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1.
Appl Opt ; 57(32): 9705-9713, 2018 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-30461756

RESUMO

In this paper, we present, to the best of our knowledge, the first low-loss vacuum-compatible thermally controlled Faraday isolator able to retain a good isolation factor under high-vacuum working conditions. The throughput that can be obtained with the developed device is as high as 99%, retaining an isolation factor higher than 40 dB. That very high isolation ratio can be kept over long time periods independently from external temperature conditions with a few Celsius degrees of variation due to thermal active control. The mechanical and optical configuration is detailed, and the performances achieved with this device are presented.

2.
Artigo em Inglês | MEDLINE | ID: mdl-38535985

RESUMO

Coronary artery bypass grafting has evolved considerably since it was introduced approximately 50 years ago, with continuously improved patient outcomes as a result of this growth. The most up-to-date evidence on topics such as graft patency, grafting strategy, approaches to graft harvesting, minimally invasive coronary artery bypass grafting, and postoperative pharmacotherapy may lead to changes in current accepted practice. In addition, several unanswered questions in the field of coronary artery bypass grafting may benefit from further investigation and, if resolved, might advance the field and change practice. Current or upcoming clinical trials seek to answer these unanswered questions and may generate data that yields improved outcomes and quality of life for all patients after coronary artery bypass grafting. In addition, cutting edge clinical trials designed specifically for women and racial and ethnic minorities who have had poorer outcomes and have traditionally been underrepresented in cardiovascular surgery research, have recently been launched that may change the way that a large portion of the coronary artery bypass grafting population is treated in the future.

3.
ASAIO J ; 2024 Jun 17.
Artigo em Inglês | MEDLINE | ID: mdl-38875452

RESUMO

The presence of adhesions and patent bypass grafts may create challenges for standard 14 mm outflow graft placement during left ventricular assist device implantation. We retrospectively describe our experience using a 10 mm Bioline Fusion graft (Getinge, Goteborg, Sweden) as the outflow graft in patients undergoing primary Heartmate 3 (Abbott, Abbott Park, IL) implantation. One hundred one patients underwent Heartmate 3 left ventricular assist device implantation, 80% via a thoracotomy approach, with the standard 14 mm outflow graft (78) or a 10 mm Bioline Fusion outflow graft (23). Initial postoperative rotor speed-to-flow ratio (the revolutions per minutes (RPMs) required to achieve a given flow) was significantly higher in 10 mm graft patients (1,472 vs. 1,283 RPM/L/min; p = 0.03), suggesting elevated resistance in the smaller graft. Furthermore, the initial postoperative vasoactive-inotrope score was higher in the 10 mm graft patients (24.1 vs. 17.6; p = 0.022). Postoperative outcomes were similar between groups. In conclusion, the use of a 10 mm graft was associated with higher RPMs needed to generate a given flow and a higher vasoactive-inotrope score, but these differences were not associated with increased right ventricular failure or mortality.

4.
Eur J Cardiothorac Surg ; 66(2)2024 Aug 02.
Artigo em Inglês | MEDLINE | ID: mdl-39133169

RESUMO

OBJECTIVES: Clinical trials that are terminated prematurely may generate incomplete and potentially biased data and the reasons for premature trials termination are poorly understood. Our objective was to describe the incidence of premature trial termination and identify factors associated with it. METHODS: We performed a systematic search on ClinicalTrials.gov to identify all cardiac surgery trials from 1991 to 2023. Trials that were terminated prematurely were identified. Factors independently associated with premature termination were identified using multivariable logistic regression analysis. RESULTS: A total of 746 clinical trials were included; of them 577 were completed and 169 (22.6%) were terminated prematurely. Most of the trials originated from North America [294 (39.4%)], Europe [264 (35.4%)] or Asia [141 (18.9%)]. Fourteen of the trials terminated prematurely (8.3%) were phase 1, 75 (44.4%) phase 2, 49 (29.0%) phase 3 and 31 (18.3%) phase 4. Fifty (29.6%) trials were terminated because of slow recruitment, 20 (11.8%) because of sponsor decision and 12 (7.1%) because of lack of funding. Left ventricular assist device trials [odds ratio (OR) 3.65, 95% confidence interval (CI) (1.65-8.00) P = 0.001], valve surgery trials [OR 4.30, 95% CI (2.33-8.00) P < 0.001], aortic surgery trials [OR 2.86 95% CI (1.22-6.43) P = 0.012], phase 2 [OR 3.02, 95% CI (1.31-7.93) P = 0.015] and phase 4 trials [OR 3.62, 95% CI (1.43-10.23) P = 0.010] were at higher risk of premature termination while trials performed in Asia [OR 0.18, 95% CI (0.07-0.39) P ≤ 0.001] and Europe [OR 0.49, 95% CI (0.30-0.80) P = 0.004] were less likely to be terminated prematurely. CONCLUSIONS: Slow recruitment is the most common reason for premature termination of cardiac surgery trials. Trials on left ventricular assist device, valve surgery, aortic surgery, phase 2 trials and phase 4 trials are more likely to be terminated, while trials conducted in Asia and Europe are less likely to be terminated prematurely.


