A Non-Invasive Semiconductor Optical System To Measure Skin Tension

The objectives of this project are to design, construct, validate and test a low-cost, non-invasive and painless device to measure skin tension. Skin is a complex, multi-layered, anisotropic material with non-linear viscoelastic behavior during stress application. The intricate balance of different semi-elastic fibers and continuous regeneration has brought difficulty to the accurate measurement of its mechanical properties. Commercial skin tension measurement products have been described, but are too expensive to be readily accessible for skin research and clinical utilization. The device to be developed in this project differs from existing devices in that it measures skin deformation under vacuum using a non-invasive, low power, reflective light sensor. The results in this report show that this “Cutisfirm” skin tension measurement system is an effective product for measuring dynamic mechanical properties of skin. The Cutisfirm device was able to measure quantified changes in skin and artificial skin models within the 95% tolerance level of ±0.139cm and up to 1.875cm/sec movement velocities. Results show changes in dorsal hand skin measured in vivo between open and closed fisted positions as a function of gender and age in a diverse population subset. The Cutisfirm skin tension measurement system could be a potential candidate for a mass-produced, affordable device option for general clinical use

Enhanced Liposuction

Liposuction began as a simple, minimally invasive method of reducing the amount of localized fat in a region. Today it is a sophisticated and complex process, with many variations in purpose and technique. In this book, a global slate of expert surgeons offers a detailed description of various minimally invasive and non-invasive options for contouring the face, neck, and body. Chapters detail the evolution and utilization of various energy-based devices and combination treatments. They also describe procedure limitations and treatment of complications. Finally, they discuss indications for various approaches with case study descriptions so readers might be assisted with treating patients in their everyday practice

Modeling an optimal 3D Skin-on-Chip within microfluidic devices for pharmacological studies

Preclinical research remains hampered by an inadequate representation of human tissue environments which results in inaccurate predictions of a drug candidate''s effects and target''s suitability. While human 2D and 3D cell cultures and organoids have been extensively improved to mimic the precise structure and function of human tissues, major challenges persist since only few of these models adequately represent the complexity of human tissues. The development of skin-on-chip technology has allowed the transition from static 3D cultures to dynamic 3D cultures resembling human physiology. The integration of vasculature, immune system, or the resident microbiome in the next generation of SoC, with continuous detection of changes in metabolism, would potentially overcome the current limitations, providing reliable and robust results and mimicking the complex human skin. This review aims to provide an overview of the biological skin constituents and mechanical requirements that should be incorporated in a human skin-on-chip, permitting pharmacological, toxicological, and cosmetic tests closer to reality

Optical pressure micro sensor for skin mechanics studies

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2006.Includes bibliographical references (leaves 78-80).The mechanics of skin is as central to touch as optics is to vision and acoustics is to hearing. With the advent of novel imaging technologies such as the Optical Coherence Tomography (OCT), we are now able to view structures within the skin to a resolution of a few microns in vivo and non-invasively. To fully understand the role of biomechanics of the skin in interpreting touch, we need to develop a quantitative understanding of how spatio temporal loads imposed on the surface of the skin are transmitted to mechanoreceptor locations within the skin. The following thesis presents a description of the design and fabrication of an Optical Pressure Sensor Device to be used in conjunction with an Optical Coherence Tomography Apparatus to quantify loads incident on the fingerpad surface. The Optical Pressure Sensor is a five layer PDMS based device having a total thickness of 150 microns. It consists of two layers of a textured pattern separated by a layer of "Soft" PDMS of thickness 100 microns. The top and bottom protective layers are of PDMS and have a thickness of 20 microns each. "Soft" PDMS is a combination of PDMS and the silicone oil "Fluid 200" and has a Young's Modulus less than that of Human Skin.(cont.) The entire device is fabricated bottom up on a silicon wafer using soft lithography techniques and the textured pattern is imprinted onto the PDMS using photolithography techniques. This flexible pressure sensor is designed to be used on the fingerpad skin to determine the pressure distribution due to incident loads. The sensor is placed between the OCT head and the finger pad to be imaged. The OCT head (along with the indenter) acts as the mechanical stimulus and is used to indent the finger pad. As a result of this stimulus, the human skin along with the pressure sensor gets deformed and both these deformations are picked up by the OCT image. The deflection between the two bands of patterns is used to estimate the stress at the pressure sensor and skin interface through the development of a continuum mechanics model which is also developed and introduced in this thesis. The manufactured device is tested and calibrated for use with the fingerpad.by Siddarth Kumar.S.M

