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The rapid development of gene therapy and genome editing techniques brings up an urgent need to develop safe and efficient nanoplatforms for nucleic acids and CRISPR genome editors. Herein we report a stimulus-responsive silica nanoparticle (SNP) capable of encapsulating biomacromolecules in their active forms with a high loading content and loading efficiency as well as a well-controlled nanoparticle size (~50 nm). A disulfide crosslinker was integrated into the silica network, endowing SNP with glutathione (GSH)-responsive cargo release capability when internalized by target cells. An imidazole-containing component was incorporated into the SNP to enhance the endosomal escape capability. The SNP can deliver various cargos, including nucleic acids (e.g., DNA and mRNA) and CRISPR genome editors (e.g., Cas9/sgRNA ribonucleoprotein (RNP), and RNP with donor DNA) with excellent efficiency and biocompatibility. The SNP surface can be PEGylated and functionalized with different targeting ligands. In vivo studies showed that subretinally injected SNP conjugated with all-trans-retinoic acid (ATRA) and intravenously injected SNP conjugated with GalNAc can effectively deliver mRNA and RNP to murine retinal pigment epithelium (RPE) cells and liver cells, respectively, leading to efficient genome editing. Overall, the SNP is a promising nanoplatform for various applications including gene therapy and genome editing.

Occlusion of blood vessel caused by thrombus is the major pathogenesis of various catastrophic cardiovascular diseases. Thrombus can be prevented or treated by antithrombotic drugs. However, free antithrombotic drugs often have relatively low therapeutic efficacy due to a number of limitations such as short half-life, unexpected bleeding complications, low thrombus targeting capability, and negligible hydrogen peroxide (H(2)O(2))-scavenging ability. Inspired by the abundance of H(2)O(2) and the active thrombus-targeting property of platelets, a H(2)O(2)-responsive platelet membrane-cloaked argatroban-loaded polymeric nanoparticle (PNP(Arg)) was developed for thrombus therapy. Poly(vanillyl alcohol-co-oxalate) (PVAX), a H(2)O(2)-degradable polymer, was synthesized to form an argatroban-loaded nanocore, which was further coated with platelet membrane. The PNP(Arg) can effectively target the blood clots due to the thrombus-homing property of the cloaked platelet membrane, and subsequently exert combined H(2)O(2)-scavenging effect via the H(2)O(2)-degradable nanocarrier polymer and antithrombotic effect via argatroban, the released payload. The PNP(Arg) effectively scavenged H(2)O(2) and protected cells from H(2)O(2)-induced cellular injury in RAW 264.7 cells and HUVECs. The PNP(Arg) rapidly targeted the thrombosed vessels and remarkably suppressed thrombus formation, and the levels of H(2)O(2) and inflammatory cytokine in the ferric chloride-induced carotid arterial thrombosis mouse model. Safety assessment indicated good biocompatibility of the PNP(Arg). Taken together, the biomimetic PNP(Arg) offers multifunctionalities including thrombus-targeting, antioxidation, and H(2)O(2)-stimulated antithrombotic action, thereby making it a promising therapeutic nanomedicine for thrombosis diseases.

Efficient delivery of hydrophilic drugs, nucleic acids, proteins, and any combination thereof is essential for various biomedical applications. Herein, we report a straightforward, yet versatile approach to efficiently encapsulate and deliver various hydrophilic payloads using a pH-responsive silica–metal–organic framework hybrid nanoparticle (SMOF NP) consisting of both silica and zeolitic imidazole framework (ZIF). This unique SMOF NP offers a high loading content and efficiency, excellent stability, and robust intracellular delivery of a variety of payloads, including hydrophilic small molecule drugs (e.g., doxorubicin hydrochloride), nucleic acids (e.g., DNA and mRNA), and genome-editing machineries (e.g., Cas9-sgRNA ribonucleoprotein (RNP), and RNP together with donor DNA (e.g., RNP + ssODN)). The superior drug delivery/gene transfection/genome-editing efficiencies of the SMOF NP are attributed to its pH-controlled release and endosomal escape capabilities due to the proton sponge effect enabled by the imidazole moieties in the SMOF NPs. Moreover, the surface of the SMOF NP can be easily customized (e.g., PEGylation and ligand conjugation) via various functional groups incorporated into the silica component. RNP-loaded SMOF NPs induced efficient genome editing in vivo in murine retinal pigment epithelium (RPE) tissue via subretinal injection, providing a highly promising nanoplatform for the delivery of a wide range of hydrophilic payloads.

An arch-structured triboelectric nanogenerator (TENG) was developed using nanofibrous poly(vinylidene fluoride-hexafluoropropylene) (PVDF-HFP) and nylon 6,6 (PA) membranes as the triboelectric pair and conductive fabrics as the electrodes. The nanofibrous microstructure and tribopolarity differences between the two triboelectric layers endow the TENG with outstanding triboelectric output performances, including an open-circuit voltage of 141.6 V and a short-circuit current of 20.4 μA. A maximum power density of 31.96 W m−2 was achieved at a load resistance of 106 Ω. The arch-structured TENG with such a high-power density has the ability to power portable small electronics, such as light-emitting-diodes (LEDs), liquid crystal displays (LCDs) and calculators. A self-powered sensing system was also fabricated using an arch-structured TENG and a signal processing circuit. The self-powered sensing system can readily detect the triboelectric signal generated by finger pressing and can effectively switch small electronics (e.g., an LED and a small motor) on and off. In addition, a TENG-based calculator was fabricated using 16 separate arch-structured TENGs that acted as the function keys of the calculator. Through real-time communication between a TENG-based calculator, a signal processing circuit and a computer, the TENG-based calculation system is able to complete the mathematical calculation process after the corresponding function keys were pressed. Therefore, an arch-structured TENG can not only power portable electronics, but also function as self-powered sensors in human-machine communication.

The CRISPR–Cas9 system is a powerful tool for genome editing, which can potentially lead to new therapies for genetic diseases. Up to date, various viral and non-viral delivery systems have been developed for the delivery of CRISPR-Cas9 in vivo. However, spatially and temporally controlled genome editing is needed to enhance the specificity in organs/tissues and minimize the off-target effects of editing. In this review, we summarize the state-of-the-art non-viral vectors that exploit external stimuli (i.e., light, magnetic field, and ultrasound) for spatially and temporally controlled genome editing and their in vitro and in vivo applications.

A double-network nanogel, composed of a silane-cross-linked polyethylenimine (PEI) network (i.e., PEI-S) and a pH-responsive poly(2-(hexamethyleneimino) ethyl methacrylate) (PC7A) polymer, was developed for efficient DNA transfection. The chemical cross-linking and hydrophobic interactions in the two networks led to improved stability outside the cell and also pH-triggered intracellular release of DNA. The nanogel with an optimal PEI-S and PC7A weight ratio of 1.3:1 exhibited significantly higher transfection efficiency than Lipofectamine 2000 in multiple cell lines. The nanogel also possessed a small size with a hydrodynamic diameter of 55 nm, low cytotoxicity, and superior stability in serum-containing media. Moreover, besides the PEI-based gene delivery system, we have also demonstrated that addition of the PC7A polymer to several types of cationic polymers commonly used for gene delivery also led to significant transfection enhancement of the resulting nanoparticles, suggesting that the PC7A polymer may be a universal additive that can benefit versatile cationic polymer-based gene delivery systems.

