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Tripathy HP, Pattanaik P, Mishra DK, Kamilla SK, Holderbaum W. Experimental and probabilistic model validation of ultrasonic MEMS transceiver for blood glucose sensing. Sci Rep 2022; 12:21259. [PMID: 36481774 PMCID: PMC9732296 DOI: 10.1038/s41598-022-25717-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Accepted: 12/05/2022] [Indexed: 12/13/2022] Open
Abstract
In contrast to traditional laboratory glucose monitoring, recent developments have focused on blood glucose self-monitoring and providing patients with a self-monitoring device. This paper proposes a system based on ultrasound principles for quantifying glucose levels in blood by conducting an in-vitro experiment with goat blood before human blood. The ultrasonic transceiver is powered by a frequency generator that operates at 40 kHz and 1.6 V, and variations in glucose level affect the ultrasonic transceiver readings. The RVM probabilistic model is used to determine the variation in glucose levels in a blood sample. Blood glucose levels are measured simultaneously using a commercial glucose metre for confirmation. The experimental data values proposed are highly correlated with commercial glucose metre readings. The proposed ultrasonic MEMS-based blood glucometer measures a glucose level of [Formula: see text] mg/dl. In the near future, the miniature version of the experimental model may be useful to human society.
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Affiliation(s)
- Hara Prasada Tripathy
- grid.412612.20000 0004 1760 9349Semiconductor Research Laboratory, Faculty of Engineering and Technology (ITER), Siksha ‘O’ Anusandhan (Deemed to be University), Bhubaneswar, 751030 India
| | - Priyabrata Pattanaik
- grid.412612.20000 0004 1760 9349Semiconductor Research Laboratory, Faculty of Engineering and Technology (ITER), Siksha ‘O’ Anusandhan (Deemed to be University), Bhubaneswar, 751030 India
| | - Dilip Kumar Mishra
- grid.412612.20000 0004 1760 9349Semiconductor Research Laboratory, Faculty of Engineering and Technology (ITER), Siksha ‘O’ Anusandhan (Deemed to be University), Bhubaneswar, 751030 India
| | - Sushanta Kumar Kamilla
- grid.412612.20000 0004 1760 9349Semiconductor Research Laboratory, Faculty of Engineering and Technology (ITER), Siksha ‘O’ Anusandhan (Deemed to be University), Bhubaneswar, 751030 India
| | - William Holderbaum
- grid.9435.b0000 0004 0457 9566School of Biological Science, Biomedical Engineering, University of Reading, Whiteknights, RG6 6AY UK
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Guan Y, Liu L, Yu S, Lv F, Guo M, Luo Q, Zhang S, Wang Z, Wu L, Lin Y, Liu G. A Noninvasive Sweat Glucose Biosensor Based on Glucose Oxidase/Multiwalled Carbon Nanotubes/Ferrocene-Polyaniline Film/Cu Electrodes. MICROMACHINES 2022; 13:mi13122142. [PMID: 36557441 PMCID: PMC9787487 DOI: 10.3390/mi13122142] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Revised: 10/11/2022] [Accepted: 12/01/2022] [Indexed: 06/01/2023]
Abstract
Diabetes remains a great threat to human beings' health and its world prevalence is projected to reach 9.9% by 2045. At present, the detection methods used are often invasive, cumbersome and time-consuming, thus increasing the burden on patients. In this paper, we propose a novel noninvasive and low-cost biosensor capable of detecting glucose in human sweat using enzyme-based electrodes for point-of-care uses. Specifically, an electrochemical method is applied for detection and the electrodes are covered with multilayered films including ferrocene-polyaniline (F-P), multi-walled carbon nanotubes (MWCNTs) and glucose oxidase (GOx) on Cu substrates (GOx/MWCNTs/F-P/Cu). The coated layers enhance the immobilization of GOx, increase the conductivity of the anode and improve the electrochemical properties of the electrode. Compared with the Cu electrode and the F-P/Cu electrode, a maximum peak current is obtained when the MWCNTs/F-P/Cu electrode is applied. We also study its current response by cyclic voltammetry (CV) at different concentrations (0-2.0 mM) of glucose solution. The best current response is obtained at 0.25 V using chronoamperometry. The effective working lifetime of an electrode is up to 8 days. Finally, to demonstrate the capability of the electrode, a portable, miniaturized and integrated detection device based on the GOx/MWCNTs/F-P/Cu electrode is developed. The results exhibit a short response time of 5 s and a correlation coefficient R2 of 0.9847 between the response current of sweat with blood glucose concentration. The LOD is of 0.081 mM and the reproducibility achieved in terms of RSD is 3.55%. The sweat glucose sensor is noninvasive and point-of-care, which shows great development potential in the health examination and monitoring field.