Assuntos
Procedimentos Cirúrgicos Cardíacos , Término Precoce de Ensaios Clínicos , Humanos , Procedimentos Cirúrgicos Cardíacos/estatística & dados numéricos , Ensaios Clínicos como Assunto/estatística & dados numéricos , Bases de Dados Factuais
5.
Int J Surg ; 110(9): 5795-5801, 2024 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-38847774

RESUMO

BACKGROUND: Postoperative bleeding requiring re-exploration is a serious complication that occurs in 2.8-4.6% of patients undergoing cardiac surgery. Re-exploration has previously been associated with a higher risk of short-term mortality. However, a comprehensive analysis of long-term outcomes after re-exploration for bleeding has not been published. MATERIALS AND METHODS: The authors performed a systematic, three databases search to identify studies reporting long-term outcomes in patients who required re-exploration for bleeding after cardiac surgery compared to patients who did not, with at least 1-year of follow-up. Long-term survival was the primary outcome. Secondary outcomes were operative mortality, myocardial infarction, stroke, renal and respiratory complications, and hospital length of stay. Random-effects models was used. Individual patient survival data was extracted from available survival curves and reconstructed using restricted mean survival time. RESULTS: Six studies totaling 135 456 patients were included. The average follow-up was 5.5 years. In the individual patient data, patients who required re-exploration had a significantly higher risk of death compared with patients who did not [hazard ratio (HR): 1.21; 95% CI: 1.14-1.27; P <0.001], which was confirmed by the study-level survival analysis (HR: 1.32; 95% CI: 1.12-1.56; P <0.01). Re-exploration was also associated with a higher risk of operative mortality [odds ratio (OR): 5.25, 95% CI: 4.74-5.82, P <0.0001], stroke (OR: 2.05, 95% CI: 1.72-2.43, P <0.0001), renal (OR: 4.13, 95% CI: 3.43-4.39 P <0.0001) respiratory complications (OR: 3.91, 95% CI: 2.96-5.17, P <0.0001), longer hospital length of stay (mean difference: 2.69, 95% CI: 1.68-3.69, P <0.0001), and myocardial infarction (OR: 1.85, 95% CI: 1.30-2.65, P =0.0007). CONCLUSION: Postoperative bleeding requiring re-exploration is associated with lower long-term survival and increased risk of short-term adverse events including operative mortality, stroke, renal and respiratory complications, and longer hospital length of stay. To improve both short-term and long-term outcomes, strategies to prevent the need for re-exploration are necessary.


Assuntos
Procedimentos Cirúrgicos Cardíacos , Hemorragia Pós-Operatória , Reoperação , Humanos , Procedimentos Cirúrgicos Cardíacos/efeitos adversos , Procedimentos Cirúrgicos Cardíacos/mortalidade , Reoperação/estatística & dados numéricos , Reoperação/mortalidade , Hemorragia Pós-Operatória/mortalidade , Hemorragia Pós-Operatória/epidemiologia , Hemorragia Pós-Operatória/etiologia , Adulto
6.
Artigo em Inglês | MEDLINE | ID: mdl-38842243