To meet the energy demand for flexible and miniaturized green electronics, it is highly desirable to develop a portable, cost-effective, lightweight, and sustainable power source through a facile and environment friendly approach. Herein, we report a portable, flexible, and low-cost self-charging power system (SCPS) consisting of a paper-based triboelectric nanogenerator (P-TENG) with high output power density as the energy harvester and a paper-based supercapacitor (P-SC) with a great areal capacitance as the energy storage device. A cellulose paper/polypyrrole composite with a low sheet resistance of 7.8 Ω sq–1 replaced the conventional metal electrodes and positive friction material in the P-TENG, as well as the capacitive material in the P-SC. The portable SCPS is capable of driving various miniaturized electronics such as a temperature/humidity indicator, thus demonstrating its potential as a sustainable power source for flexible and miniaturized green electronics.

Delivery technologies for the CRISPR-Cas9 (CRISPR, clustered regularly interspaced short palindromic repeats) gene editing system often require viral vectors, which pose safety concerns for therapeutic genome editing1. Alternatively, cationic liposomal components or polymers can be used to encapsulate multiple CRISPR components into large particles (typically >100 nm diameter); however, such systems are limited by variability in the loading of the cargo. Here, we report the design of customizable synthetic nanoparticles for the delivery of Cas9 nuclease and a single-guide RNA (sgRNA) that enables the controlled stoichiometry of CRISPR components and limits the possible safety concerns in vivo. We describe the synthesis of a thin glutathione (GSH)-cleavable covalently crosslinked polymer coating, called a nanocapsule (NC), around a preassembled ribonucleoprotein (RNP) complex between a Cas9 nuclease and an sgRNA. The NC is synthesized by in situ polymerization, has a hydrodynamic diameter of 25 nm and can be customized via facile surface modification. NCs efficiently generate targeted gene edits in vitro without any apparent cytotoxicity. Furthermore, NCs produce robust gene editing in vivo in murine retinal pigment epithelium (RPE) tissue and skeletal muscle after local administration. This customizable NC nanoplatform efficiently delivers CRISPR RNP complexes for in vitro and in vivo somatic gene editing. Polymer nanocapsules, assembled around a ribonucleoprotein complex of Cas9 nuclease and a single-guide RNA, enable safe and efficient gene editing in vitro and in vivo.

Cellulose-derived materials have gained a lot of attention for applications in advanced electronics because they are abundant, low cost, lightweight, and sustainable. Herein, we report a paper-based triboelectric nanogenerator (P-TENG) using commercially available materials derived from cellulose by a facile and cost-effective approach. Print paper is used as the substrate, while crepe cellulose paper (CCP) paired with a nitrocellulose membrane (NCM) are used as the friction layers of the P-TENG. CCP and NCM have significantly different tribopolarities and microstructures (i.e., corrugated and porous structures for CPP and NCM, respectively), thereby yielding P-TENGs with outstanding triboelectric performance. For instance, we have demonstrated P-TENGs with an output voltage and current of 196.8 V and 31.5 μA, respectively, a high power density of 16.1 W/m2, and a robust durability of more than 10,000 cycles. The P-TENGs, as a sustainable power source, can power various electronic devices. Moreover, their great potential applications in self-powered sensing and human–machine interfaces have been demonstrated. Human motion, like a finger touch, can be detected by the P-TENG. A keyboard based on an array of P-TENGs is able to achieve self-powered, real-time communication between a Paper Piano and a computer. This study not only combines the advantages of CCP and NCM to produce high-performance P-TENGs, but also demonstrates the feasibility of using commercially available products to prepare green and sustainable electronics.

Gene therapy holds great promise for various medical and biomedical applications. Nonviral gene delivery systems formed by cationic polymer and nucleic acids (e.g., polyplexes) have been extensively investigated for targeted gene therapy; however, their in vitro and in vivo stability is affected by both their intrinsic properties such as chemical compositions (e.g., polymer molecular weight and structure, and N/P ratio) and a number of environmental factors (e.g., shear stress during circulation in the bloodstream, interaction with the serum proteins, and physiological ionic strength). In this review, we surveyed the effects of a number of important intrinsic and environmental factors on the stability of polymeric gene delivery systems, and discussed various strategies to enhance the stability of polymeric gene delivery systems, thereby enabling efficient gene delivery into target cells. Future opportunities and challenges of polymeric nucleic acid delivery nanosystems were also briefly discussed.

To fulfill the increasing demand for radiofrequency (RF) wireless communication capacity for epidermal electronics, stretchable integrated circuits (ICs) in the gigahertz (GHz) range are desirable. Lumped RF inductors, as a key component in RFICs, typically dominate a large portion of the circuit/chip area and therefore make such inductors mechanically stretchable is critical for GHz-frequency stretchable RFICs. Most of the reported stretchable inductors operate in the MHz frequency range. The only GHz stretchable inductor shows a quality factor of about 2, limiting its potential RF applications. Here, stretchable inductors with a high quality factor of Q > 12.6 and resonance operation frequency of fres > 11.6 GHz are demonstrated by combining microspirals with stretchable structures, overcoming all of the shortcomings of previous demonstrations. Furthermore, a stretchable 1.5-2.6 GHz filter with a peak insertion loss of -2.3 dB at 1.8 GHz is developed, showing negligible performance changes under stretching or on the skin to demonstrate the utility in practical wireless applications like GSM and Bluetooth (2.45 GHz) bands. The demonstrations can facilitate multiple GHz epidermal RFICs in the future.

A major medical problem is the persistent lack of approved therapeutic methods to prevent postoperative intimal hyperplasia (IH) which leads to high-rate failure of open vascular reconstructions such as bypass grafting. Hydrogel has been widely used in preclinical trials for perivascular drug administration to mitigate postoperative IH. However, bulky hydrogel is potentially pro-inflammatory, posing a significant hurdle to clinical translation. Here we developed a new modality of directly "painting" drug-loaded unimolecular micelles (UM) to the adventitia thus obviating the need for a hydrogel. To render tissue adhesion, we generated amine-reactive unimolecular micelles with N-hydroxysuccinimide ester (UM-NHS) terminal groups to form stable amide bonds with the adventitia. To test periadventitial application, we either soaked balloon-injured rat carotid arteries in crosslinked UM-NHS (Mode-1) or non-crosslinked UM-NHS (Mode-2), or painted the vessel surface with non-crosslinked UM-NHS (Mode-3). The UM-NHS were loaded with or without a model drug (rapamycin) known to be IH inhibitory. We found that Mode-1 produced a marked IH-mitigating drug effect but also caused severe tissue damage. Mode-2 resulted in lower tissue toxicity yet less drug effect on IH. However, the painting method, Mode-3, demonstrated a pronounced therapeutic effect (75% inhibition of IH) without obvious toxicity. In summary, we present a simple painting modality of periadventitial local drug delivery using tissue-adhesive UM. Given the robust IH-abating efficacy and low tissue toxicity, this prototype merits further development towards an effective anti-stenosis therapy suitable for open vascular reconstructions.