Design, characterization and validation of integrated bioelectronics for cellular studies: from inkjet-printed sensors to organic actuators

Mención Internacional en el título de doctorAdvances in bioinspired and biomimetic electronics have enabled coupling engineering devices to biological systems with unprecedented integration levels. Major efforts, however, have been devoted to interface malleable electronic devices externally to the organs and tissues. A promising alternative is embedding electronics into living tissues/organs or, turning the concept inside out, lading electronic devices with soft living matters which may accomplish remote monitoring and control of tissue’s functions from within. This endeavor may unleash the ability to engineer “living electronics” for regenerative medicine and biomedical applications. In this context, it remains a challenge to insert electronic devices efficiently with living cells in a way that there are minimal adverse reactions in the biological host while the electronics maintaining the engineered functionalities. In addition, investigating in real-time and with minimal invasion the long-term responses of biological systems that are brought in contact with such bioelectronic devices is desirable. In this work we introduce the development (design, fabrication and characterization) and validation of sensors and actuators mechanically soft and compliant to cells able to properly operate embedded into a cell culture environment, specifically of a cell line of human epithelial keratinocytes. For the development of the sensors we propose moving from conventional microtechnology approaches to techniques compatible with bioprinting in a way to support the eventual fabrication of tissues and electronic sensors in a single hybrid plataform simultaneously. For the actuators we explore the use of electroactive, organic, printing-compatible polymers to induce cellular responses as a drug-free alternative to the classic chemical route in a way to gain eventual control of biological behaviors electronically. In particular, the presented work introduces inkjet-printed interdigitated electrodes to monitor label-freely and non-invasively cellular migration, proliferation and cell-sensor adhesions of epidermal cells (HaCaT cells) using impedance spectroscopy and the effects of (dynamic) mechanical stimulation on proliferation, migration and morphology of keratinocytes by varying the magnitude, frequency and duration of mechanical stimuli exploiting the developed biocompatible actuator. The results of this thesis contribute to the envision of three-dimensional laboratory-growth tissues with built-in electronics, paving exciting avenues towards the idea of living smart cyborg-skin substitutes.En los útimos años los avances en el desarrollo de dispositivos electrónicos diseñados imitando las propiedades de sistemas vivos han logrado acoplar sistemas electrónicos y órganos/tejidos biológicos con un nivel de integración sin precedentes. Convencionalmente, la forma en que estos sistemas bioelectrónicos son integrados con órganos o tejidos ha sido a través del contacto superficial entre ambos sistemas, es decir acoplando la electrónica externamente al tejido. Lamentablemente estas aproximaciones no contemplan escenarios donde ha habido una pérdida o daño del tejido con el cual interactuar, como es el caso de daños en la piel debido a quemaduras, úlceras u otras lesiones genéticas o producidas. Una alternativa prometedora para ingeniería de tejidos y medicina regenerativa, y en particular para implantes de piel, es embeber la electrónica dentro del tejido, o presentado de otra manera, cargar el sistema electrónico con células vivas y tejidos fabricados por ingeniería de tejidos como parte innata del propio dispositivo. Este concepto permitiría no solo una monitorización remota y un control basado en señalizaciones eléctricas (sin químicos) de tejidos biológicos fabricados mediante técnicas de bioingeniería desde dentro del propio tejido, sino también la fabricación de una “electrónica viva”, biológica y eléctricamente funcional. En este contexto, es un desafío insertar de manera eficiente dispositivos electrónicos con células vivas sin desencadenar reacciones adversas en el sistema biológico receptor ni en el sistema electrónico diseñado. Además, es deseable monitorizar en tiempo real y de manera mínimamente invasiva las respuestas de dichos sistemas biológicos que se han añadido a tales dispositivos bioelectrónicos. En este trabajo presentamos el desarrollo (diseño, fabricación y caracterización) y validación de sensores y actuadores mecánicamente suaves y compatibles con células capaces de funcionar correctamente dentro de un entorno de cultivo celular, específicamente de una línea celular de células epiteliales humanas. Para el desarrollo de los sensores hemos propuesto utilizar técnicas compatibles con la bioimpresión, alejándonos de la micro fabricación tradicionalmente usada para la manufactura de sensores electrónicos, con el objetivo a largo plazo de promover la fabricación de los tejidos y los sensores electrónicos simultáneamente en un mismo sistema de impresión híbrido. Para el desarrollo de los actuadores hemos explorado el uso de polímeros electroactivos y compatibles con impresión y hemos investigado el efecto de estímulos mecánicos dinámicos en respuestas celulares con el objetivo a largo plazo de autoinducir comportamientos biológicos controlados de forma electrónica. En concreto, este trabajo presenta sensores basados en electrodos interdigitados impresos por inyección de tinta para monitorear la migración celular, proliferación y adhesiones célula-sustrato de una línea celular de células epiteliales humanas (HaCaT) en tiempo real y de manera no invasiva mediante espectroscopía de impedancia. Por otro lado, este trabajo presenta actuadores biocompatibles basados en el polímero piezoeléctrico fluoruro de poli vinilideno y ha investigado los efectos de estimular mecánicamente células epiteliales en relación con la proliferación, migración y morfología celular mediante variaciones dinámicas de la magnitud, frecuencia y duración de estímulos mecánicos explotando el actuador biocompatible propuesto. Ambos sistemas presentados como resultado de esta tesis doctoral contribuyen al desarrollo de tejidos 3D con electrónica incorporada, promoviendo una investigación hacia la fabricación de sustitutos equivalentes de piel mitad orgánica mitad electrónica como tejidos funcionales biónicos inteligentes.The main works presented in this thesis have been conducted in the facilities of the Universidad Carlos III de Madrid with support from the program Formación del Profesorado Universitario FPU015/06208 granted by Spanish Ministry of Education, Culture and Sports. Some of the work has been also developed in the facilities of the Fraunhofer-Institut für Zuverlässigkeit und Mikrointegration (IZM) and University of Applied Sciences (HTW) in Berlin, under the supervision of Prof. Dr. Ing. H-D. Ngo during a research visit funded by the Mobility Fellows Program by the Spanish Ministry of Education, Culture, and Sports. This work has been developed in the framework of the projects BIOPIELTEC-CM (P2018/BAA-4480), funded by Comunidad de Madrid, and PARAQUA (TEC2017-86271-R) funded by Ministerio de Ciencia e Innovación.Programa de Doctorado en Ingeniería Eléctrica, Electrónica y Automática por la Universidad Carlos III de MadridPresidente: José Antonio García Souto.- Secretario: Carlos Elvira Pujalte.- Vocal: María Dimak