RESUMO

INTRODUCTION: Lipoprotein(a) (Lp[a]) is a variant of low-density lipoprotein (LDL) and has been associated with increased risk of vascular inflammation and thrombosis. Coronary artery bypass grafting (CABG) has been associated with local inflammation of the myocardium. It is plausible, therefore, that patients with elevated baseline Lp(a) may be prone to unfavorable clinical outcomes following CABG. We evaluate differences in outcomes between CABG patients with high and low serum Lp(a) in this meta-analysis. EVIDENCE ACQUISITION: A comprehensive literature search was performed to identify studies reporting outcomes in CABG patients stratified by preoperative Lp(a) level. When possible, the outcomes were pooled in a meta-analysis. We assessed post-operative mortality, major cardiovascular events, stroke occurrence and saphenous graft occlusion. EVIDENCE SYNTHESIS: Eight studies involving 8681 patients were included. Articles used varying cut-offs for high versus low Lp(a), and outcomes varied. In the three studies evaluating mortality, two showed no statistically significant difference between groups while one reported increased mortality associated with high Lp(a) level. Both studies investigating major adverse cardiovascular events reported higher risk in patients with high Lp(a). A study-level meta-analysis of four studies reporting saphenous vein graft occlusion incidence after CABG was performed. High (≥30 mg/dL) preoperative Lp(a) was not associated with an increased risk of graft occlusion compared with low (<30 mg/dL) preoperative Lp(a) (OR=1.88, 95% CI: 0.66-5.36; P=0.15). CONCLUSIONS: Studies evaluating the impact of Lp(a) on outcomes in CABG patients are few, with heterogenous cut-offs and outcomes. In the limited published studies, Lp(a) level was not associated with graft occlusion.

7.
JTCVS Open ; 18: 64-79, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38690432

RESUMO

Background: Subclinical hypothyroidism (SCH) is associated with major adverse cardiovascular events. Despite the recognized negative impact of SCH on cardiovascular health, research on cardiac postoperative outcomes with SCH has yielded conflicting results, and patients are not currently treated for SCH before cardiac surgery procedures. Methods: We performed a study-level meta-analysis on the impact of SCH on patients undergoing nonurgent cardiac surgery, including coronary artery bypass grafting and valve and aortic surgery. The primary outcome was operative mortality. Secondary outcomes were hospital length of stay (LOS), intensive care unit (ICU) stay, postoperative atrial fibrillation (POAF), intra-aortic balloon pump (IABP) use, renal complications, and long-term all-cause mortality. Results: Seven observational studies, with a total of 3445 patients, including 851 [24.7%] diagnosed with SCH and 2594 [75.3%] euthyroid patients) were identified. Compared to euthyroid patients, the patients with SCH had higher rates of operative mortality (odds ratio [OR], 2.57; 95% confidence interval [CI], 1.09-6.04; P = .03), prolonged hospital LOS (standardized mean difference, 0.32; 95% CI, 0.02-0.62; P = .04), a higher rate of renal complications (OR, 2.53; 95% CI, 1.74-3.69; P < .0001), but no significant differences in ICU stay, POAF, or IABP use. At mean follow-up of 49.3 months, the presence of SCH was associated with a higher rate of all-cause mortality (incidence rate ratio, 1.82; 95% CI, 1.18-2.83; P = .02). Conclusions: Patients with SCH have higher operative mortality, prolonged hospital LOS, and increased renal complications after cardiac surgery. Achieving and maintaining a euthyroid state prior to and after cardiac surgery procedures might improve outcomes in these patients.

8.
Eur J Cardiothorac Surg ; 65(6)2024 Jun 03.
Artigo em Inglês | MEDLINE | ID: mdl-38830050

RESUMO

OBJECTIVES: The association between obesity and graft failure after coronary artery bypass grafting has not been previously investigated. METHODS: We pooled individual patient data from randomized clinical trials with systematic postoperative coronary imaging to evaluate the association between obesity and graft failure at the individual graft and patient levels. Penalized cubic regression splines and mixed-effects multivariable logistic regression models were performed. RESULTS: Six trials comprising 3928 patients and 12 048 grafts were included. The median time to imaging was 1.03 (interquartile range 1.00-1.09) years. By body mass index (BMI) category, 800 (20.4%) patients were normal weight (BMI 18.5-24.9), 1668 (42.5%) were overweight (BMI 25-29.9), 983 (25.0%) were obesity class 1 (BMI 30-34.9), 344 (8.8%) were obesity class 2 (BMI 35-39.9) and 116 (2.9%) were obesity class 3 (BMI 40+). As a continuous variable, BMI was associated with reduced graft failure [adjusted odds ratio (aOR) 0.98 (95% confidence interval (CI) 0.97-0.99)] at the individual graft level. Compared to normal weight patients, graft failure at the individual graft level was reduced in overweight [aOR 0.79 (95% CI 0.64-0.96)], obesity class 1 [aOR 0.81 (95% CI 0.64-1.01)] and obesity class 2 [aOR 0.61 (95% CI 0.45-0.83)] patients, but not different compared to obesity class 3 [aOR 0.94 (95% CI 0.62-1.42)] patients. Findings were similar, but did not reach significance, at the patient level. CONCLUSIONS: In a pooled individual patient data analysis of randomized clinical trials, BMI and obesity appear to be associated with reduced graft failure at 1 year after coronary artery bypass grafting.