Crosslinked polymer nanocapsules (CPNCs) are hollowed nanoparticles with network-like polymeric shells stabilized by primary bonds. CPNCs have drawn broad and significant interests as nanocarriers for biomedical applications in recent years. As compared with conventional polymeric nanoparticles systems without cavity and/or crosslinking architectures, CPNCs possess significant biomedical relevant advantages, including (a) superior structural stability against environmental conditions, (b) high loading capacity and ability for region-specific loading of multiple cargos, (c) tuneable cargo release rate via crosslinking density, and (d) high specific surface area to facilitate surface adsorption, modification, and interactions. With appropriate base polymers and crosslinkages, CPNCs can be biocompatible and biodegradable. While CPNC-based biomedical nanoplatforms can possess relatively stable physicochemical properties owing to their crosslinked architectures, various biomedically relevant stimuli-responsivities can be incorporated with them through specific structural designs. CPNCs have been studied for the delivery of small molecule drugs, genes, proteins, and other therapeutic agents. They have also been investigated as diagnostic platforms for magnetic resonance imaging, ultrasound imaging, and optical imaging. Moreover, CPNCs have been utilized to carry both therapeutics and bioimaging agents for theranostic applications. This article reviews the therapeutic, diagnostic and theranostic applications of CPNCs, as well as the preparation of these CPNCs, reported in the past decade. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease Implantable Materials and Surgical Technologies > Nanomaterials and Implants Diagnostic Tools > in vivo Nanodiagnostics and Imaging.

Low-cost flexible microwave circuits with compact size and light weight are highly desirable for flexible wireless communication and other miniaturized microwave systems. However, the prevalent studies on flexible microwave electronics have only focused on individual flexible microwave elements such as transistors, inductors, capacitors, and transmission lines. Thinning down supporting substrate of rigid chip-based monolithic microwave integrated circuits has been the only approach toward flexible microwave integrated circuits. Here, we report a flexible microwave integrated circuit strategy integrating membrane AlGaN/GaN high electron mobility transistor with passive impedance matching networks on cellulose nanofibril paper. The strategy enables a heterogeneously integrated and, to our knowledge, the first flexible microwave amplifier that can output 10 mW power beyond 5 GHz and can also be easily disposed of due to the use of cellulose nanofibril paper as the circuit substrate. The demonstration represents a critical step forward in realizing flexible wireless communication devices., Though flexible microwave integrated circuits (MICs) are desirable for the construction of functional microwave amplifier circuits, realizing low cost III-V-based MMICs remains a challenge. Here, the authors report a heterogeneous integration strategy for the fabrication of flexible low-cost MICs.

An abdominal aortic aneurysm (AAA) is a localized dilatation of the aorta that plagues millions. Its rupture incurs high mortality rates (~80-90%), pressing an urgent need for therapeutic methods to prevent this deadly outcome. Judiciously designed nanoparticles (NPs) have displayed a unique potential to fulfill this need. Aneurysms feature excessive inflammation and extracellular matrix (ECM) degradation. As such, typically inflammatory cells and exposed ECM proteins have been targeted with NPs for therapeutic, diagnostic, or theranostic purposes in experimental models. NPs have been used not only for encapsulation and delivery of drugs and biomolecules in preclinical tests, but also for enhanced imaging to monitor aneurysm progression in patients. Moreover, they can be readily modified with various molecules to improve lesion targeting, detectability, biocompatibility, and circulation time. This review updates on the progress, limitations, and prospects of NP applications in the context of AAA.

Gene therapy holds great promise for the treatment of many diseases, but clinical translation of gene therapies has been slowed by the lack of safe and efficient gene delivery systems. Here, we report two versatile redox-responsive polyplexes (i.e., crosslinked and non-crosslinked) capable of efficiently delivering a variety of negatively charged payloads including plasmid DNA (DNA), messenger RNA (mRNA), Cas9/gRNA ribonucleoprotein (RNP), and RNP-donor DNA complexes (S1mplex) without any detectable cytotoxicity. The key component of both types of polyplexes is a cationic poly(N,N’-bis(acryloyl)cystamine-co-triethylenetetramine) (p(BAC-TET)) polymer (a type of poly(N,N’-bis(acryloyl)cystamine-poly(aminoalkyl)) (PBAP) polymer) containing disulfide bonds in the backbone and bearing imidazole groups. This composition enables efficient encapsulation, cellular uptake, controlled endo/lysosomal escape, and cytosolic unpacking of negatively-charged payloads. To further enhance the stability of non-crosslinked PBAP polyplexes, adamantane (AD) and β-cyclodextrin (β-CD) were conjugated to the PBAP-based polymers. The crosslinked PBAP (CLPBAP) polyplexes formed by host–guest interaction between β-CD and AD were more stable than non-crosslinked PBAP polyplexes in the presence of polyanionic polymers such as serum albumin, suggesting enhanced stability in physiological conditions. Both crosslinked and non-crosslinked polyplexes demonstrated either similar or better transfection and genome editing efficiencies, and significantly better biocompatibility than Lipofectamine 2000, a commercially available state-of-the-art transfection agent that exhibits cytotoxicity.

Spatiotemporal control over the release or activation of biomacromolecules such as siRNA remains a significant challenge. Light-controlled release has gained popularity in recent years; however, a major limitation is that most photoactivable compounds/systems respond only to UV irradiation, but not near-infrared (NIR) light that offers a deeper tissue penetration depth and better biocompatibility. This paper reports a simple NIR-to-UV upconversion nanoparticle (UCNP)-based siRNA nanocarrier for NIR-controlled gene silencing. siRNA is complexed onto a NaYF4:Yb/Tm/Er UCNP through an azobenzene (Azo)–cyclodextrin (CD) host–guest interaction. The UV emission generated by the NIR-activated UCNP effectively triggers the trans-to-cis photoisomerization of azobenzene, thus leading to the release of siRNA due to unmatched host – guest pairs. The UCNP-siRNA complexes are also functionalized with PEG (i.e., UCNP-(CD/Azo)-siRNA/PEG NPs), targeting ligands (i.e., EGFR-specific GE11 peptide), acid-activatable cell-penetrating peptides (i.e., TH peptide), and imaging probes (i.e., Cy5 fluorophore). The UCNP-(CD/Azo)-siRNA/PEG NPs with both GE11 and TH peptides display a high level of cellular uptake and an excellent endosomal/lysosomal escape capability. More importantly, NIR-controlled spatiotemporal knockdown of GFP expression is successfully achieved in both a 2D monolayer cell model and a 3D multicellular tumor spheroid model. Thus, this simple and versatile nanoplatform has great potential for the selective activation or release of various biomacromolecules.

Finding new means to enhance the performance of triboelectric nanogenerators (TENGs) is an ongoing pursuit. We report a novel flexible TENG made of highly porous cellulose nanofibril (CNF)/polyethylenimine (PEI) aerogel film paired with polyvinylidene fluoride (PVDF) nanofiber mats that exhibits outstanding triboelectric outputs. Modifying CNF with PEI not only enhances the mechanical properties of the CNF/PEI aerogel, but also greatly improves the power density by 14.4 times due to the enhanced tribopositivity. The triboelectric performance is further improved by employing multiple layers of PVDF mats. The TENG made of the CNF/PEI aerogel paired with four layers of PVDF mats exhibited an 18.3 times and 97.6 times improvement in output voltage and power density, respectively, compared to the TENG made of one layer of PVDF mat. The peak output power density reached 13.3 W/m2 at a load resistance of 106 Ω. Furthermore, the novel TENG displays extraordinary sensitivity when used as a self-powered sensor. It can detect not only human motion like arm bending and footsteps, but also small forces like finger tapping, water dripping, and the vibration of the substrate it is attached to. Therefore, this study not only demonstrates a high performance TENG, but also provides new insights into the design, fabrication, and application of TENGs.