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Affiliation(s)
- Yanfang Guan
- School of Electromechanical Engineering, Henan University of Technology, Zhengzhou 450001, China
- Provincial Key Laboratory of Cereal Resource Transformation and Utilization, Henan University of Technology, Zhengzhou 450001, China
| | - Lei Liu
- School of Electromechanical Engineering, Henan University of Technology, Zhengzhou 450001, China
| | - Shaobo Yu
- School of Electromechanical Engineering, Henan University of Technology, Zhengzhou 450001, China
| | - Feng Lv
- School of Electromechanical Engineering, Henan University of Technology, Zhengzhou 450001, China
| | - Mingshuo Guo
- School of Electromechanical Engineering, Henan University of Technology, Zhengzhou 450001, China
| | - Qing Luo
- School of Electromechanical Engineering, Henan University of Technology, Zhengzhou 450001, China
| | - Shukai Zhang
- School of Electromechanical Engineering, Henan University of Technology, Zhengzhou 450001, China
| | - Zongcai Wang
- School of Electromechanical Engineering, Henan University of Technology, Zhengzhou 450001, China
| | - Lan Wu
- School of Electromechanical Engineering, Henan University of Technology, Zhengzhou 450001, China
| | - Yang Lin
- Department of Mechanical, Industrial & Systems Engineering, University of Rhode Island, Kingston, RI 02881, USA
| | - Guangyu Liu
- Provincial Key Laboratory of Cereal Resource Transformation and Utilization, Henan University of Technology, Zhengzhou 450001, China
- School of Chemistry and Chemical Engineering, Henan University of Technology, Zhengzhou 450001, China
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Asarani NAM, Reynolds AN, Boucher SE, de Bock M, Wheeler BJ. Cutaneous Complications With Continuous or Flash Glucose Monitoring Use: Systematic Review of Trials and Observational Studies. J Diabetes Sci Technol 2020; 14:328-337. [PMID: 31452386 PMCID: PMC7196864 DOI: 10.1177/1932296819870849] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
BACKGROUND Continuous glucose monitoring (CGM)/flash glucose monitoring (FGM) use in diabetes management is increasing. Cutaneous complications associated with these devices were reported. We conducted a systematic review to provide an overview of cutaneous complications with CGM/FGM use. METHODS We identified observational studies and intervention trials that report on cutaneous complications with CGM/FGM use up to January 14, 2019. Studies were identified through Medline, Embase, and PubMed, or with hand searching of the previous publications. Screening was duplicated and data extracted to consider four main themes: incidence rate and severity, participant perspectives of cutaneous complications, potential solutions, and future directions in diabetic technology relevant to reducing cutaneous complications. RESULTS A total of 54 eligible studies were identified. The overall event rate of cutaneous complications reported from 19 trials was one event per eight weeks of sensor wear-time of which 1.5% were considered severe. The most common cutaneous complications were wear-related erythema, itching, and induration. Although skin irritations were the most common cause of CGM/FGM discontinuation, most users experienced less pain or discomfort with CGM/FGM than capillary blood glucose testing. Future technological advances may reduce, but not eliminate cutaneous complications. CONCLUSION The incidence rate of reported cutaneous complications with CGM/FGM use from the available literature is low, with one event per eight weeks of sensor wear-time. Reported complication severity was also low, leading to low rates of CGM/FGM discontinuation. However, there appear to be discrepancies between reporting in trial and observational data. Greater constancy in reporting is necessary to understand the frequency of this issue.
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Affiliation(s)
- Nurul A. Mohd Asarani
- Department of Women’s and Children’s
Health, Dunedin School of Medicine, University of Otago, New Zealand
| | - Andrew N. Reynolds
- Department of Medicine, Dunedin School
of Medicine, University of Otago, New Zealand
| | - Sara E. Boucher
- Department of Women’s and Children’s
Health, Dunedin School of Medicine, University of Otago, New Zealand
| | - Martin de Bock
- Department of Paediatrics, University of
Otago, Christchurch
| | - Benjamin J. Wheeler
- Department of Women’s and Children’s
Health, Dunedin School of Medicine, University of Otago, New Zealand
- Benjamin J. Wheeler, MBChB, PhD, Department
of Women’s and Children’s Health, Dunedin School of Medicine, University of
Otago, PO Box 56, Dunedin, Otago 9022, New Zealand.
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Cheng J, Ji Z, Li M, Dai J. Study of a noninvasive blood glucose detection model using the near-infrared light based on SA-NARX. Biomed Signal Process Control 2020. [DOI: 10.1016/j.bspc.2019.101694] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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6
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Zhang C, Zhang Z, Yang Q, Chen W. Graphene-based Electrochemical Glucose Sensors: Fabrication and Sensing Properties. ELECTROANAL 2018. [DOI: 10.1002/elan.201800522] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Chunmei Zhang
- State Key Laboratory of Electroanalytical Chemistry; Changchun Institute of Applied Chemistry; Chinese Academy of Sciences; Changchun, Jilin 130022 China
- University of Chinese Academy of Sciences; Beijing 100039 China
| | - Ziwei Zhang
- State Key Laboratory of Electroanalytical Chemistry; Changchun Institute of Applied Chemistry; Chinese Academy of Sciences; Changchun, Jilin 130022 China
- University of Science and Technology of China; Hefei 230029, Anhui China
| | - Qin Yang
- School of Science; Xi'an University of Architecture & Technology; Xi'an 710055 China
| | - Wei Chen
- State Key Laboratory of Electroanalytical Chemistry; Changchun Institute of Applied Chemistry; Chinese Academy of Sciences; Changchun, Jilin 130022 China
- University of Science and Technology of China; Hefei 230029, Anhui China
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Gnana kumar G, Amala G, Gowtham SM. Recent advancements, key challenges and solutions in non-enzymatic electrochemical glucose sensors based on graphene platforms. RSC Adv 2017. [DOI: 10.1039/c7ra02845h] [Citation(s) in RCA: 79] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
This review elucidates the recent advances in graphene platforms in electrochemical non-enzymatic glucose sensors and provides solutions for existing bottlenecks.
