Recent Advances in Optical, Electrochemical and Field Effect pH Sensors

Vivaldi, Federico; Salvo, Pietro; Poma, Noemi; Bonini, Andrea; Biagini, Denise; Noce, Lorenzo Del; Melai, Bernardo; Lisi, Fabio; Francesco, Fabio Di

doi:10.3390/chemosensors9020033

Cited by 35 publications

(22 citation statements)

References 95 publications

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“…The main function of inorganic membranes has been as a support structure, by increasing the sensor surface area, to carry out a capillary action, or as mediators of fluid transport by capillary action. As mentioned in Table 1, glass membranes also are good examples of inorganic membranes that have been reported [38][39][40] for biosensor applications. In this table, more examples of inorganic membranes are given; nevertheless, the reports of organic membranes in sensing applications are much more numerous.…”

Section: Figure 3 Applications and Uses Of Membranes In Sensing Techn...mentioning

confidence: 99%

“…Aluminum or aluminum oxide [22][23][24][25] Gold [26][27][28] Silver [29][30][31] Titanium oxide [32][33][34] Silicon nitride [35][36][37] Glass membranes [38][39][40] Organic Cellulose nitrate, nitrocellulose, cellulose acetate…”

Section: Inorganicmentioning

confidence: 99%

“…Hence, it is not unusual to find hybrid membranes for sensing applications, which are composed of organic and inorganic components that effectively merge. This type of membrane can be of two types; (i) Organic membranes covered by a thin layer of inorganic material, usually, a conductor such as gold [31,[40][41][42][43][44][45]; and (ii) Membranes synthesized by sol-gel methods to obtain structures of inorganic nanoparticles with polymer chains [13,26,30,46]. Finally, composite membranes are multiple layers of membranes that are stacked together side-to-side or vertically to comprise a whole sensor [32][33][34][35][36][37][38]47].…”

Section: Inorganicmentioning

confidence: 99%

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Advanced Functional Membranes for Sensor Technologies

Hernández-Martínez

2022

Advanced Functional Membranes

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Sensors are modern data acquisition devices intended for detecting a specific change in the surrounding area and responding with an output signal. Among them, biological sensors (or biosensors) are of great interest due to their capacity for detecting molecules that indicate changes in people's health. This chapter provides an overview of the polymeric membranes that have novel or advanced functions in applications for the development of lab-on-chip or sensor technologies. Important approaches in this matter include the improvement of membranes as supporting medium of recognition element of the sensor, advances in membrane composition for protecting the integrity of target molecules, or the option to filter undesired components. The chapter is divided into three sections: membrane fabrication, molecular probes and platforms for reading sensor devices.

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Section: Figure 3 Applications and Uses Of Membranes In Sensing Techn...mentioning

confidence: 99%

Section: Inorganicmentioning

confidence: 99%

Section: Inorganicmentioning

confidence: 99%

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Advanced Functional Membranes for Sensor Technologies

Hernández-Martínez

2022

Advanced Functional Membranes

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“…Glass electrodes are the gold standard in the measurement of pH thanks to their wide range, reliability, precision and affordable price. However, they are limited by their minimum size (diameter > 1 mm in case of miniaturized electrodes), rigidity and interference with electrical current and electromagnetic fields [ 3 , 4 ]. Optical fibers used as sensors offer, on the other side, some advantages in special applications where properties such as small size, flexibility, remote detection or resistance to the electromagnetic field are desirable [ 4 ].…”

Section: Introductionmentioning

confidence: 99%

Ex-Vivo Measurement of the pH in Aqueous Humor Samples by a Tapered Fiber-Optic Sensor

Podrazký

Mrázek

Proboštová

et al. 2021

Sensors

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A practical demonstration of pH measurement in real biological samples with an in-house developed fiber-optic pH sensor system is presented. The sensor uses 8-hydroxypyrene-1,3,6-trisulfonate (HPTS) fluorescent dye as the opto-chemical transducer. The dye is immobilized in a hybrid sol-gel matrix at the tip of a tapered optical fiber. We used 405 nm and 450 nm laser diodes for the dye excitation and a photomultiplier tube as a detector. The sensor was used for the measurement of pH in human aqueous humor samples during cataract surgery. Two groups of patients were tested, one underwent conventional phacoemulsification removal of the lens while the other was subjected to femtosecond laser assisted cataract surgery (FLACS). The precision of the measurement was ±0.04 pH units. The average pH of the aqueous humor of patients subjected to FLACS and those subjected to phacoemulsification were 7.24 ± 0.17 and 7.31 ± 0.20 respectively.

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“…The potentiometric method is most commonly used for pH sensing and comprises a sensitive electrode and reference electrode. A redox reaction occurs at the metal oxide on the sensitive electrode surface in a solution; thus, detection is conducted through the measurement of the potential difference between the reference and sensitive electrodes in a solution of an unknown pH [ 18 ]. The main disadvantages of the potentiometric pH sensors are the difficulty of miniaturizing the reference electrode and the instability of the potential during long-term operation.…”

Section: Introductionmentioning

confidence: 99%

Effects of Buffer Concentration on the Sensitivity of Silicon Nanobelt Field-Effect Transistor Sensors

Wang

2021

Sensors

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In this work, a single-crystalline silicon nanobelt field-effect transistor (SiNB FET) device was developed and applied to pH and biomolecule sensing. The nanobelt was formed using a local oxidation of silicon technique, which is a self-aligned, self-shrinking process that reduces the cost of production. We demonstrated the effect of buffer concentration on the sensitivity and stability of the SiNB FET sensor by varying the buffer concentrations to detect solution pH and alpha fetoprotein (AFP). The SiNB FET sensor was used to detect a solution pH ranging from 6.4 to 7.4; the response current decreased stepwise as the pH value increased. The stability of the sensor was examined through cyclical detection under solutions with different pH; the results were stable and reliable. A buffer solution of varying concentrations was employed to inspect the sensing capability of the SiNB FET sensor device, with the results indicating that the sensitivity of the sensor was negatively dependent on the buffer concentration. For biomolecule sensing, AFP was sensed to test the sensitivity of the SiNB FET sensor. The effectiveness of surface functionalization affected the AFP sensing result, and the current shift was strongly dependent on the buffer concentration. The obtained results demonstrated that buffer concentration plays a crucial role in terms of the sensitivity and stability of the SiNB FET device in chemical and biomolecular sensing.

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Recent Advances in Optical, Electrochemical and Field Effect pH Sensors

Cited by 35 publications

References 95 publications

Advanced Functional Membranes for Sensor Technologies

Advanced Functional Membranes for Sensor Technologies

Ex-Vivo Measurement of the pH in Aqueous Humor Samples by a Tapered Fiber-Optic Sensor

Effects of Buffer Concentration on the Sensitivity of Silicon Nanobelt Field-Effect Transistor Sensors

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