Textbook on Scar Management

This text book is open access under a CC BY 4.0 license. Written by a group of international experts in the field and the result of over ten years of collaboration, it allows students and readers to gain to gain a detailed understanding of scar and wound treatment – a topic still dispersed among various disciplines. The content is divided into three parts for easy reference. The first part focuses on the fundamentals of scar management, including assessment and evaluation procedures, classification, tools for accurate measurement of all scar-related elements (volume density, color, vascularization), descriptions of the different evaluation scales. It also features chapters on the best practices in electronic-file storage for clinical reevaluation and telemedicine procedures for safe remote evaluation. The second section offers a comprehensive review of treatment and evidence-based technologies, presenting a consensus of the various available guidelines (silicone, surgery, chemical injections, mechanical tools for scar stabilization, lasers). The third part evaluates the full range of emerging technologies offered to physicians as alternative or complementary solutions for wound healing (mechanical, chemical, anti-proliferation). Textbook on Scar Management will appeal to trainees, fellows, residents and physicians dealing with scar management in plastic surgery, dermatology, surgery and oncology, as well as to nurses and general practitioners ; Comprehensive reference covering the complete field of wounds and scar management: semiology, classifications and scoring Highly educational contents for trainees as well as professionals in plastic surgery, dermatology, surgery, oncology as well as nurses and general practitioners Fast access to information through key points, take home messages, highlights, and a wealth of clinical cases Book didactic contents enhanced by supplementary material and video