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Affiliation(s)
- G. Gnana kumar
- Department of Physical Chemistry
- School of Chemistry
- Madurai Kamaraj University
- Madurai 625 021
- India
| | - G. Amala
- Department of Physical Chemistry
- School of Chemistry
- Madurai Kamaraj University
- Madurai 625 021
- India
| | - S. M. Gowtham
- School of Chemistry
- Madurai Kamaraj University
- Madurai 625 021
- India
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Camou S. Phase Difference Optimization of Dual-Wavelength Excitation for the CW-Photoacoustic-Based Noninvasive and Selective Investigation of Aqueous Solutions of Glucose. SENSORS 2015. [PMID: 26198230 PMCID: PMC4541882 DOI: 10.3390/s150716358] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Towards the noninvasive and continuous monitoring of blood glucose levels, we chose the continuous-wave photoacoustic (CW-PA) technique and developed the optical power balance shift (OPBS) method. However, operating with optical wavelengths in the near-infrared (NIR) region ensures deep penetration inside human soft-tissue, but also leads to two serious issues: strong background level noise from water molecules in this wavelength range and small differences between the absorbance spectra of diluted compounds. To resolve them, the OPBS method relies on simultaneous optical excitation at two wavelengths for differential measurements. However, the first validation in vitro with calibrated aqueous solutions of glucose and albumin revealed strong dependence on the phase difference between the two lights sources. In this paper, we report a systematic investigation of this parameter, from PA-based measurements over a wide range of phase differences and an extensive characterization in the frequency domain. The process of maintaining the phase quadrature of the two optical signals is demonstrated in real time through an analysis of the PA signal and therefore does not require any additional equipment. Finally, a comparison of aqueous glucose solution characterizations at high concentration levels with the two methods was performed and consistent results were obtained.
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Affiliation(s)
- Serge Camou
- NTT Device Technology Laboratories, NTT Corporation, Atsugi 243-0198, Japan.
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Ultrasound-enhanced transdermal delivery: recent advances and future challenges. Ther Deliv 2015; 5:843-57. [PMID: 25287389 DOI: 10.4155/tde.14.32] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
The skin is a formidable diffusion barrier that restricts passive diffusion to small (<500 Da) lipophilic molecules. Methods used to permeabilize this barrier for the purpose of drug delivery are maturing as an alternative to oral drug delivery and hypodermic injections. Ultrasound can reversibly and non-invasively permeabilize the diffusion barrier posed by the skin. This review discusses the mechanisms of ultrasound-permeability enhancement, and presents technological innovations in equipment miniaturization and recent advances in permeabilization capabilities. Additionally, potentially exciting applications, including protein delivery, vaccination, gene therapy and sensing of blood analytes, are discussed. Finally, the future challenges and opportunities associated with the use of ultrasound are discussed. It is stressed that developing ultrasound for suitable applications is key to ensure commercial success.
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Yadav J, Rani A, Singh V, Murari BM. Prospects and limitations of non-invasive blood glucose monitoring using near-infrared spectroscopy. Biomed Signal Process Control 2015. [DOI: 10.1016/j.bspc.2015.01.005] [Citation(s) in RCA: 94] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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11
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Multivariate calibration of NIR spectroscopic sensors for continuous glucose monitoring. Trends Analyt Chem 2015. [DOI: 10.1016/j.trac.2014.12.005] [Citation(s) in RCA: 82] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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12
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Fetal membrane transport enhancement using ultrasound for drug delivery and noninvasive detection. Pharm Res 2014; 32:403-13. [PMID: 25079390 DOI: 10.1007/s11095-014-1470-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2014] [Accepted: 07/24/2014] [Indexed: 10/25/2022]
Abstract
PURPOSE The purpose of this research was to evaluate the effect of ultrasound on mass transport across fetal membrane for direct fetal drug delivery and sensing of the amniotic fluid in a noninvasive manner. METHODS Post-delivery human fetal membranes (chorioamnion) were used for in vitro experiments, in which the effect of ultrasound on transport across fetal membrane of fluorescent model molecule (250 kDa) was evaluated. Ex vivo experiments were carried out on a whole rat amniotic sac. The model molecule or alpha-fetoprotein was injected into the amniotic sac through the placenta. Transport of these molecules across pre- and post-insonation of the amniotic sac was evaluated. The ultrasound enhancement's mechanism was also assessed. RESULTS The greatest enhancement in mass transport (43-fold) in vitro was achieved for 5 min of insonation (20 kHz, 4.6 W/cm(2), 5 mm distance). Ex vivo results showed a rapid increase (23-fold) in mass transport of the model molecule and also for alphafetoprotein following 30 s of insonation (20 kHz, 4.6 W/cm(2), 5 mm distance). CONCLUSIONS Mass transport across fetal membranes was enhanced post-insonation both in vitro and ex vivo in a reversible and transient manner. We suggest that exterior (to the amniotic sac) ultrasound-induced cavitation is the main mechanism of action.
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Azagury A, Khoury L, Enden G, Kost J. Ultrasound mediated transdermal drug delivery. Adv Drug Deliv Rev 2014; 72:127-43. [PMID: 24463344 DOI: 10.1016/j.addr.2014.01.007] [Citation(s) in RCA: 133] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2013] [Revised: 12/24/2013] [Accepted: 01/14/2014] [Indexed: 01/06/2023]
Abstract
Transdermal drug delivery offers an attractive alternative to the conventional drug delivery methods of oral administration and injections. However, the stratum corneum serves as a barrier that limits the penetration of substances to the skin. Application of ultrasound (US) irradiation to the skin increases its permeability (sonophoresis) and enables the delivery of various substances into and through the skin. This review presents the main findings in the field of sonophoresis in transdermal drug delivery as well as transdermal monitoring and the mathematical models associated with this field. Particular attention is paid to the proposed enhancement mechanisms and future trends in the fields of cutaneous vaccination and gene therapy.
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Affiliation(s)
- Aharon Azagury
- Department of Chemical Engineering, Ben-Gurion University, Beer-Sheva 84105, Israel
| | - Luai Khoury
- Department of Biomedical Engineering, Ben-Gurion University, Beer-Sheva 84105, Israel
| | - Giora Enden
- Department of Biomedical Engineering, Ben-Gurion University, Beer-Sheva 84105, Israel
| | - Joseph Kost
- Department of Chemical Engineering, Ben-Gurion University, Beer-Sheva 84105, Israel.
