Use of Silk Proteins to Form Organic, Flexible, Degradable Biosensors for Metabolite Monitoring

Abstract

The development of sustainable and degradable biosensors and bioelectronics has implications for implantable systems, as well in addressing issues of electronic waste. Mechanically flexible and bioresorbable sensors can find applications at soft biological interfaces. While devices typically use metallic and synthetic components and interconnects that are non-degradable or have the potential to cause adverse tissue reactions, the use of nature-derived materials and conducting polymers can provide distinct advantages. In particular, silk fibroin and sericin can provide a unique palette of properties, providing both structural and functional elements. Here, a fully organic, mechanically flexible biosensor in an integrated 3-electrode configuration is demonstrated. Silk sericin conducting ink is micropatterned on a silk fibroin substrate using a facile photolithographic process. Next, using a conducting polymer wire sheathed in silk fibroin, organic interconnects are used to form the electrical connections. This fully organic electrochemical system has competitive performance metrics for sensing in comparison to conventional systems, as verified by detection of a model analyte-ascorbic acid. The stability of the silk biosensor through biodegradation was observed, showing that the sensors can function for several days prior to failure. Such protein-based systems can provide a useful tool for biomonitoring of analytes in the body or environment for controlled periods of time, followed by complete degradation, as transient systems for various applications.

Sustainable Printed Electrochemical Platforms for Greener Analytics

“…Furthermore, the determination of glucose by the immobilization of GOx in the above-mentioned paste was accomplished with a LOD of 1.16 mM (Pal et al, 2016). Likewise, Xu et al (2019) compared the chronoamperometric response of such silk-proteins-based device ( Figure 2B) with a conventional one for the determination of AA, obtaining a LOD of 49.2 µM for the sericin/PEDOT-PSS-based device and 50.2 µM for the conventional one.…”

“… (A) 3D-printed 3-electrode integrated device made with PLA filaments, reprinted with permission from Katseli et al ( 2019 ); (B) PEDOT:PSS patterns on flexible silk fibroin sheets, reprinted with permission from Xu et al ( 2019 ); (C) Paper-based microfluidic electrochemical chip, reprinted with permission from Dungchai et al ( 2009 ). …”

Wearable Biosensors for Non-Invasive Sweat Diagnostics

“…As a result, our therapies will be more accurate since they rely on biomarkers rather than apparent symptoms [54][55][56][57]. Moreover, wearable bioelectronics can replace expensive and time-consuming lab tests with wearable diagnostic alternatives [58,59]. In traditional medical therapies or testing, many processes are involved, such as sample collection, preservation, and storage [60].…”

On the Secondary Structure of Silk Fibroin Nanoparticles Obtained Using Ionic Liquids: An Infrared Spectroscopy Study

“…This state is water-insoluble and presents all the impressive, well-known mechanical properties of silk [ 6 ]. The transition from silk I to silk II is easily achievable in the laboratory and the resulting regenerated silk can be used to produce many kinds of bioengineered materials [ 7 , 8 ] including but not limited to, bone fracture fixation devices [ 9 ], scaffolds for tissue engineering [ 10 , 11 , 12 ], biosensor [ 13 , 14 ], and nanoparticles for drug delivery applications [ 15 , 16 ]. The later has attracted considerable attention due to the SF nanoparticles’ (SFN) ability to load a wide variety of therapeutic compounds [ 17 ], enhance penetration [ 18 ] and the versatility of the SF matrix presents through chemical modification to program different functions into the nanoparticle [ 19 , 20 , 21 , 22 ].…”