The long-sought promise of gene therapy for the treatment of human diseases remains unfulfilled, largely hindered by the lack of an efficient and safe delivery vehicle. In this study, we have developed a universal glutathione-responsive nanoplatform for the efficient delivery of negatively charged genetic biomacromolecules. The cationic block copolymer, poly(aspartic acid-(2-aminoethyl disulfide)-(4-imidazolecarboxylic acid))-poly(ethylene glycol), bearing imidazole residues and disulfide bonds, can form polyplexes with negatively charged DNA, mRNA, and Cas9/sgRNA ribonucleoprotein (RNP) through electrostatic interactions, which enable efficient cellular uptake, endosomal escape, and cytosol unpacking of the payloads. To facilitate the nuclear transport of DNA and RNP, the nuclear localization signal peptide was integrated into the DNA or RNP polyplexes. All three polyplex systems were fully characterized and optimized in vitro. Their relatively high transfection efficiency and low cytotoxicity, as well as convenient surface functionalization merit further investigation.

Polymeric unimolecular nanoparticles (NPs) exhibiting a core-shell structure and formed by a single multi-arm molecule containing only covalent bonds have attracted increasing attention for numerous biomedical applications. This unique single-molecular architecture provides the unimolecular NP with superior stability both in vitro and in vivo, a high drug loading capacity, as well as versatile surface chemistry, thereby making it a desirable nanoplatform for therapeutic and diagnostic applications. In this review, we surveyed the architecture of various types of polymeric unimolecular NPs, including water-dispersible unimolecular micelles and water-soluble unimolecular NPs used for the delivery of hydrophobic and hydrophilic agents, respectively, as well as their diverse biomedical applications. Future opportunities and challenges of unimolecular NPs were also briefly discussed.

A simple and effective strategy was developed to prepare a three-dimensional manganese oxynitride nanowire (MnOxNy)–reduced graphene oxide (RGO)–cellulose nanofibril (CNF) aerogel electrode with high areal mass loading (∼6.02 mg cm−2). The electrical conductivity and electrochemical performance of MnO2 nanowires were intrinsically improved by inducing oxygen vacancies and nitrogen doping during hydrazine vapor treatment. Due to the synergistic effects of highly conductive RGO, highly pseudocapacitive MnOxNy, a highly open and continuous porous aerogel structure, and the superior hydrophilicity of CNFs, the novel MnOxNy/RGO/CNF aerogel electrode we developed demonstrated a high capacitance of 455.8 F g−1 (2743.7 mF cm−2) and excellent rate capability. Pairing it with the similarly developed molybdenum oxynitride (MoOxNy)/RGO/CNF negative electrode, the asymmetric supercapacitors (ASCs) can achieve a high voltage window of 1.8 V, revealing a high energy density of 49.0 W h kg−1 at a power density of 953.7 W kg−1 in an aqueous electrolyte (i.e., 1.0 M Na2SO4 solution) and 43.7 W h kg−1 at a power density of 948.3 W kg−1 in a solid-state polymer gel electrolyte (i.e., poly(vinyl alcohol)/Na2SO4). This strategy for engineering high-performance electrodes with high mass loading will open up new opportunities for developing highly efficient energy storage devices for practical applications.

The ability to topographically mimic the surface features of collagen fibrils is an important step in the preparation of tissue engineering scaffolds. It is important to know which kinds of surface topographies of electrospun fibers are more favorable for cell growth. In this study, fibers with three kinds of hierarchical-structured surfaces were fabricated by electrospinning to mimic collagen fibrils. By combining thermally induced phase separation (TIPS) and non-solvent induced phase separation (NIPS), polycaprolactone (PCL) fibers with a porous surface were electrospun from PCL in a chloroform (CF)/dimethyl sulfoxide (DMSO) mixed solution. In addition, two additional types of fibrous membranes, with PCL fibers being the shish and decorated by PCL kebabs on the surface, were created by two different controlled homoepitaxic crystallization methods—the solution incubation method and the solvent evaporation method. It was found that the solvent evaporation method was more effective in forming kebabs and the primary optimal processing parameters were identified. The presence of pores on the fiber surfaces contributed to a much larger surface area and a higher total volume of pores. To investigate the cellular response on such scaffolds, 3T3 fibroblast cell and human umbilical vein endothelial cell (HUVEC) assays were conducted and the results indicated that both of the nanotopographies on the surfaces of the scaffolds improved cell viability and proliferation. Furthermore, the porous surface was more beneficial for enhancing cellular responses, which suggests better biocompatibility and greater potential to mimic collagen fibrils for tissue engineering application, and especially as scaffolds for endothelial layers in blood vessels.

Cancer remains a major threat to human health due to low therapeutic efficacies of currently available cancer treatment options. Nanotheranostics, capable of simultaneous therapy and diagnosis/monitoring of diseases, has attracted increasing amounts of attention, particularly for cancer treatment. In this study, CuS-based theranostic micelles capable of simultaneous combination chemotherapy and photothermal therapy (PTT), as well as photoacoustic imaging, were developed for targeted cancer therapy. The micelle was formed by a CuS nanoparticle (NP) functionalized by thermosensitive amphiphilic poly(acrylamide-acrylonitrile)–poly(ethylene glycol) block copolymers. CuS NPs under near-infrared (NIR) irradiation induced a significant temperature elevation, thereby enabling NIR-triggered PTT. Moreover, the hydrophobic core formed by poly(acrylamide-acrylonitrile) segments used for drug encapsulation exhibited an upper critical solution temperature (UCST; ~38 °C), which underwent a hydrophobic-to-hydrophilic transition once the temperature rose above the UCST induced by NIR-irradiated CuS NPs, thereby triggering a rapid drug release and enabling NIR-controlled chemotherapy. The CuS-based micelles conjugated with GE11 peptides were tested in an epidermal growth factor receptor-overexpressing triple-negative breast cancer model. In both two-dimensional monolayer cell and three-dimensional multicellular tumor spheroid models, GE11-tagged CuS-based micelles under NIR irradiation, enabling the combination chemotherapy and PTT, exhibited the best therapeutic outcome due to a synergistic effect. These CuS-based micelles also displayed a good photoacoustic imaging ability under NIR illumination. Taken together, this multifunctional CuS-based micelle could be a promising nanoplatform for targeted cancer nanotheranostics.