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Jina A, Tierney MJ, Tamada JA, McGill S, Desai S, Chua B, Chang A, Christiansen M. Design, development, and evaluation of a novel microneedle array-based continuous glucose monitor. J Diabetes Sci Technol 2014; 8:483-7. [PMID: 24876610 PMCID: PMC4455438 DOI: 10.1177/1932296814526191] [Citation(s) in RCA: 103] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The development of accurate, minimally invasive continuous glucose monitoring (CGM) devices has been the subject of much work by several groups, as it is believed that a less invasive and more user-friendly device will result in greater adoption of CGM by persons with insulin-dependent diabetes. This article presents the results of preliminary clinical studies in subjects with diabetes of a novel prototype microneedle-based continuous glucose monitor. In this device, an array of tiny hollow microneedles is applied into the epidermis from where glucose in interstitial fluid (ISF) is transported via passive diffusion to an amperometric glucose sensor external to the body. Comparison of 1396 paired device glucose measurements and fingerstick blood glucose readings for up to 72-hour wear in 10 diabetic subjects shows the device to be accurate and well tolerated by the subjects. Overall mean absolute relative difference (MARD) is 15% with 98.4% of paired points in the A+B region of the Clarke error grid. The prototype device has demonstrated clinically accurate glucose readings over 72 hours, the first time a microneedle-based device has achieved such performance.
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Affiliation(s)
| | | | | | | | | | | | - Anna Chang
- John Muir Physician Network Clinical Research Center, Concord, CA USA
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Scuffi C. Interstitium versus Blood Equilibrium in Glucose Concentration and its Impact on Subcutaneous Continuous Glucose Monitoring Systems. EUROPEAN ENDOCRINOLOGY 2014; 10:36-42. [PMID: 29872462 PMCID: PMC5983095 DOI: 10.17925/ee.2014.10.01.36] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2013] [Accepted: 02/13/2014] [Indexed: 12/18/2022]
Abstract
The relationship between both interstitial and blood glucose remains a debated topic, on which there is still no consensus. The experimental evidence suggests that blood and interstitial fluid glucose levels are correlated by a kinetic equilibrium, which as a consequence has a time and magnitude gradient in glucose concentration between blood and interstitium. Furthermore, this equilibrium can be perturbed by several physiological effects (such as foreign body response, wound-healing effect, etc.), with a consequent reduction of interstitial fluid glucose versus blood glucose correlation. In the present study, the impact of operating in the interstitium on continuous glucose monitoring systems (CGMs) will be discussed in depth, both for the application of CGMs in the management of diabetes and in other critical areas, such as tight glycaemic control in critically ill patients.
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Affiliation(s)
- Cosimo Scuffi
- Scientist, Scientific and Technology Affairs Department, A. Menarini Diagnostics, Florence, Italy
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Mitragotri S. Engineering approaches to transdermal drug delivery: a tribute to contributions of prof. Robert Langer. Skin Pharmacol Physiol 2013; 26:263-76. [PMID: 23921113 DOI: 10.1159/000351947] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2013] [Accepted: 04/08/2013] [Indexed: 11/19/2022]
Abstract
Transdermal drug delivery continues to provide an advantageous route of drug administration over injections. While the number of drugs delivered by passive transdermal patches has increased over the years, no macromolecule is currently delivered by the transdermal route. Substantial research efforts have been dedicated by a large number of researchers representing varied disciplines including biology, chemistry, pharmaceutics and engineering to understand, model and overcome the skin's barrier properties. This article focuses on engineering contributions to the field of transdermal drug delivery. The article pays tribute to Prof. Robert Langer, who pioneered the engineering approach towards transdermal drug delivery. Over a period spanning nearly 25 years since his first publication in the field of transdermal drug delivery, Bob Langer has deeply impacted the field by quantitative analysis and innovative engineering. At the same time, he has inspired several generations of engineers by collaborations and mentorship. His scientific insights, innovative technologies, translational efforts and dedicated mentorship have transformed the field.
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Affiliation(s)
- S Mitragotri
- Department of Chemical Engineering, University of California, Santa Barbara, CA 93106, USA.
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Camou S, Haga T, Tajima T, Tamechika E. Detection of aqueous glucose based on a cavity size- and optical-wavelength-independent continuous-wave photoacoustic technique. Anal Chem 2012; 84:4718-24. [PMID: 22548281 DOI: 10.1021/ac203331w] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Toward the achievement of noninvasive and continuous monitoring of blood glucose level, we developed a new measurement method based on the continuous-wave photoacoustic (CW-PA) technique and performed the first validation in vitro with calibrated aqueous glucose solutions. The PA technique has been studied in the past but exclusively based on the pulse setup since the CW one exhibits dependence on the cavity dimensions, which is not compatible with the final application requirements. This paper describes a new strategy relying on the monitoring of the resonant-frequency relative shift induced by the change of glucose concentrations rather than amplitude signal levels at a fixed frequency. From in vitro results, we demonstrate a stable and reproducible response to glucose at various cavity dimensions and optical wavelengths, with a slope of 0.19 ±0.01%/g/dL. From theoretical considerations, this method is consistent with a relative acoustic velocity measurement, which also explains the aforementioned stability. The proposed method then resolves most of the issues usually associated with the CW-PA technique and makes it a potential alternative for the noninvasive and continuous monitoring of glycemia levels. However, experimental determination of sensor responses to albumin and temperature as two potential interferents shows similar levels, which points to the selectivity to glucose as a major issue we should deal with in future development.
