30 times better transmittance through human tissue. Furthermore, when compared with NIR, the refractive index of laser light is more sensitive to the variations in glucose level concentration resulting in faster response times 7-10 s. Red laser light also demonstrates both higher linearity and accuracy for BGM. The designed RL-BGM device has been tested for both in vitro and in vivo cases and several experimental results have been generated to ensure the accuracy and precision of the proposed BGM sensor. 2013 IEEE.Scopu

Recent developments in minimally and truly non-invasive blood glucose monitoring techniques

The aim of this paper is to introduce the recent research and commercial developments in minimally and non invasive blood glucose monitoring technique

Noninvasive blood glucose monitoring system based on near-infrared method

Diabetes is considered one of the life-threatening diseases in the world which need continuous monitoring to avoid the complication of diabetes. There is a need to develop a non-invasive monitoring system that avoids the risk of infection problems and pain caused by invasive monitoring techniques. This paper presents a method for developing a noninvasive technique to predict the blood glucose concentration (BCG) based on the Near-infrared (NIR) light sensor. A prototype is developed using a finger sensor based on LED of 940 nm wavelength to collect photoplethysmography (PPG) signal which is variable depending on the glucose concentration variance, a module circuit to preprocess PPG signals is realized, which includes an amplifier and analog filter circuits, an Arduino UNO is used to analog-to-digital conversion. A digital Butterworth filterer is used to remove PPG signal trends, then detect the PPG data peaks to determine the relationship between the PPG signal and (BCG) and use it as input parameters to build the calibration model based on linear regression. Experiments show that the Root Mean Squares Error (RMSE) of the prediction is between 8.264mg/dL and 13.166 mg/dL, the average of RMSE is about 10.44mg/dL with a correlation coefficient (R^2) of 0.839, it is observed that the prediction of glucose concentration is in the clinically acceptable region of the standard Clark Error Grid (CEG)

Photonic hydrogel sensors

Hydrogels are an important tools for sensing because of their sensitivity to small adjustments and reactions to physical, biological, and chemical changes. They have been used in wide range of applications such as biomedical fields for drug delivery and in diagnostics. Hydrogel-based systems are a reusable sensing platform to quantify biomarkers in high-risk patients at clinical and point-of-care settings. In this thesis, two fabrication methods have been developed to successfully detect glucose concentration, pH changes and intraocular pressure (IOP). Continuous glucose monitoring aims to achieve accurate control of blood glucose concentration to prevent hypo/hyperglycaemia in diabetic patients. Also, the development of pH changes sensing device is the key to prevent the fatal implications. The Increasing of intraocular pressure (IOP) is the main risk factor for glaucoma, which is the second major source of losing sight in the world. The first method is to developed hydrogel-based sensor by using stamping technique. A novel glucose sensor based on hydrogel with a micro-imprinted hexagonal structure was fabricated here. Our method utilized diffraction properties of a hexagonally photonic microscale concavities to detect the changes in the glucose concentration from 1 mM to 200 mM. In addition, same method was used to design a new pH hydrogel-based sensor with imprinted Fresnel lens. The sensor was able to monitor the pH changes with respond time of 5 minutes. The sensor had pH range from 4.5 to 7 and showed an increase in the sensitivity after 10 days storage in PBS solution of pH 7.4. Also, when the effect of temperature changes was investigated in the study, the temperature effect was negligible in the performance the sensor. The second method is Laser ablation of commercial contact lenses. Initially, CO2 laser (HPC LS 3040) was used to modify the surface properties of the lens at selective areas by creating 1D and 2D patterns. Laser parameters (space gap between the patterns and laser power, and scan speed) were examined to find the optimal laser setting. We managed to improve the wettability properties of the lens by increasing the density of the surface. After that, we engraved two circular micro-channels on the contact lens using CO2 laser (Rayjet laser). Three different lenses were fabricated with various spacing gap between the channels (1 mm, 1.5 mm and 2 mm). The lenses had maximum channel depth of up to 20 µm. By using laser treated lenses, a change in pressure from 12 mmHg to 22 mmHg, normal eye IOP and glaucoma patients IOP, was detect by the lenses. In summary, this thesis presents important findings that can be recommended for application in medical point-of-care diagnostics, implantable chips, and wearable continuous monitoring devices to quantify biomarkers. These methods offer sensing devices that are easy and fast to manufacture, cost effective, fast response and noninvasive sensors

A REAL TIME NON-INVASIVE HEMOGLOBIN MONITORING SYSTEM,

A REAL TIME NON-INVASIVE HEMOGLOBIN MONITORING SYSTEM

The development of novel photonics based techniques for biomedicine

The advances in technology capable of measuring various optical properties within organic materials and tissues have paved way for potentially revolutionary methods of detecting and diagnosing diseases as well as generally monitoring health. Thus, this thesis provides a background on a number of key optical properties crucial in organic tissues and describes how such properties can currently be detected and observed.The thesis looks at a diverse selection of conditions and health-monitoring challenges to determine the effectiveness of non- and minimally invasive diagnostics. Urinary bladder cancer and a computational Monte Carlo model are described in an effort to predict the effectiveness of such diagnostics tools as well as aid in the overall detection of cancer within the organ. Beginning from porcine bladder, the model is advanced to function with human biopsy samples.Furthermore, the thesis covers cardiovascular disease (CVD), specifically pre-eclampsia.Tools used for human analysis are tested on animal CVD models and ultimately employed to display their effectiveness at monitoring diseased mice from an established murine model. The thesis also presents potential parameters vital for diagnostics purposes.Using the established parameters of interest from the above work, the thesis describes measurement of physiological (photonics based diagnostics) and psychological (reaction time assessment) effects resulting from short-term light exposure. Due to the frequency at which non natural light interacts with people on a day-to-day basis, the thesis provides a basis to further expand health-monitoring research.Finally, potential methods for assessing ocular health in the form of contact lens induced discomfort is assessed through objective analysis by photonics based techniques. The thesis also establishes a validation for the proposed approach.Ultimately, the work presented in the thesis describes how novel photonics based technologies can be effectively employed in a wide variety of biomedical diagnostics and monitoring applications, whether used alone or in conjunction with other forms of diagnostics

Monte Carlo study of skin optical clearing to enhance light penetration in the tissue: implications for photodynamic therapy of acne vulgaris

ABSTRACT Result of Monte Carlo simulations of skin optical clearing is presented. The model calculations were carried out with the aim of studying of spectral response of skin under immersion liquids action and calculation of enhancement of light penetration depth. In summary, we have shown that: 1) application of glucose, propylene glycol and glycerol produced significant decrease of light scattering in different skin layers; 2) maximal clearing effect will be obtained in case of optical clearing of skin dermis, however, absorbed light fraction in skin dermis changed insignificantly, independently on clearing agent and place it administration; 3) in contrast to it, the light absorbed fraction in skin adipose layer increased significantly in case of optical clearing of skin dermis. It is very important because it can be used for development of optical methods of obesity treatment; 4) optical clearing of superficial skin layers can be used for decreasing of power of light radiation used for treatment of acne vulgaris