Flexible nanogenerators (NGs) that are capable of harvesting ubiquitous mechanical energy from ambient environments have attracted significant attention during the past decade. Herein, a simple and scalable technique has been demonstrated to fabricate a new class of high-performance flexible compact triboelectric NGs using porous aerogel films. These porous aerogel film-based NGs can exhibit significant electric outputs without the use of traditional piezoelectric materials or traditional triboelectric assembly (i.e., the need of airgap). To explain the high electric outputs generated from the porous aerogel film-based generators, a mechanoradical-based mechanism was proposed and a series of systematic studies were carried out to substantiate this new mechanism. These systematic studies have demonstrated that high-performance flexible NGs can be made from porous mechanoradical-generating polymer films. The outstanding electric outputs from this new family of compact triboelectric NGs can be attributed to the reversible and transient mechanoradicals resulting from bond breaking of polymer chain, thus leading to a significant amount of transient dipole moments, as well as the permanent electric dipole moments possessed by the mechanoradical-induced polar groups. The elucidation of the potential mechanisms for this family of porous mechanoradical-generating polymers will lead to a new class of energy harvesting materials and high-performance, low-cost, and flexible energy generation devices.

This paper presents the experimental behavior of low-energy impact and quasi-static compression test of shifted-tri-axial structural wood-fiber-based composite panels made from laminated paper. The experimental results were analyzed based on design parameters and configurations of panels for the further design and optimization. The results showed that the face stiffness and strength was a significant factor to improve both impact performance and compressive performance. The panels made with additional carbon fiber fabric composite faces had higher energy absorption compared with the same panels made without it. The core configuration also affected the impact behavior of the panels, the foam filled core integrated with the shifted-tri-axial rib structure improved the impact load and absorbed more energy than the same panels without the foam. Further, the structure and size of the element in the core influenced the impact performance and energy absorption. The location for both compression and impact at the triangular lattice element center of the ribs had higher absorbed energy than the location at the hexagonal lattice element center of the ribs. A 3D contour surface map of maximum energy absorption was made based on the experimental data, the contour shows localized energy absorption based on the impact location on the core, the small triangular lattice element of the core had highest maximum energy absorption of panels. For both the quasi-static compression tests and the low-velocity impact tests, the panels with the same core configuration had similar compressive load–displacement trends during the early contact phase. However, the peak load was higher in compression than the peak load for the low-velocity impact for panels with the same configuration.

A technique that can be used to viably create triaxially strained bilayer graphene on any desirable location by simple patterning was developed. Unlike the conventional graphene strain engineering methods, the photolithographically defined spoke patterns and compressive strained Si3N4 layer deposited by plasma-enhanced chemical vapor deposition (PECVD) system enable the creation of locally confined triaxial strained bilayer graphene at the desire location by forming a unique tristar shaped wrinkle. The tristar shaped wrinkle was investigated with high resolution micro-Raman spectroscopy and atomic force microscopy (AFM) analyses, and confirmed that 0.38% of maximum triaxial compressive strain was created. Mechanical simulation was used to verify the strain distribution and confirm the strain value which was calculated from the Raman spectroscopy and AFM profile. The technique presented here not only provides a practical route to the creation of strained graphene at desired locations but also offers the potential of the creation of multiaxial strain in the graphene for various types of graphene-based electronic and optoelectronic devices.

Medullary thyroid cancer (MTC) is often resistant to standard therapies, emphasizing the need for the development of other treatments. A new histone deacetylase inhibitor, AB3, can effectively inhibit MTC cell proliferation in vitro. However, its poor aqueous solubility and stability, fast clearance, and lack of tumor targeting ability limit its in vivo application. Therefore, multifunctional unimolecular micelles were developed for targeted delivery of AB3 for MTC therapy. The unimolecular micelles exhibited a spherical core–shell structure, uniform size distribution, and excellent stability. AB3 was encapsulated into the hydrophobic core of the unimolecular micelles, thus significantly enhancing its aqueous solubility and stability. KE108, a somatostatin analog possessing high affinity to all five subtypes of SSTR, was used as an MTC-targeting ligand. In vitro cellular uptake analyses demonstrated that the KE108 exhibited superior targeting ability in MTC cells compared to octreotide, the first clinically used somatostatin analog. Moreover, the AB3-loaded and KE108-conjugated unimolecular micelles exhibited the best efficacy in suppressing MTC cell growth and tumor marker expression in vitro. Furthermore, AB3-loaded, KE108-conjugated micelles demonstrated the best anticancer efficacy in vivo without any apparent systemic toxicity, thereby offering a promising approach for targeted MTC therapy.

A novel polydimethylsiloxane (PDMS)/cellulose nanocrystal flake (CNCF) composite triboelectric nanogenerator (CTG) using CNCFs as effective dielectrics exhibited a 10-times-enhanced triboelectric performance compared with its pure PDMS counterpart. Positive charges generated on the surface of the CNCFs during cyclic compression boosted electron transfer and induced extra charges. The CTG exhibited an instantaneous output power (density) of 1.65 mW (0.76 mW cm−2) under continuous operation.

A free-standing, lightweight, highly porous, and highly flexible cellulose nanofibril (CNF)–reduced graphene oxide (RGO)–molybdenum oxynitride (MoOxNy) aerogel film electrode was synthesized by freeze-drying a CNF/GO/MoO3 aqueous dispersion followed by subsequent in situ hydrazine reduction. Due to the partial reduction and nitrogen doping of the MoO3 nanobelts and the highly open and continuous porous structure, the free-standing CNF/RGO/MoOxNy aerogel film electrode delivered an outstanding specific capacitance of 680 F g−1 in an aqueous electrolyte and 518 F g−1 in an ionic liquid electrolyte in a three-electrode configuration at a current density of 1.0 A g−1. Furthermore, highly flexible and all-solid-state supercapacitors using CNF/RGO/MoOxNy as electrodes and either a hydrogel or ionogel as the electrolyte were fabricated and both types of supercapacitors demonstrated high specific capacitance and excellent long-term cycling stability. Remarkably, the solid-state supercapacitor devices fabricated using an ionogel electrolyte demonstrated an energy density of 114 W h kg−1 (corresponding to a volumetric energy density of 18.8 W h L−1), which is among the highest values achieved for any type of solid-state supercapacitor and is even comparable to the energy densities of Li-ion batteries. Therefore, this study provides a simple and cost-efficient method for fabricating flexible energy storage devices with excellent electrochemical performance.

Boosting power generation performance while employing economical and biocompatible materials is an ongoing direction in the field of triboelectric nanogenerators (TENGs). Here, highly porous, biocompatible, cellulose nanofibril (CNF) composite-based TENGs are developed through an environmentally friendly freeze-drying approach. High tribopositivity materials, including silica fiber, human hair, and rabbit fur, are used as fillers in composite TENG fabrication for the first time to enhance the triboelectric output performance. Among them, a CNF/rabbit fur composite aerogel-based TENG offers the optimum energy generation ability with a high power density of 3.4 W m−2 achieved on a 4.7 MΩ load at a pressure of 30 kPa. Owing to the high output, the porous composite TENG exhibits an excellent energy harvesting performance and high sensitivity in detecting ultralight forces and monitoring human motion when used as a self-powered sensor. This work introduces a new class of highly porous composite TENGs that integrate biocompatibility, low cost, flexibility, high energy generation performance, and sensing sensitivity, as well as providing new strategies for high performance TENG design and fabrication.