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Affiliation(s)
- S Camou
- Microsystem Integration Laboratories, Microsensor Research Group, NTT Corp., Atsugi, Japan.
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18
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Sampling of disease biomarkers from skin for theranostic applications. Drug Deliv Transl Res 2012; 2:87-94. [DOI: 10.1007/s13346-012-0061-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Polat BE, Hart D, Langer R, Blankschtein D. Ultrasound-mediated transdermal drug delivery: mechanisms, scope, and emerging trends. J Control Release 2011; 152:330-48. [PMID: 21238514 PMCID: PMC3436072 DOI: 10.1016/j.jconrel.2011.01.006] [Citation(s) in RCA: 248] [Impact Index Per Article: 19.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2010] [Accepted: 01/07/2011] [Indexed: 10/18/2022]
Abstract
The use of ultrasound for the delivery of drugs to, or through, the skin is commonly known as sonophoresis or phonophoresis. The use of therapeutic and high frequencies of ultrasound (≥0.7MHz) for sonophoresis (HFS) dates back to as early as the 1950s, while low-frequency sonophoresis (LFS, 20-100kHz) has only been investigated significantly during the past two decades. Although HFS and LFS are similar because they both utilize ultrasound to increase the skin penetration of permeants, the mechanisms associated with each physical enhancer are different. Specifically, the location of cavitation and the extent to which each process can increase skin permeability are quite dissimilar. Although the applications of both technologies are different, they each have strengths that could allow them to improve current methods of local, regional, and systemic drug delivery. In this review, we will discuss the mechanisms associated with both HFS and LFS, specifically concentrating on the key mechanistic differences between these two skin treatment methods. Background on the relevant physics associated with ultrasound transmitted through aqueous media will also be discussed, along with implications of these phenomena on sonophoresis. Finally, a thorough review of the literature is included, dating back to the first published reports of sonophoresis, including a discussion of emerging trends in the field.
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Affiliation(s)
- Baris E. Polat
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Douglas Hart
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Robert Langer
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Daniel Blankschtein
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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Polat BE, Blankschtein D, Langer R. Low-frequency sonophoresis: application to the transdermal delivery of macromolecules and hydrophilic drugs. Expert Opin Drug Deliv 2011; 7:1415-32. [PMID: 21118031 DOI: 10.1517/17425247.2010.538679] [Citation(s) in RCA: 106] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
IMPORTANCE OF THE FIELD Transdermal delivery of macromolecules provides an attractive alternative route of drug administration when compared to oral delivery and hypodermic injection because of its ability to bypass the harsh gastrointestinal tract and deliver therapeutics non-invasively. However, the barrier properties of the skin only allow small, hydrophobic permeants to traverse the skin passively, greatly limiting the number of molecules that can be delivered via this route. The use of low-frequency ultrasound for the transdermal delivery of drugs, referred to as low-frequency sonophoresis (LFS), has been shown to increase skin permeability to a wide range of therapeutic compounds, including both hydrophilic molecules and macromolecules. Recent research has demonstrated the feasibility of delivering proteins, hormones, vaccines, liposomes and other nanoparticles through LFS-treated skin. In vivo studies have also established that LFS can act as a physical immunization adjuvant. LFS technology is already clinically available for use with topical anesthetics, with other technologies currently under investigation. AREAS COVERED IN THIS REVIEW This review provides an overview of mechanisms associated with LFS-mediated transdermal delivery, followed by an in-depth discussion of the current applications of LFS technology for the delivery of hydrophilic drugs and macromolecules, including its use in clinical applications. WHAT THE READER WILL GAIN The reader will gain an insight into the field of LFS-mediated transdermal drug delivery, including how the use of this technology can improve on more traditional drug delivery methods. TAKE HOME MESSAGE Ultrasound technology has the potential to impact many more transdermal delivery platforms in the future due to its unique ability to enhance skin permeability in a controlled manner.
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Affiliation(s)
- Baris E Polat
- Massachusetts Institute of Technology, Department of Chemical Engineering, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
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Keenan DB, Mastrototaro JJ, Voskanyan G, Steil GM. Delays in minimally invasive continuous glucose monitoring devices: a review of current technology. J Diabetes Sci Technol 2009; 3:1207-14. [PMID: 20144438 PMCID: PMC2769894 DOI: 10.1177/193229680900300528] [Citation(s) in RCA: 114] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Through the use of enzymatic sensors-inserted subcutaneously in the abdomen or ex vivo by means of microdialysis fluid extraction-real-time minimally invasive continuous glucose monitoring (CGM) devices estimate blood glucose by measuring a patient's interstitial fluid (ISF) glucose concentration. Signals acquired from the interstitial space are subsequently calibrated with capillary blood glucose samples, a method that has raised certain questions regarding the effects of physiological time lags and of the duration of processing delays built into these devices. The time delay between a blood glucose reading and the value displayed by a continuous glucose monitor consists of the sum of the time lag between ISF and plasma glucose, in addition to the inherent electrochemical sensor delay due to the reaction process and any front-end signal processing delays required to produce smooth traces. Presented is a review of commercially available, minimally invasive continuous glucose monitors with manufacturer reported device delays. The data acquisition process for the Medtronic MiniMed (Northridge, CA) continuous glucose monitoring system-CGMS Gold-and the Guardian RT monitor is described with associated delays incurred for each processing step. Filter responses for each algorithm are examined using in vitro hypoglycemic and hyperglycemic clamps, as well as with an analysis of fast glucose excursions from a typical meal response. Results demonstrate that the digital filters used by each algorithm do not cause adverse effects to fast physiologic glucose excursions, although nonphysiologic signal characteristics can produce greater delays.
