Nanosensors for Visual Detection of Glucose in Biofluids: Are We Ready for Instrument-Free Home-Testing?

Abstract

Making frequent large-scale screenings for several diseases economically affordable would represent a real breakthrough in healthcare. One of the most promising routes to pursue such an objective is developing rapid, non-invasive, and cost-effective home-testing devices. As a first step toward a diagnostic revolution, glycemia self-monitoring represents a solid base to start exploring new diagnostic strategies. Glucose self-monitoring is improving people's life quality in recent years; however, current approaches still present vast room for improvement. In most cases, they still involve invasive sampling processes (i.e., finger-prick), quite discomforting for frequent measurements, or implantable devices which are costly and commonly dedicated to selected chronic patients, thus precluding large-scale monitoring. Thanks to their unique physicochemical properties, nanoparticles hold great promises for the development of rapid colorimetric devices. Here, we overview and analyze the main instrument-free nanosensing strategies reported so far for glucose detection, highlighting their advantages/disadvantages in view of their implementation as cost-effective rapid home-testing devices, including the potential use of alternative non-invasive biofluids as samples sources.

Keywords: POC; colorimetric test; glucose; home testing; instrument-free; nanosensors.

Figure 1

Scheme showing different biological fluids under investigation for their potential as glucose biosources in the development of home-testing systems and their relative physiological glucose concentration.

Figure 2

Examples of naked-eye nanosensing strategies for glucose detection including (a) etching (Reprinted with permission from Ref. [60]; Copyright 2021 Royal Society of Chemistry), (b) growing (Reprinted with permission from Ref. [66]; Copyright 2021 Royal Society of Chemistry), (c) nanozymes-chromogenic substrates (Reprinted with permission from Ref. [67]; Copyright 2021 John Wiley and Sons), (d) aggregation (Reprinted with permission from Ref. [82]; Copyright 2011 Analytical Chemistry), (e) reshaping [83], and (f) luminescent enhancement (Reprinted with permission from Ref. [84]; Copyright 2021 Elsevier). The color of the frames refers to the biological source used for the assay: (a–c) = blood, (d) = urine, (e) = saliva, (f) = tears. The Figure’s panels were adapted from the originals.