Ratiometric Organic Fibers for Localized and Reversible Ion Sensing with Micrometer‐Scale Spatial Resolution

Abstract

A fundamental issue in biomedical and environmental sciences is the development of sensitive and robust sensors able to probe the analyte of interest, under physiological and pathological conditions or in environmental samples, and with very high spatial resolution. In this work, novel hybrid organic fibers that can effectively report the analyte concentration within the local microenvironment are reported. The nanostructured and flexible wires are prepared by embedding fluorescent pH sensors based on seminaphtho‐rhodafluor‐1‐dextran conjugate. By adjusting capsule/polymer ratio and spinning conditions, the diameter of the fibers and the alignment of the reporting capsules are both tuned. The hybrid wires display excellent stability, high sensitivity, as well as reversible response, and their operation relies on effective diffusional kinetic coupling of the sensing regions and the embedding polymer matrix. These devices are believed to be a powerful new sensing platform for clinical diagnostics, bioassays and environmental monitoring.

Probing the pH Microenvironment of Mesenchymal Stromal Cell Cultures on Additive‐Manufactured Scaffolds

“…In particular, monitoring pH during cell culture is essential for the maintenance of cellular viability and for improving tissue functions. [21] In tissue regeneration processes, the acid-base balance is fundamental for the remodeling process: in the specific case of bone, for example, metabolic acidosis causes calcium efflux, [22,23] while alkalosis decreases bone calcium efflux. [24,25] Despite numerous advances in the field of tissue engineering and regenerative medicine, monitoring the formation of tissue regeneration and its metabolic variations during culture is still a challenge and mostly limited to bulk volumetric assays.…”

“…In particular, monitoring pH during cell culture is essential for the maintenance of cellular viability and for improving tissue functions. [ 21 ] In tissue regeneration processes, the acid–base balance is fundamental for the remodeling process: in the specific case of bone, for example, metabolic acidosis causes calcium efflux, [ 22,23 ] while alkalosis decreases bone calcium efflux. [ 24,25 ] Consequently, extracellular acidosis promotes resorption, whereas alkalosis promotes formation/mineralization.…”

“…For colocalization analyses, a batch of capsules loaded only with FITC‐dextran was prepared by using the same procedure described here for synthesizing SNARF‐based capsules but replacing SNARF‐1‐dextran conjugate by FITC‐dextran conjugate. [ 21,53 ]…”

Microencapsulated fluorescent pH probe as implantable sensor for monitoring the physiological state of fish embryos

“…The ratio between the spectral peaks I 587 /I 627 of SNARF-1 inside MBMs has an apparent linear response to the pH of the media and was calibrated in a series of buffers from pH 6.6–8.4 ( Fig 1E ) before further in vivo measurements under a confocal microscope ( S1 Fig ). The response of microencapsulated SNARF-1 to pH is known to be highly reversible [ 38 ], which allow using this probe for prolonged pH monitoring.…”

Design and characterization of microcapsules-integrated collagen matrixes as multifunctional three-dimensional scaffolds for soft tissue engineering

“…In these approaches, the protein-loaded carriers can be easily added onto the prefabricated scaffolds or be added to the polymer phase while processing the scaffolds (Tessmar and Göpferich, 2007). Polymer capsules fabricated by the layer-by-layer (LbL) method are considered highly tunable delivery vehicles and easy to combine with other materials (De Luca et al, 2015;del Mercato et al, 2016del Mercato et al, , 2015del Mercato et al, , 2014Delcea et al, 2011;Kolbe et al, 2011;Wohl and Engbersen, 2012;Xiong et al, 2013). Biodegradable multilayer capsules integrated within 3D scaffolds would serve as containers of bioactive molecules that would allow for controlling the release of the payload and for protecting it from the surgical procedures (washing, debridement, bleeding, fluid aspiration) applied during the implantation of the scaffold which challenge the integrity of the material (De Cock et al, 2012;Facca et al, 2010;She et al, 2012).…”