Assuntos
Índice de Massa Corporal , Ponte de Artéria Coronária , Obesidade , Sobrepeso , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Ponte de Artéria Coronária/efeitos adversos , Obesidade/complicações , Sobrepeso/complicações , Sobrepeso/epidemiologia , Ensaios Clínicos Controlados Aleatórios como Assunto , Fatores de Risco
9.
J Cardiovasc Dev Dis ; 10(11)2023 Nov 07.
Artigo em Inglês | MEDLINE | ID: mdl-37998511

RESUMO

Saphenous vein grafts (SVGs) are the most frequently used conduits in coronary artery bypass grafting (CABG), but their higher rate of occlusion compared to arterial conduits remains a concern. Previous studies have shown that SVG failure is mainly driven by intimal hyperplasia, an adaptative response to higher pressures of the arterial circulation. The VESTTM device (Vascular Graft Solutions, Tel Aviv, Israel), an external support designed to mitigate intimal hyperplasia in SVGs, has been tested in few clinical trials (RCTs). Herein, we descriptively evaluated the randomized evidence on the VEST device.

10.
Sensors (Basel) ; 12(5): 6520-37, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22778656

RESUMO

We report on the electrochemical detection of anti-cancer drugs in human serum with sensitivity values in the range of 8-925 nA/µM. Multi-walled carbon nanotubes were functionalized with three different cytochrome P450 isoforms (CYP1A2, CYP2B6, and CYP3A4). A model used to effectively describe the cytochrome P450 deposition onto carbon nanotubes was confirmed by Monte Carlo simulations. Voltammetric measurements were performed in phosphate buffer saline (PBS) as well as in human serum, giving well-defined current responses upon addition of increasing concentrations of anti-cancer drugs. The results assert the capability to measure concentration of drugs in the pharmacological ranges in human serum. Another important result is the possibility to detect pairs of drugs present in the same sample, which is highly required in case of therapies with high side-effects risk and in anti-cancer pharmacological treatments based on mixtures of different drugs. Our technology holds potentials for inexpensive multi-panel drug-monitoring in personalized therapy.


Assuntos
Antineoplásicos/sangue , Neoplasias da Mama/sangue , Sistema Enzimático do Citocromo P-450/química , Técnicas Eletroquímicas/métodos , Nanotubos de Carbono , Antineoplásicos/uso terapêutico , Técnicas Biossensoriais , Neoplasias da Mama/tratamento farmacológico , Feminino , Humanos , Microscopia Eletrônica de Varredura
11.
Sensors (Basel) ; 12(8): 11013-60, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-23112644

RESUMO

Recent advances in microelectronics and biosensors are enabling developments of innovative biochips for advanced healthcare by providing fully integrated platforms for continuous monitoring of a large set of human disease biomarkers. Continuous monitoring of several human metabolites can be addressed by using fully integrated and minimally invasive devices located in the sub-cutis, typically in the peritoneal region. This extends the techniques of continuous monitoring of glucose currently being pursued with diabetic patients. However, several issues have to be considered in order to succeed in developing fully integrated and minimally invasive implantable devices. These innovative devices require a high-degree of integration, minimal invasive surgery, long-term biocompatibility, security and privacy in data transmission, high reliability, high reproducibility, high specificity, low detection limit and high sensitivity. Recent advances in the field have already proposed possible solutions for several of these issues. The aim of the present paper is to present a broad spectrum of recent results and to propose future directions of development in order to obtain fully implantable systems for the continuous monitoring of the human metabolism in advanced healthcare applications.