On the development of a cybernetic prosthetic hand

The human hand is the end organ of the upper limb, which in humans serves the important function of prehension, as well as being an important organ for sensation and communication. It is a marvellous example of how a complex mechanism can be implemented, capable of realizing very complex and useful tasks using a very effective combination of mechanisms, sensing, actuation and control functions. In this thesis, the road towards the realization of a cybernetic hand has been presented. After a detailed analysis of the model, the human hand, a deep review of the state of the art of artificial hands has been carried out. In particular, the performance of prosthetic hands used in clinical practice has been compared with the research prototypes, both for prosthetic and for robotic applications. By following a biomechatronic approach, i.e. by comparing the characteristics of these hands with the natural model, the human hand, the limitations of current artificial devices will be put in evidence, thus outlining the design goals for a new cybernetic device. Three hand prototypes with a high number of degrees of freedom have been realized and tested: the first one uses microactuators embedded inside the structure of the fingers, and the second and third prototypes exploit the concept of microactuation in order to increase the dexterity of the hand while maintaining the simplicity for the control. In particular, a framework for the definition and realization of the closed-loop electromyographic control of these devices has been presented and implemented. The results were quite promising, putting in evidence that, in the future, there could be two different approaches for the realization of artificial devices. On one side there could be the EMG-controlled hands, with compliant fingers but only one active degree of freedom. On the other side, more performing artificial hands could be directly interfaced with the peripheral nervous system, thus establishing a bi-directional communication with the human brain

Textbook on Scar Management

This text book is open access under a CC BY 4.0 license. Written by a group of international experts in the field and the result of over ten years of collaboration, it allows students and readers to gain to gain a detailed understanding of scar and wound treatment – a topic still dispersed among various disciplines. The content is divided into three parts for easy reference. The first part focuses on the fundamentals of scar management, including assessment and evaluation procedures, classification, tools for accurate measurement of all scar-related elements (volume density, color, vascularization), descriptions of the different evaluation scales. It also features chapters on the best practices in electronic-file storage for clinical reevaluation and telemedicine procedures for safe remote evaluation. The second section offers a comprehensive review of treatment and evidence-based technologies, presenting a consensus of the various available guidelines (silicone, surgery, chemical injections, mechanical tools for scar stabilization, lasers). The third part evaluates the full range of emerging technologies offered to physicians as alternative or complementary solutions for wound healing (mechanical, chemical, anti-proliferation). Textbook on Scar Management will appeal to trainees, fellows, residents and physicians dealing with scar management in plastic surgery, dermatology, surgery and oncology, as well as to nurses and general practitioners ; Comprehensive reference covering the complete field of wounds and scar management: semiology, classifications and scoring Highly educational contents for trainees as well as professionals in plastic surgery, dermatology, surgery, oncology as well as nurses and general practitioners Fast access to information through key points, take home messages, highlights, and a wealth of clinical cases Book didactic contents enhanced by supplementary material and video

Laser-induced thermoelastic effects can evoke tactile sensations

Humans process a plethora of sensory information that is provided by various entities in the surrounding environment. Among the five major senses, technology for touch, haptics, is relatively young and has relatively limited applications largely due to its need for physical contact. In this article, we suggest a new way for non-contact haptic stimulation that uses laser, which has potential advantages such as mid-air stimulation, high spatial precision, and long working distance. We demonstrate such tactile stimulation can be enabled by laser-induced thermoelastic effects by means of physical and perceptual studies, as well as simulations. In the physical study, the mechanical effect of laser on a human skin sample is detected using low-power radiation in accordance with safety guidelines. Limited increases (< similar to 2.5 degrees C) in temperature at the surface of the skin, examined by both thermal camera and the Monte Carlo simulation, indicate that laser does not evoke heat-induced nociceptive sensation. In the human EEG study, brain responses to both mechanical and laser stimulation are consistent, along with subjective reports of the non-nociceptive sensation of laser stimuli.close1