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The present work demonstrates the manufacturing process of a pneumatic bellow actuator with an embedded sensor, utilizing a novel manufacturing approach through the complete use of additive manufacturing techniques, such as direct ink writing (DIW) and traditional fused deposition modeling (FDM) methods. This study is innovative in its integration of a dielectric electroactive polymer (DEAP) structure with sensing electrodes made of conductive carbon grease (CCG), showcasing a unique application of a 3D-printed DEAP with CCG electrodes for combined DEAP sensing and pneumatic actuation. Initial experiments, supported by computational simulations, evaluated the distinct functionality of the DEAP sensor by itself under various pressure conditions. The findings revealed a significant change in capacitance with applied pressure, validating the sensor's performance. After sensor validation, an additive manufacturing process for embedding the DEAP structure into a soft pneumatic actuator was created, exhibiting the system's capability for dual sensing and actuation, as the embedded sensor effectively responded to applied actuation pressure. This dual functionality represents an advancement in soft actuators, especially in applications that require integrated and responsive actuation and sensing capabilities. This work also represents a preliminary step in the development of a 3D-printed dual-modality actuator (pneumatic and electrically activated DEAP) with embedded sensing.

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Ferroelectric materials are utilized in many applications ranging from capacitors to data storage. The hysteresis frequency dependence of ferroelectric materials has been well studied. However, the long-term dynamic behavior including aging has not been well documented due to the long time frame required to gather experimental data, but it is critical for understanding the lifespan of these materials in application. Previous work has shown that the hysteresis frequency dependence of dielectric properties can be accurately modeled in the time domain using fractional derivative operators applied on a large frequency bandwidth. Currently, the lowest frequencies tested have been restrained to the hysteresis cycle quasi-static threshold. Below this threshold, the hysteresis shape remains unchanged. This research expands the current knowledge by validating the use of fractional derivative operators in long-term aging models. The model data are experimentally validated using aged piezoelectric samples up to 107 s. These results confirm that the low and high dynamic dielectric material behaviors are linked and can be consequently modeled using fractional derivative operators.

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A one-step approach towards the synthesis of folic acid (FA) coated silver nanoparticles (AgNPs) and doxorubicin (DOX) for drug delivery is proposed. The FA-AgNPs were 23 +/- 2 nm in diameter and showed good monodispersity with a characteristic surface plasmon peak at 409 nm. Taking advantage of the enhanced Raman signal of FA on AgNPs and targeting specificity of FA to folate-receptor expressing cancer cells, the as-prepared FA-AgNPs showed excellent receptor-mediated cellular uptake, as demonstrated both by surface enhanced raman scattering (SERS) imaging and fluorescent lifetime imaging (FLIM). Next, a chemotherapeutic drug, DOX was attached to the FA-AgNPs surface through electrostatic bonding and the release of DOX from FA-AgNPs was monitored by FLIM. The release of DOX into the cytoplasm after 4 hours of incubation was clearly seen by FLIM. After 8 hours, the cells underwent cell death due to the release of DOX from nanoparticles. However, in control cell lines with low-expression levels of the FA receptor, no scattering signal from AgNPs could be observed from within the cells even after an incubation period of 24 hours. Our study shows that nanocarriers can be designed with various chemistries to study targeting and release of disease-specific drugs.

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This study exhibits the fabrication of target-specific Gold nanorods (GNRs) coupled with an anti-tumorigenic apoptotic drug and provides tracking of the labeled particles as they migrate through cells and release their drug-load to targeted cancer cells. We utilize the photoluminescence property of GNRs and their ability to be conjugated with multiple agents to transform facile rods to a targeted drug delivery vehicle. GNRs of aspect ratio 2.8 were conjugated with a targeting ligand, folic acid and an anthracycline drug, Doxorubicin. The multifunctional nanorods were then used to target folate receptor expressing cancers cells for the delivery of a concentration dependent dosage of Doxorubicin (DOX). By utilizing the photoluminescence of GNRs and the innate fluorescence of DOX, multi-photon fluorescence lifetime imaging was utilized to monitor the uptake of functionalized nanorods, the release of the drug and its localization in living cells. We show that these nano-vehicles successfully targeted cancer cells over expressing folate receptors and showed low toxicity to control cell lines. Release of DOX was observed in the cytoplasmic region and after 16 h was found to be redistributed in the nucleus resulting in cell death. Our theragnostic approach demonstrates the fabrication of multifunctional GNRs for targeted drug delivery and monitoring of the drug and the vehicle by multi-photon microscopy using fluorescence intensity and lifetime imaging.

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Gold nanoprobes have become attractive diagnostic and therapeutic agents in medicine and life sciences research owing to their reproducible synthesis with atomic level precision, unique physical and chemical properties, versatility of their morphologies, flexibility in functionalization, ease of targeting, efficiency in drug delivery and opportunities for multimodal therapy. This review highlights some of the recent advances and the potential for gold nanoprobes in theranostics.

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We demonstrate a facile, one-step, protein-directed approach to preparing a new functional reduced graphene oxide via simultaneous reduction and surface functionalization of graphene oxide sheets with herceptin and show its potential application as a novel biological imaging agent.

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