Assuntos
Técnicas Biossensoriais , Procedimentos Analíticos em Microchip , Monitorização Fisiológica , Próteses e Implantes , Animais , Engenharia Biomédica , Biotecnologia , Atenção à Saúde , Humanos , Nanotecnologia
12.
Ann Ital Chir ; 82(4): 267-72, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-21834475

RESUMO

AIM: To analyze GISTs behaviour observing their clinical evolution and outline the best approach to this neoplasia. MATERIAL OF STUDY: In a period between December 1999 and October 2009 came to our observation, at the Institute of General Surgery, 37 patients with GIST. We conducted a retrospective study evaluating the anatomo-pathological aspects, the clinical situation and the tumour characteristics of the 37 patients with GIST. RESULTS: The 37 patients included 21 women (57%) and 16 men (43%), the mean age was 67 years. GISTs originated from the stomach (27), jejunum (5), ileum (3), anus (1) and transverse mesocolon (1), the symptom most frequently found was acute anaemia and in 5 cases the diagnosis was occasional; 36 patients underwent surgical treatment. Based on tumor size, mitotic count, presence of areas of necrosis and/or haemorrhage, GISTs were classified according to the categories of potential high-grade malignancy (13 pts), intermediate grade (8 pts), low grade (16 pts). DISCUSSION: According to international literature, surgery remains the cornerstone of treatment for patients with primary resectable GIST without evidence of metastasis and should also be utilized when surgery has minimal risk of morbidity for the patient. The goal of surgery is complete surgical resection with negative margins (R0). The follow-up for some patients is still ongoing; only 10 patients underwent to adjuvant therapy with Imatinib. CONCLUSIONS: In the last decade, GISTs have become an emblematic example of the possibility of pharmacologically interfering with the molecular mechanisms of carcinogenesis.


Assuntos
Tumores do Estroma Gastrointestinal/cirurgia , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Fatores de Tempo
13.
Sci Rep ; 6: 22237, 2016 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-26928456

RESUMO

Google Glass is a recently designed wearable device capable of displaying information in a smartphone-like hands-free format by wireless communication. The Glass also provides convenient control over remote devices, primarily enabled by voice recognition commands. These unique features of the Google Glass make it useful for medical and biomedical applications where hands-free experiences are strongly preferred. Here, we report for the first time, an integral set of hardware, firmware, software, and Glassware that enabled wireless transmission of sensor data onto the Google Glass for on-demand data visualization and real-time analysis. Additionally, the platform allowed the user to control outputs entered through the Glass, therefore achieving bi-directional Glass-device interfacing. Using this versatile platform, we demonstrated its capability in monitoring physical and physiological parameters such as temperature, pH, and morphology of liver- and heart-on-chips. Furthermore, we showed the capability to remotely introduce pharmaceutical compounds into a microfluidic human primary liver bioreactor at desired time points while monitoring their effects through the Glass. We believe that such an innovative platform, along with its concept, has set up a premise in wearable monitoring and controlling technology for a wide variety of applications in biomedicine.


Assuntos
Dispositivos Lab-On-A-Chip/estatística & dados numéricos , Monitorização Fisiológica/métodos , Interface para o Reconhecimento da Fala , Telemedicina , Análise Atuarial , Técnicas Biossensoriais , Humanos , Técnicas Analíticas Microfluídicas , Controle de Qualidade , Smartphone , Telemedicina/tendências , Interface Usuário-Computador , Tecnologia sem Fio
14.
IEEE Trans Biomed Circuits Syst ; 10(5): 955-962, 2016 10.
Artigo em Inglês | MEDLINE | ID: mdl-28113177

RESUMO

This paper presents the in-vivo tests on a Fully Implantable Multi-Panel Devices for Remote Monitoring of endogenous and exogenous analytes. To investigate issues on biocompatibility, three different covers have been designed, realized and tested in mice for 30 days. ATP and neutrophil concentrations have been measured, at the implant site after the device was explanted, to assess the level of biocompatibility of the device. Finally, fully working prototypes of the device were implanted in mice and tested. The implanted devices were used to detect variations in the physiological concentrations of glucose and paracetamol. Data trends on these analytes have been successfully acquired and transmitted to the external base station. Glucose and paracetamol (also named acetaminophen) have been proposed in this research as model molecules for applications to personalized and translational medicine.


