Smart materials can respond to stimuli and adapt their responses based on external cues from their environments. Such behavior requires a way to transport energy efficiently and then convert it for use in applications such as actuation, sensing, or signaling. Ultrasound can carry energy safely and with low losses through complex and opaque media. It can be localized to small regions of space and couple to systems over a wide range of time scales. However, the same characteristics that allow ultrasound to propagate efficiently through materials make it difficult to convert acoustic energy into other useful forms. Recent work across diverse fields has begun to address this challenge, demonstrating ultrasonic effects that provide control over physical and chemical systems with surprisingly high specificity. Here, we review recent progress in ultrasound-matter interactions, focusing on effects that can be incorporated as components in smart materials. These techniques build on fundamental phenomena such as cavitation, microstreaming, scattering, and acoustic radiation forces to enable capabilities such as actuation, sensing, payload delivery, and the initiation of chemical or biological processes. The diversity of emerging techniques holds great promise for a wide range of smart capabilities supported by ultrasound and poses interesting questions for further investigations.

The robust, anisotropic tobacco mosaic virus (TMV) provides a monodisperse particle size and defined surface chemistry. Owing to these properties, it became an excellent bio-template for the synthesis of diverse nanostructured organic/inorganic functional materials. For selective mineralization of the bio-template, specific functional groups were introduced by means of different genetically encoded amino acids or peptide sequences into the polar virus surface. An alternative approach for TMV surface functionalization is chemical coupling of organic molecules. To achieve mineralization control in this work, we developed a synthetic strategy to manipulate the surface hydrophilicity of the virus through covalent coupling of polymer molecules. Three different types of polymers, namely the perfluorinated (poly(pentafluorostyrene) (PFS)), the thermo-responsive poly(propylene glycol) acrylate (PPGA), and the block-copolymer polyethylene-block-poly(ethylene glycol) were examined. We have demonstrated that covalent attachment of hydrophobic polymer molecules with proper features retains the integrity of the virus structure. In addition, it was found that the degree of the virus hydrophobicity, examined via a ZnS mineralization test, could be tuned by the polymer properties.

DNA logic circuits have great potential for biocompatible and programmable computations; however, current designs require reset processes, which restrict real-time data processing and memory functionality. This study proposes a reset-free approach on the basis of toehold-mediated chain reaction (TCR), which enables continuous and reversible strand migration within dual-rail units. By localizing TCR components on two-dimensional DNA origami templates, various combinational logic gates (e.g., AND and OR gates) and memory elements were implemented, including set-reset and data latches, as well as advanced cascaded registers. These circuits consistently processed new inputs and retained outputs over multiple sequential operations. The proposed reset-free TCR framework offers a mechanism most analogous to electronic circuit operation and demonstrates considerable potential for practical applications in biosensing, diagnostics, and synthetic biology.

Polymerase-mediated DNA synthesis is fundamental to numerous biotechnology applications, but existing programmable synthesis methods depend on exchanging DNA building blocks, thereby increasing reagent use and complicating multistep workflows. Here, we introduce the TEmperature Mediated Primer Exchange Reaction (TEMPER), a programmable platform for arbitrary DNA synthesis that operates solely through temperature control without solution exchange. TEMPER uses hairpin DNA as temperature-responsive building blocks that define specific temperature range for DNA synthesis. The temperature range is determined by the length design of the hairpin, which regulates thermodynamic interactions between DNA molecules and allows selective and sequential DNA synthesis in one-pot. We validate its versatility by developing a DNA data storage writer, a colorimetric temperature indicator, and a temperature data logger, highlighting its broad potential in nanotechnology and biotechnology applications.