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Abstract
OBJECTIVES Use of ultrasound in therapeutics and drug delivery has gained importance in recent years, evident by the increase in patents filed and new commercial devices launched. The present review discusses new advancements in sonophoretic drug delivery in the last two decades, and highlights important challenges still to be met to make this technology of more use in the alleviation of diseases. KEY FINDINGS Phonophoretic research often suffers from poor calibration in terms of the amount of ultrasound energy emitted, and therefore current research must focus on safety of exposure to ultrasound and miniaturization of devices in order to make this technology a commercial reality. More research is needed to identify the role of various parameters influencing sonophoresis so that the process can be optimized. Establishment of long-term safety issues, broadening the range of drugs that can be delivered through this system, and reduction in the cost of delivery are issues still to be addressed. SUMMARY Sonophoresis (phonophoresis) has been shown to increase skin permeability to various low and high molecular weight drugs, including insulin and heparin. However, its therapeutic value is still being evaluated. Some obstacles in transdermal sonophoresis can be overcome by combination with other physical and chemical enhancement techniques. This review describes recent advancements in equipment and devices for phonophoresis, new formulations tried in sonophoresis, synergistic effects with techniques such as chemical enhancers, iontophoresis and electroporation, as well as the growing use of ultrasound in areas such as cancer therapy, cardiovascular disorders, temporary modification of the blood-brain barrier for delivery of imaging and therapeutic agents, hormone replacement therapy, sports medicine, gene therapy and nanotechnology. This review also lists patents pertaining to the formulations and techniques used in sonophoretic drug delivery.
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Affiliation(s)
- Rekha Rao
- M. M. College of Pharmacy, M. M. University, Mullana, 133001, India
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Abstract
Glucose monitoring technology has been used in the management of diabetes for three decades. Traditional devices use enzymatic methods to measure glucose concentration and provide point sample information. More recently continuous glucose monitoring devices have become available providing more detailed data on glucose excursions. In future applications the continuous glucose sensor may become a critical component of the closed loop insulin delivery system and, as such, must be selective, rapid, predictable and acceptable for continuous patient use. Many potential sensing modalities are being pursued including optical and transdermal techniques. This review aims to summarize existing technology, the methods for assessing glucose sensing devices and provide an overview of emergent sensing modalities.
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Affiliation(s)
- N S Oliver
- Institute of Biomedical Engineering, Imperial College, London, UK.
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Abstract
Transdermal drug delivery has made an important contribution to medical practice, but has yet to fully achieve its potential as an alternative to oral delivery and hypodermic injections. First-generation transdermal delivery systems have continued their steady increase in clinical use for delivery of small, lipophilic, low-dose drugs. Second-generation delivery systems using chemical enhancers, noncavitational ultrasound and iontophoresis have also resulted in clinical products; the ability of iontophoresis to control delivery rates in real time provides added functionality. Third-generation delivery systems target their effects to skin's barrier layer of stratum corneum using microneedles, thermal ablation, microdermabrasion, electroporation and cavitational ultrasound. Microneedles and thermal ablation are currently progressing through clinical trials for delivery of macromolecules and vaccines, such as insulin, parathyroid hormone and influenza vaccine. Using these novel second- and third-generation enhancement strategies, transdermal delivery is poised to significantly increase its impact on medicine.
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Affiliation(s)
- Mark R Prausnitz
- School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, 311 Ferst Dr., Atlanta, Georgia 30332-0100, USA.
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25
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Abstract
Transdermal drug delivery has made an important contribution to medical practice, but has yet to fully achieve its potential as an alternative to oral delivery and hypodermic injections. First-generation transdermal delivery systems have continued their steady increase in clinical use for delivery of small, lipophilic, low-dose drugs. Second-generation delivery systems using chemical enhancers, noncavitational ultrasound and iontophoresis have also resulted in clinical products; the ability of iontophoresis to control delivery rates in real time provides added functionality. Third-generation delivery systems target their effects to skin's barrier layer of stratum corneum using microneedles, thermal ablation, microdermabrasion, electroporation and cavitational ultrasound. Microneedles and thermal ablation are currently progressing through clinical trials for delivery of macromolecules and vaccines, such as insulin, parathyroid hormone and influenza vaccine. Using these novel second- and third-generation enhancement strategies, transdermal delivery is poised to significantly increase its impact on medicine.
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Chuang H, Trieu MQ, Hurley J, Taylor EJ, England MR, Nasraway SA. Pilot studies of transdermal continuous glucose measurement in outpatient diabetic patients and in patients during and after cardiac surgery. J Diabetes Sci Technol 2008; 2:595-602. [PMID: 19885235 PMCID: PMC2769762 DOI: 10.1177/193229680800200410] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
BACKGROUND We tested the hypothesis that glucose can be measured continuously and reliably in patients in diverse settings using a transdermal biosensor coupled to a permeated skin site. In addition, we compared a novel, abrasion-based skin permeation method to an ultrasound-based method for transdermal continuous glucose monitoring. METHOD Transdermal continuous glucose monitors were applied to patients with diabetes (study I), patients undergoing cardiac surgery (study II), and healthy volunteers (study III). Reference blood glucose measurements were performed with glucometers or standard blood glucose analyzers. At the conclusion of the 24-hour study, data were postprocessed for comparison with the reference blood glucose values collected during the study period. RESULTS Data were validated for 10 subjects for 12 hours in study I, 8 subjects for 24 hours in study II, and 6 subjects in study III. The transdermal continuous glucose monitors usually required 1 hour of warm up. Depending on the study setting, single or multiple calibrations were applied to the datasets. Comparing predicted glucose versus reference blood glucose values, we found that study I yielded 89.6% in zone A and 9.0% in zone B in the Clarke error grid (222 data points), study II yielded 86.4% in zone A and 13.6% in zone B (147 data points), and study III yielded 89.9% in zone A and 10.1% in zone B (378 data points). CONCLUSIONS Continuous transdermal glucose monitoring was demonstrated successfully in diverse clinical settings. The performance of abrasion was equivalent to ultrasound skin permeation methodology for transdermal glucose monitoring.
