Control of the Biodegradability of Piezoelectric Peptide Nanotubes Integrated with Hydrophobic Porphyrin

Abstract

Diphenylalanine (FF) is a piezoelectric material that is widely known for its high piezoelectric constant, self-assembly characteristics, and ease of manufacture. Because of its biocompatible nature, it is useful for implantable applications. However, its use in real applications is challenging because it degrades too easily in the body due to its solubility in water (0.76 g/mL). Upon incorporation of hydrophobic and biocompatible porphyrins into the FF, the degradability of the piezoelectric FF and their piezoelectric nanogenerators (PENGs) is controlled. Porphyrin-incorporated FFs are also formed as piezoelectric nanostructures well aligned on the substrate through self-assembly, and their piezoelectric properties are comparable to those of FF. The FF-based PENG degrades in only 5 min, whereas the FF-porphyrin-based PENG produces a stable output for >15 min in phosphate-buffered saline. This strategy for realizing biodegradable functional materials and devices with tunable degradation rates in the body can be applied to many implantable electronics.

Piezoelectric Micropower Harvester from Supramolecular Assembly of Chiral Ambipolar Chromophores

“…This observation is in line with the highest ferroelectricity and d 33 values as well as the high piezopotential distribution in the AD 2 A film, as discussed before. In comparison to recent reports (Table S2) − on high-performance organic piezoelectric energy harvesters (including polymers, copolymers, liquid crystals, biomaterials, and organic cocrystals), the values obtained with the present systems (Table ) are significantly higher than those of the noncrystalline supramolecular assemblies. The output values from the AD 2 A piezo harvester are further improved with vertical stacking using another identical piezo harvester ( V oc ≈ 3.7 V and P out ≈ 1.7 μW/cm 2 for two devices at 17 N and 5 Hz; due to the series connection of stacked piezodevices, the current did not increase), as they are assembled mechanically and electrically in series along the longitudinal direction (Figure S4).…”

“…Lately piezoelectric generators (nanogenerators for materials with nanoscale sizes) have attracted intense research focus due to their potential to collect energy from mechanical movements in the ambient environment or low-frequency body movements and physiological processes, which is essentially useful for waste microenergy harvesting or machinery/body vibration and pressure sensing. − Inorganic, crystalline piezoelectric ceramics have already found useful applications in mechanical transducers, but they undergo large permanent deformations within a very narrow range of impact force because of their rigid and brittle nature, are not easily malleable, and are rather costly. In this regard, molecular piezoelectric materials are promising due to their low processing temperature, mechanical flexibility, lower toxicity, light weight, and showing biocompatibility and biodegradability. − Additionally, the scope for structural diversity in molecular systems, imparting both tenability and tunability of desired electroactive properties, is expected to promote innovations in the area of shape-conformable piezo generators and sensors for wearable and implantable electronics. During the past decade, significant breakthroughs in piezoelectric soft materials such as polymers, soft crystals, and hybrid composites have promoted promising alternatives or supplements to conventional inorganic ceramics. ,,− However, a low piezoelectric coefficient and thereby poor output performance of the constructed generators/harvesters are major drawbacks in these systems for commercial applications.…”

Nanotubes and water-channels from self-assembling dipeptides

“…152 Inclusion of porphyrins has been used as a strategy to slow down the biodegradation of Phe-Phe NTs in physiological conditions towards uses in implantable medical devices. 153…”

“…152 Inclusion of porphyrins has been used as a strategy to slow down the biodegradation of Phe-Phe NTs in physiological conditions towards uses in implantable medical devices. 153 The blue photoluminescence of dipeptide NTs has been envisaged as a biolabel, for applications in bioimaging and biosensing, thanks also to its persistence upon thermal treatment at temperatures in the 140-180 1C range, at which NTs undergo a transition to nanowires. 154 Their variations in photoluminescence have been applied for temperature sensing, with precision of 1 1C in the range 5-65 1C.…”

Polarity‐Differentiated Dielectric Materials in Monolayer Graphene Charge‐Regulated Field‐Effect Transistors for an Artificial Reflex Arc and Pain‐Modulation System of the Spinal Cord

“…Most studies adopted a transistor with a back‐gate structure or a multi‐terminal planar structure to simulate the synaptic properties modulated by an interneuron. [ 49–52 ] However, the potentiation and depression of synapses were performed by using the opposite polarities of operating voltages or the requirement of additional switching methods, which are inconsistent with the features of the biological nervous system. Furthermore, interneurons without synaptic characteristics cannot simulate the functionalities of neuromodulation in a three‐terminal nervous system.…”