Assuntos
Acetaminofen/sangue , Técnicas Biossensoriais/instrumentação , Análise Química do Sangue/instrumentação , Glicemia/análise , Monitorização Ambulatorial/instrumentação , Próteses e Implantes , Tecnologia sem Fio/instrumentação , Animais , Condutometria/instrumentação , Desenho de Equipamento , Análise de Falha de Equipamento , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Miniaturização , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
15.
Gland Surg ; 4(6): 528-40, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26645007

RESUMO

Breast conservative therapy (BCT) is established as a safe option for most women with early breast cancer (BC). The best conservative mastectomy that can be performed, when mastectomy is unavoidable, is nipple-areola-complex sparing mastectomy (NSM), which allows the complete glandular dissection preserving the skin envelope and the nipple areola complex. In the treatment of BC, the cosmetic outcomes have become fundamental goals, as well as oncologic control. NSM is nowadays considered an alternative technique to improve the overall quality of life for women allowing excellent cosmetic results because it provides a natural appearing breast. The breast surgeon must pay attention to details and skin incision must be planned to minimize vascular impairment to the skin and the nipple. Preservation of the blood supply to the nipple is one of the most important concern during NSM because nipple or areolar necrosis is a well-described complication of this surgery. Another issue associated with the nipple preservation and the surgical technique is oncological safety related to nipple-areola-complex (NAC) involvement in patients with invasive BC. The authors present their experience on 252 NSM performed in the Breast Surgery Unit in Forlì. Careful selection of patients for this surgical procedure is imperative and many patients are not ideal candidates for this procedure because of concerns about nipple-areolar viability as women with significant large/ptotic breast, pre-existing breast scars and history of active cigarette smoking. To extend the benefits of nipple preservation to patients who are perceived to be at higher risk for nipple necrosis the authors describe technical modifications of NSM to allow nipple preservation and obtain good cosmetic outcomes.

16.
Int J Surg Case Rep ; 9: 19-22, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25706804

RESUMO

BACKGROUND: Desmoid tumors (DTs) is a benign tumor with high tendency to infiltrative evolution and recurrence. Nowadays, in abdominal localization, the standard approach is surgery with R0 condition. The need to repair post-surgical wide wall defect requires conservative technique to decrease the incidence of incisional hernia and to obtain better quality of life (QoL). METHODS: We perform an abdominal wall desmoid resection using ultrasound guide. This technique ensures to spare a wide wall area and to obtain a multilayer reconstruction minimizing postoperative risk. This approach allows good oncological results and better managing abdominal wall post-resection defect. RESULTS: We use US guided surgery to get radical approach and wall tissue spare that allows us a multilayer reconstruction minimizing post-operative complications. No recurrences were observed in one year follow up period. CONCLUSION: Our experience represents first step to consider ultrasound mediated technique usefull to optimize wall resection surgery and to minimize following complications.

17.
Artigo em Inglês | MEDLINE | ID: mdl-25570380

RESUMO

A multi-sensing platform for applications in wireless and batteryless monitoring of free-moving small animals is presented in this paper. The proposed platform hosts six sensors: four biosensors for sensing of both disease biomarkers and therapeutic compounds, and two further sensors (T and pH) for biosensor calibration. Electrodeposition of Multi-Walled Carbon Nanotubes (MWCNTs) and the subsequent function-alization with proper enzymes is used to assure sensitivity and specificity in electrochemical biosensing. The realized sensors are demonstrated to be capable of measuring several parameters: lactate with a sensitivity of 77±26 µA/mM· cm(2) and a limit of detection (LOD) of 4±1 µM; glucose with a sensitivity of 63±15 µA/mM· cm(2) and a LOD of 8±2 µM; Etoposide (a well known anti-cancer agent) with a sensitivity of 0.15±0.04 mA/mM· cm(2) and a LOD of 4±1 µM; Open Circuit Potential (OCP) measurements are used on a Pt/IrOx junction to sense pH with a sensitivity of around -75±5mV/pH; while a Pt resistive thermal device is used to measure physiological temperature-range with an average sensitivity of 0.108±0.001 kΩ/°C.


Assuntos
Fontes de Energia Elétrica , Técnicas Eletroquímicas/métodos , Monitorização Fisiológica/métodos , Movimento , Tecnologia sem Fio , Animais , Antineoplásicos/farmacologia , Calibragem , Eletrodos , Glucose/análise , Glucose Oxidase , Concentração de Íons de Hidrogênio , Limite de Detecção , Metaboloma , Camundongos , Temperatura
18.
IEEE Trans Biomed Circuits Syst ; 8(6): 891-8, 2014 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-24956394