Antimicrobial resistant (AMR) infections are a growing threat to public health and there is a general lack of development in new antibiotics. Here, a dextran-coated stimuli-responsive nanoparticle (NP) that encapsulates the hydrophobic antibiotic, rifampicin, and specifically binds bacteria to overcome AMR infections is reported. The NP shows a strong affinity with a variety of pathogens in vitro and effectively accumulates in the bacterial infected tissues. The NP is activated by either low pH or high reactive oxygen species in the infectious microenvironment, and releases both cationic polymer and rifampicin that display synergistic activity against AMR pathogens. The NP carrier also enables the antibiotic to penetrate both bacterial biofilms and mammalian cells, thus allowing the elimination of biofilm and intracellular infections. The NP formulation demonstrates both safety and efficacy in two animal infection models against either Gram-negative or Gram-positive AMR pathogens.

Thrombosis is a principle cause of various life-threatening cardiovascular diseases. However, current antithrombotic treatments using drugs only offer limited efficacy due to short half-life, low targeting ability to the thrombus site, and unexpected bleeding complications. Taking into account of the biological characteristics of thrombus including upregulation of hydrogen peroxide (H2O2) and abundance of fibrin, we engineered a H2O2-responsive nanocarrier for thrombus-targeting delivery of an antithrombotic agent (i.e., tirofiban). The nanocarrier was composed of a drug-conjugated dextran nanocore and a red blood cell (RBC) membrane shell, and its surface was functionalized with a fibrin-targeting peptide, CREKA. Tirofiban was conjugated to dextran through a H2O2-cleavable phenylboronic ester linkage. The fibrin-targeting RBC membrane-cloaked dextran-tirofiban conjugate nanoparticles (i.e., T-RBC-DTC NPs) can scavenge H2O2 and provide controlled release of tirofiban to achieve site-specific antithrombotic effects. In RAW 264.7 cells and HUVECs, the T-RBC-DTC NPs effectively scavenged H2O2 and protected cells from H2O2-induced cytotoxicity. In the ferric chloride-induced carotid thrombosis mouse model, the T-RBC-DTC NPs efficiently accumulated at the injured carotid artery and exhibited significantly enhanced antithrombotic activity compared to free drug. The T-RBC-DTC NPs also exhibited good biocompatibility according to histology analysis. Overall, our results indicated that this bioengineered nanocarrier offers a promising therapeutic strategy for thrombotic disorders.

This paper presents an analysis of 3-dimensional engineered structural panels (3DESP) made from wood-fiber-based laminated paper composites. Since the existing models for calculating the mechanical behavior of core configurations within sandwich panels are very complex, a new simplified orthogonal model (SOM) using an equivalent element has been developed. This model considers both linear and nonlinear geometrical effects when used to analyze the mechanical properties of 3DESP by transforming repeated elements from a tri-axial ribbed core for bending. Two different conditions were studied in comparison with finite element method (FEM) and I-beam equation. The results showed the SOM was consistent with FEM and the experimental result and were more accurate than the I-beam equation. The SOM considering nonlinear geometric deformation needed more computational effort and was found to match well with a FEM model and had slightly better accuracy compared with the linear SOM. Compared with FEM, the parameters in the linear SOM were easier to modify for predicting point-by-point bending performance. However, while the FEM can provide advanced characteristics of the 3DESP such as strain distribution, the linear SOM provided acceptable deformation accuracy and is proposed for preliminary design with multiple parameters. FEM should be applied for advanced analyses.

Superhydrophobic and crosslinked poly(vinyl alcohol) (PVA)/cellulose nanofibril (CNF) aerogel microspheres were prepared via a combination of the water-in-oil (W/O) emulsification process with the freeze-drying process, followed by thermal chemical vapor deposition of methyltrichlorosilane. The oil phase and the cooling agent were judiciously selected to ensure that the frozen ice microspheres can be easily separated from the emulsion system. The silanized microspheres were highly porous with a bulk density ranging from 4.66 to 16.54mg/cm(3). The effects of the solution pH, stirring rate, and emulsifier concentration on the morphology and microstructure of the aerogel microspheres were studied. The highly porous structure of the ultralight aerogel microspheres demonstrated an ultrahigh crude oil absorption capacity (up to 116 times its own weight). This study provides a novel approach for the large-scale preparation of polymeric aerogel microspheres with well-controlled particle sizes that can be used for various applications including oil and chemical spill/leak clean-up.

Neuroendocrine (NE) cancers can cause significant patient morbidity. Besides surgery, there are no curative treatments for NE cancers and their metastases, emphasizing the need for the development of other forms of therapy. In this study, multifunctional unimolecular micelles were developed for targeted NE cancer therapy. The unimolecular micelles were formed by multi-arm star amphiphilic block copolymer poly(amidoamine)-poly(valerolactone)-poly(ethylene glycol) conjugated with KE108 peptide and Cy5 dye (abbreviated as PAMAM-PVL-PEG-KE108/Cy5). The unimolecular micelles with a spherical core-shell structure exhibited a uniform size distribution and excellent stability. The hydrophobic drug thailandepsin-A (TDP-A), a recently discovered HDAC inhibitor, was physically encapsulated into the hydrophobic core of the micelles. KE108 peptide, a somatostatin analog possessing high affinity for all five subtypes of somatostatin receptors (SSTR 1-5), commonly overexpressed in NE cancer cells, was used for the first time as an NE cancer targeting ligand. KE108 exhibited superior targeting abilities compared to other common somatostatin analogs, such as octreotide, in NE cancer cell lines. The in vitro assays demonstrated that the TDP-A-loaded, KE108-targeted micelles exhibited the best capabilities in suppressing NE cancer cell growth. Moreover, the in vivo near-infrared fluorescence imaging on NE-tumor-bearing nude mice showed that KE108-conjugated micelles exhibited the greatest tumor accumulation due to their passive targeting and active targeting capabilities. Finally, TDP-A-loaded and KE108-conjugated micelles possessed the best anticancer efficacy without detectable systemic toxicity. Thus, these novel TDP-A-loaded and KE108-conjugated unimolecular micelles offer a promising approach for targeted NE cancer therapy.

A novel, simple, cost-effective, and scalable technique was developed to fabricate high-performance flexible piezoelectric nanogenerators (NGs) using porous cellulose nanofibril (CNFs)/poly(dimethylsiloxane) (PDMS) aerogel film. The porous CNF/PDMS aerogel film was prepared by coating a layer of PDMS on the porous surface of a compressed CNF aerogel film produced via an environmentally friendly freeze-drying process. The porous CNF/PDMS aerogel film was then sandwiched between two thin PDMS films, followed by two aluminum foils, to form the flexible NGs. Under periodic external mechanical deformation by an oscillator, the resulting flexible porous CNF/PDMS aerogel film-based NGs exhibited very stable and high output piezoelectric signals; namely, an open-circuit voltage (Voc) of 60.2 V, a short-circuit current (Isc) of 10.1 μA, and a corresponding power density of 6.3 mW/cm3. The electric power generated by these NGs was able to directly turn on 19 blue light-emitting diodes (LEDs) and charge a capacitor up to 3.7 V. Furthermore, these NGs also demonstrated excellent stability and durability. Considering their excellent piezoelectric performance, ease of large-scale manufacturing, and environmental friendliness, this technology provides a promising solution for developing practical, flexible, and self-powered electronic devices.