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Affiliation(s)
- Han Chuang
- Echo Therapeutics, Incorporation, Franklin, Massachusetts
| | - My-Quyen Trieu
- Echo Therapeutics, Incorporation, Franklin, Massachusetts
| | - James Hurley
- Echo Therapeutics, Incorporation, Franklin, Massachusetts
| | | | - Michael R. England
- Department of Anesthesia, Tufts University School of Medicine, Boston, Massachusetts
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27
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Ogura M, Paliwal S, Mitragotri S. Low-frequency sonophoresis: current status and future prospects. Adv Drug Deliv Rev 2008; 60:1218-23. [PMID: 18450318 DOI: 10.1016/j.addr.2008.03.006] [Citation(s) in RCA: 94] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2008] [Accepted: 03/04/2008] [Indexed: 10/22/2022]
Abstract
Application of ultrasound enhances skin permeability to drugs, a phenomenon referred to as sonophoresis. Significant strides have been made in sonophoresis research in recent years, especially under low-frequency conditions (20 kHz<f<100 kHz). This article reviews the mechanistic principles and current status of sonophoresis under low-frequency conditions. Several therapeutic macromolecules including insulin, low-molecular weight heparin, and vaccines have been delivered using low-frequency sonophoresis in vivo. Clinical trials have been performed with several drugs including lidocaine and cyclosporin. Novel theoretical and experimental approaches have provided insights into the mechanisms of low-frequency sonophoresis. Current understanding of these mechanisms is presented.
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Tura A, Maran A, Pacini G. Non-invasive glucose monitoring: assessment of technologies and devices according to quantitative criteria. Diabetes Res Clin Pract 2007; 77:16-40. [PMID: 17141349 DOI: 10.1016/j.diabres.2006.10.027] [Citation(s) in RCA: 127] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/06/2006] [Accepted: 10/25/2006] [Indexed: 10/23/2022]
Abstract
Aim of this review was to describe the main technologies for non-invasive glucose monitoring and the corresponding most relevant devices. The review tries to overcome the limitations of previous reviews on this topic, such as the lack of objective criteria for inclusion or exclusion of technologies or devices, and the poor organization of the information, which often does not allow easy comparison between technologies and devices. In this review, the information is concise and organized into specific categories, and hence it becomes easy to compare advantages and disadvantages of the different technologies and devices. For technologies, the categories of information considered are the technology name, the underlying physical principle, the technology limitations and the measurement sites on the human body. For devices, the categories of information are the device name, its approval condition (FDA Approval and/or CE Mark), the technology on which it is based, a device general description, the tests performed on the device, the corresponding results, safety information, aspects affecting usability, current status of the device and the manufacturer, an Internet reference for the device. A total of 14 technologies and 16 devices are included. Conclusions of the review were that, despite some interesting and promising technologies and devices, a satisfactory solution to the non-invasive glucose monitoring problem still requires further efforts.
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Kondepati VR, Heise HM. Recent progress in analytical instrumentation for glycemic control in diabetic and critically ill patients. Anal Bioanal Chem 2007; 388:545-63. [PMID: 17431594 DOI: 10.1007/s00216-007-1229-8] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2006] [Revised: 02/16/2007] [Accepted: 02/22/2007] [Indexed: 01/08/2023]
Abstract
Implementing strict glycemic control can reduce the risk of serious complications in both diabetic and critically ill patients. For this reason, many different analytical, mainly electrochemical and optical sensor approaches for glucose measurements have been developed. Self-monitoring of blood glucose (SMBG) has been recognised as being an indispensable tool for intensive diabetes therapy. Recent progress in analytical instrumentation, allowing submicroliter samples of blood, alternative site testing, reduced test time, autocalibration, and improved precision, is comprehensively described in this review. Continuous blood glucose monitoring techniques and insulin infusion strategies, developmental steps towards the realization of the dream of an artificial pancreas under closed loop control, are presented. Progress in glucose sensing and glycemic control for both patient groups is discussed by assessing recent published literature (up to 2006). The state-of-the-art and trends in analytical techniques (either episodic, intermittent or continuous, minimal-invasive, or noninvasive) detailed in this review will provide researchers, health professionals and the diabetic community with a comprehensive overview of the potential of next-generation instrumentation suited to either short- and long-term implantation or ex vivo measurement in combination with appropriate body interfaces such as microdialysis catheters.
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Affiliation(s)
- Venkata Radhakrishna Kondepati
- ISAS--Institute for Analytical Sciences at the University of Dortmund, Bunsen-Kirchhoff-Strasse 11, 44139, Dortmund, Germany
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Lavon I, Grossman N, Kost J, Kimmel E, Enden G. Bubble growth within the skin by rectified diffusion might play a significant role in sonophoresis. J Control Release 2006; 117:246-55. [PMID: 17197050 DOI: 10.1016/j.jconrel.2006.10.027] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2006] [Revised: 10/13/2006] [Accepted: 10/24/2006] [Indexed: 10/23/2022]
Abstract
Low frequency ultrasound has successfully been used for enhancing transdermal transport of a variety of different molecules. This phenomenon is referred to as sonophoresis. Several attempts have been made to investigate the enhancing mechanism in order to modulate the overall process. In this study we assess whether rectified diffusion is a process that occurs within the skin, which could eventually lead to channeling and thereby to transdermal sonophoresis. The model presented in this paper is based on the following postulate: gas bubbles are randomly distributed within the lipid bilayers of the stratum corneum (SC). As the skin is subjected to ultrasound, gas bubbles grow by rectified diffusion. During this period, bubbles may merge with the outer or inner boundaries of the SC, or merge with neighboring bubbles. Eventually, channels are created, allowing drugs to easily penetrate through the most significant barrier to transdermal delivery, the SC. As a result, transdermal transport rate is enhanced. In this work, a mathematical model has been formulated, in which permeability enhancement of the SC is linked to channels, possibly created by means of rectified diffusion. Sonophoresis may result from various mechanisms that act in synergy. The present model predicts that rectified diffusion might be one of the factors that lead to sonophoresis during ultrasound treatment.
