Holographic Sensors in Biotechnology

Abstract

As populations expand worldwide, medical care will need to diversify its data collection techniques to be able to provide adequate healthcare to global populations, this can be achieved through point-of-care analysis by wearable analytical devices. Holographic sensors are reusable optical biosensors with the capability to continuously monitor variations, generating the prospect of in vivo monitoring of patient homeostasis. Holographic optical sensors have emerged as an opportunity for low cost and real-time point-of-care analysis of biomarkers to be realized. This review aims to summarize the fundamentals and fabrications of holographic sensors; a key focus will be directed to examining the biotechnology applications in a variety of analytical settings. Techniques covered include surface relief gratings, inverse opals, metal nanoparticle and nanoparticle free holographic sensors. This article provides an overview of holographic biosensing in applications such as pH, alcohol, ion, glucose, and drug detection, alongside antibiotic monitoring. Details of developments in fabrication and sensitizing techniques will be examined and how they have improved the applicability of holographic sensors to point-of-care analytics. Although holographic sensors have made significant progress in recent years, the current challenges, and requirements for advanced holographic technology to fulfil their future potential applications in biomedical devices will be discussed.

Hydrogel-based holographic sensors and biosensors: past, present, and future

“…Several previous articles refer to fabrication by holographic lithography that focus on the theoretical point of view and are based on photoresist materials [44] or, more interestingly, comprise all the materials employed in holographic sensors [42,43]. Here we briefly review the fabrication processes employed to date to create diffraction patterns on hydrogels.…”

“…Although previous reviews of holographic sensors have been published [42,43], they center on volume and phase holograms, or include different materials, like polymers or gelatin, which makes it difficult to distinguish the exact achievements and applications of hydrogel-based holographic systems. Here, we review the examples found in the literature that involve holographic lithography and responsive hydrogels, and focus on biosensors by analyzing their fabrication, measurement principles, and detection setups.…”

“…The selfassembly of highly charged colloidal particles followed by polymerization of acrylamide and bisacrylamide results in light diffraction because of the lattice spacing between crystal arrays. The incorporation of functional moieties into the polymer allows sensors to be created based on these diffraction gratings [42][43][44][45][46][47][48][49][50][51][52][53][54][55]. However, their fragility, together with their high sensitivity to environmental conditions, limits their wide application in this field.…”

Computational Modelling of Doubly‐Photopolymerized Holographic Biosensors

“…[ 4 ] Holographic sensors are ideally placed to facilitate the progression towards POC devices, due to their real‐time, label‐free readout, low cost, and reversibility. [ 5 ] Recent holographic technologies show a primary focus to biomedical applications, [ 6 ] such as sensing pH, [ 7 ] heavy metals, [ 8 ] glucose, [ 9 ] ions, [ 10 ] and lactate. [ 11 ] Holographic recordings can be constructed with additional information such as text to convey further information to users offering both qualitative visual analysis and quantitative measurements through the combination with smartphone applications.…”

On the Use of Haloalkane/Acrylate-Based Holographic Gratings as Compression and Rotation Sensors

“…In recent years, the well-established use of holographic gratings as sensors has led to many forms being developed in this research field. Surface relief gratings, inverse opals, metal nanoparticle and nanoparticle-free holographic sensors are used in medical and biological applications [ 1 ] or as humidity and temperature sensors [ 2 ], whereas flexible substrates are used for the detection of bending deformations [ 3 ] and pressure sensors [ 4 ]. Regarding pressure sensors, reflection phase holograms recorded in polymer mixtures are used to detect pressure changes by monitoring the reflection peak position as a function of the applied pressure.…”