Due to the overexpression of somatostatin receptors in neuroendocrine (NE) cancers, drug nanocarriers conjugated with somatostatin analogs, such as octreotide (OCT), for targeted NE cancer therapy may offer increased therapeutic efficacies and decreased adverse effects. In this study, OCT-functionalized unimolecular micelles were prepared using individual hyperbranched polymer molecules consisting of a hyperbranched polymer core (Boltorn(®) H40) and approximately 25 amphiphilic polylactide-poly(ethlyene glycol) (PLA-PEG) block copolymer arms (H40-PLA-PEG-OCH3/OCT). The resulting micelles, exhibiting a uniform core-shell shape and an average hydrodynamic diameter size of 66 nm, were loaded with thailandepsin-A (TDP-A), a relatively new naturally produced histone deacetylase (HDAC) inhibitor. In vitro studies using flow cytometry and confocal laser scanning microscopy (CLSM) demonstrated that OCT conjugation enhanced the cellular uptake of the unimolecular micelles. Consequently, TDP-A-loaded and OCT-conjugated micelles exhibited the highest cytotoxicity and caused the highest reduction of NE tumor markers. Finally, the in vivo studies on NE cancer bearing nude mice demonstrated that TDP-A-loaded and OCT-conjugated micelles possessed superior anticancer activity in comparison with other TDP-A formulations or drug alone, while showing no detectable systemic toxicity. Thus, these TDP-A-loaded and OCT-conjugated micelles offer a promising approach for targeted NE cancer therapy.

Stretchable electrical interconnects based on serpentines combined with elastic materials are utilized in various classes of wearable electronics. However, such interconnects are primarily for direct current or low-frequency signals and incompatible with microwave electronics that enable wireless communication. In this paper, design and fabrication procedures are described for stretchable transmission line capable of delivering microwave signals. The stretchable transmission line has twisted-pair design integrated into thin-film serpentine microstructure to minimize electromagnetic interference, such that the line's performance is minimally affected by the environment in close proximity, allowing its use in thin-film bioelectronics, such as the epidermal electronic system. Detailed analysis, simulations, and experimental results show that the stretchable transmission line has negligible changes in performance when stretched and is operable on skin through suppressed radiated emission achieved with the twisted-pair geometry. Furthermore, stretchable microwave low-pass filter and band-stop filter are demonstrated using the twisted-pair structure to show the feasibility of the transmission lines as stretchable passive components. These concepts form the basic elements used in the design of stretchable microwave components, circuits, and subsystems performing important radio frequency functionalities, which can apply to many types of stretchable bioelectronics for radio transmitters and receivers.

Wood pulp cellulose nanofibrils (CNF) thin film is a novel recyclable and biodegradable material. We investigated the microwave dielectric properties of the epoxy coated-CNF thin film for potential broad applications in flexible high speed electronics. The characterizations of dielectric properties were carried out in a frequency range of 1–10 GHz. The dielectric constant and loss tangent were extracted by using measurements of microstrip transmission lines that were built on the epoxy coated-CNF film and combined with Agilent Advanced Design System simulations. The RF property for the epoxy coated-CNF was compared to that of commercial polyethylene terephthalate film (PET). With the comparable microwave properties of non-biodegradable PET film, our study suggests that the epoxy coated-CNF film is a suitable biodegradable and environment-friendly substrate for flexible microwave and other applications.

This paper presents static and fatigue bending behavior for a wood-based structural panel having a slot and tab (S/T) construction technique. Comparisons were made with similarly fabricated panels without the S/T construction technique. Experimental results showed that both types of panels had similar bending properties in the static tests. However, the panels with S/T construction had better fatigue results. The failure modes were different for the two fabrication techniques. The panels without S/T debonded at the core:face interface. Whereas, the panels with S/T had cracks that propagated within the rib of the core after debonding damage at the core:face interface. The fatigue deflection-life relationship indicated that the S/T construction improved the connection between the faces and core. The S/T construction decreased the deflection growth rate that delayed panel failure. The fatigue stress-life relationship or degradation was better for the panels with S/T construction than the panels without the S/T construction.

This paper presents a simplified analytical model and balanced design approach for modeling light-weight wood-based structural panels in bending. Because many design parameters are required to input for the model of finite element analysis (FEA) during the preliminary design process and optimization, the equivalent method was developed to analyze the mechanical performance of panels based on experimental results. The bending deflection, normal strain and shear strain of the panels with various configurations were investigated using four point bending test. The results from the analytical model matched well with the experimental data, especially, the prediction for maximum deflection of the panels under failure load. The normal strain and shear strain calculated by the model also agreed with the experimental data. The failure criterion was determined by the failure modes using a 3-dimensional diagram with apparent normal and shear strain. For demonstration, panels 1 and 2 with a fixed core were modeled using the balanced design approach for optimal face thickness. The results showed that both the 3-dimensional diagram and analytical model provided similar thickness results, which were verified by the FEA for wood-based structural panels.

The self-healing capability is particularly desirable for multifunctional polymeric materials because it can make the materials more reliable, reduce repair costs, and extend their lifetime in many applications. Herein, a multi-stimuli responsive self-healing metallo-supramolecular polymer nanocomposite exhibiting superior mechanical properties was developed and demonstrated. Terpyridine ligand-terminated polyurethane (PU) was prepared by in situ polymerization on the surface of multi-walled carbon nanotubes (CNTs). The terpyridine ligand-terminated CNT/PU prepolymers were dynamically crosslinked with the metal ion Zn2+ to obtain a metallo-supramolecular polymer nanocomposite. The tensile strength and tensile strain-at-break of the CNT/PU polymer nanocomposite increased from 14.2 MPa and 620% to 22.8 MPa and 1076%, respectively, with the addition of Zn2+. The Zn2+-coordinated metallo-supramolecular polymer nanocomposite showed a rare combination of strong, tough, and elastic mechanical properties and was able to self-heal via multiple stimuli, including remotely controlled near infrared (NIR) light (4.2 mW mm−2, 30 min), relatively low temperatures (90 °C, 1 h), and/or solvents, all with excellent healing efficiencies (i.e., higher than 93%) and short healing times. Therefore, this unique multi-stimuli responsive self-healing metallo-supramolecular polymer nanocomposite has the potential to provide advances in structural component, microelectronic and sporting equipment applications, to name just a few.

Piezoresistive polymer nanocomposites are highly desirable for flexible mechanical sensing applications. In this study, a family of multi-walled carbon nanotube (CNT)/elastomeric triisocyanate-crosslinked polytetrahydrofuran (ETC-PTHF) nanocomposites that are highly stretchable and highly sensitive to mechanical stimuli were designed, synthesized, and characterized. The CNTs in the CNT/ETC-PTHF nanocomposites were initially dispersed in the ETC-PTHF matrix uniformly, leading to a relatively high electrical conductivity. Upon stretching, both the degree of CNT alignment along the stretching direction and the degree of PTHF crystallinity increased consistently with the tensile strain. The strain-induced microstructure change adversely affected the CNT conducting pathways, thereby reducing the electrical conductivity of the nanocomposites. For instance, the electrical conductivity of the 15 wt% CNT/ETC-PTHF nanocomposites decreased by approximately 7.3%, 29.2%, and 19.76, 169.2 and 1291 times when the tensile strain was 1%, 5%, 50%, 250%, and 500%, respectively. The nanocomposite film was able to detect a mechanical stimulus (poking) weaker than the landing force of a mosquito. Furthermore, the nanocomposite film demonstrated rapid and highly sensitive responses to continuous finger motion. These new piezoresistive CNT/ETC-PTHF nanocomposites possess a number of desirable characteristics including ease of fabrication, low cost, and high sensitivity, thereby making them very promising candidates for applications in electronic skins, electronic textiles, and biomedical detectors.