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Affiliation(s)
- Ilana Lavon
- Department of Chemical Engineering, Ben Gurion University of the Negev, Beer Sheva, Israel
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Lee S, Nayak V, Dodds J, Pishko M, Smith NB. Glucose measurements with sensors and ultrasound. ULTRASOUND IN MEDICINE & BIOLOGY 2005; 31:971-7. [PMID: 15972203 DOI: 10.1016/j.ultrasmedbio.2005.04.004] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2005] [Revised: 03/30/2005] [Accepted: 04/07/2005] [Indexed: 05/03/2023]
Abstract
Accurate monitoring of the blood glucose level in diabetics is essential in preventing complications. Generally, conventional over-the-counter glucose meters require frequent painful finger punctures to obtain samples, which makes a noninvasive method preferable. The purpose of this study was to demonstrate that glucose levels can be measured transdermally with the combination of the low-profile cymbal array and an electrochemical glucose sensor consisting of amperometric electrodes and a novel glucose oxidase hydrogel. Interstitial fluid glucose concentrations can be determined with the electrochemical glucose sensor after the skin is made permeable to glucose by ultrasound (US) (20 kHz) with the thin (< 7 mm) and light (< 22 g) cymbal array. Using this array to deliver insulin into hyperglycemic rats, our previous experiments demonstrated that blood glucose levels would decrease 233.3 mg/dl with 5 min of US exposure. With the sensor and array, our goal was to determine the glucose levels of hyperglycemic rats noninvasively and evaluate the possible bioeffects. A total of 12 anesthetized rats were placed into two groups (US exposure group and control group) and the array (I(SPTP) = 100 mW/cm(2)) with a saline reservoir operating for 20 min was affixed to the abdomen. The array was removed and an electrochemical glucose sensor was placed on the exposed area to determine the glucose concentrations through the skin. Comparison was made using a commercial glucose meter with the blood collected from a jugular vein. The average blood glucose level determined by the sensor was 356.0 +/- 116.6 mg/dl, and the glucose level measured by the commercial glucose meter was 424.8 +/- 59.1 mg/dl. These results supported the use of this novel system consisting of the electrochemical glucose sensor and the cymbal array for glucose monitoring.
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Affiliation(s)
- Seungjun Lee
- Department of Bioengineering, College of Engineering, The Pennsylvania State University, University Park, PA 16802, USA
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Sieg A, Guy RH, Delgado-Charro MB. Noninvasive and minimally invasive methods for transdermal glucose monitoring. Diabetes Technol Ther 2005; 7:174-97. [PMID: 15738715 DOI: 10.1089/dia.2005.7.174] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Noninvasive and minimally invasive techniques for monitoring glucose via the skin are reviewed. These approaches rely either on the interaction of electromagnetic radiation with the tissue or on the extraction of fluid across the barrier. The structure and physiology of the skin make the technical realization of transdermal glucose monitoring a difficult challenge. The techniques involving transdermal fluid extraction circumvent and/or compromise the barrier function of skin's outermost and least permeable layer, the stratum corneum, by the application of physical energy. While sonophoresis and microporation methods, for example, are in relatively early-stage development, a device using reverse iontophoresis [the GlucoWatch Biographer (Cygnus, Inc., Redwood City, CA)] is already commercially available. Optical techniques to monitor glucose are truly noninvasive. The tissue is irradiated, the absorbed or scattered radiation is analyzed, and the information is processed, to provide a measure proportional to the concentration of glucose in the dermal tissue. These techniques include near-infrared and Raman spectroscopy, polarimetry, light scattering, and photoacoustic spectroscopy. By contrast, impedance spectroscopy measures changes in the dielectric properties of the tissue induced by blood glucose variation. Large-scale studies in support of efficacy of these methodologies are as yet unavailable. At present, therefore, transdermal fluid extraction technologies are offering greater promise in terms of practical and realizable devices for patient use. The truly noninvasive allure of the optical approach assures continued and intense research activity--for the moment, however, an affordable, efficient, and portable system is not on the immediate horizon.
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Affiliation(s)
- Anke Sieg
- School of Pharmacy, University of Geneva, Geneva, Switzerland
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34
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Abstract
Transdermal drug delivery offers an attractive alternative to the conventional drug delivery methods of oral administration and injection. However, the stratum corneum acts as a barrier that limits the penetration of substances through the skin. Application of ultrasound to the skin increases its permeability (sonophoresis) and enables the delivery of various substances into and through the skin. This review presents the main findings in the field of sonophoresis, namely transdermal drug delivery and transdermal monitoring. Particular attention is paid to proposed enhancement mechanisms and future trends in the field of cutaneous vaccination and gene delivery.
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Affiliation(s)
- Ilana Lavon
- Department of Chemical Engineering, Ben-Gurion University of the Negev, POB 653, Beer-Sheva, Israel
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