RESUMO

We describe an integrated biosensor capable of sensing multiple molecular targets using both cyclic voltammetry (CV) and chronoamperometry (CA). In particular, we present our custom IC to realize voltage control and current readout of the biosensors. A mixed-signal circuit block generates sub-Hertz triangular waveform for the biosensors by means of a direct-digital-synthesizer to control CV. A current to pulse-width converter is realized to output the data for CA measurement. The IC is fabricated in 0.18 µm technology. It consumes 220 µW from 1.8 V supply voltage, making it suitable for remotely-powered applications. Electrical measurements show excellent linearity in sub- µA current range. Electrochemical measurements including CA measurements of glucose and lactate and CV measurements of the anti-cancer drug Etoposide have been acquired with the fabricated IC and compared with a commercial equipment. The results obtained with the fabricated IC are in good agreement with those of the commercial equipment for both CV and CA measurements.


Assuntos
Técnicas Biossensoriais , Técnicas Eletroquímicas , Eletrodos Implantados , Antineoplásicos Fitogênicos/análise , Técnicas Biossensoriais/instrumentação , Técnicas Biossensoriais/métodos , Técnicas Eletroquímicas/instrumentação , Técnicas Eletroquímicas/métodos , Etoposídeo/análise , Glucose/análise , Humanos , Ácido Láctico/análise
19.
IEEE Trans Nanobioscience ; 13(1): 19-30, 2014 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-24594511

RESUMO

We attempt to examine the potential of silicon nanowire memristors in the field of nanobiosensing. The memristive devices are crystalline Silicon (Si) Nanowires (NWs) with Nickel Silicide (NiSi) terminals. The nanowires are fabricated on a Silicon-on-Insulator (SOI) wafer by an Ebeam Lithography Technique (EBL) process that allows high resolution at the nanoscale. A Deep Reactive Ion Etching (DRIE) technique is used to define free-standing nanowires. The close alignment between Silicon (Si) and Nickel-Silicide (NiSi) terminals forms a Schottky-barrier at their junction. The memristive effect of the fabricated devices matches well with the memristor theory. An equivalent circuit reproducing the memristive effect in current-voltage (I-V) characteristics of our silicon nanowires is presented too. The memristive silicon nanowire devices are then functionalized with anti-human VEGF (Vascular Endothelial Growth Factor) antibody and I-V characteristics are examined for the nanowires prior to and after protein functionalization. The uptake of bio-molecules linked to the surface of the memristive NWs is confirmed by the increased voltage gap in the hysteresis curve. The effects of varying humidity conditions on the conductivity of bio-modified memristive silicon nanowires are deeply investigated.


Assuntos
Anticorpos/química , Técnicas Biossensoriais , Nanofios/química , Níquel/química , Compostos de Silício/química , Silício/química , Anticorpos/imunologia , Humanos , Umidade , Microscopia Eletrônica de Varredura , Modelos Teóricos , Nanofios/ultraestrutura , Imagem Óptica , Fator A de Crescimento do Endotélio Vascular/imunologia
20.
IEEE Trans Biomed Circuits Syst ; 8(5): 636-47, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-25314709

RESUMO

In this work, we show the realization of a fully-implantable device for monitoring free-moving small animals. The device integrates a microfabricated sensing platform, a coil for power and data transmission and two custom designed integrated circuits. The device is intended to be implanted in mice, free to move in a cage, to monitor the concentration of metabolites. We show the system level design of each block of the device, and we present the fabrication of the passive sensing platform and its employment for the electrochemical detection of endogenous and exogenous metabolites. Moreover, we describe the assembly of the device to test the biocompatibility of the materials used for the microfabrication. To ensure biocompatibility, an epoxy enhanced polyurethane membrane was used to cover the device. We proved through an in-vitro characterization that the membrane was capable to retain enzyme activity up to 35 days. After 30 days of implant in mice, in-vivo experiments proved that the membrane promotes the integration of the sensor with the surrounding tissue, as demonstrated by the low inflammation level at the implant site.


Assuntos
Técnicas Biossensoriais/instrumentação , Dispositivos Lab-On-A-Chip , Monitorização Fisiológica/instrumentação , Próteses e Implantes , Animais , Antineoplásicos/análise , Calibragem , Enzimas Imobilizadas , Desenho de Equipamento , Glucose/análise , Concentração de Íons de Hidrogênio , Limite de Detecção , Modelos Lineares , Masculino , Teste de Materiais , Camundongos , Camundongos Endogâmicos C57BL , Telemetria/instrumentação
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