Fully biobased chemically crosslinked anisotropic carboxymethyl cellulose (CMC)/cellulose nanofibril (CNF) aerogels were prepared using an environmentally friendly directional freeze-drying method. The resulting cellulose aerogels were characterized using various techniques. It was found that the CMC/CNF aerogel exhibited a honeycomb structure, and thus possessed anisotropic properties. Moreover, the fully biobased crosslinked organic aerogel possessed excellent mechanical properties based on both compression and three-point bending tests. For instance, it exhibited a remarkable compressive modulus (up to 10 MPa) along the vertical direction (parallel to the freezing direction) as well as a high flexural modulus (up to 54 MPa) perpendicular to the freezing direction. The effects of different aerogel densities and CNF contents on the mechanical properties of CMC/CNF aerogels have been studied. With increasing aerogel density or CNF content, the modulus and strength of the CMC/CNF aerogel increased in both compression and three-point bending tests. In addition, these cellulose aerogels also exhibited relatively low thermal conductivities (

Triboelectric nanogenerators (TENGs) have been attracting a tremendous amount of attention since their discovery in 2012. Finding new means to enhance energy output is an ongoing pursuit. Herein, we introduce a new type of high-performance TENG composed of highly porous polyamide (PA) nanofiber mats and polyimide aerogel films. We have demonstrated that the thickness of the porous triboelectric materials, which is attained by stacking multiple layers of triboelectric materials, has a profound effect on the triboelectric output performance of TENGs. The triboelectric output increased when PA increased from one layer to six layers. However, it decreased when PA was further increased to 12 layers. With an optimum material thickness, a TENG with only a 2 cm2 effective device size achieved a high output voltage of 115 V and a current of 9.5 μA under a small compressive pressure (30 kPa). A peak power density of 1.84 W/m2 was achieved on a 4.7 MΩ external load. The TENG was able to light 60 light-emitting diodes easily and quickly charge capacitors with different capacitance to 6 V, indicating an outstanding energy harvesting ability. In addition, the performance of multiple TENGs connected in different ways, as well as the performance of TENGs in resistive/inductive/capacitive circuits, were investigated. These findings provide new insight into the working principles of TENGs in complex circuits.

The static and fatigue bending behavior of wood-fiber-based tri-axial engineered sandwich composite panels (ESCP) has been investigated by four-point bending tests. Fatigue panels and weakened panels (wESCP) with an initial interface defect were manufactured for the fatigue tests. Stress σ vs. number of cycles curves (S-N) were recorded under the different stress levels. The primary failure mode in the fatigue tests was observed in the shear zone (epoxy debonding), which was different from face failure in the pure bending zone for the static bending test. For residual bending (RB) test, epoxy debonding failure occurred between the pure bending zone and shear zone. Macro cracks along the core/face interface developed as the number of cycles increased during the fatigue life. The crack propagation or damage for the panels submitted to fatigue test can be described as a three-stage damage process of first non-linear portion, followed by linear damage accumulation, and lastly non-linear accelerated damage. Bending stiffness degradation at the higher load level had faster degradation during fatigue life. The dissipated energy of the panels was small due to the high stiffness of the materials.

A quantum-dot (QD)-based micelle conjugated with an anti-epidermal growth factor receptor (EGFR) nanobody (Nb) and loaded with an anticancer drug, aminoflavone (AF), has been engineered for EGFR-overexpressing cancer theranostics. The near-infrared (NIR) fluorescence of the indium phosphate core/zinc sulfide shell QDs (InP/ZnS QDs) allowed for in vivo nanoparticle biodistribution studies. The anti-EGFR nanobody 7D12 conjugation improved the cellular uptake and cytotoxicity of the QD-based micelles in EGFR-overexpressing MDA-MB-468 triple-negative breast cancer (TNBC) cells. In comparison with the AF-encapsulated nontargeted (i.e., without Nb conjugation) micelles, the AF-encapsulated Nb-conjugated (i.e., targeted) micelles accumulated in tumors at higher concentrations, leading to more effective tumor regression in an orthotopic triple-negative breast cancer xenograft mouse model. Furthermore, there was no systemic toxicity observed with the treatments. Thus, this QD-based Nb-conjugated micelle may serve as an effective theranostic nanoplatform for EGFR-overexpressing cancers such as TNBCs.

At present, there are no clinical options for preventing neointima-caused (re)stenosis after open surgery such as bypass surgery for treating flow-limiting vascular disease. Perivascular drug delivery is a promising strategy, but in translational research, it remains a major challenge to achieve long-term (e.g., > 3 months) anti(re)stenotic efficacy. In this study, we engineered a unique drug delivery system consisting of durable unimolecular micelles, formed by single multiarm star amphiphilic block copolymers with only covalent bonds, and a thermosensitive hydrogel formed by a poly(lactide-co-glycolide)–poly(ethylene glycol)–poly(lactide-co-glycolide) triblock copolymer (abbreviated as triblock gel) that is stable for about 4 weeks in vitro. The drug-containing unimolecular micelles (UMs) suspended in Triblock gel were able to sustain rapamycin release for over 4 months. Remarkably, even 3 months after perivascular application of the rapamycin-loaded micelles in Triblock gel in the rat model, the intimal/medial area ratio (a restenosis measure) was still 80% inhibited compared to the control treated with empty micelle/gel (no drug). This could not be achieved by applying rapamycin in Triblock gel alone, which reduced the intimal/medial ratio only by 27%. In summary, we created a new UM/Triblock gel hybrid system for perivascular drug delivery, which produced a rare feat of 3-month restenosis inhibition in animal tests. This system exhibits a real potential for further translation into an anti(re)stenotic application with open surgery.

Digital image sensors in hemispherical geometries offer unique imaging advantages over their planar counterparts, such as wide field of view and low aberrations. Deforming miniature semiconductor-based sensors with high-spatial resolution into such format is challenging. Here we report a simple origami approach for fabricating single-crystalline silicon-based focal plane arrays and artificial compound eyes that have hemisphere-like structures. Convex isogonal polyhedral concepts allow certain combinations of polygons to fold into spherical formats. Using each polygon block as a sensor pixel, the silicon-based devices are shaped into maps of truncated icosahedron and fabricated on flexible sheets and further folded either into a concave or convex hemisphere. These two electronic eye prototypes represent simple and low-cost methods as well as flexible optimization parameters in terms of pixel density and design. Results demonstrated in this work combined with miniature size and simplicity of the design establish practical technology for integration with conventional electronic devices., Hemispherical format has been adopted in camera systems to better mimic human eyes, yet the current designs rely on complicated fabrications. Here, Zhang et al. show an origami-inspired approach that enables planar silicon-based photodetector arrays to reshape into concave or convex geometries.