An official website of the United States government
Understanding the pulsing dynamics of tissue and fluids in the intracranial environment is an evolving research theme aimed at gaining new insights into brain physiology and disease progression. This article provides an overview of related research in magnetic resonance imaging, ultrasound medical diagnostics and mathematical modelling of biological tissues and fluids. It highlights recent developments, illustrates current research goals and emphasizes the importance of collaboration between these fields.
more »
« less
A palette of rechargeable mechanoluminescent fluids produced by a biomineral-inspired suppressed dissolution approach
Mechanoluminescent materials, which emit light in response to mechanical stimuli, have recently been explored as promising candidates for photonic skins, remote optogenetics, and stress sensing. All mechanoluminescent materials reported thus far are bulk solids with microns-sized grains, and their light emission is only produced when fractured or deformed in bulk form. In contrast, mechanoluminescence has never been observed in liquids and colloidal solutions, thus limiting its biological application in living organisms. Here we report the synthesis of mechanoluminescent fluids via a suppressed dissolution approach. We demonstrate that this approach yields stable colloidal solutions comprising mechanoluminescent nanocrystals with bright emission in the range of 470-610 nm and diameters down to 20 nm. These colloidal solutions can be recharged and discharged repeatedly under photoexcitation and hydrodynamically focused ultrasound, respectively, thus yielding rechargeable mechanoluminescent fluids that can store photon energy in a reversible manner. This rechargeable fluid can facilitate a systemically delivered light source gated by tissue-penetrant ultrasound for biological applications that require light in the tissue, such as optogenetic stimulation in the brain.
more »
« less
- Award ID(s):
- 2045120
- PAR ID:
- 10357504
- Date Published:
- Journal Name:
- Journal of the American Chemical Society
- ISSN:
- 1520-5126
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
-
Abstract Colloidal all‐inorganic lead halide perovskite quantum dots (QDs) are high‐performance light‐emitting materials with size‐dependent optical properties and can be readily synthesized by mixing ionic precursors. However, the low formation energy of the perovskite lattice makes their growth too fast to control under regular reaction conditions. Diffusion‐regulated CsPbBr3perovskite QD growth is reported on a nanometer‐sized liquid/liquid (L/L) interface supported in a micropipette tip without long‐chain organic ligands. The precursors are divided into two immiscible solutions across the L/L interface to avoid additional nucleation, and the QD growth kinetics are regulated by the constrained cationic diffusion field depending on the size of the micropipette tip. QDs with unprecedentedly small sizes (2.7 nm) are obtained due to the slowed‐down growth rates. The synthesis approach demonstrates the potential of micro‐controlled colloidal QD synthesis for mechanistic studies and micro‐fabrications.more » « less
-
Colloidal semiconductor nanocrystals (NCs) have emerged as promising candidates for developing solutionprocessable optical gain media with potential applications in integrated photonic circuits and lasers. However, the deployment of NCs in these technologies has been hindered by the nonradiative Auger recombination of multiexciton states, which shortens the optical gain lifetime and reduces its spectral range. Here, we demonstrate that these limitations can be overcome by using giant colloidal quantum shells (g-QSs), comprising a quantum-confined CdSe shell grown over a large (∼14 nm) CdS bulk core. Such bulk-nanoscale architecture minimizes exciton− exciton interactions, leading to suppressed Auger recombination and one of the broadest gain bandwidths reported for colloidal nanomaterials, spanning energies both above and, remarkably, below the bandgap. Ultrafast transient absorption and photoluminescence measurements demonstrate that the high-energy portion of optical gain arises from states containing more than 15 excitons per particle, while the unusual sub-bandgap gain behavior results from an Auger-assisted radiative recombination, a mechanism that has traditionally been viewed as a loss pathway. Collectively, these results reveal a unique gain regime associated with bulk-nanocrystal hybrid systems, which offers a promising path toward solution-processable light sources.more » « less
-
Rizzo, Piervincenzo; Su, Zhongqing; Ricci, Fabrizio; Peters, Kara J (Ed.)he further signal processing for wave signal extraction as in displacement-based detection systems. However, due to both interfering lights coming from sample surface, the collected light in a fiber-optic-based Sagnac interferometer system is very weak when applied to biological tissue, where the refractive index of tissue and air are close. The objective of this paper is to study the feasibility using a compact fiber-optic Sagnac interferometer to detect vibrational waves on a biological tissue surface. An actuator made with a 10mm x 10mm x 3mm piezoelectric chip loaded on a 3D-printed polymer-made prism-shaped wedge (1cm x1cm x1cm) was used for ultrasound surface wave excitation. A bulk copolymer-in-oil phantom (100mm diameter with 27mm height) was used to mimic biological tissues. A compact fiber-optic-based interferometer was used to detect the propagation of surface waves in the tissue mimicking phantom and the wave propagation speeds were determined based on the wave detection. Young’s modulus was calculated based on the measured wave speed on the phantom surface. A tensile testing machine was used to measure the Young’s modulus in a compression mode as a comparison. The results were compared.more » « less
-
This paper presents the development of novel rechargeable cement-based batteries with carbon fiber mesh for energy storage applications. With the increasing demand for sustainable energy storage solutions, there is a growing interest in exploring unconventional materials and technologies. The batteries featured the carbon fiber mesh, which coated with nickel oxide and iron materials as electrodes and immersed in a cement-based electrolyte, offering a unique approach to energy storage. Experimental investigations, including electrochemical impedance spectroscopy, cyclic voltammetry, charge-discharge cycling, and rate performance assessments, were conducted to evaluate the batteries' performance. Results indicated that the batteries have promising features such as high ionic conductivity of the cement-based electrolyte and stable charge-discharge behaviors over 100 cycles. Cyclic voltammetry curves demonstrated quasi-reversible redox peaks, indicative of battery-type electrochemistry. The rechargeable cement-based batteries exhibited stability in discharge capacity, efficiency, and energy density, surpassing existing literatures on cement batteries, with a maximum energy density of 7.6 Wh/ m2. Despite challenges related to efficiency and energy density, this paper envisions the practical applications for the batteries, from powering light sensors to supporting 5G base stations and meeting daily electricity needs. Integration of rechargeable cement-based batteries and clean energy sources holds significant promise for global energy storage solutions. In conclusion, this research provides valuable insights into developing rechargeable cement-based batteries, highlights their potential as sustainable energy storage solutions with opportunities for further optimization and future advancements.more » « less
- Free Publicly Accessible Full Text
-
Accepted Manuscript1.0
- Journal Article:
- The DOI is not currently available.
