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1.
Lab Chip ; 18(6): 933-943, 2018 03 13.
Article in English | MEDLINE | ID: mdl-29459934

ABSTRACT

Three dimensional cell culture systems have witnessed rapid expansion in the fields of tissue engineering and drug testing owing to their inherent ability to mimic native tissue microenvironments. High throughput technologies have also facilitated rapid and reproducible generation of spheroids and subsequently their use as in vitro tissue models in drug screening platforms. However, drug screening technologies are in need of monitoring platforms to study these 3D culture models. In this work we present a novel platform to measure the electrical impedance of 3D spheroids, through the use of a planar organic electrochemical transistor (OECT) and a novel circular-shaped microtrap. A new strategy was generated to overcome incompatibility of the integration of polydimethylsiloxane (PDMS) microdevices with OECT fabrication. The impedance platform for 3D spheroids was tested by using spheroids formed from mono-cultures of fibroblast and epithelial cells, as well as co-culture of the two cell types. We validated the platform by showing its ability to measure the spheroid resistance (Rsph) of the 3D spheroids and differences in Rsph were found to be related to the ion permeability of the spheroid. Additionally, we showed the potential use of the platform for the on-line Rsph monitoring when a co-culture spheroid was exposed to a porogenic agent affecting the integrity of the cell membrane.


Subject(s)
Dimethylpolysiloxanes/chemistry , Electrochemical Techniques , Spheroids, Cellular , Coculture Techniques , Electric Impedance , Electrochemical Techniques/instrumentation , Epithelial Cells/cytology , Fibroblasts/cytology , Humans
2.
Analyst ; 143(3): 715-724, 2018 Jan 29.
Article in English | MEDLINE | ID: mdl-29336454

ABSTRACT

This paper presents the use of tubing to store clinical microdialysis samples for delayed analysis with high temporal resolution, offering an alternative to traditional discrete offline microdialysis sampling. Samples stored in this way were found to be stable for up to 72 days at -80 °C. Examples of how this methodology can be applied to glucose and lactate measurement in a wide range of in vivo monitoring experiments are presented. This paper presents a general model, which allows for an informed choice of tubing parameters for a given storage time and flow rate avoiding high back pressure, which would otherwise cause the microdialysis probe to leak, while maximising temporal resolution.

3.
J Mater Chem B ; 6(18): 2901-2906, 2018 May 14.
Article in English | MEDLINE | ID: mdl-32254243

ABSTRACT

Organic electrochemical transistors (OECTs) are being intensively developed for applications in electronics and biological interfacing. These devices rely on ions injected in a polymer film from an aqueous liquid electrolyte for their operation. However, the development of solid or semi-solid electrolytes are needed for future integration of OECTs into flexible, printed or conformable bioelectronic devices. Here, we present a new polyethylene glycol hydrogel with high Na+ conductivity which is particularly suitable for OECTs. This novel hydrogel was synthesized using cost-effective photopolymerization of poly(ethylene glycol)-dimethacrylate and sodium acrylate. Due to the high water content (83% w/w) and the presence of free Na+, the hydrogel showed high ionic conductivity values at room temperature (10-2 S cm-1) as characterized by electrochemical impedance spectroscopy. OECTs made using this hydrogel as a source of ions showed performance that was equivalent to that of OECTs employing a liquid electrolyte. They also showed improved stability, with only a 3% drop in current after 6 h of operation. This hydrogel paves the way for the replacement of liquid electrolytes in high performance OECTs bringing about advantages in terms of device integration and protection.

6.
Rev Enferm ; 21(233): 49-55, 1998 Jan.
Article in Spanish | MEDLINE | ID: mdl-9534569

ABSTRACT

In these days of concern for the growing costs of medical care it is an opportune moment to promote the importance of nurses as health care professionals and the roles that they play. This article presents a structural care plan for specific clinical situations regarding lens surgery with the goal of both guaranteeing quality nursing care and a method to evaluate costs. Lens surgery, a equently performed operation in the hospital, is used as an example to evaluate criteria of adequate service and efficiency. This method is based upon L.J. Caronito s bifocal model of clinical nursing.


Subject(s)
Cataract Extraction/nursing , Lens, Crystalline/surgery , Patient Care Planning/organization & administration , Perioperative Nursing , Cataract Extraction/economics , Cost Control , Humans , Models, Nursing , Total Quality Management/organization & administration
7.
Minerva Urol Nefrol ; 49(3): 133-6, 1997 Sep.
Article in Italian | MEDLINE | ID: mdl-9432735

ABSTRACT

BACKGROUND: In the course of Continuous Veno-Venous Hemofiltration (CVVH), bicarbonate buffer instead of lactate is suitable for the treatment of combined renal and hepatic failure and for patients suffering from lactic acidosis, type A or B, joined with acute renal failure (ARF). METHODS: We applied the CVVH buffered with bicarbonate for the treatment of two patients affected by ARF and severe lactic acidosis type B (due to biguanide intoxication) and we evaluated its ability to correct the acid-base balance. RESULTS: Clinical and laboratory data show that this technique, performed in standard conditions (plasma flow: 70 ml/min, ultrafiltration: 25 ml/min, bicarbonate concentration in the infusion fluid: 30 mEq/L), was inadequate to compensate for the high requirement of bicarbonate (approximately 280 mEq/hr during the first 6 hours of observation) and the severe metabolic acidosis, thus additional bicarbonate infusion was needed. CONCLUSIONS: In particular, from ascertained data and theoretical considerations, in the course of lactic acidosis caused by biguanide, in order to correct acidosis a positive balance of bicarbonate could be obtained only by means of a bicarbonate-based replacement fluid and of a continuous high flow hemofiltration, such as to assure an ultrafiltrate volume exceeding 150 ml/min.


Subject(s)
Acidosis, Lactic/blood , Bicarbonates/blood , Bicarbonates/therapeutic use , Fluid Therapy , Hemofiltration/methods , Hypoglycemic Agents/adverse effects , Phenformin/adverse effects , Acidosis, Lactic/chemically induced , Acute Kidney Injury/blood , Acute Kidney Injury/therapy , Aged , Bicarbonates/administration & dosage , Buffers , Diabetes Mellitus, Type 2/complications , Diabetes Mellitus, Type 2/drug therapy , Drug Therapy, Combination , Fatal Outcome , Female , Humans
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